v4.19.13 snapshot.
diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
new file mode 100644
index 0000000..4dd6faa
--- /dev/null
+++ b/fs/btrfs/extent_io.c
@@ -0,0 +1,5902 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/bitops.h>
+#include <linux/slab.h>
+#include <linux/bio.h>
+#include <linux/mm.h>
+#include <linux/pagemap.h>
+#include <linux/page-flags.h>
+#include <linux/spinlock.h>
+#include <linux/blkdev.h>
+#include <linux/swap.h>
+#include <linux/writeback.h>
+#include <linux/pagevec.h>
+#include <linux/prefetch.h>
+#include <linux/cleancache.h>
+#include "extent_io.h"
+#include "extent_map.h"
+#include "ctree.h"
+#include "btrfs_inode.h"
+#include "volumes.h"
+#include "check-integrity.h"
+#include "locking.h"
+#include "rcu-string.h"
+#include "backref.h"
+#include "disk-io.h"
+
+static struct kmem_cache *extent_state_cache;
+static struct kmem_cache *extent_buffer_cache;
+static struct bio_set btrfs_bioset;
+
+static inline bool extent_state_in_tree(const struct extent_state *state)
+{
+ return !RB_EMPTY_NODE(&state->rb_node);
+}
+
+#ifdef CONFIG_BTRFS_DEBUG
+static LIST_HEAD(buffers);
+static LIST_HEAD(states);
+
+static DEFINE_SPINLOCK(leak_lock);
+
+static inline
+void btrfs_leak_debug_add(struct list_head *new, struct list_head *head)
+{
+ unsigned long flags;
+
+ spin_lock_irqsave(&leak_lock, flags);
+ list_add(new, head);
+ spin_unlock_irqrestore(&leak_lock, flags);
+}
+
+static inline
+void btrfs_leak_debug_del(struct list_head *entry)
+{
+ unsigned long flags;
+
+ spin_lock_irqsave(&leak_lock, flags);
+ list_del(entry);
+ spin_unlock_irqrestore(&leak_lock, flags);
+}
+
+static inline
+void btrfs_leak_debug_check(void)
+{
+ struct extent_state *state;
+ struct extent_buffer *eb;
+
+ while (!list_empty(&states)) {
+ state = list_entry(states.next, struct extent_state, leak_list);
+ pr_err("BTRFS: state leak: start %llu end %llu state %u in tree %d refs %d\n",
+ state->start, state->end, state->state,
+ extent_state_in_tree(state),
+ refcount_read(&state->refs));
+ list_del(&state->leak_list);
+ kmem_cache_free(extent_state_cache, state);
+ }
+
+ while (!list_empty(&buffers)) {
+ eb = list_entry(buffers.next, struct extent_buffer, leak_list);
+ pr_err("BTRFS: buffer leak start %llu len %lu refs %d bflags %lu\n",
+ eb->start, eb->len, atomic_read(&eb->refs), eb->bflags);
+ list_del(&eb->leak_list);
+ kmem_cache_free(extent_buffer_cache, eb);
+ }
+}
+
+#define btrfs_debug_check_extent_io_range(tree, start, end) \
+ __btrfs_debug_check_extent_io_range(__func__, (tree), (start), (end))
+static inline void __btrfs_debug_check_extent_io_range(const char *caller,
+ struct extent_io_tree *tree, u64 start, u64 end)
+{
+ if (tree->ops && tree->ops->check_extent_io_range)
+ tree->ops->check_extent_io_range(tree->private_data, caller,
+ start, end);
+}
+#else
+#define btrfs_leak_debug_add(new, head) do {} while (0)
+#define btrfs_leak_debug_del(entry) do {} while (0)
+#define btrfs_leak_debug_check() do {} while (0)
+#define btrfs_debug_check_extent_io_range(c, s, e) do {} while (0)
+#endif
+
+#define BUFFER_LRU_MAX 64
+
+struct tree_entry {
+ u64 start;
+ u64 end;
+ struct rb_node rb_node;
+};
+
+struct extent_page_data {
+ struct bio *bio;
+ struct extent_io_tree *tree;
+ /* tells writepage not to lock the state bits for this range
+ * it still does the unlocking
+ */
+ unsigned int extent_locked:1;
+
+ /* tells the submit_bio code to use REQ_SYNC */
+ unsigned int sync_io:1;
+};
+
+static int add_extent_changeset(struct extent_state *state, unsigned bits,
+ struct extent_changeset *changeset,
+ int set)
+{
+ int ret;
+
+ if (!changeset)
+ return 0;
+ if (set && (state->state & bits) == bits)
+ return 0;
+ if (!set && (state->state & bits) == 0)
+ return 0;
+ changeset->bytes_changed += state->end - state->start + 1;
+ ret = ulist_add(&changeset->range_changed, state->start, state->end,
+ GFP_ATOMIC);
+ return ret;
+}
+
+static void flush_write_bio(struct extent_page_data *epd);
+
+int __init extent_io_init(void)
+{
+ extent_state_cache = kmem_cache_create("btrfs_extent_state",
+ sizeof(struct extent_state), 0,
+ SLAB_MEM_SPREAD, NULL);
+ if (!extent_state_cache)
+ return -ENOMEM;
+
+ extent_buffer_cache = kmem_cache_create("btrfs_extent_buffer",
+ sizeof(struct extent_buffer), 0,
+ SLAB_MEM_SPREAD, NULL);
+ if (!extent_buffer_cache)
+ goto free_state_cache;
+
+ if (bioset_init(&btrfs_bioset, BIO_POOL_SIZE,
+ offsetof(struct btrfs_io_bio, bio),
+ BIOSET_NEED_BVECS))
+ goto free_buffer_cache;
+
+ if (bioset_integrity_create(&btrfs_bioset, BIO_POOL_SIZE))
+ goto free_bioset;
+
+ return 0;
+
+free_bioset:
+ bioset_exit(&btrfs_bioset);
+
+free_buffer_cache:
+ kmem_cache_destroy(extent_buffer_cache);
+ extent_buffer_cache = NULL;
+
+free_state_cache:
+ kmem_cache_destroy(extent_state_cache);
+ extent_state_cache = NULL;
+ return -ENOMEM;
+}
+
+void __cold extent_io_exit(void)
+{
+ btrfs_leak_debug_check();
+
+ /*
+ * Make sure all delayed rcu free are flushed before we
+ * destroy caches.
+ */
+ rcu_barrier();
+ kmem_cache_destroy(extent_state_cache);
+ kmem_cache_destroy(extent_buffer_cache);
+ bioset_exit(&btrfs_bioset);
+}
+
+void extent_io_tree_init(struct extent_io_tree *tree,
+ void *private_data)
+{
+ tree->state = RB_ROOT;
+ tree->ops = NULL;
+ tree->dirty_bytes = 0;
+ spin_lock_init(&tree->lock);
+ tree->private_data = private_data;
+}
+
+static struct extent_state *alloc_extent_state(gfp_t mask)
+{
+ struct extent_state *state;
+
+ /*
+ * The given mask might be not appropriate for the slab allocator,
+ * drop the unsupported bits
+ */
+ mask &= ~(__GFP_DMA32|__GFP_HIGHMEM);
+ state = kmem_cache_alloc(extent_state_cache, mask);
+ if (!state)
+ return state;
+ state->state = 0;
+ state->failrec = NULL;
+ RB_CLEAR_NODE(&state->rb_node);
+ btrfs_leak_debug_add(&state->leak_list, &states);
+ refcount_set(&state->refs, 1);
+ init_waitqueue_head(&state->wq);
+ trace_alloc_extent_state(state, mask, _RET_IP_);
+ return state;
+}
+
+void free_extent_state(struct extent_state *state)
+{
+ if (!state)
+ return;
+ if (refcount_dec_and_test(&state->refs)) {
+ WARN_ON(extent_state_in_tree(state));
+ btrfs_leak_debug_del(&state->leak_list);
+ trace_free_extent_state(state, _RET_IP_);
+ kmem_cache_free(extent_state_cache, state);
+ }
+}
+
+static struct rb_node *tree_insert(struct rb_root *root,
+ struct rb_node *search_start,
+ u64 offset,
+ struct rb_node *node,
+ struct rb_node ***p_in,
+ struct rb_node **parent_in)
+{
+ struct rb_node **p;
+ struct rb_node *parent = NULL;
+ struct tree_entry *entry;
+
+ if (p_in && parent_in) {
+ p = *p_in;
+ parent = *parent_in;
+ goto do_insert;
+ }
+
+ p = search_start ? &search_start : &root->rb_node;
+ while (*p) {
+ parent = *p;
+ entry = rb_entry(parent, struct tree_entry, rb_node);
+
+ if (offset < entry->start)
+ p = &(*p)->rb_left;
+ else if (offset > entry->end)
+ p = &(*p)->rb_right;
+ else
+ return parent;
+ }
+
+do_insert:
+ rb_link_node(node, parent, p);
+ rb_insert_color(node, root);
+ return NULL;
+}
+
+static struct rb_node *__etree_search(struct extent_io_tree *tree, u64 offset,
+ struct rb_node **prev_ret,
+ struct rb_node **next_ret,
+ struct rb_node ***p_ret,
+ struct rb_node **parent_ret)
+{
+ struct rb_root *root = &tree->state;
+ struct rb_node **n = &root->rb_node;
+ struct rb_node *prev = NULL;
+ struct rb_node *orig_prev = NULL;
+ struct tree_entry *entry;
+ struct tree_entry *prev_entry = NULL;
+
+ while (*n) {
+ prev = *n;
+ entry = rb_entry(prev, struct tree_entry, rb_node);
+ prev_entry = entry;
+
+ if (offset < entry->start)
+ n = &(*n)->rb_left;
+ else if (offset > entry->end)
+ n = &(*n)->rb_right;
+ else
+ return *n;
+ }
+
+ if (p_ret)
+ *p_ret = n;
+ if (parent_ret)
+ *parent_ret = prev;
+
+ if (prev_ret) {
+ orig_prev = prev;
+ while (prev && offset > prev_entry->end) {
+ prev = rb_next(prev);
+ prev_entry = rb_entry(prev, struct tree_entry, rb_node);
+ }
+ *prev_ret = prev;
+ prev = orig_prev;
+ }
+
+ if (next_ret) {
+ prev_entry = rb_entry(prev, struct tree_entry, rb_node);
+ while (prev && offset < prev_entry->start) {
+ prev = rb_prev(prev);
+ prev_entry = rb_entry(prev, struct tree_entry, rb_node);
+ }
+ *next_ret = prev;
+ }
+ return NULL;
+}
+
+static inline struct rb_node *
+tree_search_for_insert(struct extent_io_tree *tree,
+ u64 offset,
+ struct rb_node ***p_ret,
+ struct rb_node **parent_ret)
+{
+ struct rb_node *prev = NULL;
+ struct rb_node *ret;
+
+ ret = __etree_search(tree, offset, &prev, NULL, p_ret, parent_ret);
+ if (!ret)
+ return prev;
+ return ret;
+}
+
+static inline struct rb_node *tree_search(struct extent_io_tree *tree,
+ u64 offset)
+{
+ return tree_search_for_insert(tree, offset, NULL, NULL);
+}
+
+static void merge_cb(struct extent_io_tree *tree, struct extent_state *new,
+ struct extent_state *other)
+{
+ if (tree->ops && tree->ops->merge_extent_hook)
+ tree->ops->merge_extent_hook(tree->private_data, new, other);
+}
+
+/*
+ * utility function to look for merge candidates inside a given range.
+ * Any extents with matching state are merged together into a single
+ * extent in the tree. Extents with EXTENT_IO in their state field
+ * are not merged because the end_io handlers need to be able to do
+ * operations on them without sleeping (or doing allocations/splits).
+ *
+ * This should be called with the tree lock held.
+ */
+static void merge_state(struct extent_io_tree *tree,
+ struct extent_state *state)
+{
+ struct extent_state *other;
+ struct rb_node *other_node;
+
+ if (state->state & (EXTENT_IOBITS | EXTENT_BOUNDARY))
+ return;
+
+ other_node = rb_prev(&state->rb_node);
+ if (other_node) {
+ other = rb_entry(other_node, struct extent_state, rb_node);
+ if (other->end == state->start - 1 &&
+ other->state == state->state) {
+ merge_cb(tree, state, other);
+ state->start = other->start;
+ rb_erase(&other->rb_node, &tree->state);
+ RB_CLEAR_NODE(&other->rb_node);
+ free_extent_state(other);
+ }
+ }
+ other_node = rb_next(&state->rb_node);
+ if (other_node) {
+ other = rb_entry(other_node, struct extent_state, rb_node);
+ if (other->start == state->end + 1 &&
+ other->state == state->state) {
+ merge_cb(tree, state, other);
+ state->end = other->end;
+ rb_erase(&other->rb_node, &tree->state);
+ RB_CLEAR_NODE(&other->rb_node);
+ free_extent_state(other);
+ }
+ }
+}
+
+static void set_state_cb(struct extent_io_tree *tree,
+ struct extent_state *state, unsigned *bits)
+{
+ if (tree->ops && tree->ops->set_bit_hook)
+ tree->ops->set_bit_hook(tree->private_data, state, bits);
+}
+
+static void clear_state_cb(struct extent_io_tree *tree,
+ struct extent_state *state, unsigned *bits)
+{
+ if (tree->ops && tree->ops->clear_bit_hook)
+ tree->ops->clear_bit_hook(tree->private_data, state, bits);
+}
+
+static void set_state_bits(struct extent_io_tree *tree,
+ struct extent_state *state, unsigned *bits,
+ struct extent_changeset *changeset);
+
+/*
+ * insert an extent_state struct into the tree. 'bits' are set on the
+ * struct before it is inserted.
+ *
+ * This may return -EEXIST if the extent is already there, in which case the
+ * state struct is freed.
+ *
+ * The tree lock is not taken internally. This is a utility function and
+ * probably isn't what you want to call (see set/clear_extent_bit).
+ */
+static int insert_state(struct extent_io_tree *tree,
+ struct extent_state *state, u64 start, u64 end,
+ struct rb_node ***p,
+ struct rb_node **parent,
+ unsigned *bits, struct extent_changeset *changeset)
+{
+ struct rb_node *node;
+
+ if (end < start)
+ WARN(1, KERN_ERR "BTRFS: end < start %llu %llu\n",
+ end, start);
+ state->start = start;
+ state->end = end;
+
+ set_state_bits(tree, state, bits, changeset);
+
+ node = tree_insert(&tree->state, NULL, end, &state->rb_node, p, parent);
+ if (node) {
+ struct extent_state *found;
+ found = rb_entry(node, struct extent_state, rb_node);
+ pr_err("BTRFS: found node %llu %llu on insert of %llu %llu\n",
+ found->start, found->end, start, end);
+ return -EEXIST;
+ }
+ merge_state(tree, state);
+ return 0;
+}
+
+static void split_cb(struct extent_io_tree *tree, struct extent_state *orig,
+ u64 split)
+{
+ if (tree->ops && tree->ops->split_extent_hook)
+ tree->ops->split_extent_hook(tree->private_data, orig, split);
+}
+
+/*
+ * split a given extent state struct in two, inserting the preallocated
+ * struct 'prealloc' as the newly created second half. 'split' indicates an
+ * offset inside 'orig' where it should be split.
+ *
+ * Before calling,
+ * the tree has 'orig' at [orig->start, orig->end]. After calling, there
+ * are two extent state structs in the tree:
+ * prealloc: [orig->start, split - 1]
+ * orig: [ split, orig->end ]
+ *
+ * The tree locks are not taken by this function. They need to be held
+ * by the caller.
+ */
+static int split_state(struct extent_io_tree *tree, struct extent_state *orig,
+ struct extent_state *prealloc, u64 split)
+{
+ struct rb_node *node;
+
+ split_cb(tree, orig, split);
+
+ prealloc->start = orig->start;
+ prealloc->end = split - 1;
+ prealloc->state = orig->state;
+ orig->start = split;
+
+ node = tree_insert(&tree->state, &orig->rb_node, prealloc->end,
+ &prealloc->rb_node, NULL, NULL);
+ if (node) {
+ free_extent_state(prealloc);
+ return -EEXIST;
+ }
+ return 0;
+}
+
+static struct extent_state *next_state(struct extent_state *state)
+{
+ struct rb_node *next = rb_next(&state->rb_node);
+ if (next)
+ return rb_entry(next, struct extent_state, rb_node);
+ else
+ return NULL;
+}
+
+/*
+ * utility function to clear some bits in an extent state struct.
+ * it will optionally wake up any one waiting on this state (wake == 1).
+ *
+ * If no bits are set on the state struct after clearing things, the
+ * struct is freed and removed from the tree
+ */
+static struct extent_state *clear_state_bit(struct extent_io_tree *tree,
+ struct extent_state *state,
+ unsigned *bits, int wake,
+ struct extent_changeset *changeset)
+{
+ struct extent_state *next;
+ unsigned bits_to_clear = *bits & ~EXTENT_CTLBITS;
+ int ret;
+
+ if ((bits_to_clear & EXTENT_DIRTY) && (state->state & EXTENT_DIRTY)) {
+ u64 range = state->end - state->start + 1;
+ WARN_ON(range > tree->dirty_bytes);
+ tree->dirty_bytes -= range;
+ }
+ clear_state_cb(tree, state, bits);
+ ret = add_extent_changeset(state, bits_to_clear, changeset, 0);
+ BUG_ON(ret < 0);
+ state->state &= ~bits_to_clear;
+ if (wake)
+ wake_up(&state->wq);
+ if (state->state == 0) {
+ next = next_state(state);
+ if (extent_state_in_tree(state)) {
+ rb_erase(&state->rb_node, &tree->state);
+ RB_CLEAR_NODE(&state->rb_node);
+ free_extent_state(state);
+ } else {
+ WARN_ON(1);
+ }
+ } else {
+ merge_state(tree, state);
+ next = next_state(state);
+ }
+ return next;
+}
+
+static struct extent_state *
+alloc_extent_state_atomic(struct extent_state *prealloc)
+{
+ if (!prealloc)
+ prealloc = alloc_extent_state(GFP_ATOMIC);
+
+ return prealloc;
+}
+
+static void extent_io_tree_panic(struct extent_io_tree *tree, int err)
+{
+ struct inode *inode = tree->private_data;
+
+ btrfs_panic(btrfs_sb(inode->i_sb), err,
+ "locking error: extent tree was modified by another thread while locked");
+}
+
+/*
+ * clear some bits on a range in the tree. This may require splitting
+ * or inserting elements in the tree, so the gfp mask is used to
+ * indicate which allocations or sleeping are allowed.
+ *
+ * pass 'wake' == 1 to kick any sleepers, and 'delete' == 1 to remove
+ * the given range from the tree regardless of state (ie for truncate).
+ *
+ * the range [start, end] is inclusive.
+ *
+ * This takes the tree lock, and returns 0 on success and < 0 on error.
+ */
+int __clear_extent_bit(struct extent_io_tree *tree, u64 start, u64 end,
+ unsigned bits, int wake, int delete,
+ struct extent_state **cached_state,
+ gfp_t mask, struct extent_changeset *changeset)
+{
+ struct extent_state *state;
+ struct extent_state *cached;
+ struct extent_state *prealloc = NULL;
+ struct rb_node *node;
+ u64 last_end;
+ int err;
+ int clear = 0;
+
+ btrfs_debug_check_extent_io_range(tree, start, end);
+
+ if (bits & EXTENT_DELALLOC)
+ bits |= EXTENT_NORESERVE;
+
+ if (delete)
+ bits |= ~EXTENT_CTLBITS;
+ bits |= EXTENT_FIRST_DELALLOC;
+
+ if (bits & (EXTENT_IOBITS | EXTENT_BOUNDARY))
+ clear = 1;
+again:
+ if (!prealloc && gfpflags_allow_blocking(mask)) {
+ /*
+ * Don't care for allocation failure here because we might end
+ * up not needing the pre-allocated extent state at all, which
+ * is the case if we only have in the tree extent states that
+ * cover our input range and don't cover too any other range.
+ * If we end up needing a new extent state we allocate it later.
+ */
+ prealloc = alloc_extent_state(mask);
+ }
+
+ spin_lock(&tree->lock);
+ if (cached_state) {
+ cached = *cached_state;
+
+ if (clear) {
+ *cached_state = NULL;
+ cached_state = NULL;
+ }
+
+ if (cached && extent_state_in_tree(cached) &&
+ cached->start <= start && cached->end > start) {
+ if (clear)
+ refcount_dec(&cached->refs);
+ state = cached;
+ goto hit_next;
+ }
+ if (clear)
+ free_extent_state(cached);
+ }
+ /*
+ * this search will find the extents that end after
+ * our range starts
+ */
+ node = tree_search(tree, start);
+ if (!node)
+ goto out;
+ state = rb_entry(node, struct extent_state, rb_node);
+hit_next:
+ if (state->start > end)
+ goto out;
+ WARN_ON(state->end < start);
+ last_end = state->end;
+
+ /* the state doesn't have the wanted bits, go ahead */
+ if (!(state->state & bits)) {
+ state = next_state(state);
+ goto next;
+ }
+
+ /*
+ * | ---- desired range ---- |
+ * | state | or
+ * | ------------- state -------------- |
+ *
+ * We need to split the extent we found, and may flip
+ * bits on second half.
+ *
+ * If the extent we found extends past our range, we
+ * just split and search again. It'll get split again
+ * the next time though.
+ *
+ * If the extent we found is inside our range, we clear
+ * the desired bit on it.
+ */
+
+ if (state->start < start) {
+ prealloc = alloc_extent_state_atomic(prealloc);
+ BUG_ON(!prealloc);
+ err = split_state(tree, state, prealloc, start);
+ if (err)
+ extent_io_tree_panic(tree, err);
+
+ prealloc = NULL;
+ if (err)
+ goto out;
+ if (state->end <= end) {
+ state = clear_state_bit(tree, state, &bits, wake,
+ changeset);
+ goto next;
+ }
+ goto search_again;
+ }
+ /*
+ * | ---- desired range ---- |
+ * | state |
+ * We need to split the extent, and clear the bit
+ * on the first half
+ */
+ if (state->start <= end && state->end > end) {
+ prealloc = alloc_extent_state_atomic(prealloc);
+ BUG_ON(!prealloc);
+ err = split_state(tree, state, prealloc, end + 1);
+ if (err)
+ extent_io_tree_panic(tree, err);
+
+ if (wake)
+ wake_up(&state->wq);
+
+ clear_state_bit(tree, prealloc, &bits, wake, changeset);
+
+ prealloc = NULL;
+ goto out;
+ }
+
+ state = clear_state_bit(tree, state, &bits, wake, changeset);
+next:
+ if (last_end == (u64)-1)
+ goto out;
+ start = last_end + 1;
+ if (start <= end && state && !need_resched())
+ goto hit_next;
+
+search_again:
+ if (start > end)
+ goto out;
+ spin_unlock(&tree->lock);
+ if (gfpflags_allow_blocking(mask))
+ cond_resched();
+ goto again;
+
+out:
+ spin_unlock(&tree->lock);
+ if (prealloc)
+ free_extent_state(prealloc);
+
+ return 0;
+
+}
+
+static void wait_on_state(struct extent_io_tree *tree,
+ struct extent_state *state)
+ __releases(tree->lock)
+ __acquires(tree->lock)
+{
+ DEFINE_WAIT(wait);
+ prepare_to_wait(&state->wq, &wait, TASK_UNINTERRUPTIBLE);
+ spin_unlock(&tree->lock);
+ schedule();
+ spin_lock(&tree->lock);
+ finish_wait(&state->wq, &wait);
+}
+
+/*
+ * waits for one or more bits to clear on a range in the state tree.
+ * The range [start, end] is inclusive.
+ * The tree lock is taken by this function
+ */
+static void wait_extent_bit(struct extent_io_tree *tree, u64 start, u64 end,
+ unsigned long bits)
+{
+ struct extent_state *state;
+ struct rb_node *node;
+
+ btrfs_debug_check_extent_io_range(tree, start, end);
+
+ spin_lock(&tree->lock);
+again:
+ while (1) {
+ /*
+ * this search will find all the extents that end after
+ * our range starts
+ */
+ node = tree_search(tree, start);
+process_node:
+ if (!node)
+ break;
+
+ state = rb_entry(node, struct extent_state, rb_node);
+
+ if (state->start > end)
+ goto out;
+
+ if (state->state & bits) {
+ start = state->start;
+ refcount_inc(&state->refs);
+ wait_on_state(tree, state);
+ free_extent_state(state);
+ goto again;
+ }
+ start = state->end + 1;
+
+ if (start > end)
+ break;
+
+ if (!cond_resched_lock(&tree->lock)) {
+ node = rb_next(node);
+ goto process_node;
+ }
+ }
+out:
+ spin_unlock(&tree->lock);
+}
+
+static void set_state_bits(struct extent_io_tree *tree,
+ struct extent_state *state,
+ unsigned *bits, struct extent_changeset *changeset)
+{
+ unsigned bits_to_set = *bits & ~EXTENT_CTLBITS;
+ int ret;
+
+ set_state_cb(tree, state, bits);
+ if ((bits_to_set & EXTENT_DIRTY) && !(state->state & EXTENT_DIRTY)) {
+ u64 range = state->end - state->start + 1;
+ tree->dirty_bytes += range;
+ }
+ ret = add_extent_changeset(state, bits_to_set, changeset, 1);
+ BUG_ON(ret < 0);
+ state->state |= bits_to_set;
+}
+
+static void cache_state_if_flags(struct extent_state *state,
+ struct extent_state **cached_ptr,
+ unsigned flags)
+{
+ if (cached_ptr && !(*cached_ptr)) {
+ if (!flags || (state->state & flags)) {
+ *cached_ptr = state;
+ refcount_inc(&state->refs);
+ }
+ }
+}
+
+static void cache_state(struct extent_state *state,
+ struct extent_state **cached_ptr)
+{
+ return cache_state_if_flags(state, cached_ptr,
+ EXTENT_IOBITS | EXTENT_BOUNDARY);
+}
+
+/*
+ * set some bits on a range in the tree. This may require allocations or
+ * sleeping, so the gfp mask is used to indicate what is allowed.
+ *
+ * If any of the exclusive bits are set, this will fail with -EEXIST if some
+ * part of the range already has the desired bits set. The start of the
+ * existing range is returned in failed_start in this case.
+ *
+ * [start, end] is inclusive This takes the tree lock.
+ */
+
+static int __must_check
+__set_extent_bit(struct extent_io_tree *tree, u64 start, u64 end,
+ unsigned bits, unsigned exclusive_bits,
+ u64 *failed_start, struct extent_state **cached_state,
+ gfp_t mask, struct extent_changeset *changeset)
+{
+ struct extent_state *state;
+ struct extent_state *prealloc = NULL;
+ struct rb_node *node;
+ struct rb_node **p;
+ struct rb_node *parent;
+ int err = 0;
+ u64 last_start;
+ u64 last_end;
+
+ btrfs_debug_check_extent_io_range(tree, start, end);
+
+ bits |= EXTENT_FIRST_DELALLOC;
+again:
+ if (!prealloc && gfpflags_allow_blocking(mask)) {
+ /*
+ * Don't care for allocation failure here because we might end
+ * up not needing the pre-allocated extent state at all, which
+ * is the case if we only have in the tree extent states that
+ * cover our input range and don't cover too any other range.
+ * If we end up needing a new extent state we allocate it later.
+ */
+ prealloc = alloc_extent_state(mask);
+ }
+
+ spin_lock(&tree->lock);
+ if (cached_state && *cached_state) {
+ state = *cached_state;
+ if (state->start <= start && state->end > start &&
+ extent_state_in_tree(state)) {
+ node = &state->rb_node;
+ goto hit_next;
+ }
+ }
+ /*
+ * this search will find all the extents that end after
+ * our range starts.
+ */
+ node = tree_search_for_insert(tree, start, &p, &parent);
+ if (!node) {
+ prealloc = alloc_extent_state_atomic(prealloc);
+ BUG_ON(!prealloc);
+ err = insert_state(tree, prealloc, start, end,
+ &p, &parent, &bits, changeset);
+ if (err)
+ extent_io_tree_panic(tree, err);
+
+ cache_state(prealloc, cached_state);
+ prealloc = NULL;
+ goto out;
+ }
+ state = rb_entry(node, struct extent_state, rb_node);
+hit_next:
+ last_start = state->start;
+ last_end = state->end;
+
+ /*
+ * | ---- desired range ---- |
+ * | state |
+ *
+ * Just lock what we found and keep going
+ */
+ if (state->start == start && state->end <= end) {
+ if (state->state & exclusive_bits) {
+ *failed_start = state->start;
+ err = -EEXIST;
+ goto out;
+ }
+
+ set_state_bits(tree, state, &bits, changeset);
+ cache_state(state, cached_state);
+ merge_state(tree, state);
+ if (last_end == (u64)-1)
+ goto out;
+ start = last_end + 1;
+ state = next_state(state);
+ if (start < end && state && state->start == start &&
+ !need_resched())
+ goto hit_next;
+ goto search_again;
+ }
+
+ /*
+ * | ---- desired range ---- |
+ * | state |
+ * or
+ * | ------------- state -------------- |
+ *
+ * We need to split the extent we found, and may flip bits on
+ * second half.
+ *
+ * If the extent we found extends past our
+ * range, we just split and search again. It'll get split
+ * again the next time though.
+ *
+ * If the extent we found is inside our range, we set the
+ * desired bit on it.
+ */
+ if (state->start < start) {
+ if (state->state & exclusive_bits) {
+ *failed_start = start;
+ err = -EEXIST;
+ goto out;
+ }
+
+ prealloc = alloc_extent_state_atomic(prealloc);
+ BUG_ON(!prealloc);
+ err = split_state(tree, state, prealloc, start);
+ if (err)
+ extent_io_tree_panic(tree, err);
+
+ prealloc = NULL;
+ if (err)
+ goto out;
+ if (state->end <= end) {
+ set_state_bits(tree, state, &bits, changeset);
+ cache_state(state, cached_state);
+ merge_state(tree, state);
+ if (last_end == (u64)-1)
+ goto out;
+ start = last_end + 1;
+ state = next_state(state);
+ if (start < end && state && state->start == start &&
+ !need_resched())
+ goto hit_next;
+ }
+ goto search_again;
+ }
+ /*
+ * | ---- desired range ---- |
+ * | state | or | state |
+ *
+ * There's a hole, we need to insert something in it and
+ * ignore the extent we found.
+ */
+ if (state->start > start) {
+ u64 this_end;
+ if (end < last_start)
+ this_end = end;
+ else
+ this_end = last_start - 1;
+
+ prealloc = alloc_extent_state_atomic(prealloc);
+ BUG_ON(!prealloc);
+
+ /*
+ * Avoid to free 'prealloc' if it can be merged with
+ * the later extent.
+ */
+ err = insert_state(tree, prealloc, start, this_end,
+ NULL, NULL, &bits, changeset);
+ if (err)
+ extent_io_tree_panic(tree, err);
+
+ cache_state(prealloc, cached_state);
+ prealloc = NULL;
+ start = this_end + 1;
+ goto search_again;
+ }
+ /*
+ * | ---- desired range ---- |
+ * | state |
+ * We need to split the extent, and set the bit
+ * on the first half
+ */
+ if (state->start <= end && state->end > end) {
+ if (state->state & exclusive_bits) {
+ *failed_start = start;
+ err = -EEXIST;
+ goto out;
+ }
+
+ prealloc = alloc_extent_state_atomic(prealloc);
+ BUG_ON(!prealloc);
+ err = split_state(tree, state, prealloc, end + 1);
+ if (err)
+ extent_io_tree_panic(tree, err);
+
+ set_state_bits(tree, prealloc, &bits, changeset);
+ cache_state(prealloc, cached_state);
+ merge_state(tree, prealloc);
+ prealloc = NULL;
+ goto out;
+ }
+
+search_again:
+ if (start > end)
+ goto out;
+ spin_unlock(&tree->lock);
+ if (gfpflags_allow_blocking(mask))
+ cond_resched();
+ goto again;
+
+out:
+ spin_unlock(&tree->lock);
+ if (prealloc)
+ free_extent_state(prealloc);
+
+ return err;
+
+}
+
+int set_extent_bit(struct extent_io_tree *tree, u64 start, u64 end,
+ unsigned bits, u64 * failed_start,
+ struct extent_state **cached_state, gfp_t mask)
+{
+ return __set_extent_bit(tree, start, end, bits, 0, failed_start,
+ cached_state, mask, NULL);
+}
+
+
+/**
+ * convert_extent_bit - convert all bits in a given range from one bit to
+ * another
+ * @tree: the io tree to search
+ * @start: the start offset in bytes
+ * @end: the end offset in bytes (inclusive)
+ * @bits: the bits to set in this range
+ * @clear_bits: the bits to clear in this range
+ * @cached_state: state that we're going to cache
+ *
+ * This will go through and set bits for the given range. If any states exist
+ * already in this range they are set with the given bit and cleared of the
+ * clear_bits. This is only meant to be used by things that are mergeable, ie
+ * converting from say DELALLOC to DIRTY. This is not meant to be used with
+ * boundary bits like LOCK.
+ *
+ * All allocations are done with GFP_NOFS.
+ */
+int convert_extent_bit(struct extent_io_tree *tree, u64 start, u64 end,
+ unsigned bits, unsigned clear_bits,
+ struct extent_state **cached_state)
+{
+ struct extent_state *state;
+ struct extent_state *prealloc = NULL;
+ struct rb_node *node;
+ struct rb_node **p;
+ struct rb_node *parent;
+ int err = 0;
+ u64 last_start;
+ u64 last_end;
+ bool first_iteration = true;
+
+ btrfs_debug_check_extent_io_range(tree, start, end);
+
+again:
+ if (!prealloc) {
+ /*
+ * Best effort, don't worry if extent state allocation fails
+ * here for the first iteration. We might have a cached state
+ * that matches exactly the target range, in which case no
+ * extent state allocations are needed. We'll only know this
+ * after locking the tree.
+ */
+ prealloc = alloc_extent_state(GFP_NOFS);
+ if (!prealloc && !first_iteration)
+ return -ENOMEM;
+ }
+
+ spin_lock(&tree->lock);
+ if (cached_state && *cached_state) {
+ state = *cached_state;
+ if (state->start <= start && state->end > start &&
+ extent_state_in_tree(state)) {
+ node = &state->rb_node;
+ goto hit_next;
+ }
+ }
+
+ /*
+ * this search will find all the extents that end after
+ * our range starts.
+ */
+ node = tree_search_for_insert(tree, start, &p, &parent);
+ if (!node) {
+ prealloc = alloc_extent_state_atomic(prealloc);
+ if (!prealloc) {
+ err = -ENOMEM;
+ goto out;
+ }
+ err = insert_state(tree, prealloc, start, end,
+ &p, &parent, &bits, NULL);
+ if (err)
+ extent_io_tree_panic(tree, err);
+ cache_state(prealloc, cached_state);
+ prealloc = NULL;
+ goto out;
+ }
+ state = rb_entry(node, struct extent_state, rb_node);
+hit_next:
+ last_start = state->start;
+ last_end = state->end;
+
+ /*
+ * | ---- desired range ---- |
+ * | state |
+ *
+ * Just lock what we found and keep going
+ */
+ if (state->start == start && state->end <= end) {
+ set_state_bits(tree, state, &bits, NULL);
+ cache_state(state, cached_state);
+ state = clear_state_bit(tree, state, &clear_bits, 0, NULL);
+ if (last_end == (u64)-1)
+ goto out;
+ start = last_end + 1;
+ if (start < end && state && state->start == start &&
+ !need_resched())
+ goto hit_next;
+ goto search_again;
+ }
+
+ /*
+ * | ---- desired range ---- |
+ * | state |
+ * or
+ * | ------------- state -------------- |
+ *
+ * We need to split the extent we found, and may flip bits on
+ * second half.
+ *
+ * If the extent we found extends past our
+ * range, we just split and search again. It'll get split
+ * again the next time though.
+ *
+ * If the extent we found is inside our range, we set the
+ * desired bit on it.
+ */
+ if (state->start < start) {
+ prealloc = alloc_extent_state_atomic(prealloc);
+ if (!prealloc) {
+ err = -ENOMEM;
+ goto out;
+ }
+ err = split_state(tree, state, prealloc, start);
+ if (err)
+ extent_io_tree_panic(tree, err);
+ prealloc = NULL;
+ if (err)
+ goto out;
+ if (state->end <= end) {
+ set_state_bits(tree, state, &bits, NULL);
+ cache_state(state, cached_state);
+ state = clear_state_bit(tree, state, &clear_bits, 0,
+ NULL);
+ if (last_end == (u64)-1)
+ goto out;
+ start = last_end + 1;
+ if (start < end && state && state->start == start &&
+ !need_resched())
+ goto hit_next;
+ }
+ goto search_again;
+ }
+ /*
+ * | ---- desired range ---- |
+ * | state | or | state |
+ *
+ * There's a hole, we need to insert something in it and
+ * ignore the extent we found.
+ */
+ if (state->start > start) {
+ u64 this_end;
+ if (end < last_start)
+ this_end = end;
+ else
+ this_end = last_start - 1;
+
+ prealloc = alloc_extent_state_atomic(prealloc);
+ if (!prealloc) {
+ err = -ENOMEM;
+ goto out;
+ }
+
+ /*
+ * Avoid to free 'prealloc' if it can be merged with
+ * the later extent.
+ */
+ err = insert_state(tree, prealloc, start, this_end,
+ NULL, NULL, &bits, NULL);
+ if (err)
+ extent_io_tree_panic(tree, err);
+ cache_state(prealloc, cached_state);
+ prealloc = NULL;
+ start = this_end + 1;
+ goto search_again;
+ }
+ /*
+ * | ---- desired range ---- |
+ * | state |
+ * We need to split the extent, and set the bit
+ * on the first half
+ */
+ if (state->start <= end && state->end > end) {
+ prealloc = alloc_extent_state_atomic(prealloc);
+ if (!prealloc) {
+ err = -ENOMEM;
+ goto out;
+ }
+
+ err = split_state(tree, state, prealloc, end + 1);
+ if (err)
+ extent_io_tree_panic(tree, err);
+
+ set_state_bits(tree, prealloc, &bits, NULL);
+ cache_state(prealloc, cached_state);
+ clear_state_bit(tree, prealloc, &clear_bits, 0, NULL);
+ prealloc = NULL;
+ goto out;
+ }
+
+search_again:
+ if (start > end)
+ goto out;
+ spin_unlock(&tree->lock);
+ cond_resched();
+ first_iteration = false;
+ goto again;
+
+out:
+ spin_unlock(&tree->lock);
+ if (prealloc)
+ free_extent_state(prealloc);
+
+ return err;
+}
+
+/* wrappers around set/clear extent bit */
+int set_record_extent_bits(struct extent_io_tree *tree, u64 start, u64 end,
+ unsigned bits, struct extent_changeset *changeset)
+{
+ /*
+ * We don't support EXTENT_LOCKED yet, as current changeset will
+ * record any bits changed, so for EXTENT_LOCKED case, it will
+ * either fail with -EEXIST or changeset will record the whole
+ * range.
+ */
+ BUG_ON(bits & EXTENT_LOCKED);
+
+ return __set_extent_bit(tree, start, end, bits, 0, NULL, NULL, GFP_NOFS,
+ changeset);
+}
+
+int clear_extent_bit(struct extent_io_tree *tree, u64 start, u64 end,
+ unsigned bits, int wake, int delete,
+ struct extent_state **cached)
+{
+ return __clear_extent_bit(tree, start, end, bits, wake, delete,
+ cached, GFP_NOFS, NULL);
+}
+
+int clear_record_extent_bits(struct extent_io_tree *tree, u64 start, u64 end,
+ unsigned bits, struct extent_changeset *changeset)
+{
+ /*
+ * Don't support EXTENT_LOCKED case, same reason as
+ * set_record_extent_bits().
+ */
+ BUG_ON(bits & EXTENT_LOCKED);
+
+ return __clear_extent_bit(tree, start, end, bits, 0, 0, NULL, GFP_NOFS,
+ changeset);
+}
+
+/*
+ * either insert or lock state struct between start and end use mask to tell
+ * us if waiting is desired.
+ */
+int lock_extent_bits(struct extent_io_tree *tree, u64 start, u64 end,
+ struct extent_state **cached_state)
+{
+ int err;
+ u64 failed_start;
+
+ while (1) {
+ err = __set_extent_bit(tree, start, end, EXTENT_LOCKED,
+ EXTENT_LOCKED, &failed_start,
+ cached_state, GFP_NOFS, NULL);
+ if (err == -EEXIST) {
+ wait_extent_bit(tree, failed_start, end, EXTENT_LOCKED);
+ start = failed_start;
+ } else
+ break;
+ WARN_ON(start > end);
+ }
+ return err;
+}
+
+int try_lock_extent(struct extent_io_tree *tree, u64 start, u64 end)
+{
+ int err;
+ u64 failed_start;
+
+ err = __set_extent_bit(tree, start, end, EXTENT_LOCKED, EXTENT_LOCKED,
+ &failed_start, NULL, GFP_NOFS, NULL);
+ if (err == -EEXIST) {
+ if (failed_start > start)
+ clear_extent_bit(tree, start, failed_start - 1,
+ EXTENT_LOCKED, 1, 0, NULL);
+ return 0;
+ }
+ return 1;
+}
+
+void extent_range_clear_dirty_for_io(struct inode *inode, u64 start, u64 end)
+{
+ unsigned long index = start >> PAGE_SHIFT;
+ unsigned long end_index = end >> PAGE_SHIFT;
+ struct page *page;
+
+ while (index <= end_index) {
+ page = find_get_page(inode->i_mapping, index);
+ BUG_ON(!page); /* Pages should be in the extent_io_tree */
+ clear_page_dirty_for_io(page);
+ put_page(page);
+ index++;
+ }
+}
+
+void extent_range_redirty_for_io(struct inode *inode, u64 start, u64 end)
+{
+ unsigned long index = start >> PAGE_SHIFT;
+ unsigned long end_index = end >> PAGE_SHIFT;
+ struct page *page;
+
+ while (index <= end_index) {
+ page = find_get_page(inode->i_mapping, index);
+ BUG_ON(!page); /* Pages should be in the extent_io_tree */
+ __set_page_dirty_nobuffers(page);
+ account_page_redirty(page);
+ put_page(page);
+ index++;
+ }
+}
+
+/* find the first state struct with 'bits' set after 'start', and
+ * return it. tree->lock must be held. NULL will returned if
+ * nothing was found after 'start'
+ */
+static struct extent_state *
+find_first_extent_bit_state(struct extent_io_tree *tree,
+ u64 start, unsigned bits)
+{
+ struct rb_node *node;
+ struct extent_state *state;
+
+ /*
+ * this search will find all the extents that end after
+ * our range starts.
+ */
+ node = tree_search(tree, start);
+ if (!node)
+ goto out;
+
+ while (1) {
+ state = rb_entry(node, struct extent_state, rb_node);
+ if (state->end >= start && (state->state & bits))
+ return state;
+
+ node = rb_next(node);
+ if (!node)
+ break;
+ }
+out:
+ return NULL;
+}
+
+/*
+ * find the first offset in the io tree with 'bits' set. zero is
+ * returned if we find something, and *start_ret and *end_ret are
+ * set to reflect the state struct that was found.
+ *
+ * If nothing was found, 1 is returned. If found something, return 0.
+ */
+int find_first_extent_bit(struct extent_io_tree *tree, u64 start,
+ u64 *start_ret, u64 *end_ret, unsigned bits,
+ struct extent_state **cached_state)
+{
+ struct extent_state *state;
+ struct rb_node *n;
+ int ret = 1;
+
+ spin_lock(&tree->lock);
+ if (cached_state && *cached_state) {
+ state = *cached_state;
+ if (state->end == start - 1 && extent_state_in_tree(state)) {
+ n = rb_next(&state->rb_node);
+ while (n) {
+ state = rb_entry(n, struct extent_state,
+ rb_node);
+ if (state->state & bits)
+ goto got_it;
+ n = rb_next(n);
+ }
+ free_extent_state(*cached_state);
+ *cached_state = NULL;
+ goto out;
+ }
+ free_extent_state(*cached_state);
+ *cached_state = NULL;
+ }
+
+ state = find_first_extent_bit_state(tree, start, bits);
+got_it:
+ if (state) {
+ cache_state_if_flags(state, cached_state, 0);
+ *start_ret = state->start;
+ *end_ret = state->end;
+ ret = 0;
+ }
+out:
+ spin_unlock(&tree->lock);
+ return ret;
+}
+
+/*
+ * find a contiguous range of bytes in the file marked as delalloc, not
+ * more than 'max_bytes'. start and end are used to return the range,
+ *
+ * 1 is returned if we find something, 0 if nothing was in the tree
+ */
+static noinline u64 find_delalloc_range(struct extent_io_tree *tree,
+ u64 *start, u64 *end, u64 max_bytes,
+ struct extent_state **cached_state)
+{
+ struct rb_node *node;
+ struct extent_state *state;
+ u64 cur_start = *start;
+ u64 found = 0;
+ u64 total_bytes = 0;
+
+ spin_lock(&tree->lock);
+
+ /*
+ * this search will find all the extents that end after
+ * our range starts.
+ */
+ node = tree_search(tree, cur_start);
+ if (!node) {
+ if (!found)
+ *end = (u64)-1;
+ goto out;
+ }
+
+ while (1) {
+ state = rb_entry(node, struct extent_state, rb_node);
+ if (found && (state->start != cur_start ||
+ (state->state & EXTENT_BOUNDARY))) {
+ goto out;
+ }
+ if (!(state->state & EXTENT_DELALLOC)) {
+ if (!found)
+ *end = state->end;
+ goto out;
+ }
+ if (!found) {
+ *start = state->start;
+ *cached_state = state;
+ refcount_inc(&state->refs);
+ }
+ found++;
+ *end = state->end;
+ cur_start = state->end + 1;
+ node = rb_next(node);
+ total_bytes += state->end - state->start + 1;
+ if (total_bytes >= max_bytes)
+ break;
+ if (!node)
+ break;
+ }
+out:
+ spin_unlock(&tree->lock);
+ return found;
+}
+
+static int __process_pages_contig(struct address_space *mapping,
+ struct page *locked_page,
+ pgoff_t start_index, pgoff_t end_index,
+ unsigned long page_ops, pgoff_t *index_ret);
+
+static noinline void __unlock_for_delalloc(struct inode *inode,
+ struct page *locked_page,
+ u64 start, u64 end)
+{
+ unsigned long index = start >> PAGE_SHIFT;
+ unsigned long end_index = end >> PAGE_SHIFT;
+
+ ASSERT(locked_page);
+ if (index == locked_page->index && end_index == index)
+ return;
+
+ __process_pages_contig(inode->i_mapping, locked_page, index, end_index,
+ PAGE_UNLOCK, NULL);
+}
+
+static noinline int lock_delalloc_pages(struct inode *inode,
+ struct page *locked_page,
+ u64 delalloc_start,
+ u64 delalloc_end)
+{
+ unsigned long index = delalloc_start >> PAGE_SHIFT;
+ unsigned long index_ret = index;
+ unsigned long end_index = delalloc_end >> PAGE_SHIFT;
+ int ret;
+
+ ASSERT(locked_page);
+ if (index == locked_page->index && index == end_index)
+ return 0;
+
+ ret = __process_pages_contig(inode->i_mapping, locked_page, index,
+ end_index, PAGE_LOCK, &index_ret);
+ if (ret == -EAGAIN)
+ __unlock_for_delalloc(inode, locked_page, delalloc_start,
+ (u64)index_ret << PAGE_SHIFT);
+ return ret;
+}
+
+/*
+ * find a contiguous range of bytes in the file marked as delalloc, not
+ * more than 'max_bytes'. start and end are used to return the range,
+ *
+ * 1 is returned if we find something, 0 if nothing was in the tree
+ */
+STATIC u64 find_lock_delalloc_range(struct inode *inode,
+ struct extent_io_tree *tree,
+ struct page *locked_page, u64 *start,
+ u64 *end, u64 max_bytes)
+{
+ u64 delalloc_start;
+ u64 delalloc_end;
+ u64 found;
+ struct extent_state *cached_state = NULL;
+ int ret;
+ int loops = 0;
+
+again:
+ /* step one, find a bunch of delalloc bytes starting at start */
+ delalloc_start = *start;
+ delalloc_end = 0;
+ found = find_delalloc_range(tree, &delalloc_start, &delalloc_end,
+ max_bytes, &cached_state);
+ if (!found || delalloc_end <= *start) {
+ *start = delalloc_start;
+ *end = delalloc_end;
+ free_extent_state(cached_state);
+ return 0;
+ }
+
+ /*
+ * start comes from the offset of locked_page. We have to lock
+ * pages in order, so we can't process delalloc bytes before
+ * locked_page
+ */
+ if (delalloc_start < *start)
+ delalloc_start = *start;
+
+ /*
+ * make sure to limit the number of pages we try to lock down
+ */
+ if (delalloc_end + 1 - delalloc_start > max_bytes)
+ delalloc_end = delalloc_start + max_bytes - 1;
+
+ /* step two, lock all the pages after the page that has start */
+ ret = lock_delalloc_pages(inode, locked_page,
+ delalloc_start, delalloc_end);
+ if (ret == -EAGAIN) {
+ /* some of the pages are gone, lets avoid looping by
+ * shortening the size of the delalloc range we're searching
+ */
+ free_extent_state(cached_state);
+ cached_state = NULL;
+ if (!loops) {
+ max_bytes = PAGE_SIZE;
+ loops = 1;
+ goto again;
+ } else {
+ found = 0;
+ goto out_failed;
+ }
+ }
+ BUG_ON(ret); /* Only valid values are 0 and -EAGAIN */
+
+ /* step three, lock the state bits for the whole range */
+ lock_extent_bits(tree, delalloc_start, delalloc_end, &cached_state);
+
+ /* then test to make sure it is all still delalloc */
+ ret = test_range_bit(tree, delalloc_start, delalloc_end,
+ EXTENT_DELALLOC, 1, cached_state);
+ if (!ret) {
+ unlock_extent_cached(tree, delalloc_start, delalloc_end,
+ &cached_state);
+ __unlock_for_delalloc(inode, locked_page,
+ delalloc_start, delalloc_end);
+ cond_resched();
+ goto again;
+ }
+ free_extent_state(cached_state);
+ *start = delalloc_start;
+ *end = delalloc_end;
+out_failed:
+ return found;
+}
+
+static int __process_pages_contig(struct address_space *mapping,
+ struct page *locked_page,
+ pgoff_t start_index, pgoff_t end_index,
+ unsigned long page_ops, pgoff_t *index_ret)
+{
+ unsigned long nr_pages = end_index - start_index + 1;
+ unsigned long pages_locked = 0;
+ pgoff_t index = start_index;
+ struct page *pages[16];
+ unsigned ret;
+ int err = 0;
+ int i;
+
+ if (page_ops & PAGE_LOCK) {
+ ASSERT(page_ops == PAGE_LOCK);
+ ASSERT(index_ret && *index_ret == start_index);
+ }
+
+ if ((page_ops & PAGE_SET_ERROR) && nr_pages > 0)
+ mapping_set_error(mapping, -EIO);
+
+ while (nr_pages > 0) {
+ ret = find_get_pages_contig(mapping, index,
+ min_t(unsigned long,
+ nr_pages, ARRAY_SIZE(pages)), pages);
+ if (ret == 0) {
+ /*
+ * Only if we're going to lock these pages,
+ * can we find nothing at @index.
+ */
+ ASSERT(page_ops & PAGE_LOCK);
+ err = -EAGAIN;
+ goto out;
+ }
+
+ for (i = 0; i < ret; i++) {
+ if (page_ops & PAGE_SET_PRIVATE2)
+ SetPagePrivate2(pages[i]);
+
+ if (pages[i] == locked_page) {
+ put_page(pages[i]);
+ pages_locked++;
+ continue;
+ }
+ if (page_ops & PAGE_CLEAR_DIRTY)
+ clear_page_dirty_for_io(pages[i]);
+ if (page_ops & PAGE_SET_WRITEBACK)
+ set_page_writeback(pages[i]);
+ if (page_ops & PAGE_SET_ERROR)
+ SetPageError(pages[i]);
+ if (page_ops & PAGE_END_WRITEBACK)
+ end_page_writeback(pages[i]);
+ if (page_ops & PAGE_UNLOCK)
+ unlock_page(pages[i]);
+ if (page_ops & PAGE_LOCK) {
+ lock_page(pages[i]);
+ if (!PageDirty(pages[i]) ||
+ pages[i]->mapping != mapping) {
+ unlock_page(pages[i]);
+ put_page(pages[i]);
+ err = -EAGAIN;
+ goto out;
+ }
+ }
+ put_page(pages[i]);
+ pages_locked++;
+ }
+ nr_pages -= ret;
+ index += ret;
+ cond_resched();
+ }
+out:
+ if (err && index_ret)
+ *index_ret = start_index + pages_locked - 1;
+ return err;
+}
+
+void extent_clear_unlock_delalloc(struct inode *inode, u64 start, u64 end,
+ u64 delalloc_end, struct page *locked_page,
+ unsigned clear_bits,
+ unsigned long page_ops)
+{
+ clear_extent_bit(&BTRFS_I(inode)->io_tree, start, end, clear_bits, 1, 0,
+ NULL);
+
+ __process_pages_contig(inode->i_mapping, locked_page,
+ start >> PAGE_SHIFT, end >> PAGE_SHIFT,
+ page_ops, NULL);
+}
+
+/*
+ * count the number of bytes in the tree that have a given bit(s)
+ * set. This can be fairly slow, except for EXTENT_DIRTY which is
+ * cached. The total number found is returned.
+ */
+u64 count_range_bits(struct extent_io_tree *tree,
+ u64 *start, u64 search_end, u64 max_bytes,
+ unsigned bits, int contig)
+{
+ struct rb_node *node;
+ struct extent_state *state;
+ u64 cur_start = *start;
+ u64 total_bytes = 0;
+ u64 last = 0;
+ int found = 0;
+
+ if (WARN_ON(search_end <= cur_start))
+ return 0;
+
+ spin_lock(&tree->lock);
+ if (cur_start == 0 && bits == EXTENT_DIRTY) {
+ total_bytes = tree->dirty_bytes;
+ goto out;
+ }
+ /*
+ * this search will find all the extents that end after
+ * our range starts.
+ */
+ node = tree_search(tree, cur_start);
+ if (!node)
+ goto out;
+
+ while (1) {
+ state = rb_entry(node, struct extent_state, rb_node);
+ if (state->start > search_end)
+ break;
+ if (contig && found && state->start > last + 1)
+ break;
+ if (state->end >= cur_start && (state->state & bits) == bits) {
+ total_bytes += min(search_end, state->end) + 1 -
+ max(cur_start, state->start);
+ if (total_bytes >= max_bytes)
+ break;
+ if (!found) {
+ *start = max(cur_start, state->start);
+ found = 1;
+ }
+ last = state->end;
+ } else if (contig && found) {
+ break;
+ }
+ node = rb_next(node);
+ if (!node)
+ break;
+ }
+out:
+ spin_unlock(&tree->lock);
+ return total_bytes;
+}
+
+/*
+ * set the private field for a given byte offset in the tree. If there isn't
+ * an extent_state there already, this does nothing.
+ */
+static noinline int set_state_failrec(struct extent_io_tree *tree, u64 start,
+ struct io_failure_record *failrec)
+{
+ struct rb_node *node;
+ struct extent_state *state;
+ int ret = 0;
+
+ spin_lock(&tree->lock);
+ /*
+ * this search will find all the extents that end after
+ * our range starts.
+ */
+ node = tree_search(tree, start);
+ if (!node) {
+ ret = -ENOENT;
+ goto out;
+ }
+ state = rb_entry(node, struct extent_state, rb_node);
+ if (state->start != start) {
+ ret = -ENOENT;
+ goto out;
+ }
+ state->failrec = failrec;
+out:
+ spin_unlock(&tree->lock);
+ return ret;
+}
+
+static noinline int get_state_failrec(struct extent_io_tree *tree, u64 start,
+ struct io_failure_record **failrec)
+{
+ struct rb_node *node;
+ struct extent_state *state;
+ int ret = 0;
+
+ spin_lock(&tree->lock);
+ /*
+ * this search will find all the extents that end after
+ * our range starts.
+ */
+ node = tree_search(tree, start);
+ if (!node) {
+ ret = -ENOENT;
+ goto out;
+ }
+ state = rb_entry(node, struct extent_state, rb_node);
+ if (state->start != start) {
+ ret = -ENOENT;
+ goto out;
+ }
+ *failrec = state->failrec;
+out:
+ spin_unlock(&tree->lock);
+ return ret;
+}
+
+/*
+ * searches a range in the state tree for a given mask.
+ * If 'filled' == 1, this returns 1 only if every extent in the tree
+ * has the bits set. Otherwise, 1 is returned if any bit in the
+ * range is found set.
+ */
+int test_range_bit(struct extent_io_tree *tree, u64 start, u64 end,
+ unsigned bits, int filled, struct extent_state *cached)
+{
+ struct extent_state *state = NULL;
+ struct rb_node *node;
+ int bitset = 0;
+
+ spin_lock(&tree->lock);
+ if (cached && extent_state_in_tree(cached) && cached->start <= start &&
+ cached->end > start)
+ node = &cached->rb_node;
+ else
+ node = tree_search(tree, start);
+ while (node && start <= end) {
+ state = rb_entry(node, struct extent_state, rb_node);
+
+ if (filled && state->start > start) {
+ bitset = 0;
+ break;
+ }
+
+ if (state->start > end)
+ break;
+
+ if (state->state & bits) {
+ bitset = 1;
+ if (!filled)
+ break;
+ } else if (filled) {
+ bitset = 0;
+ break;
+ }
+
+ if (state->end == (u64)-1)
+ break;
+
+ start = state->end + 1;
+ if (start > end)
+ break;
+ node = rb_next(node);
+ if (!node) {
+ if (filled)
+ bitset = 0;
+ break;
+ }
+ }
+ spin_unlock(&tree->lock);
+ return bitset;
+}
+
+/*
+ * helper function to set a given page up to date if all the
+ * extents in the tree for that page are up to date
+ */
+static void check_page_uptodate(struct extent_io_tree *tree, struct page *page)
+{
+ u64 start = page_offset(page);
+ u64 end = start + PAGE_SIZE - 1;
+ if (test_range_bit(tree, start, end, EXTENT_UPTODATE, 1, NULL))
+ SetPageUptodate(page);
+}
+
+int free_io_failure(struct extent_io_tree *failure_tree,
+ struct extent_io_tree *io_tree,
+ struct io_failure_record *rec)
+{
+ int ret;
+ int err = 0;
+
+ set_state_failrec(failure_tree, rec->start, NULL);
+ ret = clear_extent_bits(failure_tree, rec->start,
+ rec->start + rec->len - 1,
+ EXTENT_LOCKED | EXTENT_DIRTY);
+ if (ret)
+ err = ret;
+
+ ret = clear_extent_bits(io_tree, rec->start,
+ rec->start + rec->len - 1,
+ EXTENT_DAMAGED);
+ if (ret && !err)
+ err = ret;
+
+ kfree(rec);
+ return err;
+}
+
+/*
+ * this bypasses the standard btrfs submit functions deliberately, as
+ * the standard behavior is to write all copies in a raid setup. here we only
+ * want to write the one bad copy. so we do the mapping for ourselves and issue
+ * submit_bio directly.
+ * to avoid any synchronization issues, wait for the data after writing, which
+ * actually prevents the read that triggered the error from finishing.
+ * currently, there can be no more than two copies of every data bit. thus,
+ * exactly one rewrite is required.
+ */
+int repair_io_failure(struct btrfs_fs_info *fs_info, u64 ino, u64 start,
+ u64 length, u64 logical, struct page *page,
+ unsigned int pg_offset, int mirror_num)
+{
+ struct bio *bio;
+ struct btrfs_device *dev;
+ u64 map_length = 0;
+ u64 sector;
+ struct btrfs_bio *bbio = NULL;
+ int ret;
+
+ ASSERT(!(fs_info->sb->s_flags & SB_RDONLY));
+ BUG_ON(!mirror_num);
+
+ bio = btrfs_io_bio_alloc(1);
+ bio->bi_iter.bi_size = 0;
+ map_length = length;
+
+ /*
+ * Avoid races with device replace and make sure our bbio has devices
+ * associated to its stripes that don't go away while we are doing the
+ * read repair operation.
+ */
+ btrfs_bio_counter_inc_blocked(fs_info);
+ if (btrfs_is_parity_mirror(fs_info, logical, length)) {
+ /*
+ * Note that we don't use BTRFS_MAP_WRITE because it's supposed
+ * to update all raid stripes, but here we just want to correct
+ * bad stripe, thus BTRFS_MAP_READ is abused to only get the bad
+ * stripe's dev and sector.
+ */
+ ret = btrfs_map_block(fs_info, BTRFS_MAP_READ, logical,
+ &map_length, &bbio, 0);
+ if (ret) {
+ btrfs_bio_counter_dec(fs_info);
+ bio_put(bio);
+ return -EIO;
+ }
+ ASSERT(bbio->mirror_num == 1);
+ } else {
+ ret = btrfs_map_block(fs_info, BTRFS_MAP_WRITE, logical,
+ &map_length, &bbio, mirror_num);
+ if (ret) {
+ btrfs_bio_counter_dec(fs_info);
+ bio_put(bio);
+ return -EIO;
+ }
+ BUG_ON(mirror_num != bbio->mirror_num);
+ }
+
+ sector = bbio->stripes[bbio->mirror_num - 1].physical >> 9;
+ bio->bi_iter.bi_sector = sector;
+ dev = bbio->stripes[bbio->mirror_num - 1].dev;
+ btrfs_put_bbio(bbio);
+ if (!dev || !dev->bdev ||
+ !test_bit(BTRFS_DEV_STATE_WRITEABLE, &dev->dev_state)) {
+ btrfs_bio_counter_dec(fs_info);
+ bio_put(bio);
+ return -EIO;
+ }
+ bio_set_dev(bio, dev->bdev);
+ bio->bi_opf = REQ_OP_WRITE | REQ_SYNC;
+ bio_add_page(bio, page, length, pg_offset);
+
+ if (btrfsic_submit_bio_wait(bio)) {
+ /* try to remap that extent elsewhere? */
+ btrfs_bio_counter_dec(fs_info);
+ bio_put(bio);
+ btrfs_dev_stat_inc_and_print(dev, BTRFS_DEV_STAT_WRITE_ERRS);
+ return -EIO;
+ }
+
+ btrfs_info_rl_in_rcu(fs_info,
+ "read error corrected: ino %llu off %llu (dev %s sector %llu)",
+ ino, start,
+ rcu_str_deref(dev->name), sector);
+ btrfs_bio_counter_dec(fs_info);
+ bio_put(bio);
+ return 0;
+}
+
+int repair_eb_io_failure(struct btrfs_fs_info *fs_info,
+ struct extent_buffer *eb, int mirror_num)
+{
+ u64 start = eb->start;
+ int i, num_pages = num_extent_pages(eb);
+ int ret = 0;
+
+ if (sb_rdonly(fs_info->sb))
+ return -EROFS;
+
+ for (i = 0; i < num_pages; i++) {
+ struct page *p = eb->pages[i];
+
+ ret = repair_io_failure(fs_info, 0, start, PAGE_SIZE, start, p,
+ start - page_offset(p), mirror_num);
+ if (ret)
+ break;
+ start += PAGE_SIZE;
+ }
+
+ return ret;
+}
+
+/*
+ * each time an IO finishes, we do a fast check in the IO failure tree
+ * to see if we need to process or clean up an io_failure_record
+ */
+int clean_io_failure(struct btrfs_fs_info *fs_info,
+ struct extent_io_tree *failure_tree,
+ struct extent_io_tree *io_tree, u64 start,
+ struct page *page, u64 ino, unsigned int pg_offset)
+{
+ u64 private;
+ struct io_failure_record *failrec;
+ struct extent_state *state;
+ int num_copies;
+ int ret;
+
+ private = 0;
+ ret = count_range_bits(failure_tree, &private, (u64)-1, 1,
+ EXTENT_DIRTY, 0);
+ if (!ret)
+ return 0;
+
+ ret = get_state_failrec(failure_tree, start, &failrec);
+ if (ret)
+ return 0;
+
+ BUG_ON(!failrec->this_mirror);
+
+ if (failrec->in_validation) {
+ /* there was no real error, just free the record */
+ btrfs_debug(fs_info,
+ "clean_io_failure: freeing dummy error at %llu",
+ failrec->start);
+ goto out;
+ }
+ if (sb_rdonly(fs_info->sb))
+ goto out;
+
+ spin_lock(&io_tree->lock);
+ state = find_first_extent_bit_state(io_tree,
+ failrec->start,
+ EXTENT_LOCKED);
+ spin_unlock(&io_tree->lock);
+
+ if (state && state->start <= failrec->start &&
+ state->end >= failrec->start + failrec->len - 1) {
+ num_copies = btrfs_num_copies(fs_info, failrec->logical,
+ failrec->len);
+ if (num_copies > 1) {
+ repair_io_failure(fs_info, ino, start, failrec->len,
+ failrec->logical, page, pg_offset,
+ failrec->failed_mirror);
+ }
+ }
+
+out:
+ free_io_failure(failure_tree, io_tree, failrec);
+
+ return 0;
+}
+
+/*
+ * Can be called when
+ * - hold extent lock
+ * - under ordered extent
+ * - the inode is freeing
+ */
+void btrfs_free_io_failure_record(struct btrfs_inode *inode, u64 start, u64 end)
+{
+ struct extent_io_tree *failure_tree = &inode->io_failure_tree;
+ struct io_failure_record *failrec;
+ struct extent_state *state, *next;
+
+ if (RB_EMPTY_ROOT(&failure_tree->state))
+ return;
+
+ spin_lock(&failure_tree->lock);
+ state = find_first_extent_bit_state(failure_tree, start, EXTENT_DIRTY);
+ while (state) {
+ if (state->start > end)
+ break;
+
+ ASSERT(state->end <= end);
+
+ next = next_state(state);
+
+ failrec = state->failrec;
+ free_extent_state(state);
+ kfree(failrec);
+
+ state = next;
+ }
+ spin_unlock(&failure_tree->lock);
+}
+
+int btrfs_get_io_failure_record(struct inode *inode, u64 start, u64 end,
+ struct io_failure_record **failrec_ret)
+{
+ struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
+ struct io_failure_record *failrec;
+ struct extent_map *em;
+ struct extent_io_tree *failure_tree = &BTRFS_I(inode)->io_failure_tree;
+ struct extent_io_tree *tree = &BTRFS_I(inode)->io_tree;
+ struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
+ int ret;
+ u64 logical;
+
+ ret = get_state_failrec(failure_tree, start, &failrec);
+ if (ret) {
+ failrec = kzalloc(sizeof(*failrec), GFP_NOFS);
+ if (!failrec)
+ return -ENOMEM;
+
+ failrec->start = start;
+ failrec->len = end - start + 1;
+ failrec->this_mirror = 0;
+ failrec->bio_flags = 0;
+ failrec->in_validation = 0;
+
+ read_lock(&em_tree->lock);
+ em = lookup_extent_mapping(em_tree, start, failrec->len);
+ if (!em) {
+ read_unlock(&em_tree->lock);
+ kfree(failrec);
+ return -EIO;
+ }
+
+ if (em->start > start || em->start + em->len <= start) {
+ free_extent_map(em);
+ em = NULL;
+ }
+ read_unlock(&em_tree->lock);
+ if (!em) {
+ kfree(failrec);
+ return -EIO;
+ }
+
+ logical = start - em->start;
+ logical = em->block_start + logical;
+ if (test_bit(EXTENT_FLAG_COMPRESSED, &em->flags)) {
+ logical = em->block_start;
+ failrec->bio_flags = EXTENT_BIO_COMPRESSED;
+ extent_set_compress_type(&failrec->bio_flags,
+ em->compress_type);
+ }
+
+ btrfs_debug(fs_info,
+ "Get IO Failure Record: (new) logical=%llu, start=%llu, len=%llu",
+ logical, start, failrec->len);
+
+ failrec->logical = logical;
+ free_extent_map(em);
+
+ /* set the bits in the private failure tree */
+ ret = set_extent_bits(failure_tree, start, end,
+ EXTENT_LOCKED | EXTENT_DIRTY);
+ if (ret >= 0)
+ ret = set_state_failrec(failure_tree, start, failrec);
+ /* set the bits in the inode's tree */
+ if (ret >= 0)
+ ret = set_extent_bits(tree, start, end, EXTENT_DAMAGED);
+ if (ret < 0) {
+ kfree(failrec);
+ return ret;
+ }
+ } else {
+ btrfs_debug(fs_info,
+ "Get IO Failure Record: (found) logical=%llu, start=%llu, len=%llu, validation=%d",
+ failrec->logical, failrec->start, failrec->len,
+ failrec->in_validation);
+ /*
+ * when data can be on disk more than twice, add to failrec here
+ * (e.g. with a list for failed_mirror) to make
+ * clean_io_failure() clean all those errors at once.
+ */
+ }
+
+ *failrec_ret = failrec;
+
+ return 0;
+}
+
+bool btrfs_check_repairable(struct inode *inode, unsigned failed_bio_pages,
+ struct io_failure_record *failrec, int failed_mirror)
+{
+ struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
+ int num_copies;
+
+ num_copies = btrfs_num_copies(fs_info, failrec->logical, failrec->len);
+ if (num_copies == 1) {
+ /*
+ * we only have a single copy of the data, so don't bother with
+ * all the retry and error correction code that follows. no
+ * matter what the error is, it is very likely to persist.
+ */
+ btrfs_debug(fs_info,
+ "Check Repairable: cannot repair, num_copies=%d, next_mirror %d, failed_mirror %d",
+ num_copies, failrec->this_mirror, failed_mirror);
+ return false;
+ }
+
+ /*
+ * there are two premises:
+ * a) deliver good data to the caller
+ * b) correct the bad sectors on disk
+ */
+ if (failed_bio_pages > 1) {
+ /*
+ * to fulfill b), we need to know the exact failing sectors, as
+ * we don't want to rewrite any more than the failed ones. thus,
+ * we need separate read requests for the failed bio
+ *
+ * if the following BUG_ON triggers, our validation request got
+ * merged. we need separate requests for our algorithm to work.
+ */
+ BUG_ON(failrec->in_validation);
+ failrec->in_validation = 1;
+ failrec->this_mirror = failed_mirror;
+ } else {
+ /*
+ * we're ready to fulfill a) and b) alongside. get a good copy
+ * of the failed sector and if we succeed, we have setup
+ * everything for repair_io_failure to do the rest for us.
+ */
+ if (failrec->in_validation) {
+ BUG_ON(failrec->this_mirror != failed_mirror);
+ failrec->in_validation = 0;
+ failrec->this_mirror = 0;
+ }
+ failrec->failed_mirror = failed_mirror;
+ failrec->this_mirror++;
+ if (failrec->this_mirror == failed_mirror)
+ failrec->this_mirror++;
+ }
+
+ if (failrec->this_mirror > num_copies) {
+ btrfs_debug(fs_info,
+ "Check Repairable: (fail) num_copies=%d, next_mirror %d, failed_mirror %d",
+ num_copies, failrec->this_mirror, failed_mirror);
+ return false;
+ }
+
+ return true;
+}
+
+
+struct bio *btrfs_create_repair_bio(struct inode *inode, struct bio *failed_bio,
+ struct io_failure_record *failrec,
+ struct page *page, int pg_offset, int icsum,
+ bio_end_io_t *endio_func, void *data)
+{
+ struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
+ struct bio *bio;
+ struct btrfs_io_bio *btrfs_failed_bio;
+ struct btrfs_io_bio *btrfs_bio;
+
+ bio = btrfs_io_bio_alloc(1);
+ bio->bi_end_io = endio_func;
+ bio->bi_iter.bi_sector = failrec->logical >> 9;
+ bio_set_dev(bio, fs_info->fs_devices->latest_bdev);
+ bio->bi_iter.bi_size = 0;
+ bio->bi_private = data;
+
+ btrfs_failed_bio = btrfs_io_bio(failed_bio);
+ if (btrfs_failed_bio->csum) {
+ u16 csum_size = btrfs_super_csum_size(fs_info->super_copy);
+
+ btrfs_bio = btrfs_io_bio(bio);
+ btrfs_bio->csum = btrfs_bio->csum_inline;
+ icsum *= csum_size;
+ memcpy(btrfs_bio->csum, btrfs_failed_bio->csum + icsum,
+ csum_size);
+ }
+
+ bio_add_page(bio, page, failrec->len, pg_offset);
+
+ return bio;
+}
+
+/*
+ * this is a generic handler for readpage errors (default
+ * readpage_io_failed_hook). if other copies exist, read those and write back
+ * good data to the failed position. does not investigate in remapping the
+ * failed extent elsewhere, hoping the device will be smart enough to do this as
+ * needed
+ */
+
+static int bio_readpage_error(struct bio *failed_bio, u64 phy_offset,
+ struct page *page, u64 start, u64 end,
+ int failed_mirror)
+{
+ struct io_failure_record *failrec;
+ struct inode *inode = page->mapping->host;
+ struct extent_io_tree *tree = &BTRFS_I(inode)->io_tree;
+ struct extent_io_tree *failure_tree = &BTRFS_I(inode)->io_failure_tree;
+ struct bio *bio;
+ int read_mode = 0;
+ blk_status_t status;
+ int ret;
+ unsigned failed_bio_pages = bio_pages_all(failed_bio);
+
+ BUG_ON(bio_op(failed_bio) == REQ_OP_WRITE);
+
+ ret = btrfs_get_io_failure_record(inode, start, end, &failrec);
+ if (ret)
+ return ret;
+
+ if (!btrfs_check_repairable(inode, failed_bio_pages, failrec,
+ failed_mirror)) {
+ free_io_failure(failure_tree, tree, failrec);
+ return -EIO;
+ }
+
+ if (failed_bio_pages > 1)
+ read_mode |= REQ_FAILFAST_DEV;
+
+ phy_offset >>= inode->i_sb->s_blocksize_bits;
+ bio = btrfs_create_repair_bio(inode, failed_bio, failrec, page,
+ start - page_offset(page),
+ (int)phy_offset, failed_bio->bi_end_io,
+ NULL);
+ bio->bi_opf = REQ_OP_READ | read_mode;
+
+ btrfs_debug(btrfs_sb(inode->i_sb),
+ "Repair Read Error: submitting new read[%#x] to this_mirror=%d, in_validation=%d",
+ read_mode, failrec->this_mirror, failrec->in_validation);
+
+ status = tree->ops->submit_bio_hook(tree->private_data, bio, failrec->this_mirror,
+ failrec->bio_flags, 0);
+ if (status) {
+ free_io_failure(failure_tree, tree, failrec);
+ bio_put(bio);
+ ret = blk_status_to_errno(status);
+ }
+
+ return ret;
+}
+
+/* lots and lots of room for performance fixes in the end_bio funcs */
+
+void end_extent_writepage(struct page *page, int err, u64 start, u64 end)
+{
+ int uptodate = (err == 0);
+ struct extent_io_tree *tree;
+ int ret = 0;
+
+ tree = &BTRFS_I(page->mapping->host)->io_tree;
+
+ if (tree->ops && tree->ops->writepage_end_io_hook)
+ tree->ops->writepage_end_io_hook(page, start, end, NULL,
+ uptodate);
+
+ if (!uptodate) {
+ ClearPageUptodate(page);
+ SetPageError(page);
+ ret = err < 0 ? err : -EIO;
+ mapping_set_error(page->mapping, ret);
+ }
+}
+
+/*
+ * after a writepage IO is done, we need to:
+ * clear the uptodate bits on error
+ * clear the writeback bits in the extent tree for this IO
+ * end_page_writeback if the page has no more pending IO
+ *
+ * Scheduling is not allowed, so the extent state tree is expected
+ * to have one and only one object corresponding to this IO.
+ */
+static void end_bio_extent_writepage(struct bio *bio)
+{
+ int error = blk_status_to_errno(bio->bi_status);
+ struct bio_vec *bvec;
+ u64 start;
+ u64 end;
+ int i;
+
+ ASSERT(!bio_flagged(bio, BIO_CLONED));
+ bio_for_each_segment_all(bvec, bio, i) {
+ struct page *page = bvec->bv_page;
+ struct inode *inode = page->mapping->host;
+ struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
+
+ /* We always issue full-page reads, but if some block
+ * in a page fails to read, blk_update_request() will
+ * advance bv_offset and adjust bv_len to compensate.
+ * Print a warning for nonzero offsets, and an error
+ * if they don't add up to a full page. */
+ if (bvec->bv_offset || bvec->bv_len != PAGE_SIZE) {
+ if (bvec->bv_offset + bvec->bv_len != PAGE_SIZE)
+ btrfs_err(fs_info,
+ "partial page write in btrfs with offset %u and length %u",
+ bvec->bv_offset, bvec->bv_len);
+ else
+ btrfs_info(fs_info,
+ "incomplete page write in btrfs with offset %u and length %u",
+ bvec->bv_offset, bvec->bv_len);
+ }
+
+ start = page_offset(page);
+ end = start + bvec->bv_offset + bvec->bv_len - 1;
+
+ end_extent_writepage(page, error, start, end);
+ end_page_writeback(page);
+ }
+
+ bio_put(bio);
+}
+
+static void
+endio_readpage_release_extent(struct extent_io_tree *tree, u64 start, u64 len,
+ int uptodate)
+{
+ struct extent_state *cached = NULL;
+ u64 end = start + len - 1;
+
+ if (uptodate && tree->track_uptodate)
+ set_extent_uptodate(tree, start, end, &cached, GFP_ATOMIC);
+ unlock_extent_cached_atomic(tree, start, end, &cached);
+}
+
+/*
+ * after a readpage IO is done, we need to:
+ * clear the uptodate bits on error
+ * set the uptodate bits if things worked
+ * set the page up to date if all extents in the tree are uptodate
+ * clear the lock bit in the extent tree
+ * unlock the page if there are no other extents locked for it
+ *
+ * Scheduling is not allowed, so the extent state tree is expected
+ * to have one and only one object corresponding to this IO.
+ */
+static void end_bio_extent_readpage(struct bio *bio)
+{
+ struct bio_vec *bvec;
+ int uptodate = !bio->bi_status;
+ struct btrfs_io_bio *io_bio = btrfs_io_bio(bio);
+ struct extent_io_tree *tree, *failure_tree;
+ u64 offset = 0;
+ u64 start;
+ u64 end;
+ u64 len;
+ u64 extent_start = 0;
+ u64 extent_len = 0;
+ int mirror;
+ int ret;
+ int i;
+
+ ASSERT(!bio_flagged(bio, BIO_CLONED));
+ bio_for_each_segment_all(bvec, bio, i) {
+ struct page *page = bvec->bv_page;
+ struct inode *inode = page->mapping->host;
+ struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
+
+ btrfs_debug(fs_info,
+ "end_bio_extent_readpage: bi_sector=%llu, err=%d, mirror=%u",
+ (u64)bio->bi_iter.bi_sector, bio->bi_status,
+ io_bio->mirror_num);
+ tree = &BTRFS_I(inode)->io_tree;
+ failure_tree = &BTRFS_I(inode)->io_failure_tree;
+
+ /* We always issue full-page reads, but if some block
+ * in a page fails to read, blk_update_request() will
+ * advance bv_offset and adjust bv_len to compensate.
+ * Print a warning for nonzero offsets, and an error
+ * if they don't add up to a full page. */
+ if (bvec->bv_offset || bvec->bv_len != PAGE_SIZE) {
+ if (bvec->bv_offset + bvec->bv_len != PAGE_SIZE)
+ btrfs_err(fs_info,
+ "partial page read in btrfs with offset %u and length %u",
+ bvec->bv_offset, bvec->bv_len);
+ else
+ btrfs_info(fs_info,
+ "incomplete page read in btrfs with offset %u and length %u",
+ bvec->bv_offset, bvec->bv_len);
+ }
+
+ start = page_offset(page);
+ end = start + bvec->bv_offset + bvec->bv_len - 1;
+ len = bvec->bv_len;
+
+ mirror = io_bio->mirror_num;
+ if (likely(uptodate && tree->ops)) {
+ ret = tree->ops->readpage_end_io_hook(io_bio, offset,
+ page, start, end,
+ mirror);
+ if (ret)
+ uptodate = 0;
+ else
+ clean_io_failure(BTRFS_I(inode)->root->fs_info,
+ failure_tree, tree, start,
+ page,
+ btrfs_ino(BTRFS_I(inode)), 0);
+ }
+
+ if (likely(uptodate))
+ goto readpage_ok;
+
+ if (tree->ops) {
+ ret = tree->ops->readpage_io_failed_hook(page, mirror);
+ if (ret == -EAGAIN) {
+ /*
+ * Data inode's readpage_io_failed_hook() always
+ * returns -EAGAIN.
+ *
+ * The generic bio_readpage_error handles errors
+ * the following way: If possible, new read
+ * requests are created and submitted and will
+ * end up in end_bio_extent_readpage as well (if
+ * we're lucky, not in the !uptodate case). In
+ * that case it returns 0 and we just go on with
+ * the next page in our bio. If it can't handle
+ * the error it will return -EIO and we remain
+ * responsible for that page.
+ */
+ ret = bio_readpage_error(bio, offset, page,
+ start, end, mirror);
+ if (ret == 0) {
+ uptodate = !bio->bi_status;
+ offset += len;
+ continue;
+ }
+ }
+
+ /*
+ * metadata's readpage_io_failed_hook() always returns
+ * -EIO and fixes nothing. -EIO is also returned if
+ * data inode error could not be fixed.
+ */
+ ASSERT(ret == -EIO);
+ }
+readpage_ok:
+ if (likely(uptodate)) {
+ loff_t i_size = i_size_read(inode);
+ pgoff_t end_index = i_size >> PAGE_SHIFT;
+ unsigned off;
+
+ /* Zero out the end if this page straddles i_size */
+ off = i_size & (PAGE_SIZE-1);
+ if (page->index == end_index && off)
+ zero_user_segment(page, off, PAGE_SIZE);
+ SetPageUptodate(page);
+ } else {
+ ClearPageUptodate(page);
+ SetPageError(page);
+ }
+ unlock_page(page);
+ offset += len;
+
+ if (unlikely(!uptodate)) {
+ if (extent_len) {
+ endio_readpage_release_extent(tree,
+ extent_start,
+ extent_len, 1);
+ extent_start = 0;
+ extent_len = 0;
+ }
+ endio_readpage_release_extent(tree, start,
+ end - start + 1, 0);
+ } else if (!extent_len) {
+ extent_start = start;
+ extent_len = end + 1 - start;
+ } else if (extent_start + extent_len == start) {
+ extent_len += end + 1 - start;
+ } else {
+ endio_readpage_release_extent(tree, extent_start,
+ extent_len, uptodate);
+ extent_start = start;
+ extent_len = end + 1 - start;
+ }
+ }
+
+ if (extent_len)
+ endio_readpage_release_extent(tree, extent_start, extent_len,
+ uptodate);
+ if (io_bio->end_io)
+ io_bio->end_io(io_bio, blk_status_to_errno(bio->bi_status));
+ bio_put(bio);
+}
+
+/*
+ * Initialize the members up to but not including 'bio'. Use after allocating a
+ * new bio by bio_alloc_bioset as it does not initialize the bytes outside of
+ * 'bio' because use of __GFP_ZERO is not supported.
+ */
+static inline void btrfs_io_bio_init(struct btrfs_io_bio *btrfs_bio)
+{
+ memset(btrfs_bio, 0, offsetof(struct btrfs_io_bio, bio));
+}
+
+/*
+ * The following helpers allocate a bio. As it's backed by a bioset, it'll
+ * never fail. We're returning a bio right now but you can call btrfs_io_bio
+ * for the appropriate container_of magic
+ */
+struct bio *btrfs_bio_alloc(struct block_device *bdev, u64 first_byte)
+{
+ struct bio *bio;
+
+ bio = bio_alloc_bioset(GFP_NOFS, BIO_MAX_PAGES, &btrfs_bioset);
+ bio_set_dev(bio, bdev);
+ bio->bi_iter.bi_sector = first_byte >> 9;
+ btrfs_io_bio_init(btrfs_io_bio(bio));
+ return bio;
+}
+
+struct bio *btrfs_bio_clone(struct bio *bio)
+{
+ struct btrfs_io_bio *btrfs_bio;
+ struct bio *new;
+
+ /* Bio allocation backed by a bioset does not fail */
+ new = bio_clone_fast(bio, GFP_NOFS, &btrfs_bioset);
+ btrfs_bio = btrfs_io_bio(new);
+ btrfs_io_bio_init(btrfs_bio);
+ btrfs_bio->iter = bio->bi_iter;
+ return new;
+}
+
+struct bio *btrfs_io_bio_alloc(unsigned int nr_iovecs)
+{
+ struct bio *bio;
+
+ /* Bio allocation backed by a bioset does not fail */
+ bio = bio_alloc_bioset(GFP_NOFS, nr_iovecs, &btrfs_bioset);
+ btrfs_io_bio_init(btrfs_io_bio(bio));
+ return bio;
+}
+
+struct bio *btrfs_bio_clone_partial(struct bio *orig, int offset, int size)
+{
+ struct bio *bio;
+ struct btrfs_io_bio *btrfs_bio;
+
+ /* this will never fail when it's backed by a bioset */
+ bio = bio_clone_fast(orig, GFP_NOFS, &btrfs_bioset);
+ ASSERT(bio);
+
+ btrfs_bio = btrfs_io_bio(bio);
+ btrfs_io_bio_init(btrfs_bio);
+
+ bio_trim(bio, offset >> 9, size >> 9);
+ btrfs_bio->iter = bio->bi_iter;
+ return bio;
+}
+
+static int __must_check submit_one_bio(struct bio *bio, int mirror_num,
+ unsigned long bio_flags)
+{
+ blk_status_t ret = 0;
+ struct bio_vec *bvec = bio_last_bvec_all(bio);
+ struct page *page = bvec->bv_page;
+ struct extent_io_tree *tree = bio->bi_private;
+ u64 start;
+
+ start = page_offset(page) + bvec->bv_offset;
+
+ bio->bi_private = NULL;
+
+ if (tree->ops)
+ ret = tree->ops->submit_bio_hook(tree->private_data, bio,
+ mirror_num, bio_flags, start);
+ else
+ btrfsic_submit_bio(bio);
+
+ return blk_status_to_errno(ret);
+}
+
+/*
+ * @opf: bio REQ_OP_* and REQ_* flags as one value
+ * @tree: tree so we can call our merge_bio hook
+ * @wbc: optional writeback control for io accounting
+ * @page: page to add to the bio
+ * @pg_offset: offset of the new bio or to check whether we are adding
+ * a contiguous page to the previous one
+ * @size: portion of page that we want to write
+ * @offset: starting offset in the page
+ * @bdev: attach newly created bios to this bdev
+ * @bio_ret: must be valid pointer, newly allocated bio will be stored there
+ * @end_io_func: end_io callback for new bio
+ * @mirror_num: desired mirror to read/write
+ * @prev_bio_flags: flags of previous bio to see if we can merge the current one
+ * @bio_flags: flags of the current bio to see if we can merge them
+ */
+static int submit_extent_page(unsigned int opf, struct extent_io_tree *tree,
+ struct writeback_control *wbc,
+ struct page *page, u64 offset,
+ size_t size, unsigned long pg_offset,
+ struct block_device *bdev,
+ struct bio **bio_ret,
+ bio_end_io_t end_io_func,
+ int mirror_num,
+ unsigned long prev_bio_flags,
+ unsigned long bio_flags,
+ bool force_bio_submit)
+{
+ int ret = 0;
+ struct bio *bio;
+ size_t page_size = min_t(size_t, size, PAGE_SIZE);
+ sector_t sector = offset >> 9;
+
+ ASSERT(bio_ret);
+
+ if (*bio_ret) {
+ bool contig;
+ bool can_merge = true;
+
+ bio = *bio_ret;
+ if (prev_bio_flags & EXTENT_BIO_COMPRESSED)
+ contig = bio->bi_iter.bi_sector == sector;
+ else
+ contig = bio_end_sector(bio) == sector;
+
+ if (tree->ops && btrfs_merge_bio_hook(page, offset, page_size,
+ bio, bio_flags))
+ can_merge = false;
+
+ if (prev_bio_flags != bio_flags || !contig || !can_merge ||
+ force_bio_submit ||
+ bio_add_page(bio, page, page_size, pg_offset) < page_size) {
+ ret = submit_one_bio(bio, mirror_num, prev_bio_flags);
+ if (ret < 0) {
+ *bio_ret = NULL;
+ return ret;
+ }
+ bio = NULL;
+ } else {
+ if (wbc)
+ wbc_account_io(wbc, page, page_size);
+ return 0;
+ }
+ }
+
+ bio = btrfs_bio_alloc(bdev, offset);
+ bio_add_page(bio, page, page_size, pg_offset);
+ bio->bi_end_io = end_io_func;
+ bio->bi_private = tree;
+ bio->bi_write_hint = page->mapping->host->i_write_hint;
+ bio->bi_opf = opf;
+ if (wbc) {
+ wbc_init_bio(wbc, bio);
+ wbc_account_io(wbc, page, page_size);
+ }
+
+ *bio_ret = bio;
+
+ return ret;
+}
+
+static void attach_extent_buffer_page(struct extent_buffer *eb,
+ struct page *page)
+{
+ if (!PagePrivate(page)) {
+ SetPagePrivate(page);
+ get_page(page);
+ set_page_private(page, (unsigned long)eb);
+ } else {
+ WARN_ON(page->private != (unsigned long)eb);
+ }
+}
+
+void set_page_extent_mapped(struct page *page)
+{
+ if (!PagePrivate(page)) {
+ SetPagePrivate(page);
+ get_page(page);
+ set_page_private(page, EXTENT_PAGE_PRIVATE);
+ }
+}
+
+static struct extent_map *
+__get_extent_map(struct inode *inode, struct page *page, size_t pg_offset,
+ u64 start, u64 len, get_extent_t *get_extent,
+ struct extent_map **em_cached)
+{
+ struct extent_map *em;
+
+ if (em_cached && *em_cached) {
+ em = *em_cached;
+ if (extent_map_in_tree(em) && start >= em->start &&
+ start < extent_map_end(em)) {
+ refcount_inc(&em->refs);
+ return em;
+ }
+
+ free_extent_map(em);
+ *em_cached = NULL;
+ }
+
+ em = get_extent(BTRFS_I(inode), page, pg_offset, start, len, 0);
+ if (em_cached && !IS_ERR_OR_NULL(em)) {
+ BUG_ON(*em_cached);
+ refcount_inc(&em->refs);
+ *em_cached = em;
+ }
+ return em;
+}
+/*
+ * basic readpage implementation. Locked extent state structs are inserted
+ * into the tree that are removed when the IO is done (by the end_io
+ * handlers)
+ * XXX JDM: This needs looking at to ensure proper page locking
+ * return 0 on success, otherwise return error
+ */
+static int __do_readpage(struct extent_io_tree *tree,
+ struct page *page,
+ get_extent_t *get_extent,
+ struct extent_map **em_cached,
+ struct bio **bio, int mirror_num,
+ unsigned long *bio_flags, unsigned int read_flags,
+ u64 *prev_em_start)
+{
+ struct inode *inode = page->mapping->host;
+ u64 start = page_offset(page);
+ const u64 end = start + PAGE_SIZE - 1;
+ u64 cur = start;
+ u64 extent_offset;
+ u64 last_byte = i_size_read(inode);
+ u64 block_start;
+ u64 cur_end;
+ struct extent_map *em;
+ struct block_device *bdev;
+ int ret = 0;
+ int nr = 0;
+ size_t pg_offset = 0;
+ size_t iosize;
+ size_t disk_io_size;
+ size_t blocksize = inode->i_sb->s_blocksize;
+ unsigned long this_bio_flag = 0;
+
+ set_page_extent_mapped(page);
+
+ if (!PageUptodate(page)) {
+ if (cleancache_get_page(page) == 0) {
+ BUG_ON(blocksize != PAGE_SIZE);
+ unlock_extent(tree, start, end);
+ goto out;
+ }
+ }
+
+ if (page->index == last_byte >> PAGE_SHIFT) {
+ char *userpage;
+ size_t zero_offset = last_byte & (PAGE_SIZE - 1);
+
+ if (zero_offset) {
+ iosize = PAGE_SIZE - zero_offset;
+ userpage = kmap_atomic(page);
+ memset(userpage + zero_offset, 0, iosize);
+ flush_dcache_page(page);
+ kunmap_atomic(userpage);
+ }
+ }
+ while (cur <= end) {
+ bool force_bio_submit = false;
+ u64 offset;
+
+ if (cur >= last_byte) {
+ char *userpage;
+ struct extent_state *cached = NULL;
+
+ iosize = PAGE_SIZE - pg_offset;
+ userpage = kmap_atomic(page);
+ memset(userpage + pg_offset, 0, iosize);
+ flush_dcache_page(page);
+ kunmap_atomic(userpage);
+ set_extent_uptodate(tree, cur, cur + iosize - 1,
+ &cached, GFP_NOFS);
+ unlock_extent_cached(tree, cur,
+ cur + iosize - 1, &cached);
+ break;
+ }
+ em = __get_extent_map(inode, page, pg_offset, cur,
+ end - cur + 1, get_extent, em_cached);
+ if (IS_ERR_OR_NULL(em)) {
+ SetPageError(page);
+ unlock_extent(tree, cur, end);
+ break;
+ }
+ extent_offset = cur - em->start;
+ BUG_ON(extent_map_end(em) <= cur);
+ BUG_ON(end < cur);
+
+ if (test_bit(EXTENT_FLAG_COMPRESSED, &em->flags)) {
+ this_bio_flag |= EXTENT_BIO_COMPRESSED;
+ extent_set_compress_type(&this_bio_flag,
+ em->compress_type);
+ }
+
+ iosize = min(extent_map_end(em) - cur, end - cur + 1);
+ cur_end = min(extent_map_end(em) - 1, end);
+ iosize = ALIGN(iosize, blocksize);
+ if (this_bio_flag & EXTENT_BIO_COMPRESSED) {
+ disk_io_size = em->block_len;
+ offset = em->block_start;
+ } else {
+ offset = em->block_start + extent_offset;
+ disk_io_size = iosize;
+ }
+ bdev = em->bdev;
+ block_start = em->block_start;
+ if (test_bit(EXTENT_FLAG_PREALLOC, &em->flags))
+ block_start = EXTENT_MAP_HOLE;
+
+ /*
+ * If we have a file range that points to a compressed extent
+ * and it's followed by a consecutive file range that points to
+ * to the same compressed extent (possibly with a different
+ * offset and/or length, so it either points to the whole extent
+ * or only part of it), we must make sure we do not submit a
+ * single bio to populate the pages for the 2 ranges because
+ * this makes the compressed extent read zero out the pages
+ * belonging to the 2nd range. Imagine the following scenario:
+ *
+ * File layout
+ * [0 - 8K] [8K - 24K]
+ * | |
+ * | |
+ * points to extent X, points to extent X,
+ * offset 4K, length of 8K offset 0, length 16K
+ *
+ * [extent X, compressed length = 4K uncompressed length = 16K]
+ *
+ * If the bio to read the compressed extent covers both ranges,
+ * it will decompress extent X into the pages belonging to the
+ * first range and then it will stop, zeroing out the remaining
+ * pages that belong to the other range that points to extent X.
+ * So here we make sure we submit 2 bios, one for the first
+ * range and another one for the third range. Both will target
+ * the same physical extent from disk, but we can't currently
+ * make the compressed bio endio callback populate the pages
+ * for both ranges because each compressed bio is tightly
+ * coupled with a single extent map, and each range can have
+ * an extent map with a different offset value relative to the
+ * uncompressed data of our extent and different lengths. This
+ * is a corner case so we prioritize correctness over
+ * non-optimal behavior (submitting 2 bios for the same extent).
+ */
+ if (test_bit(EXTENT_FLAG_COMPRESSED, &em->flags) &&
+ prev_em_start && *prev_em_start != (u64)-1 &&
+ *prev_em_start != em->orig_start)
+ force_bio_submit = true;
+
+ if (prev_em_start)
+ *prev_em_start = em->orig_start;
+
+ free_extent_map(em);
+ em = NULL;
+
+ /* we've found a hole, just zero and go on */
+ if (block_start == EXTENT_MAP_HOLE) {
+ char *userpage;
+ struct extent_state *cached = NULL;
+
+ userpage = kmap_atomic(page);
+ memset(userpage + pg_offset, 0, iosize);
+ flush_dcache_page(page);
+ kunmap_atomic(userpage);
+
+ set_extent_uptodate(tree, cur, cur + iosize - 1,
+ &cached, GFP_NOFS);
+ unlock_extent_cached(tree, cur,
+ cur + iosize - 1, &cached);
+ cur = cur + iosize;
+ pg_offset += iosize;
+ continue;
+ }
+ /* the get_extent function already copied into the page */
+ if (test_range_bit(tree, cur, cur_end,
+ EXTENT_UPTODATE, 1, NULL)) {
+ check_page_uptodate(tree, page);
+ unlock_extent(tree, cur, cur + iosize - 1);
+ cur = cur + iosize;
+ pg_offset += iosize;
+ continue;
+ }
+ /* we have an inline extent but it didn't get marked up
+ * to date. Error out
+ */
+ if (block_start == EXTENT_MAP_INLINE) {
+ SetPageError(page);
+ unlock_extent(tree, cur, cur + iosize - 1);
+ cur = cur + iosize;
+ pg_offset += iosize;
+ continue;
+ }
+
+ ret = submit_extent_page(REQ_OP_READ | read_flags, tree, NULL,
+ page, offset, disk_io_size,
+ pg_offset, bdev, bio,
+ end_bio_extent_readpage, mirror_num,
+ *bio_flags,
+ this_bio_flag,
+ force_bio_submit);
+ if (!ret) {
+ nr++;
+ *bio_flags = this_bio_flag;
+ } else {
+ SetPageError(page);
+ unlock_extent(tree, cur, cur + iosize - 1);
+ goto out;
+ }
+ cur = cur + iosize;
+ pg_offset += iosize;
+ }
+out:
+ if (!nr) {
+ if (!PageError(page))
+ SetPageUptodate(page);
+ unlock_page(page);
+ }
+ return ret;
+}
+
+static inline void __do_contiguous_readpages(struct extent_io_tree *tree,
+ struct page *pages[], int nr_pages,
+ u64 start, u64 end,
+ struct extent_map **em_cached,
+ struct bio **bio,
+ unsigned long *bio_flags,
+ u64 *prev_em_start)
+{
+ struct inode *inode;
+ struct btrfs_ordered_extent *ordered;
+ int index;
+
+ inode = pages[0]->mapping->host;
+ while (1) {
+ lock_extent(tree, start, end);
+ ordered = btrfs_lookup_ordered_range(BTRFS_I(inode), start,
+ end - start + 1);
+ if (!ordered)
+ break;
+ unlock_extent(tree, start, end);
+ btrfs_start_ordered_extent(inode, ordered, 1);
+ btrfs_put_ordered_extent(ordered);
+ }
+
+ for (index = 0; index < nr_pages; index++) {
+ __do_readpage(tree, pages[index], btrfs_get_extent, em_cached,
+ bio, 0, bio_flags, REQ_RAHEAD, prev_em_start);
+ put_page(pages[index]);
+ }
+}
+
+static void __extent_readpages(struct extent_io_tree *tree,
+ struct page *pages[],
+ int nr_pages,
+ struct extent_map **em_cached,
+ struct bio **bio, unsigned long *bio_flags,
+ u64 *prev_em_start)
+{
+ u64 start = 0;
+ u64 end = 0;
+ u64 page_start;
+ int index;
+ int first_index = 0;
+
+ for (index = 0; index < nr_pages; index++) {
+ page_start = page_offset(pages[index]);
+ if (!end) {
+ start = page_start;
+ end = start + PAGE_SIZE - 1;
+ first_index = index;
+ } else if (end + 1 == page_start) {
+ end += PAGE_SIZE;
+ } else {
+ __do_contiguous_readpages(tree, &pages[first_index],
+ index - first_index, start,
+ end, em_cached,
+ bio, bio_flags,
+ prev_em_start);
+ start = page_start;
+ end = start + PAGE_SIZE - 1;
+ first_index = index;
+ }
+ }
+
+ if (end)
+ __do_contiguous_readpages(tree, &pages[first_index],
+ index - first_index, start,
+ end, em_cached, bio,
+ bio_flags, prev_em_start);
+}
+
+static int __extent_read_full_page(struct extent_io_tree *tree,
+ struct page *page,
+ get_extent_t *get_extent,
+ struct bio **bio, int mirror_num,
+ unsigned long *bio_flags,
+ unsigned int read_flags)
+{
+ struct inode *inode = page->mapping->host;
+ struct btrfs_ordered_extent *ordered;
+ u64 start = page_offset(page);
+ u64 end = start + PAGE_SIZE - 1;
+ int ret;
+
+ while (1) {
+ lock_extent(tree, start, end);
+ ordered = btrfs_lookup_ordered_range(BTRFS_I(inode), start,
+ PAGE_SIZE);
+ if (!ordered)
+ break;
+ unlock_extent(tree, start, end);
+ btrfs_start_ordered_extent(inode, ordered, 1);
+ btrfs_put_ordered_extent(ordered);
+ }
+
+ ret = __do_readpage(tree, page, get_extent, NULL, bio, mirror_num,
+ bio_flags, read_flags, NULL);
+ return ret;
+}
+
+int extent_read_full_page(struct extent_io_tree *tree, struct page *page,
+ get_extent_t *get_extent, int mirror_num)
+{
+ struct bio *bio = NULL;
+ unsigned long bio_flags = 0;
+ int ret;
+
+ ret = __extent_read_full_page(tree, page, get_extent, &bio, mirror_num,
+ &bio_flags, 0);
+ if (bio)
+ ret = submit_one_bio(bio, mirror_num, bio_flags);
+ return ret;
+}
+
+static void update_nr_written(struct writeback_control *wbc,
+ unsigned long nr_written)
+{
+ wbc->nr_to_write -= nr_written;
+}
+
+/*
+ * helper for __extent_writepage, doing all of the delayed allocation setup.
+ *
+ * This returns 1 if our fill_delalloc function did all the work required
+ * to write the page (copy into inline extent). In this case the IO has
+ * been started and the page is already unlocked.
+ *
+ * This returns 0 if all went well (page still locked)
+ * This returns < 0 if there were errors (page still locked)
+ */
+static noinline_for_stack int writepage_delalloc(struct inode *inode,
+ struct page *page, struct writeback_control *wbc,
+ struct extent_page_data *epd,
+ u64 delalloc_start,
+ unsigned long *nr_written)
+{
+ struct extent_io_tree *tree = epd->tree;
+ u64 page_end = delalloc_start + PAGE_SIZE - 1;
+ u64 nr_delalloc;
+ u64 delalloc_to_write = 0;
+ u64 delalloc_end = 0;
+ int ret;
+ int page_started = 0;
+
+ if (epd->extent_locked || !tree->ops || !tree->ops->fill_delalloc)
+ return 0;
+
+ while (delalloc_end < page_end) {
+ nr_delalloc = find_lock_delalloc_range(inode, tree,
+ page,
+ &delalloc_start,
+ &delalloc_end,
+ BTRFS_MAX_EXTENT_SIZE);
+ if (nr_delalloc == 0) {
+ delalloc_start = delalloc_end + 1;
+ continue;
+ }
+ ret = tree->ops->fill_delalloc(inode, page,
+ delalloc_start,
+ delalloc_end,
+ &page_started,
+ nr_written, wbc);
+ /* File system has been set read-only */
+ if (ret) {
+ SetPageError(page);
+ /* fill_delalloc should be return < 0 for error
+ * but just in case, we use > 0 here meaning the
+ * IO is started, so we don't want to return > 0
+ * unless things are going well.
+ */
+ ret = ret < 0 ? ret : -EIO;
+ goto done;
+ }
+ /*
+ * delalloc_end is already one less than the total length, so
+ * we don't subtract one from PAGE_SIZE
+ */
+ delalloc_to_write += (delalloc_end - delalloc_start +
+ PAGE_SIZE) >> PAGE_SHIFT;
+ delalloc_start = delalloc_end + 1;
+ }
+ if (wbc->nr_to_write < delalloc_to_write) {
+ int thresh = 8192;
+
+ if (delalloc_to_write < thresh * 2)
+ thresh = delalloc_to_write;
+ wbc->nr_to_write = min_t(u64, delalloc_to_write,
+ thresh);
+ }
+
+ /* did the fill delalloc function already unlock and start
+ * the IO?
+ */
+ if (page_started) {
+ /*
+ * we've unlocked the page, so we can't update
+ * the mapping's writeback index, just update
+ * nr_to_write.
+ */
+ wbc->nr_to_write -= *nr_written;
+ return 1;
+ }
+
+ ret = 0;
+
+done:
+ return ret;
+}
+
+/*
+ * helper for __extent_writepage. This calls the writepage start hooks,
+ * and does the loop to map the page into extents and bios.
+ *
+ * We return 1 if the IO is started and the page is unlocked,
+ * 0 if all went well (page still locked)
+ * < 0 if there were errors (page still locked)
+ */
+static noinline_for_stack int __extent_writepage_io(struct inode *inode,
+ struct page *page,
+ struct writeback_control *wbc,
+ struct extent_page_data *epd,
+ loff_t i_size,
+ unsigned long nr_written,
+ unsigned int write_flags, int *nr_ret)
+{
+ struct extent_io_tree *tree = epd->tree;
+ u64 start = page_offset(page);
+ u64 page_end = start + PAGE_SIZE - 1;
+ u64 end;
+ u64 cur = start;
+ u64 extent_offset;
+ u64 block_start;
+ u64 iosize;
+ struct extent_map *em;
+ struct block_device *bdev;
+ size_t pg_offset = 0;
+ size_t blocksize;
+ int ret = 0;
+ int nr = 0;
+ bool compressed;
+
+ if (tree->ops && tree->ops->writepage_start_hook) {
+ ret = tree->ops->writepage_start_hook(page, start,
+ page_end);
+ if (ret) {
+ /* Fixup worker will requeue */
+ if (ret == -EBUSY)
+ wbc->pages_skipped++;
+ else
+ redirty_page_for_writepage(wbc, page);
+
+ update_nr_written(wbc, nr_written);
+ unlock_page(page);
+ return 1;
+ }
+ }
+
+ /*
+ * we don't want to touch the inode after unlocking the page,
+ * so we update the mapping writeback index now
+ */
+ update_nr_written(wbc, nr_written + 1);
+
+ end = page_end;
+ if (i_size <= start) {
+ if (tree->ops && tree->ops->writepage_end_io_hook)
+ tree->ops->writepage_end_io_hook(page, start,
+ page_end, NULL, 1);
+ goto done;
+ }
+
+ blocksize = inode->i_sb->s_blocksize;
+
+ while (cur <= end) {
+ u64 em_end;
+ u64 offset;
+
+ if (cur >= i_size) {
+ if (tree->ops && tree->ops->writepage_end_io_hook)
+ tree->ops->writepage_end_io_hook(page, cur,
+ page_end, NULL, 1);
+ break;
+ }
+ em = btrfs_get_extent(BTRFS_I(inode), page, pg_offset, cur,
+ end - cur + 1, 1);
+ if (IS_ERR_OR_NULL(em)) {
+ SetPageError(page);
+ ret = PTR_ERR_OR_ZERO(em);
+ break;
+ }
+
+ extent_offset = cur - em->start;
+ em_end = extent_map_end(em);
+ BUG_ON(em_end <= cur);
+ BUG_ON(end < cur);
+ iosize = min(em_end - cur, end - cur + 1);
+ iosize = ALIGN(iosize, blocksize);
+ offset = em->block_start + extent_offset;
+ bdev = em->bdev;
+ block_start = em->block_start;
+ compressed = test_bit(EXTENT_FLAG_COMPRESSED, &em->flags);
+ free_extent_map(em);
+ em = NULL;
+
+ /*
+ * compressed and inline extents are written through other
+ * paths in the FS
+ */
+ if (compressed || block_start == EXTENT_MAP_HOLE ||
+ block_start == EXTENT_MAP_INLINE) {
+ /*
+ * end_io notification does not happen here for
+ * compressed extents
+ */
+ if (!compressed && tree->ops &&
+ tree->ops->writepage_end_io_hook)
+ tree->ops->writepage_end_io_hook(page, cur,
+ cur + iosize - 1,
+ NULL, 1);
+ else if (compressed) {
+ /* we don't want to end_page_writeback on
+ * a compressed extent. this happens
+ * elsewhere
+ */
+ nr++;
+ }
+
+ cur += iosize;
+ pg_offset += iosize;
+ continue;
+ }
+
+ btrfs_set_range_writeback(tree, cur, cur + iosize - 1);
+ if (!PageWriteback(page)) {
+ btrfs_err(BTRFS_I(inode)->root->fs_info,
+ "page %lu not writeback, cur %llu end %llu",
+ page->index, cur, end);
+ }
+
+ ret = submit_extent_page(REQ_OP_WRITE | write_flags, tree, wbc,
+ page, offset, iosize, pg_offset,
+ bdev, &epd->bio,
+ end_bio_extent_writepage,
+ 0, 0, 0, false);
+ if (ret) {
+ SetPageError(page);
+ if (PageWriteback(page))
+ end_page_writeback(page);
+ }
+
+ cur = cur + iosize;
+ pg_offset += iosize;
+ nr++;
+ }
+done:
+ *nr_ret = nr;
+ return ret;
+}
+
+/*
+ * the writepage semantics are similar to regular writepage. extent
+ * records are inserted to lock ranges in the tree, and as dirty areas
+ * are found, they are marked writeback. Then the lock bits are removed
+ * and the end_io handler clears the writeback ranges
+ */
+static int __extent_writepage(struct page *page, struct writeback_control *wbc,
+ struct extent_page_data *epd)
+{
+ struct inode *inode = page->mapping->host;
+ u64 start = page_offset(page);
+ u64 page_end = start + PAGE_SIZE - 1;
+ int ret;
+ int nr = 0;
+ size_t pg_offset = 0;
+ loff_t i_size = i_size_read(inode);
+ unsigned long end_index = i_size >> PAGE_SHIFT;
+ unsigned int write_flags = 0;
+ unsigned long nr_written = 0;
+
+ write_flags = wbc_to_write_flags(wbc);
+
+ trace___extent_writepage(page, inode, wbc);
+
+ WARN_ON(!PageLocked(page));
+
+ ClearPageError(page);
+
+ pg_offset = i_size & (PAGE_SIZE - 1);
+ if (page->index > end_index ||
+ (page->index == end_index && !pg_offset)) {
+ page->mapping->a_ops->invalidatepage(page, 0, PAGE_SIZE);
+ unlock_page(page);
+ return 0;
+ }
+
+ if (page->index == end_index) {
+ char *userpage;
+
+ userpage = kmap_atomic(page);
+ memset(userpage + pg_offset, 0,
+ PAGE_SIZE - pg_offset);
+ kunmap_atomic(userpage);
+ flush_dcache_page(page);
+ }
+
+ pg_offset = 0;
+
+ set_page_extent_mapped(page);
+
+ ret = writepage_delalloc(inode, page, wbc, epd, start, &nr_written);
+ if (ret == 1)
+ goto done_unlocked;
+ if (ret)
+ goto done;
+
+ ret = __extent_writepage_io(inode, page, wbc, epd,
+ i_size, nr_written, write_flags, &nr);
+ if (ret == 1)
+ goto done_unlocked;
+
+done:
+ if (nr == 0) {
+ /* make sure the mapping tag for page dirty gets cleared */
+ set_page_writeback(page);
+ end_page_writeback(page);
+ }
+ if (PageError(page)) {
+ ret = ret < 0 ? ret : -EIO;
+ end_extent_writepage(page, ret, start, page_end);
+ }
+ unlock_page(page);
+ return ret;
+
+done_unlocked:
+ return 0;
+}
+
+void wait_on_extent_buffer_writeback(struct extent_buffer *eb)
+{
+ wait_on_bit_io(&eb->bflags, EXTENT_BUFFER_WRITEBACK,
+ TASK_UNINTERRUPTIBLE);
+}
+
+static noinline_for_stack int
+lock_extent_buffer_for_io(struct extent_buffer *eb,
+ struct btrfs_fs_info *fs_info,
+ struct extent_page_data *epd)
+{
+ int i, num_pages;
+ int flush = 0;
+ int ret = 0;
+
+ if (!btrfs_try_tree_write_lock(eb)) {
+ flush = 1;
+ flush_write_bio(epd);
+ btrfs_tree_lock(eb);
+ }
+
+ if (test_bit(EXTENT_BUFFER_WRITEBACK, &eb->bflags)) {
+ btrfs_tree_unlock(eb);
+ if (!epd->sync_io)
+ return 0;
+ if (!flush) {
+ flush_write_bio(epd);
+ flush = 1;
+ }
+ while (1) {
+ wait_on_extent_buffer_writeback(eb);
+ btrfs_tree_lock(eb);
+ if (!test_bit(EXTENT_BUFFER_WRITEBACK, &eb->bflags))
+ break;
+ btrfs_tree_unlock(eb);
+ }
+ }
+
+ /*
+ * We need to do this to prevent races in people who check if the eb is
+ * under IO since we can end up having no IO bits set for a short period
+ * of time.
+ */
+ spin_lock(&eb->refs_lock);
+ if (test_and_clear_bit(EXTENT_BUFFER_DIRTY, &eb->bflags)) {
+ set_bit(EXTENT_BUFFER_WRITEBACK, &eb->bflags);
+ spin_unlock(&eb->refs_lock);
+ btrfs_set_header_flag(eb, BTRFS_HEADER_FLAG_WRITTEN);
+ percpu_counter_add_batch(&fs_info->dirty_metadata_bytes,
+ -eb->len,
+ fs_info->dirty_metadata_batch);
+ ret = 1;
+ } else {
+ spin_unlock(&eb->refs_lock);
+ }
+
+ btrfs_tree_unlock(eb);
+
+ if (!ret)
+ return ret;
+
+ num_pages = num_extent_pages(eb);
+ for (i = 0; i < num_pages; i++) {
+ struct page *p = eb->pages[i];
+
+ if (!trylock_page(p)) {
+ if (!flush) {
+ flush_write_bio(epd);
+ flush = 1;
+ }
+ lock_page(p);
+ }
+ }
+
+ return ret;
+}
+
+static void end_extent_buffer_writeback(struct extent_buffer *eb)
+{
+ clear_bit(EXTENT_BUFFER_WRITEBACK, &eb->bflags);
+ smp_mb__after_atomic();
+ wake_up_bit(&eb->bflags, EXTENT_BUFFER_WRITEBACK);
+}
+
+static void set_btree_ioerr(struct page *page)
+{
+ struct extent_buffer *eb = (struct extent_buffer *)page->private;
+
+ SetPageError(page);
+ if (test_and_set_bit(EXTENT_BUFFER_WRITE_ERR, &eb->bflags))
+ return;
+
+ /*
+ * If writeback for a btree extent that doesn't belong to a log tree
+ * failed, increment the counter transaction->eb_write_errors.
+ * We do this because while the transaction is running and before it's
+ * committing (when we call filemap_fdata[write|wait]_range against
+ * the btree inode), we might have
+ * btree_inode->i_mapping->a_ops->writepages() called by the VM - if it
+ * returns an error or an error happens during writeback, when we're
+ * committing the transaction we wouldn't know about it, since the pages
+ * can be no longer dirty nor marked anymore for writeback (if a
+ * subsequent modification to the extent buffer didn't happen before the
+ * transaction commit), which makes filemap_fdata[write|wait]_range not
+ * able to find the pages tagged with SetPageError at transaction
+ * commit time. So if this happens we must abort the transaction,
+ * otherwise we commit a super block with btree roots that point to
+ * btree nodes/leafs whose content on disk is invalid - either garbage
+ * or the content of some node/leaf from a past generation that got
+ * cowed or deleted and is no longer valid.
+ *
+ * Note: setting AS_EIO/AS_ENOSPC in the btree inode's i_mapping would
+ * not be enough - we need to distinguish between log tree extents vs
+ * non-log tree extents, and the next filemap_fdatawait_range() call
+ * will catch and clear such errors in the mapping - and that call might
+ * be from a log sync and not from a transaction commit. Also, checking
+ * for the eb flag EXTENT_BUFFER_WRITE_ERR at transaction commit time is
+ * not done and would not be reliable - the eb might have been released
+ * from memory and reading it back again means that flag would not be
+ * set (since it's a runtime flag, not persisted on disk).
+ *
+ * Using the flags below in the btree inode also makes us achieve the
+ * goal of AS_EIO/AS_ENOSPC when writepages() returns success, started
+ * writeback for all dirty pages and before filemap_fdatawait_range()
+ * is called, the writeback for all dirty pages had already finished
+ * with errors - because we were not using AS_EIO/AS_ENOSPC,
+ * filemap_fdatawait_range() would return success, as it could not know
+ * that writeback errors happened (the pages were no longer tagged for
+ * writeback).
+ */
+ switch (eb->log_index) {
+ case -1:
+ set_bit(BTRFS_FS_BTREE_ERR, &eb->fs_info->flags);
+ break;
+ case 0:
+ set_bit(BTRFS_FS_LOG1_ERR, &eb->fs_info->flags);
+ break;
+ case 1:
+ set_bit(BTRFS_FS_LOG2_ERR, &eb->fs_info->flags);
+ break;
+ default:
+ BUG(); /* unexpected, logic error */
+ }
+}
+
+static void end_bio_extent_buffer_writepage(struct bio *bio)
+{
+ struct bio_vec *bvec;
+ struct extent_buffer *eb;
+ int i, done;
+
+ ASSERT(!bio_flagged(bio, BIO_CLONED));
+ bio_for_each_segment_all(bvec, bio, i) {
+ struct page *page = bvec->bv_page;
+
+ eb = (struct extent_buffer *)page->private;
+ BUG_ON(!eb);
+ done = atomic_dec_and_test(&eb->io_pages);
+
+ if (bio->bi_status ||
+ test_bit(EXTENT_BUFFER_WRITE_ERR, &eb->bflags)) {
+ ClearPageUptodate(page);
+ set_btree_ioerr(page);
+ }
+
+ end_page_writeback(page);
+
+ if (!done)
+ continue;
+
+ end_extent_buffer_writeback(eb);
+ }
+
+ bio_put(bio);
+}
+
+static noinline_for_stack int write_one_eb(struct extent_buffer *eb,
+ struct btrfs_fs_info *fs_info,
+ struct writeback_control *wbc,
+ struct extent_page_data *epd)
+{
+ struct block_device *bdev = fs_info->fs_devices->latest_bdev;
+ struct extent_io_tree *tree = &BTRFS_I(fs_info->btree_inode)->io_tree;
+ u64 offset = eb->start;
+ u32 nritems;
+ int i, num_pages;
+ unsigned long start, end;
+ unsigned int write_flags = wbc_to_write_flags(wbc) | REQ_META;
+ int ret = 0;
+
+ clear_bit(EXTENT_BUFFER_WRITE_ERR, &eb->bflags);
+ num_pages = num_extent_pages(eb);
+ atomic_set(&eb->io_pages, num_pages);
+
+ /* set btree blocks beyond nritems with 0 to avoid stale content. */
+ nritems = btrfs_header_nritems(eb);
+ if (btrfs_header_level(eb) > 0) {
+ end = btrfs_node_key_ptr_offset(nritems);
+
+ memzero_extent_buffer(eb, end, eb->len - end);
+ } else {
+ /*
+ * leaf:
+ * header 0 1 2 .. N ... data_N .. data_2 data_1 data_0
+ */
+ start = btrfs_item_nr_offset(nritems);
+ end = BTRFS_LEAF_DATA_OFFSET + leaf_data_end(fs_info, eb);
+ memzero_extent_buffer(eb, start, end - start);
+ }
+
+ for (i = 0; i < num_pages; i++) {
+ struct page *p = eb->pages[i];
+
+ clear_page_dirty_for_io(p);
+ set_page_writeback(p);
+ ret = submit_extent_page(REQ_OP_WRITE | write_flags, tree, wbc,
+ p, offset, PAGE_SIZE, 0, bdev,
+ &epd->bio,
+ end_bio_extent_buffer_writepage,
+ 0, 0, 0, false);
+ if (ret) {
+ set_btree_ioerr(p);
+ if (PageWriteback(p))
+ end_page_writeback(p);
+ if (atomic_sub_and_test(num_pages - i, &eb->io_pages))
+ end_extent_buffer_writeback(eb);
+ ret = -EIO;
+ break;
+ }
+ offset += PAGE_SIZE;
+ update_nr_written(wbc, 1);
+ unlock_page(p);
+ }
+
+ if (unlikely(ret)) {
+ for (; i < num_pages; i++) {
+ struct page *p = eb->pages[i];
+ clear_page_dirty_for_io(p);
+ unlock_page(p);
+ }
+ }
+
+ return ret;
+}
+
+int btree_write_cache_pages(struct address_space *mapping,
+ struct writeback_control *wbc)
+{
+ struct extent_io_tree *tree = &BTRFS_I(mapping->host)->io_tree;
+ struct btrfs_fs_info *fs_info = BTRFS_I(mapping->host)->root->fs_info;
+ struct extent_buffer *eb, *prev_eb = NULL;
+ struct extent_page_data epd = {
+ .bio = NULL,
+ .tree = tree,
+ .extent_locked = 0,
+ .sync_io = wbc->sync_mode == WB_SYNC_ALL,
+ };
+ int ret = 0;
+ int done = 0;
+ int nr_to_write_done = 0;
+ struct pagevec pvec;
+ int nr_pages;
+ pgoff_t index;
+ pgoff_t end; /* Inclusive */
+ int scanned = 0;
+ int tag;
+
+ pagevec_init(&pvec);
+ if (wbc->range_cyclic) {
+ index = mapping->writeback_index; /* Start from prev offset */
+ end = -1;
+ } else {
+ index = wbc->range_start >> PAGE_SHIFT;
+ end = wbc->range_end >> PAGE_SHIFT;
+ scanned = 1;
+ }
+ if (wbc->sync_mode == WB_SYNC_ALL)
+ tag = PAGECACHE_TAG_TOWRITE;
+ else
+ tag = PAGECACHE_TAG_DIRTY;
+retry:
+ if (wbc->sync_mode == WB_SYNC_ALL)
+ tag_pages_for_writeback(mapping, index, end);
+ while (!done && !nr_to_write_done && (index <= end) &&
+ (nr_pages = pagevec_lookup_range_tag(&pvec, mapping, &index, end,
+ tag))) {
+ unsigned i;
+
+ scanned = 1;
+ for (i = 0; i < nr_pages; i++) {
+ struct page *page = pvec.pages[i];
+
+ if (!PagePrivate(page))
+ continue;
+
+ spin_lock(&mapping->private_lock);
+ if (!PagePrivate(page)) {
+ spin_unlock(&mapping->private_lock);
+ continue;
+ }
+
+ eb = (struct extent_buffer *)page->private;
+
+ /*
+ * Shouldn't happen and normally this would be a BUG_ON
+ * but no sense in crashing the users box for something
+ * we can survive anyway.
+ */
+ if (WARN_ON(!eb)) {
+ spin_unlock(&mapping->private_lock);
+ continue;
+ }
+
+ if (eb == prev_eb) {
+ spin_unlock(&mapping->private_lock);
+ continue;
+ }
+
+ ret = atomic_inc_not_zero(&eb->refs);
+ spin_unlock(&mapping->private_lock);
+ if (!ret)
+ continue;
+
+ prev_eb = eb;
+ ret = lock_extent_buffer_for_io(eb, fs_info, &epd);
+ if (!ret) {
+ free_extent_buffer(eb);
+ continue;
+ }
+
+ ret = write_one_eb(eb, fs_info, wbc, &epd);
+ if (ret) {
+ done = 1;
+ free_extent_buffer(eb);
+ break;
+ }
+ free_extent_buffer(eb);
+
+ /*
+ * the filesystem may choose to bump up nr_to_write.
+ * We have to make sure to honor the new nr_to_write
+ * at any time
+ */
+ nr_to_write_done = wbc->nr_to_write <= 0;
+ }
+ pagevec_release(&pvec);
+ cond_resched();
+ }
+ if (!scanned && !done) {
+ /*
+ * We hit the last page and there is more work to be done: wrap
+ * back to the start of the file
+ */
+ scanned = 1;
+ index = 0;
+ goto retry;
+ }
+ flush_write_bio(&epd);
+ return ret;
+}
+
+/**
+ * write_cache_pages - walk the list of dirty pages of the given address space and write all of them.
+ * @mapping: address space structure to write
+ * @wbc: subtract the number of written pages from *@wbc->nr_to_write
+ * @data: data passed to __extent_writepage function
+ *
+ * If a page is already under I/O, write_cache_pages() skips it, even
+ * if it's dirty. This is desirable behaviour for memory-cleaning writeback,
+ * but it is INCORRECT for data-integrity system calls such as fsync(). fsync()
+ * and msync() need to guarantee that all the data which was dirty at the time
+ * the call was made get new I/O started against them. If wbc->sync_mode is
+ * WB_SYNC_ALL then we were called for data integrity and we must wait for
+ * existing IO to complete.
+ */
+static int extent_write_cache_pages(struct address_space *mapping,
+ struct writeback_control *wbc,
+ struct extent_page_data *epd)
+{
+ struct inode *inode = mapping->host;
+ int ret = 0;
+ int done = 0;
+ int nr_to_write_done = 0;
+ struct pagevec pvec;
+ int nr_pages;
+ pgoff_t index;
+ pgoff_t end; /* Inclusive */
+ pgoff_t done_index;
+ int range_whole = 0;
+ int scanned = 0;
+ int tag;
+
+ /*
+ * We have to hold onto the inode so that ordered extents can do their
+ * work when the IO finishes. The alternative to this is failing to add
+ * an ordered extent if the igrab() fails there and that is a huge pain
+ * to deal with, so instead just hold onto the inode throughout the
+ * writepages operation. If it fails here we are freeing up the inode
+ * anyway and we'd rather not waste our time writing out stuff that is
+ * going to be truncated anyway.
+ */
+ if (!igrab(inode))
+ return 0;
+
+ pagevec_init(&pvec);
+ if (wbc->range_cyclic) {
+ index = mapping->writeback_index; /* Start from prev offset */
+ end = -1;
+ } else {
+ index = wbc->range_start >> PAGE_SHIFT;
+ end = wbc->range_end >> PAGE_SHIFT;
+ if (wbc->range_start == 0 && wbc->range_end == LLONG_MAX)
+ range_whole = 1;
+ scanned = 1;
+ }
+ if (wbc->sync_mode == WB_SYNC_ALL)
+ tag = PAGECACHE_TAG_TOWRITE;
+ else
+ tag = PAGECACHE_TAG_DIRTY;
+retry:
+ if (wbc->sync_mode == WB_SYNC_ALL)
+ tag_pages_for_writeback(mapping, index, end);
+ done_index = index;
+ while (!done && !nr_to_write_done && (index <= end) &&
+ (nr_pages = pagevec_lookup_range_tag(&pvec, mapping,
+ &index, end, tag))) {
+ unsigned i;
+
+ scanned = 1;
+ for (i = 0; i < nr_pages; i++) {
+ struct page *page = pvec.pages[i];
+
+ done_index = page->index;
+ /*
+ * At this point we hold neither the i_pages lock nor
+ * the page lock: the page may be truncated or
+ * invalidated (changing page->mapping to NULL),
+ * or even swizzled back from swapper_space to
+ * tmpfs file mapping
+ */
+ if (!trylock_page(page)) {
+ flush_write_bio(epd);
+ lock_page(page);
+ }
+
+ if (unlikely(page->mapping != mapping)) {
+ unlock_page(page);
+ continue;
+ }
+
+ if (wbc->sync_mode != WB_SYNC_NONE) {
+ if (PageWriteback(page))
+ flush_write_bio(epd);
+ wait_on_page_writeback(page);
+ }
+
+ if (PageWriteback(page) ||
+ !clear_page_dirty_for_io(page)) {
+ unlock_page(page);
+ continue;
+ }
+
+ ret = __extent_writepage(page, wbc, epd);
+
+ if (unlikely(ret == AOP_WRITEPAGE_ACTIVATE)) {
+ unlock_page(page);
+ ret = 0;
+ }
+ if (ret < 0) {
+ /*
+ * done_index is set past this page,
+ * so media errors will not choke
+ * background writeout for the entire
+ * file. This has consequences for
+ * range_cyclic semantics (ie. it may
+ * not be suitable for data integrity
+ * writeout).
+ */
+ done_index = page->index + 1;
+ done = 1;
+ break;
+ }
+
+ /*
+ * the filesystem may choose to bump up nr_to_write.
+ * We have to make sure to honor the new nr_to_write
+ * at any time
+ */
+ nr_to_write_done = wbc->nr_to_write <= 0;
+ }
+ pagevec_release(&pvec);
+ cond_resched();
+ }
+ if (!scanned && !done) {
+ /*
+ * We hit the last page and there is more work to be done: wrap
+ * back to the start of the file
+ */
+ scanned = 1;
+ index = 0;
+ goto retry;
+ }
+
+ if (wbc->range_cyclic || (wbc->nr_to_write > 0 && range_whole))
+ mapping->writeback_index = done_index;
+
+ btrfs_add_delayed_iput(inode);
+ return ret;
+}
+
+static void flush_write_bio(struct extent_page_data *epd)
+{
+ if (epd->bio) {
+ int ret;
+
+ ret = submit_one_bio(epd->bio, 0, 0);
+ BUG_ON(ret < 0); /* -ENOMEM */
+ epd->bio = NULL;
+ }
+}
+
+int extent_write_full_page(struct page *page, struct writeback_control *wbc)
+{
+ int ret;
+ struct extent_page_data epd = {
+ .bio = NULL,
+ .tree = &BTRFS_I(page->mapping->host)->io_tree,
+ .extent_locked = 0,
+ .sync_io = wbc->sync_mode == WB_SYNC_ALL,
+ };
+
+ ret = __extent_writepage(page, wbc, &epd);
+
+ flush_write_bio(&epd);
+ return ret;
+}
+
+int extent_write_locked_range(struct inode *inode, u64 start, u64 end,
+ int mode)
+{
+ int ret = 0;
+ struct address_space *mapping = inode->i_mapping;
+ struct extent_io_tree *tree = &BTRFS_I(inode)->io_tree;
+ struct page *page;
+ unsigned long nr_pages = (end - start + PAGE_SIZE) >>
+ PAGE_SHIFT;
+
+ struct extent_page_data epd = {
+ .bio = NULL,
+ .tree = tree,
+ .extent_locked = 1,
+ .sync_io = mode == WB_SYNC_ALL,
+ };
+ struct writeback_control wbc_writepages = {
+ .sync_mode = mode,
+ .nr_to_write = nr_pages * 2,
+ .range_start = start,
+ .range_end = end + 1,
+ };
+
+ while (start <= end) {
+ page = find_get_page(mapping, start >> PAGE_SHIFT);
+ if (clear_page_dirty_for_io(page))
+ ret = __extent_writepage(page, &wbc_writepages, &epd);
+ else {
+ if (tree->ops && tree->ops->writepage_end_io_hook)
+ tree->ops->writepage_end_io_hook(page, start,
+ start + PAGE_SIZE - 1,
+ NULL, 1);
+ unlock_page(page);
+ }
+ put_page(page);
+ start += PAGE_SIZE;
+ }
+
+ flush_write_bio(&epd);
+ return ret;
+}
+
+int extent_writepages(struct address_space *mapping,
+ struct writeback_control *wbc)
+{
+ int ret = 0;
+ struct extent_page_data epd = {
+ .bio = NULL,
+ .tree = &BTRFS_I(mapping->host)->io_tree,
+ .extent_locked = 0,
+ .sync_io = wbc->sync_mode == WB_SYNC_ALL,
+ };
+
+ ret = extent_write_cache_pages(mapping, wbc, &epd);
+ flush_write_bio(&epd);
+ return ret;
+}
+
+int extent_readpages(struct address_space *mapping, struct list_head *pages,
+ unsigned nr_pages)
+{
+ struct bio *bio = NULL;
+ unsigned page_idx;
+ unsigned long bio_flags = 0;
+ struct page *pagepool[16];
+ struct page *page;
+ struct extent_map *em_cached = NULL;
+ struct extent_io_tree *tree = &BTRFS_I(mapping->host)->io_tree;
+ int nr = 0;
+ u64 prev_em_start = (u64)-1;
+
+ for (page_idx = 0; page_idx < nr_pages; page_idx++) {
+ page = list_entry(pages->prev, struct page, lru);
+
+ prefetchw(&page->flags);
+ list_del(&page->lru);
+ if (add_to_page_cache_lru(page, mapping,
+ page->index,
+ readahead_gfp_mask(mapping))) {
+ put_page(page);
+ continue;
+ }
+
+ pagepool[nr++] = page;
+ if (nr < ARRAY_SIZE(pagepool))
+ continue;
+ __extent_readpages(tree, pagepool, nr, &em_cached, &bio,
+ &bio_flags, &prev_em_start);
+ nr = 0;
+ }
+ if (nr)
+ __extent_readpages(tree, pagepool, nr, &em_cached, &bio,
+ &bio_flags, &prev_em_start);
+
+ if (em_cached)
+ free_extent_map(em_cached);
+
+ BUG_ON(!list_empty(pages));
+ if (bio)
+ return submit_one_bio(bio, 0, bio_flags);
+ return 0;
+}
+
+/*
+ * basic invalidatepage code, this waits on any locked or writeback
+ * ranges corresponding to the page, and then deletes any extent state
+ * records from the tree
+ */
+int extent_invalidatepage(struct extent_io_tree *tree,
+ struct page *page, unsigned long offset)
+{
+ struct extent_state *cached_state = NULL;
+ u64 start = page_offset(page);
+ u64 end = start + PAGE_SIZE - 1;
+ size_t blocksize = page->mapping->host->i_sb->s_blocksize;
+
+ start += ALIGN(offset, blocksize);
+ if (start > end)
+ return 0;
+
+ lock_extent_bits(tree, start, end, &cached_state);
+ wait_on_page_writeback(page);
+ clear_extent_bit(tree, start, end,
+ EXTENT_LOCKED | EXTENT_DIRTY | EXTENT_DELALLOC |
+ EXTENT_DO_ACCOUNTING,
+ 1, 1, &cached_state);
+ return 0;
+}
+
+/*
+ * a helper for releasepage, this tests for areas of the page that
+ * are locked or under IO and drops the related state bits if it is safe
+ * to drop the page.
+ */
+static int try_release_extent_state(struct extent_io_tree *tree,
+ struct page *page, gfp_t mask)
+{
+ u64 start = page_offset(page);
+ u64 end = start + PAGE_SIZE - 1;
+ int ret = 1;
+
+ if (test_range_bit(tree, start, end,
+ EXTENT_IOBITS, 0, NULL))
+ ret = 0;
+ else {
+ /*
+ * at this point we can safely clear everything except the
+ * locked bit and the nodatasum bit
+ */
+ ret = __clear_extent_bit(tree, start, end,
+ ~(EXTENT_LOCKED | EXTENT_NODATASUM),
+ 0, 0, NULL, mask, NULL);
+
+ /* if clear_extent_bit failed for enomem reasons,
+ * we can't allow the release to continue.
+ */
+ if (ret < 0)
+ ret = 0;
+ else
+ ret = 1;
+ }
+ return ret;
+}
+
+/*
+ * a helper for releasepage. As long as there are no locked extents
+ * in the range corresponding to the page, both state records and extent
+ * map records are removed
+ */
+int try_release_extent_mapping(struct page *page, gfp_t mask)
+{
+ struct extent_map *em;
+ u64 start = page_offset(page);
+ u64 end = start + PAGE_SIZE - 1;
+ struct btrfs_inode *btrfs_inode = BTRFS_I(page->mapping->host);
+ struct extent_io_tree *tree = &btrfs_inode->io_tree;
+ struct extent_map_tree *map = &btrfs_inode->extent_tree;
+
+ if (gfpflags_allow_blocking(mask) &&
+ page->mapping->host->i_size > SZ_16M) {
+ u64 len;
+ while (start <= end) {
+ len = end - start + 1;
+ write_lock(&map->lock);
+ em = lookup_extent_mapping(map, start, len);
+ if (!em) {
+ write_unlock(&map->lock);
+ break;
+ }
+ if (test_bit(EXTENT_FLAG_PINNED, &em->flags) ||
+ em->start != start) {
+ write_unlock(&map->lock);
+ free_extent_map(em);
+ break;
+ }
+ if (!test_range_bit(tree, em->start,
+ extent_map_end(em) - 1,
+ EXTENT_LOCKED | EXTENT_WRITEBACK,
+ 0, NULL)) {
+ set_bit(BTRFS_INODE_NEEDS_FULL_SYNC,
+ &btrfs_inode->runtime_flags);
+ remove_extent_mapping(map, em);
+ /* once for the rb tree */
+ free_extent_map(em);
+ }
+ start = extent_map_end(em);
+ write_unlock(&map->lock);
+
+ /* once for us */
+ free_extent_map(em);
+ }
+ }
+ return try_release_extent_state(tree, page, mask);
+}
+
+/*
+ * helper function for fiemap, which doesn't want to see any holes.
+ * This maps until we find something past 'last'
+ */
+static struct extent_map *get_extent_skip_holes(struct inode *inode,
+ u64 offset, u64 last)
+{
+ u64 sectorsize = btrfs_inode_sectorsize(inode);
+ struct extent_map *em;
+ u64 len;
+
+ if (offset >= last)
+ return NULL;
+
+ while (1) {
+ len = last - offset;
+ if (len == 0)
+ break;
+ len = ALIGN(len, sectorsize);
+ em = btrfs_get_extent_fiemap(BTRFS_I(inode), NULL, 0, offset,
+ len, 0);
+ if (IS_ERR_OR_NULL(em))
+ return em;
+
+ /* if this isn't a hole return it */
+ if (em->block_start != EXTENT_MAP_HOLE)
+ return em;
+
+ /* this is a hole, advance to the next extent */
+ offset = extent_map_end(em);
+ free_extent_map(em);
+ if (offset >= last)
+ break;
+ }
+ return NULL;
+}
+
+/*
+ * To cache previous fiemap extent
+ *
+ * Will be used for merging fiemap extent
+ */
+struct fiemap_cache {
+ u64 offset;
+ u64 phys;
+ u64 len;
+ u32 flags;
+ bool cached;
+};
+
+/*
+ * Helper to submit fiemap extent.
+ *
+ * Will try to merge current fiemap extent specified by @offset, @phys,
+ * @len and @flags with cached one.
+ * And only when we fails to merge, cached one will be submitted as
+ * fiemap extent.
+ *
+ * Return value is the same as fiemap_fill_next_extent().
+ */
+static int emit_fiemap_extent(struct fiemap_extent_info *fieinfo,
+ struct fiemap_cache *cache,
+ u64 offset, u64 phys, u64 len, u32 flags)
+{
+ int ret = 0;
+
+ if (!cache->cached)
+ goto assign;
+
+ /*
+ * Sanity check, extent_fiemap() should have ensured that new
+ * fiemap extent won't overlap with cahced one.
+ * Not recoverable.
+ *
+ * NOTE: Physical address can overlap, due to compression
+ */
+ if (cache->offset + cache->len > offset) {
+ WARN_ON(1);
+ return -EINVAL;
+ }
+
+ /*
+ * Only merges fiemap extents if
+ * 1) Their logical addresses are continuous
+ *
+ * 2) Their physical addresses are continuous
+ * So truly compressed (physical size smaller than logical size)
+ * extents won't get merged with each other
+ *
+ * 3) Share same flags except FIEMAP_EXTENT_LAST
+ * So regular extent won't get merged with prealloc extent
+ */
+ if (cache->offset + cache->len == offset &&
+ cache->phys + cache->len == phys &&
+ (cache->flags & ~FIEMAP_EXTENT_LAST) ==
+ (flags & ~FIEMAP_EXTENT_LAST)) {
+ cache->len += len;
+ cache->flags |= flags;
+ goto try_submit_last;
+ }
+
+ /* Not mergeable, need to submit cached one */
+ ret = fiemap_fill_next_extent(fieinfo, cache->offset, cache->phys,
+ cache->len, cache->flags);
+ cache->cached = false;
+ if (ret)
+ return ret;
+assign:
+ cache->cached = true;
+ cache->offset = offset;
+ cache->phys = phys;
+ cache->len = len;
+ cache->flags = flags;
+try_submit_last:
+ if (cache->flags & FIEMAP_EXTENT_LAST) {
+ ret = fiemap_fill_next_extent(fieinfo, cache->offset,
+ cache->phys, cache->len, cache->flags);
+ cache->cached = false;
+ }
+ return ret;
+}
+
+/*
+ * Emit last fiemap cache
+ *
+ * The last fiemap cache may still be cached in the following case:
+ * 0 4k 8k
+ * |<- Fiemap range ->|
+ * |<------------ First extent ----------->|
+ *
+ * In this case, the first extent range will be cached but not emitted.
+ * So we must emit it before ending extent_fiemap().
+ */
+static int emit_last_fiemap_cache(struct btrfs_fs_info *fs_info,
+ struct fiemap_extent_info *fieinfo,
+ struct fiemap_cache *cache)
+{
+ int ret;
+
+ if (!cache->cached)
+ return 0;
+
+ ret = fiemap_fill_next_extent(fieinfo, cache->offset, cache->phys,
+ cache->len, cache->flags);
+ cache->cached = false;
+ if (ret > 0)
+ ret = 0;
+ return ret;
+}
+
+int extent_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
+ __u64 start, __u64 len)
+{
+ int ret = 0;
+ u64 off = start;
+ u64 max = start + len;
+ u32 flags = 0;
+ u32 found_type;
+ u64 last;
+ u64 last_for_get_extent = 0;
+ u64 disko = 0;
+ u64 isize = i_size_read(inode);
+ struct btrfs_key found_key;
+ struct extent_map *em = NULL;
+ struct extent_state *cached_state = NULL;
+ struct btrfs_path *path;
+ struct btrfs_root *root = BTRFS_I(inode)->root;
+ struct fiemap_cache cache = { 0 };
+ int end = 0;
+ u64 em_start = 0;
+ u64 em_len = 0;
+ u64 em_end = 0;
+
+ if (len == 0)
+ return -EINVAL;
+
+ path = btrfs_alloc_path();
+ if (!path)
+ return -ENOMEM;
+ path->leave_spinning = 1;
+
+ start = round_down(start, btrfs_inode_sectorsize(inode));
+ len = round_up(max, btrfs_inode_sectorsize(inode)) - start;
+
+ /*
+ * lookup the last file extent. We're not using i_size here
+ * because there might be preallocation past i_size
+ */
+ ret = btrfs_lookup_file_extent(NULL, root, path,
+ btrfs_ino(BTRFS_I(inode)), -1, 0);
+ if (ret < 0) {
+ btrfs_free_path(path);
+ return ret;
+ } else {
+ WARN_ON(!ret);
+ if (ret == 1)
+ ret = 0;
+ }
+
+ path->slots[0]--;
+ btrfs_item_key_to_cpu(path->nodes[0], &found_key, path->slots[0]);
+ found_type = found_key.type;
+
+ /* No extents, but there might be delalloc bits */
+ if (found_key.objectid != btrfs_ino(BTRFS_I(inode)) ||
+ found_type != BTRFS_EXTENT_DATA_KEY) {
+ /* have to trust i_size as the end */
+ last = (u64)-1;
+ last_for_get_extent = isize;
+ } else {
+ /*
+ * remember the start of the last extent. There are a
+ * bunch of different factors that go into the length of the
+ * extent, so its much less complex to remember where it started
+ */
+ last = found_key.offset;
+ last_for_get_extent = last + 1;
+ }
+ btrfs_release_path(path);
+
+ /*
+ * we might have some extents allocated but more delalloc past those
+ * extents. so, we trust isize unless the start of the last extent is
+ * beyond isize
+ */
+ if (last < isize) {
+ last = (u64)-1;
+ last_for_get_extent = isize;
+ }
+
+ lock_extent_bits(&BTRFS_I(inode)->io_tree, start, start + len - 1,
+ &cached_state);
+
+ em = get_extent_skip_holes(inode, start, last_for_get_extent);
+ if (!em)
+ goto out;
+ if (IS_ERR(em)) {
+ ret = PTR_ERR(em);
+ goto out;
+ }
+
+ while (!end) {
+ u64 offset_in_extent = 0;
+
+ /* break if the extent we found is outside the range */
+ if (em->start >= max || extent_map_end(em) < off)
+ break;
+
+ /*
+ * get_extent may return an extent that starts before our
+ * requested range. We have to make sure the ranges
+ * we return to fiemap always move forward and don't
+ * overlap, so adjust the offsets here
+ */
+ em_start = max(em->start, off);
+
+ /*
+ * record the offset from the start of the extent
+ * for adjusting the disk offset below. Only do this if the
+ * extent isn't compressed since our in ram offset may be past
+ * what we have actually allocated on disk.
+ */
+ if (!test_bit(EXTENT_FLAG_COMPRESSED, &em->flags))
+ offset_in_extent = em_start - em->start;
+ em_end = extent_map_end(em);
+ em_len = em_end - em_start;
+ flags = 0;
+ if (em->block_start < EXTENT_MAP_LAST_BYTE)
+ disko = em->block_start + offset_in_extent;
+ else
+ disko = 0;
+
+ /*
+ * bump off for our next call to get_extent
+ */
+ off = extent_map_end(em);
+ if (off >= max)
+ end = 1;
+
+ if (em->block_start == EXTENT_MAP_LAST_BYTE) {
+ end = 1;
+ flags |= FIEMAP_EXTENT_LAST;
+ } else if (em->block_start == EXTENT_MAP_INLINE) {
+ flags |= (FIEMAP_EXTENT_DATA_INLINE |
+ FIEMAP_EXTENT_NOT_ALIGNED);
+ } else if (em->block_start == EXTENT_MAP_DELALLOC) {
+ flags |= (FIEMAP_EXTENT_DELALLOC |
+ FIEMAP_EXTENT_UNKNOWN);
+ } else if (fieinfo->fi_extents_max) {
+ u64 bytenr = em->block_start -
+ (em->start - em->orig_start);
+
+ /*
+ * As btrfs supports shared space, this information
+ * can be exported to userspace tools via
+ * flag FIEMAP_EXTENT_SHARED. If fi_extents_max == 0
+ * then we're just getting a count and we can skip the
+ * lookup stuff.
+ */
+ ret = btrfs_check_shared(root,
+ btrfs_ino(BTRFS_I(inode)),
+ bytenr);
+ if (ret < 0)
+ goto out_free;
+ if (ret)
+ flags |= FIEMAP_EXTENT_SHARED;
+ ret = 0;
+ }
+ if (test_bit(EXTENT_FLAG_COMPRESSED, &em->flags))
+ flags |= FIEMAP_EXTENT_ENCODED;
+ if (test_bit(EXTENT_FLAG_PREALLOC, &em->flags))
+ flags |= FIEMAP_EXTENT_UNWRITTEN;
+
+ free_extent_map(em);
+ em = NULL;
+ if ((em_start >= last) || em_len == (u64)-1 ||
+ (last == (u64)-1 && isize <= em_end)) {
+ flags |= FIEMAP_EXTENT_LAST;
+ end = 1;
+ }
+
+ /* now scan forward to see if this is really the last extent. */
+ em = get_extent_skip_holes(inode, off, last_for_get_extent);
+ if (IS_ERR(em)) {
+ ret = PTR_ERR(em);
+ goto out;
+ }
+ if (!em) {
+ flags |= FIEMAP_EXTENT_LAST;
+ end = 1;
+ }
+ ret = emit_fiemap_extent(fieinfo, &cache, em_start, disko,
+ em_len, flags);
+ if (ret) {
+ if (ret == 1)
+ ret = 0;
+ goto out_free;
+ }
+ }
+out_free:
+ if (!ret)
+ ret = emit_last_fiemap_cache(root->fs_info, fieinfo, &cache);
+ free_extent_map(em);
+out:
+ btrfs_free_path(path);
+ unlock_extent_cached(&BTRFS_I(inode)->io_tree, start, start + len - 1,
+ &cached_state);
+ return ret;
+}
+
+static void __free_extent_buffer(struct extent_buffer *eb)
+{
+ btrfs_leak_debug_del(&eb->leak_list);
+ kmem_cache_free(extent_buffer_cache, eb);
+}
+
+int extent_buffer_under_io(struct extent_buffer *eb)
+{
+ return (atomic_read(&eb->io_pages) ||
+ test_bit(EXTENT_BUFFER_WRITEBACK, &eb->bflags) ||
+ test_bit(EXTENT_BUFFER_DIRTY, &eb->bflags));
+}
+
+/*
+ * Release all pages attached to the extent buffer.
+ */
+static void btrfs_release_extent_buffer_pages(struct extent_buffer *eb)
+{
+ int i;
+ int num_pages;
+ int mapped = !test_bit(EXTENT_BUFFER_UNMAPPED, &eb->bflags);
+
+ BUG_ON(extent_buffer_under_io(eb));
+
+ num_pages = num_extent_pages(eb);
+ for (i = 0; i < num_pages; i++) {
+ struct page *page = eb->pages[i];
+
+ if (!page)
+ continue;
+ if (mapped)
+ spin_lock(&page->mapping->private_lock);
+ /*
+ * We do this since we'll remove the pages after we've
+ * removed the eb from the radix tree, so we could race
+ * and have this page now attached to the new eb. So
+ * only clear page_private if it's still connected to
+ * this eb.
+ */
+ if (PagePrivate(page) &&
+ page->private == (unsigned long)eb) {
+ BUG_ON(test_bit(EXTENT_BUFFER_DIRTY, &eb->bflags));
+ BUG_ON(PageDirty(page));
+ BUG_ON(PageWriteback(page));
+ /*
+ * We need to make sure we haven't be attached
+ * to a new eb.
+ */
+ ClearPagePrivate(page);
+ set_page_private(page, 0);
+ /* One for the page private */
+ put_page(page);
+ }
+
+ if (mapped)
+ spin_unlock(&page->mapping->private_lock);
+
+ /* One for when we allocated the page */
+ put_page(page);
+ }
+}
+
+/*
+ * Helper for releasing the extent buffer.
+ */
+static inline void btrfs_release_extent_buffer(struct extent_buffer *eb)
+{
+ btrfs_release_extent_buffer_pages(eb);
+ __free_extent_buffer(eb);
+}
+
+static struct extent_buffer *
+__alloc_extent_buffer(struct btrfs_fs_info *fs_info, u64 start,
+ unsigned long len)
+{
+ struct extent_buffer *eb = NULL;
+
+ eb = kmem_cache_zalloc(extent_buffer_cache, GFP_NOFS|__GFP_NOFAIL);
+ eb->start = start;
+ eb->len = len;
+ eb->fs_info = fs_info;
+ eb->bflags = 0;
+ rwlock_init(&eb->lock);
+ atomic_set(&eb->write_locks, 0);
+ atomic_set(&eb->read_locks, 0);
+ atomic_set(&eb->blocking_readers, 0);
+ atomic_set(&eb->blocking_writers, 0);
+ atomic_set(&eb->spinning_readers, 0);
+ atomic_set(&eb->spinning_writers, 0);
+ eb->lock_nested = 0;
+ init_waitqueue_head(&eb->write_lock_wq);
+ init_waitqueue_head(&eb->read_lock_wq);
+
+ btrfs_leak_debug_add(&eb->leak_list, &buffers);
+
+ spin_lock_init(&eb->refs_lock);
+ atomic_set(&eb->refs, 1);
+ atomic_set(&eb->io_pages, 0);
+
+ /*
+ * Sanity checks, currently the maximum is 64k covered by 16x 4k pages
+ */
+ BUILD_BUG_ON(BTRFS_MAX_METADATA_BLOCKSIZE
+ > MAX_INLINE_EXTENT_BUFFER_SIZE);
+ BUG_ON(len > MAX_INLINE_EXTENT_BUFFER_SIZE);
+
+ return eb;
+}
+
+struct extent_buffer *btrfs_clone_extent_buffer(struct extent_buffer *src)
+{
+ int i;
+ struct page *p;
+ struct extent_buffer *new;
+ int num_pages = num_extent_pages(src);
+
+ new = __alloc_extent_buffer(src->fs_info, src->start, src->len);
+ if (new == NULL)
+ return NULL;
+
+ for (i = 0; i < num_pages; i++) {
+ p = alloc_page(GFP_NOFS);
+ if (!p) {
+ btrfs_release_extent_buffer(new);
+ return NULL;
+ }
+ attach_extent_buffer_page(new, p);
+ WARN_ON(PageDirty(p));
+ SetPageUptodate(p);
+ new->pages[i] = p;
+ copy_page(page_address(p), page_address(src->pages[i]));
+ }
+
+ set_bit(EXTENT_BUFFER_UPTODATE, &new->bflags);
+ set_bit(EXTENT_BUFFER_UNMAPPED, &new->bflags);
+
+ return new;
+}
+
+struct extent_buffer *__alloc_dummy_extent_buffer(struct btrfs_fs_info *fs_info,
+ u64 start, unsigned long len)
+{
+ struct extent_buffer *eb;
+ int num_pages;
+ int i;
+
+ eb = __alloc_extent_buffer(fs_info, start, len);
+ if (!eb)
+ return NULL;
+
+ num_pages = num_extent_pages(eb);
+ for (i = 0; i < num_pages; i++) {
+ eb->pages[i] = alloc_page(GFP_NOFS);
+ if (!eb->pages[i])
+ goto err;
+ }
+ set_extent_buffer_uptodate(eb);
+ btrfs_set_header_nritems(eb, 0);
+ set_bit(EXTENT_BUFFER_UNMAPPED, &eb->bflags);
+
+ return eb;
+err:
+ for (; i > 0; i--)
+ __free_page(eb->pages[i - 1]);
+ __free_extent_buffer(eb);
+ return NULL;
+}
+
+struct extent_buffer *alloc_dummy_extent_buffer(struct btrfs_fs_info *fs_info,
+ u64 start)
+{
+ return __alloc_dummy_extent_buffer(fs_info, start, fs_info->nodesize);
+}
+
+static void check_buffer_tree_ref(struct extent_buffer *eb)
+{
+ int refs;
+ /* the ref bit is tricky. We have to make sure it is set
+ * if we have the buffer dirty. Otherwise the
+ * code to free a buffer can end up dropping a dirty
+ * page
+ *
+ * Once the ref bit is set, it won't go away while the
+ * buffer is dirty or in writeback, and it also won't
+ * go away while we have the reference count on the
+ * eb bumped.
+ *
+ * We can't just set the ref bit without bumping the
+ * ref on the eb because free_extent_buffer might
+ * see the ref bit and try to clear it. If this happens
+ * free_extent_buffer might end up dropping our original
+ * ref by mistake and freeing the page before we are able
+ * to add one more ref.
+ *
+ * So bump the ref count first, then set the bit. If someone
+ * beat us to it, drop the ref we added.
+ */
+ refs = atomic_read(&eb->refs);
+ if (refs >= 2 && test_bit(EXTENT_BUFFER_TREE_REF, &eb->bflags))
+ return;
+
+ spin_lock(&eb->refs_lock);
+ if (!test_and_set_bit(EXTENT_BUFFER_TREE_REF, &eb->bflags))
+ atomic_inc(&eb->refs);
+ spin_unlock(&eb->refs_lock);
+}
+
+static void mark_extent_buffer_accessed(struct extent_buffer *eb,
+ struct page *accessed)
+{
+ int num_pages, i;
+
+ check_buffer_tree_ref(eb);
+
+ num_pages = num_extent_pages(eb);
+ for (i = 0; i < num_pages; i++) {
+ struct page *p = eb->pages[i];
+
+ if (p != accessed)
+ mark_page_accessed(p);
+ }
+}
+
+struct extent_buffer *find_extent_buffer(struct btrfs_fs_info *fs_info,
+ u64 start)
+{
+ struct extent_buffer *eb;
+
+ rcu_read_lock();
+ eb = radix_tree_lookup(&fs_info->buffer_radix,
+ start >> PAGE_SHIFT);
+ if (eb && atomic_inc_not_zero(&eb->refs)) {
+ rcu_read_unlock();
+ /*
+ * Lock our eb's refs_lock to avoid races with
+ * free_extent_buffer. When we get our eb it might be flagged
+ * with EXTENT_BUFFER_STALE and another task running
+ * free_extent_buffer might have seen that flag set,
+ * eb->refs == 2, that the buffer isn't under IO (dirty and
+ * writeback flags not set) and it's still in the tree (flag
+ * EXTENT_BUFFER_TREE_REF set), therefore being in the process
+ * of decrementing the extent buffer's reference count twice.
+ * So here we could race and increment the eb's reference count,
+ * clear its stale flag, mark it as dirty and drop our reference
+ * before the other task finishes executing free_extent_buffer,
+ * which would later result in an attempt to free an extent
+ * buffer that is dirty.
+ */
+ if (test_bit(EXTENT_BUFFER_STALE, &eb->bflags)) {
+ spin_lock(&eb->refs_lock);
+ spin_unlock(&eb->refs_lock);
+ }
+ mark_extent_buffer_accessed(eb, NULL);
+ return eb;
+ }
+ rcu_read_unlock();
+
+ return NULL;
+}
+
+#ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
+struct extent_buffer *alloc_test_extent_buffer(struct btrfs_fs_info *fs_info,
+ u64 start)
+{
+ struct extent_buffer *eb, *exists = NULL;
+ int ret;
+
+ eb = find_extent_buffer(fs_info, start);
+ if (eb)
+ return eb;
+ eb = alloc_dummy_extent_buffer(fs_info, start);
+ if (!eb)
+ return NULL;
+ eb->fs_info = fs_info;
+again:
+ ret = radix_tree_preload(GFP_NOFS);
+ if (ret)
+ goto free_eb;
+ spin_lock(&fs_info->buffer_lock);
+ ret = radix_tree_insert(&fs_info->buffer_radix,
+ start >> PAGE_SHIFT, eb);
+ spin_unlock(&fs_info->buffer_lock);
+ radix_tree_preload_end();
+ if (ret == -EEXIST) {
+ exists = find_extent_buffer(fs_info, start);
+ if (exists)
+ goto free_eb;
+ else
+ goto again;
+ }
+ check_buffer_tree_ref(eb);
+ set_bit(EXTENT_BUFFER_IN_TREE, &eb->bflags);
+
+ /*
+ * We will free dummy extent buffer's if they come into
+ * free_extent_buffer with a ref count of 2, but if we are using this we
+ * want the buffers to stay in memory until we're done with them, so
+ * bump the ref count again.
+ */
+ atomic_inc(&eb->refs);
+ return eb;
+free_eb:
+ btrfs_release_extent_buffer(eb);
+ return exists;
+}
+#endif
+
+struct extent_buffer *alloc_extent_buffer(struct btrfs_fs_info *fs_info,
+ u64 start)
+{
+ unsigned long len = fs_info->nodesize;
+ int num_pages;
+ int i;
+ unsigned long index = start >> PAGE_SHIFT;
+ struct extent_buffer *eb;
+ struct extent_buffer *exists = NULL;
+ struct page *p;
+ struct address_space *mapping = fs_info->btree_inode->i_mapping;
+ int uptodate = 1;
+ int ret;
+
+ if (!IS_ALIGNED(start, fs_info->sectorsize)) {
+ btrfs_err(fs_info, "bad tree block start %llu", start);
+ return ERR_PTR(-EINVAL);
+ }
+
+ eb = find_extent_buffer(fs_info, start);
+ if (eb)
+ return eb;
+
+ eb = __alloc_extent_buffer(fs_info, start, len);
+ if (!eb)
+ return ERR_PTR(-ENOMEM);
+
+ num_pages = num_extent_pages(eb);
+ for (i = 0; i < num_pages; i++, index++) {
+ p = find_or_create_page(mapping, index, GFP_NOFS|__GFP_NOFAIL);
+ if (!p) {
+ exists = ERR_PTR(-ENOMEM);
+ goto free_eb;
+ }
+
+ spin_lock(&mapping->private_lock);
+ if (PagePrivate(p)) {
+ /*
+ * We could have already allocated an eb for this page
+ * and attached one so lets see if we can get a ref on
+ * the existing eb, and if we can we know it's good and
+ * we can just return that one, else we know we can just
+ * overwrite page->private.
+ */
+ exists = (struct extent_buffer *)p->private;
+ if (atomic_inc_not_zero(&exists->refs)) {
+ spin_unlock(&mapping->private_lock);
+ unlock_page(p);
+ put_page(p);
+ mark_extent_buffer_accessed(exists, p);
+ goto free_eb;
+ }
+ exists = NULL;
+
+ /*
+ * Do this so attach doesn't complain and we need to
+ * drop the ref the old guy had.
+ */
+ ClearPagePrivate(p);
+ WARN_ON(PageDirty(p));
+ put_page(p);
+ }
+ attach_extent_buffer_page(eb, p);
+ spin_unlock(&mapping->private_lock);
+ WARN_ON(PageDirty(p));
+ eb->pages[i] = p;
+ if (!PageUptodate(p))
+ uptodate = 0;
+
+ /*
+ * We can't unlock the pages just yet since the extent buffer
+ * hasn't been properly inserted in the radix tree, this
+ * opens a race with btree_releasepage which can free a page
+ * while we are still filling in all pages for the buffer and
+ * we could crash.
+ */
+ }
+ if (uptodate)
+ set_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags);
+again:
+ ret = radix_tree_preload(GFP_NOFS);
+ if (ret) {
+ exists = ERR_PTR(ret);
+ goto free_eb;
+ }
+
+ spin_lock(&fs_info->buffer_lock);
+ ret = radix_tree_insert(&fs_info->buffer_radix,
+ start >> PAGE_SHIFT, eb);
+ spin_unlock(&fs_info->buffer_lock);
+ radix_tree_preload_end();
+ if (ret == -EEXIST) {
+ exists = find_extent_buffer(fs_info, start);
+ if (exists)
+ goto free_eb;
+ else
+ goto again;
+ }
+ /* add one reference for the tree */
+ check_buffer_tree_ref(eb);
+ set_bit(EXTENT_BUFFER_IN_TREE, &eb->bflags);
+
+ /*
+ * Now it's safe to unlock the pages because any calls to
+ * btree_releasepage will correctly detect that a page belongs to a
+ * live buffer and won't free them prematurely.
+ */
+ for (i = 0; i < num_pages; i++)
+ unlock_page(eb->pages[i]);
+ return eb;
+
+free_eb:
+ WARN_ON(!atomic_dec_and_test(&eb->refs));
+ for (i = 0; i < num_pages; i++) {
+ if (eb->pages[i])
+ unlock_page(eb->pages[i]);
+ }
+
+ btrfs_release_extent_buffer(eb);
+ return exists;
+}
+
+static inline void btrfs_release_extent_buffer_rcu(struct rcu_head *head)
+{
+ struct extent_buffer *eb =
+ container_of(head, struct extent_buffer, rcu_head);
+
+ __free_extent_buffer(eb);
+}
+
+static int release_extent_buffer(struct extent_buffer *eb)
+{
+ lockdep_assert_held(&eb->refs_lock);
+
+ WARN_ON(atomic_read(&eb->refs) == 0);
+ if (atomic_dec_and_test(&eb->refs)) {
+ if (test_and_clear_bit(EXTENT_BUFFER_IN_TREE, &eb->bflags)) {
+ struct btrfs_fs_info *fs_info = eb->fs_info;
+
+ spin_unlock(&eb->refs_lock);
+
+ spin_lock(&fs_info->buffer_lock);
+ radix_tree_delete(&fs_info->buffer_radix,
+ eb->start >> PAGE_SHIFT);
+ spin_unlock(&fs_info->buffer_lock);
+ } else {
+ spin_unlock(&eb->refs_lock);
+ }
+
+ /* Should be safe to release our pages at this point */
+ btrfs_release_extent_buffer_pages(eb);
+#ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
+ if (unlikely(test_bit(EXTENT_BUFFER_UNMAPPED, &eb->bflags))) {
+ __free_extent_buffer(eb);
+ return 1;
+ }
+#endif
+ call_rcu(&eb->rcu_head, btrfs_release_extent_buffer_rcu);
+ return 1;
+ }
+ spin_unlock(&eb->refs_lock);
+
+ return 0;
+}
+
+void free_extent_buffer(struct extent_buffer *eb)
+{
+ int refs;
+ int old;
+ if (!eb)
+ return;
+
+ while (1) {
+ refs = atomic_read(&eb->refs);
+ if (refs <= 3)
+ break;
+ old = atomic_cmpxchg(&eb->refs, refs, refs - 1);
+ if (old == refs)
+ return;
+ }
+
+ spin_lock(&eb->refs_lock);
+ if (atomic_read(&eb->refs) == 2 &&
+ test_bit(EXTENT_BUFFER_UNMAPPED, &eb->bflags))
+ atomic_dec(&eb->refs);
+
+ if (atomic_read(&eb->refs) == 2 &&
+ test_bit(EXTENT_BUFFER_STALE, &eb->bflags) &&
+ !extent_buffer_under_io(eb) &&
+ test_and_clear_bit(EXTENT_BUFFER_TREE_REF, &eb->bflags))
+ atomic_dec(&eb->refs);
+
+ /*
+ * I know this is terrible, but it's temporary until we stop tracking
+ * the uptodate bits and such for the extent buffers.
+ */
+ release_extent_buffer(eb);
+}
+
+void free_extent_buffer_stale(struct extent_buffer *eb)
+{
+ if (!eb)
+ return;
+
+ spin_lock(&eb->refs_lock);
+ set_bit(EXTENT_BUFFER_STALE, &eb->bflags);
+
+ if (atomic_read(&eb->refs) == 2 && !extent_buffer_under_io(eb) &&
+ test_and_clear_bit(EXTENT_BUFFER_TREE_REF, &eb->bflags))
+ atomic_dec(&eb->refs);
+ release_extent_buffer(eb);
+}
+
+void clear_extent_buffer_dirty(struct extent_buffer *eb)
+{
+ int i;
+ int num_pages;
+ struct page *page;
+
+ num_pages = num_extent_pages(eb);
+
+ for (i = 0; i < num_pages; i++) {
+ page = eb->pages[i];
+ if (!PageDirty(page))
+ continue;
+
+ lock_page(page);
+ WARN_ON(!PagePrivate(page));
+
+ clear_page_dirty_for_io(page);
+ xa_lock_irq(&page->mapping->i_pages);
+ if (!PageDirty(page)) {
+ radix_tree_tag_clear(&page->mapping->i_pages,
+ page_index(page),
+ PAGECACHE_TAG_DIRTY);
+ }
+ xa_unlock_irq(&page->mapping->i_pages);
+ ClearPageError(page);
+ unlock_page(page);
+ }
+ WARN_ON(atomic_read(&eb->refs) == 0);
+}
+
+int set_extent_buffer_dirty(struct extent_buffer *eb)
+{
+ int i;
+ int num_pages;
+ int was_dirty = 0;
+
+ check_buffer_tree_ref(eb);
+
+ was_dirty = test_and_set_bit(EXTENT_BUFFER_DIRTY, &eb->bflags);
+
+ num_pages = num_extent_pages(eb);
+ WARN_ON(atomic_read(&eb->refs) == 0);
+ WARN_ON(!test_bit(EXTENT_BUFFER_TREE_REF, &eb->bflags));
+
+ for (i = 0; i < num_pages; i++)
+ set_page_dirty(eb->pages[i]);
+ return was_dirty;
+}
+
+void clear_extent_buffer_uptodate(struct extent_buffer *eb)
+{
+ int i;
+ struct page *page;
+ int num_pages;
+
+ clear_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags);
+ num_pages = num_extent_pages(eb);
+ for (i = 0; i < num_pages; i++) {
+ page = eb->pages[i];
+ if (page)
+ ClearPageUptodate(page);
+ }
+}
+
+void set_extent_buffer_uptodate(struct extent_buffer *eb)
+{
+ int i;
+ struct page *page;
+ int num_pages;
+
+ set_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags);
+ num_pages = num_extent_pages(eb);
+ for (i = 0; i < num_pages; i++) {
+ page = eb->pages[i];
+ SetPageUptodate(page);
+ }
+}
+
+int read_extent_buffer_pages(struct extent_io_tree *tree,
+ struct extent_buffer *eb, int wait, int mirror_num)
+{
+ int i;
+ struct page *page;
+ int err;
+ int ret = 0;
+ int locked_pages = 0;
+ int all_uptodate = 1;
+ int num_pages;
+ unsigned long num_reads = 0;
+ struct bio *bio = NULL;
+ unsigned long bio_flags = 0;
+
+ if (test_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags))
+ return 0;
+
+ num_pages = num_extent_pages(eb);
+ for (i = 0; i < num_pages; i++) {
+ page = eb->pages[i];
+ if (wait == WAIT_NONE) {
+ if (!trylock_page(page))
+ goto unlock_exit;
+ } else {
+ lock_page(page);
+ }
+ locked_pages++;
+ }
+ /*
+ * We need to firstly lock all pages to make sure that
+ * the uptodate bit of our pages won't be affected by
+ * clear_extent_buffer_uptodate().
+ */
+ for (i = 0; i < num_pages; i++) {
+ page = eb->pages[i];
+ if (!PageUptodate(page)) {
+ num_reads++;
+ all_uptodate = 0;
+ }
+ }
+
+ if (all_uptodate) {
+ set_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags);
+ goto unlock_exit;
+ }
+
+ clear_bit(EXTENT_BUFFER_READ_ERR, &eb->bflags);
+ eb->read_mirror = 0;
+ atomic_set(&eb->io_pages, num_reads);
+ for (i = 0; i < num_pages; i++) {
+ page = eb->pages[i];
+
+ if (!PageUptodate(page)) {
+ if (ret) {
+ atomic_dec(&eb->io_pages);
+ unlock_page(page);
+ continue;
+ }
+
+ ClearPageError(page);
+ err = __extent_read_full_page(tree, page,
+ btree_get_extent, &bio,
+ mirror_num, &bio_flags,
+ REQ_META);
+ if (err) {
+ ret = err;
+ /*
+ * We use &bio in above __extent_read_full_page,
+ * so we ensure that if it returns error, the
+ * current page fails to add itself to bio and
+ * it's been unlocked.
+ *
+ * We must dec io_pages by ourselves.
+ */
+ atomic_dec(&eb->io_pages);
+ }
+ } else {
+ unlock_page(page);
+ }
+ }
+
+ if (bio) {
+ err = submit_one_bio(bio, mirror_num, bio_flags);
+ if (err)
+ return err;
+ }
+
+ if (ret || wait != WAIT_COMPLETE)
+ return ret;
+
+ for (i = 0; i < num_pages; i++) {
+ page = eb->pages[i];
+ wait_on_page_locked(page);
+ if (!PageUptodate(page))
+ ret = -EIO;
+ }
+
+ return ret;
+
+unlock_exit:
+ while (locked_pages > 0) {
+ locked_pages--;
+ page = eb->pages[locked_pages];
+ unlock_page(page);
+ }
+ return ret;
+}
+
+void read_extent_buffer(const struct extent_buffer *eb, void *dstv,
+ unsigned long start, unsigned long len)
+{
+ size_t cur;
+ size_t offset;
+ struct page *page;
+ char *kaddr;
+ char *dst = (char *)dstv;
+ size_t start_offset = eb->start & ((u64)PAGE_SIZE - 1);
+ unsigned long i = (start_offset + start) >> PAGE_SHIFT;
+
+ if (start + len > eb->len) {
+ WARN(1, KERN_ERR "btrfs bad mapping eb start %llu len %lu, wanted %lu %lu\n",
+ eb->start, eb->len, start, len);
+ memset(dst, 0, len);
+ return;
+ }
+
+ offset = (start_offset + start) & (PAGE_SIZE - 1);
+
+ while (len > 0) {
+ page = eb->pages[i];
+
+ cur = min(len, (PAGE_SIZE - offset));
+ kaddr = page_address(page);
+ memcpy(dst, kaddr + offset, cur);
+
+ dst += cur;
+ len -= cur;
+ offset = 0;
+ i++;
+ }
+}
+
+int read_extent_buffer_to_user(const struct extent_buffer *eb,
+ void __user *dstv,
+ unsigned long start, unsigned long len)
+{
+ size_t cur;
+ size_t offset;
+ struct page *page;
+ char *kaddr;
+ char __user *dst = (char __user *)dstv;
+ size_t start_offset = eb->start & ((u64)PAGE_SIZE - 1);
+ unsigned long i = (start_offset + start) >> PAGE_SHIFT;
+ int ret = 0;
+
+ WARN_ON(start > eb->len);
+ WARN_ON(start + len > eb->start + eb->len);
+
+ offset = (start_offset + start) & (PAGE_SIZE - 1);
+
+ while (len > 0) {
+ page = eb->pages[i];
+
+ cur = min(len, (PAGE_SIZE - offset));
+ kaddr = page_address(page);
+ if (copy_to_user(dst, kaddr + offset, cur)) {
+ ret = -EFAULT;
+ break;
+ }
+
+ dst += cur;
+ len -= cur;
+ offset = 0;
+ i++;
+ }
+
+ return ret;
+}
+
+/*
+ * return 0 if the item is found within a page.
+ * return 1 if the item spans two pages.
+ * return -EINVAL otherwise.
+ */
+int map_private_extent_buffer(const struct extent_buffer *eb,
+ unsigned long start, unsigned long min_len,
+ char **map, unsigned long *map_start,
+ unsigned long *map_len)
+{
+ size_t offset = start & (PAGE_SIZE - 1);
+ char *kaddr;
+ struct page *p;
+ size_t start_offset = eb->start & ((u64)PAGE_SIZE - 1);
+ unsigned long i = (start_offset + start) >> PAGE_SHIFT;
+ unsigned long end_i = (start_offset + start + min_len - 1) >>
+ PAGE_SHIFT;
+
+ if (start + min_len > eb->len) {
+ WARN(1, KERN_ERR "btrfs bad mapping eb start %llu len %lu, wanted %lu %lu\n",
+ eb->start, eb->len, start, min_len);
+ return -EINVAL;
+ }
+
+ if (i != end_i)
+ return 1;
+
+ if (i == 0) {
+ offset = start_offset;
+ *map_start = 0;
+ } else {
+ offset = 0;
+ *map_start = ((u64)i << PAGE_SHIFT) - start_offset;
+ }
+
+ p = eb->pages[i];
+ kaddr = page_address(p);
+ *map = kaddr + offset;
+ *map_len = PAGE_SIZE - offset;
+ return 0;
+}
+
+int memcmp_extent_buffer(const struct extent_buffer *eb, const void *ptrv,
+ unsigned long start, unsigned long len)
+{
+ size_t cur;
+ size_t offset;
+ struct page *page;
+ char *kaddr;
+ char *ptr = (char *)ptrv;
+ size_t start_offset = eb->start & ((u64)PAGE_SIZE - 1);
+ unsigned long i = (start_offset + start) >> PAGE_SHIFT;
+ int ret = 0;
+
+ WARN_ON(start > eb->len);
+ WARN_ON(start + len > eb->start + eb->len);
+
+ offset = (start_offset + start) & (PAGE_SIZE - 1);
+
+ while (len > 0) {
+ page = eb->pages[i];
+
+ cur = min(len, (PAGE_SIZE - offset));
+
+ kaddr = page_address(page);
+ ret = memcmp(ptr, kaddr + offset, cur);
+ if (ret)
+ break;
+
+ ptr += cur;
+ len -= cur;
+ offset = 0;
+ i++;
+ }
+ return ret;
+}
+
+void write_extent_buffer_chunk_tree_uuid(struct extent_buffer *eb,
+ const void *srcv)
+{
+ char *kaddr;
+
+ WARN_ON(!PageUptodate(eb->pages[0]));
+ kaddr = page_address(eb->pages[0]);
+ memcpy(kaddr + offsetof(struct btrfs_header, chunk_tree_uuid), srcv,
+ BTRFS_FSID_SIZE);
+}
+
+void write_extent_buffer_fsid(struct extent_buffer *eb, const void *srcv)
+{
+ char *kaddr;
+
+ WARN_ON(!PageUptodate(eb->pages[0]));
+ kaddr = page_address(eb->pages[0]);
+ memcpy(kaddr + offsetof(struct btrfs_header, fsid), srcv,
+ BTRFS_FSID_SIZE);
+}
+
+void write_extent_buffer(struct extent_buffer *eb, const void *srcv,
+ unsigned long start, unsigned long len)
+{
+ size_t cur;
+ size_t offset;
+ struct page *page;
+ char *kaddr;
+ char *src = (char *)srcv;
+ size_t start_offset = eb->start & ((u64)PAGE_SIZE - 1);
+ unsigned long i = (start_offset + start) >> PAGE_SHIFT;
+
+ WARN_ON(start > eb->len);
+ WARN_ON(start + len > eb->start + eb->len);
+
+ offset = (start_offset + start) & (PAGE_SIZE - 1);
+
+ while (len > 0) {
+ page = eb->pages[i];
+ WARN_ON(!PageUptodate(page));
+
+ cur = min(len, PAGE_SIZE - offset);
+ kaddr = page_address(page);
+ memcpy(kaddr + offset, src, cur);
+
+ src += cur;
+ len -= cur;
+ offset = 0;
+ i++;
+ }
+}
+
+void memzero_extent_buffer(struct extent_buffer *eb, unsigned long start,
+ unsigned long len)
+{
+ size_t cur;
+ size_t offset;
+ struct page *page;
+ char *kaddr;
+ size_t start_offset = eb->start & ((u64)PAGE_SIZE - 1);
+ unsigned long i = (start_offset + start) >> PAGE_SHIFT;
+
+ WARN_ON(start > eb->len);
+ WARN_ON(start + len > eb->start + eb->len);
+
+ offset = (start_offset + start) & (PAGE_SIZE - 1);
+
+ while (len > 0) {
+ page = eb->pages[i];
+ WARN_ON(!PageUptodate(page));
+
+ cur = min(len, PAGE_SIZE - offset);
+ kaddr = page_address(page);
+ memset(kaddr + offset, 0, cur);
+
+ len -= cur;
+ offset = 0;
+ i++;
+ }
+}
+
+void copy_extent_buffer_full(struct extent_buffer *dst,
+ struct extent_buffer *src)
+{
+ int i;
+ int num_pages;
+
+ ASSERT(dst->len == src->len);
+
+ num_pages = num_extent_pages(dst);
+ for (i = 0; i < num_pages; i++)
+ copy_page(page_address(dst->pages[i]),
+ page_address(src->pages[i]));
+}
+
+void copy_extent_buffer(struct extent_buffer *dst, struct extent_buffer *src,
+ unsigned long dst_offset, unsigned long src_offset,
+ unsigned long len)
+{
+ u64 dst_len = dst->len;
+ size_t cur;
+ size_t offset;
+ struct page *page;
+ char *kaddr;
+ size_t start_offset = dst->start & ((u64)PAGE_SIZE - 1);
+ unsigned long i = (start_offset + dst_offset) >> PAGE_SHIFT;
+
+ WARN_ON(src->len != dst_len);
+
+ offset = (start_offset + dst_offset) &
+ (PAGE_SIZE - 1);
+
+ while (len > 0) {
+ page = dst->pages[i];
+ WARN_ON(!PageUptodate(page));
+
+ cur = min(len, (unsigned long)(PAGE_SIZE - offset));
+
+ kaddr = page_address(page);
+ read_extent_buffer(src, kaddr + offset, src_offset, cur);
+
+ src_offset += cur;
+ len -= cur;
+ offset = 0;
+ i++;
+ }
+}
+
+/*
+ * eb_bitmap_offset() - calculate the page and offset of the byte containing the
+ * given bit number
+ * @eb: the extent buffer
+ * @start: offset of the bitmap item in the extent buffer
+ * @nr: bit number
+ * @page_index: return index of the page in the extent buffer that contains the
+ * given bit number
+ * @page_offset: return offset into the page given by page_index
+ *
+ * This helper hides the ugliness of finding the byte in an extent buffer which
+ * contains a given bit.
+ */
+static inline void eb_bitmap_offset(struct extent_buffer *eb,
+ unsigned long start, unsigned long nr,
+ unsigned long *page_index,
+ size_t *page_offset)
+{
+ size_t start_offset = eb->start & ((u64)PAGE_SIZE - 1);
+ size_t byte_offset = BIT_BYTE(nr);
+ size_t offset;
+
+ /*
+ * The byte we want is the offset of the extent buffer + the offset of
+ * the bitmap item in the extent buffer + the offset of the byte in the
+ * bitmap item.
+ */
+ offset = start_offset + start + byte_offset;
+
+ *page_index = offset >> PAGE_SHIFT;
+ *page_offset = offset & (PAGE_SIZE - 1);
+}
+
+/**
+ * extent_buffer_test_bit - determine whether a bit in a bitmap item is set
+ * @eb: the extent buffer
+ * @start: offset of the bitmap item in the extent buffer
+ * @nr: bit number to test
+ */
+int extent_buffer_test_bit(struct extent_buffer *eb, unsigned long start,
+ unsigned long nr)
+{
+ u8 *kaddr;
+ struct page *page;
+ unsigned long i;
+ size_t offset;
+
+ eb_bitmap_offset(eb, start, nr, &i, &offset);
+ page = eb->pages[i];
+ WARN_ON(!PageUptodate(page));
+ kaddr = page_address(page);
+ return 1U & (kaddr[offset] >> (nr & (BITS_PER_BYTE - 1)));
+}
+
+/**
+ * extent_buffer_bitmap_set - set an area of a bitmap
+ * @eb: the extent buffer
+ * @start: offset of the bitmap item in the extent buffer
+ * @pos: bit number of the first bit
+ * @len: number of bits to set
+ */
+void extent_buffer_bitmap_set(struct extent_buffer *eb, unsigned long start,
+ unsigned long pos, unsigned long len)
+{
+ u8 *kaddr;
+ struct page *page;
+ unsigned long i;
+ size_t offset;
+ const unsigned int size = pos + len;
+ int bits_to_set = BITS_PER_BYTE - (pos % BITS_PER_BYTE);
+ u8 mask_to_set = BITMAP_FIRST_BYTE_MASK(pos);
+
+ eb_bitmap_offset(eb, start, pos, &i, &offset);
+ page = eb->pages[i];
+ WARN_ON(!PageUptodate(page));
+ kaddr = page_address(page);
+
+ while (len >= bits_to_set) {
+ kaddr[offset] |= mask_to_set;
+ len -= bits_to_set;
+ bits_to_set = BITS_PER_BYTE;
+ mask_to_set = ~0;
+ if (++offset >= PAGE_SIZE && len > 0) {
+ offset = 0;
+ page = eb->pages[++i];
+ WARN_ON(!PageUptodate(page));
+ kaddr = page_address(page);
+ }
+ }
+ if (len) {
+ mask_to_set &= BITMAP_LAST_BYTE_MASK(size);
+ kaddr[offset] |= mask_to_set;
+ }
+}
+
+
+/**
+ * extent_buffer_bitmap_clear - clear an area of a bitmap
+ * @eb: the extent buffer
+ * @start: offset of the bitmap item in the extent buffer
+ * @pos: bit number of the first bit
+ * @len: number of bits to clear
+ */
+void extent_buffer_bitmap_clear(struct extent_buffer *eb, unsigned long start,
+ unsigned long pos, unsigned long len)
+{
+ u8 *kaddr;
+ struct page *page;
+ unsigned long i;
+ size_t offset;
+ const unsigned int size = pos + len;
+ int bits_to_clear = BITS_PER_BYTE - (pos % BITS_PER_BYTE);
+ u8 mask_to_clear = BITMAP_FIRST_BYTE_MASK(pos);
+
+ eb_bitmap_offset(eb, start, pos, &i, &offset);
+ page = eb->pages[i];
+ WARN_ON(!PageUptodate(page));
+ kaddr = page_address(page);
+
+ while (len >= bits_to_clear) {
+ kaddr[offset] &= ~mask_to_clear;
+ len -= bits_to_clear;
+ bits_to_clear = BITS_PER_BYTE;
+ mask_to_clear = ~0;
+ if (++offset >= PAGE_SIZE && len > 0) {
+ offset = 0;
+ page = eb->pages[++i];
+ WARN_ON(!PageUptodate(page));
+ kaddr = page_address(page);
+ }
+ }
+ if (len) {
+ mask_to_clear &= BITMAP_LAST_BYTE_MASK(size);
+ kaddr[offset] &= ~mask_to_clear;
+ }
+}
+
+static inline bool areas_overlap(unsigned long src, unsigned long dst, unsigned long len)
+{
+ unsigned long distance = (src > dst) ? src - dst : dst - src;
+ return distance < len;
+}
+
+static void copy_pages(struct page *dst_page, struct page *src_page,
+ unsigned long dst_off, unsigned long src_off,
+ unsigned long len)
+{
+ char *dst_kaddr = page_address(dst_page);
+ char *src_kaddr;
+ int must_memmove = 0;
+
+ if (dst_page != src_page) {
+ src_kaddr = page_address(src_page);
+ } else {
+ src_kaddr = dst_kaddr;
+ if (areas_overlap(src_off, dst_off, len))
+ must_memmove = 1;
+ }
+
+ if (must_memmove)
+ memmove(dst_kaddr + dst_off, src_kaddr + src_off, len);
+ else
+ memcpy(dst_kaddr + dst_off, src_kaddr + src_off, len);
+}
+
+void memcpy_extent_buffer(struct extent_buffer *dst, unsigned long dst_offset,
+ unsigned long src_offset, unsigned long len)
+{
+ struct btrfs_fs_info *fs_info = dst->fs_info;
+ size_t cur;
+ size_t dst_off_in_page;
+ size_t src_off_in_page;
+ size_t start_offset = dst->start & ((u64)PAGE_SIZE - 1);
+ unsigned long dst_i;
+ unsigned long src_i;
+
+ if (src_offset + len > dst->len) {
+ btrfs_err(fs_info,
+ "memmove bogus src_offset %lu move len %lu dst len %lu",
+ src_offset, len, dst->len);
+ BUG_ON(1);
+ }
+ if (dst_offset + len > dst->len) {
+ btrfs_err(fs_info,
+ "memmove bogus dst_offset %lu move len %lu dst len %lu",
+ dst_offset, len, dst->len);
+ BUG_ON(1);
+ }
+
+ while (len > 0) {
+ dst_off_in_page = (start_offset + dst_offset) &
+ (PAGE_SIZE - 1);
+ src_off_in_page = (start_offset + src_offset) &
+ (PAGE_SIZE - 1);
+
+ dst_i = (start_offset + dst_offset) >> PAGE_SHIFT;
+ src_i = (start_offset + src_offset) >> PAGE_SHIFT;
+
+ cur = min(len, (unsigned long)(PAGE_SIZE -
+ src_off_in_page));
+ cur = min_t(unsigned long, cur,
+ (unsigned long)(PAGE_SIZE - dst_off_in_page));
+
+ copy_pages(dst->pages[dst_i], dst->pages[src_i],
+ dst_off_in_page, src_off_in_page, cur);
+
+ src_offset += cur;
+ dst_offset += cur;
+ len -= cur;
+ }
+}
+
+void memmove_extent_buffer(struct extent_buffer *dst, unsigned long dst_offset,
+ unsigned long src_offset, unsigned long len)
+{
+ struct btrfs_fs_info *fs_info = dst->fs_info;
+ size_t cur;
+ size_t dst_off_in_page;
+ size_t src_off_in_page;
+ unsigned long dst_end = dst_offset + len - 1;
+ unsigned long src_end = src_offset + len - 1;
+ size_t start_offset = dst->start & ((u64)PAGE_SIZE - 1);
+ unsigned long dst_i;
+ unsigned long src_i;
+
+ if (src_offset + len > dst->len) {
+ btrfs_err(fs_info,
+ "memmove bogus src_offset %lu move len %lu len %lu",
+ src_offset, len, dst->len);
+ BUG_ON(1);
+ }
+ if (dst_offset + len > dst->len) {
+ btrfs_err(fs_info,
+ "memmove bogus dst_offset %lu move len %lu len %lu",
+ dst_offset, len, dst->len);
+ BUG_ON(1);
+ }
+ if (dst_offset < src_offset) {
+ memcpy_extent_buffer(dst, dst_offset, src_offset, len);
+ return;
+ }
+ while (len > 0) {
+ dst_i = (start_offset + dst_end) >> PAGE_SHIFT;
+ src_i = (start_offset + src_end) >> PAGE_SHIFT;
+
+ dst_off_in_page = (start_offset + dst_end) &
+ (PAGE_SIZE - 1);
+ src_off_in_page = (start_offset + src_end) &
+ (PAGE_SIZE - 1);
+
+ cur = min_t(unsigned long, len, src_off_in_page + 1);
+ cur = min(cur, dst_off_in_page + 1);
+ copy_pages(dst->pages[dst_i], dst->pages[src_i],
+ dst_off_in_page - cur + 1,
+ src_off_in_page - cur + 1, cur);
+
+ dst_end -= cur;
+ src_end -= cur;
+ len -= cur;
+ }
+}
+
+int try_release_extent_buffer(struct page *page)
+{
+ struct extent_buffer *eb;
+
+ /*
+ * We need to make sure nobody is attaching this page to an eb right
+ * now.
+ */
+ spin_lock(&page->mapping->private_lock);
+ if (!PagePrivate(page)) {
+ spin_unlock(&page->mapping->private_lock);
+ return 1;
+ }
+
+ eb = (struct extent_buffer *)page->private;
+ BUG_ON(!eb);
+
+ /*
+ * This is a little awful but should be ok, we need to make sure that
+ * the eb doesn't disappear out from under us while we're looking at
+ * this page.
+ */
+ spin_lock(&eb->refs_lock);
+ if (atomic_read(&eb->refs) != 1 || extent_buffer_under_io(eb)) {
+ spin_unlock(&eb->refs_lock);
+ spin_unlock(&page->mapping->private_lock);
+ return 0;
+ }
+ spin_unlock(&page->mapping->private_lock);
+
+ /*
+ * If tree ref isn't set then we know the ref on this eb is a real ref,
+ * so just return, this page will likely be freed soon anyway.
+ */
+ if (!test_and_clear_bit(EXTENT_BUFFER_TREE_REF, &eb->bflags)) {
+ spin_unlock(&eb->refs_lock);
+ return 0;
+ }
+
+ return release_extent_buffer(eb);
+}