v4.19.13 snapshot.
diff --git a/fs/btrfs/inode-map.c b/fs/btrfs/inode-map.c
new file mode 100644
index 0000000..ffca2ab
--- /dev/null
+++ b/fs/btrfs/inode-map.c
@@ -0,0 +1,561 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2007 Oracle. All rights reserved.
+ */
+
+#include <linux/kthread.h>
+#include <linux/pagemap.h>
+
+#include "ctree.h"
+#include "disk-io.h"
+#include "free-space-cache.h"
+#include "inode-map.h"
+#include "transaction.h"
+
+static int caching_kthread(void *data)
+{
+ struct btrfs_root *root = data;
+ struct btrfs_fs_info *fs_info = root->fs_info;
+ struct btrfs_free_space_ctl *ctl = root->free_ino_ctl;
+ struct btrfs_key key;
+ struct btrfs_path *path;
+ struct extent_buffer *leaf;
+ u64 last = (u64)-1;
+ int slot;
+ int ret;
+
+ if (!btrfs_test_opt(fs_info, INODE_MAP_CACHE))
+ return 0;
+
+ path = btrfs_alloc_path();
+ if (!path)
+ return -ENOMEM;
+
+ /* Since the commit root is read-only, we can safely skip locking. */
+ path->skip_locking = 1;
+ path->search_commit_root = 1;
+ path->reada = READA_FORWARD;
+
+ key.objectid = BTRFS_FIRST_FREE_OBJECTID;
+ key.offset = 0;
+ key.type = BTRFS_INODE_ITEM_KEY;
+again:
+ /* need to make sure the commit_root doesn't disappear */
+ down_read(&fs_info->commit_root_sem);
+
+ ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
+ if (ret < 0)
+ goto out;
+
+ while (1) {
+ if (btrfs_fs_closing(fs_info))
+ goto out;
+
+ leaf = path->nodes[0];
+ slot = path->slots[0];
+ if (slot >= btrfs_header_nritems(leaf)) {
+ ret = btrfs_next_leaf(root, path);
+ if (ret < 0)
+ goto out;
+ else if (ret > 0)
+ break;
+
+ if (need_resched() ||
+ btrfs_transaction_in_commit(fs_info)) {
+ leaf = path->nodes[0];
+
+ if (WARN_ON(btrfs_header_nritems(leaf) == 0))
+ break;
+
+ /*
+ * Save the key so we can advances forward
+ * in the next search.
+ */
+ btrfs_item_key_to_cpu(leaf, &key, 0);
+ btrfs_release_path(path);
+ root->ino_cache_progress = last;
+ up_read(&fs_info->commit_root_sem);
+ schedule_timeout(1);
+ goto again;
+ } else
+ continue;
+ }
+
+ btrfs_item_key_to_cpu(leaf, &key, slot);
+
+ if (key.type != BTRFS_INODE_ITEM_KEY)
+ goto next;
+
+ if (key.objectid >= root->highest_objectid)
+ break;
+
+ if (last != (u64)-1 && last + 1 != key.objectid) {
+ __btrfs_add_free_space(fs_info, ctl, last + 1,
+ key.objectid - last - 1);
+ wake_up(&root->ino_cache_wait);
+ }
+
+ last = key.objectid;
+next:
+ path->slots[0]++;
+ }
+
+ if (last < root->highest_objectid - 1) {
+ __btrfs_add_free_space(fs_info, ctl, last + 1,
+ root->highest_objectid - last - 1);
+ }
+
+ spin_lock(&root->ino_cache_lock);
+ root->ino_cache_state = BTRFS_CACHE_FINISHED;
+ spin_unlock(&root->ino_cache_lock);
+
+ root->ino_cache_progress = (u64)-1;
+ btrfs_unpin_free_ino(root);
+out:
+ wake_up(&root->ino_cache_wait);
+ up_read(&fs_info->commit_root_sem);
+
+ btrfs_free_path(path);
+
+ return ret;
+}
+
+static void start_caching(struct btrfs_root *root)
+{
+ struct btrfs_fs_info *fs_info = root->fs_info;
+ struct btrfs_free_space_ctl *ctl = root->free_ino_ctl;
+ struct task_struct *tsk;
+ int ret;
+ u64 objectid;
+
+ if (!btrfs_test_opt(fs_info, INODE_MAP_CACHE))
+ return;
+
+ spin_lock(&root->ino_cache_lock);
+ if (root->ino_cache_state != BTRFS_CACHE_NO) {
+ spin_unlock(&root->ino_cache_lock);
+ return;
+ }
+
+ root->ino_cache_state = BTRFS_CACHE_STARTED;
+ spin_unlock(&root->ino_cache_lock);
+
+ ret = load_free_ino_cache(fs_info, root);
+ if (ret == 1) {
+ spin_lock(&root->ino_cache_lock);
+ root->ino_cache_state = BTRFS_CACHE_FINISHED;
+ spin_unlock(&root->ino_cache_lock);
+ return;
+ }
+
+ /*
+ * It can be quite time-consuming to fill the cache by searching
+ * through the extent tree, and this can keep ino allocation path
+ * waiting. Therefore at start we quickly find out the highest
+ * inode number and we know we can use inode numbers which fall in
+ * [highest_ino + 1, BTRFS_LAST_FREE_OBJECTID].
+ */
+ ret = btrfs_find_free_objectid(root, &objectid);
+ if (!ret && objectid <= BTRFS_LAST_FREE_OBJECTID) {
+ __btrfs_add_free_space(fs_info, ctl, objectid,
+ BTRFS_LAST_FREE_OBJECTID - objectid + 1);
+ }
+
+ tsk = kthread_run(caching_kthread, root, "btrfs-ino-cache-%llu",
+ root->root_key.objectid);
+ if (IS_ERR(tsk)) {
+ btrfs_warn(fs_info, "failed to start inode caching task");
+ btrfs_clear_pending_and_info(fs_info, INODE_MAP_CACHE,
+ "disabling inode map caching");
+ }
+}
+
+int btrfs_find_free_ino(struct btrfs_root *root, u64 *objectid)
+{
+ if (!btrfs_test_opt(root->fs_info, INODE_MAP_CACHE))
+ return btrfs_find_free_objectid(root, objectid);
+
+again:
+ *objectid = btrfs_find_ino_for_alloc(root);
+
+ if (*objectid != 0)
+ return 0;
+
+ start_caching(root);
+
+ wait_event(root->ino_cache_wait,
+ root->ino_cache_state == BTRFS_CACHE_FINISHED ||
+ root->free_ino_ctl->free_space > 0);
+
+ if (root->ino_cache_state == BTRFS_CACHE_FINISHED &&
+ root->free_ino_ctl->free_space == 0)
+ return -ENOSPC;
+ else
+ goto again;
+}
+
+void btrfs_return_ino(struct btrfs_root *root, u64 objectid)
+{
+ struct btrfs_fs_info *fs_info = root->fs_info;
+ struct btrfs_free_space_ctl *pinned = root->free_ino_pinned;
+
+ if (!btrfs_test_opt(fs_info, INODE_MAP_CACHE))
+ return;
+again:
+ if (root->ino_cache_state == BTRFS_CACHE_FINISHED) {
+ __btrfs_add_free_space(fs_info, pinned, objectid, 1);
+ } else {
+ down_write(&fs_info->commit_root_sem);
+ spin_lock(&root->ino_cache_lock);
+ if (root->ino_cache_state == BTRFS_CACHE_FINISHED) {
+ spin_unlock(&root->ino_cache_lock);
+ up_write(&fs_info->commit_root_sem);
+ goto again;
+ }
+ spin_unlock(&root->ino_cache_lock);
+
+ start_caching(root);
+
+ __btrfs_add_free_space(fs_info, pinned, objectid, 1);
+
+ up_write(&fs_info->commit_root_sem);
+ }
+}
+
+/*
+ * When a transaction is committed, we'll move those inode numbers which are
+ * smaller than root->ino_cache_progress from pinned tree to free_ino tree, and
+ * others will just be dropped, because the commit root we were searching has
+ * changed.
+ *
+ * Must be called with root->fs_info->commit_root_sem held
+ */
+void btrfs_unpin_free_ino(struct btrfs_root *root)
+{
+ struct btrfs_free_space_ctl *ctl = root->free_ino_ctl;
+ struct rb_root *rbroot = &root->free_ino_pinned->free_space_offset;
+ spinlock_t *rbroot_lock = &root->free_ino_pinned->tree_lock;
+ struct btrfs_free_space *info;
+ struct rb_node *n;
+ u64 count;
+
+ if (!btrfs_test_opt(root->fs_info, INODE_MAP_CACHE))
+ return;
+
+ while (1) {
+ spin_lock(rbroot_lock);
+ n = rb_first(rbroot);
+ if (!n) {
+ spin_unlock(rbroot_lock);
+ break;
+ }
+
+ info = rb_entry(n, struct btrfs_free_space, offset_index);
+ BUG_ON(info->bitmap); /* Logic error */
+
+ if (info->offset > root->ino_cache_progress)
+ count = 0;
+ else
+ count = min(root->ino_cache_progress - info->offset + 1,
+ info->bytes);
+
+ rb_erase(&info->offset_index, rbroot);
+ spin_unlock(rbroot_lock);
+ if (count)
+ __btrfs_add_free_space(root->fs_info, ctl,
+ info->offset, count);
+ kmem_cache_free(btrfs_free_space_cachep, info);
+ }
+}
+
+#define INIT_THRESHOLD ((SZ_32K / 2) / sizeof(struct btrfs_free_space))
+#define INODES_PER_BITMAP (PAGE_SIZE * 8)
+
+/*
+ * The goal is to keep the memory used by the free_ino tree won't
+ * exceed the memory if we use bitmaps only.
+ */
+static void recalculate_thresholds(struct btrfs_free_space_ctl *ctl)
+{
+ struct btrfs_free_space *info;
+ struct rb_node *n;
+ int max_ino;
+ int max_bitmaps;
+
+ n = rb_last(&ctl->free_space_offset);
+ if (!n) {
+ ctl->extents_thresh = INIT_THRESHOLD;
+ return;
+ }
+ info = rb_entry(n, struct btrfs_free_space, offset_index);
+
+ /*
+ * Find the maximum inode number in the filesystem. Note we
+ * ignore the fact that this can be a bitmap, because we are
+ * not doing precise calculation.
+ */
+ max_ino = info->bytes - 1;
+
+ max_bitmaps = ALIGN(max_ino, INODES_PER_BITMAP) / INODES_PER_BITMAP;
+ if (max_bitmaps <= ctl->total_bitmaps) {
+ ctl->extents_thresh = 0;
+ return;
+ }
+
+ ctl->extents_thresh = (max_bitmaps - ctl->total_bitmaps) *
+ PAGE_SIZE / sizeof(*info);
+}
+
+/*
+ * We don't fall back to bitmap, if we are below the extents threshold
+ * or this chunk of inode numbers is a big one.
+ */
+static bool use_bitmap(struct btrfs_free_space_ctl *ctl,
+ struct btrfs_free_space *info)
+{
+ if (ctl->free_extents < ctl->extents_thresh ||
+ info->bytes > INODES_PER_BITMAP / 10)
+ return false;
+
+ return true;
+}
+
+static const struct btrfs_free_space_op free_ino_op = {
+ .recalc_thresholds = recalculate_thresholds,
+ .use_bitmap = use_bitmap,
+};
+
+static void pinned_recalc_thresholds(struct btrfs_free_space_ctl *ctl)
+{
+}
+
+static bool pinned_use_bitmap(struct btrfs_free_space_ctl *ctl,
+ struct btrfs_free_space *info)
+{
+ /*
+ * We always use extents for two reasons:
+ *
+ * - The pinned tree is only used during the process of caching
+ * work.
+ * - Make code simpler. See btrfs_unpin_free_ino().
+ */
+ return false;
+}
+
+static const struct btrfs_free_space_op pinned_free_ino_op = {
+ .recalc_thresholds = pinned_recalc_thresholds,
+ .use_bitmap = pinned_use_bitmap,
+};
+
+void btrfs_init_free_ino_ctl(struct btrfs_root *root)
+{
+ struct btrfs_free_space_ctl *ctl = root->free_ino_ctl;
+ struct btrfs_free_space_ctl *pinned = root->free_ino_pinned;
+
+ spin_lock_init(&ctl->tree_lock);
+ ctl->unit = 1;
+ ctl->start = 0;
+ ctl->private = NULL;
+ ctl->op = &free_ino_op;
+ INIT_LIST_HEAD(&ctl->trimming_ranges);
+ mutex_init(&ctl->cache_writeout_mutex);
+
+ /*
+ * Initially we allow to use 16K of ram to cache chunks of
+ * inode numbers before we resort to bitmaps. This is somewhat
+ * arbitrary, but it will be adjusted in runtime.
+ */
+ ctl->extents_thresh = INIT_THRESHOLD;
+
+ spin_lock_init(&pinned->tree_lock);
+ pinned->unit = 1;
+ pinned->start = 0;
+ pinned->private = NULL;
+ pinned->extents_thresh = 0;
+ pinned->op = &pinned_free_ino_op;
+}
+
+int btrfs_save_ino_cache(struct btrfs_root *root,
+ struct btrfs_trans_handle *trans)
+{
+ struct btrfs_fs_info *fs_info = root->fs_info;
+ struct btrfs_free_space_ctl *ctl = root->free_ino_ctl;
+ struct btrfs_path *path;
+ struct inode *inode;
+ struct btrfs_block_rsv *rsv;
+ struct extent_changeset *data_reserved = NULL;
+ u64 num_bytes;
+ u64 alloc_hint = 0;
+ int ret;
+ int prealloc;
+ bool retry = false;
+
+ /* only fs tree and subvol/snap needs ino cache */
+ if (root->root_key.objectid != BTRFS_FS_TREE_OBJECTID &&
+ (root->root_key.objectid < BTRFS_FIRST_FREE_OBJECTID ||
+ root->root_key.objectid > BTRFS_LAST_FREE_OBJECTID))
+ return 0;
+
+ /* Don't save inode cache if we are deleting this root */
+ if (btrfs_root_refs(&root->root_item) == 0)
+ return 0;
+
+ if (!btrfs_test_opt(fs_info, INODE_MAP_CACHE))
+ return 0;
+
+ path = btrfs_alloc_path();
+ if (!path)
+ return -ENOMEM;
+
+ rsv = trans->block_rsv;
+ trans->block_rsv = &fs_info->trans_block_rsv;
+
+ num_bytes = trans->bytes_reserved;
+ /*
+ * 1 item for inode item insertion if need
+ * 4 items for inode item update (in the worst case)
+ * 1 items for slack space if we need do truncation
+ * 1 item for free space object
+ * 3 items for pre-allocation
+ */
+ trans->bytes_reserved = btrfs_calc_trans_metadata_size(fs_info, 10);
+ ret = btrfs_block_rsv_add(root, trans->block_rsv,
+ trans->bytes_reserved,
+ BTRFS_RESERVE_NO_FLUSH);
+ if (ret)
+ goto out;
+ trace_btrfs_space_reservation(fs_info, "ino_cache", trans->transid,
+ trans->bytes_reserved, 1);
+again:
+ inode = lookup_free_ino_inode(root, path);
+ if (IS_ERR(inode) && (PTR_ERR(inode) != -ENOENT || retry)) {
+ ret = PTR_ERR(inode);
+ goto out_release;
+ }
+
+ if (IS_ERR(inode)) {
+ BUG_ON(retry); /* Logic error */
+ retry = true;
+
+ ret = create_free_ino_inode(root, trans, path);
+ if (ret)
+ goto out_release;
+ goto again;
+ }
+
+ BTRFS_I(inode)->generation = 0;
+ ret = btrfs_update_inode(trans, root, inode);
+ if (ret) {
+ btrfs_abort_transaction(trans, ret);
+ goto out_put;
+ }
+
+ if (i_size_read(inode) > 0) {
+ ret = btrfs_truncate_free_space_cache(trans, NULL, inode);
+ if (ret) {
+ if (ret != -ENOSPC)
+ btrfs_abort_transaction(trans, ret);
+ goto out_put;
+ }
+ }
+
+ spin_lock(&root->ino_cache_lock);
+ if (root->ino_cache_state != BTRFS_CACHE_FINISHED) {
+ ret = -1;
+ spin_unlock(&root->ino_cache_lock);
+ goto out_put;
+ }
+ spin_unlock(&root->ino_cache_lock);
+
+ spin_lock(&ctl->tree_lock);
+ prealloc = sizeof(struct btrfs_free_space) * ctl->free_extents;
+ prealloc = ALIGN(prealloc, PAGE_SIZE);
+ prealloc += ctl->total_bitmaps * PAGE_SIZE;
+ spin_unlock(&ctl->tree_lock);
+
+ /* Just to make sure we have enough space */
+ prealloc += 8 * PAGE_SIZE;
+
+ ret = btrfs_delalloc_reserve_space(inode, &data_reserved, 0, prealloc);
+ if (ret)
+ goto out_put;
+
+ ret = btrfs_prealloc_file_range_trans(inode, trans, 0, 0, prealloc,
+ prealloc, prealloc, &alloc_hint);
+ if (ret) {
+ btrfs_delalloc_release_extents(BTRFS_I(inode), prealloc, true);
+ goto out_put;
+ }
+
+ ret = btrfs_write_out_ino_cache(root, trans, path, inode);
+ btrfs_delalloc_release_extents(BTRFS_I(inode), prealloc, false);
+out_put:
+ iput(inode);
+out_release:
+ trace_btrfs_space_reservation(fs_info, "ino_cache", trans->transid,
+ trans->bytes_reserved, 0);
+ btrfs_block_rsv_release(fs_info, trans->block_rsv,
+ trans->bytes_reserved);
+out:
+ trans->block_rsv = rsv;
+ trans->bytes_reserved = num_bytes;
+
+ btrfs_free_path(path);
+ extent_changeset_free(data_reserved);
+ return ret;
+}
+
+int btrfs_find_highest_objectid(struct btrfs_root *root, u64 *objectid)
+{
+ struct btrfs_path *path;
+ int ret;
+ struct extent_buffer *l;
+ struct btrfs_key search_key;
+ struct btrfs_key found_key;
+ int slot;
+
+ path = btrfs_alloc_path();
+ if (!path)
+ return -ENOMEM;
+
+ search_key.objectid = BTRFS_LAST_FREE_OBJECTID;
+ search_key.type = -1;
+ search_key.offset = (u64)-1;
+ ret = btrfs_search_slot(NULL, root, &search_key, path, 0, 0);
+ if (ret < 0)
+ goto error;
+ BUG_ON(ret == 0); /* Corruption */
+ if (path->slots[0] > 0) {
+ slot = path->slots[0] - 1;
+ l = path->nodes[0];
+ btrfs_item_key_to_cpu(l, &found_key, slot);
+ *objectid = max_t(u64, found_key.objectid,
+ BTRFS_FIRST_FREE_OBJECTID - 1);
+ } else {
+ *objectid = BTRFS_FIRST_FREE_OBJECTID - 1;
+ }
+ ret = 0;
+error:
+ btrfs_free_path(path);
+ return ret;
+}
+
+int btrfs_find_free_objectid(struct btrfs_root *root, u64 *objectid)
+{
+ int ret;
+ mutex_lock(&root->objectid_mutex);
+
+ if (unlikely(root->highest_objectid >= BTRFS_LAST_FREE_OBJECTID)) {
+ btrfs_warn(root->fs_info,
+ "the objectid of root %llu reaches its highest value",
+ root->root_key.objectid);
+ ret = -ENOSPC;
+ goto out;
+ }
+
+ *objectid = ++root->highest_objectid;
+ ret = 0;
+out:
+ mutex_unlock(&root->objectid_mutex);
+ return ret;
+}