v4.19.13 snapshot.
diff --git a/fs/xfs/xfs_icache.c b/fs/xfs/xfs_icache.c
new file mode 100644
index 0000000..245483c
--- /dev/null
+++ b/fs/xfs/xfs_icache.c
@@ -0,0 +1,1832 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2000-2005 Silicon Graphics, Inc.
+ * All Rights Reserved.
+ */
+#include "xfs.h"
+#include "xfs_fs.h"
+#include "xfs_format.h"
+#include "xfs_log_format.h"
+#include "xfs_trans_resv.h"
+#include "xfs_sb.h"
+#include "xfs_mount.h"
+#include "xfs_inode.h"
+#include "xfs_error.h"
+#include "xfs_trans.h"
+#include "xfs_trans_priv.h"
+#include "xfs_inode_item.h"
+#include "xfs_quota.h"
+#include "xfs_trace.h"
+#include "xfs_icache.h"
+#include "xfs_bmap_util.h"
+#include "xfs_dquot_item.h"
+#include "xfs_dquot.h"
+#include "xfs_reflink.h"
+
+#include <linux/kthread.h>
+#include <linux/freezer.h>
+#include <linux/iversion.h>
+
+/*
+ * Allocate and initialise an xfs_inode.
+ */
+struct xfs_inode *
+xfs_inode_alloc(
+ struct xfs_mount *mp,
+ xfs_ino_t ino)
+{
+ struct xfs_inode *ip;
+
+ /*
+ * if this didn't occur in transactions, we could use
+ * KM_MAYFAIL and return NULL here on ENOMEM. Set the
+ * code up to do this anyway.
+ */
+ ip = kmem_zone_alloc(xfs_inode_zone, KM_SLEEP);
+ if (!ip)
+ return NULL;
+ if (inode_init_always(mp->m_super, VFS_I(ip))) {
+ kmem_zone_free(xfs_inode_zone, ip);
+ return NULL;
+ }
+
+ /* VFS doesn't initialise i_mode! */
+ VFS_I(ip)->i_mode = 0;
+
+ XFS_STATS_INC(mp, vn_active);
+ ASSERT(atomic_read(&ip->i_pincount) == 0);
+ ASSERT(!xfs_isiflocked(ip));
+ ASSERT(ip->i_ino == 0);
+
+ /* initialise the xfs inode */
+ ip->i_ino = ino;
+ ip->i_mount = mp;
+ memset(&ip->i_imap, 0, sizeof(struct xfs_imap));
+ ip->i_afp = NULL;
+ ip->i_cowfp = NULL;
+ ip->i_cnextents = 0;
+ ip->i_cformat = XFS_DINODE_FMT_EXTENTS;
+ memset(&ip->i_df, 0, sizeof(ip->i_df));
+ ip->i_flags = 0;
+ ip->i_delayed_blks = 0;
+ memset(&ip->i_d, 0, sizeof(ip->i_d));
+
+ return ip;
+}
+
+STATIC void
+xfs_inode_free_callback(
+ struct rcu_head *head)
+{
+ struct inode *inode = container_of(head, struct inode, i_rcu);
+ struct xfs_inode *ip = XFS_I(inode);
+
+ switch (VFS_I(ip)->i_mode & S_IFMT) {
+ case S_IFREG:
+ case S_IFDIR:
+ case S_IFLNK:
+ xfs_idestroy_fork(ip, XFS_DATA_FORK);
+ break;
+ }
+
+ if (ip->i_afp)
+ xfs_idestroy_fork(ip, XFS_ATTR_FORK);
+ if (ip->i_cowfp)
+ xfs_idestroy_fork(ip, XFS_COW_FORK);
+
+ if (ip->i_itemp) {
+ ASSERT(!test_bit(XFS_LI_IN_AIL,
+ &ip->i_itemp->ili_item.li_flags));
+ xfs_inode_item_destroy(ip);
+ ip->i_itemp = NULL;
+ }
+
+ kmem_zone_free(xfs_inode_zone, ip);
+}
+
+static void
+__xfs_inode_free(
+ struct xfs_inode *ip)
+{
+ /* asserts to verify all state is correct here */
+ ASSERT(atomic_read(&ip->i_pincount) == 0);
+ XFS_STATS_DEC(ip->i_mount, vn_active);
+
+ call_rcu(&VFS_I(ip)->i_rcu, xfs_inode_free_callback);
+}
+
+void
+xfs_inode_free(
+ struct xfs_inode *ip)
+{
+ ASSERT(!xfs_isiflocked(ip));
+
+ /*
+ * Because we use RCU freeing we need to ensure the inode always
+ * appears to be reclaimed with an invalid inode number when in the
+ * free state. The ip->i_flags_lock provides the barrier against lookup
+ * races.
+ */
+ spin_lock(&ip->i_flags_lock);
+ ip->i_flags = XFS_IRECLAIM;
+ ip->i_ino = 0;
+ spin_unlock(&ip->i_flags_lock);
+
+ __xfs_inode_free(ip);
+}
+
+/*
+ * Queue a new inode reclaim pass if there are reclaimable inodes and there
+ * isn't a reclaim pass already in progress. By default it runs every 5s based
+ * on the xfs periodic sync default of 30s. Perhaps this should have it's own
+ * tunable, but that can be done if this method proves to be ineffective or too
+ * aggressive.
+ */
+static void
+xfs_reclaim_work_queue(
+ struct xfs_mount *mp)
+{
+
+ rcu_read_lock();
+ if (radix_tree_tagged(&mp->m_perag_tree, XFS_ICI_RECLAIM_TAG)) {
+ queue_delayed_work(mp->m_reclaim_workqueue, &mp->m_reclaim_work,
+ msecs_to_jiffies(xfs_syncd_centisecs / 6 * 10));
+ }
+ rcu_read_unlock();
+}
+
+/*
+ * This is a fast pass over the inode cache to try to get reclaim moving on as
+ * many inodes as possible in a short period of time. It kicks itself every few
+ * seconds, as well as being kicked by the inode cache shrinker when memory
+ * goes low. It scans as quickly as possible avoiding locked inodes or those
+ * already being flushed, and once done schedules a future pass.
+ */
+void
+xfs_reclaim_worker(
+ struct work_struct *work)
+{
+ struct xfs_mount *mp = container_of(to_delayed_work(work),
+ struct xfs_mount, m_reclaim_work);
+
+ xfs_reclaim_inodes(mp, SYNC_TRYLOCK);
+ xfs_reclaim_work_queue(mp);
+}
+
+static void
+xfs_perag_set_reclaim_tag(
+ struct xfs_perag *pag)
+{
+ struct xfs_mount *mp = pag->pag_mount;
+
+ lockdep_assert_held(&pag->pag_ici_lock);
+ if (pag->pag_ici_reclaimable++)
+ return;
+
+ /* propagate the reclaim tag up into the perag radix tree */
+ spin_lock(&mp->m_perag_lock);
+ radix_tree_tag_set(&mp->m_perag_tree, pag->pag_agno,
+ XFS_ICI_RECLAIM_TAG);
+ spin_unlock(&mp->m_perag_lock);
+
+ /* schedule periodic background inode reclaim */
+ xfs_reclaim_work_queue(mp);
+
+ trace_xfs_perag_set_reclaim(mp, pag->pag_agno, -1, _RET_IP_);
+}
+
+static void
+xfs_perag_clear_reclaim_tag(
+ struct xfs_perag *pag)
+{
+ struct xfs_mount *mp = pag->pag_mount;
+
+ lockdep_assert_held(&pag->pag_ici_lock);
+ if (--pag->pag_ici_reclaimable)
+ return;
+
+ /* clear the reclaim tag from the perag radix tree */
+ spin_lock(&mp->m_perag_lock);
+ radix_tree_tag_clear(&mp->m_perag_tree, pag->pag_agno,
+ XFS_ICI_RECLAIM_TAG);
+ spin_unlock(&mp->m_perag_lock);
+ trace_xfs_perag_clear_reclaim(mp, pag->pag_agno, -1, _RET_IP_);
+}
+
+
+/*
+ * We set the inode flag atomically with the radix tree tag.
+ * Once we get tag lookups on the radix tree, this inode flag
+ * can go away.
+ */
+void
+xfs_inode_set_reclaim_tag(
+ struct xfs_inode *ip)
+{
+ struct xfs_mount *mp = ip->i_mount;
+ struct xfs_perag *pag;
+
+ pag = xfs_perag_get(mp, XFS_INO_TO_AGNO(mp, ip->i_ino));
+ spin_lock(&pag->pag_ici_lock);
+ spin_lock(&ip->i_flags_lock);
+
+ radix_tree_tag_set(&pag->pag_ici_root, XFS_INO_TO_AGINO(mp, ip->i_ino),
+ XFS_ICI_RECLAIM_TAG);
+ xfs_perag_set_reclaim_tag(pag);
+ __xfs_iflags_set(ip, XFS_IRECLAIMABLE);
+
+ spin_unlock(&ip->i_flags_lock);
+ spin_unlock(&pag->pag_ici_lock);
+ xfs_perag_put(pag);
+}
+
+STATIC void
+xfs_inode_clear_reclaim_tag(
+ struct xfs_perag *pag,
+ xfs_ino_t ino)
+{
+ radix_tree_tag_clear(&pag->pag_ici_root,
+ XFS_INO_TO_AGINO(pag->pag_mount, ino),
+ XFS_ICI_RECLAIM_TAG);
+ xfs_perag_clear_reclaim_tag(pag);
+}
+
+static void
+xfs_inew_wait(
+ struct xfs_inode *ip)
+{
+ wait_queue_head_t *wq = bit_waitqueue(&ip->i_flags, __XFS_INEW_BIT);
+ DEFINE_WAIT_BIT(wait, &ip->i_flags, __XFS_INEW_BIT);
+
+ do {
+ prepare_to_wait(wq, &wait.wq_entry, TASK_UNINTERRUPTIBLE);
+ if (!xfs_iflags_test(ip, XFS_INEW))
+ break;
+ schedule();
+ } while (true);
+ finish_wait(wq, &wait.wq_entry);
+}
+
+/*
+ * When we recycle a reclaimable inode, we need to re-initialise the VFS inode
+ * part of the structure. This is made more complex by the fact we store
+ * information about the on-disk values in the VFS inode and so we can't just
+ * overwrite the values unconditionally. Hence we save the parameters we
+ * need to retain across reinitialisation, and rewrite them into the VFS inode
+ * after reinitialisation even if it fails.
+ */
+static int
+xfs_reinit_inode(
+ struct xfs_mount *mp,
+ struct inode *inode)
+{
+ int error;
+ uint32_t nlink = inode->i_nlink;
+ uint32_t generation = inode->i_generation;
+ uint64_t version = inode_peek_iversion(inode);
+ umode_t mode = inode->i_mode;
+ dev_t dev = inode->i_rdev;
+
+ error = inode_init_always(mp->m_super, inode);
+
+ set_nlink(inode, nlink);
+ inode->i_generation = generation;
+ inode_set_iversion_queried(inode, version);
+ inode->i_mode = mode;
+ inode->i_rdev = dev;
+ return error;
+}
+
+/*
+ * If we are allocating a new inode, then check what was returned is
+ * actually a free, empty inode. If we are not allocating an inode,
+ * then check we didn't find a free inode.
+ *
+ * Returns:
+ * 0 if the inode free state matches the lookup context
+ * -ENOENT if the inode is free and we are not allocating
+ * -EFSCORRUPTED if there is any state mismatch at all
+ */
+static int
+xfs_iget_check_free_state(
+ struct xfs_inode *ip,
+ int flags)
+{
+ if (flags & XFS_IGET_CREATE) {
+ /* should be a free inode */
+ if (VFS_I(ip)->i_mode != 0) {
+ xfs_warn(ip->i_mount,
+"Corruption detected! Free inode 0x%llx not marked free! (mode 0x%x)",
+ ip->i_ino, VFS_I(ip)->i_mode);
+ return -EFSCORRUPTED;
+ }
+
+ if (ip->i_d.di_nblocks != 0) {
+ xfs_warn(ip->i_mount,
+"Corruption detected! Free inode 0x%llx has blocks allocated!",
+ ip->i_ino);
+ return -EFSCORRUPTED;
+ }
+ return 0;
+ }
+
+ /* should be an allocated inode */
+ if (VFS_I(ip)->i_mode == 0)
+ return -ENOENT;
+
+ return 0;
+}
+
+/*
+ * Check the validity of the inode we just found it the cache
+ */
+static int
+xfs_iget_cache_hit(
+ struct xfs_perag *pag,
+ struct xfs_inode *ip,
+ xfs_ino_t ino,
+ int flags,
+ int lock_flags) __releases(RCU)
+{
+ struct inode *inode = VFS_I(ip);
+ struct xfs_mount *mp = ip->i_mount;
+ int error;
+
+ /*
+ * check for re-use of an inode within an RCU grace period due to the
+ * radix tree nodes not being updated yet. We monitor for this by
+ * setting the inode number to zero before freeing the inode structure.
+ * If the inode has been reallocated and set up, then the inode number
+ * will not match, so check for that, too.
+ */
+ spin_lock(&ip->i_flags_lock);
+ if (ip->i_ino != ino) {
+ trace_xfs_iget_skip(ip);
+ XFS_STATS_INC(mp, xs_ig_frecycle);
+ error = -EAGAIN;
+ goto out_error;
+ }
+
+
+ /*
+ * If we are racing with another cache hit that is currently
+ * instantiating this inode or currently recycling it out of
+ * reclaimabe state, wait for the initialisation to complete
+ * before continuing.
+ *
+ * XXX(hch): eventually we should do something equivalent to
+ * wait_on_inode to wait for these flags to be cleared
+ * instead of polling for it.
+ */
+ if (ip->i_flags & (XFS_INEW|XFS_IRECLAIM)) {
+ trace_xfs_iget_skip(ip);
+ XFS_STATS_INC(mp, xs_ig_frecycle);
+ error = -EAGAIN;
+ goto out_error;
+ }
+
+ /*
+ * Check the inode free state is valid. This also detects lookup
+ * racing with unlinks.
+ */
+ error = xfs_iget_check_free_state(ip, flags);
+ if (error)
+ goto out_error;
+
+ /*
+ * If IRECLAIMABLE is set, we've torn down the VFS inode already.
+ * Need to carefully get it back into useable state.
+ */
+ if (ip->i_flags & XFS_IRECLAIMABLE) {
+ trace_xfs_iget_reclaim(ip);
+
+ if (flags & XFS_IGET_INCORE) {
+ error = -EAGAIN;
+ goto out_error;
+ }
+
+ /*
+ * We need to set XFS_IRECLAIM to prevent xfs_reclaim_inode
+ * from stomping over us while we recycle the inode. We can't
+ * clear the radix tree reclaimable tag yet as it requires
+ * pag_ici_lock to be held exclusive.
+ */
+ ip->i_flags |= XFS_IRECLAIM;
+
+ spin_unlock(&ip->i_flags_lock);
+ rcu_read_unlock();
+
+ error = xfs_reinit_inode(mp, inode);
+ if (error) {
+ bool wake;
+ /*
+ * Re-initializing the inode failed, and we are in deep
+ * trouble. Try to re-add it to the reclaim list.
+ */
+ rcu_read_lock();
+ spin_lock(&ip->i_flags_lock);
+ wake = !!__xfs_iflags_test(ip, XFS_INEW);
+ ip->i_flags &= ~(XFS_INEW | XFS_IRECLAIM);
+ if (wake)
+ wake_up_bit(&ip->i_flags, __XFS_INEW_BIT);
+ ASSERT(ip->i_flags & XFS_IRECLAIMABLE);
+ trace_xfs_iget_reclaim_fail(ip);
+ goto out_error;
+ }
+
+ spin_lock(&pag->pag_ici_lock);
+ spin_lock(&ip->i_flags_lock);
+
+ /*
+ * Clear the per-lifetime state in the inode as we are now
+ * effectively a new inode and need to return to the initial
+ * state before reuse occurs.
+ */
+ ip->i_flags &= ~XFS_IRECLAIM_RESET_FLAGS;
+ ip->i_flags |= XFS_INEW;
+ xfs_inode_clear_reclaim_tag(pag, ip->i_ino);
+ inode->i_state = I_NEW;
+
+ ASSERT(!rwsem_is_locked(&inode->i_rwsem));
+ init_rwsem(&inode->i_rwsem);
+
+ spin_unlock(&ip->i_flags_lock);
+ spin_unlock(&pag->pag_ici_lock);
+ } else {
+ /* If the VFS inode is being torn down, pause and try again. */
+ if (!igrab(inode)) {
+ trace_xfs_iget_skip(ip);
+ error = -EAGAIN;
+ goto out_error;
+ }
+
+ /* We've got a live one. */
+ spin_unlock(&ip->i_flags_lock);
+ rcu_read_unlock();
+ trace_xfs_iget_hit(ip);
+ }
+
+ if (lock_flags != 0)
+ xfs_ilock(ip, lock_flags);
+
+ if (!(flags & XFS_IGET_INCORE))
+ xfs_iflags_clear(ip, XFS_ISTALE | XFS_IDONTCACHE);
+ XFS_STATS_INC(mp, xs_ig_found);
+
+ return 0;
+
+out_error:
+ spin_unlock(&ip->i_flags_lock);
+ rcu_read_unlock();
+ return error;
+}
+
+
+static int
+xfs_iget_cache_miss(
+ struct xfs_mount *mp,
+ struct xfs_perag *pag,
+ xfs_trans_t *tp,
+ xfs_ino_t ino,
+ struct xfs_inode **ipp,
+ int flags,
+ int lock_flags)
+{
+ struct xfs_inode *ip;
+ int error;
+ xfs_agino_t agino = XFS_INO_TO_AGINO(mp, ino);
+ int iflags;
+
+ ip = xfs_inode_alloc(mp, ino);
+ if (!ip)
+ return -ENOMEM;
+
+ error = xfs_iread(mp, tp, ip, flags);
+ if (error)
+ goto out_destroy;
+
+ if (!xfs_inode_verify_forks(ip)) {
+ error = -EFSCORRUPTED;
+ goto out_destroy;
+ }
+
+ trace_xfs_iget_miss(ip);
+
+
+ /*
+ * Check the inode free state is valid. This also detects lookup
+ * racing with unlinks.
+ */
+ error = xfs_iget_check_free_state(ip, flags);
+ if (error)
+ goto out_destroy;
+
+ /*
+ * Preload the radix tree so we can insert safely under the
+ * write spinlock. Note that we cannot sleep inside the preload
+ * region. Since we can be called from transaction context, don't
+ * recurse into the file system.
+ */
+ if (radix_tree_preload(GFP_NOFS)) {
+ error = -EAGAIN;
+ goto out_destroy;
+ }
+
+ /*
+ * Because the inode hasn't been added to the radix-tree yet it can't
+ * be found by another thread, so we can do the non-sleeping lock here.
+ */
+ if (lock_flags) {
+ if (!xfs_ilock_nowait(ip, lock_flags))
+ BUG();
+ }
+
+ /*
+ * These values must be set before inserting the inode into the radix
+ * tree as the moment it is inserted a concurrent lookup (allowed by the
+ * RCU locking mechanism) can find it and that lookup must see that this
+ * is an inode currently under construction (i.e. that XFS_INEW is set).
+ * The ip->i_flags_lock that protects the XFS_INEW flag forms the
+ * memory barrier that ensures this detection works correctly at lookup
+ * time.
+ */
+ iflags = XFS_INEW;
+ if (flags & XFS_IGET_DONTCACHE)
+ iflags |= XFS_IDONTCACHE;
+ ip->i_udquot = NULL;
+ ip->i_gdquot = NULL;
+ ip->i_pdquot = NULL;
+ xfs_iflags_set(ip, iflags);
+
+ /* insert the new inode */
+ spin_lock(&pag->pag_ici_lock);
+ error = radix_tree_insert(&pag->pag_ici_root, agino, ip);
+ if (unlikely(error)) {
+ WARN_ON(error != -EEXIST);
+ XFS_STATS_INC(mp, xs_ig_dup);
+ error = -EAGAIN;
+ goto out_preload_end;
+ }
+ spin_unlock(&pag->pag_ici_lock);
+ radix_tree_preload_end();
+
+ *ipp = ip;
+ return 0;
+
+out_preload_end:
+ spin_unlock(&pag->pag_ici_lock);
+ radix_tree_preload_end();
+ if (lock_flags)
+ xfs_iunlock(ip, lock_flags);
+out_destroy:
+ __destroy_inode(VFS_I(ip));
+ xfs_inode_free(ip);
+ return error;
+}
+
+/*
+ * Look up an inode by number in the given file system.
+ * The inode is looked up in the cache held in each AG.
+ * If the inode is found in the cache, initialise the vfs inode
+ * if necessary.
+ *
+ * If it is not in core, read it in from the file system's device,
+ * add it to the cache and initialise the vfs inode.
+ *
+ * The inode is locked according to the value of the lock_flags parameter.
+ * This flag parameter indicates how and if the inode's IO lock and inode lock
+ * should be taken.
+ *
+ * mp -- the mount point structure for the current file system. It points
+ * to the inode hash table.
+ * tp -- a pointer to the current transaction if there is one. This is
+ * simply passed through to the xfs_iread() call.
+ * ino -- the number of the inode desired. This is the unique identifier
+ * within the file system for the inode being requested.
+ * lock_flags -- flags indicating how to lock the inode. See the comment
+ * for xfs_ilock() for a list of valid values.
+ */
+int
+xfs_iget(
+ xfs_mount_t *mp,
+ xfs_trans_t *tp,
+ xfs_ino_t ino,
+ uint flags,
+ uint lock_flags,
+ xfs_inode_t **ipp)
+{
+ xfs_inode_t *ip;
+ int error;
+ xfs_perag_t *pag;
+ xfs_agino_t agino;
+
+ /*
+ * xfs_reclaim_inode() uses the ILOCK to ensure an inode
+ * doesn't get freed while it's being referenced during a
+ * radix tree traversal here. It assumes this function
+ * aqcuires only the ILOCK (and therefore it has no need to
+ * involve the IOLOCK in this synchronization).
+ */
+ ASSERT((lock_flags & (XFS_IOLOCK_EXCL | XFS_IOLOCK_SHARED)) == 0);
+
+ /* reject inode numbers outside existing AGs */
+ if (!ino || XFS_INO_TO_AGNO(mp, ino) >= mp->m_sb.sb_agcount)
+ return -EINVAL;
+
+ XFS_STATS_INC(mp, xs_ig_attempts);
+
+ /* get the perag structure and ensure that it's inode capable */
+ pag = xfs_perag_get(mp, XFS_INO_TO_AGNO(mp, ino));
+ agino = XFS_INO_TO_AGINO(mp, ino);
+
+again:
+ error = 0;
+ rcu_read_lock();
+ ip = radix_tree_lookup(&pag->pag_ici_root, agino);
+
+ if (ip) {
+ error = xfs_iget_cache_hit(pag, ip, ino, flags, lock_flags);
+ if (error)
+ goto out_error_or_again;
+ } else {
+ rcu_read_unlock();
+ if (flags & XFS_IGET_INCORE) {
+ error = -ENODATA;
+ goto out_error_or_again;
+ }
+ XFS_STATS_INC(mp, xs_ig_missed);
+
+ error = xfs_iget_cache_miss(mp, pag, tp, ino, &ip,
+ flags, lock_flags);
+ if (error)
+ goto out_error_or_again;
+ }
+ xfs_perag_put(pag);
+
+ *ipp = ip;
+
+ /*
+ * If we have a real type for an on-disk inode, we can setup the inode
+ * now. If it's a new inode being created, xfs_ialloc will handle it.
+ */
+ if (xfs_iflags_test(ip, XFS_INEW) && VFS_I(ip)->i_mode != 0)
+ xfs_setup_existing_inode(ip);
+ return 0;
+
+out_error_or_again:
+ if (!(flags & XFS_IGET_INCORE) && error == -EAGAIN) {
+ delay(1);
+ goto again;
+ }
+ xfs_perag_put(pag);
+ return error;
+}
+
+/*
+ * "Is this a cached inode that's also allocated?"
+ *
+ * Look up an inode by number in the given file system. If the inode is
+ * in cache and isn't in purgatory, return 1 if the inode is allocated
+ * and 0 if it is not. For all other cases (not in cache, being torn
+ * down, etc.), return a negative error code.
+ *
+ * The caller has to prevent inode allocation and freeing activity,
+ * presumably by locking the AGI buffer. This is to ensure that an
+ * inode cannot transition from allocated to freed until the caller is
+ * ready to allow that. If the inode is in an intermediate state (new,
+ * reclaimable, or being reclaimed), -EAGAIN will be returned; if the
+ * inode is not in the cache, -ENOENT will be returned. The caller must
+ * deal with these scenarios appropriately.
+ *
+ * This is a specialized use case for the online scrubber; if you're
+ * reading this, you probably want xfs_iget.
+ */
+int
+xfs_icache_inode_is_allocated(
+ struct xfs_mount *mp,
+ struct xfs_trans *tp,
+ xfs_ino_t ino,
+ bool *inuse)
+{
+ struct xfs_inode *ip;
+ int error;
+
+ error = xfs_iget(mp, tp, ino, XFS_IGET_INCORE, 0, &ip);
+ if (error)
+ return error;
+
+ *inuse = !!(VFS_I(ip)->i_mode);
+ xfs_irele(ip);
+ return 0;
+}
+
+/*
+ * The inode lookup is done in batches to keep the amount of lock traffic and
+ * radix tree lookups to a minimum. The batch size is a trade off between
+ * lookup reduction and stack usage. This is in the reclaim path, so we can't
+ * be too greedy.
+ */
+#define XFS_LOOKUP_BATCH 32
+
+STATIC int
+xfs_inode_ag_walk_grab(
+ struct xfs_inode *ip,
+ int flags)
+{
+ struct inode *inode = VFS_I(ip);
+ bool newinos = !!(flags & XFS_AGITER_INEW_WAIT);
+
+ ASSERT(rcu_read_lock_held());
+
+ /*
+ * check for stale RCU freed inode
+ *
+ * If the inode has been reallocated, it doesn't matter if it's not in
+ * the AG we are walking - we are walking for writeback, so if it
+ * passes all the "valid inode" checks and is dirty, then we'll write
+ * it back anyway. If it has been reallocated and still being
+ * initialised, the XFS_INEW check below will catch it.
+ */
+ spin_lock(&ip->i_flags_lock);
+ if (!ip->i_ino)
+ goto out_unlock_noent;
+
+ /* avoid new or reclaimable inodes. Leave for reclaim code to flush */
+ if ((!newinos && __xfs_iflags_test(ip, XFS_INEW)) ||
+ __xfs_iflags_test(ip, XFS_IRECLAIMABLE | XFS_IRECLAIM))
+ goto out_unlock_noent;
+ spin_unlock(&ip->i_flags_lock);
+
+ /* nothing to sync during shutdown */
+ if (XFS_FORCED_SHUTDOWN(ip->i_mount))
+ return -EFSCORRUPTED;
+
+ /* If we can't grab the inode, it must on it's way to reclaim. */
+ if (!igrab(inode))
+ return -ENOENT;
+
+ /* inode is valid */
+ return 0;
+
+out_unlock_noent:
+ spin_unlock(&ip->i_flags_lock);
+ return -ENOENT;
+}
+
+STATIC int
+xfs_inode_ag_walk(
+ struct xfs_mount *mp,
+ struct xfs_perag *pag,
+ int (*execute)(struct xfs_inode *ip, int flags,
+ void *args),
+ int flags,
+ void *args,
+ int tag,
+ int iter_flags)
+{
+ uint32_t first_index;
+ int last_error = 0;
+ int skipped;
+ int done;
+ int nr_found;
+
+restart:
+ done = 0;
+ skipped = 0;
+ first_index = 0;
+ nr_found = 0;
+ do {
+ struct xfs_inode *batch[XFS_LOOKUP_BATCH];
+ int error = 0;
+ int i;
+
+ rcu_read_lock();
+
+ if (tag == -1)
+ nr_found = radix_tree_gang_lookup(&pag->pag_ici_root,
+ (void **)batch, first_index,
+ XFS_LOOKUP_BATCH);
+ else
+ nr_found = radix_tree_gang_lookup_tag(
+ &pag->pag_ici_root,
+ (void **) batch, first_index,
+ XFS_LOOKUP_BATCH, tag);
+
+ if (!nr_found) {
+ rcu_read_unlock();
+ break;
+ }
+
+ /*
+ * Grab the inodes before we drop the lock. if we found
+ * nothing, nr == 0 and the loop will be skipped.
+ */
+ for (i = 0; i < nr_found; i++) {
+ struct xfs_inode *ip = batch[i];
+
+ if (done || xfs_inode_ag_walk_grab(ip, iter_flags))
+ batch[i] = NULL;
+
+ /*
+ * Update the index for the next lookup. Catch
+ * overflows into the next AG range which can occur if
+ * we have inodes in the last block of the AG and we
+ * are currently pointing to the last inode.
+ *
+ * Because we may see inodes that are from the wrong AG
+ * due to RCU freeing and reallocation, only update the
+ * index if it lies in this AG. It was a race that lead
+ * us to see this inode, so another lookup from the
+ * same index will not find it again.
+ */
+ if (XFS_INO_TO_AGNO(mp, ip->i_ino) != pag->pag_agno)
+ continue;
+ first_index = XFS_INO_TO_AGINO(mp, ip->i_ino + 1);
+ if (first_index < XFS_INO_TO_AGINO(mp, ip->i_ino))
+ done = 1;
+ }
+
+ /* unlock now we've grabbed the inodes. */
+ rcu_read_unlock();
+
+ for (i = 0; i < nr_found; i++) {
+ if (!batch[i])
+ continue;
+ if ((iter_flags & XFS_AGITER_INEW_WAIT) &&
+ xfs_iflags_test(batch[i], XFS_INEW))
+ xfs_inew_wait(batch[i]);
+ error = execute(batch[i], flags, args);
+ xfs_irele(batch[i]);
+ if (error == -EAGAIN) {
+ skipped++;
+ continue;
+ }
+ if (error && last_error != -EFSCORRUPTED)
+ last_error = error;
+ }
+
+ /* bail out if the filesystem is corrupted. */
+ if (error == -EFSCORRUPTED)
+ break;
+
+ cond_resched();
+
+ } while (nr_found && !done);
+
+ if (skipped) {
+ delay(1);
+ goto restart;
+ }
+ return last_error;
+}
+
+/*
+ * Background scanning to trim post-EOF preallocated space. This is queued
+ * based on the 'speculative_prealloc_lifetime' tunable (5m by default).
+ */
+void
+xfs_queue_eofblocks(
+ struct xfs_mount *mp)
+{
+ rcu_read_lock();
+ if (radix_tree_tagged(&mp->m_perag_tree, XFS_ICI_EOFBLOCKS_TAG))
+ queue_delayed_work(mp->m_eofblocks_workqueue,
+ &mp->m_eofblocks_work,
+ msecs_to_jiffies(xfs_eofb_secs * 1000));
+ rcu_read_unlock();
+}
+
+void
+xfs_eofblocks_worker(
+ struct work_struct *work)
+{
+ struct xfs_mount *mp = container_of(to_delayed_work(work),
+ struct xfs_mount, m_eofblocks_work);
+ xfs_icache_free_eofblocks(mp, NULL);
+ xfs_queue_eofblocks(mp);
+}
+
+/*
+ * Background scanning to trim preallocated CoW space. This is queued
+ * based on the 'speculative_cow_prealloc_lifetime' tunable (5m by default).
+ * (We'll just piggyback on the post-EOF prealloc space workqueue.)
+ */
+void
+xfs_queue_cowblocks(
+ struct xfs_mount *mp)
+{
+ rcu_read_lock();
+ if (radix_tree_tagged(&mp->m_perag_tree, XFS_ICI_COWBLOCKS_TAG))
+ queue_delayed_work(mp->m_eofblocks_workqueue,
+ &mp->m_cowblocks_work,
+ msecs_to_jiffies(xfs_cowb_secs * 1000));
+ rcu_read_unlock();
+}
+
+void
+xfs_cowblocks_worker(
+ struct work_struct *work)
+{
+ struct xfs_mount *mp = container_of(to_delayed_work(work),
+ struct xfs_mount, m_cowblocks_work);
+ xfs_icache_free_cowblocks(mp, NULL);
+ xfs_queue_cowblocks(mp);
+}
+
+int
+xfs_inode_ag_iterator_flags(
+ struct xfs_mount *mp,
+ int (*execute)(struct xfs_inode *ip, int flags,
+ void *args),
+ int flags,
+ void *args,
+ int iter_flags)
+{
+ struct xfs_perag *pag;
+ int error = 0;
+ int last_error = 0;
+ xfs_agnumber_t ag;
+
+ ag = 0;
+ while ((pag = xfs_perag_get(mp, ag))) {
+ ag = pag->pag_agno + 1;
+ error = xfs_inode_ag_walk(mp, pag, execute, flags, args, -1,
+ iter_flags);
+ xfs_perag_put(pag);
+ if (error) {
+ last_error = error;
+ if (error == -EFSCORRUPTED)
+ break;
+ }
+ }
+ return last_error;
+}
+
+int
+xfs_inode_ag_iterator(
+ struct xfs_mount *mp,
+ int (*execute)(struct xfs_inode *ip, int flags,
+ void *args),
+ int flags,
+ void *args)
+{
+ return xfs_inode_ag_iterator_flags(mp, execute, flags, args, 0);
+}
+
+int
+xfs_inode_ag_iterator_tag(
+ struct xfs_mount *mp,
+ int (*execute)(struct xfs_inode *ip, int flags,
+ void *args),
+ int flags,
+ void *args,
+ int tag)
+{
+ struct xfs_perag *pag;
+ int error = 0;
+ int last_error = 0;
+ xfs_agnumber_t ag;
+
+ ag = 0;
+ while ((pag = xfs_perag_get_tag(mp, ag, tag))) {
+ ag = pag->pag_agno + 1;
+ error = xfs_inode_ag_walk(mp, pag, execute, flags, args, tag,
+ 0);
+ xfs_perag_put(pag);
+ if (error) {
+ last_error = error;
+ if (error == -EFSCORRUPTED)
+ break;
+ }
+ }
+ return last_error;
+}
+
+/*
+ * Grab the inode for reclaim exclusively.
+ * Return 0 if we grabbed it, non-zero otherwise.
+ */
+STATIC int
+xfs_reclaim_inode_grab(
+ struct xfs_inode *ip,
+ int flags)
+{
+ ASSERT(rcu_read_lock_held());
+
+ /* quick check for stale RCU freed inode */
+ if (!ip->i_ino)
+ return 1;
+
+ /*
+ * If we are asked for non-blocking operation, do unlocked checks to
+ * see if the inode already is being flushed or in reclaim to avoid
+ * lock traffic.
+ */
+ if ((flags & SYNC_TRYLOCK) &&
+ __xfs_iflags_test(ip, XFS_IFLOCK | XFS_IRECLAIM))
+ return 1;
+
+ /*
+ * The radix tree lock here protects a thread in xfs_iget from racing
+ * with us starting reclaim on the inode. Once we have the
+ * XFS_IRECLAIM flag set it will not touch us.
+ *
+ * Due to RCU lookup, we may find inodes that have been freed and only
+ * have XFS_IRECLAIM set. Indeed, we may see reallocated inodes that
+ * aren't candidates for reclaim at all, so we must check the
+ * XFS_IRECLAIMABLE is set first before proceeding to reclaim.
+ */
+ spin_lock(&ip->i_flags_lock);
+ if (!__xfs_iflags_test(ip, XFS_IRECLAIMABLE) ||
+ __xfs_iflags_test(ip, XFS_IRECLAIM)) {
+ /* not a reclaim candidate. */
+ spin_unlock(&ip->i_flags_lock);
+ return 1;
+ }
+ __xfs_iflags_set(ip, XFS_IRECLAIM);
+ spin_unlock(&ip->i_flags_lock);
+ return 0;
+}
+
+/*
+ * Inodes in different states need to be treated differently. The following
+ * table lists the inode states and the reclaim actions necessary:
+ *
+ * inode state iflush ret required action
+ * --------------- ---------- ---------------
+ * bad - reclaim
+ * shutdown EIO unpin and reclaim
+ * clean, unpinned 0 reclaim
+ * stale, unpinned 0 reclaim
+ * clean, pinned(*) 0 requeue
+ * stale, pinned EAGAIN requeue
+ * dirty, async - requeue
+ * dirty, sync 0 reclaim
+ *
+ * (*) dgc: I don't think the clean, pinned state is possible but it gets
+ * handled anyway given the order of checks implemented.
+ *
+ * Also, because we get the flush lock first, we know that any inode that has
+ * been flushed delwri has had the flush completed by the time we check that
+ * the inode is clean.
+ *
+ * Note that because the inode is flushed delayed write by AIL pushing, the
+ * flush lock may already be held here and waiting on it can result in very
+ * long latencies. Hence for sync reclaims, where we wait on the flush lock,
+ * the caller should push the AIL first before trying to reclaim inodes to
+ * minimise the amount of time spent waiting. For background relaim, we only
+ * bother to reclaim clean inodes anyway.
+ *
+ * Hence the order of actions after gaining the locks should be:
+ * bad => reclaim
+ * shutdown => unpin and reclaim
+ * pinned, async => requeue
+ * pinned, sync => unpin
+ * stale => reclaim
+ * clean => reclaim
+ * dirty, async => requeue
+ * dirty, sync => flush, wait and reclaim
+ */
+STATIC int
+xfs_reclaim_inode(
+ struct xfs_inode *ip,
+ struct xfs_perag *pag,
+ int sync_mode)
+{
+ struct xfs_buf *bp = NULL;
+ xfs_ino_t ino = ip->i_ino; /* for radix_tree_delete */
+ int error;
+
+restart:
+ error = 0;
+ xfs_ilock(ip, XFS_ILOCK_EXCL);
+ if (!xfs_iflock_nowait(ip)) {
+ if (!(sync_mode & SYNC_WAIT))
+ goto out;
+ xfs_iflock(ip);
+ }
+
+ if (XFS_FORCED_SHUTDOWN(ip->i_mount)) {
+ xfs_iunpin_wait(ip);
+ /* xfs_iflush_abort() drops the flush lock */
+ xfs_iflush_abort(ip, false);
+ goto reclaim;
+ }
+ if (xfs_ipincount(ip)) {
+ if (!(sync_mode & SYNC_WAIT))
+ goto out_ifunlock;
+ xfs_iunpin_wait(ip);
+ }
+ if (xfs_iflags_test(ip, XFS_ISTALE) || xfs_inode_clean(ip)) {
+ xfs_ifunlock(ip);
+ goto reclaim;
+ }
+
+ /*
+ * Never flush out dirty data during non-blocking reclaim, as it would
+ * just contend with AIL pushing trying to do the same job.
+ */
+ if (!(sync_mode & SYNC_WAIT))
+ goto out_ifunlock;
+
+ /*
+ * Now we have an inode that needs flushing.
+ *
+ * Note that xfs_iflush will never block on the inode buffer lock, as
+ * xfs_ifree_cluster() can lock the inode buffer before it locks the
+ * ip->i_lock, and we are doing the exact opposite here. As a result,
+ * doing a blocking xfs_imap_to_bp() to get the cluster buffer would
+ * result in an ABBA deadlock with xfs_ifree_cluster().
+ *
+ * As xfs_ifree_cluser() must gather all inodes that are active in the
+ * cache to mark them stale, if we hit this case we don't actually want
+ * to do IO here - we want the inode marked stale so we can simply
+ * reclaim it. Hence if we get an EAGAIN error here, just unlock the
+ * inode, back off and try again. Hopefully the next pass through will
+ * see the stale flag set on the inode.
+ */
+ error = xfs_iflush(ip, &bp);
+ if (error == -EAGAIN) {
+ xfs_iunlock(ip, XFS_ILOCK_EXCL);
+ /* backoff longer than in xfs_ifree_cluster */
+ delay(2);
+ goto restart;
+ }
+
+ if (!error) {
+ error = xfs_bwrite(bp);
+ xfs_buf_relse(bp);
+ }
+
+reclaim:
+ ASSERT(!xfs_isiflocked(ip));
+
+ /*
+ * Because we use RCU freeing we need to ensure the inode always appears
+ * to be reclaimed with an invalid inode number when in the free state.
+ * We do this as early as possible under the ILOCK so that
+ * xfs_iflush_cluster() and xfs_ifree_cluster() can be guaranteed to
+ * detect races with us here. By doing this, we guarantee that once
+ * xfs_iflush_cluster() or xfs_ifree_cluster() has locked XFS_ILOCK that
+ * it will see either a valid inode that will serialise correctly, or it
+ * will see an invalid inode that it can skip.
+ */
+ spin_lock(&ip->i_flags_lock);
+ ip->i_flags = XFS_IRECLAIM;
+ ip->i_ino = 0;
+ spin_unlock(&ip->i_flags_lock);
+
+ xfs_iunlock(ip, XFS_ILOCK_EXCL);
+
+ XFS_STATS_INC(ip->i_mount, xs_ig_reclaims);
+ /*
+ * Remove the inode from the per-AG radix tree.
+ *
+ * Because radix_tree_delete won't complain even if the item was never
+ * added to the tree assert that it's been there before to catch
+ * problems with the inode life time early on.
+ */
+ spin_lock(&pag->pag_ici_lock);
+ if (!radix_tree_delete(&pag->pag_ici_root,
+ XFS_INO_TO_AGINO(ip->i_mount, ino)))
+ ASSERT(0);
+ xfs_perag_clear_reclaim_tag(pag);
+ spin_unlock(&pag->pag_ici_lock);
+
+ /*
+ * Here we do an (almost) spurious inode lock in order to coordinate
+ * with inode cache radix tree lookups. This is because the lookup
+ * can reference the inodes in the cache without taking references.
+ *
+ * We make that OK here by ensuring that we wait until the inode is
+ * unlocked after the lookup before we go ahead and free it.
+ */
+ xfs_ilock(ip, XFS_ILOCK_EXCL);
+ xfs_qm_dqdetach(ip);
+ xfs_iunlock(ip, XFS_ILOCK_EXCL);
+
+ __xfs_inode_free(ip);
+ return error;
+
+out_ifunlock:
+ xfs_ifunlock(ip);
+out:
+ xfs_iflags_clear(ip, XFS_IRECLAIM);
+ xfs_iunlock(ip, XFS_ILOCK_EXCL);
+ /*
+ * We could return -EAGAIN here to make reclaim rescan the inode tree in
+ * a short while. However, this just burns CPU time scanning the tree
+ * waiting for IO to complete and the reclaim work never goes back to
+ * the idle state. Instead, return 0 to let the next scheduled
+ * background reclaim attempt to reclaim the inode again.
+ */
+ return 0;
+}
+
+/*
+ * Walk the AGs and reclaim the inodes in them. Even if the filesystem is
+ * corrupted, we still want to try to reclaim all the inodes. If we don't,
+ * then a shut down during filesystem unmount reclaim walk leak all the
+ * unreclaimed inodes.
+ */
+STATIC int
+xfs_reclaim_inodes_ag(
+ struct xfs_mount *mp,
+ int flags,
+ int *nr_to_scan)
+{
+ struct xfs_perag *pag;
+ int error = 0;
+ int last_error = 0;
+ xfs_agnumber_t ag;
+ int trylock = flags & SYNC_TRYLOCK;
+ int skipped;
+
+restart:
+ ag = 0;
+ skipped = 0;
+ while ((pag = xfs_perag_get_tag(mp, ag, XFS_ICI_RECLAIM_TAG))) {
+ unsigned long first_index = 0;
+ int done = 0;
+ int nr_found = 0;
+
+ ag = pag->pag_agno + 1;
+
+ if (trylock) {
+ if (!mutex_trylock(&pag->pag_ici_reclaim_lock)) {
+ skipped++;
+ xfs_perag_put(pag);
+ continue;
+ }
+ first_index = pag->pag_ici_reclaim_cursor;
+ } else
+ mutex_lock(&pag->pag_ici_reclaim_lock);
+
+ do {
+ struct xfs_inode *batch[XFS_LOOKUP_BATCH];
+ int i;
+
+ rcu_read_lock();
+ nr_found = radix_tree_gang_lookup_tag(
+ &pag->pag_ici_root,
+ (void **)batch, first_index,
+ XFS_LOOKUP_BATCH,
+ XFS_ICI_RECLAIM_TAG);
+ if (!nr_found) {
+ done = 1;
+ rcu_read_unlock();
+ break;
+ }
+
+ /*
+ * Grab the inodes before we drop the lock. if we found
+ * nothing, nr == 0 and the loop will be skipped.
+ */
+ for (i = 0; i < nr_found; i++) {
+ struct xfs_inode *ip = batch[i];
+
+ if (done || xfs_reclaim_inode_grab(ip, flags))
+ batch[i] = NULL;
+
+ /*
+ * Update the index for the next lookup. Catch
+ * overflows into the next AG range which can
+ * occur if we have inodes in the last block of
+ * the AG and we are currently pointing to the
+ * last inode.
+ *
+ * Because we may see inodes that are from the
+ * wrong AG due to RCU freeing and
+ * reallocation, only update the index if it
+ * lies in this AG. It was a race that lead us
+ * to see this inode, so another lookup from
+ * the same index will not find it again.
+ */
+ if (XFS_INO_TO_AGNO(mp, ip->i_ino) !=
+ pag->pag_agno)
+ continue;
+ first_index = XFS_INO_TO_AGINO(mp, ip->i_ino + 1);
+ if (first_index < XFS_INO_TO_AGINO(mp, ip->i_ino))
+ done = 1;
+ }
+
+ /* unlock now we've grabbed the inodes. */
+ rcu_read_unlock();
+
+ for (i = 0; i < nr_found; i++) {
+ if (!batch[i])
+ continue;
+ error = xfs_reclaim_inode(batch[i], pag, flags);
+ if (error && last_error != -EFSCORRUPTED)
+ last_error = error;
+ }
+
+ *nr_to_scan -= XFS_LOOKUP_BATCH;
+
+ cond_resched();
+
+ } while (nr_found && !done && *nr_to_scan > 0);
+
+ if (trylock && !done)
+ pag->pag_ici_reclaim_cursor = first_index;
+ else
+ pag->pag_ici_reclaim_cursor = 0;
+ mutex_unlock(&pag->pag_ici_reclaim_lock);
+ xfs_perag_put(pag);
+ }
+
+ /*
+ * if we skipped any AG, and we still have scan count remaining, do
+ * another pass this time using blocking reclaim semantics (i.e
+ * waiting on the reclaim locks and ignoring the reclaim cursors). This
+ * ensure that when we get more reclaimers than AGs we block rather
+ * than spin trying to execute reclaim.
+ */
+ if (skipped && (flags & SYNC_WAIT) && *nr_to_scan > 0) {
+ trylock = 0;
+ goto restart;
+ }
+ return last_error;
+}
+
+int
+xfs_reclaim_inodes(
+ xfs_mount_t *mp,
+ int mode)
+{
+ int nr_to_scan = INT_MAX;
+
+ return xfs_reclaim_inodes_ag(mp, mode, &nr_to_scan);
+}
+
+/*
+ * Scan a certain number of inodes for reclaim.
+ *
+ * When called we make sure that there is a background (fast) inode reclaim in
+ * progress, while we will throttle the speed of reclaim via doing synchronous
+ * reclaim of inodes. That means if we come across dirty inodes, we wait for
+ * them to be cleaned, which we hope will not be very long due to the
+ * background walker having already kicked the IO off on those dirty inodes.
+ */
+long
+xfs_reclaim_inodes_nr(
+ struct xfs_mount *mp,
+ int nr_to_scan)
+{
+ /* kick background reclaimer and push the AIL */
+ xfs_reclaim_work_queue(mp);
+ xfs_ail_push_all(mp->m_ail);
+
+ return xfs_reclaim_inodes_ag(mp, SYNC_TRYLOCK | SYNC_WAIT, &nr_to_scan);
+}
+
+/*
+ * Return the number of reclaimable inodes in the filesystem for
+ * the shrinker to determine how much to reclaim.
+ */
+int
+xfs_reclaim_inodes_count(
+ struct xfs_mount *mp)
+{
+ struct xfs_perag *pag;
+ xfs_agnumber_t ag = 0;
+ int reclaimable = 0;
+
+ while ((pag = xfs_perag_get_tag(mp, ag, XFS_ICI_RECLAIM_TAG))) {
+ ag = pag->pag_agno + 1;
+ reclaimable += pag->pag_ici_reclaimable;
+ xfs_perag_put(pag);
+ }
+ return reclaimable;
+}
+
+STATIC int
+xfs_inode_match_id(
+ struct xfs_inode *ip,
+ struct xfs_eofblocks *eofb)
+{
+ if ((eofb->eof_flags & XFS_EOF_FLAGS_UID) &&
+ !uid_eq(VFS_I(ip)->i_uid, eofb->eof_uid))
+ return 0;
+
+ if ((eofb->eof_flags & XFS_EOF_FLAGS_GID) &&
+ !gid_eq(VFS_I(ip)->i_gid, eofb->eof_gid))
+ return 0;
+
+ if ((eofb->eof_flags & XFS_EOF_FLAGS_PRID) &&
+ xfs_get_projid(ip) != eofb->eof_prid)
+ return 0;
+
+ return 1;
+}
+
+/*
+ * A union-based inode filtering algorithm. Process the inode if any of the
+ * criteria match. This is for global/internal scans only.
+ */
+STATIC int
+xfs_inode_match_id_union(
+ struct xfs_inode *ip,
+ struct xfs_eofblocks *eofb)
+{
+ if ((eofb->eof_flags & XFS_EOF_FLAGS_UID) &&
+ uid_eq(VFS_I(ip)->i_uid, eofb->eof_uid))
+ return 1;
+
+ if ((eofb->eof_flags & XFS_EOF_FLAGS_GID) &&
+ gid_eq(VFS_I(ip)->i_gid, eofb->eof_gid))
+ return 1;
+
+ if ((eofb->eof_flags & XFS_EOF_FLAGS_PRID) &&
+ xfs_get_projid(ip) == eofb->eof_prid)
+ return 1;
+
+ return 0;
+}
+
+STATIC int
+xfs_inode_free_eofblocks(
+ struct xfs_inode *ip,
+ int flags,
+ void *args)
+{
+ int ret = 0;
+ struct xfs_eofblocks *eofb = args;
+ int match;
+
+ if (!xfs_can_free_eofblocks(ip, false)) {
+ /* inode could be preallocated or append-only */
+ trace_xfs_inode_free_eofblocks_invalid(ip);
+ xfs_inode_clear_eofblocks_tag(ip);
+ return 0;
+ }
+
+ /*
+ * If the mapping is dirty the operation can block and wait for some
+ * time. Unless we are waiting, skip it.
+ */
+ if (!(flags & SYNC_WAIT) &&
+ mapping_tagged(VFS_I(ip)->i_mapping, PAGECACHE_TAG_DIRTY))
+ return 0;
+
+ if (eofb) {
+ if (eofb->eof_flags & XFS_EOF_FLAGS_UNION)
+ match = xfs_inode_match_id_union(ip, eofb);
+ else
+ match = xfs_inode_match_id(ip, eofb);
+ if (!match)
+ return 0;
+
+ /* skip the inode if the file size is too small */
+ if (eofb->eof_flags & XFS_EOF_FLAGS_MINFILESIZE &&
+ XFS_ISIZE(ip) < eofb->eof_min_file_size)
+ return 0;
+ }
+
+ /*
+ * If the caller is waiting, return -EAGAIN to keep the background
+ * scanner moving and revisit the inode in a subsequent pass.
+ */
+ if (!xfs_ilock_nowait(ip, XFS_IOLOCK_EXCL)) {
+ if (flags & SYNC_WAIT)
+ ret = -EAGAIN;
+ return ret;
+ }
+ ret = xfs_free_eofblocks(ip);
+ xfs_iunlock(ip, XFS_IOLOCK_EXCL);
+
+ return ret;
+}
+
+static int
+__xfs_icache_free_eofblocks(
+ struct xfs_mount *mp,
+ struct xfs_eofblocks *eofb,
+ int (*execute)(struct xfs_inode *ip, int flags,
+ void *args),
+ int tag)
+{
+ int flags = SYNC_TRYLOCK;
+
+ if (eofb && (eofb->eof_flags & XFS_EOF_FLAGS_SYNC))
+ flags = SYNC_WAIT;
+
+ return xfs_inode_ag_iterator_tag(mp, execute, flags,
+ eofb, tag);
+}
+
+int
+xfs_icache_free_eofblocks(
+ struct xfs_mount *mp,
+ struct xfs_eofblocks *eofb)
+{
+ return __xfs_icache_free_eofblocks(mp, eofb, xfs_inode_free_eofblocks,
+ XFS_ICI_EOFBLOCKS_TAG);
+}
+
+/*
+ * Run eofblocks scans on the quotas applicable to the inode. For inodes with
+ * multiple quotas, we don't know exactly which quota caused an allocation
+ * failure. We make a best effort by including each quota under low free space
+ * conditions (less than 1% free space) in the scan.
+ */
+static int
+__xfs_inode_free_quota_eofblocks(
+ struct xfs_inode *ip,
+ int (*execute)(struct xfs_mount *mp,
+ struct xfs_eofblocks *eofb))
+{
+ int scan = 0;
+ struct xfs_eofblocks eofb = {0};
+ struct xfs_dquot *dq;
+
+ /*
+ * Run a sync scan to increase effectiveness and use the union filter to
+ * cover all applicable quotas in a single scan.
+ */
+ eofb.eof_flags = XFS_EOF_FLAGS_UNION|XFS_EOF_FLAGS_SYNC;
+
+ if (XFS_IS_UQUOTA_ENFORCED(ip->i_mount)) {
+ dq = xfs_inode_dquot(ip, XFS_DQ_USER);
+ if (dq && xfs_dquot_lowsp(dq)) {
+ eofb.eof_uid = VFS_I(ip)->i_uid;
+ eofb.eof_flags |= XFS_EOF_FLAGS_UID;
+ scan = 1;
+ }
+ }
+
+ if (XFS_IS_GQUOTA_ENFORCED(ip->i_mount)) {
+ dq = xfs_inode_dquot(ip, XFS_DQ_GROUP);
+ if (dq && xfs_dquot_lowsp(dq)) {
+ eofb.eof_gid = VFS_I(ip)->i_gid;
+ eofb.eof_flags |= XFS_EOF_FLAGS_GID;
+ scan = 1;
+ }
+ }
+
+ if (scan)
+ execute(ip->i_mount, &eofb);
+
+ return scan;
+}
+
+int
+xfs_inode_free_quota_eofblocks(
+ struct xfs_inode *ip)
+{
+ return __xfs_inode_free_quota_eofblocks(ip, xfs_icache_free_eofblocks);
+}
+
+static inline unsigned long
+xfs_iflag_for_tag(
+ int tag)
+{
+ switch (tag) {
+ case XFS_ICI_EOFBLOCKS_TAG:
+ return XFS_IEOFBLOCKS;
+ case XFS_ICI_COWBLOCKS_TAG:
+ return XFS_ICOWBLOCKS;
+ default:
+ ASSERT(0);
+ return 0;
+ }
+}
+
+static void
+__xfs_inode_set_blocks_tag(
+ xfs_inode_t *ip,
+ void (*execute)(struct xfs_mount *mp),
+ void (*set_tp)(struct xfs_mount *mp, xfs_agnumber_t agno,
+ int error, unsigned long caller_ip),
+ int tag)
+{
+ struct xfs_mount *mp = ip->i_mount;
+ struct xfs_perag *pag;
+ int tagged;
+
+ /*
+ * Don't bother locking the AG and looking up in the radix trees
+ * if we already know that we have the tag set.
+ */
+ if (ip->i_flags & xfs_iflag_for_tag(tag))
+ return;
+ spin_lock(&ip->i_flags_lock);
+ ip->i_flags |= xfs_iflag_for_tag(tag);
+ spin_unlock(&ip->i_flags_lock);
+
+ pag = xfs_perag_get(mp, XFS_INO_TO_AGNO(mp, ip->i_ino));
+ spin_lock(&pag->pag_ici_lock);
+
+ tagged = radix_tree_tagged(&pag->pag_ici_root, tag);
+ radix_tree_tag_set(&pag->pag_ici_root,
+ XFS_INO_TO_AGINO(ip->i_mount, ip->i_ino), tag);
+ if (!tagged) {
+ /* propagate the eofblocks tag up into the perag radix tree */
+ spin_lock(&ip->i_mount->m_perag_lock);
+ radix_tree_tag_set(&ip->i_mount->m_perag_tree,
+ XFS_INO_TO_AGNO(ip->i_mount, ip->i_ino),
+ tag);
+ spin_unlock(&ip->i_mount->m_perag_lock);
+
+ /* kick off background trimming */
+ execute(ip->i_mount);
+
+ set_tp(ip->i_mount, pag->pag_agno, -1, _RET_IP_);
+ }
+
+ spin_unlock(&pag->pag_ici_lock);
+ xfs_perag_put(pag);
+}
+
+void
+xfs_inode_set_eofblocks_tag(
+ xfs_inode_t *ip)
+{
+ trace_xfs_inode_set_eofblocks_tag(ip);
+ return __xfs_inode_set_blocks_tag(ip, xfs_queue_eofblocks,
+ trace_xfs_perag_set_eofblocks,
+ XFS_ICI_EOFBLOCKS_TAG);
+}
+
+static void
+__xfs_inode_clear_blocks_tag(
+ xfs_inode_t *ip,
+ void (*clear_tp)(struct xfs_mount *mp, xfs_agnumber_t agno,
+ int error, unsigned long caller_ip),
+ int tag)
+{
+ struct xfs_mount *mp = ip->i_mount;
+ struct xfs_perag *pag;
+
+ spin_lock(&ip->i_flags_lock);
+ ip->i_flags &= ~xfs_iflag_for_tag(tag);
+ spin_unlock(&ip->i_flags_lock);
+
+ pag = xfs_perag_get(mp, XFS_INO_TO_AGNO(mp, ip->i_ino));
+ spin_lock(&pag->pag_ici_lock);
+
+ radix_tree_tag_clear(&pag->pag_ici_root,
+ XFS_INO_TO_AGINO(ip->i_mount, ip->i_ino), tag);
+ if (!radix_tree_tagged(&pag->pag_ici_root, tag)) {
+ /* clear the eofblocks tag from the perag radix tree */
+ spin_lock(&ip->i_mount->m_perag_lock);
+ radix_tree_tag_clear(&ip->i_mount->m_perag_tree,
+ XFS_INO_TO_AGNO(ip->i_mount, ip->i_ino),
+ tag);
+ spin_unlock(&ip->i_mount->m_perag_lock);
+ clear_tp(ip->i_mount, pag->pag_agno, -1, _RET_IP_);
+ }
+
+ spin_unlock(&pag->pag_ici_lock);
+ xfs_perag_put(pag);
+}
+
+void
+xfs_inode_clear_eofblocks_tag(
+ xfs_inode_t *ip)
+{
+ trace_xfs_inode_clear_eofblocks_tag(ip);
+ return __xfs_inode_clear_blocks_tag(ip,
+ trace_xfs_perag_clear_eofblocks, XFS_ICI_EOFBLOCKS_TAG);
+}
+
+/*
+ * Set ourselves up to free CoW blocks from this file. If it's already clean
+ * then we can bail out quickly, but otherwise we must back off if the file
+ * is undergoing some kind of write.
+ */
+static bool
+xfs_prep_free_cowblocks(
+ struct xfs_inode *ip)
+{
+ /*
+ * Just clear the tag if we have an empty cow fork or none at all. It's
+ * possible the inode was fully unshared since it was originally tagged.
+ */
+ if (!xfs_inode_has_cow_data(ip)) {
+ trace_xfs_inode_free_cowblocks_invalid(ip);
+ xfs_inode_clear_cowblocks_tag(ip);
+ return false;
+ }
+
+ /*
+ * If the mapping is dirty or under writeback we cannot touch the
+ * CoW fork. Leave it alone if we're in the midst of a directio.
+ */
+ if ((VFS_I(ip)->i_state & I_DIRTY_PAGES) ||
+ mapping_tagged(VFS_I(ip)->i_mapping, PAGECACHE_TAG_DIRTY) ||
+ mapping_tagged(VFS_I(ip)->i_mapping, PAGECACHE_TAG_WRITEBACK) ||
+ atomic_read(&VFS_I(ip)->i_dio_count))
+ return false;
+
+ return true;
+}
+
+/*
+ * Automatic CoW Reservation Freeing
+ *
+ * These functions automatically garbage collect leftover CoW reservations
+ * that were made on behalf of a cowextsize hint when we start to run out
+ * of quota or when the reservations sit around for too long. If the file
+ * has dirty pages or is undergoing writeback, its CoW reservations will
+ * be retained.
+ *
+ * The actual garbage collection piggybacks off the same code that runs
+ * the speculative EOF preallocation garbage collector.
+ */
+STATIC int
+xfs_inode_free_cowblocks(
+ struct xfs_inode *ip,
+ int flags,
+ void *args)
+{
+ struct xfs_eofblocks *eofb = args;
+ int match;
+ int ret = 0;
+
+ if (!xfs_prep_free_cowblocks(ip))
+ return 0;
+
+ if (eofb) {
+ if (eofb->eof_flags & XFS_EOF_FLAGS_UNION)
+ match = xfs_inode_match_id_union(ip, eofb);
+ else
+ match = xfs_inode_match_id(ip, eofb);
+ if (!match)
+ return 0;
+
+ /* skip the inode if the file size is too small */
+ if (eofb->eof_flags & XFS_EOF_FLAGS_MINFILESIZE &&
+ XFS_ISIZE(ip) < eofb->eof_min_file_size)
+ return 0;
+ }
+
+ /* Free the CoW blocks */
+ xfs_ilock(ip, XFS_IOLOCK_EXCL);
+ xfs_ilock(ip, XFS_MMAPLOCK_EXCL);
+
+ /*
+ * Check again, nobody else should be able to dirty blocks or change
+ * the reflink iflag now that we have the first two locks held.
+ */
+ if (xfs_prep_free_cowblocks(ip))
+ ret = xfs_reflink_cancel_cow_range(ip, 0, NULLFILEOFF, false);
+
+ xfs_iunlock(ip, XFS_MMAPLOCK_EXCL);
+ xfs_iunlock(ip, XFS_IOLOCK_EXCL);
+
+ return ret;
+}
+
+int
+xfs_icache_free_cowblocks(
+ struct xfs_mount *mp,
+ struct xfs_eofblocks *eofb)
+{
+ return __xfs_icache_free_eofblocks(mp, eofb, xfs_inode_free_cowblocks,
+ XFS_ICI_COWBLOCKS_TAG);
+}
+
+int
+xfs_inode_free_quota_cowblocks(
+ struct xfs_inode *ip)
+{
+ return __xfs_inode_free_quota_eofblocks(ip, xfs_icache_free_cowblocks);
+}
+
+void
+xfs_inode_set_cowblocks_tag(
+ xfs_inode_t *ip)
+{
+ trace_xfs_inode_set_cowblocks_tag(ip);
+ return __xfs_inode_set_blocks_tag(ip, xfs_queue_cowblocks,
+ trace_xfs_perag_set_cowblocks,
+ XFS_ICI_COWBLOCKS_TAG);
+}
+
+void
+xfs_inode_clear_cowblocks_tag(
+ xfs_inode_t *ip)
+{
+ trace_xfs_inode_clear_cowblocks_tag(ip);
+ return __xfs_inode_clear_blocks_tag(ip,
+ trace_xfs_perag_clear_cowblocks, XFS_ICI_COWBLOCKS_TAG);
+}
+
+/* Disable post-EOF and CoW block auto-reclamation. */
+void
+xfs_icache_disable_reclaim(
+ struct xfs_mount *mp)
+{
+ cancel_delayed_work_sync(&mp->m_eofblocks_work);
+ cancel_delayed_work_sync(&mp->m_cowblocks_work);
+}
+
+/* Enable post-EOF and CoW block auto-reclamation. */
+void
+xfs_icache_enable_reclaim(
+ struct xfs_mount *mp)
+{
+ xfs_queue_eofblocks(mp);
+ xfs_queue_cowblocks(mp);
+}