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-rw-r--r--fs/xfs/xfs_icache.c1341
1 files changed, 1341 insertions, 0 deletions
diff --git a/fs/xfs/xfs_icache.c b/fs/xfs/xfs_icache.c
new file mode 100644
index 00000000000..96e344e3e92
--- /dev/null
+++ b/fs/xfs/xfs_icache.c
@@ -0,0 +1,1341 @@
+/*
+ * Copyright (c) 2000-2005 Silicon Graphics, Inc.
+ * All Rights Reserved.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it would be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+#include "xfs.h"
+#include "xfs_fs.h"
+#include "xfs_types.h"
+#include "xfs_log.h"
+#include "xfs_log_priv.h"
+#include "xfs_inum.h"
+#include "xfs_trans.h"
+#include "xfs_trans_priv.h"
+#include "xfs_sb.h"
+#include "xfs_ag.h"
+#include "xfs_mount.h"
+#include "xfs_bmap_btree.h"
+#include "xfs_inode.h"
+#include "xfs_dinode.h"
+#include "xfs_error.h"
+#include "xfs_filestream.h"
+#include "xfs_vnodeops.h"
+#include "xfs_inode_item.h"
+#include "xfs_quota.h"
+#include "xfs_trace.h"
+#include "xfs_fsops.h"
+#include "xfs_icache.h"
+
+#include <linux/kthread.h>
+#include <linux/freezer.h>
+
+STATIC void __xfs_inode_clear_reclaim_tag(struct xfs_mount *mp,
+ struct xfs_perag *pag, struct xfs_inode *ip);
+
+/*
+ * Allocate and initialise an xfs_inode.
+ */
+STATIC 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;
+ }
+
+ ASSERT(atomic_read(&ip->i_pincount) == 0);
+ ASSERT(!spin_is_locked(&ip->i_flags_lock));
+ ASSERT(!xfs_isiflocked(ip));
+ ASSERT(ip->i_ino == 0);
+
+ mrlock_init(&ip->i_iolock, MRLOCK_BARRIER, "xfsio", ip->i_ino);
+
+ /* 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;
+ memset(&ip->i_df, 0, sizeof(xfs_ifork_t));
+ ip->i_flags = 0;
+ ip->i_delayed_blks = 0;
+ memset(&ip->i_d, 0, sizeof(xfs_icdinode_t));
+
+ 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);
+
+ kmem_zone_free(xfs_inode_zone, ip);
+}
+
+STATIC void
+xfs_inode_free(
+ struct xfs_inode *ip)
+{
+ switch (ip->i_d.di_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_itemp) {
+ ASSERT(!(ip->i_itemp->ili_item.li_flags & XFS_LI_IN_AIL));
+ xfs_inode_item_destroy(ip);
+ ip->i_itemp = NULL;
+ }
+
+ /* asserts to verify all state is correct here */
+ ASSERT(atomic_read(&ip->i_pincount) == 0);
+ ASSERT(!spin_is_locked(&ip->i_flags_lock));
+ 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);
+
+ call_rcu(&VFS_I(ip)->i_rcu, xfs_inode_free_callback);
+}
+
+/*
+ * 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(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(xs_ig_frecycle);
+ error = EAGAIN;
+ goto out_error;
+ }
+
+ /*
+ * If lookup is racing with unlink return an error immediately.
+ */
+ if (ip->i_d.di_mode == 0 && !(flags & XFS_IGET_CREATE)) {
+ error = ENOENT;
+ 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);
+
+ /*
+ * 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 = -inode_init_always(mp->m_super, inode);
+ if (error) {
+ /*
+ * 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);
+
+ ip->i_flags &= ~(XFS_INEW | XFS_IRECLAIM);
+ 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(mp, pag, ip);
+ inode->i_state = I_NEW;
+
+ ASSERT(!rwsem_is_locked(&ip->i_iolock.mr_lock));
+ mrlock_init(&ip->i_iolock, MRLOCK_BARRIER, "xfsio", ip->i_ino);
+
+ 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);
+
+ xfs_iflags_clear(ip, XFS_ISTALE | XFS_IDONTCACHE);
+ XFS_STATS_INC(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;
+
+ trace_xfs_iget_miss(ip);
+
+ if ((ip->i_d.di_mode == 0) && !(flags & XFS_IGET_CREATE)) {
+ error = ENOENT;
+ 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 = ip->i_gdquot = 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(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;
+
+ /* 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();
+ XFS_STATS_INC(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 set ops(&unlock)
+ * now. If it's a new inode being created, xfs_ialloc will handle it.
+ */
+ if (xfs_iflags_test(ip, XFS_INEW) && ip->i_d.di_mode != 0)
+ xfs_setup_inode(ip);
+ return 0;
+
+out_error_or_again:
+ if (error == EAGAIN) {
+ delay(1);
+ goto again;
+ }
+ xfs_perag_put(pag);
+ return error;
+}
+
+/*
+ * 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)
+{
+ struct inode *inode = VFS_I(ip);
+
+ 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 (__xfs_iflags_test(ip, XFS_INEW | 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;
+
+ if (is_bad_inode(inode)) {
+ IRELE(ip);
+ 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,
+ struct xfs_perag *pag, int flags,
+ void *args),
+ int flags,
+ void *args,
+ int tag)
+{
+ 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))
+ 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 = execute(batch[i], pag, flags, args);
+ 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 'background_prealloc_discard_period' tunable (5m by default).
+ */
+STATIC 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);
+}
+
+int
+xfs_inode_ag_iterator(
+ struct xfs_mount *mp,
+ int (*execute)(struct xfs_inode *ip,
+ struct xfs_perag *pag, int flags,
+ void *args),
+ int flags,
+ void *args)
+{
+ 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);
+ xfs_perag_put(pag);
+ if (error) {
+ last_error = error;
+ if (error == EFSCORRUPTED)
+ break;
+ }
+ }
+ return XFS_ERROR(last_error);
+}
+
+int
+xfs_inode_ag_iterator_tag(
+ struct xfs_mount *mp,
+ int (*execute)(struct xfs_inode *ip,
+ struct xfs_perag *pag, 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);
+ xfs_perag_put(pag);
+ if (error) {
+ last_error = error;
+ if (error == EFSCORRUPTED)
+ break;
+ }
+ }
+ return XFS_ERROR(last_error);
+}
+
+/*
+ * 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_inode_set_reclaim_tag(
+ struct xfs_perag *pag,
+ struct xfs_inode *ip)
+{
+ radix_tree_tag_set(&pag->pag_ici_root,
+ XFS_INO_TO_AGINO(ip->i_mount, ip->i_ino),
+ XFS_ICI_RECLAIM_TAG);
+
+ if (!pag->pag_ici_reclaimable) {
+ /* propagate the reclaim 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),
+ XFS_ICI_RECLAIM_TAG);
+ spin_unlock(&ip->i_mount->m_perag_lock);
+
+ /* schedule periodic background inode reclaim */
+ xfs_reclaim_work_queue(ip->i_mount);
+
+ trace_xfs_perag_set_reclaim(ip->i_mount, pag->pag_agno,
+ -1, _RET_IP_);
+ }
+ pag->pag_ici_reclaimable++;
+}
+
+/*
+ * 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(
+ xfs_inode_t *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);
+ __xfs_inode_set_reclaim_tag(pag, ip);
+ __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(
+ xfs_perag_t *pag,
+ xfs_inode_t *ip)
+{
+ pag->pag_ici_reclaimable--;
+ if (!pag->pag_ici_reclaimable) {
+ /* clear the reclaim 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),
+ XFS_ICI_RECLAIM_TAG);
+ spin_unlock(&ip->i_mount->m_perag_lock);
+ trace_xfs_perag_clear_reclaim(ip->i_mount, pag->pag_agno,
+ -1, _RET_IP_);
+ }
+}
+
+STATIC void
+__xfs_inode_clear_reclaim_tag(
+ xfs_mount_t *mp,
+ xfs_perag_t *pag,
+ xfs_inode_t *ip)
+{
+ radix_tree_tag_clear(&pag->pag_ici_root,
+ XFS_INO_TO_AGINO(mp, ip->i_ino), XFS_ICI_RECLAIM_TAG);
+ __xfs_inode_clear_reclaim(pag, ip);
+}
+
+/*
+ * 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;
+ 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 (is_bad_inode(VFS_I(ip)))
+ goto reclaim;
+ if (XFS_FORCED_SHUTDOWN(ip->i_mount)) {
+ xfs_iunpin_wait(ip);
+ 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))
+ goto reclaim;
+ if (xfs_inode_clean(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);
+ }
+
+ xfs_iflock(ip);
+reclaim:
+ xfs_ifunlock(ip);
+ xfs_iunlock(ip, XFS_ILOCK_EXCL);
+
+ XFS_STATS_INC(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, ip->i_ino)))
+ ASSERT(0);
+ __xfs_inode_clear_reclaim(pag, ip);
+ 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 XFS_ERROR(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.
+ */
+void
+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);
+
+ 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 &&
+ ip->i_d.di_uid != eofb->eof_uid)
+ return 0;
+
+ if (eofb->eof_flags & XFS_EOF_FLAGS_GID &&
+ ip->i_d.di_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;
+}
+
+STATIC int
+xfs_inode_free_eofblocks(
+ struct xfs_inode *ip,
+ struct xfs_perag *pag,
+ int flags,
+ void *args)
+{
+ int ret;
+ struct xfs_eofblocks *eofb = args;
+
+ 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 (!xfs_inode_match_id(ip, eofb))
+ 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;
+ }
+
+ ret = xfs_free_eofblocks(ip->i_mount, ip, true);
+
+ /* don't revisit the inode if we're not waiting */
+ if (ret == EAGAIN && !(flags & SYNC_WAIT))
+ ret = 0;
+
+ return ret;
+}
+
+int
+xfs_icache_free_eofblocks(
+ struct xfs_mount *mp,
+ struct xfs_eofblocks *eofb)
+{
+ int flags = SYNC_TRYLOCK;
+
+ if (eofb && (eofb->eof_flags & XFS_EOF_FLAGS_SYNC))
+ flags = SYNC_WAIT;
+
+ return xfs_inode_ag_iterator_tag(mp, xfs_inode_free_eofblocks, flags,
+ eofb, XFS_ICI_EOFBLOCKS_TAG);
+}
+
+void
+xfs_inode_set_eofblocks_tag(
+ xfs_inode_t *ip)
+{
+ struct xfs_mount *mp = ip->i_mount;
+ struct xfs_perag *pag;
+ int tagged;
+
+ pag = xfs_perag_get(mp, XFS_INO_TO_AGNO(mp, ip->i_ino));
+ spin_lock(&pag->pag_ici_lock);
+ trace_xfs_inode_set_eofblocks_tag(ip);
+
+ tagged = radix_tree_tagged(&pag->pag_ici_root,
+ XFS_ICI_EOFBLOCKS_TAG);
+ radix_tree_tag_set(&pag->pag_ici_root,
+ XFS_INO_TO_AGINO(ip->i_mount, ip->i_ino),
+ XFS_ICI_EOFBLOCKS_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),
+ XFS_ICI_EOFBLOCKS_TAG);
+ spin_unlock(&ip->i_mount->m_perag_lock);
+
+ /* kick off background trimming */
+ xfs_queue_eofblocks(ip->i_mount);
+
+ trace_xfs_perag_set_eofblocks(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)
+{
+ 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);
+ trace_xfs_inode_clear_eofblocks_tag(ip);
+
+ radix_tree_tag_clear(&pag->pag_ici_root,
+ XFS_INO_TO_AGINO(ip->i_mount, ip->i_ino),
+ XFS_ICI_EOFBLOCKS_TAG);
+ if (!radix_tree_tagged(&pag->pag_ici_root, XFS_ICI_EOFBLOCKS_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),
+ XFS_ICI_EOFBLOCKS_TAG);
+ spin_unlock(&ip->i_mount->m_perag_lock);
+ trace_xfs_perag_clear_eofblocks(ip->i_mount, pag->pag_agno,
+ -1, _RET_IP_);
+ }
+
+ spin_unlock(&pag->pag_ici_lock);
+ xfs_perag_put(pag);
+}
+