diff options
Diffstat (limited to 'fs/xfs/xfs_icache.c')
| -rw-r--r-- | fs/xfs/xfs_icache.c | 1327 |
1 files changed, 1327 insertions, 0 deletions
diff --git a/fs/xfs/xfs_icache.c b/fs/xfs/xfs_icache.c new file mode 100644 index 00000000000..c48df5f25b9 --- /dev/null +++ b/fs/xfs/xfs_icache.c @@ -0,0 +1,1327 @@ +/* + * 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_format.h" +#include "xfs_log_format.h" +#include "xfs_trans_resv.h" +#include "xfs_inum.h" +#include "xfs_sb.h" +#include "xfs_ag.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 <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. + */ +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); +} + +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; + } + + /* + * 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); + + /* asserts to verify all state is correct here */ + ASSERT(atomic_read(&ip->i_pincount) == 0); + ASSERT(!xfs_isiflocked(ip)); + + 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 = 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(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; + + /* 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) +{ + 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], 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 'speculative_prealloc_lifetime' 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, 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, 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 (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. + */ +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; +} + +STATIC int +xfs_inode_free_eofblocks( + struct xfs_inode *ip, + 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); +} + |