/* * 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_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 #include 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; } XFS_STATS_INC(mp, vn_active); 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(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); 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)); XFS_STATS_DEC(ip->i_mount, vn_active); 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(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; } /* * 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(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; 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(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(); 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) && ip->i_d.di_mode != 0) xfs_setup_existing_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 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 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(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, 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 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; struct xfs_eofblocks *eofb = args; bool need_iolock = true; int match; ASSERT(!eofb || (eofb && eofb->eof_scan_owner != 0)); 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; /* * A scan owner implies we already hold the iolock. Skip it in * xfs_free_eofblocks() to avoid deadlock. This also eliminates * the possibility of EAGAIN being returned. */ if (eofb->eof_scan_owner == ip->i_ino) need_iolock = false; } ret = xfs_free_eofblocks(ip->i_mount, ip, need_iolock); /* 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); } /* * 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. */ int xfs_inode_free_quota_eofblocks( struct xfs_inode *ip) { int scan = 0; struct xfs_eofblocks eofb = {0}; struct xfs_dquot *dq; ASSERT(xfs_isilocked(ip, XFS_IOLOCK_EXCL)); /* * Set the scan owner to avoid a potential livelock. Otherwise, the scan * can repeatedly trylock on the inode we're currently processing. We * run a sync scan to increase effectiveness and use the union filter to * cover all applicable quotas in a single scan. */ eofb.eof_scan_owner = ip->i_ino; 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) xfs_icache_free_eofblocks(ip->i_mount, &eofb); return scan; } 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); }