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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_bit.h" #include "xfs_log.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 <linux/kthread.h> #include <linux/freezer.h> struct workqueue_struct *xfs_syncd_wq; /* sync workqueue */ /* * 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), int flags) { uint32_t first_index; int last_error = 0; int skipped; int done; int nr_found; restart: done = 0; skipped = 0; first_index = 0; nr_found = 0; do { struct xfs_inode *batch[XFS_LOOKUP_BATCH]; int error = 0; int i; rcu_read_lock(); nr_found = radix_tree_gang_lookup(&pag->pag_ici_root, (void **)batch, first_index, XFS_LOOKUP_BATCH); 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); 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; } int xfs_inode_ag_iterator( struct xfs_mount *mp, int (*execute)(struct xfs_inode *ip, struct xfs_perag *pag, int flags), int flags) { struct xfs_perag *pag; int error = 0; int last_error = 0; xfs_agnumber_t ag; ag = 0; while ((pag = xfs_perag_get(mp, ag))) { ag = pag->pag_agno + 1; error = xfs_inode_ag_walk(mp, pag, execute, flags); xfs_perag_put(pag); if (error) { last_error = error; if (error == EFSCORRUPTED) break; } } return XFS_ERROR(last_error); } STATIC int xfs_sync_inode_data( struct xfs_inode *ip, struct xfs_perag *pag, int flags) { struct inode *inode = VFS_I(ip); struct address_space *mapping = inode->i_mapping; int error = 0; if (!mapping_tagged(mapping, PAGECACHE_TAG_DIRTY)) return 0; if (!xfs_ilock_nowait(ip, XFS_IOLOCK_SHARED)) { if (flags & SYNC_TRYLOCK) return 0; xfs_ilock(ip, XFS_IOLOCK_SHARED); } error = xfs_flush_pages(ip, 0, -1, (flags & SYNC_WAIT) ? 0 : XBF_ASYNC, FI_NONE); xfs_iunlock(ip, XFS_IOLOCK_SHARED); return error; } STATIC int xfs_sync_inode_attr( struct xfs_inode *ip, struct xfs_perag *pag, int flags) { int error = 0; xfs_ilock(ip, XFS_ILOCK_SHARED); if (xfs_inode_clean(ip)) goto out_unlock; if (!xfs_iflock_nowait(ip)) { if (!(flags & SYNC_WAIT)) goto out_unlock; xfs_iflock(ip); } if (xfs_inode_clean(ip)) { xfs_ifunlock(ip); goto out_unlock; } error = xfs_iflush(ip, flags); /* * We don't want to try again on non-blocking flushes that can't run * again immediately. If an inode really must be written, then that's * what the SYNC_WAIT flag is for. */ if (error == EAGAIN) { ASSERT(!(flags & SYNC_WAIT)); error = 0; } out_unlock: xfs_iunlock(ip, XFS_ILOCK_SHARED); return error; } /* * Write out pagecache data for the whole filesystem. */ STATIC int xfs_sync_data( struct xfs_mount *mp, int flags) { int error; ASSERT((flags & ~(SYNC_TRYLOCK|SYNC_WAIT)) == 0); error = xfs_inode_ag_iterator(mp, xfs_sync_inode_data, flags); if (error) return XFS_ERROR(error); xfs_log_force(mp, (flags & SYNC_WAIT) ? XFS_LOG_SYNC : 0); return 0; } /* * Write out inode metadata (attributes) for the whole filesystem. */ STATIC int xfs_sync_attr( struct xfs_mount *mp, int flags) { ASSERT((flags & ~SYNC_WAIT) == 0); return xfs_inode_ag_iterator(mp, xfs_sync_inode_attr, flags); } STATIC int xfs_sync_fsdata( struct xfs_mount *mp) { struct xfs_buf *bp; int error; /* * If the buffer is pinned then push on the log so we won't get stuck * waiting in the write for someone, maybe ourselves, to flush the log. * * Even though we just pushed the log above, we did not have the * superblock buffer locked at that point so it can become pinned in * between there and here. */ bp = xfs_getsb(mp, 0); if (xfs_buf_ispinned(bp)) xfs_log_force(mp, 0); error = xfs_bwrite(bp); xfs_buf_relse(bp); return error; } /* * When remounting a filesystem read-only or freezing the filesystem, we have * two phases to execute. This first phase is syncing the data before we * quiesce the filesystem, and the second is flushing all the inodes out after * we've waited for all the transactions created by the first phase to * complete. The second phase ensures that the inodes are written to their * location on disk rather than just existing in transactions in the log. This * means after a quiesce there is no log replay required to write the inodes to * disk (this is the main difference between a sync and a quiesce). */ /* * First stage of freeze - no writers will make progress now we are here, * so we flush delwri and delalloc buffers here, then wait for all I/O to * complete. Data is frozen at that point. Metadata is not frozen, * transactions can still occur here so don't bother flushing the buftarg * because it'll just get dirty again. */ int xfs_quiesce_data( struct xfs_mount *mp) { int error, error2 = 0; /* force out the log */ xfs_log_force(mp, XFS_LOG_SYNC); /* write superblock and hoover up shutdown errors */ error = xfs_sync_fsdata(mp); /* make sure all delwri buffers are written out */ xfs_flush_buftarg(mp->m_ddev_targp, 1); /* mark the log as covered if needed */ if (xfs_log_need_covered(mp)) error2 = xfs_fs_log_dummy(mp); /* flush data-only devices */ if (mp->m_rtdev_targp) xfs_flush_buftarg(mp->m_rtdev_targp, 1); return error ? error : error2; } STATIC void xfs_quiesce_fs( struct xfs_mount *mp) { int count = 0, pincount; xfs_reclaim_inodes(mp, 0); xfs_flush_buftarg(mp->m_ddev_targp, 0); /* * This loop must run at least twice. The first instance of the loop * will flush most meta data but that will generate more meta data * (typically directory updates). Which then must be flushed and * logged before we can write the unmount record. We also so sync * reclaim of inodes to catch any that the above delwri flush skipped. */ do { xfs_reclaim_inodes(mp, SYNC_WAIT); xfs_sync_attr(mp, SYNC_WAIT); pincount = xfs_flush_buftarg(mp->m_ddev_targp, 1); if (!pincount) { delay(50); count++; } } while (count < 2); } /* * Second stage of a quiesce. The data is already synced, now we have to take * care of the metadata. New transactions are already blocked, so we need to * wait for any remaining transactions to drain out before proceeding. */ void xfs_quiesce_attr( struct xfs_mount *mp) { int error = 0; /* wait for all modifications to complete */ while (atomic_read(&mp->m_active_trans) > 0) delay(100); /* flush inodes and push all remaining buffers out to disk */ xfs_quiesce_fs(mp); /* * Just warn here till VFS can correctly support * read-only remount without racing. */ WARN_ON(atomic_read(&mp->m_active_trans) != 0); /* Push the superblock and write an unmount record */ error = xfs_log_sbcount(mp); if (error) xfs_warn(mp, "xfs_attr_quiesce: failed to log sb changes. " "Frozen image may not be consistent."); xfs_log_unmount_write(mp); xfs_unmountfs_writesb(mp); } static void xfs_syncd_queue_sync( struct xfs_mount *mp) { queue_delayed_work(xfs_syncd_wq, &mp->m_sync_work, msecs_to_jiffies(xfs_syncd_centisecs * 10)); } /* * Every sync period we need to unpin all items, reclaim inodes and sync * disk quotas. We might need to cover the log to indicate that the * filesystem is idle and not frozen. */ STATIC void xfs_sync_worker( struct work_struct *work) { struct xfs_mount *mp = container_of(to_delayed_work(work), struct xfs_mount, m_sync_work); int error; if (!(mp->m_flags & XFS_MOUNT_RDONLY)) { /* dgc: errors ignored here */ if (mp->m_super->s_frozen == SB_UNFROZEN && xfs_log_need_covered(mp)) error = xfs_fs_log_dummy(mp); else xfs_log_force(mp, 0); /* start pushing all the metadata that is currently dirty */ xfs_ail_push_all(mp->m_ail); } /* queue us up again */ xfs_syncd_queue_sync(mp); } /* * 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 syncd work 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_syncd_queue_reclaim( struct xfs_mount *mp) { /* * We can have inodes enter reclaim after we've shut down the syncd * workqueue during unmount, so don't allow reclaim work to be queued * during unmount. */ if (!(mp->m_super->s_flags & MS_ACTIVE)) return; rcu_read_lock(); if (radix_tree_tagged(&mp->m_perag_tree, XFS_ICI_RECLAIM_TAG)) { queue_delayed_work(xfs_syncd_wq, &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. */ STATIC 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_syncd_queue_reclaim(mp); } /* * Flush delayed allocate data, attempting to free up reserved space * from existing allocations. At this point a new allocation attempt * has failed with ENOSPC and we are in the process of scratching our * heads, looking about for more room. * * Queue a new data flush if there isn't one already in progress and * wait for completion of the flush. This means that we only ever have one * inode flush in progress no matter how many ENOSPC events are occurring and * so will prevent the system from bogging down due to every concurrent * ENOSPC event scanning all the active inodes in the system for writeback. */ void xfs_flush_inodes( struct xfs_inode *ip) { struct xfs_mount *mp = ip->i_mount; queue_work(xfs_syncd_wq, &mp->m_flush_work); flush_work_sync(&mp->m_flush_work); } STATIC void xfs_flush_worker( struct work_struct *work) { struct xfs_mount *mp = container_of(work, struct xfs_mount, m_flush_work); xfs_sync_data(mp, SYNC_TRYLOCK); xfs_sync_data(mp, SYNC_TRYLOCK | SYNC_WAIT); } int xfs_syncd_init( struct xfs_mount *mp) { INIT_WORK(&mp->m_flush_work, xfs_flush_worker); INIT_DELAYED_WORK(&mp->m_sync_work, xfs_sync_worker); INIT_DELAYED_WORK(&mp->m_reclaim_work, xfs_reclaim_worker); xfs_syncd_queue_sync(mp); xfs_syncd_queue_reclaim(mp); return 0; } void xfs_syncd_stop( struct xfs_mount *mp) { cancel_delayed_work_sync(&mp->m_sync_work); cancel_delayed_work_sync(&mp->m_reclaim_work); cancel_work_sync(&mp->m_flush_work); } 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_syncd_queue_reclaim(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_); } } 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, and the return * value of xfs_iflush is not sufficient to get this right. The following table * lists the inode states and the reclaim actions necessary for non-blocking * reclaim: * * * 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, delwri ok 0 requeue * dirty, delwri blocked EAGAIN requeue * dirty, sync flush 0 reclaim * * (*) dgc: I don't think the clean, pinned state is possible but it gets * handled anyway given the order of checks implemented. * * As can be seen from the table, the return value of xfs_iflush() is not * sufficient to correctly decide the reclaim action here. The checks in * xfs_iflush() might look like duplicates, but they are not. * * 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. The clean inode check needs to be done before flushing * the inode delwri otherwise we would loop forever requeuing clean inodes as * we cannot tell apart a successful delwri flush and a clean inode from the * return value of xfs_iflush(). * * Note that because the inode is flushed delayed write by background * writeback, 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 out delayed write inodes first before * trying to reclaim them to minimise the amount of time spent waiting. For * background relaim, we just requeue the inode for the next pass. * * Hence the order of actions after gaining the locks should be: * bad => reclaim * shutdown => unpin and reclaim * pinned, delwri => requeue * pinned, sync => unpin * stale => reclaim * clean => reclaim * dirty, delwri => flush and requeue * dirty, sync => flush, wait and reclaim */ STATIC int xfs_reclaim_inode( struct xfs_inode *ip, struct xfs_perag *pag, int sync_mode) { int error; restart: error = 0; xfs_ilock(ip, XFS_ILOCK_EXCL); if (!xfs_iflock_nowait(ip)) { if (!(sync_mode & SYNC_WAIT)) goto out; /* * If we only have a single dirty inode in a cluster there is * a fair chance that the AIL push may have pushed it into * the buffer, but xfsbufd won't touch it until 30 seconds * from now, and thus we will lock up here. * * Promote the inode buffer to the front of the delwri list * and wake up xfsbufd now. */ xfs_promote_inode(ip); xfs_iflock(ip); } if (is_bad_inode(VFS_I(ip))) goto reclaim; if (XFS_FORCED_SHUTDOWN(ip->i_mount)) { xfs_iunpin_wait(ip); goto reclaim; } if (xfs_ipincount(ip)) { if (!(sync_mode & SYNC_WAIT)) { xfs_ifunlock(ip); goto out; } xfs_iunpin_wait(ip); } if (xfs_iflags_test(ip, XFS_ISTALE)) goto reclaim; if (xfs_inode_clean(ip)) goto reclaim; /* * Now we have an inode that needs flushing. * * We do a nonblocking flush here even if we are doing a SYNC_WAIT * reclaim as we can deadlock with inode cluster removal. * 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_itobp() to get the cluster buffer will 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 on a SYNC_WAIT flush, * 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, SYNC_TRYLOCK | sync_mode); if (sync_mode & SYNC_WAIT) { if (error == EAGAIN) { xfs_iunlock(ip, XFS_ILOCK_EXCL); /* backoff longer than in xfs_ifree_cluster */ delay(2); goto restart; } xfs_iflock(ip); goto reclaim; } /* * When we have to flush an inode but don't have SYNC_WAIT set, we * flush the inode out using a delwri buffer and wait for the next * call into reclaim to find it in a clean state instead of waiting for * it now. We also don't return errors here - if the error is transient * then the next reclaim pass will flush the inode, and if the error * is permanent then the next sync reclaim will reclaim the inode and * pass on the error. */ if (error && error != EAGAIN && !XFS_FORCED_SHUTDOWN(ip->i_mount)) { xfs_warn(ip->i_mount, "inode 0x%llx background reclaim flush failed with %d", (long long)ip->i_ino, error); } 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 xfssyncd 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; 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; } /* * 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. */ 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_syncd_queue_reclaim(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; } |