diff options
Diffstat (limited to 'fs/xfs/linux-2.6/xfs_sync.c')
| -rw-r--r-- | fs/xfs/linux-2.6/xfs_sync.c | 1132 |
1 files changed, 0 insertions, 1132 deletions
diff --git a/fs/xfs/linux-2.6/xfs_sync.c b/fs/xfs/linux-2.6/xfs_sync.c deleted file mode 100644 index 2f277a0..0000000 --- a/fs/xfs/linux-2.6/xfs_sync.c +++ /dev/null @@ -1,1132 +0,0 @@ -/* - * Copyright (c) 2000-2005 Silicon Graphics, Inc. - * All Rights Reserved. - * - * This program is free software; you can redistribute it and/or - * modify it under the terms of the GNU General Public License as - * published by the Free Software Foundation. - * - * This program is distributed in the hope that it would be useful, - * but WITHOUT ANY WARRANTY; without even the implied warranty of - * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the - * GNU General Public License for more details. - * - * You should have received a copy of the GNU General Public License - * along with this program; if not, write the Free Software Foundation, - * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA - */ -#include "xfs.h" -#include "xfs_fs.h" -#include "xfs_types.h" -#include "xfs_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; - - } 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)) - goto out_wait; - - if (!xfs_ilock_nowait(ip, XFS_IOLOCK_SHARED)) { - if (flags & SYNC_TRYLOCK) - goto out_wait; - 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); - - out_wait: - if (flags & SYNC_WAIT) - xfs_ioend_wait(ip); - 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; - - /* - * 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); - - return xfs_bwrite(mp, bp); -} - -int -xfs_log_dirty_inode( - struct xfs_inode *ip, - struct xfs_perag *pag, - int flags) -{ - struct xfs_mount *mp = ip->i_mount; - struct xfs_trans *tp; - int error; - - if (!ip->i_update_core) - return 0; - - tp = xfs_trans_alloc(mp, XFS_TRANS_FSYNC_TS); - error = xfs_trans_reserve(tp, 0, XFS_FSYNC_TS_LOG_RES(mp), 0, 0, 0); - if (error) { - xfs_trans_cancel(tp, 0); - return error; - } - - xfs_ilock(ip, XFS_ILOCK_EXCL); - xfs_trans_ijoin_ref(tp, ip, XFS_ILOCK_EXCL); - xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE); - return xfs_trans_commit(tp, 0); -} - -/* - * 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; - - /* push non-blocking */ - xfs_sync_data(mp, 0); - xfs_qm_sync(mp, SYNC_TRYLOCK); - - /* push and block till complete */ - xfs_sync_data(mp, SYNC_WAIT); - - /* - * Log all pending size and timestamp updates. The vfs writeback - * code is supposed to do this, but due to its overagressive - * livelock detection it will skip inodes where appending writes - * were written out in the first non-blocking sync phase if their - * completion took long enough that it happened after taking the - * timestamp for the cut-off in the blocking phase. - */ - xfs_inode_ag_iterator(mp, xfs_log_dirty_inode, 0); - - xfs_qm_sync(mp, SYNC_WAIT); - - /* 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_bflush(mp->m_rtdev_targp); - - 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, 1); - 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); - error = xfs_qm_sync(mp, SYNC_TRYLOCK); - - /* 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; - - /* - * do some unlocked checks first to avoid unnecessary lock traffic. - * The first is a flush lock check, the second is a already in reclaim - * check. Only do these checks if we are not going to block on locks. - */ - if ((flags & SYNC_TRYLOCK) && - (!ip->i_flush.done || __xfs_iflags_test(ip, 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. We get - * both the ilock and the iolock because the code may need to drop the - * ilock one but will still hold the iolock. - */ - xfs_ilock(ip, XFS_ILOCK_EXCL | XFS_IOLOCK_EXCL); - xfs_qm_dqdetach(ip); - xfs_iunlock(ip, XFS_ILOCK_EXCL | XFS_IOLOCK_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; - - } 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 (trylock && skipped && *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); -} - -/* - * Inode cache shrinker. - * - * When called we make sure that there is a background (fast) inode reclaim in - * progress, while we will throttle the speed of reclaim via doiing 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. - */ -static int -xfs_reclaim_inode_shrink( - struct shrinker *shrink, - struct shrink_control *sc) -{ - struct xfs_mount *mp; - struct xfs_perag *pag; - xfs_agnumber_t ag; - int reclaimable; - int nr_to_scan = sc->nr_to_scan; - gfp_t gfp_mask = sc->gfp_mask; - - mp = container_of(shrink, struct xfs_mount, m_inode_shrink); - if (nr_to_scan) { - /* kick background reclaimer and push the AIL */ - xfs_syncd_queue_reclaim(mp); - xfs_ail_push_all(mp->m_ail); - - if (!(gfp_mask & __GFP_FS)) - return -1; - - xfs_reclaim_inodes_ag(mp, SYNC_TRYLOCK | SYNC_WAIT, - &nr_to_scan); - /* terminate if we don't exhaust the scan */ - if (nr_to_scan > 0) - return -1; - } - - reclaimable = 0; - ag = 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; -} - -void -xfs_inode_shrinker_register( - struct xfs_mount *mp) -{ - mp->m_inode_shrink.shrink = xfs_reclaim_inode_shrink; - mp->m_inode_shrink.seeks = DEFAULT_SEEKS; - register_shrinker(&mp->m_inode_shrink); -} - -void -xfs_inode_shrinker_unregister( - struct xfs_mount *mp) -{ - unregister_shrinker(&mp->m_inode_shrink); -} |