diff options
Diffstat (limited to 'fs/xfs/linux-2.6/xfs_sync.c')
| -rw-r--r-- | fs/xfs/linux-2.6/xfs_sync.c | 105 |
1 files changed, 76 insertions, 29 deletions
diff --git a/fs/xfs/linux-2.6/xfs_sync.c b/fs/xfs/linux-2.6/xfs_sync.c index 525260c7617f..a9f6d20aff41 100644 --- a/fs/xfs/linux-2.6/xfs_sync.c +++ b/fs/xfs/linux-2.6/xfs_sync.c @@ -270,8 +270,7 @@ xfs_sync_inode_attr( goto out_unlock; } - error = xfs_iflush(ip, (flags & SYNC_WAIT) ? - XFS_IFLUSH_SYNC : XFS_IFLUSH_DELWRI); + error = xfs_iflush(ip, flags); out_unlock: xfs_iunlock(ip, XFS_ILOCK_SHARED); @@ -460,16 +459,18 @@ xfs_quiesce_fs( { int count = 0, pincount; + xfs_reclaim_inodes(mp, 0); xfs_flush_buftarg(mp->m_ddev_targp, 0); - xfs_reclaim_inodes(mp, XFS_IFLUSH_DELWRI_ELSE_ASYNC); /* * 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. + * 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) { @@ -585,7 +586,7 @@ xfs_sync_worker( if (!(mp->m_flags & XFS_MOUNT_RDONLY)) { xfs_log_force(mp, 0); - xfs_reclaim_inodes(mp, XFS_IFLUSH_DELWRI_ELSE_ASYNC); + xfs_reclaim_inodes(mp, 0); /* dgc: errors ignored here */ error = xfs_qm_sync(mp, SYNC_TRYLOCK); error = xfs_sync_fsdata(mp, SYNC_TRYLOCK); @@ -719,21 +720,42 @@ __xfs_inode_clear_reclaim_tag( * shutdown EIO unpin and reclaim * clean, unpinned 0 reclaim * stale, unpinned 0 reclaim - * clean, pinned(*) 0 unpin and reclaim - * stale, pinned 0 unpin and reclaim - * dirty, async 0 block on flush lock, reclaim - * dirty, sync flush 0 block on flush lock, 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 => unpin + * pinned, delwri => requeue + * pinned, sync => unpin * stale => reclaim * clean => reclaim - * dirty => flush, wait and reclaim + * dirty, delwri => flush and requeue + * dirty, sync => flush, wait and reclaim */ STATIC int xfs_reclaim_inode( @@ -741,7 +763,7 @@ xfs_reclaim_inode( struct xfs_perag *pag, int sync_mode) { - int error; + int error = 0; /* * The radix tree lock here protects a thread in xfs_iget from racing @@ -761,7 +783,11 @@ xfs_reclaim_inode( write_unlock(&pag->pag_ici_lock); xfs_ilock(ip, XFS_ILOCK_EXCL); - xfs_iflock(ip); + if (!xfs_iflock_nowait(ip)) { + if (!(sync_mode & SYNC_WAIT)) + goto out; + xfs_iflock(ip); + } if (is_bad_inode(VFS_I(ip))) goto reclaim; @@ -769,8 +795,13 @@ xfs_reclaim_inode( xfs_iunpin_wait(ip); goto reclaim; } - if (xfs_ipincount(ip)) + 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)) @@ -778,27 +809,43 @@ xfs_reclaim_inode( /* Now we have an inode that needs flushing */ error = xfs_iflush(ip, sync_mode); - if (!error) { - switch(sync_mode) { - case XFS_IFLUSH_DELWRI_ELSE_ASYNC: - case XFS_IFLUSH_DELWRI: - case XFS_IFLUSH_ASYNC: - case XFS_IFLUSH_DELWRI_ELSE_SYNC: - case XFS_IFLUSH_SYNC: - /* IO issued, synchronise with IO completion */ - xfs_iflock(ip); - break; - default: - ASSERT(0); - break; - } + if (sync_mode & SYNC_WAIT) { + 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 relcaim the inode and + * pass on the error. + */ + if (error && !XFS_FORCED_SHUTDOWN(ip->i_mount)) { + xfs_fs_cmn_err(CE_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_ireclaim(ip); - return 0; + return error; + } int |