diff options
Diffstat (limited to 'fs/xfs/xfs_aops.c')
| -rw-r--r-- | fs/xfs/xfs_aops.c | 30 |
1 files changed, 26 insertions, 4 deletions
diff --git a/fs/xfs/xfs_aops.c b/fs/xfs/xfs_aops.c index 0dbb9e7..0fd7c2b 100644 --- a/fs/xfs/xfs_aops.c +++ b/fs/xfs/xfs_aops.c @@ -1146,7 +1146,14 @@ __xfs_get_blocks( if (!create && direct && offset >= i_size_read(inode)) return 0; - if (create) { + /* + * Direct I/O is usually done on preallocated files, so try getting + * a block mapping without an exclusive lock first. For buffered + * writes we already have the exclusive iolock anyway, so avoiding + * a lock roundtrip here by taking the ilock exclusive from the + * beginning is a useful micro optimization. + */ + if (create && !direct) { lockmode = XFS_ILOCK_EXCL; xfs_ilock(ip, lockmode); } else { @@ -1169,22 +1176,37 @@ __xfs_get_blocks( (imap.br_startblock == HOLESTARTBLOCK || imap.br_startblock == DELAYSTARTBLOCK))) { if (direct) { + /* + * Drop the ilock in preparation for starting the block + * allocation transaction. It will be retaken + * exclusively inside xfs_iomap_write_direct for the + * actual allocation. + */ + xfs_iunlock(ip, lockmode); error = xfs_iomap_write_direct(ip, offset, size, &imap, nimaps); + if (error) + return -error; } else { + /* + * Delalloc reservations do not require a transaction, + * we can go on without dropping the lock here. + */ error = xfs_iomap_write_delay(ip, offset, size, &imap); + if (error) + goto out_unlock; + + xfs_iunlock(ip, lockmode); } - if (error) - goto out_unlock; trace_xfs_get_blocks_alloc(ip, offset, size, 0, &imap); } else if (nimaps) { trace_xfs_get_blocks_found(ip, offset, size, 0, &imap); + xfs_iunlock(ip, lockmode); } else { trace_xfs_get_blocks_notfound(ip, offset, size); goto out_unlock; } - xfs_iunlock(ip, lockmode); if (imap.br_startblock != HOLESTARTBLOCK && imap.br_startblock != DELAYSTARTBLOCK) { |