diff options
Diffstat (limited to 'fs')
| -rw-r--r-- | fs/xfs/xfs_reflink.c | 48 |
1 files changed, 47 insertions, 1 deletions
diff --git a/fs/xfs/xfs_reflink.c b/fs/xfs/xfs_reflink.c index bcc2ad4f0899..bac464f0bc59 100644 --- a/fs/xfs/xfs_reflink.c +++ b/fs/xfs/xfs_reflink.c @@ -1245,6 +1245,50 @@ err: } /* + * Grab the exclusive iolock for a data copy from src to dest, making + * sure to abide vfs locking order (lowest pointer value goes first) and + * breaking the pnfs layout leases on dest before proceeding. The loop + * is needed because we cannot call the blocking break_layout() with the + * src iolock held, and therefore have to back out both locks. + */ +static int +xfs_iolock_two_inodes_and_break_layout( + struct inode *src, + struct inode *dest) +{ + int error; + +retry: + if (src < dest) { + inode_lock(src); + inode_lock_nested(dest, I_MUTEX_NONDIR2); + } else { + /* src >= dest */ + inode_lock(dest); + } + + error = break_layout(dest, false); + if (error == -EWOULDBLOCK) { + inode_unlock(dest); + if (src < dest) + inode_unlock(src); + error = break_layout(dest, true); + if (error) + return error; + goto retry; + } + if (error) { + inode_unlock(dest); + if (src < dest) + inode_unlock(src); + return error; + } + if (src > dest) + inode_lock_nested(src, I_MUTEX_NONDIR2); + return 0; +} + +/* * Link a range of blocks from one file to another. */ int @@ -1274,7 +1318,9 @@ xfs_reflink_remap_range( return -EIO; /* Lock both files against IO */ - lock_two_nondirectories(inode_in, inode_out); + ret = xfs_iolock_two_inodes_and_break_layout(inode_in, inode_out); + if (ret) + return ret; if (same_inode) xfs_ilock(src, XFS_MMAPLOCK_EXCL); else |