diff options
| author | kaixuxia <xiakaixu1987@gmail.com> | 2019-11-12 08:34:23 -0800 |
|---|---|---|
| committer | Darrick J. Wong <darrick.wong@oracle.com> | 2019-11-13 11:13:45 -0800 |
| commit | 93597ae8dac0149b5c00b787cba6bf7ba213e666 (patch) | |
| tree | 81d81c6c0c66b66c379427ebf686adfb0ae4cb12 /fs/xfs/xfs_inode.c | |
| parent | 048a35d2f0b4cfeb24cbb7fe59e78124d8e7dc73 (diff) | |
xfs: Fix deadlock between AGI and AGF when target_ip exists in xfs_rename()
When target_ip exists in xfs_rename(), the xfs_dir_replace() call may
need to hold the AGF lock to allocate more blocks, and then invoking
the xfs_droplink() call to hold AGI lock to drop target_ip onto the
unlinked list, so we get the lock order AGF->AGI. This would break the
ordering constraint on AGI and AGF locking - inode allocation locks
the AGI, then can allocate a new extent for new inodes, locking the
AGF after the AGI.
In this patch we check whether the replace operation need more
blocks firstly. If so, acquire the agi lock firstly to preserve
locking order(AGI/AGF). Actually, the locking order problem only
occurs when we are locking the AGI/AGF of the same AG. For multiple
AGs the AGI lock will be released after the transaction committed.
Signed-off-by: kaixuxia <kaixuxia@tencent.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
[darrick: reword the comment]
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Diffstat (limited to 'fs/xfs/xfs_inode.c')
| -rw-r--r-- | fs/xfs/xfs_inode.c | 17 |
1 files changed, 17 insertions, 0 deletions
diff --git a/fs/xfs/xfs_inode.c b/fs/xfs/xfs_inode.c index 76424fcc189d..401da197f012 100644 --- a/fs/xfs/xfs_inode.c +++ b/fs/xfs/xfs_inode.c @@ -3210,6 +3210,7 @@ xfs_rename( struct xfs_trans *tp; struct xfs_inode *wip = NULL; /* whiteout inode */ struct xfs_inode *inodes[__XFS_SORT_INODES]; + struct xfs_buf *agibp; int num_inodes = __XFS_SORT_INODES; bool new_parent = (src_dp != target_dp); bool src_is_directory = S_ISDIR(VFS_I(src_ip)->i_mode); @@ -3374,6 +3375,22 @@ xfs_rename( * In case there is already an entry with the same * name at the destination directory, remove it first. */ + + /* + * Check whether the replace operation will need to allocate + * blocks. This happens when the shortform directory lacks + * space and we have to convert it to a block format directory. + * When more blocks are necessary, we must lock the AGI first + * to preserve locking order (AGI -> AGF). + */ + if (xfs_dir2_sf_replace_needblock(target_dp, src_ip->i_ino)) { + error = xfs_read_agi(mp, tp, + XFS_INO_TO_AGNO(mp, target_ip->i_ino), + &agibp); + if (error) + goto out_trans_cancel; + } + error = xfs_dir_replace(tp, target_dp, target_name, src_ip->i_ino, spaceres); if (error) |