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@xxxxxxxxxxx>
---
fs/xfs/libxfs/xfs_dir2.c | 30 ++++++++++++++++++++++++++++++
fs/xfs/libxfs/xfs_dir2.h | 2 ++
fs/xfs/xfs_inode.c | 14 ++++++++++++++
3 files changed, 46 insertions(+)
diff --git a/fs/xfs/libxfs/xfs_dir2.c b/fs/xfs/libxfs/xfs_dir2.c
index 867c5de..9d9ae16 100644
--- a/fs/xfs/libxfs/xfs_dir2.c
+++ b/fs/xfs/libxfs/xfs_dir2.c
@@ -463,6 +463,36 @@
}
/*
+ * Check whether the replace operation need more blocks. Ignore
+ * the parameters check since the real replace() call below will
+ * do that.
+ */
+bool
+xfs_dir_replace_needblock(
+ struct xfs_inode *dp,
+ xfs_ino_t inum)
+{
+ int newsize;
+ xfs_dir2_sf_hdr_t *sfp;
+
+ /*
+ * Only convert the shortform directory to block form maybe need
+ * more blocks.
+ */
+ if (dp->i_d.di_format != XFS_DINODE_FMT_LOCAL)
+ return false;
+
+ sfp = (xfs_dir2_sf_hdr_t *)dp->i_df.if_u1.if_data;
+ newsize = dp->i_df.if_bytes + (sfp->count + 1) * XFS_INO64_DIFF;
+
+ if (inum > XFS_DIR2_MAX_SHORT_INUM &&
+ sfp->i8count == 0 && newsize > XFS_IFORK_DSIZE(dp))
+ return true;
+ else
+ return false;
+}
+
+/*
* Replace the inode number of a directory entry.
*/
int
diff --git a/fs/xfs/libxfs/xfs_dir2.h b/fs/xfs/libxfs/xfs_dir2.h
index f542447..e436c14 100644
--- a/fs/xfs/libxfs/xfs_dir2.h
+++ b/fs/xfs/libxfs/xfs_dir2.h
@@ -124,6 +124,8 @@ extern int xfs_dir_lookup(struct xfs_trans *tp, struct xfs_inode *dp,
extern int xfs_dir_removename(struct xfs_trans *tp, struct xfs_inode *dp,
struct xfs_name *name, xfs_ino_t ino,
xfs_extlen_t tot);
+extern bool xfs_dir_replace_needblock(struct xfs_inode *dp,
+ xfs_ino_t inum);
extern int xfs_dir_replace(struct xfs_trans *tp, struct xfs_inode *dp,
struct xfs_name *name, xfs_ino_t inum,
xfs_extlen_t tot);
diff --git a/fs/xfs/xfs_inode.c b/fs/xfs/xfs_inode.c
index 18f4b26..c239070 100644
--- a/fs/xfs/xfs_inode.c
+++ b/fs/xfs/xfs_inode.c
@@ -3196,6 +3196,7 @@ struct xfs_iunlink {
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);
@@ -3361,6 +3362,19 @@ struct xfs_iunlink {
* In case there is already an entry with the same
* name at the destination directory, remove it first.
*/
+
+ /*
+ * Check whether the replace operation need more blocks.
+ * If so, acquire the agi lock firstly to preserve locking
+ * order(AGI/AGF).
+ */
+ if (xfs_dir_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)
--
1.8.3.1
