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Subject[PATCH 3/3] reiserfs: Relax lock on xattr removing
Date
When we remove an xattr, we call lookup_and_delete_xattr()
that takes some private xattr inodes mutexes. But we hold
the reiserfs lock at this time, which leads to dependency
inversions.

We can safely call lookup_and_delete_xattr() without the
reiserfs lock, where xattr inodes lookups only need the
xattr inodes mutexes.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Christian Kujau <lists@nerdbynature.de>
Cc: Alexander Beregalov <a.beregalov@gmail.com>
Cc: Chris Mason <chris.mason@oracle.com>
Cc: Ingo Molnar <mingo@elte.hu>
---
fs/reiserfs/xattr.c | 12 +++++++++---
1 files changed, 9 insertions(+), 3 deletions(-)

diff --git a/fs/reiserfs/xattr.c b/fs/reiserfs/xattr.c
index 75d3706..4899d78 100644
--- a/fs/reiserfs/xattr.c
+++ b/fs/reiserfs/xattr.c
@@ -451,7 +451,9 @@ static int lookup_and_delete_xattr(struct inode *inode, const char *name)
}

if (dentry->d_inode) {
+ reiserfs_write_lock(inode->i_sb);
err = xattr_unlink(xadir->d_inode, dentry);
+ reiserfs_write_unlock(inode->i_sb);
update_ctime(inode);
}

@@ -485,10 +487,14 @@ reiserfs_xattr_set_handle(struct reiserfs_transaction_handle *th,
if (get_inode_sd_version(inode) == STAT_DATA_V1)
return -EOPNOTSUPP;

- if (!buffer)
- return lookup_and_delete_xattr(inode, name);
-
reiserfs_write_unlock(inode->i_sb);
+
+ if (!buffer) {
+ err = lookup_and_delete_xattr(inode, name);
+ reiserfs_write_lock(inode->i_sb);
+ return err;
+ }
+
dentry = xattr_lookup(inode, name, flags);
if (IS_ERR(dentry)) {
reiserfs_write_lock(inode->i_sb);
--
1.6.2.3


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