tree 80b75191277afe05201fab3e3d1bc50884444626
parent 21380931eb4da4e29ac663d0221581282cbba208
author Chris Mason <chris.mason@oracle.com> 1240843793 -0400
committer Chris Mason <chris.mason@oracle.com> 1240852706 -0400

Btrfs: fix acl caching

Linus noticed the btrfs code to cache acls wasn't properly caching
a NULL acl when the inode didn't have any acls.  This meant the common
case of no acls resulted in expensive btree searches every time the
kernel checked permissions (which is quite often).

This is a modified version of Linus' original patch:

Properly set initial acl fields to BTRFS_ACL_NOT_CACHED in the inode.
This forces an acl lookup when permission checks are done.

Fix btrfs_get_acl to avoid lookups and locking when the inode acls fields
are set to null.

Fix btrfs_get_acl to use the right return value from __btrfs_getxattr
when deciding to cache a NULL acl.  It was storing a NULL acl when
__btrfs_getxattr return -ENOENT, but __btrfs_getxattr was actually returning
-ENODATA for this case.

Signed-off-by: Chris Mason <chris.mason@oracle.com>