Merge git://git.kernel.org/pub/scm/linux/kernel/git/mason/btrfs-unstable

* git://git.kernel.org/pub/scm/linux/kernel/git/mason/btrfs-unstable:
  Btrfs: look for acls during btrfs_read_locked_inode
  Btrfs: fix acl caching
  Btrfs: Fix a bunch of printk() warnings.
  Btrfs: Fix a trivial warning using max() of u64 vs ULL.
  Btrfs: remove unused btrfs_bit_radix slab
  Btrfs: ratelimit IO error printks
  Btrfs: remove #if 0 code
  Btrfs: When shrinking, only update disk size on success
  Btrfs: fix deadlocks and stalls on dead root removal
  Btrfs: fix fallocate deadlock on inode extent lock
  Btrfs: kill btrfs_cache_create
  Btrfs: don't export symbols
  Btrfs: simplify makefile
  Btrfs: try to keep a healthy ratio of metadata vs data block groups

1 files changed, 13 insertions, 5 deletions

diff --git a/fs/btrfs/acl.c b/fs/btrfs/acl.c
index 7fdd184a528..cbba000dccb 100644
--- a/fs/btrfs/acl.c
+++ b/fs/btrfs/acl.c
@@ -60,15 +60,20 @@ static struct posix_acl *btrfs_get_acl(struct inode *inode, int type)
 		return ERR_PTR(-EINVAL);
 	}
 
+	/* Handle the cached NULL acl case without locking */
+	acl = ACCESS_ONCE(*p_acl);
+	if (!acl)
+		return acl;
+
 	spin_lock(&inode->i_lock);
-	if (*p_acl != BTRFS_ACL_NOT_CACHED)
-		acl = posix_acl_dup(*p_acl);
+	acl = *p_acl;
+	if (acl != BTRFS_ACL_NOT_CACHED)
+		acl = posix_acl_dup(acl);
 	spin_unlock(&inode->i_lock);
 
-	if (acl)
+	if (acl != BTRFS_ACL_NOT_CACHED)
 		return acl;
 
-
 	size = __btrfs_getxattr(inode, name, "", 0);
 	if (size > 0) {
 		value = kzalloc(size, GFP_NOFS);
@@ -80,9 +85,12 @@ static struct posix_acl *btrfs_get_acl(struct inode *inode, int type)
 			btrfs_update_cached_acl(inode, p_acl, acl);
 		}
 		kfree(value);
-	} else if (size == -ENOENT) {
+	} else if (size == -ENOENT || size == -ENODATA || size == 0) {
+		/* FIXME, who returns -ENOENT?  I think nobody */
 		acl = NULL;
 		btrfs_update_cached_acl(inode, p_acl, acl);
+	} else {
+		acl = ERR_PTR(-EIO);
 	}
 
 	return acl;