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authorChris Mason <clm@fb.com>2014-01-09 17:28:00 -0800
committerChris Mason <clm@fb.com>2014-01-29 07:06:30 -0800
commit90d3e592e99b8e374ead2b45148abf506493a959 (patch)
tree9e2b61f449524e988dacb04a770b87a2e3fddc23
parent514ac8ad8793a097c0c9d89202c642479d6dfa34 (diff)
Btrfs: setup inode location during btrfs_init_inode_locked
We have a race during inode init because the BTRFS_I(inode)->location is setup after the inode hash table lock is dropped. btrfs_find_actor uses the location field, so our search might not find an existing inode in the hash table if we race with the inode init code. This commit changes things to setup the location field sooner. Also the find actor now uses only the location objectid to match inodes. For inode hashing, we just need a unique and stable test, it doesn't have to reflect the inode numbers we show to userland. Signed-off-by: Chris Mason <clm@fb.com> CC: stable@vger.kernel.org
-rw-r--r--fs/btrfs/inode.c18
1 files changed, 9 insertions, 9 deletions
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index ad961a598c99..fb74a536add3 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -61,7 +61,7 @@
#include "props.h"
struct btrfs_iget_args {
- u64 ino;
+ struct btrfs_key *location;
struct btrfs_root *root;
};
@@ -4977,7 +4977,9 @@ again:
static int btrfs_init_locked_inode(struct inode *inode, void *p)
{
struct btrfs_iget_args *args = p;
- inode->i_ino = args->ino;
+ inode->i_ino = args->location->objectid;
+ memcpy(&BTRFS_I(inode)->location, args->location,
+ sizeof(*args->location));
BTRFS_I(inode)->root = args->root;
return 0;
}
@@ -4985,19 +4987,19 @@ static int btrfs_init_locked_inode(struct inode *inode, void *p)
static int btrfs_find_actor(struct inode *inode, void *opaque)
{
struct btrfs_iget_args *args = opaque;
- return args->ino == btrfs_ino(inode) &&
+ return args->location->objectid == BTRFS_I(inode)->location.objectid &&
args->root == BTRFS_I(inode)->root;
}
static struct inode *btrfs_iget_locked(struct super_block *s,
- u64 objectid,
+ struct btrfs_key *location,
struct btrfs_root *root)
{
struct inode *inode;
struct btrfs_iget_args args;
- unsigned long hashval = btrfs_inode_hash(objectid, root);
+ unsigned long hashval = btrfs_inode_hash(location->objectid, root);
- args.ino = objectid;
+ args.location = location;
args.root = root;
inode = iget5_locked(s, hashval, btrfs_find_actor,
@@ -5014,13 +5016,11 @@ struct inode *btrfs_iget(struct super_block *s, struct btrfs_key *location,
{
struct inode *inode;
- inode = btrfs_iget_locked(s, location->objectid, root);
+ inode = btrfs_iget_locked(s, location, root);
if (!inode)
return ERR_PTR(-ENOMEM);
if (inode->i_state & I_NEW) {
- BTRFS_I(inode)->root = root;
- memcpy(&BTRFS_I(inode)->location, location, sizeof(*location));
btrfs_read_locked_inode(inode);
if (!is_bad_inode(inode)) {
inode_tree_add(inode);