Btrfs: hold the tree mod lock in __tree_mod_log_rewind
We need to hold the tree mod log lock in __tree_mod_log_rewind since we walk
forward in the tree mod entries, otherwise we'll end up with random entries and
trip the BUG_ON() at the front of __tree_mod_log_rewind. This fixes the panics
people were seeing when running
find /whatever -type f -exec btrfs fi defrag {} \;
Thansk,
Cc: stable@vger.kernel.org
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c
index c32d03d..7921e1d 100644
--- a/fs/btrfs/ctree.c
+++ b/fs/btrfs/ctree.c
@@ -1161,8 +1161,8 @@
* time_seq).
*/
static void
-__tree_mod_log_rewind(struct extent_buffer *eb, u64 time_seq,
- struct tree_mod_elem *first_tm)
+__tree_mod_log_rewind(struct btrfs_fs_info *fs_info, struct extent_buffer *eb,
+ u64 time_seq, struct tree_mod_elem *first_tm)
{
u32 n;
struct rb_node *next;
@@ -1172,6 +1172,7 @@
unsigned long p_size = sizeof(struct btrfs_key_ptr);
n = btrfs_header_nritems(eb);
+ tree_mod_log_read_lock(fs_info);
while (tm && tm->seq >= time_seq) {
/*
* all the operations are recorded with the operator used for
@@ -1226,6 +1227,7 @@
if (tm->index != first_tm->index)
break;
}
+ tree_mod_log_read_unlock(fs_info);
btrfs_set_header_nritems(eb, n);
}
@@ -1274,7 +1276,7 @@
extent_buffer_get(eb_rewin);
btrfs_tree_read_lock(eb_rewin);
- __tree_mod_log_rewind(eb_rewin, time_seq, tm);
+ __tree_mod_log_rewind(fs_info, eb_rewin, time_seq, tm);
WARN_ON(btrfs_header_nritems(eb_rewin) >
BTRFS_NODEPTRS_PER_BLOCK(fs_info->tree_root));
@@ -1350,7 +1352,7 @@
btrfs_set_header_generation(eb, old_generation);
}
if (tm)
- __tree_mod_log_rewind(eb, time_seq, tm);
+ __tree_mod_log_rewind(root->fs_info, eb, time_seq, tm);
else
WARN_ON(btrfs_header_level(eb) != 0);
WARN_ON(btrfs_header_nritems(eb) > BTRFS_NODEPTRS_PER_BLOCK(root));