[PATCH 4.4 35/67] btrfs: fix deadlock when writing out space cache

[Greg Kroah-Hartman]

4.4-stable review patch.  If anyone has any objections, please let me know.

--

From: Josef Bacik 


[ Upstream commit b77000ed558daa3bef0899d29bf171b8c9b5e6a8 ]

If we fail to prepare our pages for whatever reason (out of memory in
our case) we need to make sure to drop the block_group->data_rwsem,
otherwise hilarity ensues.

Signed-off-by: Josef Bacik 
Reviewed-by: Omar Sandoval 
Reviewed-by: Liu Bo 
Reviewed-by: David Sterba 
[ add label and use existing unlocking code ]
Signed-off-by: David Sterba 

Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman 
---
 fs/btrfs/free-space-cache.c |3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

--- a/fs/btrfs/free-space-cache.c
+++ b/fs/btrfs/free-space-cache.c
@@ -1258,7 +1258,7 @@ static int __btrfs_write_out_cache(struc
/* Lock all pages first so we can lock the extent safely. */
ret = io_ctl_prepare_pages(io_ctl, inode, 0);
if (ret)
-   goto out;
+   goto out_unlock;
 
lock_extent_bits(_I(inode)->io_tree, 0, i_size_read(inode) - 1,
 0, _state);
@@ -1351,6 +1351,7 @@ out_nospc_locked:
 out_nospc:
cleanup_write_cache_enospc(inode, io_ctl, _state, _list);
 
+out_unlock:
if (block_group && (block_group->flags & BTRFS_BLOCK_GROUP_DATA))
up_write(_group->data_rwsem);
 

[PATCH 4.4 35/67] btrfs: fix deadlock when writing out space cache

[Greg Kroah-Hartman]

4.4-stable review patch.  If anyone has any objections, please let me know.

--

From: Josef Bacik 


[ Upstream commit b77000ed558daa3bef0899d29bf171b8c9b5e6a8 ]

If we fail to prepare our pages for whatever reason (out of memory in
our case) we need to make sure to drop the block_group->data_rwsem,
otherwise hilarity ensues.

Signed-off-by: Josef Bacik 
Reviewed-by: Omar Sandoval 
Reviewed-by: Liu Bo 
Reviewed-by: David Sterba 
[ add label and use existing unlocking code ]
Signed-off-by: David Sterba 

Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman 
---
 fs/btrfs/free-space-cache.c |3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

--- a/fs/btrfs/free-space-cache.c
+++ b/fs/btrfs/free-space-cache.c
@@ -1258,7 +1258,7 @@ static int __btrfs_write_out_cache(struc
/* Lock all pages first so we can lock the extent safely. */
ret = io_ctl_prepare_pages(io_ctl, inode, 0);
if (ret)
-   goto out;
+   goto out_unlock;
 
lock_extent_bits(_I(inode)->io_tree, 0, i_size_read(inode) - 1,
 0, _state);
@@ -1351,6 +1351,7 @@ out_nospc_locked:
 out_nospc:
cleanup_write_cache_enospc(inode, io_ctl, _state, _list);
 
+out_unlock:
if (block_group && (block_group->flags & BTRFS_BLOCK_GROUP_DATA))
up_write(_group->data_rwsem);