a7y18lte-ubports/android_kernel_samsung_universal7885
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btrfs: fix deadlock when writing out space cache

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[ 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 <jbacik@fb.com>
Reviewed-by: Omar Sandoval <osandov@fb.com>
Reviewed-by: Liu Bo <bo.li.liu@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
[ add label and use existing unlocking code ]
Signed-off-by: David Sterba <dsterba@suse.com>

Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Josef Bacik 2017-11-15 16:20:52 -05:00 committed by Greg Kroah-Hartman
parent 4870fb9722
commit de3d7e1346
1 changed files with 2 additions and 1 deletions
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3
fs/btrfs/free-space-cache.c
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@ -1258,7 +1258,7 @@ static int __btrfs_write_out_cache(struct btrfs_root *root, struct inode *inode,
/* 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(&BTRFS_I(inode)->io_tree, 0, i_size_read(inode) - 1,
0, &cached_state);
@ -1351,6 +1351,7 @@ out_nospc_locked:
out_nospc:
cleanup_write_cache_enospc(inode, io_ctl, &cached_state, &bitmap_list);
out_unlock:
if (block_group && (block_group->flags & BTRFS_BLOCK_GROUP_DATA))
up_write(&block_group->data_rwsem);