diff options
authorJeff Mahoney <jeffm@suse.com>2015-09-11 21:44:17 -0400
committerBen Hutchings <ben@decadent.org.uk>2015-10-13 03:46:09 +0100
commit6910b17342022468f9793c70d57a835d44187bd7 (patch)
parente52ea4cc8b0298e06c28469c8e8b8d9cecaed0f3 (diff)
btrfs: skip waiting on ordered range for special files
commit a30e577c96f59b1e1678ea5462432b09bf7d5cbc upstream. In btrfs_evict_inode, we properly truncate the page cache for evicted inodes but then we call btrfs_wait_ordered_range for every inode as well. It's the right thing to do for regular files but results in incorrect behavior for device inodes for block devices. filemap_fdatawrite_range gets called with inode->i_mapping which gets resolved to the block device inode before getting passed to wbc_attach_fdatawrite_inode and ultimately to inode_to_bdi. What happens next depends on whether there's an open file handle associated with the inode. If there is, we write to the block device, which is unexpected behavior. If there isn't, we through normally and inode->i_data is used. We can also end up racing against open/close which can result in crashes when i_mapping points to a block device inode that has been closed. Since there can't be any page cache associated with special file inodes, it's safe to skip the btrfs_wait_ordered_range call entirely and avoid the problem. Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=100911 Tested-by: Christoph Biedl <linux-kernel.bfrz@manchmal.in-ulm.de> Signed-off-by: Jeff Mahoney <jeffm@suse.com> Reviewed-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
1 files changed, 2 insertions, 1 deletions
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 622d322..cb10cb9 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -3518,7 +3518,8 @@ void btrfs_evict_inode(struct inode *inode)
goto no_delete;
/* do we really want it for ->i_nlink > 0 and zero btrfs_root_refs? */
- btrfs_wait_ordered_range(inode, 0, (u64)-1);
+ if (!special_file(inode->i_mode))
+ btrfs_wait_ordered_range(inode, 0, (u64)-1);
if (root->fs_info->log_root_recovering) {