Commit 78ad4ce0 authored Sep 08, 2017 by Naohiro Aota Committed by David Sterba Sep 26, 2017

btrfs: propagate error to btrfs_cmp_data_prepare caller



btrfs_cmp_data_prepare() (almost) always returns 0 i.e. ignoring errors
from gather_extent_pages(). While the pages are freed by
btrfs_cmp_data_free(), cmp->num_pages still has > 0. Then,
btrfs_extent_same() try to access the already freed pages causing faults
(or violates PageLocked assertion).

This patch just return the error as is so that the caller stop the process.

Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
Fixes: f4414602 ("btrfs: fix deadlock with extent-same and readpage")
Cc: <stable@vger.kernel.org> # 4.2
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

parent 6d6d2829

fs/btrfs/ioctl.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -3028,7 +3028,7 @@ static int btrfs_cmp_data_prepare(struct inode *src, u64 loff,
		out:
		if (ret)
		btrfs_cmp_data_free(cmp);
		return 0;
		return ret;
		}

		static int btrfs_cmp_data(u64 len, struct cmp_pages *cmp)

Admin message