[PATCH 3.18 040/222] Btrfs: fix inode eviction infinite loop after extent_same ioctl

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



From: Filipe Manana <fdmanana@xxxxxxxx>

[ Upstream commit HEAD ]

commit 113e8283869b9855c8b999796aadd506bbac155f upstream.

If we pass a length of 0 to the extent_same ioctl, we end up locking an
extent range with a start offset greater then its end offset (if the
destination file's offset is greater than zero). This results in a warning
from extent_io.c:insert_state through the following call chain:

  btrfs_extent_same()
    btrfs_double_lock()
      lock_extent_range()
        lock_extent(inode->io_tree, offset, offset + len - 1)
          lock_extent_bits()
            __set_extent_bit()
              insert_state()
                --> WARN_ON(end < start)

This leads to an infinite loop when evicting the inode. This is the same
problem that my previous patch titled
"Btrfs: fix inode eviction infinite loop after cloning into it" addressed
but for the extent_same ioctl instead of the clone ioctl.

Signed-off-by: Filipe Manana <fdmanana@xxxxxxxx>
Reviewed-by: Omar Sandoval <osandov@xxxxxxxxxxx>
Signed-off-by: Chris Mason <clm@xxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

(cherry picked from commit 9dc106617d5669a6f8d86e08f620dc2fb0413e21)
Signed-off-by: Sasha Levin <sasha.levin@xxxxxxxxxx>
---
 fs/btrfs/ioctl.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index 96ea36f..5c414fe 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -2925,6 +2925,9 @@ static int btrfs_extent_same(struct inode *src, u64 loff, u64 len,
 	if (src == dst)
 		return -EINVAL;
 
+	if (len == 0)
+		return 0;
+
 	btrfs_double_lock(src, loff, dst, dst_loff, len);
 
 	ret = extent_same_check_offsets(src, loff, len);
-- 
2.1.0

--
To unsubscribe from this list: send the line "unsubscribe stable" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html




[Index of Archives]     [Linux Kernel]     [Kernel Development Newbies]     [Linux USB Devel]     [Video for Linux]     [Linux Audio Users]     [Yosemite Hiking]     [Linux Kernel]     [Linux SCSI]