https://github.com/torvalds/linux
Revision b98749cac4a695f084a5ff076f4510b23e353ecd authored by Aurelien Aptel on 29 March 2019, 09:49:12 UTC, committed by Steve French on 16 April 2019, 14:38:38 UTC
In the oplock break handler, writing pending changes from pages puts
the FileInfo handle. If the refcount reaches zero it closes the handle
and waits for any oplock break handler to return, thus causing a deadlock.

To prevent this situation:

* We add a wait flag to cifsFileInfo_put() to decide whether we should
  wait for running/pending oplock break handlers

* We keep an additionnal reference of the SMB FileInfo handle so that
  for the rest of the handler putting the handle won't close it.
  - The ref is bumped everytime we queue the handler via the
    cifs_queue_oplock_break() helper.
  - The ref is decremented at the end of the handler

This bug was triggered by xfstest 464.

Also important fix to address the various reports of
oops in smb2_push_mandatory_locks

Signed-off-by: Aurelien Aptel <aaptel@suse.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Reviewed-by: Pavel Shilovsky <pshilov@microsoft.com>
CC: Stable <stable@vger.kernel.org>
1 parent e6d0fb7
History
Tip revision: b98749cac4a695f084a5ff076f4510b23e353ecd authored by Aurelien Aptel on 29 March 2019, 09:49:12 UTC
CIFS: keep FileInfo handle live during oplock break
Tip revision: b98749c
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