cifs: fix oops while traversing open file list (try #4)
authorShirish Pargaonkar <shirishpargaonkar@gmail.com>
Mon, 21 May 2012 14:20:12 +0000 (09:20 -0500)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Sat, 9 Jun 2012 15:36:07 +0000 (00:36 +0900)
commit27ab30eb965b9d26c5811f5505d95c8ede08c580
tree2b74dd981ce60b10b4876f4f027f712315b08507
parent444b7bce3152cc6ef1fb599331d053c9c40eb374
cifs: fix oops while traversing open file list (try #4)

commit 2c0c2a08bed7a3b791f88d09d16ace56acb3dd98 upstream.

While traversing the linked list of open file handles, if the identfied
file handle is invalid, a reopen is attempted and if it fails, we
resume traversing where we stopped and cifs can oops while accessing
invalid next element, for list might have changed.

So mark the invalid file handle and attempt reopen if no
valid file handle is found in rest of the list.
If reopen fails, move the invalid file handle to the end of the list
and start traversing the list again from the begining.
Repeat this four times before giving up and returning an error if
file reopen keeps failing.

Signed-off-by: Shirish Pargaonkar <shirishpargaonkar@gmail.com>
Reviewed-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
fs/cifs/cifsglob.h
fs/cifs/file.c