This is a note to let you know that I've just added the patch titled
nfs: fix nonblocking calls to nfs_page_group_lock
to the 3.16-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
nfs-fix-nonblocking-calls-to-nfs_page_group_lock.patch
and it can be found in the queue-3.16 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From trond.myklebust@xxxxxxxxxxxxxxx Thu Oct 2 16:49:33 2014
From: Trond Myklebust <trond.myklebust@xxxxxxxxxxxxxxx>
Date: Mon, 15 Sep 2014 14:14:40 -0400
Subject: nfs: fix nonblocking calls to nfs_page_group_lock
To: stable@xxxxxxxxxxxxxxx
Cc: Weston Andros Adamson <dros@xxxxxxxxxxxxxxx>, linux-nfs@xxxxxxxxxxxxxxx
Message-ID: <1410804885-17228-10-git-send-email-trond.myklebust@xxxxxxxxxxxxxxx>
From: Weston Andros Adamson <dros@xxxxxxxxxxxxxxx>
commit bc8a309e88a86205fc3e17f06e42a2e56fc6f807 upstream.
nfs_page_group_lock was calling wait_on_bit_lock even when told not to
block. Fix by first trying test_and_set_bit, followed by wait_on_bit_lock
if and only if blocking is allowed. Return -EAGAIN if nonblocking and the
test_and_set of the bit was already locked.
Signed-off-by: Weston Andros Adamson <dros@xxxxxxxxxxxxxxx>
Reviewed-by: Peng Tao <tao.peng@xxxxxxxxxxxxxxx>
Signed-off-by: Trond Myklebust <trond.myklebust@xxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
fs/nfs/pagelist.c | 23 ++++++++++++++---------
1 file changed, 14 insertions(+), 9 deletions(-)
--- a/fs/nfs/pagelist.c
+++ b/fs/nfs/pagelist.c
@@ -149,24 +149,29 @@ static int nfs_wait_bit_uninterruptible(
*
* this lock must be held if modifying the page group list
*
- * returns result from wait_on_bit_lock: 0 on success, < 0 on error
+ * return 0 on success, < 0 on error: -EDELAY if nonblocking or the
+ * result from wait_on_bit_lock
+ *
+ * NOTE: calling with nonblock=false should always have set the
+ * lock bit (see fs/buffer.c and other uses of wait_on_bit_lock
+ * with TASK_UNINTERRUPTIBLE), so there is no need to check the result.
*/
int
nfs_page_group_lock(struct nfs_page *req, bool nonblock)
{
struct nfs_page *head = req->wb_head;
- int ret;
WARN_ON_ONCE(head != head->wb_head);
- do {
- ret = wait_on_bit_lock(&head->wb_flags, PG_HEADLOCK,
- nfs_wait_bit_uninterruptible,
- TASK_UNINTERRUPTIBLE);
- } while (!nonblock && ret != 0);
+ if (!test_and_set_bit(PG_HEADLOCK, &head->wb_flags))
+ return 0;
+
+ if (!nonblock)
+ return wait_on_bit_lock(&head->wb_flags, PG_HEADLOCK,
+ nfs_wait_bit_uninterruptible,
+ TASK_UNINTERRUPTIBLE);
- WARN_ON_ONCE(ret > 0);
- return ret;
+ return -EAGAIN;
}
/*
Patches currently in stable-queue which might be from trond.myklebust@xxxxxxxxxxxxxxx are
queue-3.16/nfs-move-nfs_pgio_data-and-remove-nfs_rw_header.patch
queue-3.16/nfs-use-blocking-page_group_lock-in-add_request.patch
queue-3.16/nfs-remove-pgio_header-refcount-related-cleanup.patch
queue-3.16/pnfs-add-pnfs_put_lseg_async.patch
queue-3.16/nfs-can_coalesce_requests-must-enforce-contiguity.patch
queue-3.16/nfs-disallow-duplicate-pages-in-pgio-page-vectors.patch
queue-3.16/nfs-fix-error-handling-in-lock_and_join_requests.patch
queue-3.16/nfs-change-nfs_page_group_lock-argument.patch
queue-3.16/nfsv4-nfs4_state_manager-vs.-nfs_server_remove_lists.patch
queue-3.16/nfsv4-fix-another-bug-in-the-close-open_downgrade-code.patch
queue-3.16/nfs-check-wait_on_bit_lock-err-in-page_group_lock.patch
queue-3.16/nfs-don-t-sleep-with-inode-lock-in-lock_and_join_requests.patch
queue-3.16/nfs-rename-members-of-nfs_pgio_data.patch
queue-3.16/nfs-fix-nonblocking-calls-to-nfs_page_group_lock.patch
queue-3.16/nfs-merge-nfs_pgio_data-into-_header.patch
queue-3.16/nfs-clear_request_commit-while-holding-i_lock.patch
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