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 -- 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