diff options
| author | Weston Andros Adamson <dros@primarydata.com> | 2014-09-15 14:14:40 -0400 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2014-10-05 13:41:00 -0700 |
| commit | 28c86fda6b1d637bac19a72c5db5cce90b043b95 (patch) | |
| tree | 345f61663667b81cfce80db6ef18935a4a1dc37e /fs | |
| parent | 6483253a3f2ce76bee51e0ac7f98d6c0ee8df08d (diff) | |
nfs: fix nonblocking calls to nfs_page_group_lock
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@primarydata.com>
Reviewed-by: Peng Tao <tao.peng@primarydata.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'fs')
| -rw-r--r-- | fs/nfs/pagelist.c | 23 |
1 files changed, 14 insertions, 9 deletions
diff --git a/fs/nfs/pagelist.c b/fs/nfs/pagelist.c index b4ebd4d7d976..c27a05c27c11 100644 --- a/fs/nfs/pagelist.c +++ b/fs/nfs/pagelist.c @@ -149,24 +149,29 @@ static int nfs_wait_bit_uninterruptible(void *word) * * 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; - WARN_ON_ONCE(ret > 0); - return ret; + if (!nonblock) + return wait_on_bit_lock(&head->wb_flags, PG_HEADLOCK, + nfs_wait_bit_uninterruptible, + TASK_UNINTERRUPTIBLE); + + return -EAGAIN; } /* |