diff options
| author | Weston Andros Adamson <dros@primarydata.com> | 2014-08-08 11:00:54 -0400 |
|---|---|---|
| committer | Trond Myklebust <trond.myklebust@primarydata.com> | 2014-08-22 18:04:42 -0400 |
| commit | bc8a309e88a86205fc3e17f06e42a2e56fc6f807 (patch) | |
| tree | 3a3df69f6e7a6e16fc6a816e2e4ee1d0544ec8cb /fs | |
| parent | fd2f3a06d30c85a17cf035ebc60c88c2a13a8ece (diff) | |
nfs: fix nonblocking calls to nfs_page_group_lock
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>
Diffstat (limited to 'fs')
| -rw-r--r-- | fs/nfs/pagelist.c | 21 |
1 files changed, 13 insertions, 8 deletions
diff --git a/fs/nfs/pagelist.c b/fs/nfs/pagelist.c index 7efa61586bc4..89d5d433e351 100644 --- a/fs/nfs/pagelist.c +++ b/fs/nfs/pagelist.c @@ -143,23 +143,28 @@ nfs_iocounter_wait(struct nfs_io_counter *c) * * 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, - 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, + TASK_UNINTERRUPTIBLE); + + return -EAGAIN; } /* |