From: J. Bruce Fields <bfields@xxxxxxxxxxxx>
Normally we could skip ever having to allocate a block in the case where
the client asks for a non-blocking lock, or asks for a blocking lock that
succeeds immediately.
However we're going to want to always look up a block first in order to
check whether we're revisiting a deferred lock call, and to be prepared to
handle the case where the filesystem returns -EINPROGRESS--in that case we
want to make sure the lock we've given the filesystem is the one embedded
in the block that we'll use to track the deferred request.
Signed-off-by: Marc Eshel <eshel@xxxxxxxxxxxxxxx>
Signed-off-by: J. Bruce Fields <bfields@xxxxxxxxxxxxxx>
---
fs/lockd/svclock.c | 34 +++++++++++-----------------------
1 files changed, 11 insertions(+), 23 deletions(-)
diff --git a/fs/lockd/svclock.c b/fs/lockd/svclock.c
index 21185a7..134a40e 100644
--- a/fs/lockd/svclock.c
+++ b/fs/lockd/svclock.c
@@ -471,7 +471,7 @@ __be32
nlmsvc_lock(struct svc_rqst *rqstp, struct nlm_file *file,
struct nlm_lock *lock, int wait, struct nlm_cookie *cookie)
{
- struct nlm_block *block, *newblock = NULL;
+ struct nlm_block *block = NULL;
int error;
__be32 ret;
@@ -484,17 +484,20 @@ nlmsvc_lock(struct svc_rqst *rqstp, struct nlm_file *file,
wait);
- lock->fl.fl_flags &= ~FL_SLEEP;
-again:
/* Lock file against concurrent access */
mutex_lock(&file->f_mutex);
- /* Get existing block (in case client is busy-waiting) */
+ /* Get existing block (in case client is busy-waiting)
+ * or create new block
+ */
block = nlmsvc_lookup_block(file, lock);
if (block == NULL) {
- if (newblock != NULL)
- lock = &newblock->b_call->a_args.lock;
- } else
+ block = nlmsvc_create_block(rqstp, file, lock, cookie);
+ ret = nlm_lck_denied_nolocks;
+ if (block == NULL)
+ goto out;
lock = &block->b_call->a_args.lock;
+ } else
+ lock->fl.fl_flags &= ~FL_SLEEP;
error = posix_lock_file(file->f_file, &lock->fl);
lock->fl.fl_flags &= ~FL_SLEEP;
@@ -520,26 +523,11 @@ again:
goto out;
ret = nlm_lck_blocked;
- if (block != NULL)
- goto out;
-
- /* If we don't have a block, create and initialize it. Then
- * retry because we may have slept in kmalloc. */
- /* We have to release f_mutex as nlmsvc_create_block may try to
- * to claim it while doing host garbage collection */
- if (newblock == NULL) {
- mutex_unlock(&file->f_mutex);
- dprintk("lockd: blocking on this lock (allocating).\n");
- if (!(newblock = nlmsvc_create_block(rqstp, file, lock, cookie)))
- return nlm_lck_denied_nolocks;
- goto again;
- }
/* Append to list of blocked */
- nlmsvc_insert_block(newblock, NLM_NEVER);
+ nlmsvc_insert_block(block, NLM_NEVER);
out:
mutex_unlock(&file->f_mutex);
- nlmsvc_release_block(newblock);
nlmsvc_release_block(block);
dprintk("lockd: nlmsvc_lock returned %u\n", ret);
return ret;
--
1.4.4.1
-
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