lockd: Fix server-side lock blocking code (09c7938c) · Commits · e / devices / android_kernel_xiaomi_markw

fs/lockd/svclock.c

+40 −33

Original line number	Diff line number	Diff line
		@@ -193,6 +193,7 @@ nlmsvc_create_block(struct svc_rqst rqstp, struct nlm_file file,
		goto failed_free;

		/* Set notifier function for VFS, and init args */
		block->b_call.a_args.lock.fl.fl_flags \|= FL_SLEEP;
		block->b_call.a_args.lock.fl.fl_lmops = &nlmsvc_lock_operations;
		block->b_call.a_args.cookie = cookie; / see above */

		@@ -228,18 +229,17 @@ failed:
		* can be closed hereafter.
		*/
		static int
		nlmsvc_delete_block(struct nlm_block *block, int unlock)
		nlmsvc_delete_block(struct nlm_block *block)
		{
		struct file_lock *fl = &block->b_call.a_args.lock.fl;
		struct nlm_file *file = block->b_file;
		struct nlm_block **bp;
		int status = 0;
		int status;

		dprintk("lockd: deleting block %p...\n", block);

		/* Remove block from list */
		nlmsvc_remove_block(block);
		if (unlock)
		status = posix_unblock_lock(file->f_file, fl);

		/* If the block is in the middle of a GRANT callback,
		@@ -282,7 +282,7 @@ nlmsvc_traverse_blocks(struct nlm_host host, struct nlm_file file, int action)
		block->b_host->h_inuse = 1;
		else if (action == NLM_ACT_UNLOCK) {
		if (host == NULL \|\| host == block->b_host)
		nlmsvc_delete_block(block, 1);
		nlmsvc_delete_block(block);
		}
		}
		up(&file->f_sema);
		@@ -297,7 +297,7 @@ u32
		nlmsvc_lock(struct svc_rqst rqstp, struct nlm_file file,
		struct nlm_lock lock, int wait, struct nlm_cookie cookie)
		{
		struct nlm_block *block;
		struct nlm_block block, newblock = NULL;
		int error;
		u32 ret;

		@@ -310,59 +310,65 @@ nlmsvc_lock(struct svc_rqst rqstp, struct nlm_file file,
		wait);


		/* Get existing block (in case client is busy-waiting) */
		block = nlmsvc_lookup_block(file, lock, 0);

		lock->fl.fl_flags &= ~FL_SLEEP;
		again:
		/* Lock file against concurrent access */
		down(&file->f_sema);
		/* Get existing block (in case client is busy-waiting) */
		block = nlmsvc_lookup_block(file, lock, 0);
		if (block == NULL) {
		if (newblock != NULL)
		lock = &newblock->b_call.a_args.lock.fl;
		} else
		lock = &block->b_call.a_args.lock.fl;

		error = posix_lock_file(file->f_file, &lock->fl);
		lock->fl.fl_flags &= ~FL_SLEEP;

		dprintk("lockd: posix_lock_file returned %d\n", error);

		if (error != -EAGAIN) {
		if (block)
		nlmsvc_delete_block(block, 0);
		up(&file->f_sema);

		switch(-error) {
		switch(error) {
		case 0:
		ret = nlm_granted;
		goto out;
		case EDEADLK:
		case -EAGAIN:
		break;
		case -EDEADLK:
		ret = nlm_deadlock;
		goto out;
		default: /* includes ENOLCK */
		ret = nlm_lck_denied_nolocks;
		goto out;
		}
		}

		if (!wait) {
		ret = nlm_lck_denied;
		goto out_unlock;
		}
		if (!wait)
		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_sema as nlmsvc_create_block may try to
		* to claim it while doing host garbage collection */
		if (block == NULL) {
		if (newblock == NULL) {
		up(&file->f_sema);
		dprintk("lockd: blocking on this lock (allocating).\n");
		if (!(block = nlmsvc_create_block(rqstp, file, lock, cookie)))
		if (!(newblock = nlmsvc_create_block(rqstp, file, lock, cookie)))
		return nlm_lck_denied_nolocks;
		goto again;
		}

		/* Append to list of blocked */
		nlmsvc_insert_block(block, NLM_NEVER);
		nlmsvc_insert_block(newblock, NLM_NEVER);
		newblock = NULL;

		ret = nlm_lck_blocked;
		out_unlock:
		up(&file->f_sema);
		out:
		up(&file->f_sema);
		if (newblock != NULL)
		nlmsvc_delete_block(newblock);
		dprintk("lockd: nlmsvc_lock returned %u\n", ret);
		return ret;
		}
		@@ -445,7 +451,7 @@ nlmsvc_cancel_blocked(struct nlm_file file, struct nlm_lock lock)

		down(&file->f_sema);
		if ((block = nlmsvc_lookup_block(file, lock, 1)) != NULL)
		status = nlmsvc_delete_block(block, 1);
		status = nlmsvc_delete_block(block);
		up(&file->f_sema);
		return status ? nlm_lck_denied : nlm_granted;
		}
		@@ -519,7 +525,11 @@ nlmsvc_grant_blocked(struct nlm_block *block)
		}

		/* Try the lock operation again */
		posix_unblock_lock(file->f_file, &lock->fl);
		lock->fl.fl_flags \|= FL_SLEEP;
		error = posix_lock_file(file->f_file, &lock->fl);
		lock->fl.fl_flags &= ~FL_SLEEP;

		switch (error) {
		case 0:
		break;
		@@ -630,11 +640,8 @@ nlmsvc_grant_reply(struct svc_rqst rqstp, struct nlm_cookie cookie, u32 status
		} else {
		/* Lock is now held by client, or has been rejected.
		* In both cases, the block should be removed. */
		nlmsvc_delete_block(block);
		up(&file->f_sema);
		if (status == NLM_LCK_GRANTED)
		nlmsvc_delete_block(block, 0);
		else
		nlmsvc_delete_block(block, 1);
		}
		}
		nlm_release_file(file);
		@@ -661,7 +668,7 @@ nlmsvc_retry_blocked(void)
		dprintk("nlmsvc_retry_blocked(%p, when=%ld, done=%d)\n",
		block, block->b_when, block->b_done);
		if (block->b_done)
		nlmsvc_delete_block(block, 0);
		nlmsvc_delete_block(block);
		else
		nlmsvc_grant_blocked(block);
		}