From 5c1c669a1b2435e071d566b6db1a8e6b26542ba1 Mon Sep 17 00:00:00 2001 From: Jeff Layton Date: Fri, 3 Apr 2015 09:04:03 -0400 Subject: [PATCH] locks: don't allocate a lock context for an F_UNLCK request In the event that we get an F_UNLCK request on an inode that has no lock context, there is no reason to allocate one. Change locks_get_lock_context to take a "type" pointer and avoid allocating a new context if it's F_UNLCK. Then, fix the callers to return appropriately if that function returns NULL. Signed-off-by: Jeff Layton --- fs/locks.c | 20 ++++++++++++-------- 1 file changed, 12 insertions(+), 8 deletions(-) diff --git a/fs/locks.c b/fs/locks.c index 36cf93f165a8..54a79883a7f9 100644 --- a/fs/locks.c +++ b/fs/locks.c @@ -203,11 +203,11 @@ static struct kmem_cache *flctx_cache __read_mostly; static struct kmem_cache *filelock_cache __read_mostly; static struct file_lock_context * -locks_get_lock_context(struct inode *inode) +locks_get_lock_context(struct inode *inode, int type) { struct file_lock_context *new; - if (likely(inode->i_flctx)) + if (likely(inode->i_flctx) || type == F_UNLCK) goto out; new = kmem_cache_alloc(flctx_cache, GFP_KERNEL); @@ -877,9 +877,12 @@ static int flock_lock_file(struct file *filp, struct file_lock *request) bool found = false; LIST_HEAD(dispose); - ctx = locks_get_lock_context(inode); - if (!ctx) - return -ENOMEM; + ctx = locks_get_lock_context(inode, request->fl_type); + if (!ctx) { + if (request->fl_type != F_UNLCK) + return -ENOMEM; + return (request->fl_flags & FL_EXISTS) ? -ENOENT : 0; + } if (!(request->fl_flags & FL_ACCESS) && (request->fl_type != F_UNLCK)) { new_fl = locks_alloc_lock(); @@ -945,9 +948,9 @@ static int __posix_lock_file(struct inode *inode, struct file_lock *request, str bool added = false; LIST_HEAD(dispose); - ctx = locks_get_lock_context(inode); + ctx = locks_get_lock_context(inode, request->fl_type); if (!ctx) - return -ENOMEM; + return (request->fl_type == F_UNLCK) ? 0 : -ENOMEM; /* * We may need two file_lock structures for this operation, @@ -1609,7 +1612,8 @@ generic_add_lease(struct file *filp, long arg, struct file_lock **flp, void **pr lease = *flp; trace_generic_add_lease(inode, lease); - ctx = locks_get_lock_context(inode); + /* Note that arg is never F_UNLCK here */ + ctx = locks_get_lock_context(inode, arg); if (!ctx) return -ENOMEM;