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 <jlayton@primarydata.com>
This commit is contained in:
Jeff Layton 2015-04-03 09:04:03 -04:00
parent 663d5af750
commit 5c1c669a1b

View File

@ -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;