#define for_each_lock(inode, lockp) \
for (lockp = &inode->i_flock; *lockp != NULL; lockp = &(*lockp)->fl_next)
-LIST_HEAD(file_lock_list);
-
-EXPORT_SYMBOL(file_lock_list);
-
+static LIST_HEAD(file_lock_list);
static LIST_HEAD(blocked_list);
-static kmem_cache_t *filelock_cache;
+static kmem_cache_t *filelock_cache __read_mostly;
/* Allocate an empty lock structure. */
static struct file_lock *locks_alloc_lock(void)
/* Free a lock which is not in use. */
static void locks_free_lock(struct file_lock *fl)
{
- if (fl == NULL) {
- BUG();
- return;
- }
- if (waitqueue_active(&fl->fl_wait))
- panic("Attempting to free lock with active wait queue");
-
- if (!list_empty(&fl->fl_block))
- panic("Attempting to free lock with active block list");
-
- if (!list_empty(&fl->fl_link))
- panic("Attempting to free lock on active lock list");
+ BUG_ON(waitqueue_active(&fl->fl_wait));
+ BUG_ON(!list_empty(&fl->fl_block));
+ BUG_ON(!list_empty(&fl->fl_link));
locks_release_private(fl);
kmem_cache_free(filelock_cache, fl);
/*
* Initialize a new lock from an existing file_lock structure.
*/
-void locks_copy_lock(struct file_lock *new, struct file_lock *fl)
+static void __locks_copy_lock(struct file_lock *new, const struct file_lock *fl)
{
- locks_release_private(new);
-
new->fl_owner = fl->fl_owner;
new->fl_pid = fl->fl_pid;
- new->fl_file = fl->fl_file;
+ new->fl_file = NULL;
new->fl_flags = fl->fl_flags;
new->fl_type = fl->fl_type;
new->fl_start = fl->fl_start;
new->fl_end = fl->fl_end;
+ new->fl_ops = NULL;
+ new->fl_lmops = NULL;
+}
+
+void locks_copy_lock(struct file_lock *new, struct file_lock *fl)
+{
+ locks_release_private(new);
+
+ __locks_copy_lock(new, fl);
+ new->fl_file = fl->fl_file;
new->fl_ops = fl->fl_ops;
new->fl_lmops = fl->fl_lmops;
*/
static int lease_init(struct file *filp, int type, struct file_lock *fl)
{
+ if (assign_type(fl, type) != 0)
+ return -EINVAL;
+
fl->fl_owner = current->files;
fl->fl_pid = current->tgid;
fl->fl_file = filp;
fl->fl_flags = FL_LEASE;
- if (assign_type(fl, type) != 0) {
- locks_free_lock(fl);
- return -EINVAL;
- }
fl->fl_start = 0;
fl->fl_end = OFFSET_MAX;
fl->fl_ops = NULL;
static int lease_alloc(struct file *filp, int type, struct file_lock **flp)
{
struct file_lock *fl = locks_alloc_lock();
- int error;
+ int error = -ENOMEM;
if (fl == NULL)
- return -ENOMEM;
+ goto out;
error = lease_init(filp, type, fl);
- if (error)
- return error;
+ if (error) {
+ locks_free_lock(fl);
+ fl = NULL;
+ }
+out:
*flp = fl;
- return 0;
+ return error;
}
/* Check if two locks overlap each other.
static void locks_insert_block(struct file_lock *blocker,
struct file_lock *waiter)
{
- if (!list_empty(&waiter->fl_block)) {
- printk(KERN_ERR "locks_insert_block: removing duplicated lock "
- "(pid=%d %Ld-%Ld type=%d)\n", waiter->fl_pid,
- waiter->fl_start, waiter->fl_end, waiter->fl_type);
- __locks_delete_block(waiter);
- }
+ BUG_ON(!list_empty(&waiter->fl_block));
list_add_tail(&waiter->fl_block, &blocker->fl_block);
waiter->fl_next = blocker;
if (IS_POSIX(blocker))
return result;
}
-struct file_lock *
-posix_test_lock(struct file *filp, struct file_lock *fl)
+int
+posix_test_lock(struct file *filp, struct file_lock *fl,
+ struct file_lock *conflock)
{
struct file_lock *cfl;
if (posix_locks_conflict(cfl, fl))
break;
}
+ if (cfl) {
+ __locks_copy_lock(conflock, cfl);
+ unlock_kernel();
+ return 1;
+ }
unlock_kernel();
-
- return (cfl);
+ return 0;
}
EXPORT_SYMBOL(posix_test_lock);
* at the head of the list, but that's secret knowledge known only to
* flock_lock_file and posix_lock_file.
*/
-static int flock_lock_file(struct file *filp, struct file_lock *new_fl)
+static int flock_lock_file(struct file *filp, struct file_lock *request)
{
+ struct file_lock *new_fl = NULL;
struct file_lock **before;
struct inode * inode = filp->f_dentry->d_inode;
int error = 0;
continue;
if (filp != fl->fl_file)
continue;
- if (new_fl->fl_type == fl->fl_type)
+ if (request->fl_type == fl->fl_type)
goto out;
found = 1;
locks_delete_lock(before);
break;
}
- unlock_kernel();
- if (new_fl->fl_type == F_UNLCK)
- return 0;
+ if (request->fl_type == F_UNLCK)
+ goto out;
+ error = -ENOMEM;
+ new_fl = locks_alloc_lock();
+ if (new_fl == NULL)
+ goto out;
/*
* If a higher-priority process was blocked on the old file lock,
* give it the opportunity to lock the file.
if (found)
cond_resched();
- lock_kernel();
for_each_lock(inode, before) {
struct file_lock *fl = *before;
if (IS_POSIX(fl))
break;
if (IS_LEASE(fl))
continue;
- if (!flock_locks_conflict(new_fl, fl))
+ if (!flock_locks_conflict(request, fl))
continue;
error = -EAGAIN;
- if (new_fl->fl_flags & FL_SLEEP) {
- locks_insert_block(fl, new_fl);
- }
+ if (request->fl_flags & FL_SLEEP)
+ locks_insert_block(fl, request);
goto out;
}
+ locks_copy_lock(new_fl, request);
locks_insert_lock(&inode->i_flock, new_fl);
+ new_fl = NULL;
error = 0;
out:
unlock_kernel();
+ if (new_fl)
+ locks_free_lock(new_fl);
return error;
}
-EXPORT_SYMBOL(posix_lock_file);
-
-static int __posix_lock_file(struct inode *inode, struct file_lock *request)
+static int __posix_lock_file_conf(struct inode *inode, struct file_lock *request, struct file_lock *conflock)
{
struct file_lock *fl;
struct file_lock *new_fl, *new_fl2;
continue;
if (!posix_locks_conflict(request, fl))
continue;
+ if (conflock)
+ locks_copy_lock(conflock, fl);
error = -EAGAIN;
if (!(request->fl_flags & FL_SLEEP))
goto out;
*/
int posix_lock_file(struct file *filp, struct file_lock *fl)
{
- return __posix_lock_file(filp->f_dentry->d_inode, fl);
+ return __posix_lock_file_conf(filp->f_dentry->d_inode, fl, NULL);
+}
+EXPORT_SYMBOL(posix_lock_file);
+
+/**
+ * posix_lock_file_conf - Apply a POSIX-style lock to a file
+ * @filp: The file to apply the lock to
+ * @fl: The lock to be applied
+ * @conflock: Place to return a copy of the conflicting lock, if found.
+ *
+ * Except for the conflock parameter, acts just like posix_lock_file.
+ */
+int posix_lock_file_conf(struct file *filp, struct file_lock *fl,
+ struct file_lock *conflock)
+{
+ return __posix_lock_file_conf(filp->f_dentry->d_inode, fl, conflock);
}
+EXPORT_SYMBOL(posix_lock_file_conf);
/**
* posix_lock_file_wait - Apply a POSIX-style lock to a file
int error;
might_sleep ();
for (;;) {
- error = __posix_lock_file(filp->f_dentry->d_inode, fl);
+ error = posix_lock_file(filp, fl);
if ((error != -EAGAIN) || !(fl->fl_flags & FL_SLEEP))
break;
error = wait_event_interruptible(fl->fl_wait, !fl->fl_next);
fl.fl_end = offset + count - 1;
for (;;) {
- error = __posix_lock_file(inode, &fl);
+ error = __posix_lock_file_conf(inode, &fl, NULL);
if (error != -EAGAIN)
break;
if (!(fl.fl_flags & FL_SLEEP))
goto out;
if (my_before != NULL) {
+ *flp = *my_before;
error = lease->fl_lmops->fl_change(my_before, arg);
goto out;
}
error = flock_lock_file_wait(filp, lock);
out_free:
- if (list_empty(&lock->fl_link)) {
- locks_free_lock(lock);
- }
+ locks_free_lock(lock);
out_putf:
fput(filp);
*/
int fcntl_getlk(struct file *filp, struct flock __user *l)
{
- struct file_lock *fl, file_lock;
+ struct file_lock *fl, cfl, file_lock;
struct flock flock;
int error;
else
fl = (file_lock.fl_type == F_UNLCK ? NULL : &file_lock);
} else {
- fl = posix_test_lock(filp, &file_lock);
+ fl = (posix_test_lock(filp, &file_lock, &cfl) ? &cfl : NULL);
}
flock.l_type = F_UNLCK;
error = filp->f_op->lock(filp, cmd, file_lock);
else {
for (;;) {
- error = __posix_lock_file(inode, file_lock);
+ error = posix_lock_file(filp, file_lock);
if ((error != -EAGAIN) || (cmd == F_SETLK))
break;
error = wait_event_interruptible(file_lock->fl_wait,
*/
int fcntl_getlk64(struct file *filp, struct flock64 __user *l)
{
- struct file_lock *fl, file_lock;
+ struct file_lock *fl, cfl, file_lock;
struct flock64 flock;
int error;
else
fl = (file_lock.fl_type == F_UNLCK ? NULL : &file_lock);
} else {
- fl = posix_test_lock(filp, &file_lock);
+ fl = (posix_test_lock(filp, &file_lock, &cfl) ? &cfl : NULL);
}
flock.l_type = F_UNLCK;
error = filp->f_op->lock(filp, cmd, file_lock);
else {
for (;;) {
- error = __posix_lock_file(inode, file_lock);
+ error = posix_lock_file(filp, file_lock);
if ((error != -EAGAIN) || (cmd == F_SETLK64))
break;
error = wait_event_interruptible(file_lock->fl_wait,
lock_kernel();
j = 0;
- rcu_read_lock();
+
+ /*
+ * We are not taking a ref to the file structures, so
+ * we need to acquire ->file_lock.
+ */
+ spin_lock(&files->file_lock);
fdt = files_fdtable(files);
for (;;) {
unsigned long set;
set >>= 1;
}
}
- rcu_read_unlock();
+ spin_unlock(&files->file_lock);
unlock_kernel();
}
EXPORT_SYMBOL(steal_locks);