#include <linux/smp_lock.h>
#include <linux/syscalls.h>
#include <linux/time.h>
+#include <linux/rcupdate.h>
#include <asm/semaphore.h>
#include <asm/uaccess.h>
#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)
return kmem_cache_alloc(filelock_cache, SLAB_KERNEL);
}
-/* Free a lock which is not in use. */
-static inline void locks_free_lock(struct file_lock *fl)
+static void locks_release_private(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");
-
if (fl->fl_ops) {
if (fl->fl_ops->fl_release_private)
fl->fl_ops->fl_release_private(fl);
fl->fl_ops = NULL;
}
-
if (fl->fl_lmops) {
if (fl->fl_lmops->fl_release_private)
fl->fl_lmops->fl_release_private(fl);
fl->fl_lmops = NULL;
}
+}
+
+/* Free a lock which is not in use. */
+static void locks_free_lock(struct file_lock *fl)
+{
+ 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);
}
locks_init_lock(lock);
}
+static void locks_copy_private(struct file_lock *new, struct file_lock *fl)
+{
+ if (fl->fl_ops) {
+ if (fl->fl_ops->fl_copy_lock)
+ fl->fl_ops->fl_copy_lock(new, fl);
+ new->fl_ops = fl->fl_ops;
+ }
+ if (fl->fl_lmops) {
+ if (fl->fl_lmops->fl_copy_lock)
+ fl->fl_lmops->fl_copy_lock(new, fl);
+ new->fl_lmops = fl->fl_lmops;
+ }
+}
+
/*
* 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)
{
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;
- if (fl->fl_ops && fl->fl_ops->fl_copy_lock)
- fl->fl_ops->fl_copy_lock(new, fl);
- if (fl->fl_lmops && fl->fl_lmops->fl_copy_lock)
- fl->fl_lmops->fl_copy_lock(new, fl);
+
+ locks_copy_private(new, fl);
}
EXPORT_SYMBOL(locks_copy_lock);
/* POSIX-1996 leaves the case l->l_len < 0 undefined;
POSIX-2001 defines it. */
start += l->l_start;
- end = start + l->l_len - 1;
- if (l->l_len < 0) {
+ if (start < 0)
+ return -EINVAL;
+ fl->fl_end = OFFSET_MAX;
+ if (l->l_len > 0) {
+ end = start + l->l_len - 1;
+ fl->fl_end = end;
+ } else if (l->l_len < 0) {
end = start - 1;
+ fl->fl_end = end;
start += l->l_len;
+ if (start < 0)
+ return -EINVAL;
}
-
- if (start < 0)
- return -EINVAL;
- if (l->l_len > 0 && end < 0)
- return -EOVERFLOW;
-
fl->fl_start = start; /* we record the absolute position */
- fl->fl_end = end;
- if (l->l_len == 0)
- fl->fl_end = OFFSET_MAX;
+ if (fl->fl_end < fl->fl_start)
+ return -EOVERFLOW;
fl->fl_owner = current->files;
fl->fl_pid = current->tgid;
return -EINVAL;
}
- if (((start += l->l_start) < 0) || (l->l_len < 0))
+ start += l->l_start;
+ if (start < 0)
return -EINVAL;
- fl->fl_end = start + l->l_len - 1;
- if (l->l_len > 0 && fl->fl_end < 0)
- return -EOVERFLOW;
+ fl->fl_end = OFFSET_MAX;
+ if (l->l_len > 0) {
+ fl->fl_end = start + l->l_len - 1;
+ } else if (l->l_len < 0) {
+ fl->fl_end = start - 1;
+ start += l->l_len;
+ if (start < 0)
+ return -EINVAL;
+ }
fl->fl_start = start; /* we record the absolute position */
- if (l->l_len == 0)
- fl->fl_end = OFFSET_MAX;
+ if (fl->fl_end < fl->fl_start)
+ return -EOVERFLOW;
fl->fl_owner = current->files;
fl->fl_pid = current->tgid;
/*
* Check whether two locks have the same owner.
*/
-static inline int
-posix_same_owner(struct file_lock *fl1, struct file_lock *fl2)
+static int posix_same_owner(struct file_lock *fl1, struct file_lock *fl2)
{
if (fl1->fl_lmops && fl1->fl_lmops->fl_compare_owner)
return fl2->fl_lmops == fl1->fl_lmops &&
/* Remove waiter from blocker's block list.
* When blocker ends up pointing to itself then the list is empty.
*/
-static inline void __locks_delete_block(struct file_lock *waiter)
+static void __locks_delete_block(struct file_lock *waiter)
{
list_del_init(&waiter->fl_block);
list_del_init(&waiter->fl_link);
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;
+ 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);
- error = 0;
+ new_fl = NULL;
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;
/* Detect adjacent or overlapping regions (if same lock type)
*/
if (request->fl_type == fl->fl_type) {
+ /* In all comparisons of start vs end, use
+ * "start - 1" rather than "end + 1". If end
+ * is OFFSET_MAX, end + 1 will become negative.
+ */
if (fl->fl_end < request->fl_start - 1)
goto next_lock;
/* If the next lock in the list has entirely bigger
* addresses than the new one, insert the lock here.
*/
- if (fl->fl_start > request->fl_end + 1)
+ if (fl->fl_start - 1 > request->fl_end)
break;
/* If we come here, the new and old lock are of the
fl->fl_start = request->fl_start;
fl->fl_end = request->fl_end;
fl->fl_type = request->fl_type;
- fl->fl_u = request->fl_u;
+ locks_release_private(fl);
+ locks_copy_private(fl, request);
request = fl;
added = 1;
}
*/
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))
before = &fl->fl_next;
continue;
}
- printk(KERN_INFO "lease broken - owner pid = %d\n", fl->fl_pid);
lease_modify(before, fl->fl_type & ~F_INPROGRESS);
if (fl == *before) /* lease_modify may have freed fl */
before = &fl->fl_next;
lock_kernel();
error = __setlease(filp, arg, &flp);
- if (error)
+ if (error || arg == F_UNLCK)
goto out_unlock;
error = fasync_helper(fd, filp, 1, &flp->fl_fasync);
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,
unlock_kernel();
}
-/**
- * posix_block_lock - blocks waiting for a file lock
- * @blocker: the lock which is blocking
- * @waiter: the lock which conflicts and has to wait
- *
- * lockd needs to block waiting for locks.
- */
-void
-posix_block_lock(struct file_lock *blocker, struct file_lock *waiter)
-{
- locks_insert_block(blocker, waiter);
-}
-
-EXPORT_SYMBOL(posix_block_lock);
-
/**
* posix_unblock_lock - stop waiting for a file lock
* @filp: how the file was opened
*
* lockd needs to block waiting for locks.
*/
-void
+int
posix_unblock_lock(struct file *filp, struct file_lock *waiter)
{
- /*
- * A remote machine may cancel the lock request after it's been
- * granted locally. If that happens, we need to delete the lock.
- */
+ int status = 0;
+
lock_kernel();
- if (waiter->fl_next) {
+ if (waiter->fl_next)
__locks_delete_block(waiter);
- unlock_kernel();
- } else {
- unlock_kernel();
- waiter->fl_type = F_UNLCK;
- posix_lock_file(filp, waiter);
- }
+ else
+ status = -ENOENT;
+ unlock_kernel();
+ return status;
}
EXPORT_SYMBOL(posix_unblock_lock);
lock_kernel();
j = 0;
+ rcu_read_lock();
fdt = files_fdtable(files);
for (;;) {
unsigned long set;
set >>= 1;
}
}
+ rcu_read_unlock();
unlock_kernel();
}
EXPORT_SYMBOL(steal_locks);