#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);
*/
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.
/*
* 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);
* from a broken NFS client. But broken NFS clients have a lot more to
* worry about than proper deadlock detection anyway... --okir
*/
-int posix_locks_deadlock(struct file_lock *caller_fl,
+static int posix_locks_deadlock(struct file_lock *caller_fl,
struct file_lock *block_fl)
{
struct list_head *tmp;
return 0;
}
-EXPORT_SYMBOL(posix_locks_deadlock);
-
/* Try to create a FLOCK lock on filp. We always insert new FLOCK locks
* at the head of the list, but that's secret knowledge known only to
* flock_lock_file and posix_lock_file.
+ *
+ * Note that if called with an FL_EXISTS argument, the caller may determine
+ * whether or not a lock was successfully freed by testing the return
+ * value for -ENOENT.
*/
-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;
int found = 0;
lock_kernel();
+ if (request->fl_flags & FL_ACCESS)
+ goto find_conflict;
for_each_lock(inode, before) {
struct file_lock *fl = *before;
if (IS_POSIX(fl))
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) {
+ if ((request->fl_flags & FL_EXISTS) && !found)
+ error = -ENOENT;
+ 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();
+find_conflict:
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;
}
+ if (request->fl_flags & FL_ACCESS)
+ 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;
+ struct file_lock *new_fl = NULL;
+ struct file_lock *new_fl2 = NULL;
struct file_lock *left = NULL;
struct file_lock *right = NULL;
struct file_lock **before;
/*
* We may need two file_lock structures for this operation,
* so we get them in advance to avoid races.
+ *
+ * In some cases we can be sure, that no new locks will be needed
*/
- new_fl = locks_alloc_lock();
- new_fl2 = locks_alloc_lock();
+ if (!(request->fl_flags & FL_ACCESS) &&
+ (request->fl_type != F_UNLCK ||
+ request->fl_start != 0 || request->fl_end != OFFSET_MAX)) {
+ new_fl = locks_alloc_lock();
+ new_fl2 = locks_alloc_lock();
+ }
lock_kernel();
if (request->fl_type != F_UNLCK) {
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;
if (request->fl_flags & FL_ACCESS)
goto out;
- error = -ENOLCK; /* "no luck" */
- if (!(new_fl && new_fl2))
- goto out;
-
/*
- * We've allocated the new locks in advance, so there are no
- * errors possible (and no blocking operations) from here on.
- *
* Find the first old lock with the same owner as the new lock.
*/
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;
}
before = &fl->fl_next;
}
+ /*
+ * The above code only modifies existing locks in case of
+ * merging or replacing. If new lock(s) need to be inserted
+ * all modifications are done bellow this, so it's safe yet to
+ * bail out.
+ */
+ error = -ENOLCK; /* "no luck" */
+ if (right && left == right && !new_fl2)
+ goto out;
+
error = 0;
if (!added) {
- if (request->fl_type == F_UNLCK)
+ if (request->fl_type == F_UNLCK) {
+ if (request->fl_flags & FL_EXISTS)
+ error = -ENOENT;
+ goto out;
+ }
+
+ if (!new_fl) {
+ error = -ENOLCK;
goto out;
+ }
locks_copy_lock(new_fl, request);
locks_insert_lock(before, new_fl);
new_fl = NULL;
* Add a POSIX style lock to a file.
* We merge adjacent & overlapping locks whenever possible.
* POSIX locks are sorted by owner task, then by starting address
+ *
+ * Note that if called with an FL_EXISTS argument, the caller may determine
+ * whether or not a lock was successfully freed by testing the return
+ * value for -ENOENT.
*/
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;
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,
*/
void locks_remove_posix(struct file *filp, fl_owner_t owner)
{
- struct file_lock lock, **before;
+ struct file_lock lock;
/*
* If there are no locks held on this file, we don't need to call
* posix_lock_file(). Another process could be setting a lock on this
* file at the same time, but we wouldn't remove that lock anyway.
*/
- before = &filp->f_dentry->d_inode->i_flock;
- if (*before == NULL)
+ if (!filp->f_dentry->d_inode->i_flock)
return;
lock.fl_type = F_UNLCK;
- lock.fl_flags = FL_POSIX;
+ lock.fl_flags = FL_POSIX | FL_CLOSE;
lock.fl_start = 0;
lock.fl_end = OFFSET_MAX;
lock.fl_owner = owner;
lock.fl_ops = NULL;
lock.fl_lmops = NULL;
- if (filp->f_op && filp->f_op->lock != NULL) {
+ if (filp->f_op && filp->f_op->lock != NULL)
filp->f_op->lock(filp, F_SETLK, &lock);
- goto out;
- }
+ else
+ posix_lock_file(filp, &lock);
- /* Can't use posix_lock_file here; we need to remove it no matter
- * which pid we have.
- */
- lock_kernel();
- while (*before != NULL) {
- struct file_lock *fl = *before;
- if (IS_POSIX(fl) && posix_same_owner(fl, &lock)) {
- locks_delete_lock(before);
- continue;
- }
- before = &fl->fl_next;
- }
- unlock_kernel();
-out:
if (lock.fl_ops && lock.fl_ops->fl_release_private)
lock.fl_ops->fl_release_private(&lock);
}
}
/**
- * 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
* @waiter: the lock which was waiting
*
* 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);
EXPORT_SYMBOL(lock_may_write);
-static inline void __steal_locks(struct file *file, fl_owner_t from)
-{
- struct inode *inode = file->f_dentry->d_inode;
- struct file_lock *fl = inode->i_flock;
-
- while (fl) {
- if (fl->fl_file == file && fl->fl_owner == from)
- fl->fl_owner = current->files;
- fl = fl->fl_next;
- }
-}
-
-/* When getting ready for executing a binary, we make sure that current
- * has a files_struct on its own. Before dropping the old files_struct,
- * we take over ownership of all locks for all file descriptors we own.
- * Note that we may accidentally steal a lock for a file that a sibling
- * has created since the unshare_files() call.
- */
-void steal_locks(fl_owner_t from)
-{
- struct files_struct *files = current->files;
- int i, j;
- struct fdtable *fdt;
-
- if (from == files)
- return;
-
- lock_kernel();
- j = 0;
- rcu_read_lock();
- fdt = files_fdtable(files);
- for (;;) {
- unsigned long set;
- i = j * __NFDBITS;
- if (i >= fdt->max_fdset || i >= fdt->max_fds)
- break;
- set = fdt->open_fds->fds_bits[j++];
- while (set) {
- if (set & 1) {
- struct file *file = fdt->fd[i];
- if (file)
- __steal_locks(file, from);
- }
- i++;
- set >>= 1;
- }
- }
- rcu_read_unlock();
- unlock_kernel();
-}
-EXPORT_SYMBOL(steal_locks);
-
static int __init filelock_init(void)
{
filelock_cache = kmem_cache_create("file_lock_cache",
git://ftp.safe.ca / safe / jmp / linux-2.6 / blobdiff