#include <linux/capability.h>
#include <linux/file.h>
+#include <linux/fdtable.h>
#include <linux/fs.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/syscalls.h>
#include <linux/time.h>
#include <linux/rcupdate.h>
+#include <linux/pid_namespace.h>
-#include <asm/semaphore.h>
#include <asm/uaccess.h>
#define IS_POSIX(fl) (fl->fl_flags & FL_POSIX)
return kmem_cache_alloc(filelock_cache, GFP_KERNEL);
}
-static void locks_release_private(struct file_lock *fl)
+void locks_release_private(struct file_lock *fl)
{
if (fl->fl_ops) {
if (fl->fl_ops->fl_release_private)
}
}
+EXPORT_SYMBOL_GPL(locks_release_private);
/* Free a lock which is not in use. */
static void locks_free_lock(struct file_lock *fl)
fl->fl_fasync = NULL;
fl->fl_owner = NULL;
fl->fl_pid = 0;
+ fl->fl_nspid = NULL;
fl->fl_file = NULL;
fl->fl_flags = 0;
fl->fl_type = 0;
* Initialises the fields of the file lock which are invariant for
* free file_locks.
*/
-static void init_once(void *foo, struct kmem_cache *cache, unsigned long flags)
+static void init_once(void *foo)
{
struct file_lock *lock = (struct file_lock *) foo;
- if ((flags & (SLAB_CTOR_VERIFY|SLAB_CTOR_CONSTRUCTOR)) !=
- SLAB_CTOR_CONSTRUCTOR)
- return;
-
locks_init_lock(lock);
}
/*
* Initialize a new lock from an existing file_lock structure.
*/
-static void __locks_copy_lock(struct file_lock *new, const struct file_lock *fl)
+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_ops = NULL;
new->fl_lmops = NULL;
}
+EXPORT_SYMBOL(__locks_copy_lock);
void locks_copy_lock(struct file_lock *new, struct file_lock *fl)
{
return fl->fl_file == try->fl_file;
}
-static struct lock_manager_operations lease_manager_ops = {
+static const struct lock_manager_operations lease_manager_ops = {
.fl_break = lease_break_callback,
.fl_release_private = lease_release_private_callback,
.fl_mylease = lease_mylease_callback,
}
/* Allocate a file_lock initialised to this type of lease */
-static int lease_alloc(struct file *filp, int type, struct file_lock **flp)
+static struct file_lock *lease_alloc(struct file *filp, int type)
{
struct file_lock *fl = locks_alloc_lock();
int error = -ENOMEM;
if (fl == NULL)
- goto out;
+ return ERR_PTR(error);
error = lease_init(filp, type, fl);
if (error) {
locks_free_lock(fl);
- fl = NULL;
+ return ERR_PTR(error);
}
-out:
- *flp = fl;
- return error;
+ return fl;
}
/* Check if two locks overlap each other.
static void locks_wake_up_blocks(struct file_lock *blocker)
{
while (!list_empty(&blocker->fl_block)) {
- struct file_lock *waiter = list_entry(blocker->fl_block.next,
+ struct file_lock *waiter;
+
+ waiter = list_first_entry(&blocker->fl_block,
struct file_lock, fl_block);
__locks_delete_block(waiter);
if (waiter->fl_lmops && waiter->fl_lmops->fl_notify)
{
list_add(&fl->fl_link, &file_lock_list);
+ fl->fl_nspid = get_pid(task_tgid(current));
+
/* insert into file's list */
fl->fl_next = *pos;
*pos = fl;
-
- if (fl->fl_ops && fl->fl_ops->fl_insert)
- fl->fl_ops->fl_insert(fl);
}
/*
fl->fl_fasync = NULL;
}
- if (fl->fl_ops && fl->fl_ops->fl_remove)
- fl->fl_ops->fl_remove(fl);
+ if (fl->fl_nspid) {
+ put_pid(fl->fl_nspid);
+ fl->fl_nspid = NULL;
+ }
locks_wake_up_blocks(fl);
locks_free_lock(fl);
return (locks_conflict(caller_fl, sys_fl));
}
-static int interruptible_sleep_on_locked(wait_queue_head_t *fl_wait, int timeout)
-{
- int result = 0;
- DECLARE_WAITQUEUE(wait, current);
-
- __set_current_state(TASK_INTERRUPTIBLE);
- add_wait_queue(fl_wait, &wait);
- if (timeout == 0)
- schedule();
- else
- result = schedule_timeout(timeout);
- if (signal_pending(current))
- result = -ERESTARTSYS;
- remove_wait_queue(fl_wait, &wait);
- __set_current_state(TASK_RUNNING);
- return result;
-}
-
-static int locks_block_on_timeout(struct file_lock *blocker, struct file_lock *waiter, int time)
-{
- int result;
- locks_insert_block(blocker, waiter);
- result = interruptible_sleep_on_locked(&waiter->fl_wait, time);
- __locks_delete_block(waiter);
- return result;
-}
-
-int
-posix_test_lock(struct file *filp, struct file_lock *fl,
- struct file_lock *conflock)
+void
+posix_test_lock(struct file *filp, struct file_lock *fl)
{
struct file_lock *cfl;
for (cfl = filp->f_path.dentry->d_inode->i_flock; cfl; cfl = cfl->fl_next) {
if (!IS_POSIX(cfl))
continue;
- if (posix_locks_conflict(cfl, fl))
+ if (posix_locks_conflict(fl, cfl))
break;
}
if (cfl) {
- __locks_copy_lock(conflock, cfl);
- unlock_kernel();
- return 1;
- }
+ __locks_copy_lock(fl, cfl);
+ if (cfl->fl_nspid)
+ fl->fl_pid = pid_vnr(cfl->fl_nspid);
+ } else
+ fl->fl_type = F_UNLCK;
unlock_kernel();
- return 0;
+ return;
}
-
EXPORT_SYMBOL(posix_test_lock);
-/* This function tests for deadlock condition before putting a process to
- * sleep. The detection scheme is no longer recursive. Recursive was neat,
- * but dangerous - we risked stack corruption if the lock data was bad, or
- * if the recursion was too deep for any other reason.
+/*
+ * Deadlock detection:
+ *
+ * We attempt to detect deadlocks that are due purely to posix file
+ * locks.
+ *
+ * We assume that a task can be waiting for at most one lock at a time.
+ * So for any acquired lock, the process holding that lock may be
+ * waiting on at most one other lock. That lock in turns may be held by
+ * someone waiting for at most one other lock. Given a requested lock
+ * caller_fl which is about to wait for a conflicting lock block_fl, we
+ * follow this chain of waiters to ensure we are not about to create a
+ * cycle.
*
- * We rely on the fact that a task can only be on one lock's wait queue
- * at a time. When we find blocked_task on a wait queue we can re-search
- * with blocked_task equal to that queue's owner, until either blocked_task
- * isn't found, or blocked_task is found on a queue owned by my_task.
+ * Since we do this before we ever put a process to sleep on a lock, we
+ * are ensured that there is never a cycle; that is what guarantees that
+ * the while() loop in posix_locks_deadlock() eventually completes.
*
- * Note: the above assumption may not be true when handling lock requests
- * from a broken NFS client. But broken NFS clients have a lot more to
- * worry about than proper deadlock detection anyway... --okir
+ * Note: the above assumption may not be true when handling lock
+ * requests from a broken NFS client. It may also fail in the presence
+ * of tasks (such as posix threads) sharing the same open file table.
+ *
+ * To handle those cases, we just bail out after a few iterations.
*/
+
+#define MAX_DEADLK_ITERATIONS 10
+
+/* Find a lock that the owner of the given block_fl is blocking on. */
+static struct file_lock *what_owner_is_waiting_for(struct file_lock *block_fl)
+{
+ struct file_lock *fl;
+
+ list_for_each_entry(fl, &blocked_list, fl_link) {
+ if (posix_same_owner(fl, block_fl))
+ return fl->fl_next;
+ }
+ return NULL;
+}
+
static int posix_locks_deadlock(struct file_lock *caller_fl,
struct file_lock *block_fl)
{
- struct list_head *tmp;
+ int i = 0;
-next_task:
- if (posix_same_owner(caller_fl, block_fl))
- return 1;
- list_for_each(tmp, &blocked_list) {
- struct file_lock *fl = list_entry(tmp, struct file_lock, fl_link);
- if (posix_same_owner(fl, block_fl)) {
- fl = fl->fl_next;
- block_fl = fl;
- goto next_task;
- }
+ while ((block_fl = what_owner_is_waiting_for(block_fl))) {
+ if (i++ > MAX_DEADLK_ITERATIONS)
+ return 0;
+ if (posix_same_owner(caller_fl, block_fl))
+ return 1;
}
return 0;
}
/* 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.
+ * after any leases, but before any posix locks.
*
* 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
lock_kernel();
if (request->fl_flags & FL_ACCESS)
goto find_conflict;
+
+ if (request->fl_type != F_UNLCK) {
+ error = -ENOMEM;
+ new_fl = locks_alloc_lock();
+ if (new_fl == NULL)
+ goto out;
+ error = 0;
+ }
+
for_each_lock(inode, before) {
struct file_lock *fl = *before;
if (IS_POSIX(fl))
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 (!flock_locks_conflict(request, fl))
continue;
error = -EAGAIN;
- if (request->fl_flags & FL_SLEEP)
- locks_insert_block(fl, request);
+ if (!(request->fl_flags & FL_SLEEP))
+ goto out;
+ error = FILE_LOCK_DEFERRED;
+ 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);
+ locks_insert_lock(before, new_fl);
new_fl = NULL;
error = 0;
return error;
}
-static int __posix_lock_file_conf(struct inode *inode, struct file_lock *request, struct file_lock *conflock)
+static int __posix_lock_file(struct inode *inode, struct file_lock *request, struct file_lock *conflock)
{
struct file_lock *fl;
struct file_lock *new_fl = NULL;
lock_kernel();
if (request->fl_type != F_UNLCK) {
for_each_lock(inode, before) {
- struct file_lock *fl = *before;
+ fl = *before;
if (!IS_POSIX(fl))
continue;
if (!posix_locks_conflict(request, fl))
continue;
if (conflock)
- locks_copy_lock(conflock, fl);
+ __locks_copy_lock(conflock, fl);
error = -EAGAIN;
if (!(request->fl_flags & FL_SLEEP))
goto out;
error = -EDEADLK;
if (posix_locks_deadlock(request, fl))
goto out;
- error = -EAGAIN;
+ error = FILE_LOCK_DEFERRED;
locks_insert_block(fl, request);
goto out;
}
* posix_lock_file - 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.
*
* Add a POSIX style lock to a file.
* We merge adjacent & overlapping locks whenever possible.
* 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_conf(filp->f_path.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,
+int posix_lock_file(struct file *filp, struct file_lock *fl,
struct file_lock *conflock)
{
- return __posix_lock_file_conf(filp->f_path.dentry->d_inode, fl, conflock);
+ return __posix_lock_file(filp->f_path.dentry->d_inode, fl, conflock);
}
-EXPORT_SYMBOL(posix_lock_file_conf);
+EXPORT_SYMBOL(posix_lock_file);
/**
* posix_lock_file_wait - Apply a POSIX-style lock to a file
int error;
might_sleep ();
for (;;) {
- error = posix_lock_file(filp, fl);
- if ((error != -EAGAIN) || !(fl->fl_flags & FL_SLEEP))
+ error = posix_lock_file(filp, fl, NULL);
+ if (error != FILE_LOCK_DEFERRED)
break;
error = wait_event_interruptible(fl->fl_wait, !fl->fl_next);
if (!error)
fl.fl_end = offset + count - 1;
for (;;) {
- error = __posix_lock_file_conf(inode, &fl, NULL);
- if (error != -EAGAIN)
- break;
- if (!(fl.fl_flags & FL_SLEEP))
+ error = __posix_lock_file(inode, &fl, NULL);
+ if (error != FILE_LOCK_DEFERRED)
break;
error = wait_event_interruptible(fl.fl_wait, !fl.fl_next);
if (!error) {
* If we've been sleeping someone might have
* changed the permissions behind our back.
*/
- if ((inode->i_mode & (S_ISGID | S_IXGRP)) == S_ISGID)
+ if (__mandatory_lock(inode))
continue;
}
* @inode: the inode of the file to return
* @mode: the open mode (read or write)
*
- * break_lease (inlined for speed) has checked there already
- * is a lease on this file. Leases are broken on a call to open()
- * or truncate(). This function can sleep unless you
+ * break_lease (inlined for speed) has checked there already is at least
+ * some kind of lock (maybe a lease) on this file. Leases are broken on
+ * a call to open() or truncate(). This function can sleep unless you
* specified %O_NONBLOCK to your open().
*/
int __break_lease(struct inode *inode, unsigned int mode)
int error = 0, future;
struct file_lock *new_fl, *flock;
struct file_lock *fl;
- int alloc_err;
unsigned long break_time;
int i_have_this_lease = 0;
- alloc_err = lease_alloc(NULL, mode & FMODE_WRITE ? F_WRLCK : F_RDLCK,
- &new_fl);
+ new_fl = lease_alloc(NULL, mode & FMODE_WRITE ? F_WRLCK : F_RDLCK);
lock_kernel();
goto out;
}
- if (alloc_err && !i_have_this_lease && ((mode & O_NONBLOCK) == 0)) {
- error = alloc_err;
+ if (IS_ERR(new_fl) && !i_have_this_lease
+ && ((mode & O_NONBLOCK) == 0)) {
+ error = PTR_ERR(new_fl);
goto out;
}
if (break_time == 0)
break_time++;
}
- error = locks_block_on_timeout(flock, new_fl, break_time);
+ locks_insert_block(flock, new_fl);
+ error = wait_event_interruptible_timeout(new_fl->fl_wait,
+ !new_fl->fl_next, break_time);
+ __locks_delete_block(new_fl);
if (error >= 0) {
if (error == 0)
time_out_leases(inode);
out:
unlock_kernel();
- if (!alloc_err)
+ if (!IS_ERR(new_fl))
locks_free_lock(new_fl);
return error;
}
EXPORT_SYMBOL(__break_lease);
/**
- * lease_get_mtime
+ * lease_get_mtime - get the last modified time of an inode
* @inode: the inode
* @time: pointer to a timespec which will contain the last modified time
*
* This is to force NFS clients to flush their caches for files with
* exclusive leases. The justification is that if someone has an
- * exclusive lease, then they could be modifiying it.
+ * exclusive lease, then they could be modifying it.
*/
void lease_get_mtime(struct inode *inode, struct timespec *time)
{
}
/**
- * __setlease - sets a lease on an open file
+ * generic_setlease - sets a lease on an open file
* @filp: file pointer
* @arg: type of lease to obtain
* @flp: input - file_lock to use, output - file_lock inserted
*
* Called with kernel lock held.
*/
-static int __setlease(struct file *filp, long arg, struct file_lock **flp)
+int generic_setlease(struct file *filp, long arg, struct file_lock **flp)
{
struct file_lock *fl, **before, **my_before = NULL, *lease;
+ struct file_lock *new_fl = NULL;
struct dentry *dentry = filp->f_path.dentry;
struct inode *inode = dentry->d_inode;
int error, rdlease_count = 0, wrlease_count = 0;
+ if ((current_fsuid() != inode->i_uid) && !capable(CAP_LEASE))
+ return -EACCES;
+ if (!S_ISREG(inode->i_mode))
+ return -EINVAL;
+ error = security_file_lock(filp, arg);
+ if (error)
+ return error;
+
time_out_leases(inode);
- error = -EINVAL;
- if (!flp || !(*flp) || !(*flp)->fl_lmops || !(*flp)->fl_lmops->fl_break)
- goto out;
+ BUG_ON(!(*flp)->fl_lmops->fl_break);
lease = *flp;
- error = -EAGAIN;
- if ((arg == F_RDLCK) && (atomic_read(&inode->i_writecount) > 0))
- goto out;
- if ((arg == F_WRLCK)
- && ((atomic_read(&dentry->d_count) > 1)
- || (atomic_read(&inode->i_count) > 1)))
- goto out;
+ if (arg != F_UNLCK) {
+ error = -ENOMEM;
+ new_fl = locks_alloc_lock();
+ if (new_fl == NULL)
+ goto out;
+
+ error = -EAGAIN;
+ if ((arg == F_RDLCK) && (atomic_read(&inode->i_writecount) > 0))
+ goto out;
+ if ((arg == F_WRLCK)
+ && ((atomic_read(&dentry->d_count) > 1)
+ || (atomic_read(&inode->i_count) > 1)))
+ goto out;
+ }
/*
* At this point, we know that if there is an exclusive
rdlease_count++;
}
+ error = -EAGAIN;
if ((arg == F_RDLCK && (wrlease_count > 0)) ||
(arg == F_WRLCK && ((rdlease_count + wrlease_count) > 0)))
goto out;
if (!leases_enable)
goto out;
- error = -ENOMEM;
- fl = locks_alloc_lock();
- if (fl == NULL)
- goto out;
-
- locks_copy_lock(fl, lease);
+ locks_copy_lock(new_fl, lease);
+ locks_insert_lock(before, new_fl);
- locks_insert_lock(before, fl);
+ *flp = new_fl;
+ return 0;
- *flp = fl;
- error = 0;
out:
+ if (new_fl != NULL)
+ locks_free_lock(new_fl);
return error;
}
+EXPORT_SYMBOL(generic_setlease);
/**
- * setlease - sets a lease on an open file
+ * vfs_setlease - sets a lease on an open file
* @filp: file pointer
* @arg: type of lease to obtain
* @lease: file_lock to use
*
* Call this to establish a lease on the file.
- * The fl_lmops fl_break function is required by break_lease
+ * The (*lease)->fl_lmops->fl_break operation must be set; if not,
+ * break_lease will oops!
+ *
+ * This will call the filesystem's setlease file method, if
+ * defined. Note that there is no getlease method; instead, the
+ * filesystem setlease method should call back to setlease() to
+ * add a lease to the inode's lease list, where fcntl_getlease() can
+ * find it. Since fcntl_getlease() only reports whether the current
+ * task holds a lease, a cluster filesystem need only do this for
+ * leases held by processes on this node.
+ *
+ * There is also no break_lease method; filesystems that
+ * handle their own leases shoud break leases themselves from the
+ * filesystem's open, create, and (on truncate) setattr methods.
+ *
+ * Warning: the only current setlease methods exist only to disable
+ * leases in certain cases. More vfs changes may be required to
+ * allow a full filesystem lease implementation.
*/
-int setlease(struct file *filp, long arg, struct file_lock **lease)
+int vfs_setlease(struct file *filp, long arg, struct file_lock **lease)
{
- struct dentry *dentry = filp->f_path.dentry;
- struct inode *inode = dentry->d_inode;
int error;
- if ((current->fsuid != inode->i_uid) && !capable(CAP_LEASE))
- return -EACCES;
- if (!S_ISREG(inode->i_mode))
- return -EINVAL;
- error = security_file_lock(filp, arg);
- if (error)
- return error;
-
lock_kernel();
- error = __setlease(filp, arg, lease);
+ if (filp->f_op && filp->f_op->setlease)
+ error = filp->f_op->setlease(filp, arg, lease);
+ else
+ error = generic_setlease(filp, arg, lease);
unlock_kernel();
return error;
}
-
-EXPORT_SYMBOL(setlease);
+EXPORT_SYMBOL_GPL(vfs_setlease);
/**
* fcntl_setlease - sets a lease on an open file
int fcntl_setlease(unsigned int fd, struct file *filp, long arg)
{
struct file_lock fl, *flp = &fl;
- struct dentry *dentry = filp->f_path.dentry;
- struct inode *inode = dentry->d_inode;
+ struct inode *inode = filp->f_path.dentry->d_inode;
int error;
- if ((current->fsuid != inode->i_uid) && !capable(CAP_LEASE))
- return -EACCES;
- if (!S_ISREG(inode->i_mode))
- return -EINVAL;
- error = security_file_lock(filp, arg);
- if (error)
- return error;
-
locks_init_lock(&fl);
error = lease_init(filp, arg, &fl);
if (error)
lock_kernel();
- error = __setlease(filp, arg, &flp);
+ error = vfs_setlease(filp, arg, &flp);
if (error || arg == F_UNLCK)
goto out_unlock;
error = fasync_helper(fd, filp, 1, &flp->fl_fasync);
if (error < 0) {
- /* remove lease just inserted by __setlease */
+ /* remove lease just inserted by setlease */
flp->fl_type = F_UNLCK | F_INPROGRESS;
- flp->fl_break_time = jiffies- 10;
+ flp->fl_break_time = jiffies - 10;
time_out_leases(inode);
goto out_unlock;
}
might_sleep();
for (;;) {
error = flock_lock_file(filp, fl);
- if ((error != -EAGAIN) || !(fl->fl_flags & FL_SLEEP))
+ if (error != FILE_LOCK_DEFERRED)
break;
error = wait_event_interruptible(fl->fl_wait, !fl->fl_next);
if (!error)
* %LOCK_MAND can be combined with %LOCK_READ or %LOCK_WRITE to allow other
* processes read and write access respectively.
*/
-asmlinkage long sys_flock(unsigned int fd, unsigned int cmd)
+SYSCALL_DEFINE2(flock, unsigned int, fd, unsigned int, cmd)
{
struct file *filp;
struct file_lock *lock;
cmd &= ~LOCK_NB;
unlock = (cmd == LOCK_UN);
- if (!unlock && !(cmd & LOCK_MAND) && !(filp->f_mode & 3))
+ if (!unlock && !(cmd & LOCK_MAND) &&
+ !(filp->f_mode & (FMODE_READ|FMODE_WRITE)))
goto out_putf;
error = flock_make_lock(filp, &lock, cmd);
if (can_sleep)
lock->fl_flags |= FL_SLEEP;
- error = security_file_lock(filp, cmd);
+ error = security_file_lock(filp, lock->fl_type);
if (error)
goto out_free;
return error;
}
+/**
+ * vfs_test_lock - test file byte range lock
+ * @filp: The file to test lock for
+ * @fl: The lock to test; also used to hold result
+ *
+ * Returns -ERRNO on failure. Indicates presence of conflicting lock by
+ * setting conf->fl_type to something other than F_UNLCK.
+ */
+int vfs_test_lock(struct file *filp, struct file_lock *fl)
+{
+ if (filp->f_op && filp->f_op->lock)
+ return filp->f_op->lock(filp, F_GETLK, fl);
+ posix_test_lock(filp, fl);
+ return 0;
+}
+EXPORT_SYMBOL_GPL(vfs_test_lock);
+
+static int posix_lock_to_flock(struct flock *flock, struct file_lock *fl)
+{
+ flock->l_pid = fl->fl_pid;
+#if BITS_PER_LONG == 32
+ /*
+ * Make sure we can represent the posix lock via
+ * legacy 32bit flock.
+ */
+ if (fl->fl_start > OFFT_OFFSET_MAX)
+ return -EOVERFLOW;
+ if (fl->fl_end != OFFSET_MAX && fl->fl_end > OFFT_OFFSET_MAX)
+ return -EOVERFLOW;
+#endif
+ flock->l_start = fl->fl_start;
+ flock->l_len = fl->fl_end == OFFSET_MAX ? 0 :
+ fl->fl_end - fl->fl_start + 1;
+ flock->l_whence = 0;
+ flock->l_type = fl->fl_type;
+ return 0;
+}
+
+#if BITS_PER_LONG == 32
+static void posix_lock_to_flock64(struct flock64 *flock, struct file_lock *fl)
+{
+ flock->l_pid = fl->fl_pid;
+ flock->l_start = fl->fl_start;
+ flock->l_len = fl->fl_end == OFFSET_MAX ? 0 :
+ fl->fl_end - fl->fl_start + 1;
+ flock->l_whence = 0;
+ flock->l_type = fl->fl_type;
+}
+#endif
+
/* Report the first existing lock that would conflict with l.
* This implements the F_GETLK command of fcntl().
*/
int fcntl_getlk(struct file *filp, struct flock __user *l)
{
- struct file_lock *fl, cfl, file_lock;
+ struct file_lock file_lock;
struct flock flock;
int error;
if (error)
goto out;
- if (filp->f_op && filp->f_op->lock) {
- error = filp->f_op->lock(filp, F_GETLK, &file_lock);
- if (file_lock.fl_ops && file_lock.fl_ops->fl_release_private)
- file_lock.fl_ops->fl_release_private(&file_lock);
- if (error < 0)
- goto out;
- else
- fl = (file_lock.fl_type == F_UNLCK ? NULL : &file_lock);
- } else {
- fl = (posix_test_lock(filp, &file_lock, &cfl) ? &cfl : NULL);
- }
+ error = vfs_test_lock(filp, &file_lock);
+ if (error)
+ goto out;
- flock.l_type = F_UNLCK;
- if (fl != NULL) {
- flock.l_pid = fl->fl_pid;
-#if BITS_PER_LONG == 32
- /*
- * Make sure we can represent the posix lock via
- * legacy 32bit flock.
- */
- error = -EOVERFLOW;
- if (fl->fl_start > OFFT_OFFSET_MAX)
- goto out;
- if ((fl->fl_end != OFFSET_MAX)
- && (fl->fl_end > OFFT_OFFSET_MAX))
+ flock.l_type = file_lock.fl_type;
+ if (file_lock.fl_type != F_UNLCK) {
+ error = posix_lock_to_flock(&flock, &file_lock);
+ if (error)
goto out;
-#endif
- flock.l_start = fl->fl_start;
- flock.l_len = fl->fl_end == OFFSET_MAX ? 0 :
- fl->fl_end - fl->fl_start + 1;
- flock.l_whence = 0;
- flock.l_type = fl->fl_type;
}
error = -EFAULT;
if (!copy_to_user(l, &flock, sizeof(flock)))
return error;
}
+/**
+ * vfs_lock_file - file byte range lock
+ * @filp: The file to apply the lock to
+ * @cmd: type of locking operation (F_SETLK, F_GETLK, etc.)
+ * @fl: The lock to be applied
+ * @conf: Place to return a copy of the conflicting lock, if found.
+ *
+ * A caller that doesn't care about the conflicting lock may pass NULL
+ * as the final argument.
+ *
+ * If the filesystem defines a private ->lock() method, then @conf will
+ * be left unchanged; so a caller that cares should initialize it to
+ * some acceptable default.
+ *
+ * To avoid blocking kernel daemons, such as lockd, that need to acquire POSIX
+ * locks, the ->lock() interface may return asynchronously, before the lock has
+ * been granted or denied by the underlying filesystem, if (and only if)
+ * fl_grant is set. Callers expecting ->lock() to return asynchronously
+ * will only use F_SETLK, not F_SETLKW; they will set FL_SLEEP if (and only if)
+ * the request is for a blocking lock. When ->lock() does return asynchronously,
+ * it must return FILE_LOCK_DEFERRED, and call ->fl_grant() when the lock
+ * request completes.
+ * If the request is for non-blocking lock the file system should return
+ * FILE_LOCK_DEFERRED then try to get the lock and call the callback routine
+ * with the result. If the request timed out the callback routine will return a
+ * nonzero return code and the file system should release the lock. The file
+ * system is also responsible to keep a corresponding posix lock when it
+ * grants a lock so the VFS can find out which locks are locally held and do
+ * the correct lock cleanup when required.
+ * The underlying filesystem must not drop the kernel lock or call
+ * ->fl_grant() before returning to the caller with a FILE_LOCK_DEFERRED
+ * return code.
+ */
+int vfs_lock_file(struct file *filp, unsigned int cmd, struct file_lock *fl, struct file_lock *conf)
+{
+ if (filp->f_op && filp->f_op->lock)
+ return filp->f_op->lock(filp, cmd, fl);
+ else
+ return posix_lock_file(filp, fl, conf);
+}
+EXPORT_SYMBOL_GPL(vfs_lock_file);
+
+static int do_lock_file_wait(struct file *filp, unsigned int cmd,
+ struct file_lock *fl)
+{
+ int error;
+
+ error = security_file_lock(filp, fl->fl_type);
+ if (error)
+ return error;
+
+ for (;;) {
+ error = vfs_lock_file(filp, cmd, fl, NULL);
+ if (error != FILE_LOCK_DEFERRED)
+ break;
+ error = wait_event_interruptible(fl->fl_wait, !fl->fl_next);
+ if (!error)
+ continue;
+
+ locks_delete_block(fl);
+ break;
+ }
+
+ return error;
+}
+
/* Apply the lock described by l to an open file descriptor.
* This implements both the F_SETLK and F_SETLKW commands of fcntl().
*/
struct file_lock *file_lock = locks_alloc_lock();
struct flock flock;
struct inode *inode;
+ struct file *f;
int error;
if (file_lock == NULL)
/* Don't allow mandatory locks on files that may be memory mapped
* and shared.
*/
- if (IS_MANDLOCK(inode) &&
- (inode->i_mode & (S_ISGID | S_IXGRP)) == S_ISGID &&
- mapping_writably_mapped(filp->f_mapping)) {
+ if (mandatory_lock(inode) && mapping_writably_mapped(filp->f_mapping)) {
error = -EAGAIN;
goto out;
}
goto out;
}
- error = security_file_lock(filp, file_lock->fl_type);
- if (error)
- goto out;
-
- if (filp->f_op && filp->f_op->lock != NULL)
- error = filp->f_op->lock(filp, cmd, file_lock);
- else {
- for (;;) {
- error = posix_lock_file(filp, file_lock);
- if ((error != -EAGAIN) || (cmd == F_SETLK))
- break;
- error = wait_event_interruptible(file_lock->fl_wait,
- !file_lock->fl_next);
- if (!error)
- continue;
-
- locks_delete_block(file_lock);
- break;
- }
- }
+ error = do_lock_file_wait(filp, cmd, file_lock);
/*
* Attempt to detect a close/fcntl race and recover by
* releasing the lock that was just acquired.
*/
- if (!error && fcheck(fd) != filp && flock.l_type != F_UNLCK) {
+ /*
+ * we need that spin_lock here - it prevents reordering between
+ * update of inode->i_flock and check for it done in close().
+ * rcu_read_lock() wouldn't do.
+ */
+ spin_lock(¤t->files->file_lock);
+ f = fcheck(fd);
+ spin_unlock(¤t->files->file_lock);
+ if (!error && f != filp && flock.l_type != F_UNLCK) {
flock.l_type = F_UNLCK;
goto again;
}
*/
int fcntl_getlk64(struct file *filp, struct flock64 __user *l)
{
- struct file_lock *fl, cfl, file_lock;
+ struct file_lock file_lock;
struct flock64 flock;
int error;
if (error)
goto out;
- if (filp->f_op && filp->f_op->lock) {
- error = filp->f_op->lock(filp, F_GETLK, &file_lock);
- if (file_lock.fl_ops && file_lock.fl_ops->fl_release_private)
- file_lock.fl_ops->fl_release_private(&file_lock);
- if (error < 0)
- goto out;
- else
- fl = (file_lock.fl_type == F_UNLCK ? NULL : &file_lock);
- } else {
- fl = (posix_test_lock(filp, &file_lock, &cfl) ? &cfl : NULL);
- }
-
- flock.l_type = F_UNLCK;
- if (fl != NULL) {
- flock.l_pid = fl->fl_pid;
- flock.l_start = fl->fl_start;
- flock.l_len = fl->fl_end == OFFSET_MAX ? 0 :
- fl->fl_end - fl->fl_start + 1;
- flock.l_whence = 0;
- flock.l_type = fl->fl_type;
- }
+ error = vfs_test_lock(filp, &file_lock);
+ if (error)
+ goto out;
+
+ flock.l_type = file_lock.fl_type;
+ if (file_lock.fl_type != F_UNLCK)
+ posix_lock_to_flock64(&flock, &file_lock);
+
error = -EFAULT;
if (!copy_to_user(l, &flock, sizeof(flock)))
error = 0;
struct file_lock *file_lock = locks_alloc_lock();
struct flock64 flock;
struct inode *inode;
+ struct file *f;
int error;
if (file_lock == NULL)
/* Don't allow mandatory locks on files that may be memory mapped
* and shared.
*/
- if (IS_MANDLOCK(inode) &&
- (inode->i_mode & (S_ISGID | S_IXGRP)) == S_ISGID &&
- mapping_writably_mapped(filp->f_mapping)) {
+ if (mandatory_lock(inode) && mapping_writably_mapped(filp->f_mapping)) {
error = -EAGAIN;
goto out;
}
goto out;
}
- error = security_file_lock(filp, file_lock->fl_type);
- if (error)
- goto out;
-
- if (filp->f_op && filp->f_op->lock != NULL)
- error = filp->f_op->lock(filp, cmd, file_lock);
- else {
- for (;;) {
- error = posix_lock_file(filp, file_lock);
- if ((error != -EAGAIN) || (cmd == F_SETLK64))
- break;
- error = wait_event_interruptible(file_lock->fl_wait,
- !file_lock->fl_next);
- if (!error)
- continue;
-
- locks_delete_block(file_lock);
- break;
- }
- }
+ error = do_lock_file_wait(filp, cmd, file_lock);
/*
* Attempt to detect a close/fcntl race and recover by
* releasing the lock that was just acquired.
*/
- if (!error && fcheck(fd) != filp && flock.l_type != F_UNLCK) {
+ spin_lock(¤t->files->file_lock);
+ f = fcheck(fd);
+ spin_unlock(¤t->files->file_lock);
+ if (!error && f != filp && flock.l_type != F_UNLCK) {
flock.l_type = F_UNLCK;
goto again;
}
lock.fl_ops = NULL;
lock.fl_lmops = NULL;
- if (filp->f_op && filp->f_op->lock != NULL)
- filp->f_op->lock(filp, F_SETLK, &lock);
- else
- posix_lock_file(filp, &lock);
+ vfs_lock_file(filp, F_SETLK, &lock, NULL);
if (lock.fl_ops && lock.fl_ops->fl_release_private)
lock.fl_ops->fl_release_private(&lock);
EXPORT_SYMBOL(posix_unblock_lock);
-static void lock_get_status(char* out, struct file_lock *fl, int id, char *pfx)
+/**
+ * vfs_cancel_lock - file byte range unblock lock
+ * @filp: The file to apply the unblock to
+ * @fl: The lock to be unblocked
+ *
+ * Used by lock managers to cancel blocked requests
+ */
+int vfs_cancel_lock(struct file *filp, struct file_lock *fl)
+{
+ if (filp->f_op && filp->f_op->lock)
+ return filp->f_op->lock(filp, F_CANCELLK, fl);
+ return 0;
+}
+
+EXPORT_SYMBOL_GPL(vfs_cancel_lock);
+
+#ifdef CONFIG_PROC_FS
+#include <linux/proc_fs.h>
+#include <linux/seq_file.h>
+
+static void lock_get_status(struct seq_file *f, struct file_lock *fl,
+ int id, char *pfx)
{
struct inode *inode = NULL;
+ unsigned int fl_pid;
+
+ if (fl->fl_nspid)
+ fl_pid = pid_vnr(fl->fl_nspid);
+ else
+ fl_pid = fl->fl_pid;
if (fl->fl_file != NULL)
inode = fl->fl_file->f_path.dentry->d_inode;
- out += sprintf(out, "%d:%s ", id, pfx);
+ seq_printf(f, "%d:%s ", id, pfx);
if (IS_POSIX(fl)) {
- out += sprintf(out, "%6s %s ",
+ seq_printf(f, "%6s %s ",
(fl->fl_flags & FL_ACCESS) ? "ACCESS" : "POSIX ",
(inode == NULL) ? "*NOINODE*" :
- (IS_MANDLOCK(inode) &&
- (inode->i_mode & (S_IXGRP | S_ISGID)) == S_ISGID) ?
- "MANDATORY" : "ADVISORY ");
+ mandatory_lock(inode) ? "MANDATORY" : "ADVISORY ");
} else if (IS_FLOCK(fl)) {
if (fl->fl_type & LOCK_MAND) {
- out += sprintf(out, "FLOCK MSNFS ");
+ seq_printf(f, "FLOCK MSNFS ");
} else {
- out += sprintf(out, "FLOCK ADVISORY ");
+ seq_printf(f, "FLOCK ADVISORY ");
}
} else if (IS_LEASE(fl)) {
- out += sprintf(out, "LEASE ");
+ seq_printf(f, "LEASE ");
if (fl->fl_type & F_INPROGRESS)
- out += sprintf(out, "BREAKING ");
+ seq_printf(f, "BREAKING ");
else if (fl->fl_file)
- out += sprintf(out, "ACTIVE ");
+ seq_printf(f, "ACTIVE ");
else
- out += sprintf(out, "BREAKER ");
+ seq_printf(f, "BREAKER ");
} else {
- out += sprintf(out, "UNKNOWN UNKNOWN ");
+ seq_printf(f, "UNKNOWN UNKNOWN ");
}
if (fl->fl_type & LOCK_MAND) {
- out += sprintf(out, "%s ",
+ seq_printf(f, "%s ",
(fl->fl_type & LOCK_READ)
? (fl->fl_type & LOCK_WRITE) ? "RW " : "READ "
: (fl->fl_type & LOCK_WRITE) ? "WRITE" : "NONE ");
} else {
- out += sprintf(out, "%s ",
+ seq_printf(f, "%s ",
(fl->fl_type & F_INPROGRESS)
? (fl->fl_type & F_UNLCK) ? "UNLCK" : "READ "
: (fl->fl_type & F_WRLCK) ? "WRITE" : "READ ");
}
if (inode) {
#ifdef WE_CAN_BREAK_LSLK_NOW
- out += sprintf(out, "%d %s:%ld ", fl->fl_pid,
+ seq_printf(f, "%d %s:%ld ", fl_pid,
inode->i_sb->s_id, inode->i_ino);
#else
/* userspace relies on this representation of dev_t ;-( */
- out += sprintf(out, "%d %02x:%02x:%ld ", fl->fl_pid,
+ seq_printf(f, "%d %02x:%02x:%ld ", fl_pid,
MAJOR(inode->i_sb->s_dev),
MINOR(inode->i_sb->s_dev), inode->i_ino);
#endif
} else {
- out += sprintf(out, "%d <none>:0 ", fl->fl_pid);
+ seq_printf(f, "%d <none>:0 ", fl_pid);
}
if (IS_POSIX(fl)) {
if (fl->fl_end == OFFSET_MAX)
- out += sprintf(out, "%Ld EOF\n", fl->fl_start);
+ seq_printf(f, "%Ld EOF\n", fl->fl_start);
else
- out += sprintf(out, "%Ld %Ld\n", fl->fl_start,
- fl->fl_end);
+ seq_printf(f, "%Ld %Ld\n", fl->fl_start, fl->fl_end);
} else {
- out += sprintf(out, "0 EOF\n");
+ seq_printf(f, "0 EOF\n");
}
}
-static void move_lock_status(char **p, off_t* pos, off_t offset)
+static int locks_show(struct seq_file *f, void *v)
{
- int len;
- len = strlen(*p);
- if(*pos >= offset) {
- /* the complete line is valid */
- *p += len;
- *pos += len;
- return;
- }
- if(*pos+len > offset) {
- /* use the second part of the line */
- int i = offset-*pos;
- memmove(*p,*p+i,len-i);
- *p += len-i;
- *pos += len;
- return;
- }
- /* discard the complete line */
- *pos += len;
+ struct file_lock *fl, *bfl;
+
+ fl = list_entry(v, struct file_lock, fl_link);
+
+ lock_get_status(f, fl, (long)f->private, "");
+
+ list_for_each_entry(bfl, &fl->fl_block, fl_block)
+ lock_get_status(f, bfl, (long)f->private, " ->");
+
+ f->private++;
+ return 0;
}
-/**
- * get_locks_status - reports lock usage in /proc/locks
- * @buffer: address in userspace to write into
- * @start: ?
- * @offset: how far we are through the buffer
- * @length: how much to read
- */
+static void *locks_start(struct seq_file *f, loff_t *pos)
+{
+ lock_kernel();
+ f->private = (void *)1;
+ return seq_list_start(&file_lock_list, *pos);
+}
-int get_locks_status(char *buffer, char **start, off_t offset, int length)
+static void *locks_next(struct seq_file *f, void *v, loff_t *pos)
{
- struct list_head *tmp;
- char *q = buffer;
- off_t pos = 0;
- int i = 0;
+ return seq_list_next(v, &file_lock_list, pos);
+}
- lock_kernel();
- list_for_each(tmp, &file_lock_list) {
- struct list_head *btmp;
- struct file_lock *fl = list_entry(tmp, struct file_lock, fl_link);
- lock_get_status(q, fl, ++i, "");
- move_lock_status(&q, &pos, offset);
-
- if(pos >= offset+length)
- goto done;
-
- list_for_each(btmp, &fl->fl_block) {
- struct file_lock *bfl = list_entry(btmp,
- struct file_lock, fl_block);
- lock_get_status(q, bfl, i, " ->");
- move_lock_status(&q, &pos, offset);
-
- if(pos >= offset+length)
- goto done;
- }
- }
-done:
+static void locks_stop(struct seq_file *f, void *v)
+{
unlock_kernel();
- *start = buffer;
- if(q-buffer < length)
- return (q-buffer);
- return length;
}
+static const struct seq_operations locks_seq_operations = {
+ .start = locks_start,
+ .next = locks_next,
+ .stop = locks_stop,
+ .show = locks_show,
+};
+
+static int locks_open(struct inode *inode, struct file *filp)
+{
+ return seq_open(filp, &locks_seq_operations);
+}
+
+static const struct file_operations proc_locks_operations = {
+ .open = locks_open,
+ .read = seq_read,
+ .llseek = seq_lseek,
+ .release = seq_release,
+};
+
+static int __init proc_locks_init(void)
+{
+ proc_create("locks", 0, NULL, &proc_locks_operations);
+ return 0;
+}
+module_init(proc_locks_init);
+#endif
+
/**
* lock_may_read - checks that the region is free of locks
* @inode: the inode that is being read
{
filelock_cache = kmem_cache_create("file_lock_cache",
sizeof(struct file_lock), 0, SLAB_PANIC,
- init_once, NULL);
+ init_once);
return 0;
}
git://ftp.safe.ca / safe / jmp / linux-2.6 / blobdiff