#define IS_POSIX(fl) (fl->fl_flags & FL_POSIX)
#define IS_FLOCK(fl) (fl->fl_flags & FL_FLOCK)
#define IS_LEASE(fl) (fl->fl_flags & (FL_LEASE|FL_DELEG))
+#define IS_FILE_PVT(fl) (fl->fl_flags & FL_FILE_PVT)
static bool lease_breaking(struct file_lock *fl)
{
return 0;
}
-/* Verify a "struct flock" and copy it to a "struct file_lock" as a POSIX
- * style lock.
- */
-static int flock_to_posix_lock(struct file *filp, struct file_lock *fl,
- struct flock *l)
+static int flock64_to_posix_lock(struct file *filp, struct file_lock *fl,
+ struct flock64 *l)
{
- off_t start, end;
-
switch (l->l_whence) {
case SEEK_SET:
- start = 0;
+ fl->fl_start = 0;
break;
case SEEK_CUR:
- start = filp->f_pos;
+ fl->fl_start = filp->f_pos;
break;
case SEEK_END:
- start = i_size_read(file_inode(filp));
+ fl->fl_start = i_size_read(file_inode(filp));
break;
default:
return -EINVAL;
}
+ if (l->l_start > OFFSET_MAX - fl->fl_start)
+ return -EOVERFLOW;
+ fl->fl_start += l->l_start;
+ if (fl->fl_start < 0)
+ return -EINVAL;
/* POSIX-1996 leaves the case l->l_len < 0 undefined;
POSIX-2001 defines it. */
- start += l->l_start;
- 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;
+ if (l->l_len - 1 > OFFSET_MAX - fl->fl_start)
+ return -EOVERFLOW;
+ fl->fl_end = fl->fl_start + l->l_len - 1;
+
} else if (l->l_len < 0) {
- end = start - 1;
- fl->fl_end = end;
- start += l->l_len;
- if (start < 0)
+ if (fl->fl_start + l->l_len < 0)
return -EINVAL;
- }
- fl->fl_start = start; /* we record the absolute position */
- if (fl->fl_end < fl->fl_start)
- return -EOVERFLOW;
-
+ fl->fl_end = fl->fl_start - 1;
+ fl->fl_start += l->l_len;
+ } else
+ fl->fl_end = OFFSET_MAX;
+
fl->fl_owner = current->files;
fl->fl_pid = current->tgid;
fl->fl_file = filp;
fl->fl_ops = NULL;
fl->fl_lmops = NULL;
- return assign_type(fl, l->l_type);
-}
-
-#if BITS_PER_LONG == 32
-static int flock64_to_posix_lock(struct file *filp, struct file_lock *fl,
- struct flock64 *l)
-{
- loff_t start;
-
- switch (l->l_whence) {
- case SEEK_SET:
- start = 0;
- break;
- case SEEK_CUR:
- start = filp->f_pos;
+ /* Ensure that fl->fl_filp has compatible f_mode */
+ switch (l->l_type) {
+ case F_RDLCK:
+ if (!(filp->f_mode & FMODE_READ))
+ return -EBADF;
break;
- case SEEK_END:
- start = i_size_read(file_inode(filp));
+ case F_WRLCK:
+ if (!(filp->f_mode & FMODE_WRITE))
+ return -EBADF;
break;
- default:
- return -EINVAL;
}
- start += l->l_start;
- if (start < 0)
- return -EINVAL;
- 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 (fl->fl_end < fl->fl_start)
- return -EOVERFLOW;
-
- fl->fl_owner = current->files;
- fl->fl_pid = current->tgid;
- fl->fl_file = filp;
- fl->fl_flags = FL_POSIX;
- fl->fl_ops = NULL;
- fl->fl_lmops = NULL;
-
return assign_type(fl, l->l_type);
}
-#endif
+
+/* Verify a "struct flock" and copy it to a "struct file_lock" as a POSIX
+ * style lock.
+ */
+static int flock_to_posix_lock(struct file *filp, struct file_lock *fl,
+ struct flock *l)
+{
+ struct flock64 ll = {
+ .l_type = l->l_type,
+ .l_whence = l->l_whence,
+ .l_start = l->l_start,
+ .l_len = l->l_len,
+ };
+
+ return flock64_to_posix_lock(filp, fl, &ll);
+}
/* default lease lock manager operations */
static void lease_break_callback(struct file_lock *fl)
}
/* Must be called with the i_lock held! */
-static inline void
-locks_insert_global_locks(struct file_lock *fl)
+static void locks_insert_global_locks(struct file_lock *fl)
{
lg_local_lock(&file_lock_lglock);
fl->fl_link_cpu = smp_processor_id();
}
/* Must be called with the i_lock held! */
-static inline void
-locks_delete_global_locks(struct file_lock *fl)
+static void locks_delete_global_locks(struct file_lock *fl)
{
/*
* Avoid taking lock if already unhashed. This is safe since this check
return (unsigned long)fl->fl_owner;
}
-static inline void
-locks_insert_global_blocked(struct file_lock *waiter)
+static void locks_insert_global_blocked(struct file_lock *waiter)
{
hash_add(blocked_hash, &waiter->fl_link, posix_owner_key(waiter));
}
-static inline void
-locks_delete_global_blocked(struct file_lock *waiter)
+static void locks_delete_global_blocked(struct file_lock *waiter)
{
hash_del(&waiter->fl_link);
}
* it seems like the reasonable thing to do.
*
* Must be called with both the i_lock and blocked_lock_lock held. The fl_block
- * list itself is protected by the file_lock_list, but by ensuring that the
+ * list itself is protected by the blocked_lock_lock, but by ensuring that the
* i_lock is also held on insertions we can avoid taking the blocked_lock_lock
* in some cases when we see that the fl_block list is empty.
*/
BUG_ON(!list_empty(&waiter->fl_block));
waiter->fl_next = blocker;
list_add_tail(&waiter->fl_block, &blocker->fl_block);
- if (IS_POSIX(blocker))
+ if (IS_POSIX(blocker) && !IS_FILE_PVT(blocker))
locks_insert_global_blocked(waiter);
}
locks_insert_global_locks(fl);
}
-/*
- * Delete a lock and then free it.
- * Wake up processes that are blocked waiting for this lock,
- * notify the FS that the lock has been cleared and
- * finally free the lock.
+/**
+ * locks_delete_lock - Delete a lock and then free it.
+ * @thisfl_p: pointer that points to the fl_next field of the previous
+ * inode->i_flock list entry
+ *
+ * Unlink a lock from all lists and free the namespace reference, but don't
+ * free it yet. Wake up processes that are blocked waiting for this lock and
+ * notify the FS that the lock has been cleared.
*
* Must be called with the i_lock held!
*/
-static void locks_delete_lock(struct file_lock **thisfl_p)
+static void locks_unlink_lock(struct file_lock **thisfl_p)
{
struct file_lock *fl = *thisfl_p;
}
locks_wake_up_blocks(fl);
+}
+
+/*
+ * Unlink a lock from all lists and free it.
+ *
+ * Must be called with i_lock held!
+ */
+static void locks_delete_lock(struct file_lock **thisfl_p)
+{
+ struct file_lock *fl = *thisfl_p;
+
+ locks_unlink_lock(thisfl_p);
locks_free_lock(fl);
}
* 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.
+ *
+ * For FL_FILE_PVT locks, the owner is the filp, not the files_struct.
+ * Because the owner is not even nominally tied to a thread of
+ * execution, the deadlock detection below can't reasonably work well. Just
+ * skip it for those.
+ *
+ * In principle, we could do a more limited deadlock detection on FL_FILE_PVT
+ * locks that just checks for the case where two tasks are attempting to
+ * upgrade from read to write locks on the same inode.
*/
#define MAX_DEADLK_ITERATIONS 10
{
int i = 0;
+ /*
+ * This deadlock detector can't reasonably detect deadlocks with
+ * FL_FILE_PVT locks, since they aren't owned by a process, per-se.
+ */
+ if (IS_FILE_PVT(caller_fl))
+ return 0;
+
while ((block_fl = what_owner_is_waiting_for(block_fl))) {
if (i++ > MAX_DEADLK_ITERATIONS)
return 0;
/**
* locks_mandatory_locked - Check for an active lock
- * @inode: the file to check
+ * @file: the file to check
*
* Searches the inode's list of locks to find any POSIX locks which conflict.
* This function is called from locks_verify_locked() only.
*/
-int locks_mandatory_locked(struct inode *inode)
+int locks_mandatory_locked(struct file *file)
{
+ struct inode *inode = file_inode(file);
fl_owner_t owner = current->files;
struct file_lock *fl;
for (fl = inode->i_flock; fl != NULL; fl = fl->fl_next) {
if (!IS_POSIX(fl))
continue;
- if (fl->fl_owner != owner)
+ if (fl->fl_owner != owner && fl->fl_owner != (fl_owner_t)file)
break;
}
spin_unlock(&inode->i_lock);
{
struct file_lock fl;
int error;
+ bool sleep = false;
locks_init_lock(&fl);
- fl.fl_owner = current->files;
fl.fl_pid = current->tgid;
fl.fl_file = filp;
fl.fl_flags = FL_POSIX | FL_ACCESS;
if (filp && !(filp->f_flags & O_NONBLOCK))
- fl.fl_flags |= FL_SLEEP;
+ sleep = true;
fl.fl_type = (read_write == FLOCK_VERIFY_WRITE) ? F_WRLCK : F_RDLCK;
fl.fl_start = offset;
fl.fl_end = offset + count - 1;
for (;;) {
+ if (filp) {
+ fl.fl_owner = (fl_owner_t)filp;
+ fl.fl_flags &= ~FL_SLEEP;
+ error = __posix_lock_file(inode, &fl, NULL);
+ if (!error)
+ break;
+ }
+
+ if (sleep)
+ fl.fl_flags |= FL_SLEEP;
+ fl.fl_owner = current->files;
error = __posix_lock_file(inode, &fl, NULL);
if (error != FILE_LOCK_DEFERRED)
break;
return type;
}
+/**
+ * check_conflicting_open - see if the given dentry points to a file that has
+ * an existing open that would conflict with the
+ * desired lease.
+ * @dentry: dentry to check
+ * @arg: type of lease that we're trying to acquire
+ *
+ * Check to see if there's an existing open fd on this file that would
+ * conflict with the lease we're trying to set.
+ */
+static int
+check_conflicting_open(const struct dentry *dentry, const long arg)
+{
+ int ret = 0;
+ struct inode *inode = dentry->d_inode;
+
+ if ((arg == F_RDLCK) && (atomic_read(&inode->i_writecount) > 0))
+ return -EAGAIN;
+
+ if ((arg == F_WRLCK) && ((d_count(dentry) > 1) ||
+ (atomic_read(&inode->i_count) > 1)))
+ ret = -EAGAIN;
+
+ return ret;
+}
+
static int generic_add_lease(struct file *filp, long arg, struct file_lock **flp)
{
struct file_lock *fl, **before, **my_before = NULL, *lease;
return -EINVAL;
}
- error = -EAGAIN;
- if ((arg == F_RDLCK) && (atomic_read(&inode->i_writecount) > 0))
- goto out;
- if ((arg == F_WRLCK)
- && ((d_count(dentry) > 1)
- || (atomic_read(&inode->i_count) > 1)))
+ error = check_conflicting_open(dentry, arg);
+ if (error)
goto out;
/*
goto out;
locks_insert_lock(before, lease);
- error = 0;
+ /*
+ * The check in break_lease() is lockless. It's possible for another
+ * open to race in after we did the earlier check for a conflicting
+ * open but before the lease was inserted. Check again for a
+ * conflicting open and cancel the lease if there is one.
+ *
+ * We also add a barrier here to ensure that the insertion of the lock
+ * precedes these checks.
+ */
+ smp_mb();
+ error = check_conflicting_open(dentry, arg);
+ if (error)
+ locks_unlink_lock(flp);
out:
if (is_deleg)
mutex_unlock(&inode->i_mutex);
static int posix_lock_to_flock(struct flock *flock, struct file_lock *fl)
{
- flock->l_pid = fl->fl_pid;
+ flock->l_pid = IS_FILE_PVT(fl) ? -1 : fl->fl_pid;
#if BITS_PER_LONG == 32
/*
* Make sure we can represent the posix lock via
#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_pid = IS_FILE_PVT(fl) ? -1 : 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;
/* 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)
+int fcntl_getlk(struct file *filp, unsigned int cmd, struct flock __user *l)
{
struct file_lock file_lock;
struct flock flock;
if (error)
goto out;
+ if (cmd == F_GETLKP) {
+ error = -EINVAL;
+ if (flock.l_pid != 0)
+ goto out;
+
+ cmd = F_GETLK;
+ file_lock.fl_flags |= FL_FILE_PVT;
+ file_lock.fl_owner = (fl_owner_t)filp;
+ }
+
error = vfs_test_lock(filp, &file_lock);
if (error)
goto out;
error = flock_to_posix_lock(filp, file_lock, &flock);
if (error)
goto out;
- if (cmd == F_SETLKW) {
- file_lock->fl_flags |= FL_SLEEP;
- }
-
- error = -EBADF;
- switch (flock.l_type) {
- case F_RDLCK:
- if (!(filp->f_mode & FMODE_READ))
- goto out;
- break;
- case F_WRLCK:
- if (!(filp->f_mode & FMODE_WRITE))
+
+ /*
+ * If the cmd is requesting file-private locks, then set the
+ * FL_FILE_PVT flag and override the owner.
+ */
+ switch (cmd) {
+ case F_SETLKP:
+ error = -EINVAL;
+ if (flock.l_pid != 0)
goto out;
+
+ cmd = F_SETLK;
+ file_lock->fl_flags |= FL_FILE_PVT;
+ file_lock->fl_owner = (fl_owner_t)filp;
break;
- case F_UNLCK:
- break;
- default:
+ case F_SETLKPW:
error = -EINVAL;
- goto out;
+ if (flock.l_pid != 0)
+ goto out;
+
+ cmd = F_SETLKW;
+ file_lock->fl_flags |= FL_FILE_PVT;
+ file_lock->fl_owner = (fl_owner_t)filp;
+ /* Fallthrough */
+ case F_SETLKW:
+ file_lock->fl_flags |= FL_SLEEP;
}
error = do_lock_file_wait(filp, cmd, file_lock);
/* Report the first existing lock that would conflict with l.
* This implements the F_GETLK command of fcntl().
*/
-int fcntl_getlk64(struct file *filp, struct flock64 __user *l)
+int fcntl_getlk64(struct file *filp, unsigned int cmd, struct flock64 __user *l)
{
struct file_lock file_lock;
struct flock64 flock;
if (error)
goto out;
+ if (cmd == F_GETLKP) {
+ error = -EINVAL;
+ if (flock.l_pid != 0)
+ goto out;
+
+ cmd = F_GETLK64;
+ file_lock.fl_flags |= FL_FILE_PVT;
+ file_lock.fl_owner = (fl_owner_t)filp;
+ }
+
error = vfs_test_lock(filp, &file_lock);
if (error)
goto out;
error = flock64_to_posix_lock(filp, file_lock, &flock);
if (error)
goto out;
- if (cmd == F_SETLKW64) {
- file_lock->fl_flags |= FL_SLEEP;
- }
-
- error = -EBADF;
- switch (flock.l_type) {
- case F_RDLCK:
- if (!(filp->f_mode & FMODE_READ))
- goto out;
- break;
- case F_WRLCK:
- if (!(filp->f_mode & FMODE_WRITE))
+
+ /*
+ * If the cmd is requesting file-private locks, then set the
+ * FL_FILE_PVT flag and override the owner.
+ */
+ switch (cmd) {
+ case F_SETLKP:
+ error = -EINVAL;
+ if (flock.l_pid != 0)
goto out;
+
+ cmd = F_SETLK64;
+ file_lock->fl_flags |= FL_FILE_PVT;
+ file_lock->fl_owner = (fl_owner_t)filp;
break;
- case F_UNLCK:
- break;
- default:
+ case F_SETLKPW:
error = -EINVAL;
- goto out;
+ if (flock.l_pid != 0)
+ goto out;
+
+ cmd = F_SETLKW64;
+ file_lock->fl_flags |= FL_FILE_PVT;
+ file_lock->fl_owner = (fl_owner_t)filp;
+ /* Fallthrough */
+ case F_SETLKW64:
+ file_lock->fl_flags |= FL_SLEEP;
}
error = do_lock_file_wait(filp, cmd, file_lock);
/*
* This function is called on the last close of an open file.
*/
-void locks_remove_flock(struct file *filp)
+void locks_remove_file(struct file *filp)
{
struct inode * inode = file_inode(filp);
struct file_lock *fl;
if (!inode->i_flock)
return;
+ locks_remove_posix(filp, (fl_owner_t)filp);
+
if (filp->f_op->flock) {
struct file_lock fl = {
.fl_pid = current->tgid,
while ((fl = *before) != NULL) {
if (fl->fl_file == filp) {
- if (IS_FLOCK(fl)) {
- locks_delete_lock(before);
- continue;
- }
if (IS_LEASE(fl)) {
lease_modify(before, F_UNLCK);
continue;
}
- /* What? */
- BUG();
+
+ /*
+ * There's a leftover lock on the list of a type that
+ * we didn't expect to see. Most likely a classic
+ * POSIX lock that ended up not getting released
+ * properly, or that raced onto the list somehow. Log
+ * some info about it and then just remove it from
+ * the list.
+ */
+ WARN(!IS_FLOCK(fl),
+ "leftover lock: dev=%u:%u ino=%lu type=%hhd flags=0x%x start=%lld end=%lld\n",
+ MAJOR(inode->i_sb->s_dev),
+ MINOR(inode->i_sb->s_dev), inode->i_ino,
+ fl->fl_type, fl->fl_flags,
+ fl->fl_start, fl->fl_end);
+
+ locks_delete_lock(before);
+ continue;
}
before = &fl->fl_next;
}
seq_printf(f, "%lld:%s ", id, pfx);
if (IS_POSIX(fl)) {
- seq_printf(f, "%6s %s ",
- (fl->fl_flags & FL_ACCESS) ? "ACCESS" : "POSIX ",
+ if (fl->fl_flags & FL_ACCESS)
+ seq_printf(f, "ACCESS");
+ else if (IS_FILE_PVT(fl))
+ seq_printf(f, "FLPVT ");
+ else
+ seq_printf(f, "POSIX ");
+
+ seq_printf(f, " %s ",
(inode == NULL) ? "*NOINODE*" :
mandatory_lock(inode) ? "MANDATORY" : "ADVISORY ");
} else if (IS_FLOCK(fl)) {
}
static void *locks_start(struct seq_file *f, loff_t *pos)
+ __acquires(&blocked_lock_lock)
{
struct locks_iterator *iter = f->private;
}
static void locks_stop(struct seq_file *f, void *v)
+ __releases(&blocked_lock_lock)
{
spin_unlock(&blocked_lock_lock);
lg_global_unlock(&file_lock_lglock);
projects / linux.git / blobdiff