diff options
Diffstat (limited to 'fs/locks.c')
-rw-r--r-- | fs/locks.c | 176 |
1 files changed, 97 insertions, 79 deletions
diff --git a/fs/locks.c b/fs/locks.c index 909eab8fb1d..dda83d6cd48 100644 --- a/fs/locks.c +++ b/fs/locks.c @@ -139,13 +139,10 @@ int lease_break_time = 45; #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) @@ -153,34 +150,29 @@ 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 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); } @@ -218,24 +210,46 @@ static void init_once(void *foo, kmem_cache_t *cache, unsigned long flags) 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); @@ -510,12 +524,7 @@ static void locks_delete_block(struct file_lock *waiter) 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)) @@ -654,8 +663,9 @@ static int locks_block_on_timeout(struct file_lock *blocker, struct file_lock *w 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; @@ -666,9 +676,13 @@ posix_test_lock(struct file *filp, struct file_lock *fl) 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); @@ -712,8 +726,9 @@ EXPORT_SYMBOL(posix_locks_deadlock); * 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; @@ -728,17 +743,19 @@ static int flock_lock_file(struct file *filp, struct file_lock *new_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) + 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. @@ -746,32 +763,31 @@ static int flock_lock_file(struct file *filp, struct file_lock *new_fl) 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; @@ -795,6 +811,8 @@ static int __posix_lock_file(struct inode *inode, struct file_lock *request) 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; @@ -904,7 +922,8 @@ static int __posix_lock_file(struct inode *inode, struct file_lock *request) 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; } @@ -963,8 +982,24 @@ static int __posix_lock_file(struct inode *inode, struct file_lock *request) */ 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 @@ -980,7 +1015,7 @@ int posix_lock_file_wait(struct file *filp, struct file_lock *fl) 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); @@ -1052,7 +1087,7 @@ int locks_mandatory_area(int read_write, struct inode *inode, 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)) @@ -1529,9 +1564,7 @@ asmlinkage long sys_flock(unsigned int fd, unsigned int cmd) 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); @@ -1544,7 +1577,7 @@ asmlinkage long sys_flock(unsigned int fd, unsigned int cmd) */ 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; @@ -1568,7 +1601,7 @@ int fcntl_getlk(struct file *filp, struct flock __user *l) 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; @@ -1665,7 +1698,7 @@ again: 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, @@ -1698,7 +1731,7 @@ out: */ 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; @@ -1722,7 +1755,7 @@ int fcntl_getlk64(struct file *filp, struct flock64 __user *l) 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; @@ -1808,7 +1841,7 @@ again: 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, @@ -1936,21 +1969,6 @@ void locks_remove_flock(struct file *filp) } /** - * 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 |