X-Git-Url: http://ftp.safe.ca/?a=blobdiff_plain;ds=sidebyside;f=fs%2Flocks.c;h=431a8b871fcef03ea098f8d8ac8f8602a2d33f66;hb=a35afb830f8d71ec211531aeb9a621b09a2efb39;hp=1792ce547af7b0b6517bd2779600f4dfe03514a5;hpb=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2;p=safe%2Fjmp%2Flinux-2.6 diff --git a/fs/locks.c b/fs/locks.c index 1792ce5..431a8b8 100644 --- a/fs/locks.c +++ b/fs/locks.c @@ -124,6 +124,7 @@ #include #include #include +#include #include #include @@ -138,48 +139,40 @@ 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 struct kmem_cache *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); + return kmem_cache_alloc(filelock_cache, GFP_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); } @@ -206,35 +199,53 @@ EXPORT_SYMBOL(locks_init_lock); * Initialises the fields of the file lock which are invariant for * free file_locks. */ -static void init_once(void *foo, kmem_cache_t *cache, unsigned long flags) +static void init_once(void *foo, struct kmem_cache *cache, unsigned long flags) { struct file_lock *lock = (struct file_lock *) foo; - if ((flags & (SLAB_CTOR_VERIFY|SLAB_CTOR_CONSTRUCTOR)) != - SLAB_CTOR_CONSTRUCTOR) - return; - 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); @@ -299,14 +310,14 @@ static int flock_to_posix_lock(struct file *filp, struct file_lock *fl, off_t start, end; switch (l->l_whence) { - case 0: /*SEEK_SET*/ + case SEEK_SET: start = 0; break; - case 1: /*SEEK_CUR*/ + case SEEK_CUR: start = filp->f_pos; break; - case 2: /*SEEK_END*/ - start = i_size_read(filp->f_dentry->d_inode); + case SEEK_END: + start = i_size_read(filp->f_path.dentry->d_inode); break; default: return -EINVAL; @@ -315,21 +326,22 @@ static int flock_to_posix_lock(struct file *filp, struct file_lock *fl, /* 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; @@ -348,27 +360,34 @@ static int flock64_to_posix_lock(struct file *filp, struct file_lock *fl, loff_t start; switch (l->l_whence) { - case 0: /*SEEK_SET*/ + case SEEK_SET: start = 0; break; - case 1: /*SEEK_CUR*/ + case SEEK_CUR: start = filp->f_pos; break; - case 2: /*SEEK_END*/ - start = i_size_read(filp->f_dentry->d_inode); + case SEEK_END: + start = i_size_read(filp->f_path.dentry->d_inode); break; default: 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; @@ -406,12 +425,12 @@ static void lease_release_private_callback(struct file_lock *fl) fl->fl_file->f_owner.signum = 0; } -int lease_mylease_callback(struct file_lock *fl, struct file_lock *try) +static int lease_mylease_callback(struct file_lock *fl, struct file_lock *try) { return fl->fl_file == try->fl_file; } -struct lock_manager_operations lease_manager_ops = { +static struct lock_manager_operations lease_manager_ops = { .fl_break = lease_break_callback, .fl_release_private = lease_release_private_callback, .fl_mylease = lease_mylease_callback, @@ -423,15 +442,14 @@ struct lock_manager_operations lease_manager_ops = { */ 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; @@ -443,16 +461,19 @@ static int lease_init(struct file *filp, int type, struct file_lock *fl) 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. @@ -466,8 +487,7 @@ static inline int locks_overlap(struct file_lock *fl1, struct file_lock *fl2) /* * 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 && @@ -478,7 +498,7 @@ posix_same_owner(struct file_lock *fl1, struct file_lock *fl2) /* 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); @@ -502,12 +522,7 @@ 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)) @@ -646,21 +661,26 @@ static int locks_block_on_timeout(struct file_lock *blocker, struct file_lock *w return result; } -struct file_lock * +int posix_test_lock(struct file *filp, struct file_lock *fl) { struct file_lock *cfl; lock_kernel(); - for (cfl = filp->f_dentry->d_inode->i_flock; cfl; cfl = cfl->fl_next) { + 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)) break; } + if (cfl) { + __locks_copy_lock(fl, cfl); + unlock_kernel(); + return 1; + } else + fl->fl_type = F_UNLCK; unlock_kernel(); - - return (cfl); + return 0; } EXPORT_SYMBOL(posix_test_lock); @@ -679,7 +699,7 @@ 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; @@ -698,20 +718,25 @@ next_task: 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; + struct inode * inode = filp->f_path.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)) @@ -720,17 +745,23 @@ 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) { + 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. @@ -738,35 +769,39 @@ static int flock_lock_file(struct file *filp, struct file_lock *new_fl) 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(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; @@ -775,9 +810,15 @@ static int __posix_lock_file(struct inode *inode, struct file_lock *request) /* * 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) { @@ -787,6 +828,8 @@ 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; @@ -804,14 +847,7 @@ static int __posix_lock_file(struct inode *inode, struct file_lock *request) 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. */ @@ -828,12 +864,16 @@ static int __posix_lock_file(struct inode *inode, struct file_lock *request) /* 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 @@ -892,7 +932,8 @@ 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; } @@ -903,10 +944,28 @@ static int __posix_lock_file(struct inode *inode, struct file_lock *request) 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; @@ -944,15 +1003,22 @@ static int __posix_lock_file(struct inode *inode, struct file_lock *request) * 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. * 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) +int posix_lock_file(struct file *filp, struct file_lock *fl, + struct file_lock *conflock) { - return __posix_lock_file(filp->f_dentry->d_inode, fl); + return __posix_lock_file(filp->f_path.dentry->d_inode, fl, conflock); } +EXPORT_SYMBOL(posix_lock_file); /** * posix_lock_file_wait - Apply a POSIX-style lock to a file @@ -968,7 +1034,7 @@ 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, NULL); if ((error != -EAGAIN) || !(fl->fl_flags & FL_SLEEP)) break; error = wait_event_interruptible(fl->fl_wait, !fl->fl_next); @@ -1040,7 +1106,7 @@ 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(inode, &fl, NULL); if (error != -EAGAIN) break; if (!(fl.fl_flags & FL_SLEEP)) @@ -1092,7 +1158,6 @@ static void time_out_leases(struct inode *inode) 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; @@ -1251,8 +1316,8 @@ int fcntl_getlease(struct file *filp) int type = F_UNLCK; lock_kernel(); - time_out_leases(filp->f_dentry->d_inode); - for (fl = filp->f_dentry->d_inode->i_flock; fl && IS_LEASE(fl); + time_out_leases(filp->f_path.dentry->d_inode); + for (fl = filp->f_path.dentry->d_inode->i_flock; fl && IS_LEASE(fl); fl = fl->fl_next) { if (fl->fl_file == filp) { type = fl->fl_type & ~F_INPROGRESS; @@ -1274,10 +1339,10 @@ int fcntl_getlease(struct file *filp) * * Called with kernel lock held. */ -int __setlease(struct file *filp, long arg, struct file_lock **flp) +static int __setlease(struct file *filp, long arg, struct file_lock **flp) { - struct file_lock *fl, **before, **my_before = NULL, *lease = *flp; - struct dentry *dentry = filp->f_dentry; + struct file_lock *fl, **before, **my_before = NULL, *lease; + struct dentry *dentry = filp->f_path.dentry; struct inode *inode = dentry->d_inode; int error, rdlease_count = 0, wrlease_count = 0; @@ -1287,6 +1352,8 @@ int __setlease(struct file *filp, long arg, struct file_lock **flp) if (!flp || !(*flp) || !(*flp)->fl_lmops || !(*flp)->fl_lmops->fl_break) goto out; + lease = *flp; + error = -EAGAIN; if ((arg == F_RDLCK) && (atomic_read(&inode->i_writecount) > 0)) goto out; @@ -1324,6 +1391,7 @@ int __setlease(struct file *filp, long arg, struct file_lock **flp) goto out; if (my_before != NULL) { + *flp = *my_before; error = lease->fl_lmops->fl_change(my_before, arg); goto out; } @@ -1336,8 +1404,9 @@ int __setlease(struct file *filp, long arg, struct file_lock **flp) if (!leases_enable) goto out; - error = lease_alloc(filp, arg, &fl); - if (error) + error = -ENOMEM; + fl = locks_alloc_lock(); + if (fl == NULL) goto out; locks_copy_lock(fl, lease); @@ -1345,6 +1414,7 @@ int __setlease(struct file *filp, long arg, struct file_lock **flp) locks_insert_lock(before, fl); *flp = fl; + error = 0; out: return error; } @@ -1361,7 +1431,7 @@ out: int setlease(struct file *filp, long arg, struct file_lock **lease) { - struct dentry *dentry = filp->f_dentry; + struct dentry *dentry = filp->f_path.dentry; struct inode *inode = dentry->d_inode; int error; @@ -1395,7 +1465,7 @@ EXPORT_SYMBOL(setlease); int fcntl_setlease(unsigned int fd, struct file *filp, long arg) { struct file_lock fl, *flp = &fl; - struct dentry *dentry = filp->f_dentry; + struct dentry *dentry = filp->f_path.dentry; struct inode *inode = dentry->d_inode; int error; @@ -1415,7 +1485,7 @@ int fcntl_setlease(unsigned int fd, struct file *filp, long arg) 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); @@ -1427,7 +1497,7 @@ int fcntl_setlease(unsigned int fd, struct file *filp, long arg) goto out_unlock; } - error = f_setown(filp, current->pid, 0); + error = __f_setown(filp, task_pid(current), PIDTYPE_PID, 0); out_unlock: unlock_kernel(); return error; @@ -1516,9 +1586,7 @@ 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); @@ -1526,12 +1594,63 @@ asmlinkage long sys_flock(unsigned int fd, unsigned int cmd) return error; } +/** + * vfs_test_lock - test file byte range lock + * @filp: The file to test lock for + * @fl: The lock to test + * @conf: Place to return a copy of the conflicting lock, if found + * + * 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, file_lock; + struct file_lock file_lock; struct flock flock; int error; @@ -1546,36 +1665,15 @@ int fcntl_getlk(struct file *filp, struct flock __user *l) if (error) goto out; - if (filp->f_op && filp->f_op->lock) { - error = filp->f_op->lock(filp, F_GETLK, &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); - } + 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) + 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; - if ((fl->fl_end != OFFSET_MAX) - && (fl->fl_end > OFFT_OFFSET_MAX)) - 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))) @@ -1584,10 +1682,53 @@ out: 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 -EINPROGRESS, and call ->fl_grant() when the lock + * request completes. + * If the request is for non-blocking lock the file system should return + * -EINPROGRESS 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 -EINPROGRESS + * 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); + /* Apply the lock described by l to an open file descriptor. * This implements both the F_SETLK and F_SETLKW commands of fcntl(). */ -int fcntl_setlk(struct file *filp, unsigned int cmd, struct flock __user *l) +int fcntl_setlk(unsigned int fd, struct file *filp, unsigned int cmd, + struct flock __user *l) { struct file_lock *file_lock = locks_alloc_lock(); struct flock flock; @@ -1604,7 +1745,7 @@ int fcntl_setlk(struct file *filp, unsigned int cmd, struct flock __user *l) if (copy_from_user(&flock, l, sizeof(flock))) goto out; - inode = filp->f_dentry->d_inode; + inode = filp->f_path.dentry->d_inode; /* Don't allow mandatory locks on files that may be memory mapped * and shared. @@ -1616,6 +1757,7 @@ int fcntl_setlk(struct file *filp, unsigned int cmd, struct flock __user *l) goto out; } +again: error = flock_to_posix_lock(filp, file_lock, &flock); if (error) goto out; @@ -1644,14 +1786,9 @@ int fcntl_setlk(struct file *filp, unsigned int cmd, struct flock __user *l) if (error) goto out; - if (filp->f_op && filp->f_op->lock != NULL) { - error = filp->f_op->lock(filp, cmd, file_lock); - goto out; - } - for (;;) { - error = __posix_lock_file(inode, file_lock); - if ((error != -EAGAIN) || (cmd == F_SETLK)) + error = vfs_lock_file(filp, cmd, file_lock, NULL); + if (error != -EAGAIN || cmd == F_SETLK) break; error = wait_event_interruptible(file_lock->fl_wait, !file_lock->fl_next); @@ -1662,7 +1799,16 @@ int fcntl_setlk(struct file *filp, unsigned int cmd, struct flock __user *l) break; } - out: + /* + * 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) { + flock.l_type = F_UNLCK; + goto again; + } + +out: locks_free_lock(file_lock); return error; } @@ -1673,7 +1819,7 @@ int fcntl_setlk(struct file *filp, unsigned int cmd, struct flock __user *l) */ int fcntl_getlk64(struct file *filp, struct flock64 __user *l) { - struct file_lock *fl, file_lock; + struct file_lock file_lock; struct flock64 flock; int error; @@ -1688,25 +1834,14 @@ int fcntl_getlk64(struct file *filp, struct flock64 __user *l) if (error) goto out; - if (filp->f_op && filp->f_op->lock) { - error = filp->f_op->lock(filp, F_GETLK, &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); - } - - 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; @@ -1718,7 +1853,8 @@ out: /* Apply the lock described by l to an open file descriptor. * This implements both the F_SETLK and F_SETLKW commands of fcntl(). */ -int fcntl_setlk64(struct file *filp, unsigned int cmd, struct flock64 __user *l) +int fcntl_setlk64(unsigned int fd, struct file *filp, unsigned int cmd, + struct flock64 __user *l) { struct file_lock *file_lock = locks_alloc_lock(); struct flock64 flock; @@ -1735,7 +1871,7 @@ int fcntl_setlk64(struct file *filp, unsigned int cmd, struct flock64 __user *l) if (copy_from_user(&flock, l, sizeof(flock))) goto out; - inode = filp->f_dentry->d_inode; + inode = filp->f_path.dentry->d_inode; /* Don't allow mandatory locks on files that may be memory mapped * and shared. @@ -1747,6 +1883,7 @@ int fcntl_setlk64(struct file *filp, unsigned int cmd, struct flock64 __user *l) goto out; } +again: error = flock64_to_posix_lock(filp, file_lock, &flock); if (error) goto out; @@ -1775,14 +1912,9 @@ int fcntl_setlk64(struct file *filp, unsigned int cmd, struct flock64 __user *l) if (error) goto out; - if (filp->f_op && filp->f_op->lock != NULL) { - error = filp->f_op->lock(filp, cmd, file_lock); - goto out; - } - for (;;) { - error = __posix_lock_file(inode, file_lock); - if ((error != -EAGAIN) || (cmd == F_SETLK64)) + error = vfs_lock_file(filp, cmd, file_lock, NULL); + if (error != -EAGAIN || cmd == F_SETLK64) break; error = wait_event_interruptible(file_lock->fl_wait, !file_lock->fl_next); @@ -1793,6 +1925,15 @@ int fcntl_setlk64(struct file *filp, unsigned int cmd, struct flock64 __user *l) break; } + /* + * 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) { + flock.l_type = F_UNLCK; + goto again; + } + out: locks_free_lock(file_lock); return error; @@ -1806,19 +1947,18 @@ out: */ 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_path.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; @@ -1827,25 +1967,8 @@ void locks_remove_posix(struct file *filp, fl_owner_t owner) 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); - goto out; - } + vfs_lock_file(filp, F_SETLK, &lock, NULL); - /* 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); } @@ -1857,7 +1980,7 @@ EXPORT_SYMBOL(locks_remove_posix); */ void locks_remove_flock(struct file *filp) { - struct inode * inode = filp->f_dentry->d_inode; + struct inode * inode = filp->f_path.dentry->d_inode; struct file_lock *fl; struct file_lock **before; @@ -1873,6 +1996,8 @@ void locks_remove_flock(struct file *filp) .fl_end = OFFSET_MAX, }; filp->f_op->flock(filp, F_SETLKW, &fl); + if (fl.fl_ops && fl.fl_ops->fl_release_private) + fl.fl_ops->fl_release_private(&fl); } lock_kernel(); @@ -1880,12 +2005,7 @@ void locks_remove_flock(struct file *filp) while ((fl = *before) != NULL) { if (fl->fl_file == filp) { - /* - * We might have a POSIX lock that was created at the same time - * the filp was closed for the last time. Just remove that too, - * regardless of ownership, since nobody can own it. - */ - if (IS_FLOCK(fl) || IS_POSIX(fl)) { + if (IS_FLOCK(fl)) { locks_delete_lock(before); continue; } @@ -1902,53 +2022,50 @@ 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 * * 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); +/** + * 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); + static void lock_get_status(char* out, struct file_lock *fl, int id, char *pfx) { struct inode *inode = NULL; if (fl->fl_file != NULL) - inode = fl->fl_file->f_dentry->d_inode; + inode = fl->fl_file->f_path.dentry->d_inode; out += sprintf(out, "%d:%s ", id, pfx); if (IS_POSIX(fl)) { @@ -2153,54 +2270,6 @@ int lock_may_write(struct inode *inode, loff_t start, unsigned long len) 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; - - if (from == files) - return; - - lock_kernel(); - j = 0; - for (;;) { - unsigned long set; - i = j * __NFDBITS; - if (i >= files->max_fdset || i >= files->max_fds) - break; - set = files->open_fds->fds_bits[j++]; - while (set) { - if (set & 1) { - struct file *file = files->fd[i]; - if (file) - __steal_locks(file, from); - } - i++; - set >>= 1; - } - } - unlock_kernel(); -} -EXPORT_SYMBOL(steal_locks); - static int __init filelock_init(void) { filelock_cache = kmem_cache_create("file_lock_cache",