diff options
Diffstat (limited to 'fs/locks.c')
-rw-r--r-- | fs/locks.c | 70 |
1 files changed, 53 insertions, 17 deletions
diff --git a/fs/locks.c b/fs/locks.c index b27a3005d78..92a0f0a52b0 100644 --- a/fs/locks.c +++ b/fs/locks.c @@ -134,7 +134,7 @@ #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) +#define IS_LEASE(fl) (fl->fl_flags & (FL_LEASE|FL_DELEG)) static bool lease_breaking(struct file_lock *fl) { @@ -1292,28 +1292,40 @@ static void time_out_leases(struct inode *inode) } } +static bool leases_conflict(struct file_lock *lease, struct file_lock *breaker) +{ + if ((breaker->fl_flags & FL_DELEG) && (lease->fl_flags & FL_LEASE)) + return false; + return locks_conflict(breaker, lease); +} + /** * __break_lease - revoke all outstanding leases on file * @inode: the inode of the file to return - * @mode: the open mode (read or write) + * @mode: O_RDONLY: break only write leases; O_WRONLY or O_RDWR: + * break all leases + * @type: FL_LEASE: break leases and delegations; FL_DELEG: break + * only delegations * * 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 __break_lease(struct inode *inode, unsigned int mode, unsigned int type) { int error = 0; struct file_lock *new_fl, *flock; struct file_lock *fl; unsigned long break_time; int i_have_this_lease = 0; + bool lease_conflict = false; int want_write = (mode & O_ACCMODE) != O_RDONLY; new_fl = lease_alloc(NULL, want_write ? F_WRLCK : F_RDLCK); if (IS_ERR(new_fl)) return PTR_ERR(new_fl); + new_fl->fl_flags = type; spin_lock(&inode->i_lock); @@ -1323,13 +1335,16 @@ int __break_lease(struct inode *inode, unsigned int mode) if ((flock == NULL) || !IS_LEASE(flock)) goto out; - if (!locks_conflict(flock, new_fl)) + for (fl = flock; fl && IS_LEASE(fl); fl = fl->fl_next) { + if (leases_conflict(fl, new_fl)) { + lease_conflict = true; + if (fl->fl_owner == current->files) + i_have_this_lease = 1; + } + } + if (!lease_conflict) goto out; - for (fl = flock; fl && IS_LEASE(fl); fl = fl->fl_next) - if (fl->fl_owner == current->files) - i_have_this_lease = 1; - break_time = 0; if (lease_break_time > 0) { break_time = jiffies + lease_break_time * HZ; @@ -1338,6 +1353,8 @@ int __break_lease(struct inode *inode, unsigned int mode) } for (fl = flock; fl && IS_LEASE(fl); fl = fl->fl_next) { + if (!leases_conflict(fl, new_fl)) + continue; if (want_write) { if (fl->fl_flags & FL_UNLOCK_PENDING) continue; @@ -1379,7 +1396,7 @@ restart: */ for (flock = inode->i_flock; flock && IS_LEASE(flock); flock = flock->fl_next) { - if (locks_conflict(new_fl, flock)) + if (leases_conflict(new_fl, flock)) goto restart; } error = 0; @@ -1460,9 +1477,27 @@ static int generic_add_lease(struct file *filp, long arg, struct file_lock **flp struct file_lock *fl, **before, **my_before = NULL, *lease; struct dentry *dentry = filp->f_path.dentry; struct inode *inode = dentry->d_inode; + bool is_deleg = (*flp)->fl_flags & FL_DELEG; int error; lease = *flp; + /* + * In the delegation case we need mutual exclusion with + * a number of operations that take the i_mutex. We trylock + * because delegations are an optional optimization, and if + * there's some chance of a conflict--we'd rather not + * bother, maybe that's a sign this just isn't a good file to + * hand out a delegation on. + */ + if (is_deleg && !mutex_trylock(&inode->i_mutex)) + return -EAGAIN; + + if (is_deleg && arg == F_WRLCK) { + /* Write delegations are not currently supported: */ + mutex_unlock(&inode->i_mutex); + WARN_ON_ONCE(1); + return -EINVAL; + } error = -EAGAIN; if ((arg == F_RDLCK) && (atomic_read(&inode->i_writecount) > 0)) @@ -1514,9 +1549,10 @@ static int generic_add_lease(struct file *filp, long arg, struct file_lock **flp goto out; locks_insert_lock(before, lease); - return 0; - + error = 0; out: + if (is_deleg) + mutex_unlock(&inode->i_mutex); return error; } @@ -1579,7 +1615,7 @@ EXPORT_SYMBOL(generic_setlease); static int __vfs_setlease(struct file *filp, long arg, struct file_lock **lease) { - if (filp->f_op && filp->f_op->setlease) + if (filp->f_op->setlease) return filp->f_op->setlease(filp, arg, lease); else return generic_setlease(filp, arg, lease); @@ -1771,7 +1807,7 @@ SYSCALL_DEFINE2(flock, unsigned int, fd, unsigned int, cmd) if (error) goto out_free; - if (f.file->f_op && f.file->f_op->flock) + if (f.file->f_op->flock) error = f.file->f_op->flock(f.file, (can_sleep) ? F_SETLKW : F_SETLK, lock); @@ -1797,7 +1833,7 @@ SYSCALL_DEFINE2(flock, unsigned int, fd, unsigned int, cmd) */ int vfs_test_lock(struct file *filp, struct file_lock *fl) { - if (filp->f_op && filp->f_op->lock) + if (filp->f_op->lock) return filp->f_op->lock(filp, F_GETLK, fl); posix_test_lock(filp, fl); return 0; @@ -1909,7 +1945,7 @@ out: */ 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) + if (filp->f_op->lock) return filp->f_op->lock(filp, cmd, fl); else return posix_lock_file(filp, fl, conf); @@ -2182,7 +2218,7 @@ void locks_remove_flock(struct file *filp) if (!inode->i_flock) return; - if (filp->f_op && filp->f_op->flock) { + if (filp->f_op->flock) { struct file_lock fl = { .fl_pid = current->tgid, .fl_file = filp, @@ -2246,7 +2282,7 @@ EXPORT_SYMBOL(posix_unblock_lock); */ int vfs_cancel_lock(struct file *filp, struct file_lock *fl) { - if (filp->f_op && filp->f_op->lock) + if (filp->f_op->lock) return filp->f_op->lock(filp, F_CANCELLK, fl); return 0; } |