diff options
Diffstat (limited to 'fs/locks.c')
-rw-r--r-- | fs/locks.c | 173 |
1 files changed, 119 insertions, 54 deletions
diff --git a/fs/locks.c b/fs/locks.c index 0fca9d680978..607f94a0e789 100644 --- a/fs/locks.c +++ b/fs/locks.c @@ -62,6 +62,7 @@ #include <linux/pid_namespace.h> #include <linux/hashtable.h> #include <linux/percpu.h> +#include <linux/sysctl.h> #define CREATE_TRACE_POINTS #include <trace/events/filelock.h> @@ -88,8 +89,37 @@ static int target_leasetype(struct file_lock *fl) return fl->fl_type; } -int leases_enable = 1; -int lease_break_time = 45; +static int leases_enable = 1; +static int lease_break_time = 45; + +#ifdef CONFIG_SYSCTL +static struct ctl_table locks_sysctls[] = { + { + .procname = "leases-enable", + .data = &leases_enable, + .maxlen = sizeof(int), + .mode = 0644, + .proc_handler = proc_dointvec, + }, +#ifdef CONFIG_MMU + { + .procname = "lease-break-time", + .data = &lease_break_time, + .maxlen = sizeof(int), + .mode = 0644, + .proc_handler = proc_dointvec, + }, +#endif /* CONFIG_MMU */ + {} +}; + +static int __init init_fs_locks_sysctls(void) +{ + register_sysctl_init("fs", locks_sysctls); + return 0; +} +early_initcall(init_fs_locks_sysctls); +#endif /* CONFIG_SYSCTL */ /* * The global file_lock_list is only used for displaying /proc/locks, so we @@ -270,6 +300,34 @@ void locks_release_private(struct file_lock *fl) } EXPORT_SYMBOL_GPL(locks_release_private); +/** + * locks_owner_has_blockers - Check for blocking lock requests + * @flctx: file lock context + * @owner: lock owner + * + * Return values: + * %true: @owner has at least one blocker + * %false: @owner has no blockers + */ +bool locks_owner_has_blockers(struct file_lock_context *flctx, + fl_owner_t owner) +{ + struct file_lock *fl; + + spin_lock(&flctx->flc_lock); + list_for_each_entry(fl, &flctx->flc_posix, fl_list) { + if (fl->fl_owner != owner) + continue; + if (!list_empty(&fl->fl_blocked_requests)) { + spin_unlock(&flctx->flc_lock); + return true; + } + } + spin_unlock(&flctx->flc_lock); + return false; +} +EXPORT_SYMBOL_GPL(locks_owner_has_blockers); + /* Free a lock which is not in use. */ void locks_free_lock(struct file_lock *fl) { @@ -367,21 +425,9 @@ static inline int flock_translate_cmd(int cmd) { } /* Fill in a file_lock structure with an appropriate FLOCK lock. */ -static struct file_lock * -flock_make_lock(struct file *filp, unsigned int cmd, struct file_lock *fl) +static void flock_make_lock(struct file *filp, struct file_lock *fl, int type) { - int type = flock_translate_cmd(cmd); - - if (type < 0) - return ERR_PTR(type); - - if (fl == NULL) { - fl = locks_alloc_lock(); - if (fl == NULL) - return ERR_PTR(-ENOMEM); - } else { - locks_init_lock(fl); - } + locks_init_lock(fl); fl->fl_file = filp; fl->fl_owner = filp; @@ -389,8 +435,6 @@ flock_make_lock(struct file *filp, unsigned int cmd, struct file_lock *fl) fl->fl_flags = FL_FLOCK; fl->fl_type = type; fl->fl_end = OFFSET_MAX; - - return fl; } static int assign_type(struct file_lock *fl, long type) @@ -844,6 +888,8 @@ posix_test_lock(struct file *filp, struct file_lock *fl) struct file_lock *cfl; struct file_lock_context *ctx; struct inode *inode = locks_inode(filp); + void *owner; + void (*func)(void); ctx = smp_load_acquire(&inode->i_flctx); if (!ctx || list_empty_careful(&ctx->flc_posix)) { @@ -851,12 +897,23 @@ posix_test_lock(struct file *filp, struct file_lock *fl) return; } +retry: spin_lock(&ctx->flc_lock); list_for_each_entry(cfl, &ctx->flc_posix, fl_list) { - if (posix_locks_conflict(fl, cfl)) { - locks_copy_conflock(fl, cfl); - goto out; + if (!posix_locks_conflict(fl, cfl)) + continue; + if (cfl->fl_lmops && cfl->fl_lmops->lm_lock_expirable + && (*cfl->fl_lmops->lm_lock_expirable)(cfl)) { + owner = cfl->fl_lmops->lm_mod_owner; + func = cfl->fl_lmops->lm_expire_lock; + __module_get(owner); + spin_unlock(&ctx->flc_lock); + (*func)(); + module_put(owner); + goto retry; } + locks_copy_conflock(fl, cfl); + goto out; } fl->fl_type = F_UNLCK; out: @@ -1030,6 +1087,8 @@ static int posix_lock_inode(struct inode *inode, struct file_lock *request, int error; bool added = false; LIST_HEAD(dispose); + void *owner; + void (*func)(void); ctx = locks_get_lock_context(inode, request->fl_type); if (!ctx) @@ -1048,6 +1107,7 @@ static int posix_lock_inode(struct inode *inode, struct file_lock *request, new_fl2 = locks_alloc_lock(); } +retry: percpu_down_read(&file_rwsem); spin_lock(&ctx->flc_lock); /* @@ -1059,6 +1119,17 @@ static int posix_lock_inode(struct inode *inode, struct file_lock *request, list_for_each_entry(fl, &ctx->flc_posix, fl_list) { if (!posix_locks_conflict(request, fl)) continue; + if (fl->fl_lmops && fl->fl_lmops->lm_lock_expirable + && (*fl->fl_lmops->lm_lock_expirable)(fl)) { + owner = fl->fl_lmops->lm_mod_owner; + func = fl->fl_lmops->lm_expire_lock; + __module_get(owner); + spin_unlock(&ctx->flc_lock); + percpu_up_read(&file_rwsem); + (*func)(); + module_put(owner); + goto retry; + } if (conflock) locks_copy_conflock(conflock, fl); error = -EAGAIN; @@ -2012,21 +2083,9 @@ EXPORT_SYMBOL(locks_lock_inode_wait); */ SYSCALL_DEFINE2(flock, unsigned int, fd, unsigned int, cmd) { - struct fd f = fdget(fd); - struct file_lock *lock; - int can_sleep, unlock; - int error; - - error = -EBADF; - if (!f.file) - goto out; - - can_sleep = !(cmd & LOCK_NB); - cmd &= ~LOCK_NB; - unlock = (cmd == LOCK_UN); - - if (!unlock && !(f.file->f_mode & (FMODE_READ|FMODE_WRITE))) - goto out_putf; + int can_sleep, error, type; + struct file_lock fl; + struct fd f; /* * LOCK_MAND locks were broken for a long time in that they never @@ -2038,36 +2097,42 @@ SYSCALL_DEFINE2(flock, unsigned int, fd, unsigned int, cmd) */ if (cmd & LOCK_MAND) { pr_warn_once("Attempt to set a LOCK_MAND lock via flock(2). This support has been removed and the request ignored.\n"); - error = 0; - goto out_putf; + return 0; } - lock = flock_make_lock(f.file, cmd, NULL); - if (IS_ERR(lock)) { - error = PTR_ERR(lock); + type = flock_translate_cmd(cmd & ~LOCK_NB); + if (type < 0) + return type; + + error = -EBADF; + f = fdget(fd); + if (!f.file) + return error; + + if (type != F_UNLCK && !(f.file->f_mode & (FMODE_READ | FMODE_WRITE))) goto out_putf; - } - if (can_sleep) - lock->fl_flags |= FL_SLEEP; + flock_make_lock(f.file, &fl, type); - error = security_file_lock(f.file, lock->fl_type); + error = security_file_lock(f.file, fl.fl_type); if (error) - goto out_free; + goto out_putf; + + can_sleep = !(cmd & LOCK_NB); + if (can_sleep) + fl.fl_flags |= FL_SLEEP; if (f.file->f_op->flock) error = f.file->f_op->flock(f.file, - (can_sleep) ? F_SETLKW : F_SETLK, - lock); + (can_sleep) ? F_SETLKW : F_SETLK, + &fl); else - error = locks_lock_file_wait(f.file, lock); - - out_free: - locks_free_lock(lock); + error = locks_lock_file_wait(f.file, &fl); + locks_release_private(&fl); out_putf: fdput(f); - out: + return error; } @@ -2529,7 +2594,7 @@ locks_remove_flock(struct file *filp, struct file_lock_context *flctx) if (list_empty(&flctx->flc_flock)) return; - flock_make_lock(filp, LOCK_UN, &fl); + flock_make_lock(filp, &fl, F_UNLCK); fl.fl_flags |= FL_CLOSE; if (filp->f_op->flock) |