diff options
| -rw-r--r-- | fs/locks.c | 63 |
1 files changed, 36 insertions, 27 deletions
diff --git a/fs/locks.c b/fs/locks.c index 2a54c800a223..316e474c5fdb 100644 --- a/fs/locks.c +++ b/fs/locks.c @@ -205,28 +205,32 @@ static struct kmem_cache *filelock_cache __read_mostly; static struct file_lock_context * locks_get_lock_context(struct inode *inode, int type) { - struct file_lock_context *new; + struct file_lock_context *ctx; - if (likely(inode->i_flctx) || type == F_UNLCK) + /* paired with cmpxchg() below */ + ctx = smp_load_acquire(&inode->i_flctx); + if (likely(ctx) || type == F_UNLCK) goto out; - new = kmem_cache_alloc(flctx_cache, GFP_KERNEL); - if (!new) + ctx = kmem_cache_alloc(flctx_cache, GFP_KERNEL); + if (!ctx) goto out; - spin_lock_init(&new->flc_lock); - INIT_LIST_HEAD(&new->flc_flock); - INIT_LIST_HEAD(&new->flc_posix); - INIT_LIST_HEAD(&new->flc_lease); + spin_lock_init(&ctx->flc_lock); + INIT_LIST_HEAD(&ctx->flc_flock); + INIT_LIST_HEAD(&ctx->flc_posix); + INIT_LIST_HEAD(&ctx->flc_lease); /* * Assign the pointer if it's not already assigned. If it is, then * free the context we just allocated. */ - if (cmpxchg(&inode->i_flctx, NULL, new)) - kmem_cache_free(flctx_cache, new); + if (cmpxchg(&inode->i_flctx, NULL, ctx)) { + kmem_cache_free(flctx_cache, ctx); + ctx = smp_load_acquire(&inode->i_flctx); + } out: - return inode->i_flctx; + return ctx; } void @@ -762,7 +766,7 @@ posix_test_lock(struct file *filp, struct file_lock *fl) struct file_lock_context *ctx; struct inode *inode = file_inode(filp); - ctx = inode->i_flctx; + ctx = smp_load_acquire(&inode->i_flctx); if (!ctx || list_empty_careful(&ctx->flc_posix)) { fl->fl_type = F_UNLCK; return; @@ -1203,7 +1207,7 @@ int locks_mandatory_locked(struct file *file) struct file_lock_context *ctx; struct file_lock *fl; - ctx = inode->i_flctx; + ctx = smp_load_acquire(&inode->i_flctx); if (!ctx || list_empty_careful(&ctx->flc_posix)) return 0; @@ -1388,7 +1392,7 @@ any_leases_conflict(struct inode *inode, struct file_lock *breaker) int __break_lease(struct inode *inode, unsigned int mode, unsigned int type) { int error = 0; - struct file_lock_context *ctx = inode->i_flctx; + struct file_lock_context *ctx; struct file_lock *new_fl, *fl, *tmp; unsigned long break_time; int want_write = (mode & O_ACCMODE) != O_RDONLY; @@ -1400,6 +1404,7 @@ int __break_lease(struct inode *inode, unsigned int mode, unsigned int type) new_fl->fl_flags = type; /* typically we will check that ctx is non-NULL before calling */ + ctx = smp_load_acquire(&inode->i_flctx); if (!ctx) { WARN_ON_ONCE(1); return error; @@ -1494,9 +1499,10 @@ EXPORT_SYMBOL(__break_lease); void lease_get_mtime(struct inode *inode, struct timespec *time) { bool has_lease = false; - struct file_lock_context *ctx = inode->i_flctx; + struct file_lock_context *ctx; struct file_lock *fl; + ctx = smp_load_acquire(&inode->i_flctx); if (ctx && !list_empty_careful(&ctx->flc_lease)) { spin_lock(&ctx->flc_lock); if (!list_empty(&ctx->flc_lease)) { @@ -1543,10 +1549,11 @@ int fcntl_getlease(struct file *filp) { struct file_lock *fl; struct inode *inode = file_inode(filp); - struct file_lock_context *ctx = inode->i_flctx; + struct file_lock_context *ctx; int type = F_UNLCK; LIST_HEAD(dispose); + ctx = smp_load_acquire(&inode->i_flctx); if (ctx && !list_empty_careful(&ctx->flc_lease)) { spin_lock(&ctx->flc_lock); time_out_leases(file_inode(filp), &dispose); @@ -1713,9 +1720,10 @@ static int generic_delete_lease(struct file *filp, void *owner) struct file_lock *fl, *victim = NULL; struct dentry *dentry = filp->f_path.dentry; struct inode *inode = dentry->d_inode; - struct file_lock_context *ctx = inode->i_flctx; + struct file_lock_context *ctx; LIST_HEAD(dispose); + ctx = smp_load_acquire(&inode->i_flctx); if (!ctx) { trace_generic_delete_lease(inode, NULL); return error; @@ -2359,13 +2367,14 @@ out: void locks_remove_posix(struct file *filp, fl_owner_t owner) { struct file_lock lock; - struct file_lock_context *ctx = file_inode(filp)->i_flctx; + struct file_lock_context *ctx; /* * 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. */ + ctx = smp_load_acquire(&file_inode(filp)->i_flctx); if (!ctx || list_empty(&ctx->flc_posix)) return; @@ -2389,7 +2398,7 @@ EXPORT_SYMBOL(locks_remove_posix); /* The i_flctx must be valid when calling into here */ static void -locks_remove_flock(struct file *filp) +locks_remove_flock(struct file *filp, struct file_lock_context *flctx) { struct file_lock fl = { .fl_owner = filp, @@ -2400,7 +2409,6 @@ locks_remove_flock(struct file *filp) .fl_end = OFFSET_MAX, }; struct inode *inode = file_inode(filp); - struct file_lock_context *flctx = inode->i_flctx; if (list_empty(&flctx->flc_flock)) return; @@ -2416,10 +2424,8 @@ locks_remove_flock(struct file *filp) /* The i_flctx must be valid when calling into here */ static void -locks_remove_lease(struct file *filp) +locks_remove_lease(struct file *filp, struct file_lock_context *ctx) { - struct inode *inode = file_inode(filp); - struct file_lock_context *ctx = inode->i_flctx; struct file_lock *fl, *tmp; LIST_HEAD(dispose); @@ -2439,17 +2445,20 @@ locks_remove_lease(struct file *filp) */ void locks_remove_file(struct file *filp) { - if (!file_inode(filp)->i_flctx) + struct file_lock_context *ctx; + + ctx = smp_load_acquire(&file_inode(filp)->i_flctx); + if (!ctx) return; /* remove any OFD locks */ locks_remove_posix(filp, filp); /* remove flock locks */ - locks_remove_flock(filp); + locks_remove_flock(filp, ctx); /* remove any leases */ - locks_remove_lease(filp); + locks_remove_lease(filp, ctx); } /** @@ -2616,7 +2625,7 @@ void show_fd_locks(struct seq_file *f, struct file_lock_context *ctx; int id = 0; - ctx = inode->i_flctx; + ctx = smp_load_acquire(&inode->i_flctx); if (!ctx) return; |