From b4b7ff4b08e691656c9d77c758fc355833128ac0 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Andr=C3=A9=20Fabian=20Silva=20Delgado?= Date: Wed, 20 Jan 2016 14:01:31 -0300 Subject: Linux-libre 4.4-gnu --- fs/locks.c | 106 ++++++++++++++++++++++++++++++++++++++----------------------- 1 file changed, 67 insertions(+), 39 deletions(-) (limited to 'fs/locks.c') diff --git a/fs/locks.c b/fs/locks.c index 2a54c800a..0d2b3267e 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; @@ -1167,10 +1171,9 @@ EXPORT_SYMBOL(posix_lock_file); * @inode: inode of file to which lock request should be applied * @fl: The lock to be applied * - * Variant of posix_lock_file_wait that does not take a filp, and so can be - * used after the filp has already been torn down. + * Apply a POSIX style lock request to an inode. */ -int posix_lock_inode_wait(struct inode *inode, struct file_lock *fl) +static int posix_lock_inode_wait(struct inode *inode, struct file_lock *fl) { int error; might_sleep (); @@ -1187,7 +1190,6 @@ int posix_lock_inode_wait(struct inode *inode, struct file_lock *fl) } return error; } -EXPORT_SYMBOL(posix_lock_inode_wait); /** * locks_mandatory_locked - Check for an active lock @@ -1203,7 +1205,7 @@ 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 +1390,7 @@ 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 +1402,7 @@ 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 +1497,10 @@ 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 +1547,11 @@ 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); @@ -1711,11 +1716,11 @@ static int generic_delete_lease(struct file *filp, void *owner) { int error = -EAGAIN; 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 inode *inode = file_inode(filp); + 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; @@ -1751,8 +1756,7 @@ static int generic_delete_lease(struct file *filp, void *owner) int generic_setlease(struct file *filp, long arg, struct file_lock **flp, void **priv) { - struct dentry *dentry = filp->f_path.dentry; - struct inode *inode = dentry->d_inode; + struct inode *inode = file_inode(filp); int error; if ((!uid_eq(current_fsuid(), inode->i_uid)) && !capable(CAP_LEASE)) @@ -1856,7 +1860,7 @@ int fcntl_setlease(unsigned int fd, struct file *filp, long arg) * * Apply a FLOCK style lock request to an inode. */ -int flock_lock_inode_wait(struct inode *inode, struct file_lock *fl) +static int flock_lock_inode_wait(struct inode *inode, struct file_lock *fl) { int error; might_sleep(); @@ -1873,7 +1877,30 @@ int flock_lock_inode_wait(struct inode *inode, struct file_lock *fl) } return error; } -EXPORT_SYMBOL(flock_lock_inode_wait); + +/** + * locks_lock_inode_wait - Apply a lock to an inode + * @inode: inode of the file to apply to + * @fl: The lock to be applied + * + * Apply a POSIX or FLOCK style lock request to an inode. + */ +int locks_lock_inode_wait(struct inode *inode, struct file_lock *fl) +{ + int res = 0; + switch (fl->fl_flags & (FL_POSIX|FL_FLOCK)) { + case FL_POSIX: + res = posix_lock_inode_wait(inode, fl); + break; + case FL_FLOCK: + res = flock_lock_inode_wait(inode, fl); + break; + default: + BUG(); + } + return res; +} +EXPORT_SYMBOL(locks_lock_inode_wait); /** * sys_flock: - flock() system call. @@ -1931,7 +1958,7 @@ SYSCALL_DEFINE2(flock, unsigned int, fd, unsigned int, cmd) (can_sleep) ? F_SETLKW : F_SETLK, lock); else - error = flock_lock_file_wait(f.file, lock); + error = locks_lock_file_wait(f.file, lock); out_free: locks_free_lock(lock); @@ -2107,7 +2134,7 @@ static int do_lock_file_wait(struct file *filp, unsigned int cmd, return error; } -/* Ensure that fl->fl_filp has compatible f_mode for F_SETLK calls */ +/* Ensure that fl->fl_file has compatible f_mode for F_SETLK calls */ static int check_fmode_for_setlk(struct file_lock *fl) { @@ -2359,13 +2386,14 @@ 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 +2417,7 @@ 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 +2428,6 @@ 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 +2443,8 @@ 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 +2464,20 @@ 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 +2644,7 @@ 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; -- cgit v1.2.3