From: Jeff Layton jlayton@kernel.org
[ Upstream commit ab1ddef98a715eddb65309ffa83267e4e84a571e ]
Ceph has a need to know whether a particular inode has any locks set on it. It's currently tracking that by a num_locks field in its filp->private_data, but that's problematic as it tries to decrement this field when releasing locks and that can race with the file being torn down.
Add a new vfs_inode_has_locks helper that just returns whether any locks are currently held on the inode.
Reviewed-by: Xiubo Li xiubli@redhat.com Reviewed-by: Christoph Hellwig hch@infradead.org Signed-off-by: Jeff Layton jlayton@kernel.org Stable-dep-of: 461ab10ef7e6 ("ceph: switch to vfs_inode_has_locks() to fix file lock bug") Signed-off-by: Sasha Levin sashal@kernel.org --- fs/locks.c | 23 +++++++++++++++++++++++ include/linux/fs.h | 6 ++++++ 2 files changed, 29 insertions(+)
diff --git a/fs/locks.c b/fs/locks.c index 3d6fb4ae847b..82a4487e95b3 100644 --- a/fs/locks.c +++ b/fs/locks.c @@ -2703,6 +2703,29 @@ int vfs_cancel_lock(struct file *filp, struct file_lock *fl) } EXPORT_SYMBOL_GPL(vfs_cancel_lock);
+/** + * vfs_inode_has_locks - are any file locks held on @inode? + * @inode: inode to check for locks + * + * Return true if there are any FL_POSIX or FL_FLOCK locks currently + * set on @inode. + */ +bool vfs_inode_has_locks(struct inode *inode) +{ + struct file_lock_context *ctx; + bool ret; + + ctx = smp_load_acquire(&inode->i_flctx); + if (!ctx) + return false; + + spin_lock(&ctx->flc_lock); + ret = !list_empty(&ctx->flc_posix) || !list_empty(&ctx->flc_flock); + spin_unlock(&ctx->flc_lock); + return ret; +} +EXPORT_SYMBOL_GPL(vfs_inode_has_locks); + #ifdef CONFIG_PROC_FS #include <linux/proc_fs.h> #include <linux/seq_file.h> diff --git a/include/linux/fs.h b/include/linux/fs.h index 68fcf3ec9cf6..1e1ac116dd13 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -1195,6 +1195,7 @@ extern int locks_delete_block(struct file_lock *); extern int vfs_test_lock(struct file *, struct file_lock *); extern int vfs_lock_file(struct file *, unsigned int, struct file_lock *, struct file_lock *); extern int vfs_cancel_lock(struct file *filp, struct file_lock *fl); +bool vfs_inode_has_locks(struct inode *inode); extern int locks_lock_inode_wait(struct inode *inode, struct file_lock *fl); extern int __break_lease(struct inode *inode, unsigned int flags, unsigned int type); extern void lease_get_mtime(struct inode *, struct timespec64 *time); @@ -1307,6 +1308,11 @@ static inline int vfs_cancel_lock(struct file *filp, struct file_lock *fl) return 0; }
+static inline bool vfs_inode_has_locks(struct inode *inode) +{ + return false; +} + static inline int locks_lock_inode_wait(struct inode *inode, struct file_lock *fl) { return -ENOLCK;