locks: add a new struct file_locking_context pointer to struct inode
The current scheme of using the i_flock list is really difficult to
manage. There is also a legitimate desire for a per-inode spinlock to
manage these lists that isn't the i_lock.
Start conversion to a new scheme to eventually replace the old i_flock
list with a new "file_lock_context" object.
We start by adding a new i_flctx to struct inode. For now, it lives in
parallel with i_flock list, but will eventually replace it. The idea is
to allocate a structure to sit in that pointer and act as a locus for
all things file locking.
We allocate a file_lock_context for an inode when the first lock is
added to it, and it's only freed when the inode is freed. We use the
i_lock to protect the assignment, but afterward it should mostly be
accessed locklessly.
Signed-off-by: Jeff Layton <jlayton@primarydata.com>
Acked-by: Christoph Hellwig <hch@lst.de>
diff --git a/include/linux/fs.h b/include/linux/fs.h
index cd68181..dec0d38 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -626,6 +626,7 @@
#endif
const struct file_operations *i_fop; /* former ->i_op->default_file_ops */
struct file_lock *i_flock;
+ struct file_lock_context *i_flctx;
struct address_space i_data;
struct list_head i_devices;
union {
@@ -965,6 +966,10 @@
} fl_u;
};
+struct file_lock_context {
+ struct list_head flc_flock;
+};
+
/* The following constant reflects the upper bound of the file/locking space */
#ifndef OFFSET_MAX
#define INT_LIMIT(x) (~((x)1 << (sizeof(x)*8 - 1)))
@@ -991,6 +996,7 @@
extern int fcntl_getlease(struct file *filp);
/* fs/locks.c */
+void locks_free_lock_context(struct file_lock_context *ctx);
void locks_free_lock(struct file_lock *fl);
extern void locks_init_lock(struct file_lock *);
extern struct file_lock * locks_alloc_lock(void);
@@ -1048,6 +1054,11 @@
return F_UNLCK;
}
+static inline void
+locks_free_lock_context(struct file_lock_context *ctx)
+{
+}
+
static inline void locks_init_lock(struct file_lock *fl)
{
return;