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authorJeff Layton <jlayton@primarydata.com>2015-01-16 15:05:54 -0500
committerJeff Layton <jlayton@primarydata.com>2015-01-16 15:05:54 -0500
commit4a075e39c86490cc0f0c10ac6abe3592d1689463 (patch)
tree8da8633f9f717128c02a08ad15b7d9f067091acb /fs
parentdd459bb1974c5e9cff3dfbf4f6fdb3e9363ef32e (diff)
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>
Diffstat (limited to 'fs')
-rw-r--r--fs/inode.c3
-rw-r--r--fs/locks.c44
2 files changed, 46 insertions, 1 deletions
diff --git a/fs/inode.c b/fs/inode.c
index aa149e7262ac..f30872ade6d7 100644
--- a/fs/inode.c
+++ b/fs/inode.c
@@ -194,7 +194,7 @@ int inode_init_always(struct super_block *sb, struct inode *inode)
#ifdef CONFIG_FSNOTIFY
inode->i_fsnotify_mask = 0;
#endif
-
+ inode->i_flctx = NULL;
this_cpu_inc(nr_inodes);
return 0;
@@ -237,6 +237,7 @@ void __destroy_inode(struct inode *inode)
BUG_ON(inode_has_buffers(inode));
security_inode_free(inode);
fsnotify_inode_delete(inode);
+ locks_free_lock_context(inode->i_flctx);
if (!inode->i_nlink) {
WARN_ON(atomic_long_read(&inode->i_sb->s_remove_count) == 0);
atomic_long_dec(&inode->i_sb->s_remove_count);
diff --git a/fs/locks.c b/fs/locks.c
index ae1e7cf721d6..526d5fca67c8 100644
--- a/fs/locks.c
+++ b/fs/locks.c
@@ -202,8 +202,49 @@ static DEFINE_HASHTABLE(blocked_hash, BLOCKED_HASH_BITS);
*/
static DEFINE_SPINLOCK(blocked_lock_lock);
+static struct kmem_cache *flctx_cache __read_mostly;
static struct kmem_cache *filelock_cache __read_mostly;
+static struct file_lock_context *
+locks_get_lock_context(struct inode *inode)
+{
+ struct file_lock_context *new;
+
+ if (likely(inode->i_flctx))
+ goto out;
+
+ new = kmem_cache_alloc(flctx_cache, GFP_KERNEL);
+ if (!new)
+ goto out;
+
+ INIT_LIST_HEAD(&new->flc_flock);
+
+ /*
+ * Assign the pointer if it's not already assigned. If it is, then
+ * free the context we just allocated.
+ */
+ spin_lock(&inode->i_lock);
+ if (likely(!inode->i_flctx)) {
+ inode->i_flctx = new;
+ new = NULL;
+ }
+ spin_unlock(&inode->i_lock);
+
+ if (new)
+ kmem_cache_free(flctx_cache, new);
+out:
+ return inode->i_flctx;
+}
+
+void
+locks_free_lock_context(struct file_lock_context *ctx)
+{
+ if (ctx) {
+ WARN_ON_ONCE(!list_empty(&ctx->flc_flock));
+ kmem_cache_free(flctx_cache, ctx);
+ }
+}
+
static void locks_init_lock_heads(struct file_lock *fl)
{
INIT_HLIST_NODE(&fl->fl_link);
@@ -2636,6 +2677,9 @@ static int __init filelock_init(void)
{
int i;
+ flctx_cache = kmem_cache_create("file_lock_ctx",
+ sizeof(struct file_lock_context), 0, SLAB_PANIC, NULL);
+
filelock_cache = kmem_cache_create("file_lock_cache",
sizeof(struct file_lock), 0, SLAB_PANIC, NULL);

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