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authorTrond Myklebust <Trond.Myklebust@netapp.com>2007-07-26 12:06:17 -0400
committerTrond Myklebust <Trond.Myklebust@netapp.com>2007-08-07 15:13:17 -0400
commit5e11934d13c9a3bcb0cadad6c7a7de5c32660422 (patch)
tree639e5660e9081bc16afccf0c509ff41c413b483d
parentb247bbf1da69ce376aa1ceb8057331214589e366 (diff)
downloadop-kernel-dev-5e11934d13c9a3bcb0cadad6c7a7de5c32660422.zip
op-kernel-dev-5e11934d13c9a3bcb0cadad6c7a7de5c32660422.tar.gz
NFS: Fix put_nfs_open_context
We need to grab the inode->i_lock atomically with the last reference put in order to remove the open context that is being freed from the nfsi->open_files list. Fix by converting the kref to a standard atomic counter and then using atomic_dec_and_lock()... Thanks to Arnd Bergmann for pointing out the problem. Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
-rw-r--r--fs/nfs/inode.c24
-rw-r--r--include/linux/nfs_fs.h2
2 files changed, 9 insertions, 17 deletions
diff --git a/fs/nfs/inode.c b/fs/nfs/inode.c
index bca6cdc..71a49c3 100644
--- a/fs/nfs/inode.c
+++ b/fs/nfs/inode.c
@@ -468,7 +468,7 @@ static struct nfs_open_context *alloc_nfs_open_context(struct vfsmount *mnt, str
ctx->lockowner = current->files;
ctx->error = 0;
ctx->dir_cookie = 0;
- kref_init(&ctx->kref);
+ atomic_set(&ctx->count, 1);
}
return ctx;
}
@@ -476,21 +476,18 @@ static struct nfs_open_context *alloc_nfs_open_context(struct vfsmount *mnt, str
struct nfs_open_context *get_nfs_open_context(struct nfs_open_context *ctx)
{
if (ctx != NULL)
- kref_get(&ctx->kref);
+ atomic_inc(&ctx->count);
return ctx;
}
-static void nfs_free_open_context(struct kref *kref)
+void put_nfs_open_context(struct nfs_open_context *ctx)
{
- struct nfs_open_context *ctx = container_of(kref,
- struct nfs_open_context, kref);
+ struct inode *inode = ctx->path.dentry->d_inode;
- if (!list_empty(&ctx->list)) {
- struct inode *inode = ctx->path.dentry->d_inode;
- spin_lock(&inode->i_lock);
- list_del(&ctx->list);
- spin_unlock(&inode->i_lock);
- }
+ if (!atomic_dec_and_lock(&ctx->count, &inode->i_lock))
+ return;
+ list_del(&ctx->list);
+ spin_unlock(&inode->i_lock);
if (ctx->state != NULL)
nfs4_close_state(&ctx->path, ctx->state, ctx->mode);
if (ctx->cred != NULL)
@@ -500,11 +497,6 @@ static void nfs_free_open_context(struct kref *kref)
kfree(ctx);
}
-void put_nfs_open_context(struct nfs_open_context *ctx)
-{
- kref_put(&ctx->kref, nfs_free_open_context);
-}
-
/*
* Ensure that mmap has a recent RPC credential for use when writing out
* shared pages
diff --git a/include/linux/nfs_fs.h b/include/linux/nfs_fs.h
index 9ba4aec..157dcb0 100644
--- a/include/linux/nfs_fs.h
+++ b/include/linux/nfs_fs.h
@@ -71,7 +71,7 @@ struct nfs_access_entry {
struct nfs4_state;
struct nfs_open_context {
- struct kref kref;
+ atomic_t count;
struct path path;
struct rpc_cred *cred;
struct nfs4_state *state;
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