From 5e11934d13c9a3bcb0cadad6c7a7de5c32660422 Mon Sep 17 00:00:00 2001 From: Trond Myklebust Date: Thu, 26 Jul 2007 12:06:17 -0400 Subject: 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 --- fs/nfs/inode.c | 24 ++++++++---------------- include/linux/nfs_fs.h | 2 +- 2 files changed, 9 insertions(+), 17 deletions(-) diff --git a/fs/nfs/inode.c b/fs/nfs/inode.c index bca6cdcb9f0d..71a49c3acabd 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 9ba4aec37c50..157dcb055b5c 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; -- cgit v1.2.1