[PATCH 3.19 101/175] NFSv4: Ensure we reference the inode for return-on-close in delegreturn

Greg Kroah-Hartman
2015-03-04T06:21:45Z

From: Trond Myklebust <trond.myklebust@primarydata.com>

commit ea7c38fef0b774a5dc16fb0ca5935f0ae8568176 upstream.

If we have to do a return-on-close in the delegreturn code, then
we must ensure that the inode and super block remain referenced.

Cc: Peng Tao <tao.peng@primarydata.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Reviewed-by: Peng Tao <tao.peng@primarydata.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
fs/nfs/internal.h | 22 +++++++++++++++++++++-
fs/nfs/nfs4proc.c | 14 +++++++++-----
fs/nfs/super.c | 9 ++++++---
3 files changed, 36 insertions(+), 9 deletions(-)

--- a/fs/nfs/internal.h
+++ b/fs/nfs/internal.h
@@ -375,7 +375,7 @@ extern struct rpc_stat nfs_rpcstat;

extern int __init register_nfs_fs(void);
extern void __exit unregister_nfs_fs(void);
-extern void nfs_sb_active(struct super_block *sb);
+extern bool nfs_sb_active(struct super_block *sb);
extern void nfs_sb_deactive(struct super_block *sb);

/* namespace.c */
@@ -493,6 +493,26 @@ extern int nfs41_walk_client_list(struct
struct nfs_client **result,
struct rpc_cred *cred);

+static inline struct inode *nfs_igrab_and_active(struct inode *inode)
+{
+ inode = igrab(inode);
+ if (inode != NULL && !nfs_sb_active(inode->i_sb)) {
+ iput(inode);
+ inode = NULL;
+ }
+ return inode;
+}
+
+static inline void nfs_iput_and_deactive(struct inode *inode)
+{
+ if (inode != NULL) {
+ struct super_block *sb = inode->i_sb;
+
+ iput(inode);
+ nfs_sb_deactive(sb);
+ }
+}
+
/*
* Determine the device name as a string
*/
--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -5137,9 +5137,13 @@ static void nfs4_delegreturn_done(struct
static void nfs4_delegreturn_release(void *calldata)
{
struct nfs4_delegreturndata *data = calldata;
+ struct inode *inode = data->inode;

- if (data->roc)
- pnfs_roc_release(data->inode);
+ if (inode) {
+ if (data->roc)
+ pnfs_roc_release(inode);
+ nfs_iput_and_deactive(inode);
+ }
kfree(calldata);
}

@@ -5196,9 +5200,9 @@ static int _nfs4_proc_delegreturn(struct
nfs_fattr_init(data->res.fattr);
data->timestamp = jiffies;
data->rpc_status = 0;
- data->inode = inode;
- data->roc = list_empty(&NFS_I(inode)->open_files) ?
- pnfs_roc(inode) : false;
+ data->inode = nfs_igrab_and_active(inode);
+ if (data->inode)
+ data->roc = nfs4_roc(inode);

task_setup_data.callback_data = data;
msg.rpc_argp = &data->args;
--- a/fs/nfs/super.c
+++ b/fs/nfs/super.c
@@ -405,12 +405,15 @@ void __exit unregister_nfs_fs(void)
unregister_filesystem(&nfs_fs_type);
}

-void nfs_sb_active(struct super_block *sb)
+bool nfs_sb_active(struct super_block *sb)
{
struct nfs_server *server = NFS_SB(sb);

- if (atomic_inc_return(&server->active) == 1)
- atomic_inc(&sb->s_active);
+ if (!atomic_inc_not_zero(&sb->s_active))
+ return false;
+ if (atomic_inc_return(&server->active) != 1)
+ atomic_dec(&sb->s_active);
+ return true;
}
EXPORT_SYMBOL_GPL(nfs_sb_active);