From: Trond Myklebust trond.myklebust@hammerspace.com
stable inclusion from linux-4.19.169 commit df7adeee7477c865fecdd43b55aee6cca0e9bb0a
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commit 896567ee7f17a8a736cda8a28cc987228410a2ac upstream.
Before referencing the inode, we must ensure that the superblock can be referenced. Otherwise, we can end up with iput() calling superblock operations that are no longer valid or accessible.
Fixes: ea7c38fef0b7 ("NFSv4: Ensure we reference the inode for return-on-close in delegreturn") Signed-off-by: Trond Myklebust trond.myklebust@hammerspace.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Yang Yingliang yangyingliang@huawei.com Signed-off-by: Cheng Jian cj.chengjian@huawei.com --- fs/nfs/internal.h | 12 +++++++----- 1 file changed, 7 insertions(+), 5 deletions(-)
diff --git a/fs/nfs/internal.h b/fs/nfs/internal.h index 8357ff69962f..cc07189a501f 100644 --- a/fs/nfs/internal.h +++ b/fs/nfs/internal.h @@ -575,12 +575,14 @@ extern int nfs4_test_session_trunk(struct rpc_clnt *,
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; + struct super_block *sb = inode->i_sb; + + if (sb && nfs_sb_active(sb)) { + if (igrab(inode)) + return inode; + nfs_sb_deactive(sb); } - return inode; + return NULL; }
static inline void nfs_iput_and_deactive(struct inode *inode)