From: Trond Myklebust Date: Wed, 30 May 2007 12:58:00 -0400 NFS: Fix a refcount leakage in O_DIRECT The current code is leaking a reference to dreq->kref when the calls to nfs_direct_read_schedule() and nfs_direct_write_schedule() return an error. This patch moves the call to kref_put() from nfs_direct_wait() back into nfs_direct_read() and nfs_direct_write() (which are the functions that actually took the reference in the first place) fixing the leak. Thanks to Denis V. Lunev for spotting the bug and proposing the original fix. Acked-by: Denis V. Lunev Acked-by: Chuck Lever Signed-off-by: Trond Myklebust --- fs/nfs/direct.c | 12 +++++++++--- 1 files changed, 9 insertions(+), 3 deletions(-) diff --git a/fs/nfs/direct.c b/fs/nfs/direct.c index 0c542ec..00eee87 100644 --- a/fs/nfs/direct.c +++ b/fs/nfs/direct.c @@ -168,7 +168,7 @@ static inline struct nfs_direct_req *nfs_direct_req_alloc(void) return dreq; } -static void nfs_direct_req_release(struct kref *kref) +static void nfs_direct_req_free(struct kref *kref) { struct nfs_direct_req *dreq = container_of(kref, struct nfs_direct_req, kref); @@ -177,6 +177,11 @@ static void nfs_direct_req_release(struct kref *kref) kmem_cache_free(nfs_direct_cachep, dreq); } +static void nfs_direct_req_release(struct nfs_direct_req *dreq) +{ + kref_put(&dreq->kref, nfs_direct_req_free); +} + /* * Collects and returns the final error value/byte-count. */ @@ -196,7 +201,6 @@ static ssize_t nfs_direct_wait(struct nfs_direct_req *dreq) result = dreq->count; out: - kref_put(&dreq->kref, nfs_direct_req_release); return (ssize_t) result; } @@ -214,7 +218,7 @@ static void nfs_direct_complete(struct nfs_direct_req *dreq) } complete_all(&dreq->completion); - kref_put(&dreq->kref, nfs_direct_req_release); + nfs_direct_req_release(dreq); } /* @@ -369,6 +373,7 @@ static ssize_t nfs_direct_read(struct kiocb *iocb, unsigned long user_addr, size if (!result) result = nfs_direct_wait(dreq); rpc_clnt_sigunmask(clnt, &oldset); + nfs_direct_req_release(dreq); return result; } @@ -716,6 +721,7 @@ static ssize_t nfs_direct_write(struct kiocb *iocb, unsigned long user_addr, siz if (!result) result = nfs_direct_wait(dreq); rpc_clnt_sigunmask(clnt, &oldset); + nfs_direct_req_release(dreq); return result; }