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Subject[PATCH 4.4 25/27] nfsd: Make init_open_stateid() a bit more whole
Date
4.4-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Oleg Drokin <green@linuxhacker.ru>

commit 8c7245abda877d4689b3371db8ae2a4400d7d9ce upstream.

Move the state selection logic inside from the caller,
always making it return correct stp to use.

Signed-off-by: J . Bruce Fields <bfields@fieldses.org>
Signed-off-by: Oleg Drokin <green@linuxhacker.ru>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
fs/nfsd/nfs4state.c | 27 ++++++++++++---------------
1 file changed, 12 insertions(+), 15 deletions(-)

--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -3420,13 +3420,14 @@ alloc_init_open_stateowner(unsigned int
}

static struct nfs4_ol_stateid *
-init_open_stateid(struct nfs4_ol_stateid *stp, struct nfs4_file *fp,
- struct nfsd4_open *open)
+init_open_stateid(struct nfs4_file *fp, struct nfsd4_open *open)
{

struct nfs4_openowner *oo = open->op_openowner;
struct nfs4_ol_stateid *retstp = NULL;
+ struct nfs4_ol_stateid *stp;

+ stp = open->op_stp;
/* We are moving these outside of the spinlocks to avoid the warnings */
mutex_init(&stp->st_mutex);
mutex_lock(&stp->st_mutex);
@@ -3437,6 +3438,8 @@ init_open_stateid(struct nfs4_ol_stateid
retstp = nfsd4_find_existing_open(fp, open);
if (retstp)
goto out_unlock;
+
+ open->op_stp = NULL;
atomic_inc(&stp->st_stid.sc_count);
stp->st_stid.sc_type = NFS4_OPEN_STID;
INIT_LIST_HEAD(&stp->st_locks);
@@ -3454,10 +3457,11 @@ out_unlock:
spin_unlock(&oo->oo_owner.so_client->cl_lock);
if (retstp) {
mutex_lock(&retstp->st_mutex);
- /* Not that we need to, just for neatness */
+ /* To keep mutex tracking happy */
mutex_unlock(&stp->st_mutex);
+ stp = retstp;
}
- return retstp;
+ return stp;
}

/*
@@ -4260,7 +4264,6 @@ nfsd4_process_open2(struct svc_rqst *rqs
struct nfs4_client *cl = open->op_openowner->oo_owner.so_client;
struct nfs4_file *fp = NULL;
struct nfs4_ol_stateid *stp = NULL;
- struct nfs4_ol_stateid *swapstp = NULL;
struct nfs4_delegation *dp = NULL;
__be32 status;

@@ -4297,16 +4300,10 @@ nfsd4_process_open2(struct svc_rqst *rqs
goto out;
}
} else {
- stp = open->op_stp;
- open->op_stp = NULL;
- /*
- * init_open_stateid() either returns a locked stateid
- * it found, or initializes and locks the new one we passed in
- */
- swapstp = init_open_stateid(stp, fp, open);
- if (swapstp) {
- nfs4_put_stid(&stp->st_stid);
- stp = swapstp;
+ /* stp is returned locked. */
+ stp = init_open_stateid(fp, open);
+ /* See if we lost the race to some other thread */
+ if (stp->st_access_bmap != 0) {
status = nfs4_upgrade_open(rqstp, fp, current_fh,
stp, open);
if (status) {

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