| From 5cc1fb2a093e254b656c64ff24b0b76bed1d34d9 Mon Sep 17 00:00:00 2001 |
| From: Oleg Drokin <green@linuxhacker.ru> |
| Date: Tue, 14 Jun 2016 23:28:05 -0400 |
| Subject: nfsd: Extend the mutex holding region around in nfsd4_process_open2() |
| |
| From: Oleg Drokin <green@linuxhacker.ru> |
| |
| commit 5cc1fb2a093e254b656c64ff24b0b76bed1d34d9 upstream. |
| |
| To avoid racing entry into nfs4_get_vfs_file(). |
| Make init_open_stateid() return with locked stateid to be unlocked |
| by the caller. |
| |
| 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 | 16 +++++++++++++--- |
| 1 file changed, 13 insertions(+), 3 deletions(-) |
| |
| --- a/fs/nfsd/nfs4state.c |
| +++ b/fs/nfsd/nfs4state.c |
| @@ -3452,6 +3452,10 @@ init_open_stateid(struct nfs4_ol_stateid |
| struct nfs4_openowner *oo = open->op_openowner; |
| struct nfs4_ol_stateid *retstp = NULL; |
| |
| + /* We are moving these outside of the spinlocks to avoid the warnings */ |
| + mutex_init(&stp->st_mutex); |
| + mutex_lock(&stp->st_mutex); |
| + |
| spin_lock(&oo->oo_owner.so_client->cl_lock); |
| spin_lock(&fp->fi_lock); |
| |
| @@ -3467,13 +3471,17 @@ init_open_stateid(struct nfs4_ol_stateid |
| stp->st_access_bmap = 0; |
| stp->st_deny_bmap = 0; |
| stp->st_openstp = NULL; |
| - mutex_init(&stp->st_mutex); |
| list_add(&stp->st_perstateowner, &oo->oo_owner.so_stateids); |
| list_add(&stp->st_perfile, &fp->fi_stateids); |
| |
| out_unlock: |
| spin_unlock(&fp->fi_lock); |
| spin_unlock(&oo->oo_owner.so_client->cl_lock); |
| + if (retstp) { |
| + mutex_lock(&retstp->st_mutex); |
| + /* Not that we need to, just for neatness */ |
| + mutex_unlock(&stp->st_mutex); |
| + } |
| return retstp; |
| } |
| |
| @@ -4309,11 +4317,14 @@ nfsd4_process_open2(struct svc_rqst *rqs |
| } 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; |
| - mutex_lock(&stp->st_mutex); |
| status = nfs4_upgrade_open(rqstp, fp, current_fh, |
| stp, open); |
| if (status) { |
| @@ -4322,7 +4333,6 @@ nfsd4_process_open2(struct svc_rqst *rqs |
| } |
| goto upgrade_out; |
| } |
| - mutex_lock(&stp->st_mutex); |
| status = nfs4_get_vfs_file(rqstp, fp, current_fh, stp, open); |
| if (status) { |
| mutex_unlock(&stp->st_mutex); |