NFS/pnfs: Reference the layout cred in pnfs_prepare_layoutreturn()

When we're sending a layoutreturn, ensure that we reference the
layout cred atomically with the copy of the stateid.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
index e4f8311..99e9f2e 100644 (file)
--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -9297,6 +9297,7 @@ static void nfs4_layoutreturn_release(void *calldata)
                lrp->ld_private.ops->free(&lrp->ld_private);
        pnfs_put_layout_hdr(lrp->args.layout);
        nfs_iput_and_deactive(lrp->inode);
+       put_cred(lrp->cred);
        kfree(calldata);
        dprintk("<-- %s\n", __func__);
 }

diff --git a/fs/nfs/pnfs.c b/fs/nfs/pnfs.c
index 84029c9..f2dc35c 100644 (file)
--- a/fs/nfs/pnfs.c
+++ b/fs/nfs/pnfs.c
@@ -1144,6 +1144,7 @@ out_unlock:
 static bool
 pnfs_prepare_layoutreturn(struct pnfs_layout_hdr *lo,
                nfs4_stateid *stateid,
+               const struct cred **cred,
                enum pnfs_iomode *iomode)
 {
        /* Serialise LAYOUTGET/LAYOUTRETURN */
@@ -1154,18 +1155,17 @@ pnfs_prepare_layoutreturn(struct pnfs_layout_hdr *lo,
        set_bit(NFS_LAYOUT_RETURN, &lo->plh_flags);
        pnfs_get_layout_hdr(lo);
        if (test_bit(NFS_LAYOUT_RETURN_REQUESTED, &lo->plh_flags)) {
-               if (stateid != NULL) {
-                       nfs4_stateid_copy(stateid, &lo->plh_stateid);
-                       if (lo->plh_return_seq != 0)
-                               stateid->seqid = cpu_to_be32(lo->plh_return_seq);
-               }
+               nfs4_stateid_copy(stateid, &lo->plh_stateid);
+               *cred = get_cred(lo->plh_lc_cred);
+               if (lo->plh_return_seq != 0)
+                       stateid->seqid = cpu_to_be32(lo->plh_return_seq);
                if (iomode != NULL)
                        *iomode = lo->plh_return_iomode;
                pnfs_clear_layoutreturn_info(lo);
                return true;
        }
-       if (stateid != NULL)
-               nfs4_stateid_copy(stateid, &lo->plh_stateid);
+       nfs4_stateid_copy(stateid, &lo->plh_stateid);
+       *cred = get_cred(lo->plh_lc_cred);
        if (iomode != NULL)
                *iomode = IOMODE_ANY;
        return true;
@@ -1189,20 +1189,26 @@ pnfs_init_layoutreturn_args(struct nfs4_layoutreturn_args *args,
 }
 
 static int
-pnfs_send_layoutreturn(struct pnfs_layout_hdr *lo, const nfs4_stateid *stateid,
-                      enum pnfs_iomode iomode, bool sync)
+pnfs_send_layoutreturn(struct pnfs_layout_hdr *lo,
+                      const nfs4_stateid *stateid,
+                      const struct cred **pcred,
+                      enum pnfs_iomode iomode,
+                      bool sync)
 {
        struct inode *ino = lo->plh_inode;
        struct pnfs_layoutdriver_type *ld = NFS_SERVER(ino)->pnfs_curr_ld;
        struct nfs4_layoutreturn *lrp;
+       const struct cred *cred = *pcred;
        int status = 0;
 
+       *pcred = NULL;
        lrp = kzalloc(sizeof(*lrp), GFP_NOFS);
        if (unlikely(lrp == NULL)) {
                status = -ENOMEM;
                spin_lock(&ino->i_lock);
                pnfs_clear_layoutreturn_waitbit(lo);
                spin_unlock(&ino->i_lock);
+               put_cred(cred);
                pnfs_put_layout_hdr(lo);
                goto out;
        }
@@ -1210,7 +1216,7 @@ pnfs_send_layoutreturn(struct pnfs_layout_hdr *lo, const nfs4_stateid *stateid,
        pnfs_init_layoutreturn_args(&lrp->args, lo, stateid, iomode);
        lrp->args.ld_private = &lrp->ld_private;
        lrp->clp = NFS_SERVER(ino)->nfs_client;
-       lrp->cred = lo->plh_lc_cred;
+       lrp->cred = cred;
        if (ld->prepare_layoutreturn)
                ld->prepare_layoutreturn(&lrp->args);
 
@@ -1255,15 +1261,16 @@ static void pnfs_layoutreturn_before_put_layout_hdr(struct pnfs_layout_hdr *lo)
                return;
        spin_lock(&inode->i_lock);
        if (pnfs_layout_need_return(lo)) {
+               const struct cred *cred;
                nfs4_stateid stateid;
                enum pnfs_iomode iomode;
                bool send;
 
-               send = pnfs_prepare_layoutreturn(lo, &stateid, &iomode);
+               send = pnfs_prepare_layoutreturn(lo, &stateid, &cred, &iomode);
                spin_unlock(&inode->i_lock);
                if (send) {
                        /* Send an async layoutreturn so we dont deadlock */
-                       pnfs_send_layoutreturn(lo, &stateid, iomode, false);
+                       pnfs_send_layoutreturn(lo, &stateid, &cred, iomode, false);
                }
        } else
                spin_unlock(&inode->i_lock);
@@ -1283,6 +1290,7 @@ _pnfs_return_layout(struct inode *ino)
        struct pnfs_layout_hdr *lo = NULL;
        struct nfs_inode *nfsi = NFS_I(ino);
        LIST_HEAD(tmp_list);
+       const struct cred *cred;
        nfs4_stateid stateid;
        int status = 0;
        bool send, valid_layout;
@@ -1327,10 +1335,10 @@ _pnfs_return_layout(struct inode *ino)
                goto out_put_layout_hdr;
        }
 
-       send = pnfs_prepare_layoutreturn(lo, &stateid, NULL);
+       send = pnfs_prepare_layoutreturn(lo, &stateid, &cred, NULL);
        spin_unlock(&ino->i_lock);
        if (send)
-               status = pnfs_send_layoutreturn(lo, &stateid, IOMODE_ANY, true);
+               status = pnfs_send_layoutreturn(lo, &stateid, &cred, IOMODE_ANY, true);
 out_put_layout_hdr:
        pnfs_free_lseg_list(&tmp_list);
        pnfs_put_layout_hdr(lo);
@@ -1376,6 +1384,7 @@ bool pnfs_roc(struct inode *ino,
        struct nfs4_state *state;
        struct pnfs_layout_hdr *lo;
        struct pnfs_layout_segment *lseg, *next;
+       const struct cred *lc_cred;
        nfs4_stateid stateid;
        enum pnfs_iomode iomode = 0;
        bool layoutreturn = false, roc = false;
@@ -1445,16 +1454,20 @@ retry:
         * 2. we don't send layoutreturn
         */
        /* lo ref dropped in pnfs_roc_release() */
-       layoutreturn = pnfs_prepare_layoutreturn(lo, &stateid, &iomode);
+       layoutreturn = pnfs_prepare_layoutreturn(lo, &stateid, &lc_cred, &iomode);
        /* If the creds don't match, we can't compound the layoutreturn */
-       if (!layoutreturn || cred_fscmp(cred, lo->plh_lc_cred) != 0)
+       if (!layoutreturn)
                goto out_noroc;
+       if (cred_fscmp(cred, lc_cred) != 0)
+               goto out_noroc_put_cred;
 
        roc = layoutreturn;
        pnfs_init_layoutreturn_args(args, lo, &stateid, iomode);
        res->lrs_present = 0;
        layoutreturn = false;
 
+out_noroc_put_cred:
+       put_cred(lc_cred);
 out_noroc:
        spin_unlock(&ino->i_lock);
        rcu_read_unlock();
@@ -1467,7 +1480,7 @@ out_noroc:
                return true;
        }
        if (layoutreturn)
-               pnfs_send_layoutreturn(lo, &stateid, iomode, true);
+               pnfs_send_layoutreturn(lo, &stateid, &lc_cred, iomode, true);
        pnfs_put_layout_hdr(lo);
        return false;
 }
@@ -2464,13 +2477,14 @@ pnfs_mark_layout_for_return(struct inode *inode,
         * for how it works.
         */
        if (pnfs_mark_matching_lsegs_return(lo, &lo->plh_return_segs, range, 0) != -EBUSY) {
+               const struct cred *cred;
                nfs4_stateid stateid;
                enum pnfs_iomode iomode;
 
-               return_now = pnfs_prepare_layoutreturn(lo, &stateid, &iomode);
+               return_now = pnfs_prepare_layoutreturn(lo, &stateid, &cred, &iomode);
                spin_unlock(&inode->i_lock);
                if (return_now)
-                       pnfs_send_layoutreturn(lo, &stateid, iomode, false);
+                       pnfs_send_layoutreturn(lo, &stateid, &cred, iomode, false);
        } else {
                spin_unlock(&inode->i_lock);
                nfs_commit_inode(inode, 0);