nfsd: Ensure sampling of the write verifier is atomic with the write

When doing an unstable write, we need to ensure that we sample the
write verifier before releasing the lock, and allowing a commit to
the same file to proceed.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

diff --git a/fs/nfsd/nfs3proc.c b/fs/nfsd/nfs3proc.c
index ffdc592868a6c6499e80261da598a628f03a0c47..288bc76b4574de1eb22b3754572a2d18cb756f0d 100644 (file)
--- a/fs/nfsd/nfs3proc.c
+++ b/fs/nfsd/nfs3proc.c
@@ -203,7 +203,7 @@ nfsd3_proc_write(struct svc_rqst *rqstp)
                RETURN_STATUS(nfserr_io);
        nfserr = nfsd_write(rqstp, &resp->fh, argp->offset,
                            rqstp->rq_vec, nvecs, &cnt,
-                           resp->committed);
+                           resp->committed, resp->verf);
        resp->count = cnt;
        RETURN_STATUS(nfserr);
 }

diff --git a/fs/nfsd/nfs3xdr.c b/fs/nfsd/nfs3xdr.c
index 1ae4fc2eec0094440bc2b0e5119fd757906cba9a..aae514d40b641aba55d40c4431df41c56331cc5e 100644 (file)
--- a/fs/nfsd/nfs3xdr.c
+++ b/fs/nfsd/nfs3xdr.c
@@ -747,17 +747,13 @@ int
 nfs3svc_encode_writeres(struct svc_rqst *rqstp, __be32 *p)
 {
        struct nfsd3_writeres *resp = rqstp->rq_resp;
-       struct nfsd_net *nn = net_generic(SVC_NET(rqstp), nfsd_net_id);
-       __be32 verf[2];
 
        p = encode_wcc_data(rqstp, p, &resp->fh);
        if (resp->status == 0) {
                *p++ = htonl(resp->count);
                *p++ = htonl(resp->committed);
-               /* unique identifier, y2038 overflow can be ignored */
-               nfsd_copy_boot_verifier(verf, nn);
-               *p++ = verf[0];
-               *p++ = verf[1];
+               *p++ = resp->verf[0];
+               *p++ = resp->verf[1];
        }
        return xdr_ressize_check(rqstp, p);
 }

diff --git a/fs/nfsd/nfs4proc.c b/fs/nfsd/nfs4proc.c
index c3455e1b0d507524f20cfb1c354f1dd9b340d126..e4ddaf87493ae4b961b8f10f48dac7c9973046ab 100644 (file)
--- a/fs/nfsd/nfs4proc.c
+++ b/fs/nfsd/nfs4proc.c
@@ -1015,7 +1015,6 @@ nfsd4_write(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
        }
 
        write->wr_how_written = write->wr_stable_how;
-       gen_boot_verifier(&write->wr_verifier, SVC_NET(rqstp));
 
        nvecs = svc_fill_write_vector(rqstp, write->wr_pagelist,
                                      &write->wr_head, write->wr_buflen);
@@ -1023,7 +1022,8 @@ nfsd4_write(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
 
        status = nfsd_vfs_write(rqstp, &cstate->current_fh, nf,
                                write->wr_offset, rqstp->rq_vec, nvecs, &cnt,
-                               write->wr_how_written);
+                               write->wr_how_written,
+                               (__be32 *)write->wr_verifier.data);
        nfsd_file_put(nf);
 
        write->wr_bytes_written = cnt;

diff --git a/fs/nfsd/nfsproc.c b/fs/nfsd/nfsproc.c
index b25c90be29fbdecb8f0a993609936879b111ba87..543bbe0a556e7387c19e7aa40fd6400698766f86 100644 (file)
--- a/fs/nfsd/nfsproc.c
+++ b/fs/nfsd/nfsproc.c
@@ -226,7 +226,7 @@ nfsd_proc_write(struct svc_rqst *rqstp)
                return nfserr_io;
        nfserr = nfsd_write(rqstp, fh_copy(&resp->fh, &argp->fh),
                            argp->offset, rqstp->rq_vec, nvecs,
-                           &cnt, NFS_DATA_SYNC);
+                           &cnt, NFS_DATA_SYNC, NULL);
        return nfsd_return_attrs(nfserr, resp);
 }
 

diff --git a/fs/nfsd/vfs.c b/fs/nfsd/vfs.c
index dc07d9797f115faea0b098dbfc980684d85c64eb..0aa02eb18bd3c5ca22301ac1c1ab4fd029878d0f 100644 (file)
--- a/fs/nfsd/vfs.c
+++ b/fs/nfsd/vfs.c
@@ -962,7 +962,8 @@ static int wait_for_concurrent_writes(struct file *file)
 __be32
 nfsd_vfs_write(struct svc_rqst *rqstp, struct svc_fh *fhp, struct nfsd_file *nf,
                                loff_t offset, struct kvec *vec, int vlen,
-                               unsigned long *cnt, int stable)
+                               unsigned long *cnt, int stable,
+                               __be32 *verf)
 {
        struct file             *file = nf->nf_file;
        struct svc_export       *exp;
@@ -1004,6 +1005,10 @@ nfsd_vfs_write(struct svc_rqst *rqstp, struct svc_fh *fhp, struct nfsd_file *nf,
                up_write(&nf->nf_rwsem);
        } else {
                down_read(&nf->nf_rwsem);
+               if (verf)
+                       nfsd_copy_boot_verifier(verf,
+                                       net_generic(SVC_NET(rqstp),
+                                       nfsd_net_id));
                host_err = vfs_iter_write(file, &iter, &pos, flags);
                up_read(&nf->nf_rwsem);
        }
@@ -1074,7 +1079,8 @@ __be32 nfsd_read(struct svc_rqst *rqstp, struct svc_fh *fhp,
  */
 __be32
 nfsd_write(struct svc_rqst *rqstp, struct svc_fh *fhp, loff_t offset,
-          struct kvec *vec, int vlen, unsigned long *cnt, int stable)
+          struct kvec *vec, int vlen, unsigned long *cnt, int stable,
+          __be32 *verf)
 {
        struct nfsd_file *nf;
        __be32 err;
@@ -1086,7 +1092,7 @@ nfsd_write(struct svc_rqst *rqstp, struct svc_fh *fhp, loff_t offset,
                goto out;
 
        err = nfsd_vfs_write(rqstp, fhp, nf, offset, vec,
-                       vlen, cnt, stable);
+                       vlen, cnt, stable, verf);
        nfsd_file_put(nf);
 out:
        trace_nfsd_write_done(rqstp, fhp, offset, *cnt);

diff --git a/fs/nfsd/vfs.h b/fs/nfsd/vfs.h
index d23d9daacc3db282e0bc123662594aaaa703580c..3eb660ad80d1c5bc8d54f833f0b9733e7fdd1c00 100644 (file)
--- a/fs/nfsd/vfs.h
+++ b/fs/nfsd/vfs.h
@@ -94,11 +94,12 @@ __be32              nfsd_read(struct svc_rqst *, struct svc_fh *,
                                loff_t, struct kvec *, int, unsigned long *,
                                u32 *eof);
 __be32                 nfsd_write(struct svc_rqst *, struct svc_fh *, loff_t,
-                               struct kvec *, int, unsigned long *, int);
+                               struct kvec *, int, unsigned long *,
+                               int stable, __be32 *verf);
 __be32         nfsd_vfs_write(struct svc_rqst *rqstp, struct svc_fh *fhp,
                                struct nfsd_file *nf, loff_t offset,
                                struct kvec *vec, int vlen, unsigned long *cnt,
-                               int stable);
+                               int stable, __be32 *verf);
 __be32         nfsd_readlink(struct svc_rqst *, struct svc_fh *,
                                char *, int *);
 __be32         nfsd_symlink(struct svc_rqst *, struct svc_fh *,

diff --git a/fs/nfsd/xdr3.h b/fs/nfsd/xdr3.h
index fe6fd4556c2e58b3055328ac14c1f742363b87d2..4155fd71714c9c640a48b5a34e05f805132e48bb 100644 (file)
--- a/fs/nfsd/xdr3.h
+++ b/fs/nfsd/xdr3.h
@@ -159,6 +159,7 @@ struct nfsd3_writeres {
        struct svc_fh           fh;
        unsigned long           count;
        int                     committed;
+       __be32                  verf[2];
 };
 
 struct nfsd3_renameres {