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NFSD: COMMIT operations must not return NFS?ERR_INVAL 

[ Upstream commit 3f965021c8 ]

Since, well, forever, the Linux NFS server's nfsd_commit() function
has returned nfserr_inval when the passed-in byte range arguments
were non-sensical.

However, according to RFC 1813 section 3.3.21, NFSv3 COMMIT requests
are permitted to return only the following non-zero status codes:

      NFS3ERR_IO
      NFS3ERR_STALE
      NFS3ERR_BADHANDLE
      NFS3ERR_SERVERFAULT

NFS3ERR_INVAL is not included in that list. Likewise, NFS4ERR_INVAL
is not listed in the COMMIT row of Table 6 in RFC 8881.

RFC 7530 does permit COMMIT to return NFS4ERR_INVAL, but does not
specify when it can or should be used.

Instead of dropping or failing a COMMIT request in a byte range that
is not supported, turn it into a valid request by treating one or
both arguments as zero. Offset zero means start-of-file, count zero
means until-end-of-file, so we only ever extend the commit range.
NFS servers are always allowed to commit more and sooner than
requested.

The range check is no longer bounded by NFS_OFFSET_MAX, but rather
by the value that is returned in the maxfilesize field of the NFSv3
FSINFO procedure or the NFSv4 maxfilesize file attribute.

Note that this change results in a new pynfs failure:

CMT4     st_commit.testCommitOverflow                             : RUNNING
CMT4     st_commit.testCommitOverflow                             : FAILURE
           COMMIT with offset + count overflow should return
           NFS4ERR_INVAL, instead got NFS4_OK

IMO the test is not correct as written: RFC 8881 does not allow the
COMMIT operation to return NFS4ERR_INVAL.

Reported-by: Dan Aloni <dan.aloni@vastdata.com>
Cc: stable@vger.kernel.org
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Reviewed-by: Bruce Fields <bfields@fieldses.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Chuck Lever 2022-01-24 15:50:31 -05:00 committed by Greg Kroah-Hartman
parent c2a9881bc2
commit d6f1651ddf
3 changed files with 38 additions and 25 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

6
fs/nfsd/nfs3proc.c
View File

@ -660,15 +660,9 @@ nfsd3_proc_commit(struct svc_rqst *rqstp)
argp->count,
(unsigned long long) argp->offset);
if (argp->offset > NFS_OFFSET_MAX) {
resp->status = nfserr_inval;
goto out;
}
fh_copy(&resp->fh, &argp->fh);
resp->status = nfsd_commit(rqstp, &resp->fh, argp->offset,
argp->count, resp->verf);
out:
return rpc_success;
}

53
fs/nfsd/vfs.c
View File

@ -1108,42 +1108,61 @@ out:
}
#ifdef CONFIG_NFSD_V3
/*
* Commit all pending writes to stable storage.
/**
* nfsd_commit - Commit pending writes to stable storage
* @rqstp: RPC request being processed
* @fhp: NFS filehandle
* @offset: raw offset from beginning of file
* @count: raw count of bytes to sync
* @verf: filled in with the server's current write verifier
*
* Note: we only guarantee that data that lies within the range specified
* by the 'offset' and 'count' parameters will be synced.
* Note: we guarantee that data that lies within the range specified
* by the 'offset' and 'count' parameters will be synced. The server
* is permitted to sync data that lies outside this range at the
* same time.
*
* Unfortunately we cannot lock the file to make sure we return full WCC
* data to the client, as locking happens lower down in the filesystem.
*
* Return values:
* An nfsstat value in network byte order.
*/
__be32
nfsd_commit(struct svc_rqst *rqstp, struct svc_fh *fhp,
loff_t offset, unsigned long count, __be32 *verf)
nfsd_commit(struct svc_rqst *rqstp, struct svc_fh *fhp, u64 offset,
u32 count, __be32 *verf)
{
u64 maxbytes;
loff_t start, end;
struct nfsd_net *nn;
struct nfsd_file *nf;
loff_t end = LLONG_MAX;
__be32 err = nfserr_inval;
if (offset < 0)
goto out;
if (count != 0) {
end = offset + (loff_t)count - 1;
if (end < offset)
goto out;
}
__be32 err;
err = nfsd_file_acquire(rqstp, fhp,
NFSD_MAY_WRITE|NFSD_MAY_NOT_BREAK_LEASE, &nf);
if (err)
goto out;
/*
* Convert the client-provided (offset, count) range to a
* (start, end) range. If the client-provided range falls
* outside the maximum file size of the underlying FS,
* clamp the sync range appropriately.
*/
start = 0;
end = LLONG_MAX;
maxbytes = (u64)fhp->fh_dentry->d_sb->s_maxbytes;
if (offset < maxbytes) {
start = offset;
if (count && (offset + count - 1 < maxbytes))
end = offset + count - 1;
}
nn = net_generic(nf->nf_net, nfsd_net_id);
if (EX_ISSYNC(fhp->fh_export)) {
errseq_t since = READ_ONCE(nf->nf_file->f_wb_err);
int err2;
err2 = vfs_fsync_range(nf->nf_file, offset, end, 0);
err2 = vfs_fsync_range(nf->nf_file, start, end, 0);
switch (err2) {
case 0:
nfsd_copy_boot_verifier(verf, nn);

4
fs/nfsd/vfs.h
View File

@ -73,8 +73,8 @@ __be32 do_nfsd_create(struct svc_rqst *, struct svc_fh *,
char *name, int len, struct iattr *attrs,
struct svc_fh *res, int createmode,
u32 *verifier, bool *truncp, bool *created);
__be32 nfsd_commit(struct svc_rqst *, struct svc_fh *,
loff_t, unsigned long, __be32 *verf);
__be32 nfsd_commit(struct svc_rqst *rqst, struct svc_fh *fhp,
u64 offset, u32 count, __be32 *verf);
#endif /* CONFIG_NFSD_V3 */
#ifdef CONFIG_NFSD_V4
__be32 nfsd_getxattr(struct svc_rqst *rqstp, struct svc_fh *fhp,