6.18-stable review patch. If anyone has any objections, please let me know.
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From: Chuck Lever chuck.lever@oracle.com
commit e3e8e176ca4876e6212582022ad80835dddc9de4 upstream.
Mike noted that when NFSD responds to an NFS_FILE_SYNC WRITE, it does not also persist file time stamps. To wit, Section 18.32.3 of RFC 8881 mandates:
The client specifies with the stable parameter the method of how the data is to be processed by the server. If stable is FILE_SYNC4, the server MUST commit the data written plus all file system metadata to stable storage before returning results. This corresponds to the NFSv2 protocol semantics. Any other behavior constitutes a protocol violation. If stable is DATA_SYNC4, then the server MUST commit all of the data to stable storage and enough of the metadata to retrieve the data before returning.
Commit 3f3503adb332 ("NFSD: Use vfs_iocb_iter_write()") replaced:
- flags |= RWF_SYNC;
with:
+ kiocb.ki_flags |= IOCB_DSYNC;
which appears to be correct given:
if (flags & RWF_SYNC) kiocb_flags |= IOCB_DSYNC;
in kiocb_set_rw_flags(). However the author of that commit did not appreciate that the previous line in kiocb_set_rw_flags() results in IOCB_SYNC also being set:
kiocb_flags |= (__force int) (flags & RWF_SUPPORTED);
RWF_SUPPORTED contains RWF_SYNC, and RWF_SYNC is the same bit as IOCB_SYNC. Reviewers at the time did not catch the omission.
Reported-by: Mike Snitzer snitzer@kernel.org Closes: https://lore.kernel.org/linux-nfs/20251018005431.3403-1-cel@kernel.org/T/#t Fixes: 3f3503adb332 ("NFSD: Use vfs_iocb_iter_write()") Cc: stable@vger.kernel.org Reviewed-by: Jeff Layton jlayton@kernel.org Reviewed-by: NeilBrown neil@brown.name Reviewed-by: Christoph Hellwig hch@lst.de Signed-off-by: Chuck Lever chuck.lever@oracle.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- fs/nfsd/vfs.c | 14 ++++++++++++-- 1 file changed, 12 insertions(+), 2 deletions(-)
--- a/fs/nfsd/vfs.c +++ b/fs/nfsd/vfs.c @@ -1228,8 +1228,18 @@ nfsd_vfs_write(struct svc_rqst *rqstp, s stable = NFS_UNSTABLE; init_sync_kiocb(&kiocb, file); kiocb.ki_pos = offset; - if (stable && !fhp->fh_use_wgather) - kiocb.ki_flags |= IOCB_DSYNC; + if (likely(!fhp->fh_use_wgather)) { + switch (stable) { + case NFS_FILE_SYNC: + /* persist data and timestamps */ + kiocb.ki_flags |= IOCB_DSYNC | IOCB_SYNC; + break; + case NFS_DATA_SYNC: + /* persist data only */ + kiocb.ki_flags |= IOCB_DSYNC; + break; + } + }
nvecs = xdr_buf_to_bvec(rqstp->rq_bvec, rqstp->rq_maxpages, payload); iov_iter_bvec(&iter, ITER_SOURCE, rqstp->rq_bvec, nvecs, *cnt);