From: Chuck Lever Date: Wed, 7 May 2025 14:45:15 +0000 (-0400) Subject: NFSD: Implement FATTR4_CLONE_BLKSIZE attribute X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=d6ca7d2643eebe09cf46840bdc7d68b6e07aba77;p=users%2Fhch%2Fmisc.git NFSD: Implement FATTR4_CLONE_BLKSIZE attribute RFC 7862 states that if an NFS server implements a CLONE operation, it MUST also implement FATTR4_CLONE_BLKSIZE. NFSD implements CLONE, but does not implement FATTR4_CLONE_BLKSIZE. Note that in Section 12.2, RFC 7862 claims that FATTR4_CLONE_BLKSIZE is RECOMMENDED, not REQUIRED. Likely this is because a minor version is not permitted to add a REQUIRED attribute. Confusing. We assume this attribute reports a block size as a count of bytes, as RFC 7862 does not specify a unit. Reported-by: Roland Mainz Suggested-by: Christoph Hellwig Reviewed-by: Roland Mainz Cc: stable@vger.kernel.org # v6.7+ Reviewed-by: Jeff Layton Signed-off-by: Chuck Lever --- diff --git a/fs/nfsd/nfs4xdr.c b/fs/nfsd/nfs4xdr.c index e67420729ecd..9eb8e5704622 100644 --- a/fs/nfsd/nfs4xdr.c +++ b/fs/nfsd/nfs4xdr.c @@ -3391,6 +3391,23 @@ static __be32 nfsd4_encode_fattr4_suppattr_exclcreat(struct xdr_stream *xdr, return nfsd4_encode_bitmap4(xdr, supp[0], supp[1], supp[2]); } +/* + * Copied from generic_remap_checks/generic_remap_file_range_prep. + * + * These generic functions use the file system's s_blocksize, but + * individual file systems aren't required to use + * generic_remap_file_range_prep. Until there is a mechanism for + * determining a particular file system's (or file's) clone block + * size, this is the best NFSD can do. + */ +static __be32 nfsd4_encode_fattr4_clone_blksize(struct xdr_stream *xdr, + const struct nfsd4_fattr_args *args) +{ + struct inode *inode = d_inode(args->dentry); + + return nfsd4_encode_uint32_t(xdr, inode->i_sb->s_blocksize); +} + #ifdef CONFIG_NFSD_V4_SECURITY_LABEL static __be32 nfsd4_encode_fattr4_sec_label(struct xdr_stream *xdr, const struct nfsd4_fattr_args *args) @@ -3545,7 +3562,7 @@ static const nfsd4_enc_attr nfsd4_enc_fattr4_encode_ops[] = { [FATTR4_MODE_SET_MASKED] = nfsd4_encode_fattr4__noop, [FATTR4_SUPPATTR_EXCLCREAT] = nfsd4_encode_fattr4_suppattr_exclcreat, [FATTR4_FS_CHARSET_CAP] = nfsd4_encode_fattr4__noop, - [FATTR4_CLONE_BLKSIZE] = nfsd4_encode_fattr4__noop, + [FATTR4_CLONE_BLKSIZE] = nfsd4_encode_fattr4_clone_blksize, [FATTR4_SPACE_FREED] = nfsd4_encode_fattr4__noop, [FATTR4_CHANGE_ATTR_TYPE] = nfsd4_encode_fattr4__noop,