nfs4.2: add UNCACHEABLE_FILE_DATA attribute support

Recognize the NFSv4.2 per-file UNCACHEABLE_FILE_DATA attribute (attr 87, draft-ietf-nfsv4-uncacheable-files): decode it via GETATTR, track per- exported-filesystem support, and record on the inode whether a regular file's data must not be cached. Acting on the attribute (opening such files O_DIRECT) is done by a subsequent change. If the NFSv4 server reports a regular file's UNCACHEABLE_FILE_DATA as true, it indicates the file's data must not be cached; the client records this in NFS_I(inode)->uncacheable_file_data for use by the I/O paths. The UNCACHEABLE_FILE_DATA attribute applies only to regular files (NF4REG); per the draft a server MUST reject a query of it on any other object type with NFS4ERR_INVAL. A subsequent commit gates the client accordingly. Link: https://datatracker.ietf.org/doc/draft-ietf-nfsv4-uncacheable-files/ Signed-off-by: Tom Haynes <loghyr@hammerspace.com> [snitzer: adapt Tom's original code focused on metadata for ABE] Co-developed-by: Mike Snitzer <snitzer@hammerspace.com> Signed-off-by: Mike Snitzer <snitzer@hammerspace.com> Signed-off-by: Mike Snitzer <snitzer@kernel.org> Assisted-by: Claude:claude-opus-4-8 Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2026-09-14 08:01:12 +02:00 · 2026-07-27 17:09:38 -04:00 · 2026-07-27 17:09:38 -04:00 · 86ff184279
commit 86ff184279
parent 4a013b0e88
8 changed files with 88 additions and 10 deletions
--- a/fs/nfs/inode.c
+++ b/fs/nfs/inode.c
@ -507,6 +507,7 @@ nfs_fhget(struct super_block *sb, struct nfs_fh *fh, struct nfs_fattr *fattr)
 		inode->i_blocks = 0;
 		nfsi->write_io = 0;
 		nfsi->read_io = 0;
+		nfsi->uncacheable_file_data = false;

 		nfsi->read_cache_jiffies = fattr->time_start;
 		nfsi->attr_gencount = fattr->gencount;
@ -561,6 +562,11 @@ nfs_fhget(struct super_block *sb, struct nfs_fh *fh, struct nfs_fattr *fattr)
 		} else if (fattr_supported & NFS_ATTR_FATTR_SPACE_USED &&
 			   fattr->size != 0)
 			nfs_set_cache_invalid(inode, NFS_INO_INVALID_BLOCKS);
+		if (fattr->valid & NFS_ATTR_FATTR_UNCACHEABLE_FILE_DATA)
+			nfsi->uncacheable_file_data =
+				fattr->aux_flags & NFS_AUX_UNCACHEABLE_FILE_DATA;
+		else if (fattr_supported & NFS_ATTR_FATTR_UNCACHEABLE_FILE_DATA)
+			nfs_set_cache_invalid(inode, NFS_INO_INVALID_UNCACHEABLE_FILE_DATA);

 		nfs_setsecurity(inode, fattr);

@ -1973,7 +1979,8 @@ static int nfs_inode_finish_partial_attr_update(const struct nfs_fattr *fattr,
 		NFS_INO_INVALID_ATIME | NFS_INO_INVALID_CTIME |
 		NFS_INO_INVALID_MTIME | NFS_INO_INVALID_SIZE |
 		NFS_INO_INVALID_BLOCKS | NFS_INO_INVALID_OTHER |
-		NFS_INO_INVALID_NLINK | NFS_INO_INVALID_BTIME;
+		NFS_INO_INVALID_NLINK | NFS_INO_INVALID_BTIME |
+		NFS_INO_INVALID_UNCACHEABLE_FILE_DATA;
 	unsigned long cache_validity = NFS_I(inode)->cache_validity;
 	enum nfs4_change_attr_type ctype = NFS_SERVER(inode)->change_attr_type;

@ -2295,7 +2302,8 @@ static int nfs_update_inode(struct inode *inode, struct nfs_fattr *fattr)
 	nfsi->cache_validity &= ~(NFS_INO_INVALID_ATTR
 			| NFS_INO_INVALID_ATIME
 			| NFS_INO_REVAL_FORCED
-			| NFS_INO_INVALID_BLOCKS);
+			| NFS_INO_INVALID_BLOCKS
+			| NFS_INO_INVALID_UNCACHEABLE_FILE_DATA);

 	/* Do atomic weak cache consistency updates */
 	nfs_wcc_update_inode(inode, fattr);
@ -2335,7 +2343,8 @@ static int nfs_update_inode(struct inode *inode, struct nfs_fattr *fattr)
 					| NFS_INO_INVALID_NLINK
 					| NFS_INO_INVALID_MODE
 					| NFS_INO_INVALID_OTHER
-					| NFS_INO_INVALID_BTIME;
+					| NFS_INO_INVALID_BTIME
+					| NFS_INO_INVALID_UNCACHEABLE_FILE_DATA;
 				if (S_ISDIR(inode->i_mode))
 					nfs_force_lookup_revalidate(inode);
 				attr_changed = true;
@ -2459,6 +2468,13 @@ static int nfs_update_inode(struct inode *inode, struct nfs_fattr *fattr)
 		nfsi->cache_validity |=
 			save_cache_validity & NFS_INO_INVALID_BLOCKS;

+	if (fattr->valid & NFS_ATTR_FATTR_UNCACHEABLE_FILE_DATA)
+		nfsi->uncacheable_file_data =
+				fattr->aux_flags & NFS_AUX_UNCACHEABLE_FILE_DATA;
+	else if (fattr_supported & NFS_ATTR_FATTR_UNCACHEABLE_FILE_DATA)
+		nfsi->cache_validity |=
+			save_cache_validity & NFS_INO_INVALID_UNCACHEABLE_FILE_DATA;
+
 	/* Update attrtimeo value if we're out of the unstable period */
 	if (attr_changed) {
 		nfs_inc_stats(inode, NFSIOS_ATTRINVALIDATE);
--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@ -225,8 +225,9 @@ const u32 nfs4_fattr_bitmap[3] = {
 	| FATTR4_WORD1_TIME_METADATA
 	| FATTR4_WORD1_TIME_MODIFY
 	| FATTR4_WORD1_MOUNTED_ON_FILEID,
+	FATTR4_WORD2_UNCACHEABLE_FILE_DATA
 #ifdef CONFIG_NFS_V4_SECURITY_LABEL
-	FATTR4_WORD2_SECURITY_LABEL
+	| FATTR4_WORD2_SECURITY_LABEL
 #endif
 };

@ -250,6 +251,7 @@ static const u32 nfs4_pnfs_open_bitmap[3] = {
 #ifdef CONFIG_NFS_V4_SECURITY_LABEL
 	| FATTR4_WORD2_SECURITY_LABEL
 #endif
+	| FATTR4_WORD2_UNCACHEABLE_FILE_DATA
 };

 static const u32 nfs4_open_noattr_bitmap[3] = {
@ -327,6 +329,9 @@ static void nfs4_bitmap_copy_adjust(__u32 *dst, const __u32 *src,
 	if (!(cache_validity & NFS_INO_INVALID_BTIME))
 		dst[1] &= ~FATTR4_WORD1_TIME_CREATE;

+	if (!(cache_validity & NFS_INO_INVALID_UNCACHEABLE_FILE_DATA))
+		dst[2] &= ~FATTR4_WORD2_UNCACHEABLE_FILE_DATA;
+
 	if (nfs_have_delegated_mtime(inode)) {
 		if (!(cache_validity & NFS_INO_INVALID_ATIME))
 			dst[1] &= ~(FATTR4_WORD1_TIME_ACCESS|FATTR4_WORD1_TIME_ACCESS_SET);
@ -1238,7 +1243,7 @@ nfs4_update_changeattr_locked(struct inode *inode,
 				NFS_INO_INVALID_SIZE | NFS_INO_INVALID_OTHER |
 				NFS_INO_INVALID_BLOCKS | NFS_INO_INVALID_NLINK |
 				NFS_INO_INVALID_MODE | NFS_INO_INVALID_BTIME |
-				NFS_INO_INVALID_XATTR;
+				NFS_INO_INVALID_XATTR | NFS_INO_INVALID_UNCACHEABLE_FILE_DATA;
 		nfsi->attrtimeo = NFS_MINATTRTIMEO(inode);
 	}
 	nfsi->attrtimeo_timestamp = jiffies;
@ -3857,7 +3862,7 @@ static void nfs4_close_context(struct nfs_open_context *ctx, int is_sync)

 #define FATTR4_WORD1_NFS40_MASK (2*FATTR4_WORD1_MOUNTED_ON_FILEID - 1UL)
 #define FATTR4_WORD2_NFS41_MASK (2*FATTR4_WORD2_SUPPATTR_EXCLCREAT - 1UL)
-#define FATTR4_WORD2_NFS42_MASK (2*FATTR4_WORD2_OPEN_ARGUMENTS - 1UL)
+#define FATTR4_WORD2_NFS42_MASK (2*FATTR4_WORD2_UNCACHEABLE_FILE_DATA - 1UL)

 #define FATTR4_WORD2_NFS42_TIME_DELEG_MASK \
 	(FATTR4_WORD2_TIME_DELEG_MODIFY|FATTR4_WORD2_TIME_DELEG_ACCESS)
@ -3981,6 +3986,8 @@ static int _nfs4_server_capabilities(struct nfs_server *server, struct nfs_fh *f
 		memcpy(server->attr_bitmask_nl, res.attr_bitmask,
 				sizeof(server->attr_bitmask));
 		server->attr_bitmask_nl[2] &= ~FATTR4_WORD2_SECURITY_LABEL;
+		if (!(res.attr_bitmask[2] & FATTR4_WORD2_UNCACHEABLE_FILE_DATA))
+			server->fattr_valid &= ~NFS_ATTR_FATTR_UNCACHEABLE_FILE_DATA;

 		if (res.open_caps.oa_share_access_want[0] &
 		    NFS4_SHARE_WANT_OPEN_XOR_DELEGATION)
@ -5809,6 +5816,8 @@ void nfs4_bitmask_set(__u32 bitmask[], const __u32 src[],
 		bitmask[1] |= FATTR4_WORD1_SPACE_USED;
 	if (cache_validity & NFS_INO_INVALID_BTIME)
 		bitmask[1] |= FATTR4_WORD1_TIME_CREATE;
+	if (cache_validity & NFS_INO_INVALID_UNCACHEABLE_FILE_DATA)
+		bitmask[2] |= FATTR4_WORD2_UNCACHEABLE_FILE_DATA;

 	if (cache_validity & NFS_INO_INVALID_SIZE)
 		bitmask[0] |= FATTR4_WORD0_SIZE;
--- a/fs/nfs/nfs4trace.h
+++ b/fs/nfs/nfs4trace.h
@ -33,7 +33,8 @@
 		{ NFS_ATTR_FATTR_CHANGE, "CHANGE" }, \
 		{ NFS_ATTR_FATTR_OWNER_NAME, "OWNER_NAME" }, \
 		{ NFS_ATTR_FATTR_GROUP_NAME, "GROUP_NAME" }, \
-		{ NFS_ATTR_FATTR_BTIME, "BTIME" })
+		{ NFS_ATTR_FATTR_BTIME, "BTIME" }, \
+		{ NFS_ATTR_FATTR_UNCACHEABLE_FILE_DATA, "UNCACHEABLE_FILE_DATA" })

 DECLARE_EVENT_CLASS(nfs4_clientid_event,
 		TP_PROTO(
--- a/fs/nfs/nfs4xdr.c
+++ b/fs/nfs/nfs4xdr.c
@ -120,7 +120,8 @@ static int decode_layoutget(struct xdr_stream *xdr, struct rpc_rqst *req,
 				3*nfstime4_maxsz + \
 				nfs4_owner_maxsz + \
 				nfs4_group_maxsz + nfs4_label_maxsz + \
-				 decode_mdsthreshold_maxsz))
+				 decode_mdsthreshold_maxsz + \
+				 1)) /* uncacheable_file_data */
 #define nfs4_fattr_maxsz	(nfs4_fattr_bitmap_maxsz + \
 				nfs4_fattr_value_maxsz)
 #define decode_getattr_maxsz    (op_decode_hdr_maxsz + nfs4_fattr_maxsz)
@ -4380,6 +4381,30 @@ static int decode_attr_open_arguments(struct xdr_stream *xdr, uint32_t *bitmap,
 	return 0;
 }

+static int decode_attr_uncacheable_file_data(struct xdr_stream *xdr, uint32_t *bitmap,
+				   uint32_t *res, uint64_t *flags)
+{
+	int status = 0;
+	__be32 *p;
+
+	if (unlikely(bitmap[2] & (FATTR4_WORD2_UNCACHEABLE_FILE_DATA - 1U)))
+		return -EIO;
+	if (likely(bitmap[2] & FATTR4_WORD2_UNCACHEABLE_FILE_DATA)) {
+		p = xdr_inline_decode(xdr, 4);
+		if (unlikely(!p))
+			return -EIO;
+		if (be32_to_cpup(p))
+			*res |= NFS_AUX_UNCACHEABLE_FILE_DATA;
+		else
+			*res &= ~NFS_AUX_UNCACHEABLE_FILE_DATA;
+		bitmap[2] &= ~FATTR4_WORD2_UNCACHEABLE_FILE_DATA;
+		*flags |= NFS_ATTR_FATTR_UNCACHEABLE_FILE_DATA;
+	}
+	dprintk("%s: uncacheable_file_data: =%s\n", __func__,
+		(*res & NFS_AUX_UNCACHEABLE_FILE_DATA) == 0 ? "false" : "true");
+	return status;
+}
+
 static int verify_attr_len(struct xdr_stream *xdr, unsigned int savep, uint32_t attrlen)
 {
 	unsigned int attrwords = XDR_QUADLEN(attrlen);
@ -4725,6 +4750,8 @@ static int decode_getfattr_attrs(struct xdr_stream *xdr, uint32_t *bitmap,
 	uint32_t type;
 	int32_t err;

+	fattr->aux_flags = 0;
+
 	status = decode_attr_type(xdr, bitmap, &type);
 	if (status < 0)
 		goto xdr_error;
@ -4843,6 +4870,12 @@ static int decode_getfattr_attrs(struct xdr_stream *xdr, uint32_t *bitmap,
 		goto xdr_error;
 	fattr->valid |= status;

+	status = decode_attr_uncacheable_file_data(xdr, bitmap, &fattr->aux_flags,
+					 &fattr->valid);
+	if (status < 0)
+		goto xdr_error;
+
+	status = 0;
 xdr_error:
 	dprintk("%s: xdr returned %d\n", __func__, -status);
 	return status;
--- a/fs/nfs/nfstrace.h
+++ b/fs/nfs/nfstrace.h
@ -33,7 +33,8 @@
 			{ NFS_INO_INVALID_XATTR, "INVALID_XATTR" }, \
 			{ NFS_INO_INVALID_NLINK, "INVALID_NLINK" }, \
 			{ NFS_INO_INVALID_MODE, "INVALID_MODE" }, \
-			{ NFS_INO_INVALID_BTIME, "INVALID_BTIME" })
+			{ NFS_INO_INVALID_BTIME, "INVALID_BTIME" }, \
+			{ NFS_INO_INVALID_UNCACHEABLE_FILE_DATA, "INVALID_UNCACHEABLE_FILE_DATA" })

 #define nfs_show_nfsi_flags(v) \
 	__print_flags(v, "|", \
--- a/include/linux/nfs4.h
+++ b/include/linux/nfs4.h
@ -516,6 +516,14 @@ enum {
 	FATTR4_XATTR_SUPPORT		= 82,
 };

+/*
+ * Symbol name and value are from draft-ietf-nfsv4-uncacheable-files
+ * Section 7.  "XDR for Uncacheable Attribute"
+ */
+enum {
+	FATTR4_UNCACHEABLE_FILE_DATA	= 87,
+};
+
 /*
 * The following internal definitions enable processing the above
 * attribute bits within 32-bit word boundaries.
@ -602,6 +610,7 @@ enum {
 #define FATTR4_WORD2_ACL_TRUEFORM_SCOPE	BIT(FATTR4_ACL_TRUEFORM_SCOPE - 64)
 #define FATTR4_WORD2_POSIX_DEFAULT_ACL	BIT(FATTR4_POSIX_DEFAULT_ACL - 64)
 #define FATTR4_WORD2_POSIX_ACCESS_ACL	BIT(FATTR4_POSIX_ACCESS_ACL - 64)
+#define FATTR4_WORD2_UNCACHEABLE_FILE_DATA	BIT(FATTR4_UNCACHEABLE_FILE_DATA - 64)

 /* MDS threshold bitmap bits */
 #define THRESHOLD_RD                    (1UL << 0)
--- a/include/linux/nfs_fs.h
+++ b/include/linux/nfs_fs.h
@ -162,6 +162,8 @@ struct nfs_inode {

 	struct timespec64	btime;

+	bool			uncacheable_file_data : 1;
+
 	/*
 	 * read_cache_jiffies is when we started read-caching this inode.
 	 * attrtimeo is for how long the cached information is assumed
@ -319,6 +321,7 @@ struct nfs4_copy_state {
 #define NFS_INO_INVALID_NLINK	BIT(16)		/* cached nlinks is invalid */
 #define NFS_INO_INVALID_MODE	BIT(17)		/* cached mode is invalid */
 #define NFS_INO_INVALID_BTIME	BIT(18)		/* cached btime is invalid */
+#define NFS_INO_INVALID_UNCACHEABLE_FILE_DATA	BIT(19)		/* cached uncacheable_file_data is invalid */

 #define NFS_INO_INVALID_ATTR	(NFS_INO_INVALID_CHANGE \
 		| NFS_INO_INVALID_CTIME \
--- a/include/linux/nfs_xdr.h
+++ b/include/linux/nfs_xdr.h
@ -17,6 +17,9 @@

 #define NFS_BITMASK_SZ		3

+/* aux_flags in nfs_fattr */
+#define NFS_AUX_UNCACHEABLE_FILE_DATA	BIT(0)
+
 struct nfs4_string {
 	unsigned int len;
 	char *data;
@ -68,6 +71,7 @@ struct nfs_fattr {
 	struct timespec64	mtime;
 	struct timespec64	ctime;
 	struct timespec64	btime;
+	__u32			aux_flags;	/* NFSv4 auxiliary flags bitfield */
 	__u64			change_attr;	/* NFSv4 change attribute */
 	__u64			pre_change_attr;/* pre-op NFSv4 change attribute */
 	__u64			pre_size;	/* pre_op_attr.size	  */
@ -108,6 +112,7 @@ struct nfs_fattr {
 #define NFS_ATTR_FATTR_GROUP_NAME	BIT_ULL(24)
 #define NFS_ATTR_FATTR_V4_SECURITY_LABEL BIT_ULL(25)
 #define NFS_ATTR_FATTR_BTIME		BIT_ULL(26)
+#define NFS_ATTR_FATTR_UNCACHEABLE_FILE_DATA	BIT_ULL(27)

 #define NFS_ATTR_FATTR (NFS_ATTR_FATTR_TYPE \
 		| NFS_ATTR_FATTR_MODE \
@ -129,7 +134,8 @@ struct nfs_fattr {
 #define NFS_ATTR_FATTR_V4 (NFS_ATTR_FATTR \
 		| NFS_ATTR_FATTR_SPACE_USED \
 		| NFS_ATTR_FATTR_BTIME \
-		| NFS_ATTR_FATTR_V4_SECURITY_LABEL)
+		| NFS_ATTR_FATTR_V4_SECURITY_LABEL \
+		| NFS_ATTR_FATTR_UNCACHEABLE_FILE_DATA)

 /*
 * Maximal number of supported layout drivers.