[PATCH v3] nfsd: Use correct error code when decoding extents

Sergey Bashirov
2025-06-12T21:43:22Z

Update error codes in decoding functions of block and scsi layout
drivers to match the core nfsd code. NFS4ERR_EINVAL means that the
server was able to decode the request, but the decoded values are
invalid. Use NFS4ERR_BADXDR instead to indicate a decoding error.
And ENOMEM is changed to nfs code NFS4ERR_DELAY.

Signed-off-by: Sergey Bashirov <sergeybashirov@gmail.com>
---
Changes in v3:
- Add nfserr_delay define
- Return number of iomaps and nfserror as separate values

fs/nfsd/blocklayout.c | 20 ++++++-----
fs/nfsd/blocklayoutxdr.c | 71 +++++++++++++++++++++++++++++++---------
fs/nfsd/blocklayoutxdr.h | 8 ++---
fs/nfsd/nfsd.h | 1 +
4 files changed, 73 insertions(+), 27 deletions(-)

diff --git a/fs/nfsd/blocklayout.c b/fs/nfsd/blocklayout.c
index 08a20e5bcf7f..19078a043e85 100644
--- a/fs/nfsd/blocklayout.c
+++ b/fs/nfsd/blocklayout.c
@@ -178,11 +178,13 @@ nfsd4_block_proc_layoutcommit(struct inode *inode,
{
struct iomap *iomaps;
int nr_iomaps;
+ __be32 nfserr;

- nr_iomaps = nfsd4_block_decode_layoutupdate(lcp->lc_up_layout,
- lcp->lc_up_len, &iomaps, i_blocksize(inode));
- if (nr_iomaps < 0)
- return nfserrno(nr_iomaps);
+ nfserr = nfsd4_block_decode_layoutupdate(lcp->lc_up_layout,
+ lcp->lc_up_len, &iomaps, &nr_iomaps,
+ i_blocksize(inode));
+ if (nfserr != nfs_ok)
+ return nfserr;

return nfsd4_block_commit_blocks(inode, lcp, iomaps, nr_iomaps);
}
@@ -316,11 +318,13 @@ nfsd4_scsi_proc_layoutcommit(struct inode *inode,
{
struct iomap *iomaps;
int nr_iomaps;
+ __be32 nfserr;

- nr_iomaps = nfsd4_scsi_decode_layoutupdate(lcp->lc_up_layout,
- lcp->lc_up_len, &iomaps, i_blocksize(inode));
- if (nr_iomaps < 0)
- return nfserrno(nr_iomaps);
+ nfserr = nfsd4_scsi_decode_layoutupdate(lcp->lc_up_layout,
+ lcp->lc_up_len, &iomaps, &nr_iomaps,
+ i_blocksize(inode));
+ if (nfserr != nfs_ok)
+ return nfserr;

return nfsd4_block_commit_blocks(inode, lcp, iomaps, nr_iomaps);
}
diff --git a/fs/nfsd/blocklayoutxdr.c b/fs/nfsd/blocklayoutxdr.c
index ce78f74715ee..669ff8e6e966 100644
--- a/fs/nfsd/blocklayoutxdr.c
+++ b/fs/nfsd/blocklayoutxdr.c
@@ -112,34 +112,54 @@ nfsd4_block_encode_getdeviceinfo(struct xdr_stream *xdr,
return 0;
}

-int
+/**
+ * nfsd4_block_decode_layoutupdate - decode the block layout extent array
+ * @p: pointer to the xdr data
+ * @len: number of bytes to decode
+ * @iomapp: pointer to store the decoded extent array
+ * @nr_iomapsp: pointer to store the number of extents
+ * @block_size: alignment of extent offset and length
+ *
+ * This function decodes the opaque field of the layoutupdate4 structure
+ * in a layoutcommit request for the block layout driver. The field is
+ * actually an array of extents sent by the client. It also checks that
+ * the file offset, storage offset and length of each extent are aligned
+ * by @block_size.
+ *
+ * Return values:
+ * %nfs_ok: Successful decoding, @iomapp and @nr_iomapsp are valid
+ * %nfserr_bad_xdr: The encoded array in @p is invalid
+ * %nfserr_inval: An unaligned extent found
+ * %nfserr_delay: Failed to allocate memory for @iomapp
+ */
+__be32
nfsd4_block_decode_layoutupdate(__be32 *p, u32 len, struct iomap **iomapp,
- u32 block_size)
+ int *nr_iomapsp, u32 block_size)
{
struct iomap *iomaps;
u32 nr_iomaps, i;

if (len < sizeof(u32)) {
dprintk("%s: extent array too small: %u\n", __func__, len);
- return -EINVAL;
+ return nfserr_bad_xdr;
}
len -= sizeof(u32);
if (len % PNFS_BLOCK_EXTENT_SIZE) {
dprintk("%s: extent array invalid: %u\n", __func__, len);
- return -EINVAL;
+ return nfserr_bad_xdr;
}

nr_iomaps = be32_to_cpup(p++);
if (nr_iomaps != len / PNFS_BLOCK_EXTENT_SIZE) {
dprintk("%s: extent array size mismatch: %u/%u\n",
__func__, len, nr_iomaps);
- return -EINVAL;
+ return nfserr_bad_xdr;
}

iomaps = kcalloc(nr_iomaps, sizeof(*iomaps), GFP_KERNEL);
if (!iomaps) {
dprintk("%s: failed to allocate extent array\n", __func__);
- return -ENOMEM;
+ return nfserr_delay;
}

for (i = 0; i < nr_iomaps; i++) {
@@ -178,22 +198,42 @@ nfsd4_block_decode_layoutupdate(__be32 *p, u32 len, struct iomap **iomapp,
}

*iomapp = iomaps;
- return nr_iomaps;
+ *nr_iomapsp = nr_iomaps;
+ return nfs_ok;
fail:
kfree(iomaps);
- return -EINVAL;
+ return nfserr_inval;
}

-int
+/**
+ * nfsd4_scsi_decode_layoutupdate - decode the scsi layout extent array
+ * @p: pointer to the xdr data
+ * @len: number of bytes to decode
+ * @iomapp: pointer to store the decoded extent array
+ * @nr_iomapsp: pointer to store the number of extents
+ * @block_size: alignment of extent offset and length
+ *
+ * This function decodes the opaque field of the layoutupdate4 structure
+ * in a layoutcommit request for the scsi layout driver. The field is
+ * actually an array of extents sent by the client. It also checks that
+ * the offset and length of each extent are aligned by @block_size.
+ *
+ * Return values:
+ * %nfs_ok: Successful decoding, @iomapp and @nr_iomapsp are valid
+ * %nfserr_bad_xdr: The encoded array in @p is invalid
+ * %nfserr_inval: An unaligned extent found
+ * %nfserr_delay: Failed to allocate memory for @iomapp
+ */
+__be32
nfsd4_scsi_decode_layoutupdate(__be32 *p, u32 len, struct iomap **iomapp,
- u32 block_size)
+ int *nr_iomapsp, u32 block_size)
{
struct iomap *iomaps;
u32 nr_iomaps, expected, i;

if (len < sizeof(u32)) {
dprintk("%s: extent array too small: %u\n", __func__, len);
- return -EINVAL;
+ return nfserr_bad_xdr;
}

nr_iomaps = be32_to_cpup(p++);
@@ -201,13 +241,13 @@ nfsd4_scsi_decode_layoutupdate(__be32 *p, u32 len, struct iomap **iomapp,
if (len != expected) {
dprintk("%s: extent array size mismatch: %u/%u\n",
__func__, len, expected);
- return -EINVAL;
+ return nfserr_bad_xdr;
}

iomaps = kcalloc(nr_iomaps, sizeof(*iomaps), GFP_KERNEL);
if (!iomaps) {
dprintk("%s: failed to allocate extent array\n", __func__);
- return -ENOMEM;
+ return nfserr_delay;
}

for (i = 0; i < nr_iomaps; i++) {
@@ -229,8 +269,9 @@ nfsd4_scsi_decode_layoutupdate(__be32 *p, u32 len, struct iomap **iomapp,
}

*iomapp = iomaps;
- return nr_iomaps;
+ *nr_iomapsp = nr_iomaps;
+ return nfs_ok;
fail:
kfree(iomaps);
- return -EINVAL;
+ return nfserr_inval;
}
diff --git a/fs/nfsd/blocklayoutxdr.h b/fs/nfsd/blocklayoutxdr.h
index 4e28ac8f1127..15b3569f3d9a 100644
--- a/fs/nfsd/blocklayoutxdr.h
+++ b/fs/nfsd/blocklayoutxdr.h
@@ -54,9 +54,9 @@ __be32 nfsd4_block_encode_getdeviceinfo(struct xdr_stream *xdr,
const struct nfsd4_getdeviceinfo *gdp);
__be32 nfsd4_block_encode_layoutget(struct xdr_stream *xdr,
const struct nfsd4_layoutget *lgp);
-int nfsd4_block_decode_layoutupdate(__be32 *p, u32 len, struct iomap **iomapp,
- u32 block_size);
-int nfsd4_scsi_decode_layoutupdate(__be32 *p, u32 len, struct iomap **iomapp,
- u32 block_size);
+__be32 nfsd4_block_decode_layoutupdate(__be32 *p, u32 len,
+ struct iomap **iomapp, int *nr_iomapsp, u32 block_size);
+__be32 nfsd4_scsi_decode_layoutupdate(__be32 *p, u32 len,
+ struct iomap **iomapp, int *nr_iomapsp, u32 block_size);

#endif /* _NFSD_BLOCKLAYOUTXDR_H */
diff --git a/fs/nfsd/nfsd.h b/fs/nfsd/nfsd.h
index 1bfd0b4e9af7..3ffd2cac10ad 100644
--- a/fs/nfsd/nfsd.h
+++ b/fs/nfsd/nfsd.h
@@ -283,6 +283,7 @@ void nfsd_lockd_shutdown(void);
#define nfserr_cb_path_down cpu_to_be32(NFSERR_CB_PATH_DOWN)
#define nfserr_locked cpu_to_be32(NFSERR_LOCKED)
#define nfserr_wrongsec cpu_to_be32(NFSERR_WRONGSEC)
+#define nfserr_delay cpu_to_be32(NFS4ERR_DELAY)
#define nfserr_badiomode cpu_to_be32(NFS4ERR_BADIOMODE)
#define nfserr_badlayout cpu_to_be32(NFS4ERR_BADLAYOUT)
#define nfserr_bad_session_digest cpu_to_be32(NFS4ERR_BAD_SESSION_DIGEST)
--
2.43.0