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Commit 69bbd9c7 authored by Avi Kivity's avatar Avi Kivity Committed by J. Bruce Fields
Browse files

nfs: fix nfs4d readlink truncated packet 



XDR requires 4-byte alignment; nfs4d READLINK reply writes out the padding,
but truncates the packet to the padding-less size.

Fix by taking the padding into consideration when truncating the packet.

Symptoms:

	# ll /mnt/
	ls: cannot read symbolic link /mnt/test: Input/output error
	total 4
	-rw-r--r--. 1 root root  0 Jun 14 01:21 123456
	lrwxrwxrwx. 1 root root  6 Jul  2 03:33 test
	drwxr-xr-x. 1 root root  0 Jul  2 23:50 tmp
	drwxr-xr-x. 1 root root 60 Jul  2 23:44 tree

Signed-off-by: default avatarAvi Kivity <avi@cloudius-systems.com>
Fixes: 476a7b1f (nfsd4: don't treat readlink like a zero-copy operation)
Reviewed-by: default avatarKinglong Mee <kinglongmee@gmail.com>
Signed-off-by: default avatarJ. Bruce Fields <bfields@redhat.com>
parent 76f47128

fs/nfsd/nfs4xdr.c

+1 −1
Original line number Original line Diff line number Diff line
@@ -3278,7 +3278,7 @@ nfsd4_encode_readlink(struct nfsd4_compoundres *resp, __be32 nfserr, struct nfsd 




	wire_count = htonl(maxcount);

	wire_count = htonl(maxcount);

	write_bytes_to_xdr_buf(xdr->buf, length_offset, &wire_count, 4);

	write_bytes_to_xdr_buf(xdr->buf, length_offset, &wire_count, 4);

	xdr_truncate_encode(xdr, length_offset + 4 + maxcount);

	xdr_truncate_encode(xdr, length_offset + 4 + ALIGN(maxcount, 4));

	if (maxcount & 3)

	if (maxcount & 3)

		write_bytes_to_xdr_buf(xdr->buf, length_offset + 4 + maxcount,

		write_bytes_to_xdr_buf(xdr->buf, length_offset + 4 + maxcount,

						&zero, 4 - (maxcount&3));

						&zero, 4 - (maxcount&3));