On 7/1/2014 19:21, Avi Kivity wrote: > On 06/26/2014 05:23 PM, Avi Kivity wrote: >> 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. >> > > Ping. I should have mentioned that without this, readlink() returns an I/O error on the client. Yes, I got [root@localhost ~]# 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 [root@localhost ~]# It's introduced by commit 476a7b1f4b2c (nfsd4: don't treat readlink like a zero-copy operation). > >> Signed-off-by: Avi Kivity <avi@xxxxxxxxxxxxxxxxxxxx> >> --- >> fs/nfsd/nfs4xdr.c | 2 +- >> 1 file changed, 1 insertion(+), 1 deletion(-) >> >> diff --git a/fs/nfsd/nfs4xdr.c b/fs/nfsd/nfs4xdr.c >> index 83baf2b..cba93ea 100644 >> --- a/fs/nfsd/nfs4xdr.c >> +++ b/fs/nfsd/nfs4xdr.c >> @@ -3267,7 +3267,7 @@ nfsd4_encode_readlink(struct nfsd4_compoundres *resp, __be32 nfserr, struct nfsd >> wire_count = htonl(maxcount); >> 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)); NFSD uses (XDR_QUADLEN(maxcount) << 2)) usually. Anyway, it's a nice fix. Reviewed-by: Kinglong Mee <kinglongmee@xxxxxxxxx> thanks, Kinglong Mee -- To unsubscribe from this list: send the line "unsubscribe linux-nfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
