From: Murphy Zhou <jencce.kernel@gmail.com>
To: linux-nfs@vger.kernel.org, neilb@suse.com
Cc: bfields@fieldses.org, jlayton@kernel.org,
Murphy Zhou <jencce.kernel@gmail.com>
Subject: [PATCH v2] nfsd/nfsd3_proc_readdir: fix buffer count and page pointers
Date: Thu, 4 Apr 2019 14:57:11 +0800 [thread overview]
Message-ID: <20190404065711.19763-1-jencce.kernel@gmail.com> (raw)
After this commit
f875a79 nfsd: allow nfsv3 readdir request to be larger.
nfsv3 readdir request size can be larger than PAGE_SIZE. So if the
directory been read is large enough, we can use multiple pages
in rq_respages. Update buffer count and page pointers like we do
in readdirplus to make this happen.
Now listing a directory within 3000 files will panic because we
are counting in a wrong way and would write on random page.
Fixes: f875a79 "nfsd: allow nfsv3 readdir request to be larger"
Signed-off-by: Murphy Zhou <jencce.kernel@gmail.com>
---
v2:
fix nfs3svc_decode_readdirargs to set page pointers like decode_readdirplusargs
do not test pointers in encode_entry as we've fixed them when decoding
fs/nfsd/nfs3proc.c | 17 +++++++++++++++--
fs/nfsd/nfs3xdr.c | 11 +++++++++--
2 files changed, 24 insertions(+), 4 deletions(-)
diff --git a/fs/nfsd/nfs3proc.c b/fs/nfsd/nfs3proc.c
index 8f933e8..9bc32af 100644
--- a/fs/nfsd/nfs3proc.c
+++ b/fs/nfsd/nfs3proc.c
@@ -442,7 +442,9 @@
struct nfsd3_readdirargs *argp = rqstp->rq_argp;
struct nfsd3_readdirres *resp = rqstp->rq_resp;
__be32 nfserr;
- int count;
+ int count = 0;
+ struct page **p;
+ caddr_t page_addr = NULL;
dprintk("nfsd: READDIR(3) %s %d bytes at %d\n",
SVCFH_fmt(&argp->fh),
@@ -462,7 +464,18 @@
nfserr = nfsd_readdir(rqstp, &resp->fh, (loff_t*) &argp->cookie,
&resp->common, nfs3svc_encode_entry);
memcpy(resp->verf, argp->verf, 8);
- resp->count = resp->buffer - argp->buffer;
+ count = 0;
+ for (p = rqstp->rq_respages + 1; p < rqstp->rq_next_page; p++) {
+ page_addr = page_address(*p);
+
+ if (((caddr_t)resp->buffer >= page_addr) &&
+ ((caddr_t)resp->buffer < page_addr + PAGE_SIZE)) {
+ count += (caddr_t)resp->buffer - page_addr;
+ break;
+ }
+ count += PAGE_SIZE;
+ }
+ resp->count = count >> 2;
if (resp->offset) {
loff_t offset = argp->cookie;
diff --git a/fs/nfsd/nfs3xdr.c b/fs/nfsd/nfs3xdr.c
index 93fea24..8d78912 100644
--- a/fs/nfsd/nfs3xdr.c
+++ b/fs/nfsd/nfs3xdr.c
@@ -573,6 +573,7 @@ void fill_post_wcc(struct svc_fh *fhp)
nfs3svc_decode_readdirargs(struct svc_rqst *rqstp, __be32 *p)
{
struct nfsd3_readdirargs *args = rqstp->rq_argp;
+ int len;
u32 max_blocksize = svc_max_payload(rqstp);
p = decode_fh(p, &args->fh);
@@ -582,8 +583,14 @@ void fill_post_wcc(struct svc_fh *fhp)
args->verf = p; p += 2;
args->dircount = ~0;
args->count = ntohl(*p++);
- args->count = min_t(u32, args->count, max_blocksize);
- args->buffer = page_address(*(rqstp->rq_next_page++));
+ len = args->count = min_t(u32, args->count, max_blocksize);
+
+ while (len > 0) {
+ struct page *p = *(rqstp->rq_next_page++);
+ if (!args->buffer)
+ args->buffer = page_address(p);
+ len -= PAGE_SIZE;
+ }
return xdr_argsize_check(rqstp, p);
}
--
1.8.3.1
next reply other threads:[~2019-04-04 6:57 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-04-04 6:57 Murphy Zhou [this message]
2019-04-04 22:47 ` [PATCH v2] nfsd/nfsd3_proc_readdir: fix buffer count and page pointers NeilBrown
[not found] ` <CADJHv_t_Cqav7Wr8dHo0kBBX3-ws0qVDcYi4HZt26Dq8jO+DGQ@mail.gmail.com>
[not found] ` <CADJHv_u-F+D-p-uhJzxKTwQijZHe8wHfcyC97tjAgOO_ToJYHw@mail.gmail.com>
2019-04-05 6:44 ` Murphy Zhou
2019-04-05 23:56 ` J. Bruce Fields
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