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authorMurphy Zhou <jencce.kernel@gmail.com>2019-04-04 09:57:11 +0300
committerJ. Bruce Fields <bfields@redhat.com>2019-04-06 02:57:24 +0300
commit3c86794ac0e6582eea7733619d58ea150198502f (patch)
tree097ea6e5d63a6fc920c1c0b30f7de874f148b4cf /fs/nfsd
parentd58431eacb226222430940134d97bfd72f292fcd (diff)
downloadlinux-3c86794ac0e6582eea7733619d58ea150198502f.tar.xz
nfsd/nfsd3_proc_readdir: fix buffer count and page pointers
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> Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Diffstat (limited to 'fs/nfsd')
-rw-r--r--fs/nfsd/nfs3proc.c17
-rw-r--r--fs/nfsd/nfs3xdr.c11
2 files changed, 24 insertions, 4 deletions
diff --git a/fs/nfsd/nfs3proc.c b/fs/nfsd/nfs3proc.c
index 8f933e84cec1..9bc32af4e2da 100644
--- a/fs/nfsd/nfs3proc.c
+++ b/fs/nfsd/nfs3proc.c
@@ -442,7 +442,9 @@ nfsd3_proc_readdir(struct svc_rqst *rqstp)
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 @@ nfsd3_proc_readdir(struct svc_rqst *rqstp)
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 93fea246f676..8d789124ed3c 100644
--- a/fs/nfsd/nfs3xdr.c
+++ b/fs/nfsd/nfs3xdr.c
@@ -573,6 +573,7 @@ int
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 @@ nfs3svc_decode_readdirargs(struct svc_rqst *rqstp, __be32 *p)
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);
}