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Date: Sun, 09 Sep 2012 23:41:56 +0100
From: Ben Hutchings <ben@...adent.org.uk>
To: linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc: torvalds@...ux-foundation.org, akpm@...ux-foundation.org,
alan@...rguk.ukuu.org.uk, Idan Kedar <idank@...ian.com>,
Benny Halevy <bhalevy@...ian.com>,
Trond Myklebust <Trond.Myklebust@...app.com>
Subject: [ 06/95] pnfs: defer release of pages in layoutget
3.2-stable review patch. If anyone has any objections, please let me know.
------------------
From: Idan Kedar <idank@...ian.com>
commit 8554116e17eef055d9dd58a94b3427cb2ad1c317 upstream.
we have encountered a bug whereby reading a lot of files (copying
fedora's /bin) from a pNFS mount and hitting Ctrl+C in the middle caused
a general protection fault in xdr_shrink_bufhead. this function is
called when decoding the response from LAYOUTGET. the decoding is done
by a worker thread, and the caller of LAYOUTGET waits for the worker
thread to complete.
hitting Ctrl+C caused the synchronous wait to end and the next thing the
caller does is to free the pages, so when the worker thread calls
xdr_shrink_bufhead, the pages are gone. therefore, the cleanup of these
pages has been moved to nfs4_layoutget_release.
Signed-off-by: Idan Kedar <idank@...ian.com>
Signed-off-by: Benny Halevy <bhalevy@...ian.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@...app.com>
Signed-off-by: Ben Hutchings <ben@...adent.org.uk>
---
fs/nfs/nfs4proc.c | 57 ++++++++++++++++++++++++++++++++++++++++++++++++++++-
fs/nfs/pnfs.c | 39 +-----------------------------------
fs/nfs/pnfs.h | 2 +-
3 files changed, 58 insertions(+), 40 deletions(-)
--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -5769,11 +5769,58 @@ static void nfs4_layoutget_done(struct r
dprintk("<-- %s\n", __func__);
}
+static size_t max_response_pages(struct nfs_server *server)
+{
+ u32 max_resp_sz = server->nfs_client->cl_session->fc_attrs.max_resp_sz;
+ return nfs_page_array_len(0, max_resp_sz);
+}
+
+static void nfs4_free_pages(struct page **pages, size_t size)
+{
+ int i;
+
+ if (!pages)
+ return;
+
+ for (i = 0; i < size; i++) {
+ if (!pages[i])
+ break;
+ __free_page(pages[i]);
+ }
+ kfree(pages);
+}
+
+static struct page **nfs4_alloc_pages(size_t size, gfp_t gfp_flags)
+{
+ struct page **pages;
+ int i;
+
+ pages = kcalloc(size, sizeof(struct page *), gfp_flags);
+ if (!pages) {
+ dprintk("%s: can't alloc array of %zu pages\n", __func__, size);
+ return NULL;
+ }
+
+ for (i = 0; i < size; i++) {
+ pages[i] = alloc_page(gfp_flags);
+ if (!pages[i]) {
+ dprintk("%s: failed to allocate page\n", __func__);
+ nfs4_free_pages(pages, size);
+ return NULL;
+ }
+ }
+
+ return pages;
+}
+
static void nfs4_layoutget_release(void *calldata)
{
struct nfs4_layoutget *lgp = calldata;
+ struct nfs_server *server = NFS_SERVER(lgp->args.inode);
+ size_t max_pages = max_response_pages(server);
dprintk("--> %s\n", __func__);
+ nfs4_free_pages(lgp->args.layout.pages, max_pages);
put_nfs_open_context(lgp->args.ctx);
kfree(calldata);
dprintk("<-- %s\n", __func__);
@@ -5785,9 +5832,10 @@ static const struct rpc_call_ops nfs4_la
.rpc_release = nfs4_layoutget_release,
};
-int nfs4_proc_layoutget(struct nfs4_layoutget *lgp)
+int nfs4_proc_layoutget(struct nfs4_layoutget *lgp, gfp_t gfp_flags)
{
struct nfs_server *server = NFS_SERVER(lgp->args.inode);
+ size_t max_pages = max_response_pages(server);
struct rpc_task *task;
struct rpc_message msg = {
.rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_LAYOUTGET],
@@ -5805,6 +5853,13 @@ int nfs4_proc_layoutget(struct nfs4_layo
dprintk("--> %s\n", __func__);
+ lgp->args.layout.pages = nfs4_alloc_pages(max_pages, gfp_flags);
+ if (!lgp->args.layout.pages) {
+ nfs4_layoutget_release(lgp);
+ return -ENOMEM;
+ }
+ lgp->args.layout.pglen = max_pages * PAGE_SIZE;
+
lgp->res.layoutp = &lgp->args.layout;
lgp->res.seq_res.sr_slot = NULL;
task = rpc_run_task(&task_setup_data);
--- a/fs/nfs/pnfs.c
+++ b/fs/nfs/pnfs.c
@@ -575,9 +575,6 @@ send_layoutget(struct pnfs_layout_hdr *l
struct nfs_server *server = NFS_SERVER(ino);
struct nfs4_layoutget *lgp;
struct pnfs_layout_segment *lseg = NULL;
- struct page **pages = NULL;
- int i;
- u32 max_resp_sz, max_pages;
dprintk("--> %s\n", __func__);
@@ -586,20 +583,6 @@ send_layoutget(struct pnfs_layout_hdr *l
if (lgp == NULL)
return NULL;
- /* allocate pages for xdr post processing */
- max_resp_sz = server->nfs_client->cl_session->fc_attrs.max_resp_sz;
- max_pages = nfs_page_array_len(0, max_resp_sz);
-
- pages = kcalloc(max_pages, sizeof(struct page *), gfp_flags);
- if (!pages)
- goto out_err_free;
-
- for (i = 0; i < max_pages; i++) {
- pages[i] = alloc_page(gfp_flags);
- if (!pages[i])
- goto out_err_free;
- }
-
lgp->args.minlength = PAGE_CACHE_SIZE;
if (lgp->args.minlength > range->length)
lgp->args.minlength = range->length;
@@ -608,39 +591,19 @@ send_layoutget(struct pnfs_layout_hdr *l
lgp->args.type = server->pnfs_curr_ld->id;
lgp->args.inode = ino;
lgp->args.ctx = get_nfs_open_context(ctx);
- lgp->args.layout.pages = pages;
- lgp->args.layout.pglen = max_pages * PAGE_SIZE;
lgp->lsegpp = &lseg;
lgp->gfp_flags = gfp_flags;
/* Synchronously retrieve layout information from server and
* store in lseg.
*/
- nfs4_proc_layoutget(lgp);
+ nfs4_proc_layoutget(lgp, gfp_flags);
if (!lseg) {
/* remember that LAYOUTGET failed and suspend trying */
set_bit(lo_fail_bit(range->iomode), &lo->plh_flags);
}
- /* free xdr pages */
- for (i = 0; i < max_pages; i++)
- __free_page(pages[i]);
- kfree(pages);
-
return lseg;
-
-out_err_free:
- /* free any allocated xdr pages, lgp as it's not used */
- if (pages) {
- for (i = 0; i < max_pages; i++) {
- if (!pages[i])
- break;
- __free_page(pages[i]);
- }
- kfree(pages);
- }
- kfree(lgp);
- return NULL;
}
/* Initiates a LAYOUTRETURN(FILE) */
--- a/fs/nfs/pnfs.h
+++ b/fs/nfs/pnfs.h
@@ -162,7 +162,7 @@ extern int nfs4_proc_getdevicelist(struc
struct pnfs_devicelist *devlist);
extern int nfs4_proc_getdeviceinfo(struct nfs_server *server,
struct pnfs_device *dev);
-extern int nfs4_proc_layoutget(struct nfs4_layoutget *lgp);
+extern int nfs4_proc_layoutget(struct nfs4_layoutget *lgp, gfp_t gfp_flags);
extern int nfs4_proc_layoutreturn(struct nfs4_layoutreturn *lrp);
/* pnfs.c */
--
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