mirror of
https://github.com/torvalds/linux.git
synced 2024-12-26 04:42:12 +00:00
303a780520
I found that the read code might send multiple requests using the same
nfs_pgio_header, but nfs4_proc_read_setup() is only called once. This is
how we ended up occasionally double-freeing the scratch buffer, but also
means we set a NULL pointer but non-zero length to the xdr scratch
buffer. This results in an oops the first time decoding needs to copy
something to scratch, which frequently happens when decoding READ_PLUS
hole segments.
I fix this by moving scratch handling into the pageio read code. I
provide a function to allocate scratch space for decoding read replies,
and free the scratch buffer when the nfs_pgio_header is freed.
Fixes: fbd2a05f29
(NFSv4.2: Rework scratch handling for READ_PLUS)
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
459 lines
11 KiB
C
459 lines
11 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
|
|
/*
|
|
* linux/fs/nfs/read.c
|
|
*
|
|
* Block I/O for NFS
|
|
*
|
|
* Partial copy of Linus' read cache modifications to fs/nfs/file.c
|
|
* modified for async RPC by okir@monad.swb.de
|
|
*/
|
|
|
|
#include <linux/time.h>
|
|
#include <linux/kernel.h>
|
|
#include <linux/errno.h>
|
|
#include <linux/fcntl.h>
|
|
#include <linux/stat.h>
|
|
#include <linux/mm.h>
|
|
#include <linux/slab.h>
|
|
#include <linux/task_io_accounting_ops.h>
|
|
#include <linux/pagemap.h>
|
|
#include <linux/sunrpc/clnt.h>
|
|
#include <linux/nfs_fs.h>
|
|
#include <linux/nfs_page.h>
|
|
#include <linux/module.h>
|
|
|
|
#include "nfs4_fs.h"
|
|
#include "internal.h"
|
|
#include "iostat.h"
|
|
#include "fscache.h"
|
|
#include "pnfs.h"
|
|
#include "nfstrace.h"
|
|
|
|
#define NFSDBG_FACILITY NFSDBG_PAGECACHE
|
|
|
|
const struct nfs_pgio_completion_ops nfs_async_read_completion_ops;
|
|
static const struct nfs_rw_ops nfs_rw_read_ops;
|
|
|
|
static struct kmem_cache *nfs_rdata_cachep;
|
|
|
|
static struct nfs_pgio_header *nfs_readhdr_alloc(void)
|
|
{
|
|
struct nfs_pgio_header *p = kmem_cache_zalloc(nfs_rdata_cachep, GFP_KERNEL);
|
|
|
|
if (p)
|
|
p->rw_mode = FMODE_READ;
|
|
return p;
|
|
}
|
|
|
|
static void nfs_readhdr_free(struct nfs_pgio_header *rhdr)
|
|
{
|
|
if (rhdr->res.scratch != NULL)
|
|
kfree(rhdr->res.scratch);
|
|
kmem_cache_free(nfs_rdata_cachep, rhdr);
|
|
}
|
|
|
|
static int nfs_return_empty_folio(struct folio *folio)
|
|
{
|
|
folio_zero_segment(folio, 0, folio_size(folio));
|
|
folio_mark_uptodate(folio);
|
|
folio_unlock(folio);
|
|
return 0;
|
|
}
|
|
|
|
void nfs_pageio_init_read(struct nfs_pageio_descriptor *pgio,
|
|
struct inode *inode, bool force_mds,
|
|
const struct nfs_pgio_completion_ops *compl_ops)
|
|
{
|
|
struct nfs_server *server = NFS_SERVER(inode);
|
|
const struct nfs_pageio_ops *pg_ops = &nfs_pgio_rw_ops;
|
|
|
|
#ifdef CONFIG_NFS_V4_1
|
|
if (server->pnfs_curr_ld && !force_mds)
|
|
pg_ops = server->pnfs_curr_ld->pg_read_ops;
|
|
#endif
|
|
nfs_pageio_init(pgio, inode, pg_ops, compl_ops, &nfs_rw_read_ops,
|
|
server->rsize, 0);
|
|
}
|
|
EXPORT_SYMBOL_GPL(nfs_pageio_init_read);
|
|
|
|
void nfs_pageio_complete_read(struct nfs_pageio_descriptor *pgio)
|
|
{
|
|
struct nfs_pgio_mirror *pgm;
|
|
unsigned long npages;
|
|
|
|
nfs_pageio_complete(pgio);
|
|
|
|
/* It doesn't make sense to do mirrored reads! */
|
|
WARN_ON_ONCE(pgio->pg_mirror_count != 1);
|
|
|
|
pgm = &pgio->pg_mirrors[0];
|
|
NFS_I(pgio->pg_inode)->read_io += pgm->pg_bytes_written;
|
|
npages = (pgm->pg_bytes_written + PAGE_SIZE - 1) >> PAGE_SHIFT;
|
|
nfs_add_stats(pgio->pg_inode, NFSIOS_READPAGES, npages);
|
|
}
|
|
|
|
|
|
void nfs_pageio_reset_read_mds(struct nfs_pageio_descriptor *pgio)
|
|
{
|
|
struct nfs_pgio_mirror *mirror;
|
|
|
|
if (pgio->pg_ops && pgio->pg_ops->pg_cleanup)
|
|
pgio->pg_ops->pg_cleanup(pgio);
|
|
|
|
pgio->pg_ops = &nfs_pgio_rw_ops;
|
|
|
|
/* read path should never have more than one mirror */
|
|
WARN_ON_ONCE(pgio->pg_mirror_count != 1);
|
|
|
|
mirror = &pgio->pg_mirrors[0];
|
|
mirror->pg_bsize = NFS_SERVER(pgio->pg_inode)->rsize;
|
|
}
|
|
EXPORT_SYMBOL_GPL(nfs_pageio_reset_read_mds);
|
|
|
|
bool nfs_read_alloc_scratch(struct nfs_pgio_header *hdr, size_t size)
|
|
{
|
|
WARN_ON(hdr->res.scratch != NULL);
|
|
hdr->res.scratch = kmalloc(size, GFP_KERNEL);
|
|
return hdr->res.scratch != NULL;
|
|
}
|
|
EXPORT_SYMBOL_GPL(nfs_read_alloc_scratch);
|
|
|
|
static void nfs_readpage_release(struct nfs_page *req, int error)
|
|
{
|
|
struct folio *folio = nfs_page_to_folio(req);
|
|
|
|
if (nfs_error_is_fatal_on_server(error) && error != -ETIMEDOUT)
|
|
folio_set_error(folio);
|
|
if (nfs_page_group_sync_on_bit(req, PG_UNLOCKPAGE))
|
|
if (nfs_netfs_folio_unlock(folio))
|
|
folio_unlock(folio);
|
|
|
|
nfs_release_request(req);
|
|
}
|
|
|
|
static void nfs_page_group_set_uptodate(struct nfs_page *req)
|
|
{
|
|
if (nfs_page_group_sync_on_bit(req, PG_UPTODATE))
|
|
folio_mark_uptodate(nfs_page_to_folio(req));
|
|
}
|
|
|
|
static void nfs_read_completion(struct nfs_pgio_header *hdr)
|
|
{
|
|
unsigned long bytes = 0;
|
|
int error;
|
|
|
|
if (test_bit(NFS_IOHDR_REDO, &hdr->flags))
|
|
goto out;
|
|
while (!list_empty(&hdr->pages)) {
|
|
struct nfs_page *req = nfs_list_entry(hdr->pages.next);
|
|
struct folio *folio = nfs_page_to_folio(req);
|
|
unsigned long start = req->wb_pgbase;
|
|
unsigned long end = req->wb_pgbase + req->wb_bytes;
|
|
|
|
if (test_bit(NFS_IOHDR_EOF, &hdr->flags)) {
|
|
/* note: regions of the page not covered by a
|
|
* request are zeroed in nfs_read_add_folio
|
|
*/
|
|
if (bytes > hdr->good_bytes) {
|
|
/* nothing in this request was good, so zero
|
|
* the full extent of the request */
|
|
folio_zero_segment(folio, start, end);
|
|
|
|
} else if (hdr->good_bytes - bytes < req->wb_bytes) {
|
|
/* part of this request has good bytes, but
|
|
* not all. zero the bad bytes */
|
|
start += hdr->good_bytes - bytes;
|
|
WARN_ON(start < req->wb_pgbase);
|
|
folio_zero_segment(folio, start, end);
|
|
}
|
|
}
|
|
error = 0;
|
|
bytes += req->wb_bytes;
|
|
if (test_bit(NFS_IOHDR_ERROR, &hdr->flags)) {
|
|
if (bytes <= hdr->good_bytes)
|
|
nfs_page_group_set_uptodate(req);
|
|
else {
|
|
error = hdr->error;
|
|
xchg(&nfs_req_openctx(req)->error, error);
|
|
}
|
|
} else
|
|
nfs_page_group_set_uptodate(req);
|
|
nfs_list_remove_request(req);
|
|
nfs_readpage_release(req, error);
|
|
}
|
|
nfs_netfs_read_completion(hdr);
|
|
|
|
out:
|
|
hdr->release(hdr);
|
|
}
|
|
|
|
static void nfs_initiate_read(struct nfs_pgio_header *hdr,
|
|
struct rpc_message *msg,
|
|
const struct nfs_rpc_ops *rpc_ops,
|
|
struct rpc_task_setup *task_setup_data, int how)
|
|
{
|
|
rpc_ops->read_setup(hdr, msg);
|
|
nfs_netfs_initiate_read(hdr);
|
|
trace_nfs_initiate_read(hdr);
|
|
}
|
|
|
|
static void
|
|
nfs_async_read_error(struct list_head *head, int error)
|
|
{
|
|
struct nfs_page *req;
|
|
|
|
while (!list_empty(head)) {
|
|
req = nfs_list_entry(head->next);
|
|
nfs_list_remove_request(req);
|
|
nfs_readpage_release(req, error);
|
|
}
|
|
}
|
|
|
|
const struct nfs_pgio_completion_ops nfs_async_read_completion_ops = {
|
|
.error_cleanup = nfs_async_read_error,
|
|
.completion = nfs_read_completion,
|
|
};
|
|
|
|
/*
|
|
* This is the callback from RPC telling us whether a reply was
|
|
* received or some error occurred (timeout or socket shutdown).
|
|
*/
|
|
static int nfs_readpage_done(struct rpc_task *task,
|
|
struct nfs_pgio_header *hdr,
|
|
struct inode *inode)
|
|
{
|
|
int status = NFS_PROTO(inode)->read_done(task, hdr);
|
|
if (status != 0)
|
|
return status;
|
|
|
|
nfs_add_stats(inode, NFSIOS_SERVERREADBYTES, hdr->res.count);
|
|
trace_nfs_readpage_done(task, hdr);
|
|
|
|
if (task->tk_status == -ESTALE) {
|
|
nfs_set_inode_stale(inode);
|
|
nfs_mark_for_revalidate(inode);
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
static void nfs_readpage_retry(struct rpc_task *task,
|
|
struct nfs_pgio_header *hdr)
|
|
{
|
|
struct nfs_pgio_args *argp = &hdr->args;
|
|
struct nfs_pgio_res *resp = &hdr->res;
|
|
|
|
/* This is a short read! */
|
|
nfs_inc_stats(hdr->inode, NFSIOS_SHORTREAD);
|
|
trace_nfs_readpage_short(task, hdr);
|
|
|
|
/* Has the server at least made some progress? */
|
|
if (resp->count == 0) {
|
|
nfs_set_pgio_error(hdr, -EIO, argp->offset);
|
|
return;
|
|
}
|
|
|
|
/* For non rpc-based layout drivers, retry-through-MDS */
|
|
if (!task->tk_ops) {
|
|
hdr->pnfs_error = -EAGAIN;
|
|
return;
|
|
}
|
|
|
|
/* Yes, so retry the read at the end of the hdr */
|
|
hdr->mds_offset += resp->count;
|
|
argp->offset += resp->count;
|
|
argp->pgbase += resp->count;
|
|
argp->count -= resp->count;
|
|
resp->count = 0;
|
|
resp->eof = 0;
|
|
rpc_restart_call_prepare(task);
|
|
}
|
|
|
|
static void nfs_readpage_result(struct rpc_task *task,
|
|
struct nfs_pgio_header *hdr)
|
|
{
|
|
if (hdr->res.eof) {
|
|
loff_t pos = hdr->args.offset + hdr->res.count;
|
|
unsigned int new = pos - hdr->io_start;
|
|
|
|
if (hdr->good_bytes > new) {
|
|
hdr->good_bytes = new;
|
|
set_bit(NFS_IOHDR_EOF, &hdr->flags);
|
|
clear_bit(NFS_IOHDR_ERROR, &hdr->flags);
|
|
}
|
|
} else if (hdr->res.count < hdr->args.count)
|
|
nfs_readpage_retry(task, hdr);
|
|
}
|
|
|
|
int nfs_read_add_folio(struct nfs_pageio_descriptor *pgio,
|
|
struct nfs_open_context *ctx,
|
|
struct folio *folio)
|
|
{
|
|
struct inode *inode = folio_file_mapping(folio)->host;
|
|
struct nfs_server *server = NFS_SERVER(inode);
|
|
size_t fsize = folio_size(folio);
|
|
unsigned int rsize = server->rsize;
|
|
struct nfs_page *new;
|
|
unsigned int len, aligned_len;
|
|
int error;
|
|
|
|
len = nfs_folio_length(folio);
|
|
if (len == 0)
|
|
return nfs_return_empty_folio(folio);
|
|
|
|
aligned_len = min_t(unsigned int, ALIGN(len, rsize), fsize);
|
|
|
|
new = nfs_page_create_from_folio(ctx, folio, 0, aligned_len);
|
|
if (IS_ERR(new)) {
|
|
error = PTR_ERR(new);
|
|
goto out;
|
|
}
|
|
|
|
if (len < fsize)
|
|
folio_zero_segment(folio, len, fsize);
|
|
if (!nfs_pageio_add_request(pgio, new)) {
|
|
nfs_list_remove_request(new);
|
|
error = pgio->pg_error;
|
|
nfs_readpage_release(new, error);
|
|
goto out;
|
|
}
|
|
return 0;
|
|
out:
|
|
return error;
|
|
}
|
|
|
|
/*
|
|
* Read a page over NFS.
|
|
* We read the page synchronously in the following case:
|
|
* - The error flag is set for this page. This happens only when a
|
|
* previous async read operation failed.
|
|
*/
|
|
int nfs_read_folio(struct file *file, struct folio *folio)
|
|
{
|
|
struct inode *inode = file_inode(file);
|
|
struct nfs_pageio_descriptor pgio;
|
|
struct nfs_open_context *ctx;
|
|
int ret;
|
|
|
|
trace_nfs_aop_readpage(inode, folio);
|
|
nfs_inc_stats(inode, NFSIOS_VFSREADPAGE);
|
|
task_io_account_read(folio_size(folio));
|
|
|
|
/*
|
|
* Try to flush any pending writes to the file..
|
|
*
|
|
* NOTE! Because we own the folio lock, there cannot
|
|
* be any new pending writes generated at this point
|
|
* for this folio (other folios can be written to).
|
|
*/
|
|
ret = nfs_wb_folio(inode, folio);
|
|
if (ret)
|
|
goto out_unlock;
|
|
if (folio_test_uptodate(folio))
|
|
goto out_unlock;
|
|
|
|
ret = -ESTALE;
|
|
if (NFS_STALE(inode))
|
|
goto out_unlock;
|
|
|
|
ret = nfs_netfs_read_folio(file, folio);
|
|
if (!ret)
|
|
goto out;
|
|
|
|
ctx = get_nfs_open_context(nfs_file_open_context(file));
|
|
|
|
xchg(&ctx->error, 0);
|
|
nfs_pageio_init_read(&pgio, inode, false,
|
|
&nfs_async_read_completion_ops);
|
|
|
|
ret = nfs_read_add_folio(&pgio, ctx, folio);
|
|
if (ret)
|
|
goto out_put;
|
|
|
|
nfs_pageio_complete_read(&pgio);
|
|
ret = pgio.pg_error < 0 ? pgio.pg_error : 0;
|
|
if (!ret) {
|
|
ret = folio_wait_locked_killable(folio);
|
|
if (!folio_test_uptodate(folio) && !ret)
|
|
ret = xchg(&ctx->error, 0);
|
|
}
|
|
out_put:
|
|
put_nfs_open_context(ctx);
|
|
out:
|
|
trace_nfs_aop_readpage_done(inode, folio, ret);
|
|
return ret;
|
|
out_unlock:
|
|
folio_unlock(folio);
|
|
goto out;
|
|
}
|
|
|
|
void nfs_readahead(struct readahead_control *ractl)
|
|
{
|
|
struct nfs_pageio_descriptor pgio;
|
|
struct nfs_open_context *ctx;
|
|
unsigned int nr_pages = readahead_count(ractl);
|
|
struct file *file = ractl->file;
|
|
struct inode *inode = ractl->mapping->host;
|
|
struct folio *folio;
|
|
int ret;
|
|
|
|
trace_nfs_aop_readahead(inode, readahead_pos(ractl), nr_pages);
|
|
nfs_inc_stats(inode, NFSIOS_VFSREADPAGES);
|
|
task_io_account_read(readahead_length(ractl));
|
|
|
|
ret = -ESTALE;
|
|
if (NFS_STALE(inode))
|
|
goto out;
|
|
|
|
ret = nfs_netfs_readahead(ractl);
|
|
if (!ret)
|
|
goto out;
|
|
|
|
if (file == NULL) {
|
|
ret = -EBADF;
|
|
ctx = nfs_find_open_context(inode, NULL, FMODE_READ);
|
|
if (ctx == NULL)
|
|
goto out;
|
|
} else
|
|
ctx = get_nfs_open_context(nfs_file_open_context(file));
|
|
|
|
nfs_pageio_init_read(&pgio, inode, false,
|
|
&nfs_async_read_completion_ops);
|
|
|
|
while ((folio = readahead_folio(ractl)) != NULL) {
|
|
ret = nfs_read_add_folio(&pgio, ctx, folio);
|
|
if (ret)
|
|
break;
|
|
}
|
|
|
|
nfs_pageio_complete_read(&pgio);
|
|
|
|
put_nfs_open_context(ctx);
|
|
out:
|
|
trace_nfs_aop_readahead_done(inode, nr_pages, ret);
|
|
}
|
|
|
|
int __init nfs_init_readpagecache(void)
|
|
{
|
|
nfs_rdata_cachep = kmem_cache_create("nfs_read_data",
|
|
sizeof(struct nfs_pgio_header),
|
|
0, SLAB_HWCACHE_ALIGN,
|
|
NULL);
|
|
if (nfs_rdata_cachep == NULL)
|
|
return -ENOMEM;
|
|
|
|
return 0;
|
|
}
|
|
|
|
void nfs_destroy_readpagecache(void)
|
|
{
|
|
kmem_cache_destroy(nfs_rdata_cachep);
|
|
}
|
|
|
|
static const struct nfs_rw_ops nfs_rw_read_ops = {
|
|
.rw_alloc_header = nfs_readhdr_alloc,
|
|
.rw_free_header = nfs_readhdr_free,
|
|
.rw_done = nfs_readpage_done,
|
|
.rw_result = nfs_readpage_result,
|
|
.rw_initiate = nfs_initiate_read,
|
|
};
|