mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-08-26 10:49:33 +00:00
![Trond Myklebust](/assets/img/avatar_default.png)
We can't call nfs_readdata_release()/nfs_writedata_release() without first initialising and referencing args.context. Doing so inside nfs_direct_read_schedule_segment()/nfs_direct_write_schedule_segment() causes an Oops. We should rather be calling nfs_readdata_free()/nfs_writedata_free() in those cases. Looking at the O_DIRECT code, the "struct nfs_direct_req" is already referencing the nfs_open_context for us. Since the readdata and writedata structures carry a reference to that, we can simplify things by getting rid of the extra nfs_open_context references, so that we can replace all instances of nfs_readdata_release()/nfs_writedata_release(). Reported-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com> Tested-by: Catalin Marinas <catalin.marinas@arm.com> Cc: stable@kernel.org Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
670 lines
17 KiB
C
670 lines
17 KiB
C
/*
|
|
* 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/pagemap.h>
|
|
#include <linux/sunrpc/clnt.h>
|
|
#include <linux/nfs_fs.h>
|
|
#include <linux/nfs_page.h>
|
|
|
|
#include <asm/system.h>
|
|
|
|
#include "nfs4_fs.h"
|
|
#include "internal.h"
|
|
#include "iostat.h"
|
|
#include "fscache.h"
|
|
|
|
#define NFSDBG_FACILITY NFSDBG_PAGECACHE
|
|
|
|
static int nfs_pagein_multi(struct inode *, struct list_head *, unsigned int, size_t, int);
|
|
static int nfs_pagein_one(struct inode *, struct list_head *, unsigned int, size_t, int);
|
|
static const struct rpc_call_ops nfs_read_partial_ops;
|
|
static const struct rpc_call_ops nfs_read_full_ops;
|
|
|
|
static struct kmem_cache *nfs_rdata_cachep;
|
|
static mempool_t *nfs_rdata_mempool;
|
|
|
|
#define MIN_POOL_READ (32)
|
|
|
|
struct nfs_read_data *nfs_readdata_alloc(unsigned int pagecount)
|
|
{
|
|
struct nfs_read_data *p = mempool_alloc(nfs_rdata_mempool, GFP_NOFS);
|
|
|
|
if (p) {
|
|
memset(p, 0, sizeof(*p));
|
|
INIT_LIST_HEAD(&p->pages);
|
|
p->npages = pagecount;
|
|
p->res.seq_res.sr_slotid = NFS4_MAX_SLOT_TABLE;
|
|
if (pagecount <= ARRAY_SIZE(p->page_array))
|
|
p->pagevec = p->page_array;
|
|
else {
|
|
p->pagevec = kcalloc(pagecount, sizeof(struct page *), GFP_NOFS);
|
|
if (!p->pagevec) {
|
|
mempool_free(p, nfs_rdata_mempool);
|
|
p = NULL;
|
|
}
|
|
}
|
|
}
|
|
return p;
|
|
}
|
|
|
|
void nfs_readdata_free(struct nfs_read_data *p)
|
|
{
|
|
if (p && (p->pagevec != &p->page_array[0]))
|
|
kfree(p->pagevec);
|
|
mempool_free(p, nfs_rdata_mempool);
|
|
}
|
|
|
|
static void nfs_readdata_release(struct nfs_read_data *rdata)
|
|
{
|
|
put_nfs_open_context(rdata->args.context);
|
|
nfs_readdata_free(rdata);
|
|
}
|
|
|
|
static
|
|
int nfs_return_empty_page(struct page *page)
|
|
{
|
|
zero_user(page, 0, PAGE_CACHE_SIZE);
|
|
SetPageUptodate(page);
|
|
unlock_page(page);
|
|
return 0;
|
|
}
|
|
|
|
static void nfs_readpage_truncate_uninitialised_page(struct nfs_read_data *data)
|
|
{
|
|
unsigned int remainder = data->args.count - data->res.count;
|
|
unsigned int base = data->args.pgbase + data->res.count;
|
|
unsigned int pglen;
|
|
struct page **pages;
|
|
|
|
if (data->res.eof == 0 || remainder == 0)
|
|
return;
|
|
/*
|
|
* Note: "remainder" can never be negative, since we check for
|
|
* this in the XDR code.
|
|
*/
|
|
pages = &data->args.pages[base >> PAGE_CACHE_SHIFT];
|
|
base &= ~PAGE_CACHE_MASK;
|
|
pglen = PAGE_CACHE_SIZE - base;
|
|
for (;;) {
|
|
if (remainder <= pglen) {
|
|
zero_user(*pages, base, remainder);
|
|
break;
|
|
}
|
|
zero_user(*pages, base, pglen);
|
|
pages++;
|
|
remainder -= pglen;
|
|
pglen = PAGE_CACHE_SIZE;
|
|
base = 0;
|
|
}
|
|
}
|
|
|
|
int nfs_readpage_async(struct nfs_open_context *ctx, struct inode *inode,
|
|
struct page *page)
|
|
{
|
|
LIST_HEAD(one_request);
|
|
struct nfs_page *new;
|
|
unsigned int len;
|
|
|
|
len = nfs_page_length(page);
|
|
if (len == 0)
|
|
return nfs_return_empty_page(page);
|
|
new = nfs_create_request(ctx, inode, page, 0, len);
|
|
if (IS_ERR(new)) {
|
|
unlock_page(page);
|
|
return PTR_ERR(new);
|
|
}
|
|
if (len < PAGE_CACHE_SIZE)
|
|
zero_user_segment(page, len, PAGE_CACHE_SIZE);
|
|
|
|
nfs_list_add_request(new, &one_request);
|
|
if (NFS_SERVER(inode)->rsize < PAGE_CACHE_SIZE)
|
|
nfs_pagein_multi(inode, &one_request, 1, len, 0);
|
|
else
|
|
nfs_pagein_one(inode, &one_request, 1, len, 0);
|
|
return 0;
|
|
}
|
|
|
|
static void nfs_readpage_release(struct nfs_page *req)
|
|
{
|
|
struct inode *d_inode = req->wb_context->path.dentry->d_inode;
|
|
|
|
if (PageUptodate(req->wb_page))
|
|
nfs_readpage_to_fscache(d_inode, req->wb_page, 0);
|
|
|
|
unlock_page(req->wb_page);
|
|
|
|
dprintk("NFS: read done (%s/%Ld %d@%Ld)\n",
|
|
req->wb_context->path.dentry->d_inode->i_sb->s_id,
|
|
(long long)NFS_FILEID(req->wb_context->path.dentry->d_inode),
|
|
req->wb_bytes,
|
|
(long long)req_offset(req));
|
|
nfs_clear_request(req);
|
|
nfs_release_request(req);
|
|
}
|
|
|
|
/*
|
|
* Set up the NFS read request struct
|
|
*/
|
|
static int nfs_read_rpcsetup(struct nfs_page *req, struct nfs_read_data *data,
|
|
const struct rpc_call_ops *call_ops,
|
|
unsigned int count, unsigned int offset)
|
|
{
|
|
struct inode *inode = req->wb_context->path.dentry->d_inode;
|
|
int swap_flags = IS_SWAPFILE(inode) ? NFS_RPC_SWAPFLAGS : 0;
|
|
struct rpc_task *task;
|
|
struct rpc_message msg = {
|
|
.rpc_argp = &data->args,
|
|
.rpc_resp = &data->res,
|
|
.rpc_cred = req->wb_context->cred,
|
|
};
|
|
struct rpc_task_setup task_setup_data = {
|
|
.task = &data->task,
|
|
.rpc_client = NFS_CLIENT(inode),
|
|
.rpc_message = &msg,
|
|
.callback_ops = call_ops,
|
|
.callback_data = data,
|
|
.workqueue = nfsiod_workqueue,
|
|
.flags = RPC_TASK_ASYNC | swap_flags,
|
|
};
|
|
|
|
data->req = req;
|
|
data->inode = inode;
|
|
data->cred = msg.rpc_cred;
|
|
|
|
data->args.fh = NFS_FH(inode);
|
|
data->args.offset = req_offset(req) + offset;
|
|
data->args.pgbase = req->wb_pgbase + offset;
|
|
data->args.pages = data->pagevec;
|
|
data->args.count = count;
|
|
data->args.context = get_nfs_open_context(req->wb_context);
|
|
|
|
data->res.fattr = &data->fattr;
|
|
data->res.count = count;
|
|
data->res.eof = 0;
|
|
nfs_fattr_init(&data->fattr);
|
|
|
|
/* Set up the initial task struct. */
|
|
NFS_PROTO(inode)->read_setup(data, &msg);
|
|
|
|
dprintk("NFS: %5u initiated read call (req %s/%Ld, %u bytes @ offset %Lu)\n",
|
|
data->task.tk_pid,
|
|
inode->i_sb->s_id,
|
|
(long long)NFS_FILEID(inode),
|
|
count,
|
|
(unsigned long long)data->args.offset);
|
|
|
|
task = rpc_run_task(&task_setup_data);
|
|
if (IS_ERR(task))
|
|
return PTR_ERR(task);
|
|
rpc_put_task(task);
|
|
return 0;
|
|
}
|
|
|
|
static void
|
|
nfs_async_read_error(struct list_head *head)
|
|
{
|
|
struct nfs_page *req;
|
|
|
|
while (!list_empty(head)) {
|
|
req = nfs_list_entry(head->next);
|
|
nfs_list_remove_request(req);
|
|
SetPageError(req->wb_page);
|
|
nfs_readpage_release(req);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Generate multiple requests to fill a single page.
|
|
*
|
|
* We optimize to reduce the number of read operations on the wire. If we
|
|
* detect that we're reading a page, or an area of a page, that is past the
|
|
* end of file, we do not generate NFS read operations but just clear the
|
|
* parts of the page that would have come back zero from the server anyway.
|
|
*
|
|
* We rely on the cached value of i_size to make this determination; another
|
|
* client can fill pages on the server past our cached end-of-file, but we
|
|
* won't see the new data until our attribute cache is updated. This is more
|
|
* or less conventional NFS client behavior.
|
|
*/
|
|
static int nfs_pagein_multi(struct inode *inode, struct list_head *head, unsigned int npages, size_t count, int flags)
|
|
{
|
|
struct nfs_page *req = nfs_list_entry(head->next);
|
|
struct page *page = req->wb_page;
|
|
struct nfs_read_data *data;
|
|
size_t rsize = NFS_SERVER(inode)->rsize, nbytes;
|
|
unsigned int offset;
|
|
int requests = 0;
|
|
int ret = 0;
|
|
LIST_HEAD(list);
|
|
|
|
nfs_list_remove_request(req);
|
|
|
|
nbytes = count;
|
|
do {
|
|
size_t len = min(nbytes,rsize);
|
|
|
|
data = nfs_readdata_alloc(1);
|
|
if (!data)
|
|
goto out_bad;
|
|
list_add(&data->pages, &list);
|
|
requests++;
|
|
nbytes -= len;
|
|
} while(nbytes != 0);
|
|
atomic_set(&req->wb_complete, requests);
|
|
|
|
ClearPageError(page);
|
|
offset = 0;
|
|
nbytes = count;
|
|
do {
|
|
int ret2;
|
|
|
|
data = list_entry(list.next, struct nfs_read_data, pages);
|
|
list_del_init(&data->pages);
|
|
|
|
data->pagevec[0] = page;
|
|
|
|
if (nbytes < rsize)
|
|
rsize = nbytes;
|
|
ret2 = nfs_read_rpcsetup(req, data, &nfs_read_partial_ops,
|
|
rsize, offset);
|
|
if (ret == 0)
|
|
ret = ret2;
|
|
offset += rsize;
|
|
nbytes -= rsize;
|
|
} while (nbytes != 0);
|
|
|
|
return ret;
|
|
|
|
out_bad:
|
|
while (!list_empty(&list)) {
|
|
data = list_entry(list.next, struct nfs_read_data, pages);
|
|
list_del(&data->pages);
|
|
nfs_readdata_free(data);
|
|
}
|
|
SetPageError(page);
|
|
nfs_readpage_release(req);
|
|
return -ENOMEM;
|
|
}
|
|
|
|
static int nfs_pagein_one(struct inode *inode, struct list_head *head, unsigned int npages, size_t count, int flags)
|
|
{
|
|
struct nfs_page *req;
|
|
struct page **pages;
|
|
struct nfs_read_data *data;
|
|
int ret = -ENOMEM;
|
|
|
|
data = nfs_readdata_alloc(npages);
|
|
if (!data)
|
|
goto out_bad;
|
|
|
|
pages = data->pagevec;
|
|
while (!list_empty(head)) {
|
|
req = nfs_list_entry(head->next);
|
|
nfs_list_remove_request(req);
|
|
nfs_list_add_request(req, &data->pages);
|
|
ClearPageError(req->wb_page);
|
|
*pages++ = req->wb_page;
|
|
}
|
|
req = nfs_list_entry(data->pages.next);
|
|
|
|
return nfs_read_rpcsetup(req, data, &nfs_read_full_ops, count, 0);
|
|
out_bad:
|
|
nfs_async_read_error(head);
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* This is the callback from RPC telling us whether a reply was
|
|
* received or some error occurred (timeout or socket shutdown).
|
|
*/
|
|
int nfs_readpage_result(struct rpc_task *task, struct nfs_read_data *data)
|
|
{
|
|
int status;
|
|
|
|
dprintk("NFS: %s: %5u, (status %d)\n", __func__, task->tk_pid,
|
|
task->tk_status);
|
|
|
|
status = NFS_PROTO(data->inode)->read_done(task, data);
|
|
if (status != 0)
|
|
return status;
|
|
|
|
nfs_add_stats(data->inode, NFSIOS_SERVERREADBYTES, data->res.count);
|
|
|
|
if (task->tk_status == -ESTALE) {
|
|
set_bit(NFS_INO_STALE, &NFS_I(data->inode)->flags);
|
|
nfs_mark_for_revalidate(data->inode);
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
static void nfs_readpage_retry(struct rpc_task *task, struct nfs_read_data *data)
|
|
{
|
|
struct nfs_readargs *argp = &data->args;
|
|
struct nfs_readres *resp = &data->res;
|
|
|
|
if (resp->eof || resp->count == argp->count)
|
|
goto out;
|
|
|
|
/* This is a short read! */
|
|
nfs_inc_stats(data->inode, NFSIOS_SHORTREAD);
|
|
/* Has the server at least made some progress? */
|
|
if (resp->count == 0)
|
|
goto out;
|
|
|
|
/* Yes, so retry the read at the end of the data */
|
|
argp->offset += resp->count;
|
|
argp->pgbase += resp->count;
|
|
argp->count -= resp->count;
|
|
nfs4_restart_rpc(task, NFS_SERVER(data->inode)->nfs_client);
|
|
return;
|
|
out:
|
|
nfs4_sequence_free_slot(NFS_SERVER(data->inode)->nfs_client,
|
|
&data->res.seq_res);
|
|
return;
|
|
|
|
}
|
|
|
|
/*
|
|
* Handle a read reply that fills part of a page.
|
|
*/
|
|
static void nfs_readpage_result_partial(struct rpc_task *task, void *calldata)
|
|
{
|
|
struct nfs_read_data *data = calldata;
|
|
|
|
if (nfs_readpage_result(task, data) != 0)
|
|
return;
|
|
if (task->tk_status < 0)
|
|
return;
|
|
|
|
nfs_readpage_truncate_uninitialised_page(data);
|
|
nfs_readpage_retry(task, data);
|
|
}
|
|
|
|
static void nfs_readpage_release_partial(void *calldata)
|
|
{
|
|
struct nfs_read_data *data = calldata;
|
|
struct nfs_page *req = data->req;
|
|
struct page *page = req->wb_page;
|
|
int status = data->task.tk_status;
|
|
|
|
if (status < 0)
|
|
SetPageError(page);
|
|
|
|
if (atomic_dec_and_test(&req->wb_complete)) {
|
|
if (!PageError(page))
|
|
SetPageUptodate(page);
|
|
nfs_readpage_release(req);
|
|
}
|
|
nfs_readdata_release(calldata);
|
|
}
|
|
|
|
#if defined(CONFIG_NFS_V4_1)
|
|
void nfs_read_prepare(struct rpc_task *task, void *calldata)
|
|
{
|
|
struct nfs_read_data *data = calldata;
|
|
|
|
if (nfs4_setup_sequence(NFS_SERVER(data->inode)->nfs_client,
|
|
&data->args.seq_args, &data->res.seq_res,
|
|
0, task))
|
|
return;
|
|
rpc_call_start(task);
|
|
}
|
|
#endif /* CONFIG_NFS_V4_1 */
|
|
|
|
static const struct rpc_call_ops nfs_read_partial_ops = {
|
|
#if defined(CONFIG_NFS_V4_1)
|
|
.rpc_call_prepare = nfs_read_prepare,
|
|
#endif /* CONFIG_NFS_V4_1 */
|
|
.rpc_call_done = nfs_readpage_result_partial,
|
|
.rpc_release = nfs_readpage_release_partial,
|
|
};
|
|
|
|
static void nfs_readpage_set_pages_uptodate(struct nfs_read_data *data)
|
|
{
|
|
unsigned int count = data->res.count;
|
|
unsigned int base = data->args.pgbase;
|
|
struct page **pages;
|
|
|
|
if (data->res.eof)
|
|
count = data->args.count;
|
|
if (unlikely(count == 0))
|
|
return;
|
|
pages = &data->args.pages[base >> PAGE_CACHE_SHIFT];
|
|
base &= ~PAGE_CACHE_MASK;
|
|
count += base;
|
|
for (;count >= PAGE_CACHE_SIZE; count -= PAGE_CACHE_SIZE, pages++)
|
|
SetPageUptodate(*pages);
|
|
if (count == 0)
|
|
return;
|
|
/* Was this a short read? */
|
|
if (data->res.eof || data->res.count == data->args.count)
|
|
SetPageUptodate(*pages);
|
|
}
|
|
|
|
/*
|
|
* This is the callback from RPC telling us whether a reply was
|
|
* received or some error occurred (timeout or socket shutdown).
|
|
*/
|
|
static void nfs_readpage_result_full(struct rpc_task *task, void *calldata)
|
|
{
|
|
struct nfs_read_data *data = calldata;
|
|
|
|
if (nfs_readpage_result(task, data) != 0)
|
|
return;
|
|
if (task->tk_status < 0)
|
|
return;
|
|
/*
|
|
* Note: nfs_readpage_retry may change the values of
|
|
* data->args. In the multi-page case, we therefore need
|
|
* to ensure that we call nfs_readpage_set_pages_uptodate()
|
|
* first.
|
|
*/
|
|
nfs_readpage_truncate_uninitialised_page(data);
|
|
nfs_readpage_set_pages_uptodate(data);
|
|
nfs_readpage_retry(task, data);
|
|
}
|
|
|
|
static void nfs_readpage_release_full(void *calldata)
|
|
{
|
|
struct nfs_read_data *data = calldata;
|
|
|
|
while (!list_empty(&data->pages)) {
|
|
struct nfs_page *req = nfs_list_entry(data->pages.next);
|
|
|
|
nfs_list_remove_request(req);
|
|
nfs_readpage_release(req);
|
|
}
|
|
nfs_readdata_release(calldata);
|
|
}
|
|
|
|
static const struct rpc_call_ops nfs_read_full_ops = {
|
|
#if defined(CONFIG_NFS_V4_1)
|
|
.rpc_call_prepare = nfs_read_prepare,
|
|
#endif /* CONFIG_NFS_V4_1 */
|
|
.rpc_call_done = nfs_readpage_result_full,
|
|
.rpc_release = nfs_readpage_release_full,
|
|
};
|
|
|
|
/*
|
|
* 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_readpage(struct file *file, struct page *page)
|
|
{
|
|
struct nfs_open_context *ctx;
|
|
struct inode *inode = page->mapping->host;
|
|
int error;
|
|
|
|
dprintk("NFS: nfs_readpage (%p %ld@%lu)\n",
|
|
page, PAGE_CACHE_SIZE, page->index);
|
|
nfs_inc_stats(inode, NFSIOS_VFSREADPAGE);
|
|
nfs_add_stats(inode, NFSIOS_READPAGES, 1);
|
|
|
|
/*
|
|
* Try to flush any pending writes to the file..
|
|
*
|
|
* NOTE! Because we own the page lock, there cannot
|
|
* be any new pending writes generated at this point
|
|
* for this page (other pages can be written to).
|
|
*/
|
|
error = nfs_wb_page(inode, page);
|
|
if (error)
|
|
goto out_unlock;
|
|
if (PageUptodate(page))
|
|
goto out_unlock;
|
|
|
|
error = -ESTALE;
|
|
if (NFS_STALE(inode))
|
|
goto out_unlock;
|
|
|
|
if (file == NULL) {
|
|
error = -EBADF;
|
|
ctx = nfs_find_open_context(inode, NULL, FMODE_READ);
|
|
if (ctx == NULL)
|
|
goto out_unlock;
|
|
} else
|
|
ctx = get_nfs_open_context(nfs_file_open_context(file));
|
|
|
|
if (!IS_SYNC(inode)) {
|
|
error = nfs_readpage_from_fscache(ctx, inode, page);
|
|
if (error == 0)
|
|
goto out;
|
|
}
|
|
|
|
error = nfs_readpage_async(ctx, inode, page);
|
|
|
|
out:
|
|
put_nfs_open_context(ctx);
|
|
return error;
|
|
out_unlock:
|
|
unlock_page(page);
|
|
return error;
|
|
}
|
|
|
|
struct nfs_readdesc {
|
|
struct nfs_pageio_descriptor *pgio;
|
|
struct nfs_open_context *ctx;
|
|
};
|
|
|
|
static int
|
|
readpage_async_filler(void *data, struct page *page)
|
|
{
|
|
struct nfs_readdesc *desc = (struct nfs_readdesc *)data;
|
|
struct inode *inode = page->mapping->host;
|
|
struct nfs_page *new;
|
|
unsigned int len;
|
|
int error;
|
|
|
|
len = nfs_page_length(page);
|
|
if (len == 0)
|
|
return nfs_return_empty_page(page);
|
|
|
|
new = nfs_create_request(desc->ctx, inode, page, 0, len);
|
|
if (IS_ERR(new))
|
|
goto out_error;
|
|
|
|
if (len < PAGE_CACHE_SIZE)
|
|
zero_user_segment(page, len, PAGE_CACHE_SIZE);
|
|
if (!nfs_pageio_add_request(desc->pgio, new)) {
|
|
error = desc->pgio->pg_error;
|
|
goto out_unlock;
|
|
}
|
|
return 0;
|
|
out_error:
|
|
error = PTR_ERR(new);
|
|
SetPageError(page);
|
|
out_unlock:
|
|
unlock_page(page);
|
|
return error;
|
|
}
|
|
|
|
int nfs_readpages(struct file *filp, struct address_space *mapping,
|
|
struct list_head *pages, unsigned nr_pages)
|
|
{
|
|
struct nfs_pageio_descriptor pgio;
|
|
struct nfs_readdesc desc = {
|
|
.pgio = &pgio,
|
|
};
|
|
struct inode *inode = mapping->host;
|
|
struct nfs_server *server = NFS_SERVER(inode);
|
|
size_t rsize = server->rsize;
|
|
unsigned long npages;
|
|
int ret = -ESTALE;
|
|
|
|
dprintk("NFS: nfs_readpages (%s/%Ld %d)\n",
|
|
inode->i_sb->s_id,
|
|
(long long)NFS_FILEID(inode),
|
|
nr_pages);
|
|
nfs_inc_stats(inode, NFSIOS_VFSREADPAGES);
|
|
|
|
if (NFS_STALE(inode))
|
|
goto out;
|
|
|
|
if (filp == NULL) {
|
|
desc.ctx = nfs_find_open_context(inode, NULL, FMODE_READ);
|
|
if (desc.ctx == NULL)
|
|
return -EBADF;
|
|
} else
|
|
desc.ctx = get_nfs_open_context(nfs_file_open_context(filp));
|
|
|
|
/* attempt to read as many of the pages as possible from the cache
|
|
* - this returns -ENOBUFS immediately if the cookie is negative
|
|
*/
|
|
ret = nfs_readpages_from_fscache(desc.ctx, inode, mapping,
|
|
pages, &nr_pages);
|
|
if (ret == 0)
|
|
goto read_complete; /* all pages were read */
|
|
|
|
if (rsize < PAGE_CACHE_SIZE)
|
|
nfs_pageio_init(&pgio, inode, nfs_pagein_multi, rsize, 0);
|
|
else
|
|
nfs_pageio_init(&pgio, inode, nfs_pagein_one, rsize, 0);
|
|
|
|
ret = read_cache_pages(mapping, pages, readpage_async_filler, &desc);
|
|
|
|
nfs_pageio_complete(&pgio);
|
|
npages = (pgio.pg_bytes_written + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
|
|
nfs_add_stats(inode, NFSIOS_READPAGES, npages);
|
|
read_complete:
|
|
put_nfs_open_context(desc.ctx);
|
|
out:
|
|
return ret;
|
|
}
|
|
|
|
int __init nfs_init_readpagecache(void)
|
|
{
|
|
nfs_rdata_cachep = kmem_cache_create("nfs_read_data",
|
|
sizeof(struct nfs_read_data),
|
|
0, SLAB_HWCACHE_ALIGN,
|
|
NULL);
|
|
if (nfs_rdata_cachep == NULL)
|
|
return -ENOMEM;
|
|
|
|
nfs_rdata_mempool = mempool_create_slab_pool(MIN_POOL_READ,
|
|
nfs_rdata_cachep);
|
|
if (nfs_rdata_mempool == NULL)
|
|
return -ENOMEM;
|
|
|
|
return 0;
|
|
}
|
|
|
|
void nfs_destroy_readpagecache(void)
|
|
{
|
|
mempool_destroy(nfs_rdata_mempool);
|
|
kmem_cache_destroy(nfs_rdata_cachep);
|
|
}
|