// SPDX-License-Identifier: GPL-2.0-only
/*
* linux/fs/nfs/pagelist.c
*
* A set of helper functions for managing NFS read and write requests.
* The main purpose of these routines is to provide support for the
* coalescing of several requests into a single RPC call.
*
* Copyright 2000, 2001 (c) Trond Myklebust <[email protected]>
*
*/
#include <linux/slab.h>
#include <linux/file.h>
#include <linux/sched.h>
#include <linux/sunrpc/clnt.h>
#include <linux/nfs.h>
#include <linux/nfs3.h>
#include <linux/nfs4.h>
#include <linux/nfs_fs.h>
#include <linux/nfs_page.h>
#include <linux/nfs_mount.h>
#include <linux/export.h>
#include <linux/filelock.h>
#include "internal.h"
#include "pnfs.h"
#include "nfstrace.h"
#include "fscache.h"
#define NFSDBG_FACILITY NFSDBG_PAGECACHE
static struct kmem_cache *nfs_page_cachep;
static const struct rpc_call_ops nfs_pgio_common_ops;
struct nfs_page_iter_page {
const struct nfs_page *req;
size_t count;
};
static void nfs_page_iter_page_init(struct nfs_page_iter_page *i,
const struct nfs_page *req)
{
i->req = req;
i->count = 0;
}
static void nfs_page_iter_page_advance(struct nfs_page_iter_page *i, size_t sz)
{
const struct nfs_page *req = i->req;
size_t tmp = i->count + sz;
i->count = (tmp < req->wb_bytes) ? tmp : req->wb_bytes;
}
static struct page *nfs_page_iter_page_get(struct nfs_page_iter_page *i)
{
const struct nfs_page *req = i->req;
struct page *page;
if (i->count != req->wb_bytes) {
size_t base = i->count + req->wb_pgbase;
size_t len = PAGE_SIZE - offset_in_page(base);
page = nfs_page_to_page(req, base);
nfs_page_iter_page_advance(i, len);
return page;
}
return NULL;
}
static struct nfs_pgio_mirror *
nfs_pgio_get_mirror(struct nfs_pageio_descriptor *desc, u32 idx)
{
if (desc->pg_ops->pg_get_mirror)
return desc->pg_ops->pg_get_mirror(desc, idx);
return &desc->pg_mirrors[0];
}
struct nfs_pgio_mirror *
nfs_pgio_current_mirror(struct nfs_pageio_descriptor *desc)
{
return nfs_pgio_get_mirror(desc, desc->pg_mirror_idx);
}
EXPORT_SYMBOL_GPL(nfs_pgio_current_mirror);
static u32
nfs_pgio_set_current_mirror(struct nfs_pageio_descriptor *desc, u32 idx)
{
if (desc->pg_ops->pg_set_mirror)
return desc->pg_ops->pg_set_mirror(desc, idx);
return desc->pg_mirror_idx;
}
void nfs_pgheader_init(struct nfs_pageio_descriptor *desc,
struct nfs_pgio_header *hdr,
void (*release)(struct nfs_pgio_header *hdr))
{
struct nfs_pgio_mirror *mirror = nfs_pgio_current_mirror(desc);
hdr->req = nfs_list_entry(mirror->pg_list.next);
hdr->inode = desc->pg_inode;
hdr->cred = nfs_req_openctx(hdr->req)->cred;
hdr->io_start = req_offset(hdr->req);
hdr->good_bytes = mirror->pg_count;
hdr->io_completion = desc->pg_io_completion;
hdr->dreq = desc->pg_dreq;
nfs_netfs_set_pgio_header(hdr, desc);
hdr->release = release;
hdr->completion_ops = desc->pg_completion_ops;
if (hdr->completion_ops->init_hdr)
hdr->completion_ops->init_hdr(hdr);
hdr->pgio_mirror_idx = desc->pg_mirror_idx;
}
EXPORT_SYMBOL_GPL(nfs_pgheader_init);
void nfs_set_pgio_error(struct nfs_pgio_header *hdr, int error, loff_t pos)
{
unsigned int new = pos - hdr->io_start;
trace_nfs_pgio_error(hdr, error, pos);
if (hdr->good_bytes > new) {
hdr->good_bytes = new;
clear_bit(NFS_IOHDR_EOF, &hdr->flags);
if (!test_and_set_bit(NFS_IOHDR_ERROR, &hdr->flags))
hdr->error = error;
}
}
static inline struct nfs_page *nfs_page_alloc(void)
{
struct nfs_page *p =
kmem_cache_zalloc(nfs_page_cachep, nfs_io_gfp_mask());
if (p)
INIT_LIST_HEAD(&p->wb_list);
return p;
}
static inline void
nfs_page_free(struct nfs_page *p)
{
kmem_cache_free(nfs_page_cachep, p);
}
/**
* nfs_iocounter_wait - wait for i/o to complete
* @l_ctx: nfs_lock_context with io_counter to use
*
* returns -ERESTARTSYS if interrupted by a fatal signal.
* Otherwise returns 0 once the io_count hits 0.
*/
int
nfs_iocounter_wait(struct nfs_lock_context *l_ctx)
{
return wait_var_event_killable(&l_ctx->io_count,
!atomic_read(&l_ctx->io_count));
}
/**
* nfs_async_iocounter_wait - wait on a rpc_waitqueue for I/O
* to complete
* @task: the rpc_task that should wait
* @l_ctx: nfs_lock_context with io_counter to check
*
* Returns true if there is outstanding I/O to wait on and the
* task has been put to sleep.
*/
bool
nfs_async_iocounter_wait(struct rpc_task *task, struct nfs_lock_context *l_ctx)
{
struct inode *inode = d_inode(l_ctx->open_context->dentry);
bool ret = false;
if (atomic_read(&l_ctx->io_count) > 0) {
rpc_sleep_on(&NFS_SERVER(inode)->uoc_rpcwaitq, task, NULL);
ret = true;
}
if (atomic_read(&l_ctx->io_count) == 0) {
rpc_wake_up_queued_task(&NFS_SERVER(inode)->uoc_rpcwaitq, task);
ret = false;
}
return ret;
}
EXPORT_SYMBOL_GPL(nfs_async_iocounter_wait);
/*
* nfs_page_set_headlock - set the request PG_HEADLOCK
* @req: request that is to be locked
*
* this lock must be held when modifying req->wb_head
*
* return 0 on success, < 0 on error
*/
int
nfs_page_set_headlock(struct nfs_page *req)
{
if (!test_and_set_bit(PG_HEADLOCK, &req->wb_flags))
return 0;
set_bit(PG_CONTENDED1, &req->wb_flags);
smp_mb__after_atomic();
return wait_on_bit_lock(&req->wb_flags, PG_HEADLOCK,
TASK_UNINTERRUPTIBLE);
}
/*
* nfs_page_clear_headlock - clear the request PG_HEADLOCK
* @req: request that is to be locked
*/
void
nfs_page_clear_headlock(struct nfs_page *req)
{
clear_bit_unlock(PG_HEADLOCK, &req->wb_flags);
smp_mb__after_atomic();
if (!test_bit(PG_CONTENDED1, &req->wb_flags))
return;
wake_up_bit(&req->wb_flags, PG_HEADLOCK);
}
/*
* nfs_page_group_lock - lock the head of the page group
* @req: request in group that is to be locked
*
* this lock must be held when traversing or modifying the page
* group list
*
* return 0 on success, < 0 on error
*/
int
nfs_page_group_lock(struct nfs_page *req)
{
int ret;
ret = nfs_page_set_headlock(req);
if (ret || req->wb_head == req)
return ret;
return nfs_page_set_headlock(req->wb_head);
}
/*
* nfs_page_group_unlock - unlock the head of the page group
* @req: request in group that is to be unlocked
*/
void
nfs_page_group_unlock(struct nfs_page *req)
{
if (req != req->wb_head)
nfs_page_clear_headlock(req->wb_head);
nfs_page_clear_headlock(req);
}
/*
* nfs_page_group_sync_on_bit_locked
*
* must be called with page group lock held
*/
static bool
nfs_page_group_sync_on_bit_locked(struct nfs_page *req, unsigned int bit)
{
struct nfs_page *head = req->wb_head;
struct nfs_page *tmp;
WARN_ON_ONCE(!test_bit(PG_HEADLOCK, &head->wb_flags));
WARN_ON_ONCE(test_and_set_bit(bit, &req->wb_flags));
tmp = req->wb_this_page;
while (tmp != req) {
if (!test_bit(bit, &tmp->wb_flags))
return false;
tmp = tmp->wb_this_page;
}
/* true! reset all bits */
tmp = req;
do {
clear_bit(bit, &tmp->wb_flags);
tmp = tmp->wb_this_page;
} while (tmp != req);
return true;
}
/*
* nfs_page_group_sync_on_bit - set bit on current request, but only
* return true if the bit is set for all requests in page group
* @req - request in page group
* @bit - PG_* bit that is used to sync page group
*/
bool nfs_page_group_sync_on_bit(struct nfs_page *req, unsigned int bit)
{
bool ret;
nfs_page_group_lock(req);
ret = nfs_page_group_sync_on_bit_locked(req, bit);
nfs_page_group_unlock(req);
return ret;
}
/*
* nfs_page_group_init - Initialize the page group linkage for @req
* @req - a new nfs request
* @prev - the previous request in page group, or NULL if @req is the first
* or only request in the group (the head).
*/
static inline void
nfs_page_group_init(struct nfs_page *req, struct nfs_page *prev)
{
struct inode *inode;
WARN_ON_ONCE(prev == req);
if (!prev) {
/* a head request */
req->wb_head = req;
req->wb_this_page = req;
} else {
/* a subrequest */
WARN_ON_ONCE(prev->wb_this_page != prev->wb_head);
WARN_ON_ONCE(!test_bit(PG_HEADLOCK, &prev->wb_head->wb_flags));
req->wb_head = prev->wb_head;
req->wb_this_page = prev->wb_this_page;
prev->wb_this_page = req;
/* All subrequests take a ref on the head request until
* nfs_page_group_destroy is called */
kref_get(&req->wb_head->wb_kref);
/* grab extra ref and bump the request count if head request
* has extra ref from the write/commit path to handle handoff
* between write and commit lists. */
if (test_bit(PG_INODE_REF, &prev->wb_head->wb_flags)) {
inode = nfs_page_to_inode(req);
set_bit(PG_INODE_REF, &req->wb_flags);
kref_get(&req->wb_kref);
atomic_long_inc(&NFS_I(inode)->nrequests);
}
}
}
/*
* nfs_page_group_destroy - sync the destruction of page groups
* @req - request that no longer needs the page group
*
* releases the page group reference from each member once all
* members have called this function.
*/
static void
nfs_page_group_destroy(struct kref *kref)
{
struct nfs_page *req = container_of(kref, struct nfs_page, wb_kref);
struct nfs_page *head = req->wb_head;
struct nfs_page *tmp, *next;
if (!nfs_page_group_sync_on_bit(req, PG_TEARDOWN))
goto out;
tmp = req;
do {
next = tmp->wb_this_page;
/* unlink and free */
tmp->wb_this_page = tmp;
tmp->wb_head = tmp;
nfs_free_request(tmp);
tmp = next;
} while (tmp != req);
out:
/* subrequests must release the ref on the head request */
if (head != req)
nfs_release_request(head);
}
static struct nfs_page *nfs_page_create(struct nfs_lock_context *l_ctx,
unsigned int pgbase, pgoff_t index,
unsigned int offset, unsigned int count)
{
struct nfs_page *req;
struct nfs_open_context *ctx = l_ctx->open_context;
if (test_bit(NFS_CONTEXT_BAD, &ctx->flags))
return ERR_PTR(-EBADF);
/* try to allocate the request struct */
req = nfs_page_alloc();
if (req == NULL)
return ERR_PTR(-ENOMEM);
req->wb_lock_context = l_ctx;
refcount_inc(&l_ctx->count);
atomic_inc(&l_ctx->io_count);
/* Initialize the request struct. Initially, we assume a
* long write-back delay. This will be adjusted in
* update_nfs_request below if the region is not locked. */
req->wb_pgbase = pgbase;
req->wb_index = index;
req->wb_offset = offset;
req->wb_bytes = count;
kref_init(&req->wb_kref);
req->wb_nio = 0;
return req;
}
static void nfs_page_assign_folio(struct nfs_page *req, struct folio *folio)
{
if (folio != NULL) {
req->wb_folio = folio;
folio_get(folio);
set_bit(PG_FOLIO, &req->wb_flags);
}
}
static void nfs_page_assign_page(struct nfs_page *req, struct page *page)
{
if (page != NULL) {
req->wb_page = page;
get_page(page);
}
}
/**
* nfs_page_create_from_page - Create an NFS read/write request.
* @ctx: open context to use
* @page: page to write
* @pgbase: starting offset within the page for the write
* @offset: file offset for the write
* @count: number of bytes to read/write
*
* The page must be locked by the caller. This makes sure we never
* create two different requests for the same page.
* User should ensure it is safe to sleep in this function.
*/
struct nfs_page *nfs_page_create_from_page(struct nfs_open_context *ctx,
struct page *page,
unsigned int pgbase, loff_t offset,
unsigned int count)
{
struct nfs_lock_context *l_ctx = nfs_get_lock_context(ctx);
struct nfs_page *ret;
if (IS_ERR(l_ctx))
return ERR_CAST(l_ctx);
ret = nfs_page_create(l_ctx, pgbase, offset >> PAGE_SHIFT,
offset_in_page(offset), count);
if (!IS_ERR(ret)) {
nfs_page_assign_page(ret, page);
nfs_page_group_init(ret, NULL);
}
nfs_put_lock_context(l_ctx);
return ret;
}
/**
* nfs_page_create_from_folio - Create an NFS read/write request.
* @ctx: open context to use
* @folio: folio to write
* @offset: starting offset within the folio for the write
* @count: number of bytes to read/write
*
* The page must be locked by the caller. This makes sure we never
* create two different requests for the same page.
* User should ensure it is safe to sleep in this function.
*/
struct nfs_page *nfs_page_create_from_folio(struct nfs_open_context *ctx,
struct folio *folio,
unsigned int offset,
unsigned int count)
{
struct nfs_lock_context *l_ctx = nfs_get_lock_context(ctx);
struct nfs_page *ret;
if (IS_ERR(l_ctx))
return ERR_CAST(l_ctx);
ret = nfs_page_create(l_ctx, offset, folio->index, offset, count);
if (!IS_ERR(ret)) {
nfs_page_assign_folio(ret, folio);
nfs_page_group_init(ret, NULL);
}
nfs_put_lock_context(l_ctx);
return ret;
}
static struct nfs_page *
nfs_create_subreq(struct nfs_page *req,
unsigned int pgbase,
unsigned int offset,
unsigned int count)
{
struct nfs_page *last;
struct nfs_page *ret;
struct folio *folio = nfs_page_to_folio(req);
struct page *page = nfs_page_to_page(req, pgbase);
ret = nfs_page_create(req->wb_lock_context, pgbase, req->wb_index,
offset, count);
if (!IS_ERR(ret)) {
if (folio)
nfs_page_assign_folio(ret, folio);
else
nfs_page_assign_page(ret, page);
/* find the last request */
for (last = req->wb_head;
last->wb_this_page != req->wb_head;
last = last->wb_this_page)
;
nfs_lock_request(ret);
nfs_page_group_init(ret, last);
ret->wb_nio = req->wb_nio;
}
return ret;
}
/**
* nfs_unlock_request - Unlock request and wake up sleepers.
* @req: pointer to request
*/
void nfs_unlock_request(struct nfs_page *req)
{
clear_bit_unlock(PG_BUSY, &req->wb_flags);
smp_mb__after_atomic();
if (!test_bit(PG_CONTENDED2, &req->wb_flags))
return;
wake_up_bit(&req->wb_flags, PG_BUSY);
}
/**
* nfs_unlock_and_release_request - Unlock request and release the nfs_page
* @req: pointer to request
*/
void nfs_unlock_and_release_request(struct nfs_page *req)
{
nfs_unlock_request(req);
nfs_release_request(req);
}
/*
* nfs_clear_request - Free up all resources allocated to the request
* @req:
*
* Release page and open context resources associated with a read/write
* request after it has completed.
*/
static void nfs_clear_request(struct nfs_page *req)
{
struct folio *folio = nfs_page_to_folio(req);
struct page *page = req->wb_page;
struct nfs_lock_context *l_ctx = req->wb_lock_context;
struct nfs_open_context *ctx;
if (folio != NULL) {
folio_put(folio);
req->wb_folio = NULL;
clear_bit(PG_FOLIO, &req->wb_flags);
} else if (page != NULL) {
put_page(page);
req->wb_page = NULL;
}
if (l_ctx != NULL) {
if (atomic_dec_and_test(&l_ctx->io_count)) {
wake_up_var(&l_ctx->io_count);
ctx = l_ctx->open_context;
if (test_bit(NFS_CONTEXT_UNLOCK, &ctx->flags))
rpc_wake_up(&NFS_SERVER(d_inode(ctx->dentry))->uoc_rpcwaitq);
}
nfs_put_lock_context(l_ctx);
req->wb_lock_context = NULL;
}
}
/**
* nfs_free_request - Release the count on an NFS read/write request
* @req: request to release
*
* Note: Should never be called with the spinlock held!
*/
void nfs_free_request(struct nfs_page *req)
{
WARN_ON_ONCE(req->wb_this_page != req);
/* extra debug: make sure no sync bits are still set */
WARN_ON_ONCE(test_bit(PG_TEARDOWN, &req->wb_flags));
WARN_ON_ONCE(test_bit(PG_UNLOCKPAGE, &req->wb_flags));
WARN_ON_ONCE(test_bit(PG_UPTODATE, &req->wb_flags));
WARN_ON_ONCE(test_bit(PG_WB_END, &req->wb_flags));
WARN_ON_ONCE(test_bit(PG_REMOVE, &req->wb_flags));
/* Release struct file and open context */
nfs_clear_request(req);
nfs_page_free(req);
}
void nfs_release_request(struct nfs_page *req)
{
kref_put(&req->wb_kref, nfs_page_group_destroy);
}
EXPORT_SYMBOL_GPL(nfs_release_request);
/*
* nfs_generic_pg_test - determine if requests can be coalesced
* @desc: pointer to descriptor
* @prev: previous request in desc, or NULL
* @req: this request
*
* Returns zero if @req cannot be coalesced into @desc, otherwise it returns
* the size of the request.
*/
size_t nfs_generic_pg_test(struct nfs_pageio_descriptor *desc,
struct nfs_page *prev, struct nfs_page *req)
{
struct nfs_pgio_mirror *mirror = nfs_pgio_current_mirror(desc);
if (mirror->pg_count > mirror->pg_bsize) {
/* should never happen */
WARN_ON_ONCE(1);
return 0;
}
/*
* Limit the request size so that we can still allocate a page array
* for it without upsetting the slab allocator.
*/
if (((mirror->pg_count + req->wb_bytes) >> PAGE_SHIFT) *
sizeof(struct page *) > PAGE_SIZE)
return 0;
return min(mirror->pg_bsize - mirror->pg_count, (size_t)req->wb_bytes);
}
EXPORT_SYMBOL_GPL(nfs_generic_pg_test);
struct nfs_pgio_header *nfs_pgio_header_alloc(const struct nfs_rw_ops *ops)
{
struct nfs_pgio_header *hdr = ops->rw_alloc_header();
if (hdr) {
INIT_LIST_HEAD(&hdr->pages);
hdr->rw_ops = ops;
}
return hdr;
}
EXPORT_SYMBOL_GPL(nfs_pgio_header_alloc);
/**
* nfs_pgio_data_destroy - make @hdr suitable for reuse
*
* Frees memory and releases refs from nfs_generic_pgio, so that it may
* be called again.
*
* @hdr: A header that has had nfs_generic_pgio called
*/
static void nfs_pgio_data_destroy(struct nfs_pgio_header *hdr)
{
if (hdr->args.context)
put_nfs_open_context(hdr->args.context);
if (hdr->page_array.pagevec != hdr->page_array.page_array)
kfree(hdr->page_array.pagevec);
}
/*
* nfs_pgio_header_free - Free a read or write header
* @hdr: The header to free
*/
void nfs_pgio_header_free(struct nfs_pgio_header *hdr)
{
nfs_pgio_data_destroy(hdr);
hdr->rw_ops->rw_free_header(hdr);
}
EXPORT_SYMBOL_GPL(nfs_pgio_header_free);
/**
* nfs_pgio_rpcsetup - Set up arguments for a pageio call
* @hdr: The pageio hdr
* @pgbase: base
* @count: Number of bytes to read
* @how: How to commit data (writes only)
* @cinfo: Commit information for the call (writes only)
*/
static void nfs_pgio_rpcsetup(struct nfs_pgio_header *hdr, unsigned int pgbase,
unsigned int count, int how,
struct nfs_commit_info *cinfo)
{
struct nfs_page *req = hdr->req;
/* Set up the RPC argument and reply structs
* NB: take care not to mess about with hdr->commit et al. */
hdr->args.fh = NFS_FH(hdr->inode);
hdr->args.offset = req_offset(req);
/* pnfs_set_layoutcommit needs this */
hdr->mds_offset = hdr->args.offset;
hdr->args.pgbase = pgbase;
hdr->args.pages = hdr->page_array.pagevec;
hdr->args.count = count;
hdr->args.context = get_nfs_open_context(nfs_req_openctx(req));
hdr->args.lock_context = req->wb_lock_context;
hdr->args.stable = NFS_UNSTABLE;
switch (how & (FLUSH_STABLE | FLUSH_COND_STABLE)) {
case 0:
break;
case FLUSH_COND_STABLE:
if (nfs_reqs_to_commit(cinfo))
break;
fallthrough;
default:
hdr->args.stable = NFS_FILE_SYNC;
}
hdr->res.fattr = &hdr->fattr;
hdr->res.count = 0;
hdr->res.eof = 0;
hdr->res.verf = &hdr->verf;
nfs_fattr_init(&hdr->fattr);
}
/**
* nfs_pgio_prepare - Prepare pageio hdr to go over the wire
* @task: The current task
* @calldata: pageio header to prepare
*/
static void nfs_pgio_prepare(struct rpc_task *task, void *calldata)
{
struct nfs_pgio_header *hdr = calldata;
int err;
err = NFS_PROTO(hdr->inode)->pgio_rpc_prepare(task, hdr);
if (err)
rpc_exit(task, err);
}
int nfs_initiate_pgio(struct rpc_clnt *clnt, struct nfs_pgio_header *hdr,
const struct cred *cred, const struct nfs_rpc_ops *rpc_ops,
const struct rpc_call_ops *call_ops, int how, int flags,
struct nfsd_file *localio)
{
struct rpc_task *task;
struct rpc_message msg = {
.rpc_argp = &hdr->args,
.rpc_resp = &hdr->res,
.rpc_cred = cred,
};
struct rpc_task_setup task_setup_data = {
.rpc_client = clnt,
.task = &hdr->task,
.rpc_message = &msg,
.callback_ops = call_ops,
.callback_data = hdr,
.workqueue = nfsiod_workqueue,
.flags = RPC_TASK_ASYNC | flags,
};
if (nfs_server_capable(hdr->inode, NFS_CAP_MOVEABLE))
task_setup_data.flags |= RPC_TASK_MOVEABLE;
hdr->rw_ops->rw_initiate(hdr, &msg, rpc_ops, &task_setup_data, how);
dprintk("NFS: initiated pgio call "
"(req %s/%llu, %u bytes @ offset %llu)\n",
hdr->inode->i_sb->s_id,
(unsigned long long)NFS_FILEID(hdr->inode),
hdr->args.count,
(unsigned long long)hdr->args.offset);
if (localio)
return nfs_local_doio(NFS_SERVER(hdr->inode)->nfs_client,
localio, hdr, call_ops);
task = rpc_run_task(&task_setup_data);
if (IS_ERR(task))
return PTR_ERR(task);
rpc_put_task(task);
return 0;
}
EXPORT_SYMBOL_GPL(nfs_initiate_pgio);
/**
* nfs_pgio_error - Clean up from a pageio error
* @hdr: pageio header
*/
static void nfs_pgio_error(struct nfs_pgio_header *hdr)
{
set_bit(NFS_IOHDR_REDO, &hdr->flags);
hdr->completion_ops->completion(hdr);
}
/**
* nfs_pgio_release - Release pageio data
* @calldata: The pageio header to release
*/
static void nfs_pgio_release(void *calldata)
{
struct nfs_pgio_header *hdr = calldata;
hdr->completion_ops->completion(hdr);
}
static void nfs_pageio_mirror_init(struct nfs_pgio_mirror *mirror,
unsigned int bsize)
{
INIT_LIST_HEAD(&mirror->pg_list);
mirror->pg_bytes_written = 0;
mirror->pg_count = 0;
mirror->pg_bsize = bsize;
mirror->pg_base = 0;
mirror->pg_recoalesce = 0;
}
/**
* nfs_pageio_init - initialise a page io descriptor
* @desc: pointer to descriptor
* @inode: pointer to inode
* @pg_ops: pointer to pageio operations
* @compl_ops: pointer to pageio completion operations
* @rw_ops: pointer to nfs read/write operations
* @bsize: io block size
* @io_flags: extra parameters for the io function
*/
void nfs_pageio_init(struct nfs_pageio_descriptor *desc,
struct inode *inode,
const struct nfs_pageio_ops *pg_ops,
const struct nfs_pgio_completion_ops *compl_ops,
const struct nfs_rw_ops *rw_ops,
size_t bsize,
int io_flags)
{
desc->pg_moreio = 0;
desc->pg_inode = inode;
desc->pg_ops = pg_ops;
desc->pg_completion_ops = compl_ops;
desc->pg_rw_ops = rw_ops;
desc->pg_ioflags = io_flags;
desc->pg_error = 0;
desc->pg_lseg = NULL;
desc->pg_io_completion = NULL;
desc->pg_dreq = NULL;
nfs_netfs_reset_pageio_descriptor(desc);
desc->pg_bsize = bsize;
desc->pg_mirror_count = 1;
desc->pg_mirror_idx = 0;
desc->pg_mirrors_dynamic = NULL;
desc->pg_mirrors = desc->pg_mirrors_static;
nfs_pageio_mirror_init(&desc->pg_mirrors[0], bsize);
desc->pg_maxretrans = 0;
}
/**
* nfs_pgio_result - Basic pageio error handling
* @task: The task that ran
* @calldata: Pageio header to check
*/
static void nfs_pgio_result(struct rpc_task *task, void *calldata)
{
struct nfs_pgio_header *hdr = calldata;
struct inode *inode = hdr->inode;
if (hdr->rw_ops->rw_done(task, hdr, inode) != 0)
return;
if (task->tk_status < 0)
nfs_set_pgio_error(hdr, task->tk_status, hdr->args.offset);
else
hdr->rw_ops->rw_result(task, hdr);
}
/*
* Create an RPC task for the given read or write request and kick it.
* The page must have been locked by the caller.
*
* It may happen that the page we're passed is not marked dirty.
* This is the case if nfs_updatepage detects a conflicting request
* that has been written but not committed.
*/
int nfs_generic_pgio(struct nfs_pageio_descriptor *desc,
struct nfs_pgio_header *hdr)
{
struct nfs_pgio_mirror *mirror = nfs_pgio_current_mirror(desc);
struct nfs_page *req;
struct page **pages,
*last_page;
struct list_head *head = &mirror->pg_list;
struct nfs_commit_info cinfo;
struct nfs_page_array *pg_array = &hdr->page_array;
unsigned int pagecount, pageused;
unsigned int pg_base = offset_in_page(mirror->pg_base);
gfp_t gfp_flags = nfs_io_gfp_mask();
pagecount = nfs_page_array_len(pg_base, mirror->pg_count);
pg_array->npages = pagecount;
if (pagecount <= ARRAY_SIZE(pg_array->page_array))
pg_array->pagevec = pg_array->page_array;
else {
pg_array->pagevec = kcalloc(pagecount, sizeof(struct page *), gfp_flags);
if (!pg_array->pagevec) {
pg_array->npages = 0;
nfs_pgio_error(hdr);
desc->pg_error = -ENOMEM;
return desc->pg_error;
}
}
nfs_init_cinfo(&cinfo, desc->pg_inode, desc->pg_dreq);
pages = hdr->page_array.pagevec;
last_page = NULL;
pageused = 0;
while (!list_empty(head)) {
struct nfs_page_iter_page i;
struct page *page;
req = nfs_list_entry(head->next);
nfs_list_move_request(req, &hdr->pages);
if (req->wb_pgbase == 0)
last_page = NULL;
nfs_page_iter_page_init(&i, req);
while ((page = nfs_page_iter_page_get(&i)) != NULL) {
if (last_page != page) {
pageused++;
if (pageused > pagecount)
goto full;
*pages++ = last_page = page;
}
}
}
full:
if (WARN_ON_ONCE(pageused != pagecount)) {
nfs_pgio_error(hdr);
desc->pg_error = -EINVAL;
return desc->pg_error;
}
if ((desc->pg_ioflags & FLUSH_COND_STABLE) &&
(desc->pg_moreio || nfs_reqs_to_commit(&cinfo)))
desc->pg_ioflags &= ~FLUSH_COND_STABLE;
/* Set up the argument struct */
nfs_pgio_rpcsetup(hdr, pg_base, mirror->pg_count, desc->pg_ioflags,
&cinfo);
desc->pg_rpc_callops = &nfs_pgio_common_ops;
return 0;
}
EXPORT_SYMBOL_GPL(nfs_generic_pgio);
static int nfs_generic_pg_pgios(struct nfs_pageio_descriptor *desc)
{
struct nfs_pgio_header *hdr;
int ret;
unsigned short task_flags = 0;
hdr = nfs_pgio_header_alloc(desc->pg_rw_ops);
if (!hdr) {
desc->pg_error = -ENOMEM;
return desc->pg_error;
}
nfs_pgheader_init(desc, hdr, nfs_pgio_header_free);
ret = nfs_generic_pgio(desc, hdr);
if (ret == 0) {
struct nfs_client *clp = NFS_SERVER(hdr->inode)->nfs_client;
struct nfsd_file *localio =
nfs_local_open_fh(clp, hdr->cred,
hdr->args.fh, hdr->args.context->mode);
if (NFS_SERVER(hdr->inode)->nfs_client->cl_minorversion)
task_flags = RPC_TASK_MOVEABLE;
ret = nfs_initiate_pgio(NFS_CLIENT(hdr->inode),
hdr,
hdr->cred,
NFS_PROTO(hdr->inode),
desc->pg_rpc_callops,
desc->pg_ioflags,
RPC_TASK_CRED_NOREF | task_flags,
localio);
}
return ret;
}
static struct nfs_pgio_mirror *
nfs_pageio_alloc_mirrors(struct nfs_pageio_descriptor *desc,
unsigned int mirror_count)
{
struct nfs_pgio_mirror *ret;
unsigned int i;
kfree(desc->pg_mirrors_dynamic);
desc->pg_mirrors_dynamic = NULL;
if (mirror_count == 1)
return desc->pg_mirrors_static;
ret = kmalloc_array(mirror_count, sizeof(*ret), nfs_io_gfp_mask());
if (ret != NULL) {
for (i = 0; i < mirror_count; i++)
nfs_pageio_mirror_init(&ret[i], desc->pg_bsize);
desc->pg_mirrors_dynamic = ret;
}
return ret;
}
/*
* nfs_pageio_setup_mirroring - determine if mirroring is to be used
* by calling the pg_get_mirror_count op
*/
static void nfs_pageio_setup_mirroring(struct nfs_pageio_descriptor *pgio,
struct nfs_page *req)
{
unsigned int mirror_count = 1;
if (pgio->pg_ops->pg_get_mirror_count)
mirror_count = pgio->pg_ops->pg_get_mirror_count(pgio, req);
if (mirror_count == pgio->pg_mirror_count || pgio->pg_error < 0)
return;
if (!mirror_count || mirror_count > NFS_PAGEIO_DESCRIPTOR_MIRROR_MAX) {
pgio->pg_error = -EINVAL;
return;
}
pgio->pg_mirrors = nfs_pageio_alloc_mirrors(pgio, mirror_count);
if (pgio->pg_mirrors == NULL) {
pgio->pg_error = -ENOMEM;
pgio->pg_mirrors = pgio->pg_mirrors_static;
mirror_count = 1;
}
pgio->pg_mirror_count = mirror_count;
}
static void nfs_pageio_cleanup_mirroring(struct nfs_pageio_descriptor *pgio)
{
pgio->pg_mirror_count = 1;
pgio->pg_mirror_idx = 0;
pgio->pg_mirrors = pgio->pg_mirrors_static;
kfree(pgio->pg_mirrors_dynamic);
pgio->pg_mirrors_dynamic = NULL;
}
static bool nfs_match_lock_context(const struct nfs_lock_context *l1,
const struct nfs_lock_context *l2)
{
return l1->lockowner == l2->lockowner;
}
static bool nfs_page_is_contiguous(const struct nfs_page *prev,
const struct nfs_page *req)
{
size_t prev_end = prev->wb_pgbase + prev->wb_bytes;
if (req_offset(req) != req_offset(prev) + prev->wb_bytes)
return false;
if (req->wb_pgbase == 0)
return prev_end == nfs_page_max_length(prev);
if (req->wb_pgbase == prev_end) {
struct folio *folio = nfs_page_to_folio(req);
if (folio)
return folio == nfs_page_to_folio(prev);
return req->wb_page == prev->wb_page;
}
return false;
}
/**
* nfs_coalesce_size - test two requests for compatibility
* @prev: pointer to nfs_page
* @req: pointer to nfs_page
* @pgio: pointer to nfs_pagio_descriptor
*
* The nfs_page structures 'prev' and 'req' are compared to ensure that the
* page data area they describe is contiguous, and that their RPC
* credentials, NFSv4 open state, and lockowners are the same.
*
* Returns size of the request that can be coalesced
*/
static unsigned int nfs_coalesce_size(struct nfs_page *prev,
struct nfs_page *req,
struct nfs_pageio_descriptor *pgio)
{
struct file_lock_context *flctx;
if (prev) {
if (!nfs_match_open_context(nfs_req_openctx(req), nfs_req_openctx(prev)))
return 0;
flctx = locks_inode_context(d_inode(nfs_req_openctx(req)->dentry));
if (flctx != NULL &&
!(list_empty_careful(&flctx->flc_posix) &&
list_empty_careful(&flctx->flc_flock)) &&
!nfs_match_lock_context(req->wb_lock_context,
prev->wb_lock_context))
return 0;
if (!nfs_page_is_contiguous(prev, req))
return 0;
}
return pgio->pg_ops->pg_test(pgio, prev, req);
}
/**
* nfs_pageio_do_add_request - Attempt to coalesce a request into a page list.
* @desc: destination io descriptor
* @req: request
*
* If the request 'req' was successfully coalesced into the existing list
* of pages 'desc', it returns the size of req.
*/
static unsigned int
nfs_pageio_do_add_request(struct nfs_pageio_descriptor *desc,
struct nfs_page *req)
{
struct nfs_pgio_mirror *mirror = nfs_pgio_current_mirror(desc);
struct nfs_page *prev = NULL;
unsigned int size;
if (list_empty(&mirror->pg_list)) {
if (desc->pg_ops->pg_init)
desc->pg_ops->pg_init(desc, req);
if (desc->pg_error < 0)
return 0;
mirror->pg_base = req->wb_pgbase;
mirror->pg_count = 0;
mirror->pg_recoalesce = 0;
} else
prev = nfs_list_entry(mirror->pg_list.prev);
if (desc->pg_maxretrans && req->wb_nio > desc->pg_maxretrans) {
if (NFS_SERVER(desc->pg_inode)->flags & NFS_MOUNT_SOFTERR)
desc->pg_error = -ETIMEDOUT;
else
desc->pg_error = -EIO;
return 0;
}
size = nfs_coalesce_size(prev, req, desc);
if (size < req->wb_bytes)
return size;
nfs_list_move_request(req, &mirror->pg_list);
mirror->pg_count += req->wb_bytes;
return req->wb_bytes;
}
/*
* Helper for nfs_pageio_add_request and nfs_pageio_complete
*/
static void nfs_pageio_doio(struct nfs_pageio_descriptor *desc)
{
struct nfs_pgio_mirror *mirror = nfs_pgio_current_mirror(desc);
if (!list_empty(&mirror->pg_list)) {
int error = desc->pg_ops->pg_doio(desc);
if (error < 0)
desc->pg_error = error;
if (list_empty(&mirror->pg_list))
mirror->pg_bytes_written += mirror->pg_count;
}
}
static void
nfs_pageio_cleanup_request(struct nfs_pageio_descriptor *desc,
struct nfs_page *req)
{
LIST_HEAD(head);
nfs_list_move_request(req, &head);
desc->pg_completion_ops->error_cleanup(&head, desc->pg_error);
}
/**
* __nfs_pageio_add_request - Attempt to coalesce a request into a page list.
* @desc: destination io descriptor
* @req: request
*
* This may split a request into subrequests which are all part of the
* same page group. If so, it will submit @req as the last one, to ensure
* the pointer to @req is still valid in case of failure.
*
* Returns true if the request 'req' was successfully coalesced into the
* existing list of pages 'desc'.
*/
static int __nfs_pageio_add_request(struct nfs_pageio_descriptor *desc,
struct nfs_page *req)
{
struct nfs_pgio_mirror *mirror = nfs_pgio_current_mirror(desc);
struct nfs_page *subreq;
unsigned int size, subreq_size;
nfs_page_group_lock(req);
subreq = req;
subreq_size = subreq->wb_bytes;
for(;;) {
size = nfs_pageio_do_add_request(desc, subreq);
if (size == subreq_size) {
/* We successfully submitted a request */
if (subreq == req)
break;
req->wb_pgbase += size;
req->wb_bytes -= size;
req->wb_offset += size;
subreq_size = req->wb_bytes;
subreq = req;
continue;
}
if (WARN_ON_ONCE(subreq != req)) {
nfs_page_group_unlock(req);
nfs_pageio_cleanup_request(desc, subreq);
subreq = req;
subreq_size = req->wb_bytes;
nfs_page_group_lock(req);
}
if (!size) {
/* Can't coalesce any more, so do I/O */
nfs_page_group_unlock(req);
desc->pg_moreio = 1;
nfs_pageio_doio(desc);
if (desc->pg_error < 0 || mirror->pg_recoalesce)
return 0;
/* retry add_request for this subreq */
nfs_page_group_lock(req);
continue;
}
subreq = nfs_create_subreq(req, req->wb_pgbase,
req->wb_offset, size);
if (IS_ERR(subreq))
goto err_ptr;
subreq_size = size;
}
nfs_page_group_unlock(req);
return 1;
err_ptr:
desc->pg_error = PTR_ERR(subreq);
nfs_page_group_unlock(req);
return 0;
}
static int nfs_do_recoalesce(struct nfs_pageio_descriptor *desc)
{
struct nfs_pgio_mirror *mirror = nfs_pgio_current_mirror(desc);
LIST_HEAD(head);
do {
list_splice_init(&mirror->pg_list, &head);
mirror->pg_recoalesce = 0;
while (!list_empty(&head)) {
struct nfs_page *req;
req = list_first_entry(&head, struct nfs_page, wb_list);
if (__nfs_pageio_add_request(desc, req))
continue;
if (desc->pg_error < 0) {
list_splice_tail(&head, &mirror->pg_list);
mirror->pg_recoalesce = 1;
return 0;
}
break;
}
} while (mirror->pg_recoalesce);
return 1;
}
static int nfs_pageio_add_request_mirror(struct nfs_pageio_descriptor *desc,
struct nfs_page *req)
{
int ret;
do {
ret = __nfs_pageio_add_request(desc, req);
if (ret)
break;
if (desc->pg_error < 0)
break;
ret = nfs_do_recoalesce(desc);
} while (ret);
return ret;
}
static void nfs_pageio_error_cleanup(struct nfs_pageio_descriptor *desc)
{
u32 midx;
struct nfs_pgio_mirror *mirror;
if (!desc->pg_error)
return;
for (midx = 0; midx < desc->pg_mirror_count; midx++) {
mirror = nfs_pgio_get_mirror(desc, midx);
desc->pg_completion_ops->error_cleanup(&mirror->pg_list,
desc->pg_error);
}
}
int nfs_pageio_add_request(struct nfs_pageio_descriptor *desc,
struct nfs_page *req)
{
u32 midx;
unsigned int pgbase, offset, bytes;
struct nfs_page *dupreq;
pgbase = req->wb_pgbase;
offset = req->wb_offset;
bytes = req->wb_bytes;
nfs_pageio_setup_mirroring(desc, req);
if (desc->pg_error < 0)
goto out_failed;
/* Create the mirror instances first, and fire them off */
for (midx = 1; midx < desc->pg_mirror_count; midx++) {
nfs_page_group_lock(req);
dupreq = nfs_create_subreq(req,
pgbase, offset, bytes);
nfs_page_group_unlock(req);
if (IS_ERR(dupreq)) {
desc->pg_error = PTR_ERR(dupreq);
goto out_failed;
}
nfs_pgio_set_current_mirror(desc, midx);
if (!nfs_pageio_add_request_mirror(desc, dupreq))
goto out_cleanup_subreq;
}
nfs_pgio_set_current_mirror(desc, 0);
if (!nfs_pageio_add_request_mirror(desc, req))
goto out_failed;
return 1;
out_cleanup_subreq:
nfs_pageio_cleanup_request(desc, dupreq);
out_failed:
nfs_pageio_error_cleanup(desc);
return 0;
}
/*
* nfs_pageio_complete_mirror - Complete I/O on the current mirror of an
* nfs_pageio_descriptor
* @desc: pointer to io descriptor
* @mirror_idx: pointer to mirror index
*/
static void nfs_pageio_complete_mirror(struct nfs_pageio_descriptor *desc,
u32 mirror_idx)
{
struct nfs_pgio_mirror *mirror;
u32 restore_idx;
restore_idx = nfs_pgio_set_current_mirror(desc, mirror_idx);
mirror = nfs_pgio_current_mirror(desc);
for (;;) {
nfs_pageio_doio(desc);
if (desc->pg_error < 0 || !mirror->pg_recoalesce)
break;
if (!nfs_do_recoalesce(desc))
break;
}
nfs_pgio_set_current_mirror(desc, restore_idx);
}
/*
* nfs_pageio_resend - Transfer requests to new descriptor and resend
* @hdr - the pgio header to move request from
* @desc - the pageio descriptor to add requests to
*
* Try to move each request (nfs_page) from @hdr to @desc then attempt
* to send them.
*
* Returns 0 on success and < 0 on error.
*/
int nfs_pageio_resend(struct nfs_pageio_descriptor *desc,
struct nfs_pgio_header *hdr)
{
LIST_HEAD(pages);
desc->pg_io_completion = hdr->io_completion;
desc->pg_dreq = hdr->dreq;
nfs_netfs_set_pageio_descriptor(desc, hdr);
list_splice_init(&hdr->pages, &pages);
while (!list_empty(&pages)) {
struct nfs_page *req = nfs_list_entry(pages.next);
if (!nfs_pageio_add_request(desc, req))
break;
}
nfs_pageio_complete(desc);
if (!list_empty(&pages)) {
int err = desc->pg_error < 0 ? desc->pg_error : -EIO;
hdr->completion_ops->error_cleanup(&pages, err);
nfs_set_pgio_error(hdr, err, hdr->io_start);
return err;
}
return 0;
}
EXPORT_SYMBOL_GPL(nfs_pageio_resend);
/**
* nfs_pageio_complete - Complete I/O then cleanup an nfs_pageio_descriptor
* @desc: pointer to io descriptor
*/
void nfs_pageio_complete(struct nfs_pageio_descriptor *desc)
{
u32 midx;
for (midx = 0; midx < desc->pg_mirror_count; midx++)
nfs_pageio_complete_mirror(desc, midx);
if (desc->pg_error < 0)
nfs_pageio_error_cleanup(desc);
if (desc->pg_ops->pg_cleanup)
desc->pg_ops->pg_cleanup(desc);
nfs_pageio_cleanup_mirroring(desc);
}
/**
* nfs_pageio_cond_complete - Conditional I/O completion
* @desc: pointer to io descriptor
* @index: page index
*
* It is important to ensure that processes don't try to take locks
* on non-contiguous ranges of pages as that might deadlock. This
* function should be called before attempting to wait on a locked
* nfs_page. It will complete the I/O if the page index 'index'
* is not contiguous with the existing list of pages in 'desc'.
*/
void nfs_pageio_cond_complete(struct nfs_pageio_descriptor *desc, pgoff_t index)
{
struct nfs_pgio_mirror *mirror;
struct nfs_page *prev;
struct folio *folio;
u32 midx;
for (midx = 0; midx < desc->pg_mirror_count; midx++) {
mirror = nfs_pgio_get_mirror(desc, midx);
if (!list_empty(&mirror->pg_list)) {
prev = nfs_list_entry(mirror->pg_list.prev);
folio = nfs_page_to_folio(prev);
if (folio) {
if (index == folio_next_index(folio))
continue;
} else if (index == prev->wb_index + 1)
continue;
/*
* We will submit more requests after these. Indicate
* this to the underlying layers.
*/
desc->pg_moreio = 1;
nfs_pageio_complete(desc);
break;
}
}
}
/*
* nfs_pageio_stop_mirroring - stop using mirroring (set mirror count to 1)
*/
void nfs_pageio_stop_mirroring(struct nfs_pageio_descriptor *pgio)
{
nfs_pageio_complete(pgio);
}
int __init nfs_init_nfspagecache(void)
{
nfs_page_cachep = kmem_cache_create("nfs_page",
sizeof(struct nfs_page),
0, SLAB_HWCACHE_ALIGN,
NULL);
if (nfs_page_cachep == NULL)
return -ENOMEM;
return 0;
}
void nfs_destroy_nfspagecache(void)
{
kmem_cache_destroy(nfs_page_cachep);
}
static const struct rpc_call_ops nfs_pgio_common_ops = {
.rpc_call_prepare = nfs_pgio_prepare,
.rpc_call_done = nfs_pgio_result,
.rpc_release = nfs_pgio_release,
};
const struct nfs_pageio_ops nfs_pgio_rw_ops = {
.pg_test = nfs_generic_pg_test,
.pg_doio = nfs_generic_pg_pgios,
};
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