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![David Howells](/assets/img/avatar_default.png)
Provide fscache_cancel_op() with a pointer to a function it should invoke under lock if it cancels an operation. Use this to clear the remaining page count upon cancellation of a pending retrieval operation so that fscache_release_retrieval_op() doesn't get an assertion failure (see below). This can happen when a signal occurs, say from CTRL-C being pressed during data retrieval. FS-Cache: Assertion failed 3 == 0 is false ------------[ cut here ]------------ kernel BUG at fs/fscache/page.c:237! invalid opcode: 0000 [#641] SMP Modules linked in: cachefiles(F) nfsv4(F) nfsv3(F) nfsv2(F) nfs(F) fscache(F) auth_rpcgss(F) nfs_acl(F) lockd(F) sunrpc(F) CPU 0 Pid: 6075, comm: slurp-q Tainted: GF D 3.7.0-rc8-fsdevel+ #411 /DG965RY RIP: 0010:[<ffffffffa007f328>] [<ffffffffa007f328>] fscache_release_retrieval_op+0x75/0xff [fscache] RSP: 0000:ffff88001c6d7988 EFLAGS: 00010296 RAX: 000000000000000f RBX: ffff880014cdfe00 RCX: ffffffff6c102000 RDX: ffffffff8102d1ad RSI: ffffffff6c102000 RDI: ffffffff8102d1d6 RBP: ffff88001c6d7998 R08: 0000000000000002 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: 00000000fffffe00 R13: ffff88001c6d7ab4 R14: ffff88001a8638a0 R15: ffff88001552b190 FS: 00007f877aaf0700(0000) GS:ffff88003bc00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b CR2: 00007fff11378fd2 CR3: 000000001c6c6000 CR4: 00000000000007f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 Process slurp-q (pid: 6075, threadinfo ffff88001c6d6000, task ffff88001c6c4080) Stack: ffffffffa007ec07 ffff880014cdfe00 ffff88001c6d79c8 ffffffffa007db4d ffffffffa007ec07 ffff880014cdfe00 00000000fffffe00 ffff88001c6d7ab4 ffff88001c6d7a38 ffffffffa008116d 0000000000000000 ffff88001c6c4080 Call Trace: [<ffffffffa007ec07>] ? fscache_cancel_op+0x194/0x1cf [fscache] [<ffffffffa007db4d>] fscache_put_operation+0x135/0x2ed [fscache] [<ffffffffa007ec07>] ? fscache_cancel_op+0x194/0x1cf [fscache] [<ffffffffa008116d>] __fscache_read_or_alloc_pages+0x413/0x4bc [fscache] [<ffffffff810ac8ae>] ? __alloc_pages_nodemask+0x195/0x75c [<ffffffffa00aab0f>] __nfs_readpages_from_fscache+0x86/0x13d [nfs] [<ffffffffa00a5fe0>] nfs_readpages+0x186/0x1bd [nfs] [<ffffffff810d23c8>] ? alloc_pages_current+0xc7/0xe4 [<ffffffff810a68b5>] ? __page_cache_alloc+0x84/0x91 [<ffffffff810af912>] ? __do_page_cache_readahead+0xa6/0x2e0 [<ffffffff810afaa3>] __do_page_cache_readahead+0x237/0x2e0 [<ffffffff810af912>] ? __do_page_cache_readahead+0xa6/0x2e0 [<ffffffff810afe3e>] ra_submit+0x1c/0x20 [<ffffffff810b019b>] ondemand_readahead+0x359/0x382 [<ffffffff810b0279>] page_cache_sync_readahead+0x38/0x3a [<ffffffff810a77b5>] generic_file_aio_read+0x26b/0x637 [<ffffffffa00f1852>] ? nfs_mark_delegation_referenced+0xb/0xb [nfsv4] [<ffffffffa009cc85>] nfs_file_read+0xaa/0xcf [nfs] [<ffffffff810db5b3>] do_sync_read+0x91/0xd1 [<ffffffff810dbb8b>] vfs_read+0x9b/0x144 [<ffffffff810dbc78>] sys_read+0x44/0x75 [<ffffffff81422892>] system_call_fastpath+0x16/0x1b Signed-off-by: David Howells <dhowells@redhat.com>
1117 lines
29 KiB
C
1117 lines
29 KiB
C
/* Cache page management and data I/O routines
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*
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* Copyright (C) 2004-2008 Red Hat, Inc. All Rights Reserved.
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* Written by David Howells (dhowells@redhat.com)
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*/
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#define FSCACHE_DEBUG_LEVEL PAGE
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#include <linux/module.h>
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#include <linux/fscache-cache.h>
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#include <linux/buffer_head.h>
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#include <linux/pagevec.h>
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#include <linux/slab.h>
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#include "internal.h"
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/*
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* check to see if a page is being written to the cache
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*/
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bool __fscache_check_page_write(struct fscache_cookie *cookie, struct page *page)
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{
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void *val;
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rcu_read_lock();
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val = radix_tree_lookup(&cookie->stores, page->index);
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rcu_read_unlock();
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return val != NULL;
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}
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EXPORT_SYMBOL(__fscache_check_page_write);
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/*
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* wait for a page to finish being written to the cache
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*/
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void __fscache_wait_on_page_write(struct fscache_cookie *cookie, struct page *page)
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{
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wait_queue_head_t *wq = bit_waitqueue(&cookie->flags, 0);
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wait_event(*wq, !__fscache_check_page_write(cookie, page));
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}
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EXPORT_SYMBOL(__fscache_wait_on_page_write);
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/*
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* decide whether a page can be released, possibly by cancelling a store to it
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* - we're allowed to sleep if __GFP_WAIT is flagged
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*/
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bool __fscache_maybe_release_page(struct fscache_cookie *cookie,
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struct page *page,
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gfp_t gfp)
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{
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struct page *xpage;
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void *val;
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_enter("%p,%p,%x", cookie, page, gfp);
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try_again:
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rcu_read_lock();
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val = radix_tree_lookup(&cookie->stores, page->index);
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if (!val) {
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rcu_read_unlock();
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fscache_stat(&fscache_n_store_vmscan_not_storing);
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__fscache_uncache_page(cookie, page);
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return true;
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}
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/* see if the page is actually undergoing storage - if so we can't get
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* rid of it till the cache has finished with it */
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if (radix_tree_tag_get(&cookie->stores, page->index,
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FSCACHE_COOKIE_STORING_TAG)) {
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rcu_read_unlock();
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goto page_busy;
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}
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/* the page is pending storage, so we attempt to cancel the store and
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* discard the store request so that the page can be reclaimed */
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spin_lock(&cookie->stores_lock);
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rcu_read_unlock();
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if (radix_tree_tag_get(&cookie->stores, page->index,
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FSCACHE_COOKIE_STORING_TAG)) {
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/* the page started to undergo storage whilst we were looking,
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* so now we can only wait or return */
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spin_unlock(&cookie->stores_lock);
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goto page_busy;
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}
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xpage = radix_tree_delete(&cookie->stores, page->index);
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spin_unlock(&cookie->stores_lock);
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if (xpage) {
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fscache_stat(&fscache_n_store_vmscan_cancelled);
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fscache_stat(&fscache_n_store_radix_deletes);
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ASSERTCMP(xpage, ==, page);
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} else {
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fscache_stat(&fscache_n_store_vmscan_gone);
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}
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wake_up_bit(&cookie->flags, 0);
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if (xpage)
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page_cache_release(xpage);
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__fscache_uncache_page(cookie, page);
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return true;
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page_busy:
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/* We will wait here if we're allowed to, but that could deadlock the
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* allocator as the work threads writing to the cache may all end up
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* sleeping on memory allocation, so we may need to impose a timeout
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* too. */
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if (!(gfp & __GFP_WAIT)) {
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fscache_stat(&fscache_n_store_vmscan_busy);
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return false;
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}
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fscache_stat(&fscache_n_store_vmscan_wait);
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__fscache_wait_on_page_write(cookie, page);
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gfp &= ~__GFP_WAIT;
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goto try_again;
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}
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EXPORT_SYMBOL(__fscache_maybe_release_page);
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/*
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* note that a page has finished being written to the cache
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*/
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static void fscache_end_page_write(struct fscache_object *object,
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struct page *page)
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{
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struct fscache_cookie *cookie;
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struct page *xpage = NULL;
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spin_lock(&object->lock);
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cookie = object->cookie;
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if (cookie) {
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/* delete the page from the tree if it is now no longer
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* pending */
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spin_lock(&cookie->stores_lock);
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radix_tree_tag_clear(&cookie->stores, page->index,
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FSCACHE_COOKIE_STORING_TAG);
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if (!radix_tree_tag_get(&cookie->stores, page->index,
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FSCACHE_COOKIE_PENDING_TAG)) {
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fscache_stat(&fscache_n_store_radix_deletes);
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xpage = radix_tree_delete(&cookie->stores, page->index);
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}
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spin_unlock(&cookie->stores_lock);
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wake_up_bit(&cookie->flags, 0);
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}
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spin_unlock(&object->lock);
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if (xpage)
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page_cache_release(xpage);
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}
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/*
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* actually apply the changed attributes to a cache object
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*/
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static void fscache_attr_changed_op(struct fscache_operation *op)
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{
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struct fscache_object *object = op->object;
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int ret;
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_enter("{OBJ%x OP%x}", object->debug_id, op->debug_id);
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fscache_stat(&fscache_n_attr_changed_calls);
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if (fscache_object_is_active(object)) {
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fscache_stat(&fscache_n_cop_attr_changed);
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ret = object->cache->ops->attr_changed(object);
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fscache_stat_d(&fscache_n_cop_attr_changed);
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if (ret < 0)
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fscache_abort_object(object);
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}
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fscache_op_complete(op, true);
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_leave("");
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}
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/*
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* notification that the attributes on an object have changed
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*/
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int __fscache_attr_changed(struct fscache_cookie *cookie)
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{
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struct fscache_operation *op;
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struct fscache_object *object;
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_enter("%p", cookie);
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ASSERTCMP(cookie->def->type, !=, FSCACHE_COOKIE_TYPE_INDEX);
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fscache_stat(&fscache_n_attr_changed);
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op = kzalloc(sizeof(*op), GFP_KERNEL);
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if (!op) {
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fscache_stat(&fscache_n_attr_changed_nomem);
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_leave(" = -ENOMEM");
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return -ENOMEM;
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}
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fscache_operation_init(op, fscache_attr_changed_op, NULL);
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op->flags = FSCACHE_OP_ASYNC | (1 << FSCACHE_OP_EXCLUSIVE);
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spin_lock(&cookie->lock);
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if (hlist_empty(&cookie->backing_objects))
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goto nobufs;
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object = hlist_entry(cookie->backing_objects.first,
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struct fscache_object, cookie_link);
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if (fscache_submit_exclusive_op(object, op) < 0)
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goto nobufs;
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spin_unlock(&cookie->lock);
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fscache_stat(&fscache_n_attr_changed_ok);
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fscache_put_operation(op);
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_leave(" = 0");
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return 0;
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nobufs:
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spin_unlock(&cookie->lock);
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kfree(op);
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fscache_stat(&fscache_n_attr_changed_nobufs);
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_leave(" = %d", -ENOBUFS);
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return -ENOBUFS;
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}
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EXPORT_SYMBOL(__fscache_attr_changed);
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/*
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* release a retrieval op reference
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*/
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static void fscache_release_retrieval_op(struct fscache_operation *_op)
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{
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struct fscache_retrieval *op =
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container_of(_op, struct fscache_retrieval, op);
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_enter("{OP%x}", op->op.debug_id);
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ASSERTCMP(op->n_pages, ==, 0);
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fscache_hist(fscache_retrieval_histogram, op->start_time);
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if (op->context)
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fscache_put_context(op->op.object->cookie, op->context);
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_leave("");
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}
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/*
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* allocate a retrieval op
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*/
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static struct fscache_retrieval *fscache_alloc_retrieval(
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struct address_space *mapping,
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fscache_rw_complete_t end_io_func,
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void *context)
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{
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struct fscache_retrieval *op;
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/* allocate a retrieval operation and attempt to submit it */
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op = kzalloc(sizeof(*op), GFP_NOIO);
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if (!op) {
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fscache_stat(&fscache_n_retrievals_nomem);
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return NULL;
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}
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fscache_operation_init(&op->op, NULL, fscache_release_retrieval_op);
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op->op.flags = FSCACHE_OP_MYTHREAD | (1 << FSCACHE_OP_WAITING);
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op->mapping = mapping;
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op->end_io_func = end_io_func;
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op->context = context;
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op->start_time = jiffies;
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INIT_LIST_HEAD(&op->to_do);
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return op;
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}
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/*
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* wait for a deferred lookup to complete
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*/
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static int fscache_wait_for_deferred_lookup(struct fscache_cookie *cookie)
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{
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unsigned long jif;
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_enter("");
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if (!test_bit(FSCACHE_COOKIE_LOOKING_UP, &cookie->flags)) {
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_leave(" = 0 [imm]");
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return 0;
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}
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fscache_stat(&fscache_n_retrievals_wait);
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jif = jiffies;
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if (wait_on_bit(&cookie->flags, FSCACHE_COOKIE_LOOKING_UP,
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fscache_wait_bit_interruptible,
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TASK_INTERRUPTIBLE) != 0) {
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fscache_stat(&fscache_n_retrievals_intr);
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_leave(" = -ERESTARTSYS");
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return -ERESTARTSYS;
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}
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ASSERT(!test_bit(FSCACHE_COOKIE_LOOKING_UP, &cookie->flags));
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smp_rmb();
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fscache_hist(fscache_retrieval_delay_histogram, jif);
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_leave(" = 0 [dly]");
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return 0;
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}
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/*
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* Handle cancellation of a pending retrieval op
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*/
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static void fscache_do_cancel_retrieval(struct fscache_operation *_op)
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{
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struct fscache_retrieval *op =
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container_of(_op, struct fscache_retrieval, op);
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op->n_pages = 0;
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}
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/*
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* wait for an object to become active (or dead)
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*/
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static int fscache_wait_for_retrieval_activation(struct fscache_object *object,
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struct fscache_retrieval *op,
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atomic_t *stat_op_waits,
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atomic_t *stat_object_dead)
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{
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int ret;
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if (!test_bit(FSCACHE_OP_WAITING, &op->op.flags))
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goto check_if_dead;
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_debug(">>> WT");
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fscache_stat(stat_op_waits);
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if (wait_on_bit(&op->op.flags, FSCACHE_OP_WAITING,
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fscache_wait_bit_interruptible,
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TASK_INTERRUPTIBLE) != 0) {
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ret = fscache_cancel_op(&op->op, fscache_do_cancel_retrieval);
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if (ret == 0)
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return -ERESTARTSYS;
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/* it's been removed from the pending queue by another party,
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* so we should get to run shortly */
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wait_on_bit(&op->op.flags, FSCACHE_OP_WAITING,
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fscache_wait_bit, TASK_UNINTERRUPTIBLE);
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}
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_debug("<<< GO");
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check_if_dead:
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if (op->op.state == FSCACHE_OP_ST_CANCELLED) {
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fscache_stat(stat_object_dead);
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_leave(" = -ENOBUFS [cancelled]");
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return -ENOBUFS;
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}
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if (unlikely(fscache_object_is_dead(object))) {
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pr_err("%s() = -ENOBUFS [obj dead %d]\n", __func__, op->op.state);
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fscache_cancel_op(&op->op, fscache_do_cancel_retrieval);
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fscache_stat(stat_object_dead);
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return -ENOBUFS;
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}
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return 0;
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}
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/*
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* read a page from the cache or allocate a block in which to store it
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* - we return:
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* -ENOMEM - out of memory, nothing done
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* -ERESTARTSYS - interrupted
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* -ENOBUFS - no backing object available in which to cache the block
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* -ENODATA - no data available in the backing object for this block
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* 0 - dispatched a read - it'll call end_io_func() when finished
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*/
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int __fscache_read_or_alloc_page(struct fscache_cookie *cookie,
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struct page *page,
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fscache_rw_complete_t end_io_func,
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void *context,
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gfp_t gfp)
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{
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struct fscache_retrieval *op;
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struct fscache_object *object;
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int ret;
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_enter("%p,%p,,,", cookie, page);
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fscache_stat(&fscache_n_retrievals);
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if (hlist_empty(&cookie->backing_objects))
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goto nobufs;
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if (test_bit(FSCACHE_COOKIE_INVALIDATING, &cookie->flags)) {
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_leave(" = -ENOBUFS [invalidating]");
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return -ENOBUFS;
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}
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ASSERTCMP(cookie->def->type, !=, FSCACHE_COOKIE_TYPE_INDEX);
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ASSERTCMP(page, !=, NULL);
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if (fscache_wait_for_deferred_lookup(cookie) < 0)
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return -ERESTARTSYS;
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op = fscache_alloc_retrieval(page->mapping, end_io_func, context);
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if (!op) {
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_leave(" = -ENOMEM");
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return -ENOMEM;
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}
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op->n_pages = 1;
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spin_lock(&cookie->lock);
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if (hlist_empty(&cookie->backing_objects))
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goto nobufs_unlock;
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object = hlist_entry(cookie->backing_objects.first,
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struct fscache_object, cookie_link);
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ASSERTCMP(object->state, >, FSCACHE_OBJECT_LOOKING_UP);
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atomic_inc(&object->n_reads);
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__set_bit(FSCACHE_OP_DEC_READ_CNT, &op->op.flags);
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if (fscache_submit_op(object, &op->op) < 0)
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goto nobufs_unlock_dec;
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spin_unlock(&cookie->lock);
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fscache_stat(&fscache_n_retrieval_ops);
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|
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/* pin the netfs read context in case we need to do the actual netfs
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* read because we've encountered a cache read failure */
|
|
fscache_get_context(object->cookie, op->context);
|
|
|
|
/* we wait for the operation to become active, and then process it
|
|
* *here*, in this thread, and not in the thread pool */
|
|
ret = fscache_wait_for_retrieval_activation(
|
|
object, op,
|
|
__fscache_stat(&fscache_n_retrieval_op_waits),
|
|
__fscache_stat(&fscache_n_retrievals_object_dead));
|
|
if (ret < 0)
|
|
goto error;
|
|
|
|
/* ask the cache to honour the operation */
|
|
if (test_bit(FSCACHE_COOKIE_NO_DATA_YET, &object->cookie->flags)) {
|
|
fscache_stat(&fscache_n_cop_allocate_page);
|
|
ret = object->cache->ops->allocate_page(op, page, gfp);
|
|
fscache_stat_d(&fscache_n_cop_allocate_page);
|
|
if (ret == 0)
|
|
ret = -ENODATA;
|
|
} else {
|
|
fscache_stat(&fscache_n_cop_read_or_alloc_page);
|
|
ret = object->cache->ops->read_or_alloc_page(op, page, gfp);
|
|
fscache_stat_d(&fscache_n_cop_read_or_alloc_page);
|
|
}
|
|
|
|
error:
|
|
if (ret == -ENOMEM)
|
|
fscache_stat(&fscache_n_retrievals_nomem);
|
|
else if (ret == -ERESTARTSYS)
|
|
fscache_stat(&fscache_n_retrievals_intr);
|
|
else if (ret == -ENODATA)
|
|
fscache_stat(&fscache_n_retrievals_nodata);
|
|
else if (ret < 0)
|
|
fscache_stat(&fscache_n_retrievals_nobufs);
|
|
else
|
|
fscache_stat(&fscache_n_retrievals_ok);
|
|
|
|
fscache_put_retrieval(op);
|
|
_leave(" = %d", ret);
|
|
return ret;
|
|
|
|
nobufs_unlock_dec:
|
|
atomic_dec(&object->n_reads);
|
|
nobufs_unlock:
|
|
spin_unlock(&cookie->lock);
|
|
kfree(op);
|
|
nobufs:
|
|
fscache_stat(&fscache_n_retrievals_nobufs);
|
|
_leave(" = -ENOBUFS");
|
|
return -ENOBUFS;
|
|
}
|
|
EXPORT_SYMBOL(__fscache_read_or_alloc_page);
|
|
|
|
/*
|
|
* read a list of page from the cache or allocate a block in which to store
|
|
* them
|
|
* - we return:
|
|
* -ENOMEM - out of memory, some pages may be being read
|
|
* -ERESTARTSYS - interrupted, some pages may be being read
|
|
* -ENOBUFS - no backing object or space available in which to cache any
|
|
* pages not being read
|
|
* -ENODATA - no data available in the backing object for some or all of
|
|
* the pages
|
|
* 0 - dispatched a read on all pages
|
|
*
|
|
* end_io_func() will be called for each page read from the cache as it is
|
|
* finishes being read
|
|
*
|
|
* any pages for which a read is dispatched will be removed from pages and
|
|
* nr_pages
|
|
*/
|
|
int __fscache_read_or_alloc_pages(struct fscache_cookie *cookie,
|
|
struct address_space *mapping,
|
|
struct list_head *pages,
|
|
unsigned *nr_pages,
|
|
fscache_rw_complete_t end_io_func,
|
|
void *context,
|
|
gfp_t gfp)
|
|
{
|
|
struct fscache_retrieval *op;
|
|
struct fscache_object *object;
|
|
int ret;
|
|
|
|
_enter("%p,,%d,,,", cookie, *nr_pages);
|
|
|
|
fscache_stat(&fscache_n_retrievals);
|
|
|
|
if (hlist_empty(&cookie->backing_objects))
|
|
goto nobufs;
|
|
|
|
if (test_bit(FSCACHE_COOKIE_INVALIDATING, &cookie->flags)) {
|
|
_leave(" = -ENOBUFS [invalidating]");
|
|
return -ENOBUFS;
|
|
}
|
|
|
|
ASSERTCMP(cookie->def->type, !=, FSCACHE_COOKIE_TYPE_INDEX);
|
|
ASSERTCMP(*nr_pages, >, 0);
|
|
ASSERT(!list_empty(pages));
|
|
|
|
if (fscache_wait_for_deferred_lookup(cookie) < 0)
|
|
return -ERESTARTSYS;
|
|
|
|
op = fscache_alloc_retrieval(mapping, end_io_func, context);
|
|
if (!op)
|
|
return -ENOMEM;
|
|
op->n_pages = *nr_pages;
|
|
|
|
spin_lock(&cookie->lock);
|
|
|
|
if (hlist_empty(&cookie->backing_objects))
|
|
goto nobufs_unlock;
|
|
object = hlist_entry(cookie->backing_objects.first,
|
|
struct fscache_object, cookie_link);
|
|
|
|
atomic_inc(&object->n_reads);
|
|
__set_bit(FSCACHE_OP_DEC_READ_CNT, &op->op.flags);
|
|
|
|
if (fscache_submit_op(object, &op->op) < 0)
|
|
goto nobufs_unlock_dec;
|
|
spin_unlock(&cookie->lock);
|
|
|
|
fscache_stat(&fscache_n_retrieval_ops);
|
|
|
|
/* pin the netfs read context in case we need to do the actual netfs
|
|
* read because we've encountered a cache read failure */
|
|
fscache_get_context(object->cookie, op->context);
|
|
|
|
/* we wait for the operation to become active, and then process it
|
|
* *here*, in this thread, and not in the thread pool */
|
|
ret = fscache_wait_for_retrieval_activation(
|
|
object, op,
|
|
__fscache_stat(&fscache_n_retrieval_op_waits),
|
|
__fscache_stat(&fscache_n_retrievals_object_dead));
|
|
if (ret < 0)
|
|
goto error;
|
|
|
|
/* ask the cache to honour the operation */
|
|
if (test_bit(FSCACHE_COOKIE_NO_DATA_YET, &object->cookie->flags)) {
|
|
fscache_stat(&fscache_n_cop_allocate_pages);
|
|
ret = object->cache->ops->allocate_pages(
|
|
op, pages, nr_pages, gfp);
|
|
fscache_stat_d(&fscache_n_cop_allocate_pages);
|
|
} else {
|
|
fscache_stat(&fscache_n_cop_read_or_alloc_pages);
|
|
ret = object->cache->ops->read_or_alloc_pages(
|
|
op, pages, nr_pages, gfp);
|
|
fscache_stat_d(&fscache_n_cop_read_or_alloc_pages);
|
|
}
|
|
|
|
error:
|
|
if (ret == -ENOMEM)
|
|
fscache_stat(&fscache_n_retrievals_nomem);
|
|
else if (ret == -ERESTARTSYS)
|
|
fscache_stat(&fscache_n_retrievals_intr);
|
|
else if (ret == -ENODATA)
|
|
fscache_stat(&fscache_n_retrievals_nodata);
|
|
else if (ret < 0)
|
|
fscache_stat(&fscache_n_retrievals_nobufs);
|
|
else
|
|
fscache_stat(&fscache_n_retrievals_ok);
|
|
|
|
fscache_put_retrieval(op);
|
|
_leave(" = %d", ret);
|
|
return ret;
|
|
|
|
nobufs_unlock_dec:
|
|
atomic_dec(&object->n_reads);
|
|
nobufs_unlock:
|
|
spin_unlock(&cookie->lock);
|
|
kfree(op);
|
|
nobufs:
|
|
fscache_stat(&fscache_n_retrievals_nobufs);
|
|
_leave(" = -ENOBUFS");
|
|
return -ENOBUFS;
|
|
}
|
|
EXPORT_SYMBOL(__fscache_read_or_alloc_pages);
|
|
|
|
/*
|
|
* allocate a block in the cache on which to store a page
|
|
* - we return:
|
|
* -ENOMEM - out of memory, nothing done
|
|
* -ERESTARTSYS - interrupted
|
|
* -ENOBUFS - no backing object available in which to cache the block
|
|
* 0 - block allocated
|
|
*/
|
|
int __fscache_alloc_page(struct fscache_cookie *cookie,
|
|
struct page *page,
|
|
gfp_t gfp)
|
|
{
|
|
struct fscache_retrieval *op;
|
|
struct fscache_object *object;
|
|
int ret;
|
|
|
|
_enter("%p,%p,,,", cookie, page);
|
|
|
|
fscache_stat(&fscache_n_allocs);
|
|
|
|
if (hlist_empty(&cookie->backing_objects))
|
|
goto nobufs;
|
|
|
|
ASSERTCMP(cookie->def->type, !=, FSCACHE_COOKIE_TYPE_INDEX);
|
|
ASSERTCMP(page, !=, NULL);
|
|
|
|
if (test_bit(FSCACHE_COOKIE_INVALIDATING, &cookie->flags)) {
|
|
_leave(" = -ENOBUFS [invalidating]");
|
|
return -ENOBUFS;
|
|
}
|
|
|
|
if (fscache_wait_for_deferred_lookup(cookie) < 0)
|
|
return -ERESTARTSYS;
|
|
|
|
op = fscache_alloc_retrieval(page->mapping, NULL, NULL);
|
|
if (!op)
|
|
return -ENOMEM;
|
|
op->n_pages = 1;
|
|
|
|
spin_lock(&cookie->lock);
|
|
|
|
if (hlist_empty(&cookie->backing_objects))
|
|
goto nobufs_unlock;
|
|
object = hlist_entry(cookie->backing_objects.first,
|
|
struct fscache_object, cookie_link);
|
|
|
|
if (fscache_submit_op(object, &op->op) < 0)
|
|
goto nobufs_unlock;
|
|
spin_unlock(&cookie->lock);
|
|
|
|
fscache_stat(&fscache_n_alloc_ops);
|
|
|
|
ret = fscache_wait_for_retrieval_activation(
|
|
object, op,
|
|
__fscache_stat(&fscache_n_alloc_op_waits),
|
|
__fscache_stat(&fscache_n_allocs_object_dead));
|
|
if (ret < 0)
|
|
goto error;
|
|
|
|
/* ask the cache to honour the operation */
|
|
fscache_stat(&fscache_n_cop_allocate_page);
|
|
ret = object->cache->ops->allocate_page(op, page, gfp);
|
|
fscache_stat_d(&fscache_n_cop_allocate_page);
|
|
|
|
error:
|
|
if (ret == -ERESTARTSYS)
|
|
fscache_stat(&fscache_n_allocs_intr);
|
|
else if (ret < 0)
|
|
fscache_stat(&fscache_n_allocs_nobufs);
|
|
else
|
|
fscache_stat(&fscache_n_allocs_ok);
|
|
|
|
fscache_put_retrieval(op);
|
|
_leave(" = %d", ret);
|
|
return ret;
|
|
|
|
nobufs_unlock:
|
|
spin_unlock(&cookie->lock);
|
|
kfree(op);
|
|
nobufs:
|
|
fscache_stat(&fscache_n_allocs_nobufs);
|
|
_leave(" = -ENOBUFS");
|
|
return -ENOBUFS;
|
|
}
|
|
EXPORT_SYMBOL(__fscache_alloc_page);
|
|
|
|
/*
|
|
* release a write op reference
|
|
*/
|
|
static void fscache_release_write_op(struct fscache_operation *_op)
|
|
{
|
|
_enter("{OP%x}", _op->debug_id);
|
|
}
|
|
|
|
/*
|
|
* perform the background storage of a page into the cache
|
|
*/
|
|
static void fscache_write_op(struct fscache_operation *_op)
|
|
{
|
|
struct fscache_storage *op =
|
|
container_of(_op, struct fscache_storage, op);
|
|
struct fscache_object *object = op->op.object;
|
|
struct fscache_cookie *cookie;
|
|
struct page *page;
|
|
unsigned n;
|
|
void *results[1];
|
|
int ret;
|
|
|
|
_enter("{OP%x,%d}", op->op.debug_id, atomic_read(&op->op.usage));
|
|
|
|
spin_lock(&object->lock);
|
|
cookie = object->cookie;
|
|
|
|
if (!fscache_object_is_active(object)) {
|
|
/* If we get here, then the on-disk cache object likely longer
|
|
* exists, so we should just cancel this write operation.
|
|
*/
|
|
spin_unlock(&object->lock);
|
|
fscache_op_complete(&op->op, false);
|
|
_leave(" [inactive]");
|
|
return;
|
|
}
|
|
|
|
if (!cookie) {
|
|
/* If we get here, then the cookie belonging to the object was
|
|
* detached, probably by the cookie being withdrawn due to
|
|
* memory pressure, which means that the pages we might write
|
|
* to the cache from no longer exist - therefore, we can just
|
|
* cancel this write operation.
|
|
*/
|
|
spin_unlock(&object->lock);
|
|
fscache_op_complete(&op->op, false);
|
|
_leave(" [cancel] op{f=%lx s=%u} obj{s=%u f=%lx}",
|
|
_op->flags, _op->state, object->state, object->flags);
|
|
return;
|
|
}
|
|
|
|
spin_lock(&cookie->stores_lock);
|
|
|
|
fscache_stat(&fscache_n_store_calls);
|
|
|
|
/* find a page to store */
|
|
page = NULL;
|
|
n = radix_tree_gang_lookup_tag(&cookie->stores, results, 0, 1,
|
|
FSCACHE_COOKIE_PENDING_TAG);
|
|
if (n != 1)
|
|
goto superseded;
|
|
page = results[0];
|
|
_debug("gang %d [%lx]", n, page->index);
|
|
if (page->index > op->store_limit) {
|
|
fscache_stat(&fscache_n_store_pages_over_limit);
|
|
goto superseded;
|
|
}
|
|
|
|
radix_tree_tag_set(&cookie->stores, page->index,
|
|
FSCACHE_COOKIE_STORING_TAG);
|
|
radix_tree_tag_clear(&cookie->stores, page->index,
|
|
FSCACHE_COOKIE_PENDING_TAG);
|
|
|
|
spin_unlock(&cookie->stores_lock);
|
|
spin_unlock(&object->lock);
|
|
|
|
fscache_stat(&fscache_n_store_pages);
|
|
fscache_stat(&fscache_n_cop_write_page);
|
|
ret = object->cache->ops->write_page(op, page);
|
|
fscache_stat_d(&fscache_n_cop_write_page);
|
|
fscache_end_page_write(object, page);
|
|
if (ret < 0) {
|
|
fscache_abort_object(object);
|
|
fscache_op_complete(&op->op, true);
|
|
} else {
|
|
fscache_enqueue_operation(&op->op);
|
|
}
|
|
|
|
_leave("");
|
|
return;
|
|
|
|
superseded:
|
|
/* this writer is going away and there aren't any more things to
|
|
* write */
|
|
_debug("cease");
|
|
spin_unlock(&cookie->stores_lock);
|
|
clear_bit(FSCACHE_OBJECT_PENDING_WRITE, &object->flags);
|
|
spin_unlock(&object->lock);
|
|
fscache_op_complete(&op->op, true);
|
|
_leave("");
|
|
}
|
|
|
|
/*
|
|
* Clear the pages pending writing for invalidation
|
|
*/
|
|
void fscache_invalidate_writes(struct fscache_cookie *cookie)
|
|
{
|
|
struct page *page;
|
|
void *results[16];
|
|
int n, i;
|
|
|
|
_enter("");
|
|
|
|
while (spin_lock(&cookie->stores_lock),
|
|
n = radix_tree_gang_lookup_tag(&cookie->stores, results, 0,
|
|
ARRAY_SIZE(results),
|
|
FSCACHE_COOKIE_PENDING_TAG),
|
|
n > 0) {
|
|
for (i = n - 1; i >= 0; i--) {
|
|
page = results[i];
|
|
radix_tree_delete(&cookie->stores, page->index);
|
|
}
|
|
|
|
spin_unlock(&cookie->stores_lock);
|
|
|
|
for (i = n - 1; i >= 0; i--)
|
|
page_cache_release(results[i]);
|
|
}
|
|
|
|
spin_unlock(&cookie->stores_lock);
|
|
_leave("");
|
|
}
|
|
|
|
/*
|
|
* request a page be stored in the cache
|
|
* - returns:
|
|
* -ENOMEM - out of memory, nothing done
|
|
* -ENOBUFS - no backing object available in which to cache the page
|
|
* 0 - dispatched a write - it'll call end_io_func() when finished
|
|
*
|
|
* if the cookie still has a backing object at this point, that object can be
|
|
* in one of a few states with respect to storage processing:
|
|
*
|
|
* (1) negative lookup, object not yet created (FSCACHE_COOKIE_CREATING is
|
|
* set)
|
|
*
|
|
* (a) no writes yet (set FSCACHE_COOKIE_PENDING_FILL and queue deferred
|
|
* fill op)
|
|
*
|
|
* (b) writes deferred till post-creation (mark page for writing and
|
|
* return immediately)
|
|
*
|
|
* (2) negative lookup, object created, initial fill being made from netfs
|
|
* (FSCACHE_COOKIE_INITIAL_FILL is set)
|
|
*
|
|
* (a) fill point not yet reached this page (mark page for writing and
|
|
* return)
|
|
*
|
|
* (b) fill point passed this page (queue op to store this page)
|
|
*
|
|
* (3) object extant (queue op to store this page)
|
|
*
|
|
* any other state is invalid
|
|
*/
|
|
int __fscache_write_page(struct fscache_cookie *cookie,
|
|
struct page *page,
|
|
gfp_t gfp)
|
|
{
|
|
struct fscache_storage *op;
|
|
struct fscache_object *object;
|
|
int ret;
|
|
|
|
_enter("%p,%x,", cookie, (u32) page->flags);
|
|
|
|
ASSERTCMP(cookie->def->type, !=, FSCACHE_COOKIE_TYPE_INDEX);
|
|
ASSERT(PageFsCache(page));
|
|
|
|
fscache_stat(&fscache_n_stores);
|
|
|
|
if (test_bit(FSCACHE_COOKIE_INVALIDATING, &cookie->flags)) {
|
|
_leave(" = -ENOBUFS [invalidating]");
|
|
return -ENOBUFS;
|
|
}
|
|
|
|
op = kzalloc(sizeof(*op), GFP_NOIO | __GFP_NOMEMALLOC | __GFP_NORETRY);
|
|
if (!op)
|
|
goto nomem;
|
|
|
|
fscache_operation_init(&op->op, fscache_write_op,
|
|
fscache_release_write_op);
|
|
op->op.flags = FSCACHE_OP_ASYNC | (1 << FSCACHE_OP_WAITING);
|
|
|
|
ret = radix_tree_preload(gfp & ~__GFP_HIGHMEM);
|
|
if (ret < 0)
|
|
goto nomem_free;
|
|
|
|
ret = -ENOBUFS;
|
|
spin_lock(&cookie->lock);
|
|
|
|
if (hlist_empty(&cookie->backing_objects))
|
|
goto nobufs;
|
|
object = hlist_entry(cookie->backing_objects.first,
|
|
struct fscache_object, cookie_link);
|
|
if (test_bit(FSCACHE_IOERROR, &object->cache->flags))
|
|
goto nobufs;
|
|
|
|
/* add the page to the pending-storage radix tree on the backing
|
|
* object */
|
|
spin_lock(&object->lock);
|
|
spin_lock(&cookie->stores_lock);
|
|
|
|
_debug("store limit %llx", (unsigned long long) object->store_limit);
|
|
|
|
ret = radix_tree_insert(&cookie->stores, page->index, page);
|
|
if (ret < 0) {
|
|
if (ret == -EEXIST)
|
|
goto already_queued;
|
|
_debug("insert failed %d", ret);
|
|
goto nobufs_unlock_obj;
|
|
}
|
|
|
|
radix_tree_tag_set(&cookie->stores, page->index,
|
|
FSCACHE_COOKIE_PENDING_TAG);
|
|
page_cache_get(page);
|
|
|
|
/* we only want one writer at a time, but we do need to queue new
|
|
* writers after exclusive ops */
|
|
if (test_and_set_bit(FSCACHE_OBJECT_PENDING_WRITE, &object->flags))
|
|
goto already_pending;
|
|
|
|
spin_unlock(&cookie->stores_lock);
|
|
spin_unlock(&object->lock);
|
|
|
|
op->op.debug_id = atomic_inc_return(&fscache_op_debug_id);
|
|
op->store_limit = object->store_limit;
|
|
|
|
if (fscache_submit_op(object, &op->op) < 0)
|
|
goto submit_failed;
|
|
|
|
spin_unlock(&cookie->lock);
|
|
radix_tree_preload_end();
|
|
fscache_stat(&fscache_n_store_ops);
|
|
fscache_stat(&fscache_n_stores_ok);
|
|
|
|
/* the work queue now carries its own ref on the object */
|
|
fscache_put_operation(&op->op);
|
|
_leave(" = 0");
|
|
return 0;
|
|
|
|
already_queued:
|
|
fscache_stat(&fscache_n_stores_again);
|
|
already_pending:
|
|
spin_unlock(&cookie->stores_lock);
|
|
spin_unlock(&object->lock);
|
|
spin_unlock(&cookie->lock);
|
|
radix_tree_preload_end();
|
|
kfree(op);
|
|
fscache_stat(&fscache_n_stores_ok);
|
|
_leave(" = 0");
|
|
return 0;
|
|
|
|
submit_failed:
|
|
spin_lock(&cookie->stores_lock);
|
|
radix_tree_delete(&cookie->stores, page->index);
|
|
spin_unlock(&cookie->stores_lock);
|
|
page_cache_release(page);
|
|
ret = -ENOBUFS;
|
|
goto nobufs;
|
|
|
|
nobufs_unlock_obj:
|
|
spin_unlock(&cookie->stores_lock);
|
|
spin_unlock(&object->lock);
|
|
nobufs:
|
|
spin_unlock(&cookie->lock);
|
|
radix_tree_preload_end();
|
|
kfree(op);
|
|
fscache_stat(&fscache_n_stores_nobufs);
|
|
_leave(" = -ENOBUFS");
|
|
return -ENOBUFS;
|
|
|
|
nomem_free:
|
|
kfree(op);
|
|
nomem:
|
|
fscache_stat(&fscache_n_stores_oom);
|
|
_leave(" = -ENOMEM");
|
|
return -ENOMEM;
|
|
}
|
|
EXPORT_SYMBOL(__fscache_write_page);
|
|
|
|
/*
|
|
* remove a page from the cache
|
|
*/
|
|
void __fscache_uncache_page(struct fscache_cookie *cookie, struct page *page)
|
|
{
|
|
struct fscache_object *object;
|
|
|
|
_enter(",%p", page);
|
|
|
|
ASSERTCMP(cookie->def->type, !=, FSCACHE_COOKIE_TYPE_INDEX);
|
|
ASSERTCMP(page, !=, NULL);
|
|
|
|
fscache_stat(&fscache_n_uncaches);
|
|
|
|
/* cache withdrawal may beat us to it */
|
|
if (!PageFsCache(page))
|
|
goto done;
|
|
|
|
/* get the object */
|
|
spin_lock(&cookie->lock);
|
|
|
|
if (hlist_empty(&cookie->backing_objects)) {
|
|
ClearPageFsCache(page);
|
|
goto done_unlock;
|
|
}
|
|
|
|
object = hlist_entry(cookie->backing_objects.first,
|
|
struct fscache_object, cookie_link);
|
|
|
|
/* there might now be stuff on disk we could read */
|
|
clear_bit(FSCACHE_COOKIE_NO_DATA_YET, &cookie->flags);
|
|
|
|
/* only invoke the cache backend if we managed to mark the page
|
|
* uncached here; this deals with synchronisation vs withdrawal */
|
|
if (TestClearPageFsCache(page) &&
|
|
object->cache->ops->uncache_page) {
|
|
/* the cache backend releases the cookie lock */
|
|
fscache_stat(&fscache_n_cop_uncache_page);
|
|
object->cache->ops->uncache_page(object, page);
|
|
fscache_stat_d(&fscache_n_cop_uncache_page);
|
|
goto done;
|
|
}
|
|
|
|
done_unlock:
|
|
spin_unlock(&cookie->lock);
|
|
done:
|
|
_leave("");
|
|
}
|
|
EXPORT_SYMBOL(__fscache_uncache_page);
|
|
|
|
/**
|
|
* fscache_mark_page_cached - Mark a page as being cached
|
|
* @op: The retrieval op pages are being marked for
|
|
* @page: The page to be marked
|
|
*
|
|
* Mark a netfs page as being cached. After this is called, the netfs
|
|
* must call fscache_uncache_page() to remove the mark.
|
|
*/
|
|
void fscache_mark_page_cached(struct fscache_retrieval *op, struct page *page)
|
|
{
|
|
struct fscache_cookie *cookie = op->op.object->cookie;
|
|
|
|
#ifdef CONFIG_FSCACHE_STATS
|
|
atomic_inc(&fscache_n_marks);
|
|
#endif
|
|
|
|
_debug("- mark %p{%lx}", page, page->index);
|
|
if (TestSetPageFsCache(page)) {
|
|
static bool once_only;
|
|
if (!once_only) {
|
|
once_only = true;
|
|
printk(KERN_WARNING "FS-Cache:"
|
|
" Cookie type %s marked page %lx"
|
|
" multiple times\n",
|
|
cookie->def->name, page->index);
|
|
}
|
|
}
|
|
|
|
if (cookie->def->mark_page_cached)
|
|
cookie->def->mark_page_cached(cookie->netfs_data,
|
|
op->mapping, page);
|
|
}
|
|
EXPORT_SYMBOL(fscache_mark_page_cached);
|
|
|
|
/**
|
|
* fscache_mark_pages_cached - Mark pages as being cached
|
|
* @op: The retrieval op pages are being marked for
|
|
* @pagevec: The pages to be marked
|
|
*
|
|
* Mark a bunch of netfs pages as being cached. After this is called,
|
|
* the netfs must call fscache_uncache_page() to remove the mark.
|
|
*/
|
|
void fscache_mark_pages_cached(struct fscache_retrieval *op,
|
|
struct pagevec *pagevec)
|
|
{
|
|
unsigned long loop;
|
|
|
|
for (loop = 0; loop < pagevec->nr; loop++)
|
|
fscache_mark_page_cached(op, pagevec->pages[loop]);
|
|
|
|
pagevec_reinit(pagevec);
|
|
}
|
|
EXPORT_SYMBOL(fscache_mark_pages_cached);
|
|
|
|
/*
|
|
* Uncache all the pages in an inode that are marked PG_fscache, assuming them
|
|
* to be associated with the given cookie.
|
|
*/
|
|
void __fscache_uncache_all_inode_pages(struct fscache_cookie *cookie,
|
|
struct inode *inode)
|
|
{
|
|
struct address_space *mapping = inode->i_mapping;
|
|
struct pagevec pvec;
|
|
pgoff_t next;
|
|
int i;
|
|
|
|
_enter("%p,%p", cookie, inode);
|
|
|
|
if (!mapping || mapping->nrpages == 0) {
|
|
_leave(" [no pages]");
|
|
return;
|
|
}
|
|
|
|
pagevec_init(&pvec, 0);
|
|
next = 0;
|
|
do {
|
|
if (!pagevec_lookup(&pvec, mapping, next, PAGEVEC_SIZE))
|
|
break;
|
|
for (i = 0; i < pagevec_count(&pvec); i++) {
|
|
struct page *page = pvec.pages[i];
|
|
next = page->index;
|
|
if (PageFsCache(page)) {
|
|
__fscache_wait_on_page_write(cookie, page);
|
|
__fscache_uncache_page(cookie, page);
|
|
}
|
|
}
|
|
pagevec_release(&pvec);
|
|
cond_resched();
|
|
} while (++next);
|
|
|
|
_leave("");
|
|
}
|
|
EXPORT_SYMBOL(__fscache_uncache_all_inode_pages);
|