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Btrfs: Do metadata checksums for reads via a workqueue

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Before, metadata checksumming was done by the callers of read_tree_block,
which would set EXTENT_CSUM bits in the extent tree to show that a given
range of pages was already checksummed and didn't need to be verified
again.

But, those bits could go away via try_to_releasepage, and the end
result was bogus checksum failures on pages that never left the cache.

The new code validates checksums when the page is read.  It is a little
tricky because metadata blocks can span pages and a single read may
end up going via multiple bios.

Signed-off-by: Chris Mason <chris.mason@oracle.com>
This commit is contained in:
Chris Mason 2008-04-09 16:28:12 -04:00
parent 728131d8e4
commit ce9adaa5a7
7 changed files with 310 additions and 67 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

5
fs/btrfs/ctree.c
View File

@ -158,9 +158,6 @@ int __btrfs_cow_block(struct btrfs_trans_handle *trans,
} else {
root_gen = 0;
}
if (!(buf->flags & EXTENT_CSUM))
WARN_ON(1);
WARN_ON(root->ref_cows && trans->transid !=
root->fs_info->running_transaction->transid);
WARN_ON(root->ref_cows && trans->transid != root->last_trans);
@ -247,8 +244,6 @@ int btrfs_cow_block(struct btrfs_trans_handle *trans,
root->fs_info->generation);
WARN_ON(1);
}
if (!(buf->flags & EXTENT_CSUM))
WARN_ON(1);
header_trans = btrfs_header_generation(buf);
spin_lock(&root->fs_info->hash_lock);

4
fs/btrfs/ctree.h
View File

@ -485,6 +485,10 @@ struct btrfs_fs_info {
struct list_head trans_list;
struct list_head hashers;
struct list_head dead_roots;
struct list_head end_io_work_list;
struct work_struct end_io_work;
spinlock_t end_io_work_lock;
#if LINUX_VERSION_CODE <= KERNEL_VERSION(2,6,18)
struct work_struct trans_work;
#else

258
fs/btrfs/disk-io.c
View File

@ -24,6 +24,7 @@
#include <linux/radix-tree.h>
#include <linux/writeback.h>
#include <linux/buffer_head.h> // for block_sync_page
#include <linux/workqueue.h>
#include "ctree.h"
#include "disk-io.h"
#include "transaction.h"
@ -45,6 +46,16 @@ static int check_tree_block(struct btrfs_root *root, struct extent_buffer *buf)
#endif
static struct extent_io_ops btree_extent_io_ops;
static struct workqueue_struct *end_io_workqueue;
struct end_io_wq {
struct bio *bio;
bio_end_io_t *end_io;
void *private;
struct btrfs_fs_info *info;
int error;
struct list_head list;
};
struct extent_map *btree_get_extent(struct inode *inode, struct page *page,
size_t page_offset, u64 start, u64 len,
@ -219,11 +230,108 @@ static int btree_writepage_io_hook(struct page *page, u64 start, u64 end)
return 0;
}
int btree_readpage_end_io_hook(struct page *page, u64 start, u64 end,
struct extent_state *state)
{
struct extent_io_tree *tree;
u64 found_start;
int found_level;
unsigned long len;
struct extent_buffer *eb;
struct btrfs_root *root = BTRFS_I(page->mapping->host)->root;
int ret;
tree = &BTRFS_I(page->mapping->host)->io_tree;
if (page->private == EXTENT_PAGE_PRIVATE)
goto out;
if (!page->private)
goto out;
len = page->private >> 2;
if (len == 0) {
WARN_ON(1);
}
eb = alloc_extent_buffer(tree, start, len, page, GFP_NOFS);
read_extent_buffer_pages(tree, eb, start + PAGE_CACHE_SIZE, 1,
btree_get_extent);
btrfs_clear_buffer_defrag(eb);
found_start = btrfs_header_bytenr(eb);
if (found_start != start) {
printk("warning: eb start incorrect %Lu buffer %Lu len %lu\n",
start, found_start, len);
WARN_ON(1);
goto err;
}
if (eb->first_page != page) {
printk("bad first page %lu %lu\n", eb->first_page->index,
page->index);
WARN_ON(1);
goto err;
}
found_level = btrfs_header_level(eb);
ret = csum_tree_block(root, eb, 1);
end = min_t(u64, eb->len, PAGE_CACHE_SIZE);
end = eb->start + end - 1;
release_extent_buffer_tail_pages(eb);
err:
free_extent_buffer(eb);
out:
return 0;
}
#if LINUX_VERSION_CODE > KERNEL_VERSION(2,6,23)
static void end_workqueue_bio(struct bio *bio, int err)
#else
static int end_workqueue_bio(struct bio *bio,
unsigned int bytes_done, int err)
#endif
{
struct end_io_wq *end_io_wq = bio->bi_private;
struct btrfs_fs_info *fs_info;
unsigned long flags;
#if LINUX_VERSION_CODE <= KERNEL_VERSION(2,6,23)
if (bio->bi_size)
return 1;
#endif
fs_info = end_io_wq->info;
spin_lock_irqsave(&fs_info->end_io_work_lock, flags);
end_io_wq->error = err;
list_add_tail(&end_io_wq->list, &fs_info->end_io_work_list);
spin_unlock_irqrestore(&fs_info->end_io_work_lock, flags);
queue_work(end_io_workqueue, &fs_info->end_io_work);
#if LINUX_VERSION_CODE <= KERNEL_VERSION(2,6,23)
return 0;
#endif
}
static int btree_submit_bio_hook(struct inode *inode, int rw, struct bio *bio)
{
struct btrfs_root *root = BTRFS_I(inode)->root;
struct end_io_wq *end_io_wq;
u64 offset;
offset = bio->bi_sector << 9;
if (rw & (1 << BIO_RW)) {
return btrfs_map_bio(BTRFS_I(inode)->root, rw, bio);
}
end_io_wq = kmalloc(sizeof(*end_io_wq), GFP_NOFS);
if (!end_io_wq)
return -ENOMEM;
end_io_wq->private = bio->bi_private;
end_io_wq->end_io = bio->bi_end_io;
end_io_wq->info = root->fs_info;
end_io_wq->error = 0;
end_io_wq->bio = bio;
bio->bi_private = end_io_wq;
bio->bi_end_io = end_workqueue_bio;
if (offset == BTRFS_SUPER_INFO_OFFSET) {
bio->bi_bdev = root->fs_info->sb->s_bdev;
submit_bio(rw, bio);
@ -363,36 +471,7 @@ static int close_all_devices(struct btrfs_fs_info *fs_info)
int btrfs_verify_block_csum(struct btrfs_root *root,
struct extent_buffer *buf)
{
struct extent_io_tree *io_tree;
u64 end;
int ret;
io_tree = &BTRFS_I(root->fs_info->btree_inode)->io_tree;
if (buf->flags & EXTENT_CSUM)
return 0;
end = min_t(u64, buf->len, PAGE_CACHE_SIZE);
end = buf->start + end - 1;
if (test_range_bit(io_tree, buf->start, end, EXTENT_CSUM, 1)) {
buf->flags |= EXTENT_CSUM;
return 0;
}
lock_extent(io_tree, buf->start, end, GFP_NOFS);
if (test_range_bit(io_tree, buf->start, end, EXTENT_CSUM, 1)) {
buf->flags |= EXTENT_CSUM;
ret = 0;
goto out_unlock;
}
WARN_ON(buf->flags & EXTENT_CSUM);
ret = csum_tree_block(root, buf, 1);
set_extent_bits(io_tree, buf->start, end, EXTENT_CSUM, GFP_NOFS);
buf->flags |= EXTENT_CSUM;
out_unlock:
unlock_extent(io_tree, buf->start, end, GFP_NOFS);
return ret;
return btrfs_buffer_uptodate(buf);
}
struct extent_buffer *btrfs_find_tree_block(struct btrfs_root *root,
@ -430,11 +509,15 @@ struct extent_buffer *read_tree_block(struct btrfs_root *root, u64 bytenr,
buf = btrfs_find_create_tree_block(root, bytenr, blocksize);
if (!buf)
return NULL;
read_extent_buffer_pages(&BTRFS_I(btree_inode)->io_tree, buf, 0, 1,
btree_get_extent);
ret = btrfs_verify_block_csum(root, buf);
ret = read_extent_buffer_pages(&BTRFS_I(btree_inode)->io_tree, buf, 0,
1, btree_get_extent);
if (ret == 0) {
buf->flags |= EXTENT_UPTODATE;
}
return buf;
}
int clean_tree_block(struct btrfs_trans_handle *trans, struct btrfs_root *root,
@ -724,6 +807,99 @@ static int setup_bdi(struct btrfs_fs_info *info, struct backing_dev_info *bdi)
return 0;
}
static int bio_ready_for_csum(struct bio *bio)
{
u64 length = 0;
u64 buf_len = 0;
u64 start = 0;
struct page *page;
struct extent_io_tree *io_tree = NULL;
struct btrfs_fs_info *info = NULL;
struct bio_vec *bvec;
int i;
int ret;
bio_for_each_segment(bvec, bio, i) {
page = bvec->bv_page;
if (page->private == EXTENT_PAGE_PRIVATE) {
length += bvec->bv_len;
continue;
}
if (!page->private) {
length += bvec->bv_len;
continue;
}
length = bvec->bv_len;
buf_len = page->private >> 2;
start = page_offset(page) + bvec->bv_offset;
io_tree = &BTRFS_I(page->mapping->host)->io_tree;
info = BTRFS_I(page->mapping->host)->root->fs_info;
}
/* are we fully contained in this bio? */
if (buf_len <= length)
return 1;
ret = extent_range_uptodate(io_tree, start + length,
start + buf_len - 1);
if (ret == 1)
return ret;
return ret;
}
#if LINUX_VERSION_CODE <= KERNEL_VERSION(2,6,18)
void btrfs_end_io_csum(void *p)
#else
void btrfs_end_io_csum(struct work_struct *work)
#endif
{
#if LINUX_VERSION_CODE <= KERNEL_VERSION(2,6,18)
struct btrfs_fs_info *fs_info = p;
#else
struct btrfs_fs_info *fs_info = container_of(work,
struct btrfs_fs_info,
end_io_work);
#endif
unsigned long flags;
struct end_io_wq *end_io_wq;
struct bio *bio;
struct list_head *next;
int error;
int was_empty;
while(1) {
spin_lock_irqsave(&fs_info->end_io_work_lock, flags);
if (list_empty(&fs_info->end_io_work_list)) {
spin_unlock_irqrestore(&fs_info->end_io_work_lock,
flags);
return;
}
next = fs_info->end_io_work_list.next;
list_del(next);
spin_unlock_irqrestore(&fs_info->end_io_work_lock, flags);
end_io_wq = list_entry(next, struct end_io_wq, list);
bio = end_io_wq->bio;
if (!bio_ready_for_csum(bio)) {
spin_lock_irqsave(&fs_info->end_io_work_lock, flags);
was_empty = list_empty(&fs_info->end_io_work_list);
list_add_tail(&end_io_wq->list,
&fs_info->end_io_work_list);
spin_unlock_irqrestore(&fs_info->end_io_work_lock,
flags);
if (was_empty)
return;
continue;
}
error = end_io_wq->error;
bio->bi_private = end_io_wq->private;
bio->bi_end_io = end_io_wq->end_io;
kfree(end_io_wq);
bio_endio(bio, error);
}
}
struct btrfs_root *open_ctree(struct super_block *sb,
struct btrfs_fs_devices *fs_devices)
{
@ -750,11 +926,16 @@ struct btrfs_root *open_ctree(struct super_block *sb,
err = -ENOMEM;
goto fail;
}
end_io_workqueue = create_workqueue("btrfs-end-io");
BUG_ON(!end_io_workqueue);
INIT_RADIX_TREE(&fs_info->fs_roots_radix, GFP_NOFS);
INIT_LIST_HEAD(&fs_info->trans_list);
INIT_LIST_HEAD(&fs_info->dead_roots);
INIT_LIST_HEAD(&fs_info->hashers);
INIT_LIST_HEAD(&fs_info->end_io_work_list);
spin_lock_init(&fs_info->hash_lock);
spin_lock_init(&fs_info->end_io_work_lock);
spin_lock_init(&fs_info->delalloc_lock);
spin_lock_init(&fs_info->new_trans_lock);
@ -799,6 +980,7 @@ struct btrfs_root *open_ctree(struct super_block *sb,
fs_info->btree_inode->i_mapping, GFP_NOFS);
fs_info->do_barriers = 1;
INIT_WORK(&fs_info->end_io_work, btrfs_end_io_csum);
#if LINUX_VERSION_CODE <= KERNEL_VERSION(2,6,18)
INIT_WORK(&fs_info->trans_work, btrfs_transaction_cleaner, fs_info);
#else
@ -1044,6 +1226,8 @@ int close_ctree(struct btrfs_root *root)
extent_io_tree_empty_lru(&BTRFS_I(fs_info->btree_inode)->io_tree);
truncate_inode_pages(fs_info->btree_inode->i_mapping, 0);
flush_workqueue(end_io_workqueue);
destroy_workqueue(end_io_workqueue);
iput(fs_info->btree_inode);
#if 0
@ -1171,12 +1355,18 @@ int btrfs_read_buffer(struct extent_buffer *buf)
{
struct btrfs_root *root = BTRFS_I(buf->first_page->mapping->host)->root;
struct inode *btree_inode = root->fs_info->btree_inode;
return read_extent_buffer_pages(&BTRFS_I(btree_inode)->io_tree,
int ret;
ret = read_extent_buffer_pages(&BTRFS_I(btree_inode)->io_tree,
buf, 0, 1, btree_get_extent);
if (ret == 0) {
buf->flags |= EXTENT_UPTODATE;
}
return ret;
}
static struct extent_io_ops btree_extent_io_ops = {
.writepage_io_hook = btree_writepage_io_hook,
.readpage_end_io_hook = btree_readpage_end_io_hook,
.submit_bio_hook = btree_submit_bio_hook,
/* note we're sharing with inode.c for the merge bio hook */
.merge_bio_hook = btrfs_merge_bio_hook,

4
fs/btrfs/extent-tree.c
View File

@ -1898,10 +1898,6 @@ struct extent_buffer *__btrfs_alloc_free_block(struct btrfs_trans_handle *trans,
set_extent_dirty(&trans->transaction->dirty_pages, buf->start,
buf->start + buf->len - 1, GFP_NOFS);
set_extent_bits(&BTRFS_I(root->fs_info->btree_inode)->io_tree,
buf->start, buf->start + buf->len - 1,
EXTENT_CSUM, GFP_NOFS);
buf->flags |= EXTENT_CSUM;
if (!btrfs_test_opt(root, SSD))
btrfs_set_buffer_defrag(buf);
trans->blocks_used++;

100
fs/btrfs/extent_io.c
View File

@ -2592,6 +2592,22 @@ static inline struct page *extent_buffer_page(struct extent_buffer *eb,
return p;
}
int release_extent_buffer_tail_pages(struct extent_buffer *eb)
{
unsigned long num_pages = num_extent_pages(eb->start, eb->len);
struct page *page;
unsigned long i;
if (num_pages == 1)
return 0;
for (i = 1; i < num_pages; i++) {
page = extent_buffer_page(eb, i);
page_cache_release(page);
}
return 0;
}
int invalidate_extent_lru(struct extent_io_tree *tree, u64 start,
unsigned long len)
{
@ -2609,9 +2625,6 @@ int invalidate_extent_lru(struct extent_io_tree *tree, u64 start,
if (eb->start <= start && eb->start + eb->len > start) {
eb->flags &= ~EXTENT_UPTODATE;
}
if (eb->start == start) {
eb->flags &= ~EXTENT_CSUM;
}
cur = cur->next;
} while (cur != lru);
out:
@ -2682,7 +2695,6 @@ struct extent_buffer *alloc_extent_buffer(struct extent_io_tree *tree,
page_cache_get(page0);
mark_page_accessed(page0);
set_page_extent_mapped(page0);
WARN_ON(!PageUptodate(page0));
set_page_extent_head(page0, len);
} else {
i = 0;
@ -2933,13 +2945,39 @@ int set_extent_buffer_uptodate(struct extent_io_tree *tree,
}
EXPORT_SYMBOL(set_extent_buffer_uptodate);
int extent_range_uptodate(struct extent_io_tree *tree,
u64 start, u64 end)
{
struct page *page;
int ret;
int pg_uptodate = 1;
int uptodate;
unsigned long index;
ret = test_range_bit(tree, start, end, EXTENT_UPTODATE, 1);
if (ret)
return 1;
while(start <= end) {
index = start >> PAGE_CACHE_SHIFT;
page = find_get_page(tree->mapping, index);
uptodate = PageUptodate(page);
page_cache_release(page);
if (!uptodate) {
pg_uptodate = 0;
break;
}
start += PAGE_CACHE_SIZE;
}
return pg_uptodate;
}
int extent_buffer_uptodate(struct extent_io_tree *tree,
struct extent_buffer *eb)
struct extent_buffer *eb)
{
int ret = 0;
int ret2;
int num_pages;
int i;
unsigned long num_pages;
unsigned long i;
struct page *page;
int pg_uptodate = 1;
@ -2975,13 +3013,16 @@ int read_extent_buffer_pages(struct extent_io_tree *tree,
struct page *page;
int err;
int ret = 0;
int locked_pages = 0;
int all_uptodate = 1;
int inc_all_pages = 0;
unsigned long num_pages;
struct bio *bio = NULL;
if (eb->flags & EXTENT_UPTODATE)
return 0;
if (0 && test_range_bit(tree, eb->start, eb->start + eb->len - 1,
if (test_range_bit(tree, eb->start, eb->start + eb->len - 1,
EXTENT_UPTODATE, 1)) {
return 0;
}
@ -2997,17 +3038,30 @@ int read_extent_buffer_pages(struct extent_io_tree *tree,
num_pages = num_extent_pages(eb->start, eb->len);
for (i = start_i; i < num_pages; i++) {
page = extent_buffer_page(eb, i);
if (PageUptodate(page)) {
continue;
}
if (!wait) {
if (TestSetPageLocked(page)) {
continue;
}
if (TestSetPageLocked(page))
goto unlock_exit;
} else {
lock_page(page);
}
locked_pages++;
if (!PageUptodate(page)) {
all_uptodate = 0;
}
}
if (all_uptodate) {
if (start_i == 0)
eb->flags |= EXTENT_UPTODATE;
goto unlock_exit;
}
for (i = start_i; i < num_pages; i++) {
page = extent_buffer_page(eb, i);
if (inc_all_pages)
page_cache_get(page);
if (!PageUptodate(page)) {
if (start_i == 0)
inc_all_pages = 1;
err = __extent_read_full_page(tree, page,
get_extent, &bio);
if (err) {
@ -3034,6 +3088,16 @@ int read_extent_buffer_pages(struct extent_io_tree *tree,
if (!ret)
eb->flags |= EXTENT_UPTODATE;
return ret;
unlock_exit:
i = start_i;
while(locked_pages > 0) {
page = extent_buffer_page(eb, i);
i++;
unlock_page(page);
locked_pages--;
}
return ret;
}
EXPORT_SYMBOL(read_extent_buffer_pages);
@ -3048,7 +3112,6 @@ void read_extent_buffer(struct extent_buffer *eb, void *dstv,
char *dst = (char *)dstv;
size_t start_offset = eb->start & ((u64)PAGE_CACHE_SIZE - 1);
unsigned long i = (start_offset + start) >> PAGE_CACHE_SHIFT;
unsigned long num_pages = num_extent_pages(eb->start, eb->len);
WARN_ON(start > eb->len);
WARN_ON(start + len > eb->start + eb->len);
@ -3057,11 +3120,6 @@ void read_extent_buffer(struct extent_buffer *eb, void *dstv,
while(len > 0) {
page = extent_buffer_page(eb, i);
if (!PageUptodate(page)) {
printk("page %lu not up to date i %lu, total %lu, len %lu\n", page->index, i, num_pages, eb->len);
WARN_ON(1);
}
WARN_ON(!PageUptodate(page));
cur = min(len, (PAGE_CACHE_SIZE - offset));
kaddr = kmap_atomic(page, KM_USER1);
@ -3105,7 +3163,6 @@ printk("bad mapping eb start %Lu len %lu, wanted %lu %lu\n", eb->start, eb->len,
}
p = extent_buffer_page(eb, i);
WARN_ON(!PageUptodate(p));
kaddr = kmap_atomic(p, km);
*token = kaddr;
*map = kaddr + offset;
@ -3165,7 +3222,6 @@ int memcmp_extent_buffer(struct extent_buffer *eb, const void *ptrv,
while(len > 0) {
page = extent_buffer_page(eb, i);
WARN_ON(!PageUptodate(page));
cur = min(len, (PAGE_CACHE_SIZE - offset));

4
fs/btrfs/extent_io.h
View File

@ -13,7 +13,6 @@
#define EXTENT_DEFRAG (1 << 6)
#define EXTENT_DEFRAG_DONE (1 << 7)
#define EXTENT_BUFFER_FILLED (1 << 8)
#define EXTENT_CSUM (1 << 9)
#define EXTENT_IOBITS (EXTENT_LOCKED | EXTENT_WRITEBACK)
/*
@ -218,4 +217,7 @@ int map_private_extent_buffer(struct extent_buffer *eb, unsigned long offset,
void unmap_extent_buffer(struct extent_buffer *eb, char *token, int km);
int invalidate_extent_lru(struct extent_io_tree *tree, u64 start,
unsigned long len);
int release_extent_buffer_tail_pages(struct extent_buffer *eb);
int extent_range_uptodate(struct extent_io_tree *tree,
u64 start, u64 end);
#endif

2
fs/btrfs/transaction.c
View File

@ -843,7 +843,7 @@ void btrfs_transaction_flush_work(struct btrfs_root *root)
void __init btrfs_init_transaction_sys(void)
{
trans_wq = create_workqueue("btrfs");
trans_wq = create_workqueue("btrfs-transaction");
}
void btrfs_exit_transaction_sys(void)