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Merge branch 'for-chris' of git://github.com/sensille/linux into integration 

Conflicts:
	fs/btrfs/ctree.h

Signed-off-by: Chris Mason <chris.mason@oracle.com>
This commit is contained in:
Chris Mason 2011-11-06 03:05:08 -05:00
parent c06a0e120a 7a26285eea
commit 531f4b1ae5
10 changed files with 1128 additions and 68 deletions
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3
fs/btrfs/Makefile
View File

@ -7,6 +7,7 @@ btrfs-y += super.o ctree.o extent-tree.o print-tree.o root-tree.o dir-item.o \
extent_map.o sysfs.o struct-funcs.o xattr.o ordered-data.o \
extent_io.o volumes.o async-thread.o ioctl.o locking.o orphan.o \
export.o tree-log.o free-space-cache.o zlib.o lzo.o \
compression.o delayed-ref.o relocation.o delayed-inode.o scrub.o
compression.o delayed-ref.o relocation.o delayed-inode.o scrub.o \
reada.o
btrfs-$(CONFIG_BTRFS_FS_POSIX_ACL) += acl.o

21
fs/btrfs/ctree.h
View File

@ -1074,6 +1074,7 @@ struct btrfs_fs_info {
struct btrfs_workers endio_freespace_worker;
struct btrfs_workers submit_workers;
struct btrfs_workers caching_workers;
struct btrfs_workers readahead_workers;
/*
* fixup workers take dirty pages that didn't properly go through
@ -1158,6 +1159,10 @@ struct btrfs_fs_info {
struct btrfs_delayed_root *delayed_root;
/* readahead tree */
spinlock_t reada_lock;
struct radix_tree_root reada_tree;
/* next backup root to be overwritten */
int backup_root_index;
};
@ -2812,4 +2817,20 @@ int btrfs_scrub_cancel_devid(struct btrfs_root *root, u64 devid);
int btrfs_scrub_progress(struct btrfs_root *root, u64 devid,
struct btrfs_scrub_progress *progress);
/* reada.c */
struct reada_control {
struct btrfs_root *root; /* tree to prefetch */
struct btrfs_key key_start;
struct btrfs_key key_end; /* exclusive */
atomic_t elems;
struct kref refcnt;
wait_queue_head_t wait;
};
struct reada_control *btrfs_reada_add(struct btrfs_root *root,
struct btrfs_key *start, struct btrfs_key *end);
int btrfs_reada_wait(void *handle);
void btrfs_reada_detach(void *handle);
int btree_readahead_hook(struct btrfs_root *root, struct extent_buffer *eb,
u64 start, int err);
#endif

84
fs/btrfs/disk-io.c
View File

@ -366,7 +366,8 @@ static int btree_read_extent_buffer_pages(struct btrfs_root *root,
clear_bit(EXTENT_BUFFER_CORRUPT, &eb->bflags);
io_tree = &BTRFS_I(root->fs_info->btree_inode)->io_tree;
while (1) {
ret = read_extent_buffer_pages(io_tree, eb, start, 1,
ret = read_extent_buffer_pages(io_tree, eb, start,
WAIT_COMPLETE,
btree_get_extent, mirror_num);
if (!ret &&
!verify_parent_transid(io_tree, eb, parent_transid))
@ -607,11 +608,47 @@ static int btree_readpage_end_io_hook(struct page *page, u64 start, u64 end,
end = min_t(u64, eb->len, PAGE_CACHE_SIZE);
end = eb->start + end - 1;
err:
if (test_bit(EXTENT_BUFFER_READAHEAD, &eb->bflags)) {
clear_bit(EXTENT_BUFFER_READAHEAD, &eb->bflags);
btree_readahead_hook(root, eb, eb->start, ret);
}
free_extent_buffer(eb);
out:
return ret;
}
static int btree_io_failed_hook(struct bio *failed_bio,
struct page *page, u64 start, u64 end,
struct extent_state *state)
{
struct extent_io_tree *tree;
unsigned long len;
struct extent_buffer *eb;
struct btrfs_root *root = BTRFS_I(page->mapping->host)->root;
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;
WARN_ON(len == 0);
eb = alloc_extent_buffer(tree, start, len, page);
if (eb == NULL)
goto out;
if (test_bit(EXTENT_BUFFER_READAHEAD, &eb->bflags)) {
clear_bit(EXTENT_BUFFER_READAHEAD, &eb->bflags);
btree_readahead_hook(root, eb, eb->start, -EIO);
}
out:
return -EIO; /* we fixed nothing */
}
static void end_workqueue_bio(struct bio *bio, int err)
{
struct end_io_wq *end_io_wq = bio->bi_private;
@ -973,11 +1010,43 @@ int readahead_tree_block(struct btrfs_root *root, u64 bytenr, u32 blocksize,
if (!buf)
return 0;
read_extent_buffer_pages(&BTRFS_I(btree_inode)->io_tree,
buf, 0, 0, btree_get_extent, 0);
buf, 0, WAIT_NONE, btree_get_extent, 0);
free_extent_buffer(buf);
return ret;
}
int reada_tree_block_flagged(struct btrfs_root *root, u64 bytenr, u32 blocksize,
int mirror_num, struct extent_buffer **eb)
{
struct extent_buffer *buf = NULL;
struct inode *btree_inode = root->fs_info->btree_inode;
struct extent_io_tree *io_tree = &BTRFS_I(btree_inode)->io_tree;
int ret;
buf = btrfs_find_create_tree_block(root, bytenr, blocksize);
if (!buf)
return 0;
set_bit(EXTENT_BUFFER_READAHEAD, &buf->bflags);
ret = read_extent_buffer_pages(io_tree, buf, 0, WAIT_PAGE_LOCK,
btree_get_extent, mirror_num);
if (ret) {
free_extent_buffer(buf);
return ret;
}
if (test_bit(EXTENT_BUFFER_CORRUPT, &buf->bflags)) {
free_extent_buffer(buf);
return -EIO;
} else if (extent_buffer_uptodate(io_tree, buf, NULL)) {
*eb = buf;
} else {
free_extent_buffer(buf);
}
return 0;
}
struct extent_buffer *btrfs_find_tree_block(struct btrfs_root *root,
u64 bytenr, u32 blocksize)
{
@ -1904,6 +1973,10 @@ struct btrfs_root *open_ctree(struct super_block *sb,
fs_info->trans_no_join = 0;
fs_info->free_chunk_space = 0;
/* readahead state */
INIT_RADIX_TREE(&fs_info->reada_tree, GFP_NOFS & ~__GFP_WAIT);
spin_lock_init(&fs_info->reada_lock);
fs_info->thread_pool_size = min_t(unsigned long,
num_online_cpus() + 2, 8);
@ -2103,6 +2176,9 @@ struct btrfs_root *open_ctree(struct super_block *sb,
btrfs_init_workers(&fs_info->delayed_workers, "delayed-meta",
fs_info->thread_pool_size,
&fs_info->generic_worker);
btrfs_init_workers(&fs_info->readahead_workers, "readahead",
fs_info->thread_pool_size,
&fs_info->generic_worker);
/*
* endios are largely parallel and should have a very
@ -2113,6 +2189,7 @@ struct btrfs_root *open_ctree(struct super_block *sb,
fs_info->endio_write_workers.idle_thresh = 2;
fs_info->endio_meta_write_workers.idle_thresh = 2;
fs_info->readahead_workers.idle_thresh = 2;
btrfs_start_workers(&fs_info->workers, 1);
btrfs_start_workers(&fs_info->generic_worker, 1);
@ -2126,6 +2203,7 @@ struct btrfs_root *open_ctree(struct super_block *sb,
btrfs_start_workers(&fs_info->endio_freespace_worker, 1);
btrfs_start_workers(&fs_info->delayed_workers, 1);
btrfs_start_workers(&fs_info->caching_workers, 1);
btrfs_start_workers(&fs_info->readahead_workers, 1);
fs_info->bdi.ra_pages *= btrfs_super_num_devices(disk_super);
fs_info->bdi.ra_pages = max(fs_info->bdi.ra_pages,
@ -2855,6 +2933,7 @@ int close_ctree(struct btrfs_root *root)
btrfs_stop_workers(&fs_info->submit_workers);
btrfs_stop_workers(&fs_info->delayed_workers);
btrfs_stop_workers(&fs_info->caching_workers);
btrfs_stop_workers(&fs_info->readahead_workers);
btrfs_close_devices(fs_info->fs_devices);
btrfs_mapping_tree_free(&fs_info->mapping_tree);
@ -3363,6 +3442,7 @@ static int btrfs_cleanup_transaction(struct btrfs_root *root)
static struct extent_io_ops btree_extent_io_ops = {
.write_cache_pages_lock_hook = btree_lock_page_hook,
.readpage_end_io_hook = btree_readpage_end_io_hook,
.readpage_io_failed_hook = btree_io_failed_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,

2
fs/btrfs/disk-io.h
View File

@ -40,6 +40,8 @@ struct extent_buffer *read_tree_block(struct btrfs_root *root, u64 bytenr,
u32 blocksize, u64 parent_transid);
int readahead_tree_block(struct btrfs_root *root, u64 bytenr, u32 blocksize,
u64 parent_transid);
int reada_tree_block_flagged(struct btrfs_root *root, u64 bytenr, u32 blocksize,
int mirror_num, struct extent_buffer **eb);
struct extent_buffer *btrfs_find_create_tree_block(struct btrfs_root *root,
u64 bytenr, u32 blocksize);
int clean_tree_block(struct btrfs_trans_handle *trans,

9
fs/btrfs/extent_io.c
View File

@ -1919,7 +1919,7 @@ static void end_bio_extent_readpage(struct bio *bio, int err)
if (!uptodate && tree->ops &&
tree->ops->readpage_io_failed_hook) {
ret = tree->ops->readpage_io_failed_hook(bio, page,
start, end, NULL);
start, end, state);
if (ret == 0) {
uptodate =
test_bit(BIO_UPTODATE, &bio->bi_flags);
@ -3551,8 +3551,7 @@ int extent_buffer_uptodate(struct extent_io_tree *tree,
}
int read_extent_buffer_pages(struct extent_io_tree *tree,
struct extent_buffer *eb,
u64 start, int wait,
struct extent_buffer *eb, u64 start, int wait,
get_extent_t *get_extent, int mirror_num)
{
unsigned long i;
@ -3588,7 +3587,7 @@ 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 (!wait) {
if (wait == WAIT_NONE) {
if (!trylock_page(page))
goto unlock_exit;
} else {
@ -3632,7 +3631,7 @@ int read_extent_buffer_pages(struct extent_io_tree *tree,
if (bio)
submit_one_bio(READ, bio, mirror_num, bio_flags);
if (ret || !wait)
if (ret || wait != WAIT_COMPLETE)
return ret;
for (i = start_i; i < num_pages; i++) {

4
fs/btrfs/extent_io.h
View File

@ -33,6 +33,7 @@
#define EXTENT_BUFFER_BLOCKING 1
#define EXTENT_BUFFER_DIRTY 2
#define EXTENT_BUFFER_CORRUPT 3
#define EXTENT_BUFFER_READAHEAD 4 /* this got triggered by readahead */
/* these are flags for extent_clear_unlock_delalloc */
#define EXTENT_CLEAR_UNLOCK_PAGE 0x1
@ -252,6 +253,9 @@ struct extent_buffer *alloc_extent_buffer(struct extent_io_tree *tree,
struct extent_buffer *find_extent_buffer(struct extent_io_tree *tree,
u64 start, unsigned long len);
void free_extent_buffer(struct extent_buffer *eb);
#define WAIT_NONE 0
#define WAIT_COMPLETE 1
#define WAIT_PAGE_LOCK 2
int read_extent_buffer_pages(struct extent_io_tree *tree,
struct extent_buffer *eb, u64 start, int wait,
get_extent_t *get_extent, int mirror_num);

949
fs/btrfs/reada.c Normal file
View File

@ -0,0 +1,949 @@
/*
* Copyright (C) 2011 STRATO. All rights reserved.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public
* License v2 as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public
* License along with this program; if not, write to the
* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
* Boston, MA 021110-1307, USA.
*/
#include <linux/sched.h>
#include <linux/pagemap.h>
#include <linux/writeback.h>
#include <linux/blkdev.h>
#include <linux/rbtree.h>
#include <linux/slab.h>
#include <linux/workqueue.h>
#include "ctree.h"
#include "volumes.h"
#include "disk-io.h"
#include "transaction.h"
#undef DEBUG
/*
* This is the implementation for the generic read ahead framework.
*
* To trigger a readahead, btrfs_reada_add must be called. It will start
* a read ahead for the given range [start, end) on tree root. The returned
* handle can either be used to wait on the readahead to finish
* (btrfs_reada_wait), or to send it to the background (btrfs_reada_detach).
*
* The read ahead works as follows:
* On btrfs_reada_add, the root of the tree is inserted into a radix_tree.
* reada_start_machine will then search for extents to prefetch and trigger
* some reads. When a read finishes for a node, all contained node/leaf
* pointers that lie in the given range will also be enqueued. The reads will
* be triggered in sequential order, thus giving a big win over a naive
* enumeration. It will also make use of multi-device layouts. Each disk
* will have its on read pointer and all disks will by utilized in parallel.
* Also will no two disks read both sides of a mirror simultaneously, as this
* would waste seeking capacity. Instead both disks will read different parts
* of the filesystem.
* Any number of readaheads can be started in parallel. The read order will be
* determined globally, i.e. 2 parallel readaheads will normally finish faster
* than the 2 started one after another.
*/
#define MAX_MIRRORS 2
#define MAX_IN_FLIGHT 6
struct reada_extctl {
struct list_head list;
struct reada_control *rc;
u64 generation;
};
struct reada_extent {
u64 logical;
struct btrfs_key top;
u32 blocksize;
int err;
struct list_head extctl;
struct kref refcnt;
spinlock_t lock;
struct reada_zone *zones[MAX_MIRRORS];
int nzones;
struct btrfs_device *scheduled_for;
};
struct reada_zone {
u64 start;
u64 end;
u64 elems;
struct list_head list;
spinlock_t lock;
int locked;
struct btrfs_device *device;
struct btrfs_device *devs[MAX_MIRRORS]; /* full list, incl self */
int ndevs;
struct kref refcnt;
};
struct reada_machine_work {
struct btrfs_work work;
struct btrfs_fs_info *fs_info;
};
static void reada_extent_put(struct btrfs_fs_info *, struct reada_extent *);
static void reada_control_release(struct kref *kref);
static void reada_zone_release(struct kref *kref);
static void reada_start_machine(struct btrfs_fs_info *fs_info);
static void __reada_start_machine(struct btrfs_fs_info *fs_info);
static int reada_add_block(struct reada_control *rc, u64 logical,
struct btrfs_key *top, int level, u64 generation);
/* recurses */
/* in case of err, eb might be NULL */
static int __readahead_hook(struct btrfs_root *root, struct extent_buffer *eb,
u64 start, int err)
{
int level = 0;
int nritems;
int i;
u64 bytenr;
u64 generation;
struct reada_extent *re;
struct btrfs_fs_info *fs_info = root->fs_info;
struct list_head list;
unsigned long index = start >> PAGE_CACHE_SHIFT;
struct btrfs_device *for_dev;
if (eb)
level = btrfs_header_level(eb);
/* find extent */
spin_lock(&fs_info->reada_lock);
re = radix_tree_lookup(&fs_info->reada_tree, index);
if (re)
kref_get(&re->refcnt);
spin_unlock(&fs_info->reada_lock);
if (!re)
return -1;
spin_lock(&re->lock);
/*
* just take the full list from the extent. afterwards we
* don't need the lock anymore
*/
list_replace_init(&re->extctl, &list);
for_dev = re->scheduled_for;
re->scheduled_for = NULL;
spin_unlock(&re->lock);
if (err == 0) {
nritems = level ? btrfs_header_nritems(eb) : 0;
generation = btrfs_header_generation(eb);
/*
* FIXME: currently we just set nritems to 0 if this is a leaf,
* effectively ignoring the content. In a next step we could
* trigger more readahead depending from the content, e.g.
* fetch the checksums for the extents in the leaf.
*/
} else {
/*
* this is the error case, the extent buffer has not been
* read correctly. We won't access anything from it and
* just cleanup our data structures. Effectively this will
* cut the branch below this node from read ahead.
*/
nritems = 0;
generation = 0;
}
for (i = 0; i < nritems; i++) {
struct reada_extctl *rec;
u64 n_gen;
struct btrfs_key key;
struct btrfs_key next_key;
btrfs_node_key_to_cpu(eb, &key, i);
if (i + 1 < nritems)
btrfs_node_key_to_cpu(eb, &next_key, i + 1);
else
next_key = re->top;
bytenr = btrfs_node_blockptr(eb, i);
n_gen = btrfs_node_ptr_generation(eb, i);
list_for_each_entry(rec, &list, list) {
struct reada_control *rc = rec->rc;
/*
* if the generation doesn't match, just ignore this
* extctl. This will probably cut off a branch from
* prefetch. Alternatively one could start a new (sub-)
* prefetch for this branch, starting again from root.
* FIXME: move the generation check out of this loop
*/
#ifdef DEBUG
if (rec->generation != generation) {
printk(KERN_DEBUG "generation mismatch for "
"(%llu,%d,%llu) %llu != %llu\n",
key.objectid, key.type, key.offset,
rec->generation, generation);
}
#endif
if (rec->generation == generation &&
btrfs_comp_cpu_keys(&key, &rc->key_end) < 0 &&
btrfs_comp_cpu_keys(&next_key, &rc->key_start) > 0)
reada_add_block(rc, bytenr, &next_key,
level - 1, n_gen);
}
}
/*
* free extctl records
*/
while (!list_empty(&list)) {
struct reada_control *rc;
struct reada_extctl *rec;
rec = list_first_entry(&list, struct reada_extctl, list);
list_del(&rec->list);
rc = rec->rc;
kfree(rec);
kref_get(&rc->refcnt);
if (atomic_dec_and_test(&rc->elems)) {
kref_put(&rc->refcnt, reada_control_release);
wake_up(&rc->wait);
}
kref_put(&rc->refcnt, reada_control_release);
reada_extent_put(fs_info, re); /* one ref for each entry */
}
reada_extent_put(fs_info, re); /* our ref */
if (for_dev)
atomic_dec(&for_dev->reada_in_flight);
return 0;
}
/*
* start is passed separately in case eb in NULL, which may be the case with
* failed I/O
*/
int btree_readahead_hook(struct btrfs_root *root, struct extent_buffer *eb,
u64 start, int err)
{
int ret;
ret = __readahead_hook(root, eb, start, err);
reada_start_machine(root->fs_info);
return ret;
}
static struct reada_zone *reada_find_zone(struct btrfs_fs_info *fs_info,
struct btrfs_device *dev, u64 logical,
struct btrfs_multi_bio *multi)
{
int ret;
int looped = 0;
struct reada_zone *zone;
struct btrfs_block_group_cache *cache = NULL;
u64 start;
u64 end;
int i;
again:
zone = NULL;
spin_lock(&fs_info->reada_lock);
ret = radix_tree_gang_lookup(&dev->reada_zones, (void **)&zone,
logical >> PAGE_CACHE_SHIFT, 1);
if (ret == 1)
kref_get(&zone->refcnt);
spin_unlock(&fs_info->reada_lock);
if (ret == 1) {
if (logical >= zone->start && logical < zone->end)
return zone;
spin_lock(&fs_info->reada_lock);
kref_put(&zone->refcnt, reada_zone_release);
spin_unlock(&fs_info->reada_lock);
}
if (looped)
return NULL;
cache = btrfs_lookup_block_group(fs_info, logical);
if (!cache)
return NULL;
start = cache->key.objectid;
end = start + cache->key.offset - 1;
btrfs_put_block_group(cache);
zone = kzalloc(sizeof(*zone), GFP_NOFS);
if (!zone)
return NULL;
zone->start = start;
zone->end = end;
INIT_LIST_HEAD(&zone->list);
spin_lock_init(&zone->lock);
zone->locked = 0;
kref_init(&zone->refcnt);
zone->elems = 0;
zone->device = dev; /* our device always sits at index 0 */
for (i = 0; i < multi->num_stripes; ++i) {
/* bounds have already been checked */
zone->devs[i] = multi->stripes[i].dev;
}
zone->ndevs = multi->num_stripes;
spin_lock(&fs_info->reada_lock);
ret = radix_tree_insert(&dev->reada_zones,
(unsigned long)zone->end >> PAGE_CACHE_SHIFT,
zone);
spin_unlock(&fs_info->reada_lock);
if (ret) {
kfree(zone);
looped = 1;
goto again;
}
return zone;
}
static struct reada_extent *reada_find_extent(struct btrfs_root *root,
u64 logical,
struct btrfs_key *top, int level)
{
int ret;
int looped = 0;
struct reada_extent *re = NULL;
struct btrfs_fs_info *fs_info = root->fs_info;
struct btrfs_mapping_tree *map_tree = &fs_info->mapping_tree;
struct btrfs_multi_bio *multi = NULL;
struct btrfs_device *dev;
u32 blocksize;
u64 length;
int nzones = 0;
int i;
unsigned long index = logical >> PAGE_CACHE_SHIFT;
again:
spin_lock(&fs_info->reada_lock);
re = radix_tree_lookup(&fs_info->reada_tree, index);
if (re)
kref_get(&re->refcnt);
spin_unlock(&fs_info->reada_lock);
if (re || looped)
return re;
re = kzalloc(sizeof(*re), GFP_NOFS);
if (!re)
return NULL;
blocksize = btrfs_level_size(root, level);
re->logical = logical;
re->blocksize = blocksize;
re->top = *top;
INIT_LIST_HEAD(&re->extctl);
spin_lock_init(&re->lock);
kref_init(&re->refcnt);
/*
* map block
*/
length = blocksize;
ret = btrfs_map_block(map_tree, REQ_WRITE, logical, &length, &multi, 0);
if (ret || !multi || length < blocksize)
goto error;
if (multi->num_stripes > MAX_MIRRORS) {
printk(KERN_ERR "btrfs readahead: more than %d copies not "
"supported", MAX_MIRRORS);
goto error;
}
for (nzones = 0; nzones < multi->num_stripes; ++nzones) {
struct reada_zone *zone;
dev = multi->stripes[nzones].dev;
zone = reada_find_zone(fs_info, dev, logical, multi);
if (!zone)
break;
re->zones[nzones] = zone;
spin_lock(&zone->lock);
if (!zone->elems)
kref_get(&zone->refcnt);
++zone->elems;
spin_unlock(&zone->lock);
spin_lock(&fs_info->reada_lock);
kref_put(&zone->refcnt, reada_zone_release);
spin_unlock(&fs_info->reada_lock);
}
re->nzones = nzones;
if (nzones == 0) {
/* not a single zone found, error and out */
goto error;
}
/* insert extent in reada_tree + all per-device trees, all or nothing */
spin_lock(&fs_info->reada_lock);
ret = radix_tree_insert(&fs_info->reada_tree, index, re);
if (ret) {
spin_unlock(&fs_info->reada_lock);
if (ret != -ENOMEM) {
/* someone inserted the extent in the meantime */
looped = 1;
}
goto error;
}
for (i = 0; i < nzones; ++i) {
dev = multi->stripes[i].dev;
ret = radix_tree_insert(&dev->reada_extents, index, re);
if (ret) {
while (--i >= 0) {
dev = multi->stripes[i].dev;
BUG_ON(dev == NULL);
radix_tree_delete(&dev->reada_extents, index);
}
BUG_ON(fs_info == NULL);
radix_tree_delete(&fs_info->reada_tree, index);
spin_unlock(&fs_info->reada_lock);
goto error;
}
}
spin_unlock(&fs_info->reada_lock);
return re;
error:
while (nzones) {
struct reada_zone *zone;
--nzones;
zone = re->zones[nzones];
kref_get(&zone->refcnt);
spin_lock(&zone->lock);
--zone->elems;
if (zone->elems == 0) {
/*
* no fs_info->reada_lock needed, as this can't be
* the last ref
*/
kref_put(&zone->refcnt, reada_zone_release);
}
spin_unlock(&zone->lock);
spin_lock(&fs_info->reada_lock);
kref_put(&zone->refcnt, reada_zone_release);
spin_unlock(&fs_info->reada_lock);
}
kfree(re);
if (looped)
goto again;
return NULL;
}
static void reada_kref_dummy(struct kref *kr)
{
}
static void reada_extent_put(struct btrfs_fs_info *fs_info,
struct reada_extent *re)
{
int i;
unsigned long index = re->logical >> PAGE_CACHE_SHIFT;
spin_lock(&fs_info->reada_lock);
if (!kref_put(&re->refcnt, reada_kref_dummy)) {
spin_unlock(&fs_info->reada_lock);
return;
}
radix_tree_delete(&fs_info->reada_tree, index);
for (i = 0; i < re->nzones; ++i) {
struct reada_zone *zone = re->zones[i];
radix_tree_delete(&zone->device->reada_extents, index);
}
spin_unlock(&fs_info->reada_lock);
for (i = 0; i < re->nzones; ++i) {
struct reada_zone *zone = re->zones[i];
kref_get(&zone->refcnt);
spin_lock(&zone->lock);
--zone->elems;
if (zone->elems == 0) {
/* no fs_info->reada_lock needed, as this can't be
* the last ref */
kref_put(&zone->refcnt, reada_zone_release);
}
spin_unlock(&zone->lock);
spin_lock(&fs_info->reada_lock);
kref_put(&zone->refcnt, reada_zone_release);
spin_unlock(&fs_info->reada_lock);
}
if (re->scheduled_for)
atomic_dec(&re->scheduled_for->reada_in_flight);
kfree(re);
}
static void reada_zone_release(struct kref *kref)
{
struct reada_zone *zone = container_of(kref, struct reada_zone, refcnt);
radix_tree_delete(&zone->device->reada_zones,
zone->end >> PAGE_CACHE_SHIFT);
kfree(zone);
}
static void reada_control_release(struct kref *kref)
{
struct reada_control *rc = container_of(kref, struct reada_control,
refcnt);
kfree(rc);
}
static int reada_add_block(struct reada_control *rc, u64 logical,
struct btrfs_key *top, int level, u64 generation)
{
struct btrfs_root *root = rc->root;
struct reada_extent *re;
struct reada_extctl *rec;
re = reada_find_extent(root, logical, top, level); /* takes one ref */
if (!re)
return -1;
rec = kzalloc(sizeof(*rec), GFP_NOFS);
if (!rec) {
reada_extent_put(root->fs_info, re);
return -1;
}
rec->rc = rc;
rec->generation = generation;
atomic_inc(&rc->elems);
spin_lock(&re->lock);
list_add_tail(&rec->list, &re->extctl);
spin_unlock(&re->lock);
/* leave the ref on the extent */
return 0;
}
/*
* called with fs_info->reada_lock held
*/
static void reada_peer_zones_set_lock(struct reada_zone *zone, int lock)
{
int i;
unsigned long index = zone->end >> PAGE_CACHE_SHIFT;
for (i = 0; i < zone->ndevs; ++i) {
struct reada_zone *peer;
peer = radix_tree_lookup(&zone->devs[i]->reada_zones, index);
if (peer && peer->device != zone->device)
peer->locked = lock;
}
}
/*
* called with fs_info->reada_lock held
*/
static int reada_pick_zone(struct btrfs_device *dev)
{
struct reada_zone *top_zone = NULL;
struct reada_zone *top_locked_zone = NULL;
u64 top_elems = 0;
u64 top_locked_elems = 0;
unsigned long index = 0;
int ret;
if (dev->reada_curr_zone) {
reada_peer_zones_set_lock(dev->reada_curr_zone, 0);
kref_put(&dev->reada_curr_zone->refcnt, reada_zone_release);
dev->reada_curr_zone = NULL;
}
/* pick the zone with the most elements */
while (1) {
struct reada_zone *zone;
ret = radix_tree_gang_lookup(&dev->reada_zones,
(void **)&zone, index, 1);
if (ret == 0)
break;
index = (zone->end >> PAGE_CACHE_SHIFT) + 1;
if (zone->locked) {
if (zone->elems > top_locked_elems) {
top_locked_elems = zone->elems;
top_locked_zone = zone;
}
} else {
if (zone->elems > top_elems) {
top_elems = zone->elems;
top_zone = zone;
}
}
}
if (top_zone)
dev->reada_curr_zone = top_zone;
else if (top_locked_zone)
dev->reada_curr_zone = top_locked_zone;
else
return 0;
dev->reada_next = dev->reada_curr_zone->start;
kref_get(&dev->reada_curr_zone->refcnt);
reada_peer_zones_set_lock(dev->reada_curr_zone, 1);
return 1;
}
static int reada_start_machine_dev(struct btrfs_fs_info *fs_info,
struct btrfs_device *dev)
{
struct reada_extent *re = NULL;
int mirror_num = 0;
struct extent_buffer *eb = NULL;
u64 logical;
u32 blocksize;
int ret;
int i;
int need_kick = 0;
spin_lock(&fs_info->reada_lock);
if (dev->reada_curr_zone == NULL) {
ret = reada_pick_zone(dev);
if (!ret) {
spin_unlock(&fs_info->reada_lock);
return 0;
}
}
/*
* FIXME currently we issue the reads one extent at a time. If we have
* a contiguous block of extents, we could also coagulate them or use
* plugging to speed things up
*/
ret = radix_tree_gang_lookup(&dev->reada_extents, (void **)&re,
dev->reada_next >> PAGE_CACHE_SHIFT, 1);
if (ret == 0 || re->logical >= dev->reada_curr_zone->end) {
ret = reada_pick_zone(dev);
if (!ret) {
spin_unlock(&fs_info->reada_lock);
return 0;
}
re = NULL;
ret = radix_tree_gang_lookup(&dev->reada_extents, (void **)&re,
dev->reada_next >> PAGE_CACHE_SHIFT, 1);
}
if (ret == 0) {
spin_unlock(&fs_info->reada_lock);
return 0;
}
dev->reada_next = re->logical + re->blocksize;
kref_get(&re->refcnt);
spin_unlock(&fs_info->reada_lock);
/*
* find mirror num
*/
for (i = 0; i < re->nzones; ++i) {
if (re->zones[i]->device == dev) {
mirror_num = i + 1;
break;
}
}
logical = re->logical;
blocksize = re->blocksize;
spin_lock(&re->lock);
if (re->scheduled_for == NULL) {
re->scheduled_for = dev;
need_kick = 1;
}
spin_unlock(&re->lock);
reada_extent_put(fs_info, re);
if (!need_kick)
return 0;
atomic_inc(&dev->reada_in_flight);
ret = reada_tree_block_flagged(fs_info->extent_root, logical, blocksize,
mirror_num, &eb);
if (ret)
__readahead_hook(fs_info->extent_root, NULL, logical, ret);
else if (eb)
__readahead_hook(fs_info->extent_root, eb, eb->start, ret);
if (eb)
free_extent_buffer(eb);
return 1;
}
static void reada_start_machine_worker(struct btrfs_work *work)
{
struct reada_machine_work *rmw;
struct btrfs_fs_info *fs_info;
rmw = container_of(work, struct reada_machine_work, work);
fs_info = rmw->fs_info;
kfree(rmw);
__reada_start_machine(fs_info);
}
static void __reada_start_machine(struct btrfs_fs_info *fs_info)
{
struct btrfs_device *device;
struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
u64 enqueued;
u64 total = 0;
int i;
do {
enqueued = 0;
list_for_each_entry(device, &fs_devices->devices, dev_list) {
if (atomic_read(&device->reada_in_flight) <
MAX_IN_FLIGHT)
enqueued += reada_start_machine_dev(fs_info,
device);
}
total += enqueued;
} while (enqueued && total < 10000);
if (enqueued == 0)
return;
/*
* If everything is already in the cache, this is effectively single
* threaded. To a) not hold the caller for too long and b) to utilize
* more cores, we broke the loop above after 10000 iterations and now
* enqueue to workers to finish it. This will distribute the load to
* the cores.
*/
for (i = 0; i < 2; ++i)
reada_start_machine(fs_info);
}
static void reada_start_machine(struct btrfs_fs_info *fs_info)
{
struct reada_machine_work *rmw;
rmw = kzalloc(sizeof(*rmw), GFP_NOFS);
if (!rmw) {
/* FIXME we cannot handle this properly right now */
BUG();
}
rmw->work.func = reada_start_machine_worker;
rmw->fs_info = fs_info;
btrfs_queue_worker(&fs_info->readahead_workers, &rmw->work);
}
#ifdef DEBUG
static void dump_devs(struct btrfs_fs_info *fs_info, int all)
{
struct btrfs_device *device;
struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
unsigned long index;
int ret;
int i;
int j;
int cnt;
spin_lock(&fs_info->reada_lock);
list_for_each_entry(device, &fs_devices->devices, dev_list) {
printk(KERN_DEBUG "dev %lld has %d in flight\n", device->devid,
atomic_read(&device->reada_in_flight));
index = 0;
while (1) {
struct reada_zone *zone;
ret = radix_tree_gang_lookup(&device->reada_zones,
(void **)&zone, index, 1);
if (ret == 0)
break;
printk(KERN_DEBUG " zone %llu-%llu elems %llu locked "
"%d devs", zone->start, zone->end, zone->elems,
zone->locked);
for (j = 0; j < zone->ndevs; ++j) {
printk(KERN_CONT " %lld",
zone->devs[j]->devid);
}
if (device->reada_curr_zone == zone)
printk(KERN_CONT " curr off %llu",
device->reada_next - zone->start);
printk(KERN_CONT "\n");
index = (zone->end >> PAGE_CACHE_SHIFT) + 1;
}
cnt = 0;
index = 0;
while (all) {
struct reada_extent *re = NULL;
ret = radix_tree_gang_lookup(&device->reada_extents,
(void **)&re, index, 1);
if (ret == 0)
break;
printk(KERN_DEBUG
" re: logical %llu size %u empty %d for %lld",
re->logical, re->blocksize,
list_empty(&re->extctl), re->scheduled_for ?
re->scheduled_for->devid : -1);
for (i = 0; i < re->nzones; ++i) {
printk(KERN_CONT " zone %llu-%llu devs",
re->zones[i]->start,
re->zones[i]->end);
for (j = 0; j < re->zones[i]->ndevs; ++j) {
printk(KERN_CONT " %lld",
re->zones[i]->devs[j]->devid);
}
}
printk(KERN_CONT "\n");
index = (re->logical >> PAGE_CACHE_SHIFT) + 1;
if (++cnt > 15)
break;
}
}
index = 0;
cnt = 0;
while (all) {
struct reada_extent *re = NULL;
ret = radix_tree_gang_lookup(&fs_info->reada_tree, (void **)&re,
index, 1);
if (ret == 0)
break;
if (!re->scheduled_for) {
index = (re->logical >> PAGE_CACHE_SHIFT) + 1;
continue;
}
printk(KERN_DEBUG
"re: logical %llu size %u list empty %d for %lld",
re->logical, re->blocksize, list_empty(&re->extctl),
re->scheduled_for ? re->scheduled_for->devid : -1);
for (i = 0; i < re->nzones; ++i) {
printk(KERN_CONT " zone %llu-%llu devs",
re->zones[i]->start,
re->zones[i]->end);
for (i = 0; i < re->nzones; ++i) {
printk(KERN_CONT " zone %llu-%llu devs",
re->zones[i]->start,
re->zones[i]->end);
for (j = 0; j < re->zones[i]->ndevs; ++j) {
printk(KERN_CONT " %lld",
re->zones[i]->devs[j]->devid);
}
}
}
printk(KERN_CONT "\n");
index = (re->logical >> PAGE_CACHE_SHIFT) + 1;
}
spin_unlock(&fs_info->reada_lock);
}
#endif
/*
* interface
*/
struct reada_control *btrfs_reada_add(struct btrfs_root *root,
struct btrfs_key *key_start, struct btrfs_key *key_end)
{
struct reada_control *rc;
u64 start;
u64 generation;
int level;
struct extent_buffer *node;
static struct btrfs_key max_key = {
.objectid = (u64)-1,
.type = (u8)-1,
.offset = (u64)-1
};
rc = kzalloc(sizeof(*rc), GFP_NOFS);
if (!rc)
return ERR_PTR(-ENOMEM);
rc->root = root;
rc->key_start = *key_start;
rc->key_end = *key_end;
atomic_set(&rc->elems, 0);
init_waitqueue_head(&rc->wait);
kref_init(&rc->refcnt);
kref_get(&rc->refcnt); /* one ref for having elements */
node = btrfs_root_node(root);
start = node->start;
level = btrfs_header_level(node);
generation = btrfs_header_generation(node);
free_extent_buffer(node);
reada_add_block(rc, start, &max_key, level, generation);
reada_start_machine(root->fs_info);
return rc;
}
#ifdef DEBUG
int btrfs_reada_wait(void *handle)
{
struct reada_control *rc = handle;
while (atomic_read(&rc->elems)) {
wait_event_timeout(rc->wait, atomic_read(&rc->elems) == 0,
5 * HZ);
dump_devs(rc->root->fs_info, rc->elems < 10 ? 1 : 0);
}
dump_devs(rc->root->fs_info, rc->elems < 10 ? 1 : 0);
kref_put(&rc->refcnt, reada_control_release);
return 0;
}
#else
int btrfs_reada_wait(void *handle)
{
struct reada_control *rc = handle;
while (atomic_read(&rc->elems)) {
wait_event(rc->wait, atomic_read(&rc->elems) == 0);
}
kref_put(&rc->refcnt, reada_control_release);
return 0;
}
#endif
void btrfs_reada_detach(void *handle)
{
struct reada_control *rc = handle;
kref_put(&rc->refcnt, reada_control_release);
}

108
fs/btrfs/scrub.c
View File

@ -29,15 +29,12 @@
* any can be found.
*
* Future enhancements:
* - To enhance the performance, better read-ahead strategies for the
* extent-tree can be employed.
* - In case an unrepairable extent is encountered, track which files are
* affected and report them
* - In case of a read error on files with nodatasum, map the file and read
* the extent to trigger a writeback of the good copy
* - track and record media errors, throw out bad devices
* - add a mode to also read unallocated space
* - make the prefetch cancellable
*/
struct scrub_bio;
@ -741,13 +738,16 @@ static noinline_for_stack int scrub_stripe(struct scrub_dev *sdev,
int slot;
int i;
u64 nstripes;
int start_stripe;
struct extent_buffer *l;
struct btrfs_key key;
u64 physical;
u64 logical;
u64 generation;
u64 mirror_num;
struct reada_control *reada1;
struct reada_control *reada2;
struct btrfs_key key_start;
struct btrfs_key key_end;
u64 increment = map->stripe_len;
u64 offset;
@ -779,81 +779,67 @@ static noinline_for_stack int scrub_stripe(struct scrub_dev *sdev,
if (!path)
return -ENOMEM;
path->reada = 2;
path->search_commit_root = 1;
path->skip_locking = 1;
/*
* find all extents for each stripe and just read them to get
* them into the page cache
* FIXME: we can do better. build a more intelligent prefetching
* trigger the readahead for extent tree csum tree and wait for
* completion. During readahead, the scrub is officially paused
* to not hold off transaction commits
*/
logical = base + offset;
physical = map->stripes[num].physical;
ret = 0;
for (i = 0; i < nstripes; ++i) {
key.objectid = logical;
key.type = BTRFS_EXTENT_ITEM_KEY;
key.offset = (u64)0;
ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
if (ret < 0)
goto out_noplug;
wait_event(sdev->list_wait,
atomic_read(&sdev->in_flight) == 0);
atomic_inc(&fs_info->scrubs_paused);
wake_up(&fs_info->scrub_pause_wait);
/*
* we might miss half an extent here, but that doesn't matter,
* as it's only the prefetch
*/
while (1) {
l = path->nodes[0];
slot = path->slots[0];
if (slot >= btrfs_header_nritems(l)) {
ret = btrfs_next_leaf(root, path);
if (ret == 0)
continue;
if (ret < 0)
goto out_noplug;
/* FIXME it might be better to start readahead at commit root */
key_start.objectid = logical;
key_start.type = BTRFS_EXTENT_ITEM_KEY;
key_start.offset = (u64)0;
key_end.objectid = base + offset + nstripes * increment;
key_end.type = BTRFS_EXTENT_ITEM_KEY;
key_end.offset = (u64)0;
reada1 = btrfs_reada_add(root, &key_start, &key_end);
break;
}
btrfs_item_key_to_cpu(l, &key, slot);
key_start.objectid = BTRFS_EXTENT_CSUM_OBJECTID;
key_start.type = BTRFS_EXTENT_CSUM_KEY;
key_start.offset = logical;
key_end.objectid = BTRFS_EXTENT_CSUM_OBJECTID;
key_end.type = BTRFS_EXTENT_CSUM_KEY;
key_end.offset = base + offset + nstripes * increment;
reada2 = btrfs_reada_add(csum_root, &key_start, &key_end);
if (key.objectid >= logical + map->stripe_len)
break;
if (!IS_ERR(reada1))
btrfs_reada_wait(reada1);
if (!IS_ERR(reada2))
btrfs_reada_wait(reada2);
path->slots[0]++;
}
btrfs_release_path(path);
logical += increment;
physical += map->stripe_len;
cond_resched();
mutex_lock(&fs_info->scrub_lock);
while (atomic_read(&fs_info->scrub_pause_req)) {
mutex_unlock(&fs_info->scrub_lock);
wait_event(fs_info->scrub_pause_wait,
atomic_read(&fs_info->scrub_pause_req) == 0);
mutex_lock(&fs_info->scrub_lock);
}
atomic_dec(&fs_info->scrubs_paused);
mutex_unlock(&fs_info->scrub_lock);
wake_up(&fs_info->scrub_pause_wait);
/*
* collect all data csums for the stripe to avoid seeking during
* the scrub. This might currently (crc32) end up to be about 1MB
*/
start_stripe = 0;
blk_start_plug(&plug);
again:
logical = base + offset + start_stripe * increment;
for (i = start_stripe; i < nstripes; ++i) {
ret = btrfs_lookup_csums_range(csum_root, logical,
logical + map->stripe_len - 1,
&sdev->csum_list, 1);
if (ret)
goto out;
logical += increment;
cond_resched();
}
/*
* now find all extents for each stripe and scrub them
*/
logical = base + offset + start_stripe * increment;
physical = map->stripes[num].physical + start_stripe * map->stripe_len;
logical = base + offset;
physical = map->stripes[num].physical;
ret = 0;
for (i = start_stripe; i < nstripes; ++i) {
for (i = 0; i < nstripes; ++i) {
/*
* canceled?
*/
@ -882,11 +868,14 @@ again:
atomic_dec(&fs_info->scrubs_paused);
mutex_unlock(&fs_info->scrub_lock);
wake_up(&fs_info->scrub_pause_wait);
scrub_free_csums(sdev);
start_stripe = i;
goto again;
}
ret = btrfs_lookup_csums_range(csum_root, logical,
logical + map->stripe_len - 1,
&sdev->csum_list, 1);
if (ret)
goto out;
key.objectid = logical;
key.type = BTRFS_EXTENT_ITEM_KEY;
key.offset = (u64)0;
@ -982,7 +971,6 @@ next:
out:
blk_finish_plug(&plug);
out_noplug:
btrfs_free_path(path);
return ret < 0 ? ret : 0;
}

8
fs/btrfs/volumes.c
View File

@ -366,6 +366,14 @@ static noinline int device_list_add(const char *path,
}
INIT_LIST_HEAD(&device->dev_alloc_list);
/* init readahead state */
spin_lock_init(&device->reada_lock);
device->reada_curr_zone = NULL;
atomic_set(&device->reada_in_flight, 0);
device->reada_next = 0;
INIT_RADIX_TREE(&device->reada_zones, GFP_NOFS & ~__GFP_WAIT);
INIT_RADIX_TREE(&device->reada_extents, GFP_NOFS & ~__GFP_WAIT);
mutex_lock(&fs_devices->device_list_mutex);
list_add_rcu(&device->dev_list, &fs_devices->devices);
mutex_unlock(&fs_devices->device_list_mutex);

8
fs/btrfs/volumes.h
View File

@ -92,6 +92,14 @@ struct btrfs_device {
struct btrfs_work work;
struct rcu_head rcu;
struct work_struct rcu_work;
/* readahead state */
spinlock_t reada_lock;
atomic_t reada_in_flight;
u64 reada_next;
struct reada_zone *reada_curr_zone;
struct radix_tree_root reada_zones;
struct radix_tree_root reada_extents;
};
struct btrfs_fs_devices {