btrfs-progs/extent_io.c
Jeff Mahoney a5ce5d2198 btrfs-progs: extent-cache: actually cache extent buffers
We have the infrastructure to cache extent buffers but we don't actually
do the caching.  As soon as the last reference is dropped, the buffer
is dropped.  This patch keeps the extent buffers around until the max
cache size is reached (defaults to 25% of memory) and then it drops
the last 10% of the LRU to free up cache space for reallocation.  The
cache size is configurable (for use by e.g. lowmem) when the cache is
initialized.

Signed-off-by: Jeff Mahoney <jeffm@suse.com>
[ update codingstyle, switch total_memory to bytes ]
Signed-off-by: David Sterba <dsterba@suse.com>
2017-10-06 13:41:06 +02:00

943 lines
21 KiB
C

/*
* Copyright (C) 2007 Oracle. 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 <stdio.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#include <stdbool.h>
#include "kerncompat.h"
#include "extent_io.h"
#include "list.h"
#include "ctree.h"
#include "volumes.h"
#include "utils.h"
#include "internal.h"
void extent_io_tree_init(struct extent_io_tree *tree)
{
cache_tree_init(&tree->state);
cache_tree_init(&tree->cache);
INIT_LIST_HEAD(&tree->lru);
tree->cache_size = 0;
tree->max_cache_size = (u64)total_memory() / 4;
}
void extent_io_tree_init_cache_max(struct extent_io_tree *tree,
u64 max_cache_size)
{
extent_io_tree_init(tree);
tree->max_cache_size = max_cache_size;
}
static struct extent_state *alloc_extent_state(void)
{
struct extent_state *state;
state = malloc(sizeof(*state));
if (!state)
return NULL;
state->cache_node.objectid = 0;
state->refs = 1;
state->state = 0;
state->xprivate = 0;
return state;
}
static void btrfs_free_extent_state(struct extent_state *state)
{
state->refs--;
BUG_ON(state->refs < 0);
if (state->refs == 0)
free(state);
}
static void free_extent_state_func(struct cache_extent *cache)
{
struct extent_state *es;
es = container_of(cache, struct extent_state, cache_node);
btrfs_free_extent_state(es);
}
static void free_extent_buffer_final(struct extent_buffer *eb);
void extent_io_tree_cleanup(struct extent_io_tree *tree)
{
struct extent_buffer *eb;
while(!list_empty(&tree->lru)) {
eb = list_entry(tree->lru.next, struct extent_buffer, lru);
if (eb->refs) {
fprintf(stderr,
"extent buffer leak: start %llu len %u\n",
(unsigned long long)eb->start, eb->len);
free_extent_buffer_nocache(eb);
} else {
free_extent_buffer_final(eb);
}
}
cache_tree_free_extents(&tree->state, free_extent_state_func);
}
static inline void update_extent_state(struct extent_state *state)
{
state->cache_node.start = state->start;
state->cache_node.size = state->end + 1 - state->start;
}
/*
* Utility function to look for merge candidates inside a given range.
* Any extents with matching state are merged together into a single
* extent in the tree. Extents with EXTENT_IO in their state field are
* not merged
*/
static int merge_state(struct extent_io_tree *tree,
struct extent_state *state)
{
struct extent_state *other;
struct cache_extent *other_node;
if (state->state & EXTENT_IOBITS)
return 0;
other_node = prev_cache_extent(&state->cache_node);
if (other_node) {
other = container_of(other_node, struct extent_state,
cache_node);
if (other->end == state->start - 1 &&
other->state == state->state) {
state->start = other->start;
update_extent_state(state);
remove_cache_extent(&tree->state, &other->cache_node);
btrfs_free_extent_state(other);
}
}
other_node = next_cache_extent(&state->cache_node);
if (other_node) {
other = container_of(other_node, struct extent_state,
cache_node);
if (other->start == state->end + 1 &&
other->state == state->state) {
other->start = state->start;
update_extent_state(other);
remove_cache_extent(&tree->state, &state->cache_node);
btrfs_free_extent_state(state);
}
}
return 0;
}
/*
* insert an extent_state struct into the tree. 'bits' are set on the
* struct before it is inserted.
*/
static int insert_state(struct extent_io_tree *tree,
struct extent_state *state, u64 start, u64 end,
int bits)
{
int ret;
BUG_ON(end < start);
state->state |= bits;
state->start = start;
state->end = end;
update_extent_state(state);
ret = insert_cache_extent(&tree->state, &state->cache_node);
BUG_ON(ret);
merge_state(tree, state);
return 0;
}
/*
* split a given extent state struct in two, inserting the preallocated
* struct 'prealloc' as the newly created second half. 'split' indicates an
* offset inside 'orig' where it should be split.
*/
static int split_state(struct extent_io_tree *tree, struct extent_state *orig,
struct extent_state *prealloc, u64 split)
{
int ret;
prealloc->start = orig->start;
prealloc->end = split - 1;
prealloc->state = orig->state;
update_extent_state(prealloc);
orig->start = split;
update_extent_state(orig);
ret = insert_cache_extent(&tree->state, &prealloc->cache_node);
BUG_ON(ret);
return 0;
}
/*
* clear some bits on a range in the tree.
*/
static int clear_state_bit(struct extent_io_tree *tree,
struct extent_state *state, int bits)
{
int ret = state->state & bits;
state->state &= ~bits;
if (state->state == 0) {
remove_cache_extent(&tree->state, &state->cache_node);
btrfs_free_extent_state(state);
} else {
merge_state(tree, state);
}
return ret;
}
/*
* clear some bits on a range in the tree.
*/
int clear_extent_bits(struct extent_io_tree *tree, u64 start, u64 end, int bits)
{
struct extent_state *state;
struct extent_state *prealloc = NULL;
struct cache_extent *node;
u64 last_end;
int err;
int set = 0;
again:
if (!prealloc) {
prealloc = alloc_extent_state();
if (!prealloc)
return -ENOMEM;
}
/*
* this search will find the extents that end after
* our range starts
*/
node = search_cache_extent(&tree->state, start);
if (!node)
goto out;
state = container_of(node, struct extent_state, cache_node);
if (state->start > end)
goto out;
last_end = state->end;
/*
* | ---- desired range ---- |
* | state | or
* | ------------- state -------------- |
*
* We need to split the extent we found, and may flip
* bits on second half.
*
* If the extent we found extends past our range, we
* just split and search again. It'll get split again
* the next time though.
*
* If the extent we found is inside our range, we clear
* the desired bit on it.
*/
if (state->start < start) {
err = split_state(tree, state, prealloc, start);
BUG_ON(err == -EEXIST);
prealloc = NULL;
if (err)
goto out;
if (state->end <= end) {
set |= clear_state_bit(tree, state, bits);
if (last_end == (u64)-1)
goto out;
start = last_end + 1;
} else {
start = state->start;
}
goto search_again;
}
/*
* | ---- desired range ---- |
* | state |
* We need to split the extent, and clear the bit
* on the first half
*/
if (state->start <= end && state->end > end) {
err = split_state(tree, state, prealloc, end + 1);
BUG_ON(err == -EEXIST);
set |= clear_state_bit(tree, prealloc, bits);
prealloc = NULL;
goto out;
}
start = state->end + 1;
set |= clear_state_bit(tree, state, bits);
if (last_end == (u64)-1)
goto out;
start = last_end + 1;
goto search_again;
out:
if (prealloc)
btrfs_free_extent_state(prealloc);
return set;
search_again:
if (start > end)
goto out;
goto again;
}
/*
* set some bits on a range in the tree.
*/
int set_extent_bits(struct extent_io_tree *tree, u64 start, u64 end, int bits)
{
struct extent_state *state;
struct extent_state *prealloc = NULL;
struct cache_extent *node;
int err = 0;
u64 last_start;
u64 last_end;
again:
if (!prealloc) {
prealloc = alloc_extent_state();
if (!prealloc)
return -ENOMEM;
}
/*
* this search will find the extents that end after
* our range starts
*/
node = search_cache_extent(&tree->state, start);
if (!node) {
err = insert_state(tree, prealloc, start, end, bits);
BUG_ON(err == -EEXIST);
prealloc = NULL;
goto out;
}
state = container_of(node, struct extent_state, cache_node);
last_start = state->start;
last_end = state->end;
/*
* | ---- desired range ---- |
* | state |
*
* Just lock what we found and keep going
*/
if (state->start == start && state->end <= end) {
state->state |= bits;
merge_state(tree, state);
if (last_end == (u64)-1)
goto out;
start = last_end + 1;
goto search_again;
}
/*
* | ---- desired range ---- |
* | state |
* or
* | ------------- state -------------- |
*
* We need to split the extent we found, and may flip bits on
* second half.
*
* If the extent we found extends past our
* range, we just split and search again. It'll get split
* again the next time though.
*
* If the extent we found is inside our range, we set the
* desired bit on it.
*/
if (state->start < start) {
err = split_state(tree, state, prealloc, start);
BUG_ON(err == -EEXIST);
prealloc = NULL;
if (err)
goto out;
if (state->end <= end) {
state->state |= bits;
start = state->end + 1;
merge_state(tree, state);
if (last_end == (u64)-1)
goto out;
start = last_end + 1;
} else {
start = state->start;
}
goto search_again;
}
/*
* | ---- desired range ---- |
* | state | or | state |
*
* There's a hole, we need to insert something in it and
* ignore the extent we found.
*/
if (state->start > start) {
u64 this_end;
if (end < last_start)
this_end = end;
else
this_end = last_start -1;
err = insert_state(tree, prealloc, start, this_end,
bits);
BUG_ON(err == -EEXIST);
prealloc = NULL;
if (err)
goto out;
start = this_end + 1;
goto search_again;
}
/*
* | ---- desired range ---- |
* | ---------- state ---------- |
* We need to split the extent, and set the bit
* on the first half
*/
err = split_state(tree, state, prealloc, end + 1);
BUG_ON(err == -EEXIST);
state->state |= bits;
merge_state(tree, prealloc);
prealloc = NULL;
out:
if (prealloc)
btrfs_free_extent_state(prealloc);
return err;
search_again:
if (start > end)
goto out;
goto again;
}
int set_extent_dirty(struct extent_io_tree *tree, u64 start, u64 end)
{
return set_extent_bits(tree, start, end, EXTENT_DIRTY);
}
int clear_extent_dirty(struct extent_io_tree *tree, u64 start, u64 end)
{
return clear_extent_bits(tree, start, end, EXTENT_DIRTY);
}
int find_first_extent_bit(struct extent_io_tree *tree, u64 start,
u64 *start_ret, u64 *end_ret, int bits)
{
struct cache_extent *node;
struct extent_state *state;
int ret = 1;
/*
* this search will find all the extents that end after
* our range starts.
*/
node = search_cache_extent(&tree->state, start);
if (!node)
goto out;
while(1) {
state = container_of(node, struct extent_state, cache_node);
if (state->end >= start && (state->state & bits)) {
*start_ret = state->start;
*end_ret = state->end;
ret = 0;
break;
}
node = next_cache_extent(node);
if (!node)
break;
}
out:
return ret;
}
int test_range_bit(struct extent_io_tree *tree, u64 start, u64 end,
int bits, int filled)
{
struct extent_state *state = NULL;
struct cache_extent *node;
int bitset = 0;
node = search_cache_extent(&tree->state, start);
while (node && start <= end) {
state = container_of(node, struct extent_state, cache_node);
if (filled && state->start > start) {
bitset = 0;
break;
}
if (state->start > end)
break;
if (state->state & bits) {
bitset = 1;
if (!filled)
break;
} else if (filled) {
bitset = 0;
break;
}
start = state->end + 1;
if (start > end)
break;
node = next_cache_extent(node);
if (!node) {
if (filled)
bitset = 0;
break;
}
}
return bitset;
}
int set_state_private(struct extent_io_tree *tree, u64 start, u64 private)
{
struct cache_extent *node;
struct extent_state *state;
int ret = 0;
node = search_cache_extent(&tree->state, start);
if (!node) {
ret = -ENOENT;
goto out;
}
state = container_of(node, struct extent_state, cache_node);
if (state->start != start) {
ret = -ENOENT;
goto out;
}
state->xprivate = private;
out:
return ret;
}
int get_state_private(struct extent_io_tree *tree, u64 start, u64 *private)
{
struct cache_extent *node;
struct extent_state *state;
int ret = 0;
node = search_cache_extent(&tree->state, start);
if (!node) {
ret = -ENOENT;
goto out;
}
state = container_of(node, struct extent_state, cache_node);
if (state->start != start) {
ret = -ENOENT;
goto out;
}
*private = state->xprivate;
out:
return ret;
}
static struct extent_buffer *__alloc_extent_buffer(struct extent_io_tree *tree,
u64 bytenr, u32 blocksize)
{
struct extent_buffer *eb;
eb = calloc(1, sizeof(struct extent_buffer) + blocksize);
if (!eb)
return NULL;
eb->start = bytenr;
eb->len = blocksize;
eb->refs = 1;
eb->flags = 0;
eb->tree = tree;
eb->fd = -1;
eb->dev_bytenr = (u64)-1;
eb->cache_node.start = bytenr;
eb->cache_node.size = blocksize;
INIT_LIST_HEAD(&eb->recow);
return eb;
}
struct extent_buffer *btrfs_clone_extent_buffer(struct extent_buffer *src)
{
struct extent_buffer *new;
new = __alloc_extent_buffer(NULL, src->start, src->len);
if (!new)
return NULL;
copy_extent_buffer(new, src, 0, 0, src->len);
new->flags |= EXTENT_BUFFER_DUMMY;
return new;
}
static void free_extent_buffer_final(struct extent_buffer *eb)
{
struct extent_io_tree *tree = eb->tree;
BUG_ON(eb->refs);
BUG_ON(tree->cache_size < eb->len);
list_del_init(&eb->lru);
if (!(eb->flags & EXTENT_BUFFER_DUMMY)) {
remove_cache_extent(&tree->cache, &eb->cache_node);
tree->cache_size -= eb->len;
}
free(eb);
}
static void free_extent_buffer_internal(struct extent_buffer *eb, bool free_now)
{
if (!eb || IS_ERR(eb))
return;
eb->refs--;
BUG_ON(eb->refs < 0);
if (eb->refs == 0) {
BUG_ON(eb->flags & EXTENT_DIRTY);
list_del_init(&eb->recow);
if (eb->flags & EXTENT_BUFFER_DUMMY || free_now)
free_extent_buffer_final(eb);
}
}
void free_extent_buffer(struct extent_buffer *eb)
{
free_extent_buffer_internal(eb, 0);
}
void free_extent_buffer_nocache(struct extent_buffer *eb)
{
free_extent_buffer_internal(eb, 1);
}
struct extent_buffer *find_extent_buffer(struct extent_io_tree *tree,
u64 bytenr, u32 blocksize)
{
struct extent_buffer *eb = NULL;
struct cache_extent *cache;
cache = lookup_cache_extent(&tree->cache, bytenr, blocksize);
if (cache && cache->start == bytenr &&
cache->size == blocksize) {
eb = container_of(cache, struct extent_buffer, cache_node);
list_move_tail(&eb->lru, &tree->lru);
eb->refs++;
}
return eb;
}
struct extent_buffer *find_first_extent_buffer(struct extent_io_tree *tree,
u64 start)
{
struct extent_buffer *eb = NULL;
struct cache_extent *cache;
cache = search_cache_extent(&tree->cache, start);
if (cache) {
eb = container_of(cache, struct extent_buffer, cache_node);
list_move_tail(&eb->lru, &tree->lru);
eb->refs++;
}
return eb;
}
static void trim_extent_buffer_cache(struct extent_io_tree *tree)
{
struct extent_buffer *eb, *tmp;
list_for_each_entry_safe(eb, tmp, &tree->lru, lru) {
if (eb->refs == 0)
free_extent_buffer_final(eb);
if (tree->cache_size <= ((tree->max_cache_size * 9) / 10))
break;
}
}
struct extent_buffer *alloc_extent_buffer(struct extent_io_tree *tree,
u64 bytenr, u32 blocksize)
{
struct extent_buffer *eb;
struct cache_extent *cache;
cache = lookup_cache_extent(&tree->cache, bytenr, blocksize);
if (cache && cache->start == bytenr &&
cache->size == blocksize) {
eb = container_of(cache, struct extent_buffer, cache_node);
list_move_tail(&eb->lru, &tree->lru);
eb->refs++;
} else {
int ret;
if (cache) {
eb = container_of(cache, struct extent_buffer,
cache_node);
free_extent_buffer(eb);
}
eb = __alloc_extent_buffer(tree, bytenr, blocksize);
if (!eb)
return NULL;
ret = insert_cache_extent(&tree->cache, &eb->cache_node);
if (ret) {
free(eb);
return NULL;
}
list_add_tail(&eb->lru, &tree->lru);
tree->cache_size += blocksize;
if (tree->cache_size >= tree->max_cache_size)
trim_extent_buffer_cache(tree);
}
return eb;
}
int read_extent_from_disk(struct extent_buffer *eb,
unsigned long offset, unsigned long len)
{
int ret;
ret = pread(eb->fd, eb->data + offset, len, eb->dev_bytenr);
if (ret < 0) {
ret = -errno;
goto out;
}
if (ret != len) {
ret = -EIO;
goto out;
}
ret = 0;
out:
return ret;
}
int write_extent_to_disk(struct extent_buffer *eb)
{
int ret;
ret = pwrite(eb->fd, eb->data, eb->len, eb->dev_bytenr);
if (ret < 0)
goto out;
if (ret != eb->len) {
ret = -EIO;
goto out;
}
ret = 0;
out:
return ret;
}
int read_data_from_disk(struct btrfs_fs_info *info, void *buf, u64 offset,
u64 bytes, int mirror)
{
struct btrfs_multi_bio *multi = NULL;
struct btrfs_device *device;
u64 bytes_left = bytes;
u64 read_len;
u64 total_read = 0;
int ret;
while (bytes_left) {
read_len = bytes_left;
ret = btrfs_map_block(info, READ, offset, &read_len, &multi,
mirror, NULL);
if (ret) {
fprintf(stderr, "Couldn't map the block %Lu\n",
offset);
return -EIO;
}
device = multi->stripes[0].dev;
read_len = min(bytes_left, read_len);
if (device->fd <= 0) {
kfree(multi);
return -EIO;
}
ret = pread(device->fd, buf + total_read, read_len,
multi->stripes[0].physical);
kfree(multi);
if (ret < 0) {
fprintf(stderr, "Error reading %Lu, %d\n", offset,
ret);
return ret;
}
if (ret != read_len) {
fprintf(stderr, "Short read for %Lu, read %d, "
"read_len %Lu\n", offset, ret, read_len);
return -EIO;
}
bytes_left -= read_len;
offset += read_len;
total_read += read_len;
}
return 0;
}
int write_data_to_disk(struct btrfs_fs_info *info, void *buf, u64 offset,
u64 bytes, int mirror)
{
struct btrfs_multi_bio *multi = NULL;
struct btrfs_device *device;
u64 bytes_left = bytes;
u64 this_len;
u64 total_write = 0;
u64 *raid_map = NULL;
u64 dev_bytenr;
int dev_nr;
int ret = 0;
while (bytes_left > 0) {
this_len = bytes_left;
dev_nr = 0;
ret = btrfs_map_block(info, WRITE, offset, &this_len, &multi,
mirror, &raid_map);
if (ret) {
fprintf(stderr, "Couldn't map the block %Lu\n",
offset);
return -EIO;
}
if (raid_map) {
struct extent_buffer *eb;
u64 stripe_len = this_len;
this_len = min(this_len, bytes_left);
this_len = min(this_len, (u64)info->nodesize);
eb = malloc(sizeof(struct extent_buffer) + this_len);
if (!eb) {
fprintf(stderr, "cannot allocate memory for eb\n");
ret = -ENOMEM;
goto out;
}
memset(eb, 0, sizeof(struct extent_buffer) + this_len);
eb->start = offset;
eb->len = this_len;
memcpy(eb->data, buf + total_write, this_len);
ret = write_raid56_with_parity(info, eb, multi,
stripe_len, raid_map);
BUG_ON(ret);
free(eb);
kfree(raid_map);
raid_map = NULL;
} else while (dev_nr < multi->num_stripes) {
device = multi->stripes[dev_nr].dev;
if (device->fd <= 0) {
kfree(multi);
return -EIO;
}
dev_bytenr = multi->stripes[dev_nr].physical;
this_len = min(this_len, bytes_left);
dev_nr++;
ret = pwrite(device->fd, buf + total_write, this_len, dev_bytenr);
if (ret != this_len) {
if (ret < 0) {
fprintf(stderr, "Error writing to "
"device %d\n", errno);
ret = errno;
kfree(multi);
return ret;
} else {
fprintf(stderr, "Short write\n");
kfree(multi);
return -EIO;
}
}
}
BUG_ON(bytes_left < this_len);
bytes_left -= this_len;
offset += this_len;
total_write += this_len;
kfree(multi);
multi = NULL;
}
return 0;
out:
kfree(raid_map);
return ret;
}
int set_extent_buffer_dirty(struct extent_buffer *eb)
{
struct extent_io_tree *tree = eb->tree;
if (!(eb->flags & EXTENT_DIRTY)) {
eb->flags |= EXTENT_DIRTY;
set_extent_dirty(tree, eb->start, eb->start + eb->len - 1);
extent_buffer_get(eb);
}
return 0;
}
int clear_extent_buffer_dirty(struct extent_buffer *eb)
{
struct extent_io_tree *tree = eb->tree;
if (eb->flags & EXTENT_DIRTY) {
eb->flags &= ~EXTENT_DIRTY;
clear_extent_dirty(tree, eb->start, eb->start + eb->len - 1);
free_extent_buffer(eb);
}
return 0;
}
int memcmp_extent_buffer(struct extent_buffer *eb, const void *ptrv,
unsigned long start, unsigned long len)
{
return memcmp(eb->data + start, ptrv, len);
}
void read_extent_buffer(struct extent_buffer *eb, void *dst,
unsigned long start, unsigned long len)
{
memcpy(dst, eb->data + start, len);
}
void write_extent_buffer(struct extent_buffer *eb, const void *src,
unsigned long start, unsigned long len)
{
memcpy(eb->data + start, src, len);
}
void copy_extent_buffer(struct extent_buffer *dst, struct extent_buffer *src,
unsigned long dst_offset, unsigned long src_offset,
unsigned long len)
{
memcpy(dst->data + dst_offset, src->data + src_offset, len);
}
void memmove_extent_buffer(struct extent_buffer *dst, unsigned long dst_offset,
unsigned long src_offset, unsigned long len)
{
memmove(dst->data + dst_offset, dst->data + src_offset, len);
}
void memset_extent_buffer(struct extent_buffer *eb, char c,
unsigned long start, unsigned long len)
{
memset(eb->data + start, c, len);
}
int extent_buffer_test_bit(struct extent_buffer *eb, unsigned long start,
unsigned long nr)
{
return le_test_bit(nr, (u8 *)eb->data + start);
}