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Commit a52d9a80 authored by Chris Mason's avatar Chris Mason Committed by David Woodhouse
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Btrfs: Extent based page cache code. This uses an rbtree of extents and tests 

instead of buffer heads.
Signed-off-by: default avatarChris Mason <chris.mason@oracle.com>
parent 83df7c1d
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Showing with 2203 additions and 669 deletions
fs/btrfs/Makefile
View file @ a52d9a80
......@@ -4,7 +4,8 @@ ifneq ($(KERNELRELEASE),)
obj-m := btrfs.o
btrfs-y := super.o ctree.o extent-tree.o print-tree.o root-tree.o dir-item.o \
hash.o file-item.o inode-item.o inode-map.o disk-io.o \
transaction.o bit-radix.o inode.o file.o tree-defrag.o
transaction.o bit-radix.o inode.o file.o tree-defrag.o \
extent_map.o
#btrfs-y := ctree.o disk-io.o radix-tree.o extent-tree.o print-tree.o \
# root-tree.o dir-item.o hash.o file-item.o inode-item.o \
......
fs/btrfs/btrfs_inode.h
View file @ a52d9a80
......@@ -19,11 +19,14 @@
#ifndef __BTRFS_I__
#define __BTRFS_I__
#include "extent_map.h"
/* in memory btrfs inode */
struct btrfs_inode {
struct btrfs_root *root;
struct btrfs_block_group_cache *block_group;
struct btrfs_key location;
struct extent_map_tree extent_tree;
struct inode vfs_inode;
/*
......
fs/btrfs/ctree.h
View file @ a52d9a80
......@@ -1176,7 +1176,14 @@ int btrfs_commit_write(struct file *file, struct page *page,
unsigned from, unsigned to);
int btrfs_get_block(struct inode *inode, sector_t iblock,
struct buffer_head *result, int create);
struct extent_map *btrfs_get_extent(struct inode *inode, struct page *page,
size_t page_offset, u64 start, u64 end,
int create);
int btrfs_update_inode(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
struct inode *inode);
/* file.c */
int btrfs_drop_extent_cache(struct inode *inode, u64 start, u64 end);
extern struct file_operations btrfs_file_operations;
int btrfs_drop_extents(struct btrfs_trans_handle *trans,
struct btrfs_root *root, struct inode *inode,
......
fs/btrfs/disk-io.h
View file @ a52d9a80
......@@ -77,7 +77,6 @@ int btrfs_insert_dev_radix(struct btrfs_root *root,
u64 num_blocks);
int btrfs_map_bh_to_logical(struct btrfs_root *root, struct buffer_head *bh,
u64 logical);
int btrfs_releasepage(struct page *page, gfp_t flags);
void btrfs_btree_balance_dirty(struct btrfs_root *root);
int btrfs_free_fs_root(struct btrfs_fs_info *fs_info, struct btrfs_root *root);
void btrfs_mark_buffer_dirty(struct buffer_head *bh);
......
fs/btrfs/extent_map.c 0 → 100644
View file @ a52d9a80
#include <linux/bitops.h>
#include <linux/slab.h>
#include <linux/bio.h>
#include <linux/mm.h>
#include <linux/gfp.h>
#include <linux/pagemap.h>
#include <linux/page-flags.h>
#include <linux/module.h>
#include <linux/spinlock.h>
#include <linux/blkdev.h>
#include "extent_map.h"
static struct kmem_cache *extent_map_cache;
static struct kmem_cache *extent_state_cache;
struct tree_entry {
u64 start;
u64 end;
int in_tree;
struct rb_node rb_node;
};
/* bits for the extent state */
#define EXTENT_DIRTY 1
#define EXTENT_WRITEBACK (1 << 1)
#define EXTENT_UPTODATE (1 << 2)
#define EXTENT_LOCKED (1 << 3)
#define EXTENT_NEW (1 << 4)
#define EXTENT_DELALLOC (1 << 5)
#define EXTENT_IOBITS (EXTENT_LOCKED | EXTENT_WRITEBACK)
static LIST_HEAD(all_states);
spinlock_t state_lock = SPIN_LOCK_UNLOCKED;
void __init extent_map_init(void)
{
extent_map_cache = kmem_cache_create("extent_map",
sizeof(struct extent_map), 0,
SLAB_RECLAIM_ACCOUNT |
SLAB_DESTROY_BY_RCU,
NULL);
extent_state_cache = kmem_cache_create("extent_state",
sizeof(struct extent_state), 0,
SLAB_RECLAIM_ACCOUNT |
SLAB_DESTROY_BY_RCU,
NULL);
}
void __exit extent_map_exit(void)
{
while(!list_empty(&all_states)) {
struct extent_state *state;
struct list_head *cur = all_states.next;
state = list_entry(cur, struct extent_state, list);
printk("found leaked state %Lu %Lu state %d in_tree %d\n",
state->start, state->end, state->state, state->in_tree);
list_del(&state->list);
kfree(state);
}
if (extent_map_cache)
kmem_cache_destroy(extent_map_cache);
if (extent_state_cache)
kmem_cache_destroy(extent_state_cache);
}
void extent_map_tree_init(struct extent_map_tree *tree,
struct address_space *mapping, gfp_t mask)
{
tree->map.rb_node = NULL;
tree->state.rb_node = NULL;
rwlock_init(&tree->lock);
tree->mapping = mapping;
}
EXPORT_SYMBOL(extent_map_tree_init);
struct extent_map *alloc_extent_map(gfp_t mask)
{
struct extent_map *em;
em = kmem_cache_alloc(extent_map_cache, mask);
if (!em || IS_ERR(em))
return em;
em->in_tree = 0;
atomic_set(&em->refs, 1);
return em;
}
EXPORT_SYMBOL(alloc_extent_map);
void free_extent_map(struct extent_map *em)
{
if (atomic_dec_and_test(&em->refs)) {
WARN_ON(em->in_tree);
kmem_cache_free(extent_map_cache, em);
}
}
EXPORT_SYMBOL(free_extent_map);
struct extent_state *alloc_extent_state(gfp_t mask)
{
struct extent_state *state;
state = kmem_cache_alloc(extent_state_cache, mask);
if (!state || IS_ERR(state))
return state;
state->state = 0;
state->in_tree = 0;
atomic_set(&state->refs, 1);
init_waitqueue_head(&state->wq);
spin_lock_irq(&state_lock);
list_add(&state->list, &all_states);
spin_unlock_irq(&state_lock);
return state;
}
EXPORT_SYMBOL(alloc_extent_state);
void free_extent_state(struct extent_state *state)
{
if (atomic_dec_and_test(&state->refs)) {
WARN_ON(state->in_tree);
spin_lock_irq(&state_lock);
list_del_init(&state->list);
spin_unlock_irq(&state_lock);
kmem_cache_free(extent_state_cache, state);
}
}
EXPORT_SYMBOL(free_extent_state);
static struct rb_node *tree_insert(struct rb_root *root, u64 offset,
struct rb_node *node)
{
struct rb_node ** p = &root->rb_node;
struct rb_node * parent = NULL;
struct tree_entry *entry;
while(*p) {
parent = *p;
entry = rb_entry(parent, struct tree_entry, rb_node);
if (offset < entry->start)
p = &(*p)->rb_left;
else if (offset > entry->end)
p = &(*p)->rb_right;
else
return parent;
}
entry = rb_entry(node, struct tree_entry, rb_node);
entry->in_tree = 1;
rb_link_node(node, parent, p);
rb_insert_color(node, root);
return NULL;
}
static struct rb_node *__tree_search(struct rb_root *root, u64 offset,
struct rb_node **prev_ret)
{
struct rb_node * n = root->rb_node;
struct rb_node *prev = NULL;
struct tree_entry *entry;
struct tree_entry *prev_entry = NULL;
while(n) {
entry = rb_entry(n, struct tree_entry, rb_node);
prev = n;
prev_entry = entry;
if (offset < entry->start)
n = n->rb_left;
else if (offset > entry->end)
n = n->rb_right;
else
return n;
}
if (!prev_ret)
return NULL;
while(prev && offset > prev_entry->end) {
prev = rb_next(prev);
prev_entry = rb_entry(prev, struct tree_entry, rb_node);
}
*prev_ret = prev;
return NULL;
}
static inline struct rb_node *tree_search(struct rb_root *root, u64 offset)
{
struct rb_node *prev;
struct rb_node *ret;
ret = __tree_search(root, offset, &prev);
if (!ret)
return prev;
return ret;
}
static int tree_delete(struct rb_root *root, u64 offset)
{
struct rb_node *node;
struct tree_entry *entry;
node = __tree_search(root, offset, NULL);
if (!node)
return -ENOENT;
entry = rb_entry(node, struct tree_entry, rb_node);
entry->in_tree = 0;
rb_erase(node, root);
return 0;
}
/*
* add_extent_mapping tries a simple backward merge with existing
* mappings. The extent_map struct passed in will be inserted into
* the tree directly (no copies made, just a reference taken).
*/
int add_extent_mapping(struct extent_map_tree *tree,
struct extent_map *em)
{
int ret = 0;
struct extent_map *prev = NULL;
struct rb_node *rb;
write_lock_irq(&tree->lock);
rb = tree_insert(&tree->map, em->end, &em->rb_node);
if (rb) {
prev = rb_entry(rb, struct extent_map, rb_node);
printk("found extent map %Lu %Lu on insert of %Lu %Lu\n", prev->start, prev->end, em->start, em->end);
ret = -EEXIST;
goto out;
}
atomic_inc(&em->refs);
if (em->start != 0) {
rb = rb_prev(&em->rb_node);
if (rb)
prev = rb_entry(rb, struct extent_map, rb_node);
if (prev && prev->end + 1 == em->start &&
((em->block_start == 0 && prev->block_start == 0) ||
(em->block_start == prev->block_end + 1))) {
em->start = prev->start;
em->block_start = prev->block_start;
rb_erase(&prev->rb_node, &tree->map);
prev->in_tree = 0;
free_extent_map(prev);
}
}
out:
write_unlock_irq(&tree->lock);
return ret;
}
EXPORT_SYMBOL(add_extent_mapping);
/*
* lookup_extent_mapping returns the first extent_map struct in the
* tree that intersects the [start, end] (inclusive) range. There may
* be additional objects in the tree that intersect, so check the object
* returned carefully to make sure you don't need additional lookups.
*/
struct extent_map *lookup_extent_mapping(struct extent_map_tree *tree,
u64 start, u64 end)
{
struct extent_map *em;
struct rb_node *rb_node;
read_lock_irq(&tree->lock);
rb_node = tree_search(&tree->map, start);
if (!rb_node) {
em = NULL;
goto out;
}
if (IS_ERR(rb_node)) {
em = ERR_PTR(PTR_ERR(rb_node));
goto out;
}
em = rb_entry(rb_node, struct extent_map, rb_node);
if (em->end < start || em->start > end) {
em = NULL;
goto out;
}
atomic_inc(&em->refs);
out:
read_unlock_irq(&tree->lock);
return em;
}
EXPORT_SYMBOL(lookup_extent_mapping);
/*
* removes an extent_map struct from the tree. No reference counts are
* dropped, and no checks are done to see if the range is in use
*/
int remove_extent_mapping(struct extent_map_tree *tree, struct extent_map *em)
{
int ret;
write_lock_irq(&tree->lock);
ret = tree_delete(&tree->map, em->end);
write_unlock_irq(&tree->lock);
return ret;
}
EXPORT_SYMBOL(remove_extent_mapping);
/*
* 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 because the end_io handlers need to be able to do
* operations on them without sleeping (or doing allocations/splits).
*
* This should be called with the tree lock held.
*/
static int merge_state(struct extent_map_tree *tree,
struct extent_state *state)
{
struct extent_state *other;
struct rb_node *other_node;
if (state->state & EXTENT_IOBITS)
return 0;
other_node = rb_prev(&state->rb_node);
if (other_node) {
other = rb_entry(other_node, struct extent_state, rb_node);
if (other->end == state->start - 1 &&
other->state == state->state) {
state->start = other->start;
other->in_tree = 0;
rb_erase(&other->rb_node, &tree->state);
free_extent_state(other);
}
}
other_node = rb_next(&state->rb_node);
if (other_node) {
other = rb_entry(other_node, struct extent_state, rb_node);
if (other->start == state->end + 1 &&
other->state == state->state) {
other->start = state->start;
state->in_tree = 0;
rb_erase(&state->rb_node, &tree->state);
free_extent_state(state);
}
}
return 0;
}
/*
* insert an extent_state struct into the tree. 'bits' are set on the
* struct before it is inserted.
*
* This may return -EEXIST if the extent is already there, in which case the
* state struct is freed.
*
* The tree lock is not taken internally. This is a utility function and
* probably isn't what you want to call (see set/clear_extent_bit).
*/
static int insert_state(struct extent_map_tree *tree,
struct extent_state *state, u64 start, u64 end,
int bits)
{
struct rb_node *node;
if (end < start) {
printk("end < start %Lu %Lu\n", end, start);
WARN_ON(1);
}
state->state |= bits;
state->start = start;
state->end = end;
if ((end & 4095) == 0) {
printk("insert state %Lu %Lu strange end\n", start, end);
WARN_ON(1);
}
node = tree_insert(&tree->state, end, &state->rb_node);
if (node) {
struct extent_state *found;
found = rb_entry(node, struct extent_state, rb_node);
printk("found node %Lu %Lu on insert of %Lu %Lu\n", found->start, found->end, start, end);
free_extent_state(state);
return -EEXIST;
}
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.
*
* Before calling,
* the tree has 'orig' at [orig->start, orig->end]. After calling, there
* are two extent state structs in the tree:
* prealloc: [orig->start, split - 1]
* orig: [ split, orig->end ]
*
* The tree locks are not taken by this function. They need to be held
* by the caller.
*/
static int split_state(struct extent_map_tree *tree, struct extent_state *orig,
struct extent_state *prealloc, u64 split)
{
struct rb_node *node;
prealloc->start = orig->start;
prealloc->end = split - 1;
prealloc->state = orig->state;
orig->start = split;
if ((prealloc->end & 4095) == 0) {
printk("insert state %Lu %Lu strange end\n", prealloc->start,
prealloc->end);
WARN_ON(1);
}
node = tree_insert(&tree->state, prealloc->end, &prealloc->rb_node);
if (node) {
struct extent_state *found;
found = rb_entry(node, struct extent_state, rb_node);
printk("found node %Lu %Lu on insert of %Lu %Lu\n", found->start, found->end, prealloc->start, prealloc->end);
free_extent_state(prealloc);
return -EEXIST;
}
return 0;
}
/*
* utility function to clear some bits in an extent state struct.
* it will optionally wake up any one waiting on this state (wake == 1), or
* forcibly remove the state from the tree (delete == 1).
*
* If no bits are set on the state struct after clearing things, the
* struct is freed and removed from the tree
*/
static int clear_state_bit(struct extent_map_tree *tree,
struct extent_state *state, int bits, int wake,
int delete)
{
int ret = state->state & bits;
state->state &= ~bits;
if (wake)
wake_up(&state->wq);
if (delete || state->state == 0) {
if (state->in_tree) {
rb_erase(&state->rb_node, &tree->state);
state->in_tree = 0;
free_extent_state(state);
} else {
WARN_ON(1);
}
} else {
merge_state(tree, state);
}
return ret;
}
/*
* clear some bits on a range in the tree. This may require splitting
* or inserting elements in the tree, so the gfp mask is used to
* indicate which allocations or sleeping are allowed.
*
* pass 'wake' == 1 to kick any sleepers, and 'delete' == 1 to remove
* the given range from the tree regardless of state (ie for truncate).
*
* the range [start, end] is inclusive.
*
* This takes the tree lock, and returns < 0 on error, > 0 if any of the
* bits were already set, or zero if none of the bits were already set.
*/
int clear_extent_bit(struct extent_map_tree *tree, u64 start, u64 end,
int bits, int wake, int delete, gfp_t mask)
{
struct extent_state *state;
struct extent_state *prealloc = NULL;
struct rb_node *node;
int err;
int set = 0;
again:
if (!prealloc && (mask & __GFP_WAIT)) {
prealloc = alloc_extent_state(mask);
if (!prealloc)
return -ENOMEM;
}
write_lock_irq(&tree->lock);
/*
* this search will find the extents that end after
* our range starts
*/
node = tree_search(&tree->state, start);
if (!node)
goto out;
state = rb_entry(node, struct extent_state, rb_node);
if (state->start > end)
goto out;
WARN_ON(state->end < start);
/*
* | ---- 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) {
start = state->end + 1;
set |= clear_state_bit(tree, state, bits,
wake, delete);
} 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);
if (wake)
wake_up(&state->wq);
set |= clear_state_bit(tree, prealloc, bits,
wake, delete);
prealloc = NULL;
goto out;
}
start = state->end + 1;
set |= clear_state_bit(tree, state, bits, wake, delete);
goto search_again;
out:
write_unlock_irq(&tree->lock);
if (prealloc)
free_extent_state(prealloc);
return set;
search_again:
if (start >= end)
goto out;
write_unlock_irq(&tree->lock);
if (mask & __GFP_WAIT)
cond_resched();
goto again;
}
EXPORT_SYMBOL(clear_extent_bit);
static int wait_on_state(struct extent_map_tree *tree,
struct extent_state *state)
{
DEFINE_WAIT(wait);
prepare_to_wait(&state->wq, &wait, TASK_UNINTERRUPTIBLE);
read_unlock_irq(&tree->lock);
schedule();
read_lock_irq(&tree->lock);
finish_wait(&state->wq, &wait);
return 0;
}
/*
* waits for one or more bits to clear on a range in the state tree.
* The range [start, end] is inclusive.
* The tree lock is taken by this function
*/
int wait_extent_bit(struct extent_map_tree *tree, u64 start, u64 end, int bits)
{
struct extent_state *state;
struct rb_node *node;
read_lock_irq(&tree->lock);
again:
while (1) {
/*
* this search will find all the extents that end after
* our range starts
*/
node = tree_search(&tree->state, start);
if (!node)
break;
state = rb_entry(node, struct extent_state, rb_node);
if (state->start > end)
goto out;
if (state->state & bits) {
start = state->start;
atomic_inc(&state->refs);
wait_on_state(tree, state);
free_extent_state(state);
goto again;
}
start = state->end + 1;
if (start > end)
break;
if (need_resched()) {
read_unlock_irq(&tree->lock);
cond_resched();
read_lock_irq(&tree->lock);
}
}
out:
read_unlock_irq(&tree->lock);
return 0;
}
EXPORT_SYMBOL(wait_extent_bit);
/*
* set some bits on a range in the tree. This may require allocations
* or sleeping, so the gfp mask is used to indicate what is allowed.
*
* If 'exclusive' == 1, this will fail with -EEXIST if some part of the
* range already has the desired bits set. The start of the existing
* range is returned in failed_start in this case.
*
* [start, end] is inclusive
* This takes the tree lock.
*/
int set_extent_bit(struct extent_map_tree *tree, u64 start, u64 end, int bits,
int exclusive, u64 *failed_start, gfp_t mask)
{
struct extent_state *state;
struct extent_state *prealloc = NULL;
struct rb_node *node;
int err = 0;
int set;
u64 last_start;
u64 last_end;
again:
if (!prealloc && (mask & __GFP_WAIT)) {
prealloc = alloc_extent_state(mask);
if (!prealloc)
return -ENOMEM;
}
write_lock_irq(&tree->lock);
/*
* this search will find all the extents that end after
* our range starts.
*/
node = tree_search(&tree->state, start);
if (!node) {
err = insert_state(tree, prealloc, start, end, bits);
prealloc = NULL;
BUG_ON(err == -EEXIST);
goto out;
}
state = rb_entry(node, struct extent_state, rb_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) {
set = state->state & bits;
if (set && exclusive) {
*failed_start = state->start;
err = -EEXIST;
goto out;
}
state->state |= bits;
start = state->end + 1;
merge_state(tree, state);
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) {
set = state->state & bits;
if (exclusive && set) {
*failed_start = start;
err = -EEXIST;
goto out;
}
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);
} else {
start = state->start;
}
goto search_again;
}
/*
* | ---- desired range ---- |
* | state |
* We need to split the extent, and set the bit
* on the first half
*/
if (state->start <= end && state->end > end) {
set = state->state & bits;
if (exclusive && set) {
*failed_start = start;
err = -EEXIST;
goto out;
}
err = split_state(tree, state, prealloc, end + 1);
BUG_ON(err == -EEXIST);
prealloc->state |= bits;
merge_state(tree, prealloc);
prealloc = NULL;
goto out;
}
/*
* | ---- 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);
prealloc = NULL;
BUG_ON(err == -EEXIST);
if (err)
goto out;
start = this_end + 1;
goto search_again;
}
goto search_again;
out:
write_unlock_irq(&tree->lock);
if (prealloc)
free_extent_state(prealloc);
return err;
search_again:
if (start > end)
goto out;
write_unlock_irq(&tree->lock);
if (mask & __GFP_WAIT)
cond_resched();
goto again;
}
EXPORT_SYMBOL(set_extent_bit);
/* wrappers around set/clear extent bit */
int set_extent_dirty(struct extent_map_tree *tree, u64 start, u64 end,
gfp_t mask)
{
return set_extent_bit(tree, start, end, EXTENT_DIRTY, 0, NULL,
mask);
}
EXPORT_SYMBOL(set_extent_dirty);
int clear_extent_dirty(struct extent_map_tree *tree, u64 start, u64 end,
gfp_t mask)
{
return clear_extent_bit(tree, start, end, EXTENT_DIRTY, 0, 0, mask);
}
EXPORT_SYMBOL(clear_extent_dirty);
int set_extent_new(struct extent_map_tree *tree, u64 start, u64 end,
gfp_t mask)
{
return set_extent_bit(tree, start, end, EXTENT_NEW, 0, NULL,
mask);
}
EXPORT_SYMBOL(set_extent_new);
int clear_extent_new(struct extent_map_tree *tree, u64 start, u64 end,
gfp_t mask)
{
return clear_extent_bit(tree, start, end, EXTENT_NEW, 0, 0, mask);
}
EXPORT_SYMBOL(clear_extent_new);
int set_extent_uptodate(struct extent_map_tree *tree, u64 start, u64 end,
gfp_t mask)
{
return set_extent_bit(tree, start, end, EXTENT_UPTODATE, 0, NULL,
mask);
}
EXPORT_SYMBOL(set_extent_uptodate);
int clear_extent_uptodate(struct extent_map_tree *tree, u64 start, u64 end,
gfp_t mask)
{
return clear_extent_bit(tree, start, end, EXTENT_UPTODATE, 0, 0, mask);
}
EXPORT_SYMBOL(clear_extent_uptodate);
int set_extent_writeback(struct extent_map_tree *tree, u64 start, u64 end,
gfp_t mask)
{
return set_extent_bit(tree, start, end, EXTENT_WRITEBACK,
0, NULL, mask);
}
EXPORT_SYMBOL(set_extent_writeback);
int clear_extent_writeback(struct extent_map_tree *tree, u64 start, u64 end,
gfp_t mask)
{
return clear_extent_bit(tree, start, end, EXTENT_WRITEBACK, 1, 0, mask);
}
EXPORT_SYMBOL(clear_extent_writeback);
int wait_on_extent_writeback(struct extent_map_tree *tree, u64 start, u64 end)
{
return wait_extent_bit(tree, start, end, EXTENT_WRITEBACK);
}
EXPORT_SYMBOL(wait_on_extent_writeback);
/*
* locks a range in ascending order, waiting for any locked regions
* it hits on the way. [start,end] are inclusive, and this will sleep.
*/
int lock_extent(struct extent_map_tree *tree, u64 start, u64 end, gfp_t mask)
{
int err;
u64 failed_start;
while (1) {
err = set_extent_bit(tree, start, end, EXTENT_LOCKED, 1,
&failed_start, mask);
if (err == -EEXIST && (mask & __GFP_WAIT)) {
wait_extent_bit(tree, failed_start, end, EXTENT_LOCKED);
start = failed_start;
} else {
break;
}
WARN_ON(start > end);
}
return err;
}
EXPORT_SYMBOL(lock_extent);
int unlock_extent(struct extent_map_tree *tree, u64 start, u64 end,
gfp_t mask)
{
return clear_extent_bit(tree, start, end, EXTENT_LOCKED, 1, 0, mask);
}
EXPORT_SYMBOL(unlock_extent);
/*
* helper function to set pages and extents in the tree dirty
*/
int set_range_dirty(struct extent_map_tree *tree, u64 start, u64 end)
{
unsigned long index = start >> PAGE_CACHE_SHIFT;
unsigned long end_index = end >> PAGE_CACHE_SHIFT;
struct page *page;
while (index <= end_index) {
page = find_get_page(tree->mapping, index);
BUG_ON(!page);
__set_page_dirty_nobuffers(page);
page_cache_release(page);
index++;
}
set_extent_dirty(tree, start, end, GFP_NOFS);
return 0;
}
EXPORT_SYMBOL(set_range_dirty);
/*
* helper function to set both pages and extents in the tree writeback
*/
int set_range_writeback(struct extent_map_tree *tree, u64 start, u64 end)
{
unsigned long index = start >> PAGE_CACHE_SHIFT;
unsigned long end_index = end >> PAGE_CACHE_SHIFT;
struct page *page;
while (index <= end_index) {
page = find_get_page(tree->mapping, index);
BUG_ON(!page);
set_page_writeback(page);
page_cache_release(page);
index++;
}
set_extent_writeback(tree, start, end, GFP_NOFS);
return 0;
}
EXPORT_SYMBOL(set_range_writeback);
/*
* helper function to lock both pages and extents in the tree.
* pages must be locked first.
*/
int lock_range(struct extent_map_tree *tree, u64 start, u64 end)
{
unsigned long index = start >> PAGE_CACHE_SHIFT;
unsigned long end_index = end >> PAGE_CACHE_SHIFT;
struct page *page;
int err;
while (index <= end_index) {
page = grab_cache_page(tree->mapping, index);
if (!page) {
err = -ENOMEM;
goto failed;
}
if (IS_ERR(page)) {
err = PTR_ERR(page);
goto failed;
}
index++;
}
lock_extent(tree, start, end, GFP_NOFS);
return 0;
failed:
/*
* we failed above in getting the page at 'index', so we undo here
* up to but not including the page at 'index'
*/
end_index = index;
index = start >> PAGE_CACHE_SHIFT;
while (index < end_index) {
page = find_get_page(tree->mapping, index);
unlock_page(page);
page_cache_release(page);
index++;
}
return err;
}
EXPORT_SYMBOL(lock_range);
/*
* helper function to unlock both pages and extents in the tree.
*/
int unlock_range(struct extent_map_tree *tree, u64 start, u64 end)
{
unsigned long index = start >> PAGE_CACHE_SHIFT;
unsigned long end_index = end >> PAGE_CACHE_SHIFT;
struct page *page;
while (index <= end_index) {
page = find_get_page(tree->mapping, index);
unlock_page(page);
page_cache_release(page);
index++;
}
unlock_extent(tree, start, end, GFP_NOFS);
return 0;
}
EXPORT_SYMBOL(unlock_range);
/*
* searches a range in the state tree for a given mask.
* If 'filled' == 1, this returns 1 only if ever extent in the tree
* has the bits set. Otherwise, 1 is returned if any bit in the
* range is found set.
*/
static int test_range_bit(struct extent_map_tree *tree, u64 start, u64 end,
int bits, int filled)
{
struct extent_state *state = NULL;
struct rb_node *node;
int bitset = 0;
read_lock_irq(&tree->lock);
node = tree_search(&tree->state, start);
while (node && start <= end) {
state = rb_entry(node, struct extent_state, rb_node);
if (state->start > end)
break;
if (filled && state->start > start) {
bitset = 0;
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 = rb_next(node);
}
read_unlock_irq(&tree->lock);
return bitset;
}
/*
* helper function to set a given page up to date if all the
* extents in the tree for that page are up to date
*/
static int check_page_uptodate(struct extent_map_tree *tree,
struct page *page)
{
u64 start = page->index << PAGE_CACHE_SHIFT;
u64 end = start + PAGE_CACHE_SIZE - 1;
if (test_range_bit(tree, start, end, EXTENT_UPTODATE, 1))
SetPageUptodate(page);
return 0;
}
/*
* helper function to unlock a page if all the extents in the tree
* for that page are unlocked
*/
static int check_page_locked(struct extent_map_tree *tree,
struct page *page)
{
u64 start = page->index << PAGE_CACHE_SHIFT;
u64 end = start + PAGE_CACHE_SIZE - 1;
if (!test_range_bit(tree, start, end, EXTENT_LOCKED, 0))
unlock_page(page);
return 0;
}
/*
* helper function to end page writeback if all the extents
* in the tree for that page are done with writeback
*/
static int check_page_writeback(struct extent_map_tree *tree,
struct page *page)
{
u64 start = page->index << PAGE_CACHE_SHIFT;
u64 end = start + PAGE_CACHE_SIZE - 1;
if (!test_range_bit(tree, start, end, EXTENT_WRITEBACK, 0))
end_page_writeback(page);
return 0;
}
/* lots and lots of room for performance fixes in the end_bio funcs */
/*
* after a writepage IO is done, we need to:
* clear the uptodate bits on error
* clear the writeback bits in the extent tree for this IO
* end_page_writeback if the page has no more pending IO
*
* Scheduling is not allowed, so the extent state tree is expected
* to have one and only one object corresponding to this IO.
*/
static int end_bio_extent_writepage(struct bio *bio,
unsigned int bytes_done, int err)
{
const int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
struct bio_vec *bvec = bio->bi_io_vec + bio->bi_vcnt - 1;
struct extent_map_tree *tree = bio->bi_private;
u64 start;
u64 end;
int whole_page;
if (bio->bi_size)
return 1;
do {
struct page *page = bvec->bv_page;
start = (page->index << PAGE_CACHE_SHIFT) + bvec->bv_offset;
end = start + bvec->bv_len - 1;
if (bvec->bv_offset == 0 && bvec->bv_len == PAGE_CACHE_SIZE)
whole_page = 1;
else
whole_page = 0;
if (--bvec >= bio->bi_io_vec)
prefetchw(&bvec->bv_page->flags);
if (!uptodate) {
clear_extent_uptodate(tree, start, end, GFP_ATOMIC);
ClearPageUptodate(page);
SetPageError(page);
}
clear_extent_writeback(tree, start, end, GFP_ATOMIC);
if (whole_page)
end_page_writeback(page);
else
check_page_writeback(tree, page);
} while (bvec >= bio->bi_io_vec);
bio_put(bio);
return 0;
}
/*
* after a readpage IO is done, we need to:
* clear the uptodate bits on error
* set the uptodate bits if things worked
* set the page up to date if all extents in the tree are uptodate
* clear the lock bit in the extent tree
* unlock the page if there are no other extents locked for it
*
* Scheduling is not allowed, so the extent state tree is expected
* to have one and only one object corresponding to this IO.
*/
static int end_bio_extent_readpage(struct bio *bio,
unsigned int bytes_done, int err)
{
const int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
struct bio_vec *bvec = bio->bi_io_vec + bio->bi_vcnt - 1;
struct extent_map_tree *tree = bio->bi_private;
u64 start;
u64 end;
int whole_page;
if (bio->bi_size)
return 1;
do {
struct page *page = bvec->bv_page;
start = (page->index << PAGE_CACHE_SHIFT) + bvec->bv_offset;
end = start + bvec->bv_len - 1;
if (bvec->bv_offset == 0 && bvec->bv_len == PAGE_CACHE_SIZE)
whole_page = 1;
else
whole_page = 0;
if (--bvec >= bio->bi_io_vec)
prefetchw(&bvec->bv_page->flags);
if (uptodate) {
set_extent_uptodate(tree, start, end, GFP_ATOMIC);
if (whole_page)
SetPageUptodate(page);
else
check_page_uptodate(tree, page);
} else {
ClearPageUptodate(page);
SetPageError(page);
}
unlock_extent(tree, start, end, GFP_ATOMIC);
if (whole_page)
unlock_page(page);
else
check_page_locked(tree, page);
} while (bvec >= bio->bi_io_vec);
bio_put(bio);
return 0;
}
/*
* IO done from prepare_write is pretty simple, we just unlock
* the structs in the extent tree when done, and set the uptodate bits
* as appropriate.
*/
static int end_bio_extent_preparewrite(struct bio *bio,
unsigned int bytes_done, int err)
{
const int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
struct bio_vec *bvec = bio->bi_io_vec + bio->bi_vcnt - 1;
struct extent_map_tree *tree = bio->bi_private;
u64 start;
u64 end;
if (bio->bi_size)
return 1;
do {
struct page *page = bvec->bv_page;
start = (page->index << PAGE_CACHE_SHIFT) + bvec->bv_offset;
end = start + bvec->bv_len - 1;
if (--bvec >= bio->bi_io_vec)
prefetchw(&bvec->bv_page->flags);
if (uptodate) {
set_extent_uptodate(tree, start, end, GFP_ATOMIC);
} else {
ClearPageUptodate(page);
SetPageError(page);
}
unlock_extent(tree, start, end, GFP_ATOMIC);
} while (bvec >= bio->bi_io_vec);
bio_put(bio);
return 0;
}
static int submit_extent_page(int rw, struct extent_map_tree *tree,
struct page *page, sector_t sector,
size_t size, unsigned long offset,
struct block_device *bdev,
bio_end_io_t end_io_func)
{
struct bio *bio;
int ret = 0;
bio = bio_alloc(GFP_NOIO, 1);
bio->bi_sector = sector;
bio->bi_bdev = bdev;
bio->bi_io_vec[0].bv_page = page;
bio->bi_io_vec[0].bv_len = size;
bio->bi_io_vec[0].bv_offset = offset;
bio->bi_vcnt = 1;
bio->bi_idx = 0;
bio->bi_size = size;
bio->bi_end_io = end_io_func;
bio->bi_private = tree;
bio_get(bio);
submit_bio(rw, bio);
if (bio_flagged(bio, BIO_EOPNOTSUPP))
ret = -EOPNOTSUPP;
bio_put(bio);
return ret;
}
/*
* basic readpage implementation. Locked extent state structs are inserted
* into the tree that are removed when the IO is done (by the end_io
* handlers)
*/
int extent_read_full_page(struct extent_map_tree *tree, struct page *page,
get_extent_t *get_extent)
{
struct inode *inode = page->mapping->host;
u64 start = page->index << PAGE_CACHE_SHIFT;
u64 page_end = start + PAGE_CACHE_SIZE - 1;
u64 end;
u64 cur = start;
u64 extent_offset;
u64 last_byte = i_size_read(inode);
u64 block_start;
u64 cur_end;
sector_t sector;
struct extent_map *em;
struct block_device *bdev;
int ret;
int nr = 0;
size_t page_offset = 0;
size_t iosize;
size_t blocksize = inode->i_sb->s_blocksize;
if (!PagePrivate(page)) {
SetPagePrivate(page);
set_page_private(page, 1);
page_cache_get(page);
}
end = page_end;
lock_extent(tree, start, end, GFP_NOFS);
while (cur <= end) {
if (cur >= last_byte) {
iosize = PAGE_CACHE_SIZE - page_offset;
zero_user_page(page, page_offset, iosize, KM_USER0);
set_extent_uptodate(tree, cur, cur + iosize - 1,
GFP_NOFS);
unlock_extent(tree, cur, cur + iosize - 1, GFP_NOFS);
break;
}
em = get_extent(inode, page, page_offset, cur, end, 0);
if (IS_ERR(em) || !em) {
SetPageError(page);
unlock_extent(tree, cur, end, GFP_NOFS);
break;
}
extent_offset = cur - em->start;
BUG_ON(em->end < cur);
BUG_ON(end < cur);
iosize = min(em->end - cur, end - cur) + 1;
cur_end = min(em->end, end);
iosize = (iosize + blocksize - 1) & ~((u64)blocksize - 1);
sector = (em->block_start + extent_offset) >> 9;
bdev = em->bdev;
block_start = em->block_start;
free_extent_map(em);
em = NULL;
/* we've found a hole, just zero and go on */
if (block_start == 0) {
zero_user_page(page, page_offset, iosize, KM_USER0);
set_extent_uptodate(tree, cur, cur + iosize - 1,
GFP_NOFS);
unlock_extent(tree, cur, cur + iosize - 1, GFP_NOFS);
cur = cur + iosize;
page_offset += iosize;
continue;
}
/* the get_extent function already copied into the page */
if (test_range_bit(tree, cur, cur_end, EXTENT_UPTODATE, 1)) {
unlock_extent(tree, cur, cur + iosize - 1, GFP_NOFS);
cur = cur + iosize;
page_offset += iosize;
continue;
}
ret = submit_extent_page(READ, tree, page,
sector, iosize, page_offset, bdev,
end_bio_extent_readpage);
if (ret)
SetPageError(page);
cur = cur + iosize;
page_offset += iosize;
nr++;
}
if (!nr) {
if (!PageError(page))
SetPageUptodate(page);
unlock_page(page);
}
return 0;
}
EXPORT_SYMBOL(extent_read_full_page);
/*
* the writepage semantics are similar to regular writepage. extent
* records are inserted to lock ranges in the tree, and as dirty areas
* are found, they are marked writeback. Then the lock bits are removed
* and the end_io handler clears the writeback ranges
*/
int extent_write_full_page(struct extent_map_tree *tree, struct page *page,
get_extent_t *get_extent,
struct writeback_control *wbc)
{
struct inode *inode = page->mapping->host;
u64 start = page->index << PAGE_CACHE_SHIFT;
u64 page_end = start + PAGE_CACHE_SIZE - 1;
u64 end;
u64 cur = start;
u64 extent_offset;
u64 last_byte = i_size_read(inode);
u64 block_start;
sector_t sector;
struct extent_map *em;
struct block_device *bdev;
int ret;
int nr = 0;
size_t page_offset = 0;
size_t iosize;
size_t blocksize;
loff_t i_size = i_size_read(inode);
unsigned long end_index = i_size >> PAGE_CACHE_SHIFT;
if (page->index > end_index) {
clear_extent_dirty(tree, start, page_end, GFP_NOFS);
unlock_page(page);
return 0;
}
if (page->index == end_index) {
size_t offset = i_size & (PAGE_CACHE_SIZE - 1);
zero_user_page(page, offset,
PAGE_CACHE_SIZE - offset, KM_USER0);
}
if (!PagePrivate(page)) {
SetPagePrivate(page);
set_page_private(page, 1);
page_cache_get(page);
}
end = page_end;
lock_extent(tree, start, page_end, GFP_NOFS);
if (last_byte <= start) {
clear_extent_dirty(tree, start, page_end, GFP_NOFS);
goto done;
}
set_extent_uptodate(tree, start, page_end, GFP_NOFS);
blocksize = inode->i_sb->s_blocksize;
while (cur <= end) {
if (cur >= last_byte) {
clear_extent_dirty(tree, cur, page_end, GFP_NOFS);
break;
}
em = get_extent(inode, page, page_offset, cur, end, 1);
if (IS_ERR(em) || !em) {
SetPageError(page);
break;
}
extent_offset = cur - em->start;
BUG_ON(em->end < cur);
BUG_ON(end < cur);
iosize = min(em->end - cur, end - cur) + 1;
iosize = (iosize + blocksize - 1) & ~((u64)blocksize - 1);
sector = (em->block_start + extent_offset) >> 9;
bdev = em->bdev;
block_start = em->block_start;
free_extent_map(em);
em = NULL;
if (block_start == 0 || block_start == EXTENT_MAP_INLINE) {
clear_extent_dirty(tree, cur,
cur + iosize - 1, GFP_NOFS);
cur = cur + iosize;
page_offset += iosize;
continue;
}
/* leave this out until we have a page_mkwrite call */
if (0 && !test_range_bit(tree, cur, cur + iosize - 1,
EXTENT_DIRTY, 0)) {
cur = cur + iosize;
page_offset += iosize;
continue;
}
clear_extent_dirty(tree, cur, cur + iosize - 1, GFP_NOFS);
set_range_writeback(tree, cur, cur + iosize - 1);
ret = submit_extent_page(WRITE, tree, page,
sector, iosize, page_offset, bdev,
end_bio_extent_writepage);
if (ret)
SetPageError(page);
cur = cur + iosize;
page_offset += iosize;
nr++;
}
done:
WARN_ON(test_range_bit(tree, start, page_end, EXTENT_DIRTY, 0));
unlock_extent(tree, start, page_end, GFP_NOFS);
unlock_page(page);
return 0;
}
EXPORT_SYMBOL(extent_write_full_page);
/*
* basic invalidatepage code, this waits on any locked or writeback
* ranges corresponding to the page, and then deletes any extent state
* records from the tree
*/
int extent_invalidatepage(struct extent_map_tree *tree,
struct page *page, unsigned long offset)
{
u64 start = (page->index << PAGE_CACHE_SHIFT);
u64 end = start + PAGE_CACHE_SIZE - 1;
size_t blocksize = page->mapping->host->i_sb->s_blocksize;
start += (offset + blocksize -1) & ~(blocksize - 1);
if (start > end)
return 0;
lock_extent(tree, start, end, GFP_NOFS);
wait_on_extent_writeback(tree, start, end);
clear_extent_bit(tree, start, end, EXTENT_LOCKED | EXTENT_DIRTY,
1, 1, GFP_NOFS);
return 0;
}
EXPORT_SYMBOL(extent_invalidatepage);
/*
* simple commit_write call, set_range_dirty is used to mark both
* the pages and the extent records as dirty
*/
int extent_commit_write(struct extent_map_tree *tree,
struct inode *inode, struct page *page,
unsigned from, unsigned to)
{
loff_t pos = ((loff_t)page->index << PAGE_CACHE_SHIFT) + to;
if (!PagePrivate(page)) {
SetPagePrivate(page);
set_page_private(page, 1);
page_cache_get(page);
}
set_page_dirty(page);
if (pos > inode->i_size) {
i_size_write(inode, pos);
mark_inode_dirty(inode);
}
return 0;
}
EXPORT_SYMBOL(extent_commit_write);
int extent_prepare_write(struct extent_map_tree *tree,
struct inode *inode, struct page *page,
unsigned from, unsigned to, get_extent_t *get_extent)
{
u64 page_start = page->index << PAGE_CACHE_SHIFT;
u64 page_end = page_start + PAGE_CACHE_SIZE - 1;
u64 block_start;
u64 orig_block_start;
u64 block_end;
u64 cur_end;
struct extent_map *em;
unsigned blocksize = 1 << inode->i_blkbits;
size_t page_offset = 0;
size_t block_off_start;
size_t block_off_end;
int err = 0;
int iocount = 0;
int ret = 0;
int isnew;
if (!PagePrivate(page)) {
SetPagePrivate(page);
set_page_private(page, 1);
page_cache_get(page);
}
block_start = (page_start + from) & ~((u64)blocksize - 1);
block_end = (page_start + to - 1) | (blocksize - 1);
orig_block_start = block_start;
lock_extent(tree, page_start, page_end, GFP_NOFS);
while(block_start <= block_end) {
em = get_extent(inode, page, page_offset, block_start,
block_end, 1);
if (IS_ERR(em) || !em) {
goto err;
}
cur_end = min(block_end, em->end);
block_off_start = block_start & (PAGE_CACHE_SIZE - 1);
block_off_end = block_off_start + blocksize;
isnew = clear_extent_new(tree, block_start, cur_end, GFP_NOFS);
if (!PageUptodate(page) && isnew &&
(block_off_end > to || block_off_start < from)) {
void *kaddr;
kaddr = kmap_atomic(page, KM_USER0);
if (block_off_end > to)
memset(kaddr + to, 0, block_off_end - to);
if (block_off_start < from)
memset(kaddr + block_off_start, 0,
from - block_off_start);
flush_dcache_page(page);
kunmap_atomic(kaddr, KM_USER0);
}
if (!isnew && !PageUptodate(page) &&
(block_off_end > to || block_off_start < from) &&
!test_range_bit(tree, block_start, cur_end,
EXTENT_UPTODATE, 1)) {
u64 sector;
u64 extent_offset = block_start - em->start;
size_t iosize;
sector = (em->block_start + extent_offset) >> 9;
iosize = (cur_end - block_start + blocksize - 1) &
~((u64)blocksize - 1);
/*
* we've already got the extent locked, but we
* need to split the state such that our end_bio
* handler can clear the lock.
*/
set_extent_bit(tree, block_start,
block_start + iosize - 1,
EXTENT_LOCKED, 0, NULL, GFP_NOFS);
ret = submit_extent_page(READ, tree, page,
sector, iosize, page_offset, em->bdev,
end_bio_extent_preparewrite);
iocount++;
block_start = block_start + iosize;
} else {
set_extent_uptodate(tree, block_start, cur_end,
GFP_NOFS);
unlock_extent(tree, block_start, cur_end, GFP_NOFS);
block_start = cur_end + 1;
}
page_offset = block_start & (PAGE_CACHE_SIZE - 1);
free_extent_map(em);
}
if (iocount) {
wait_extent_bit(tree, orig_block_start,
block_end, EXTENT_LOCKED);
}
check_page_uptodate(tree, page);
err:
/* FIXME, zero out newly allocated blocks on error */
return err;
}
EXPORT_SYMBOL(extent_prepare_write);
/*
* a helper for releasepage. As long as there are no locked extents
* in the range corresponding to the page, both state records and extent
* map records are removed
*/
int try_release_extent_mapping(struct extent_map_tree *tree, struct page *page)
{
struct extent_map *em;
u64 start = page->index << PAGE_CACHE_SHIFT;
u64 end = start + PAGE_CACHE_SIZE - 1;
u64 orig_start = start;
while (start <= end) {
em = lookup_extent_mapping(tree, start, end);
if (!em || IS_ERR(em))
break;
if (test_range_bit(tree, em->start, em->end,
EXTENT_LOCKED, 0)) {
free_extent_map(em);
start = em->end + 1;
printk("range still locked %Lu %Lu\n", em->start, em->end);
break;
}
remove_extent_mapping(tree, em);
start = em->end + 1;
/* once for the rb tree */
free_extent_map(em);
/* once for us */
free_extent_map(em);
}
WARN_ON(test_range_bit(tree, orig_start, end, EXTENT_WRITEBACK, 0));
clear_extent_bit(tree, orig_start, end, EXTENT_UPTODATE,
1, 1, GFP_NOFS);
return 1;
}
EXPORT_SYMBOL(try_release_extent_mapping);
fs/btrfs/extent_map.h 0 → 100644
View file @ a52d9a80
#ifndef __EXTENTMAP__
#define __EXTENTMAP__
#include <linux/rbtree.h>
#define EXTENT_MAP_INLINE (u64)-2
#define EXTENT_MAP_DELALLOC (u64)-1
struct extent_map_tree {
struct rb_root map;
struct rb_root state;
struct address_space *mapping;
rwlock_t lock;
};
/* note, this must start with the same fields as fs/extent_map.c:tree_entry */
struct extent_map {
u64 start;
u64 end; /* inclusive */
int in_tree;
struct rb_node rb_node;
/* block_start and block_end are in bytes */
u64 block_start;
u64 block_end; /* inclusive */
struct block_device *bdev;
atomic_t refs;
};
/* note, this must start with the same fields as fs/extent_map.c:tree_entry */
struct extent_state {
u64 start;
u64 end; /* inclusive */
int in_tree;
struct rb_node rb_node;
wait_queue_head_t wq;
atomic_t refs;
unsigned long state;
struct list_head list;
};
struct extent_buffer {
u64 start;
u64 end; /* inclusive */
char *addr;
struct page *pages[];
};
typedef struct extent_map *(get_extent_t)(struct inode *inode,
struct page *page,
size_t page_offset,
u64 start, u64 end,
int create);
void extent_map_tree_init(struct extent_map_tree *tree,
struct address_space *mapping, gfp_t mask);
struct extent_map *lookup_extent_mapping(struct extent_map_tree *tree,
u64 start, u64 end);
int add_extent_mapping(struct extent_map_tree *tree,
struct extent_map *em);
int remove_extent_mapping(struct extent_map_tree *tree, struct extent_map *em);
int try_release_extent_mapping(struct extent_map_tree *tree, struct page *page);
int lock_extent(struct extent_map_tree *tree, u64 start, u64 end, gfp_t mask);
int unlock_extent(struct extent_map_tree *tree, u64 start, u64 end, gfp_t mask);
struct extent_map *alloc_extent_map(gfp_t mask);
void free_extent_map(struct extent_map *em);
int extent_read_full_page(struct extent_map_tree *tree, struct page *page,
get_extent_t *get_extent);
void __init extent_map_init(void);
void __exit extent_map_exit(void);
int extent_clean_all_trees(struct extent_map_tree *tree);
int set_extent_uptodate(struct extent_map_tree *tree, u64 start, u64 end,
gfp_t mask);
int set_extent_new(struct extent_map_tree *tree, u64 start, u64 end,
gfp_t mask);
int set_extent_dirty(struct extent_map_tree *tree, u64 start, u64 end,
gfp_t mask);
int extent_invalidatepage(struct extent_map_tree *tree,
struct page *page, unsigned long offset);
int extent_write_full_page(struct extent_map_tree *tree, struct page *page,
get_extent_t *get_extent,
struct writeback_control *wbc);
int extent_prepare_write(struct extent_map_tree *tree,
struct inode *inode, struct page *page,
unsigned from, unsigned to, get_extent_t *get_extent);
int extent_commit_write(struct extent_map_tree *tree,
struct inode *inode, struct page *page,
unsigned from, unsigned to);
int set_range_dirty(struct extent_map_tree *tree, u64 start, u64 end);
#endif
fs/btrfs/file.c
View file @ a52d9a80
......@@ -81,14 +81,14 @@ static void btrfs_drop_pages(struct page **pages, size_t num_pages)
}
}
static int insert_inline_extent(struct btrfs_root *root, struct inode *inode,
static int insert_inline_extent(struct btrfs_trans_handle *trans,
struct btrfs_root *root, struct inode *inode,
u64 offset, ssize_t size,
struct buffer_head *bh)
struct page *page, size_t page_offset)
{
struct btrfs_key key;
struct btrfs_path *path;
char *ptr, *kaddr;
struct btrfs_trans_handle *trans;
struct btrfs_file_extent_item *ei;
u32 datasize;
int err = 0;
......@@ -98,8 +98,6 @@ static int insert_inline_extent(struct btrfs_root *root, struct inode *inode,
if (!path)
return -ENOMEM;
mutex_lock(&root->fs_info->fs_mutex);
trans = btrfs_start_transaction(root, 1);
btrfs_set_trans_block_group(trans, inode);
key.objectid = inode->i_ino;
......@@ -122,18 +120,13 @@ static int insert_inline_extent(struct btrfs_root *root, struct inode *inode,
BTRFS_FILE_EXTENT_INLINE);
ptr = btrfs_file_extent_inline_start(ei);
kaddr = kmap_atomic(bh->b_page, KM_USER0);
kaddr = kmap_atomic(page, KM_USER0);
btrfs_memcpy(root, path->nodes[0]->b_data,
ptr, kaddr + bh_offset(bh),
size);
ptr, kaddr + page_offset, size);
kunmap_atomic(kaddr, KM_USER0);
btrfs_mark_buffer_dirty(path->nodes[0]);
fail:
btrfs_free_path(path);
ret = btrfs_end_transaction(trans, root);
if (ret && !err)
err = ret;
mutex_unlock(&root->fs_info->fs_mutex);
return err;
}
......@@ -145,45 +138,143 @@ static int dirty_and_release_pages(struct btrfs_trans_handle *trans,
loff_t pos,
size_t write_bytes)
{
int i;
int offset;
int err = 0;
int ret;
int this_write;
int i;
struct inode *inode = file->f_path.dentry->d_inode;
struct buffer_head *bh;
struct extent_map *em;
struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
struct btrfs_key ins;
u64 hint_block;
u64 num_blocks;
u64 start_pos;
u64 end_of_last_block;
u64 end_pos = pos + write_bytes;
loff_t isize = i_size_read(inode);
for (i = 0; i < num_pages; i++) {
offset = pos & (PAGE_CACHE_SIZE -1);
this_write = min((size_t)PAGE_CACHE_SIZE - offset, write_bytes);
em = alloc_extent_map(GFP_NOFS);
if (!em)
return -ENOMEM;
/* FIXME, one block at a time */
bh = page_buffers(pages[i]);
em->bdev = inode->i_sb->s_bdev;
if (buffer_mapped(bh) && bh->b_blocknr == 0) {
ret = insert_inline_extent(root, inode,
pages[i]->index << PAGE_CACHE_SHIFT,
offset + this_write, bh);
if (ret) {
err = ret;
goto failed;
}
}
start_pos = pos & ~((u64)root->blocksize - 1);
num_blocks = (write_bytes + pos - start_pos + root->blocksize - 1) >>
inode->i_blkbits;
ret = btrfs_commit_write(file, pages[i], offset,
offset + this_write);
pos += this_write;
if (ret) {
err = ret;
end_of_last_block = start_pos + (num_blocks << inode->i_blkbits) - 1;
mutex_lock(&root->fs_info->fs_mutex);
trans = btrfs_start_transaction(root, 1);
if (!trans) {
err = -ENOMEM;
goto out_unlock;
}
btrfs_set_trans_block_group(trans, inode);
inode->i_blocks += num_blocks << 3;
hint_block = 0;
if ((end_of_last_block & 4095) == 0) {
printk("strange end of last %Lu %lu %Lu\n", start_pos, write_bytes, end_of_last_block);
}
set_extent_uptodate(em_tree, start_pos, end_of_last_block, GFP_NOFS);
/* FIXME...EIEIO, ENOSPC and more */
/* step one, delete the existing extents in this range */
/* FIXME blocksize != pagesize */
if (start_pos < inode->i_size) {
err = btrfs_drop_extents(trans, root, inode,
start_pos, (pos + write_bytes + root->blocksize -1) &
~((u64)root->blocksize - 1), &hint_block);
if (err)
goto failed;
}
/* insert any holes we need to create */
if (inode->i_size < start_pos) {
u64 last_pos_in_file;
u64 hole_size;
u64 mask = root->blocksize - 1;
last_pos_in_file = (isize + mask) & ~mask;
hole_size = (start_pos - last_pos_in_file + mask) & ~mask;
hole_size >>= inode->i_blkbits;
if (last_pos_in_file < start_pos) {
err = btrfs_insert_file_extent(trans, root,
inode->i_ino,
last_pos_in_file,
0, 0, hole_size);
}
if (err)
goto failed;
}
/*
* either allocate an extent for the new bytes or setup the key
* to show we are doing inline data in the extent
*/
if (isize >= PAGE_CACHE_SIZE || pos + write_bytes < inode->i_size ||
pos + write_bytes - start_pos > BTRFS_MAX_INLINE_DATA_SIZE(root)) {
err = btrfs_alloc_extent(trans, root, inode->i_ino,
num_blocks, 0, hint_block, (u64)-1,
&ins, 1);
BUG_ON(err);
err = btrfs_insert_file_extent(trans, root, inode->i_ino,
start_pos, ins.objectid, ins.offset,
ins.offset);
BUG_ON(err);
em->start = start_pos;
em->end = end_of_last_block;
em->block_start = ins.objectid << inode->i_blkbits;
em->block_end = em->block_start +
(ins.offset << inode->i_blkbits) - 1;
set_extent_dirty(em_tree, start_pos, end_of_last_block,
GFP_NOFS);
err = add_extent_mapping(em_tree, em);
for (i = 0; i < num_pages; i++) {
struct page *p = pages[i];
SetPageUptodate(p);
__set_page_dirty_nobuffers(p);
}
WARN_ON(this_write > write_bytes);
write_bytes -= this_write;
} else {
struct page *p = pages[0];
err = insert_inline_extent(trans, root, inode, start_pos,
end_pos - start_pos, p, 0);
BUG_ON(err);
em->start = start_pos;
em->end = end_pos;
em->block_start = EXTENT_MAP_INLINE;
em->block_end = EXTENT_MAP_INLINE;
add_extent_mapping(em_tree, em);
}
if (end_pos > isize) {
i_size_write(inode, end_pos);
btrfs_update_inode(trans, root, inode);
}
failed:
err = btrfs_end_transaction(trans, root);
out_unlock:
mutex_unlock(&root->fs_info->fs_mutex);
free_extent_map(em);
return err;
}
int btrfs_drop_extent_cache(struct inode *inode, u64 start, u64 end)
{
struct extent_map *em;
struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
while(1) {
em = lookup_extent_mapping(em_tree, start, end);
if (!em)
break;
remove_extent_mapping(em_tree, em);
/* once for us */
free_extent_map(em);
/* once for the tree*/
free_extent_map(em);
}
return 0;
}
/*
* this is very complex, but the basic idea is to drop all extents
* in the range start - end. hint_block is filled in with a block number
......@@ -213,6 +304,8 @@ int btrfs_drop_extents(struct btrfs_trans_handle *trans,
int found_inline;
int recow;
btrfs_drop_extent_cache(inode, start, end - 1);
path = btrfs_alloc_path();
if (!path)
return -ENOMEM;
......@@ -434,18 +527,9 @@ static int prepare_pages(struct btrfs_root *root,
int i;
unsigned long index = pos >> PAGE_CACHE_SHIFT;
struct inode *inode = file->f_path.dentry->d_inode;
int offset;
int err = 0;
int this_write;
struct buffer_head *bh;
struct buffer_head *head;
loff_t isize = i_size_read(inode);
struct btrfs_trans_handle *trans;
u64 hint_block;
u64 num_blocks;
u64 alloc_extent_start;
u64 start_pos;
struct btrfs_key ins;
start_pos = pos & ~((u64)PAGE_CACHE_SIZE - 1);
num_blocks = (write_bytes + pos - start_pos + root->blocksize - 1) >>
......@@ -457,119 +541,17 @@ static int prepare_pages(struct btrfs_root *root,
pages[i] = grab_cache_page(inode->i_mapping, index + i);
if (!pages[i]) {
err = -ENOMEM;
goto failed_release;
BUG_ON(1);
}
cancel_dirty_page(pages[i], PAGE_CACHE_SIZE);
wait_on_page_writeback(pages[i]);
}
mutex_lock(&root->fs_info->fs_mutex);
trans = btrfs_start_transaction(root, 1);
if (!trans) {
err = -ENOMEM;
mutex_unlock(&root->fs_info->fs_mutex);
goto out_unlock;
}
btrfs_set_trans_block_group(trans, inode);
/* FIXME blocksize != 4096 */
inode->i_blocks += num_blocks << 3;
hint_block = 0;
/* FIXME...EIEIO, ENOSPC and more */
/* step one, delete the existing extents in this range */
/* FIXME blocksize != pagesize */
if (start_pos < inode->i_size) {
err = btrfs_drop_extents(trans, root, inode,
start_pos, (pos + write_bytes + root->blocksize -1) &
~((u64)root->blocksize - 1), &hint_block);
if (err)
goto failed_release;
}
/* insert any holes we need to create */
if (inode->i_size < start_pos) {
u64 last_pos_in_file;
u64 hole_size;
u64 mask = root->blocksize - 1;
last_pos_in_file = (isize + mask) & ~mask;
hole_size = (start_pos - last_pos_in_file + mask) & ~mask;
hole_size >>= inode->i_blkbits;
if (last_pos_in_file < start_pos) {
err = btrfs_insert_file_extent(trans, root,
inode->i_ino,
last_pos_in_file,
0, 0, hole_size);
}
if (err)
goto failed_release;
}
/*
* either allocate an extent for the new bytes or setup the key
* to show we are doing inline data in the extent
*/
if (isize >= PAGE_CACHE_SIZE || pos + write_bytes < inode->i_size ||
pos + write_bytes - start_pos > BTRFS_MAX_INLINE_DATA_SIZE(root)) {
err = btrfs_alloc_extent(trans, root, inode->i_ino,
num_blocks, 0, hint_block, (u64)-1,
&ins, 1);
if (err)
goto failed_truncate;
err = btrfs_insert_file_extent(trans, root, inode->i_ino,
start_pos, ins.objectid, ins.offset,
ins.offset);
if (err)
goto failed_truncate;
} else {
ins.offset = 0;
ins.objectid = 0;
}
BUG_ON(err);
alloc_extent_start = ins.objectid;
err = btrfs_end_transaction(trans, root);
mutex_unlock(&root->fs_info->fs_mutex);
for (i = 0; i < num_pages; i++) {
offset = pos & (PAGE_CACHE_SIZE -1);
this_write = min((size_t)PAGE_CACHE_SIZE - offset, write_bytes);
if (!page_has_buffers(pages[i])) {
create_empty_buffers(pages[i],
root->fs_info->sb->s_blocksize,
(1 << BH_Uptodate));
if (!PagePrivate(pages[i])) {
SetPagePrivate(pages[i]);
set_page_private(pages[i], 1);
page_cache_get(pages[i]);
}
head = page_buffers(pages[i]);
bh = head;
do {
err = btrfs_map_bh_to_logical(root, bh,
alloc_extent_start);
BUG_ON(err);
if (err)
goto failed_truncate;
bh = bh->b_this_page;
if (alloc_extent_start)
alloc_extent_start++;
} while (bh != head);
pos += this_write;
WARN_ON(this_write > write_bytes);
write_bytes -= this_write;
}
return 0;
failed_release:
btrfs_drop_pages(pages, num_pages);
return err;
failed_truncate:
btrfs_drop_pages(pages, num_pages);
if (pos > isize)
vmtruncate(inode, isize);
return err;
out_unlock:
mutex_unlock(&root->fs_info->fs_mutex);
goto failed_release;
}
static ssize_t btrfs_file_write(struct file *file, const char __user *buf,
......@@ -685,7 +667,6 @@ static ssize_t btrfs_file_write(struct file *file, const char __user *buf,
page_cache_release(pinned[1]);
*ppos = pos;
current->backing_dev_info = NULL;
mark_inode_dirty(inode);
return num_written ? num_written : err;
}
......@@ -714,8 +695,8 @@ static int btrfs_sync_file(struct file *file,
mutex_unlock(&root->fs_info->trans_mutex);
/*
* ok we haven't committed the transaction yet, lets do a commit
*/
* ok we haven't committed the transaction yet, lets do a commit
*/
trans = btrfs_start_transaction(root, 1);
if (!trans) {
ret = -ENOMEM;
......
fs/btrfs/inode.c
View file @ a52d9a80
......@@ -121,6 +121,8 @@ void btrfs_read_locked_inode(struct inode *inode)
switch (inode->i_mode & S_IFMT) {
case S_IFREG:
inode->i_mapping->a_ops = &btrfs_aops;
extent_map_tree_init(&BTRFS_I(inode)->extent_tree,
inode->i_mapping, GFP_NOFS);
inode->i_fop = &btrfs_file_operations;
inode->i_op = &btrfs_file_inode_operations;
break;
......@@ -169,7 +171,7 @@ static void fill_inode_item(struct btrfs_inode_item *item,
BTRFS_I(inode)->block_group->key.objectid);
}
static int btrfs_update_inode(struct btrfs_trans_handle *trans,
int btrfs_update_inode(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
struct inode *inode)
{
......@@ -400,6 +402,7 @@ static int btrfs_truncate_in_trans(struct btrfs_trans_handle *trans,
int found_extent;
int del_item;
btrfs_drop_extent_cache(inode, inode->i_size, (u64)-1);
path = btrfs_alloc_path();
path->reada = -1;
BUG_ON(!path);
......@@ -511,6 +514,50 @@ static int btrfs_truncate_in_trans(struct btrfs_trans_handle *trans,
return ret;
}
static int btrfs_cow_one_page(struct btrfs_trans_handle *trans,
struct inode *inode, struct page *page,
size_t zero_start)
{
char *kaddr;
int ret = 0;
struct btrfs_root *root = BTRFS_I(inode)->root;
u64 alloc_hint = 0;
u64 page_start = page->index << PAGE_CACHE_SHIFT;
struct btrfs_key ins;
if (!PagePrivate(page)) {
SetPagePrivate(page);
set_page_private(page, 1);
page_cache_get(page);
}
btrfs_set_trans_block_group(trans, inode);
ret = btrfs_drop_extents(trans, root, inode,
page_start, page_start + PAGE_CACHE_SIZE,
&alloc_hint);
if (ret)
goto out;
ret = btrfs_alloc_extent(trans, root, inode->i_ino, 1, 0,
alloc_hint, (u64)-1, &ins, 1);
if (ret)
goto out;
ret = btrfs_insert_file_extent(trans, root, inode->i_ino,
page_start, ins.objectid, 1, 1);
if (ret)
goto out;
SetPageChecked(page);
kaddr = kmap(page);
if (zero_start != PAGE_CACHE_SIZE) {
memset(kaddr + zero_start, 0, PAGE_CACHE_SIZE - zero_start);
flush_dcache_page(page);
}
kunmap(page);
out:
return ret;
}
/*
* taken from block_truncate_page, but does cow as it zeros out
* any bytes left in the last page in the file.
......@@ -518,16 +565,14 @@ static int btrfs_truncate_in_trans(struct btrfs_trans_handle *trans,
static int btrfs_truncate_page(struct address_space *mapping, loff_t from)
{
struct inode *inode = mapping->host;
struct btrfs_root *root = BTRFS_I(inode)->root;
struct btrfs_trans_handle *trans;
unsigned blocksize = 1 << inode->i_blkbits;
pgoff_t index = from >> PAGE_CACHE_SHIFT;
unsigned offset = from & (PAGE_CACHE_SIZE-1);
struct page *page;
char *kaddr;
int ret = 0;
struct btrfs_root *root = BTRFS_I(inode)->root;
u64 alloc_hint = 0;
struct btrfs_key ins;
struct btrfs_trans_handle *trans;
u64 page_start;
if ((offset & (blocksize - 1)) == 0)
goto out;
......@@ -536,7 +581,6 @@ static int btrfs_truncate_page(struct address_space *mapping, loff_t from)
page = grab_cache_page(mapping, index);
if (!page)
goto out;
if (!PageUptodate(page)) {
ret = btrfs_readpage(NULL, page);
lock_page(page);
......@@ -545,37 +589,24 @@ static int btrfs_truncate_page(struct address_space *mapping, loff_t from)
goto out;
}
}
page_start = page->index << PAGE_CACHE_SHIFT;
mutex_lock(&root->fs_info->fs_mutex);
trans = btrfs_start_transaction(root, 1);
btrfs_set_trans_block_group(trans, inode);
ret = btrfs_drop_extents(trans, root, inode,
page->index << PAGE_CACHE_SHIFT,
(page->index + 1) << PAGE_CACHE_SHIFT,
&alloc_hint);
if (ret)
goto out;
ret = btrfs_alloc_extent(trans, root, inode->i_ino, 1, 0,
alloc_hint, (u64)-1, &ins, 1);
if (ret)
goto out;
ret = btrfs_insert_file_extent(trans, root, inode->i_ino,
page->index << PAGE_CACHE_SHIFT,
ins.objectid, 1, 1);
if (ret)
goto out;
SetPageChecked(page);
kaddr = kmap(page);
memset(kaddr + offset, 0, PAGE_CACHE_SIZE - offset);
flush_dcache_page(page);
ret = btrfs_csum_file_block(trans, root, inode->i_ino,
page->index << PAGE_CACHE_SHIFT,
kaddr, PAGE_CACHE_SIZE);
kunmap(page);
ret = btrfs_cow_one_page(trans, inode, page, offset);
if (!ret) {
char *kaddr = kmap(page);
ret = btrfs_csum_file_block(trans, root, inode->i_ino,
page_start, kaddr, PAGE_CACHE_SIZE);
kunmap(page);
}
set_extent_dirty(&BTRFS_I(inode)->extent_tree,
page_start, page_start + PAGE_CACHE_SIZE - 1,
GFP_NOFS);
set_page_dirty(page);
btrfs_end_transaction(trans, root);
mutex_unlock(&root->fs_info->fs_mutex);
set_page_dirty(page);
unlock_page(page);
page_cache_release(page);
out:
......@@ -1095,6 +1126,8 @@ static int btrfs_create(struct inode *dir, struct dentry *dentry,
inode->i_mapping->a_ops = &btrfs_aops;
inode->i_fop = &btrfs_file_operations;
inode->i_op = &btrfs_file_inode_operations;
extent_map_tree_init(&BTRFS_I(inode)->extent_tree,
inode->i_mapping, GFP_NOFS);
}
dir->i_sb->s_dirt = 1;
btrfs_update_inode_block_group(trans, inode);
......@@ -1238,6 +1271,182 @@ static int btrfs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
return err;
}
struct extent_map *btrfs_get_extent(struct inode *inode, struct page *page,
size_t page_offset, u64 start, u64 end,
int create)
{
int ret;
int err = 0;
u64 blocknr;
u64 extent_start = 0;
u64 extent_end = 0;
u64 objectid = inode->i_ino;
u32 found_type;
int failed_insert = 0;
struct btrfs_path *path;
struct btrfs_root *root = BTRFS_I(inode)->root;
struct btrfs_file_extent_item *item;
struct btrfs_leaf *leaf;
struct btrfs_disk_key *found_key;
struct extent_map *em = NULL;
struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
struct btrfs_trans_handle *trans = NULL;
path = btrfs_alloc_path();
BUG_ON(!path);
mutex_lock(&root->fs_info->fs_mutex);
again:
em = lookup_extent_mapping(em_tree, start, end);
if (em) {
goto out;
}
if (!em) {
em = alloc_extent_map(GFP_NOFS);
if (!em) {
err = -ENOMEM;
goto out;
}
em->start = 0;
em->end = 0;
}
em->bdev = inode->i_sb->s_bdev;
ret = btrfs_lookup_file_extent(NULL, root, path,
objectid, start, 0);
if (ret < 0) {
err = ret;
goto out;
}
if (ret != 0) {
if (path->slots[0] == 0)
goto not_found;
path->slots[0]--;
}
item = btrfs_item_ptr(btrfs_buffer_leaf(path->nodes[0]), path->slots[0],
struct btrfs_file_extent_item);
leaf = btrfs_buffer_leaf(path->nodes[0]);
blocknr = btrfs_file_extent_disk_blocknr(item);
blocknr += btrfs_file_extent_offset(item);
/* are we inside the extent that was found? */
found_key = &leaf->items[path->slots[0]].key;
found_type = btrfs_disk_key_type(found_key);
if (btrfs_disk_key_objectid(found_key) != objectid ||
found_type != BTRFS_EXTENT_DATA_KEY) {
goto not_found;
}
found_type = btrfs_file_extent_type(item);
extent_start = btrfs_disk_key_offset(&leaf->items[path->slots[0]].key);
if (found_type == BTRFS_FILE_EXTENT_REG) {
extent_end = extent_start +
(btrfs_file_extent_num_blocks(item) << inode->i_blkbits);
err = 0;
if (start < extent_start || start > extent_end) {
em->start = start;
if (start < extent_start) {
em->end = extent_end - 1;
} else {
em->end = end;
}
goto not_found_em;
}
if (btrfs_file_extent_disk_blocknr(item) == 0) {
em->start = extent_start;
em->end = extent_end - 1;
em->block_start = 0;
em->block_end = 0;
goto insert;
}
em->block_start = blocknr << inode->i_blkbits;
em->block_end = em->block_start +
(btrfs_file_extent_num_blocks(item) <<
inode->i_blkbits) - 1;
em->start = extent_start;
em->end = extent_end - 1;
goto insert;
} else if (found_type == BTRFS_FILE_EXTENT_INLINE) {
char *ptr;
char *map;
u32 size;
size = btrfs_file_extent_inline_len(leaf->items +
path->slots[0]);
extent_end = extent_start + size;
if (start < extent_start || start > extent_end) {
em->start = start;
if (start < extent_start) {
em->end = extent_end - 1;
} else {
em->end = end;
}
goto not_found_em;
}
em->block_start = EXTENT_MAP_INLINE;
em->block_end = EXTENT_MAP_INLINE;
em->start = extent_start;
em->end = extent_end - 1;
if (!page) {
goto insert;
}
ptr = btrfs_file_extent_inline_start(item);
map = kmap(page);
memcpy(map + page_offset, ptr, size);
flush_dcache_page(result->b_page);
kunmap(page);
set_extent_uptodate(em_tree, extent_start,
extent_end, GFP_NOFS);
goto insert;
} else {
printk("unkknown found_type %d\n", found_type);
WARN_ON(1);
}
not_found:
em->start = start;
em->end = end;
not_found_em:
em->block_start = 0;
em->block_end = 0;
insert:
btrfs_release_path(root, path);
if (em->start > start || em->end < start) {
printk("bad extent! %Lu %Lu start %Lu end %Lu\n", em->start, em->end, start, end);
WARN_ON(1);
err = -EIO;
goto out;
}
ret = add_extent_mapping(em_tree, em);
if (ret == -EEXIST) {
free_extent_map(em);
failed_insert++;
if (failed_insert > 5) {
printk("failing to insert %Lu %Lu\n", start, end);
err = -EIO;
goto out;
}
em = NULL;
goto again;
}
err = 0;
out:
btrfs_free_path(path);
if (trans) {
ret = btrfs_end_transaction(trans, root);
if (!err)
err = ret;
}
mutex_unlock(&root->fs_info->fs_mutex);
if (err) {
free_extent_map(em);
WARN_ON(1);
return ERR_PTR(err);
}
return em;
}
/*
* FIBMAP and others want to pass in a fake buffer head. They need to
* use BTRFS_GET_BLOCK_NO_DIRECT to make sure we don't try to memcpy
......@@ -1398,46 +1607,22 @@ int btrfs_get_block(struct inode *inode, sector_t iblock,
return err;
}
static int btrfs_get_block_csum(struct inode *inode, sector_t iblock,
struct buffer_head *result, int create)
{
int ret;
struct btrfs_root *root = BTRFS_I(inode)->root;
struct page *page = result->b_page;
u64 offset = (page->index << PAGE_CACHE_SHIFT) + bh_offset(result);
struct btrfs_csum_item *item;
struct btrfs_path *path = NULL;
mutex_lock(&root->fs_info->fs_mutex);
ret = btrfs_get_block_lock(inode, iblock, result, create);
if (ret)
goto out;
path = btrfs_alloc_path();
item = btrfs_lookup_csum(NULL, root, path, inode->i_ino, offset, 0);
if (IS_ERR(item)) {
ret = PTR_ERR(item);
/* a csum that isn't present is a preallocated region. */
if (ret == -ENOENT || ret == -EFBIG)
ret = 0;
result->b_private = NULL;
goto out;
}
memcpy((char *)&result->b_private, &item->csum, BTRFS_CRC32_SIZE);
out:
if (path)
btrfs_free_path(path);
mutex_unlock(&root->fs_info->fs_mutex);
return ret;
}
static int btrfs_get_block_bmap(struct inode *inode, sector_t iblock,
struct buffer_head *result, int create)
{
struct btrfs_root *root = BTRFS_I(inode)->root;
mutex_lock(&root->fs_info->fs_mutex);
btrfs_get_block_lock(inode, iblock, result, BTRFS_GET_BLOCK_NO_DIRECT);
mutex_unlock(&root->fs_info->fs_mutex);
u64 start = iblock << inode->i_blkbits;
u64 end = start + root->blocksize -1;
struct extent_map *em;
em = btrfs_get_extent(inode, NULL, 0, start, end, 0);
if (em && !IS_ERR(em) && em->block_start != EXTENT_MAP_INLINE &&
em->block_start != 0) {
u64 offset;
offset = start - em->start;
start = (em->block_start + offset) >> inode->i_blkbits;
btrfs_map_bh_to_logical(root, result, start);
}
return 0;
}
......@@ -1449,442 +1634,50 @@ static sector_t btrfs_bmap(struct address_space *as, sector_t block)
static int btrfs_prepare_write(struct file *file, struct page *page,
unsigned from, unsigned to)
{
return block_prepare_write(page, from, to, btrfs_get_block);
return extent_prepare_write(&BTRFS_I(page->mapping->host)->extent_tree,
page->mapping->host, page, from, to,
btrfs_get_extent);
}
static void buffer_io_error(struct buffer_head *bh)
int btrfs_readpage(struct file *file, struct page *page)
{
char b[BDEVNAME_SIZE];
printk(KERN_ERR "Buffer I/O error on device %s, logical block %Lu\n",
bdevname(bh->b_bdev, b),
(unsigned long long)bh->b_blocknr);
struct extent_map_tree *tree;
tree = &BTRFS_I(page->mapping->host)->extent_tree;
return extent_read_full_page(tree, page, btrfs_get_extent);
}
/*
* I/O completion handler for block_read_full_page() - pages
* which come unlocked at the end of I/O.
*/
static void btrfs_end_buffer_async_read(struct buffer_head *bh, int uptodate)
static int btrfs_writepage(struct page *page, struct writeback_control *wbc)
{
unsigned long flags;
struct buffer_head *first;
struct buffer_head *tmp;
struct page *page;
int page_uptodate = 1;
struct inode *inode;
int ret;
BUG_ON(!buffer_async_read(bh));
page = bh->b_page;
inode = page->mapping->host;
if (uptodate) {
void *kaddr;
struct btrfs_root *root = BTRFS_I(page->mapping->host)->root;
if (bh->b_private) {
char csum[BTRFS_CRC32_SIZE];
kaddr = kmap_atomic(page, KM_IRQ0);
ret = btrfs_csum_data(root, kaddr + bh_offset(bh),
bh->b_size, csum);
BUG_ON(ret);
if (memcmp(csum, &bh->b_private, BTRFS_CRC32_SIZE)) {
u64 offset;
offset = (page->index << PAGE_CACHE_SHIFT) +
bh_offset(bh);
printk("btrfs csum failed ino %lu off %llu\n",
page->mapping->host->i_ino,
(unsigned long long)offset);
memset(kaddr + bh_offset(bh), 1, bh->b_size);
flush_dcache_page(page);
}
kunmap_atomic(kaddr, KM_IRQ0);
}
set_buffer_uptodate(bh);
} else {
clear_buffer_uptodate(bh);
if (printk_ratelimit())
buffer_io_error(bh);
SetPageError(page);
}
/*
* Be _very_ careful from here on. Bad things can happen if
* two buffer heads end IO at almost the same time and both
* decide that the page is now completely done.
*/
first = page_buffers(page);
local_irq_save(flags);
bit_spin_lock(BH_Uptodate_Lock, &first->b_state);
clear_buffer_async_read(bh);
unlock_buffer(bh);
tmp = bh;
do {
if (!buffer_uptodate(tmp))
page_uptodate = 0;
if (buffer_async_read(tmp)) {
BUG_ON(!buffer_locked(tmp));
goto still_busy;
}
tmp = tmp->b_this_page;
} while (tmp != bh);
bit_spin_unlock(BH_Uptodate_Lock, &first->b_state);
local_irq_restore(flags);
/*
* If none of the buffers had errors and they are all
* uptodate then we can set the page uptodate.
*/
if (page_uptodate && !PageError(page))
SetPageUptodate(page);
unlock_page(page);
return;
still_busy:
bit_spin_unlock(BH_Uptodate_Lock, &first->b_state);
local_irq_restore(flags);
return;
struct extent_map_tree *tree;
tree = &BTRFS_I(page->mapping->host)->extent_tree;
return extent_write_full_page(tree, page, btrfs_get_extent, wbc);
}
/*
* Generic "read page" function for block devices that have the normal
* get_block functionality. This is most of the block device filesystems.
* Reads the page asynchronously --- the unlock_buffer() and
* set/clear_buffer_uptodate() functions propagate buffer state into the
* page struct once IO has completed.
*/
int btrfs_readpage(struct file *file, struct page *page)
static int btrfs_releasepage(struct page *page, gfp_t unused_gfp_flags)
{
struct inode *inode = page->mapping->host;
sector_t iblock, lblock;
struct buffer_head *bh, *head, *arr[MAX_BUF_PER_PAGE];
unsigned int blocksize;
int nr, i;
int fully_mapped = 1;
BUG_ON(!PageLocked(page));
blocksize = 1 << inode->i_blkbits;
if (!page_has_buffers(page))
create_empty_buffers(page, blocksize, 0);
head = page_buffers(page);
iblock = (sector_t)page->index << (PAGE_CACHE_SHIFT - inode->i_blkbits);
lblock = (i_size_read(inode)+blocksize-1) >> inode->i_blkbits;
bh = head;
nr = 0;
i = 0;
do {
if (buffer_uptodate(bh))
continue;
if (!buffer_mapped(bh)) {
int err = 0;
fully_mapped = 0;
if (iblock < lblock) {
WARN_ON(bh->b_size != blocksize);
err = btrfs_get_block_csum(inode, iblock,
bh, 0);
if (err)
SetPageError(page);
}
if (!buffer_mapped(bh)) {
void *kaddr = kmap_atomic(page, KM_USER0);
memset(kaddr + i * blocksize, 0, blocksize);
flush_dcache_page(page);
kunmap_atomic(kaddr, KM_USER0);
if (!err)
set_buffer_uptodate(bh);
continue;
}
/*
* get_block() might have updated the buffer
* synchronously
*/
if (buffer_uptodate(bh))
continue;
}
arr[nr++] = bh;
} while (i++, iblock++, (bh = bh->b_this_page) != head);
if (fully_mapped)
SetPageMappedToDisk(page);
if (!nr) {
/*
* All buffers are uptodate - we can set the page uptodate
* as well. But not if get_block() returned an error.
*/
if (!PageError(page))
SetPageUptodate(page);
unlock_page(page);
return 0;
}
/* Stage two: lock the buffers */
for (i = 0; i < nr; i++) {
bh = arr[i];
lock_buffer(bh);
bh->b_end_io = btrfs_end_buffer_async_read;
set_buffer_async_read(bh);
}
/*
* Stage 3: start the IO. Check for uptodateness
* inside the buffer lock in case another process reading
* the underlying blockdev brought it uptodate (the sct fix).
*/
for (i = 0; i < nr; i++) {
bh = arr[i];
if (buffer_uptodate(bh))
btrfs_end_buffer_async_read(bh, 1);
else
submit_bh(READ, bh);
}
return 0;
}
/*
* Aside from a tiny bit of packed file data handling, this is the
* same as the generic code.
*
* While block_write_full_page is writing back the dirty buffers under
* the page lock, whoever dirtied the buffers may decide to clean them
* again at any time. We handle that by only looking at the buffer
* state inside lock_buffer().
*
* If block_write_full_page() is called for regular writeback
* (wbc->sync_mode == WB_SYNC_NONE) then it will redirty a page which has a
* locked buffer. This only can happen if someone has written the buffer
* directly, with submit_bh(). At the address_space level PageWriteback
* prevents this contention from occurring.
*/
static int __btrfs_write_full_page(struct inode *inode, struct page *page,
struct writeback_control *wbc)
{
int err;
sector_t block;
sector_t last_block;
struct buffer_head *bh, *head;
const unsigned blocksize = 1 << inode->i_blkbits;
int nr_underway = 0;
struct btrfs_root *root = BTRFS_I(inode)->root;
BUG_ON(!PageLocked(page));
last_block = (i_size_read(inode) - 1) >> inode->i_blkbits;
/* no csumming allowed when from PF_MEMALLOC */
if (current->flags & PF_MEMALLOC) {
redirty_page_for_writepage(wbc, page);
unlock_page(page);
return 0;
}
struct extent_map_tree *tree;
int ret;
if (!page_has_buffers(page)) {
create_empty_buffers(page, blocksize,
(1 << BH_Dirty)|(1 << BH_Uptodate));
if (page->private != 1) {
WARN_ON(1);
return try_to_free_buffers(page);
}
/*
* Be very careful. We have no exclusion from __set_page_dirty_buffers
* here, and the (potentially unmapped) buffers may become dirty at
* any time. If a buffer becomes dirty here after we've inspected it
* then we just miss that fact, and the page stays dirty.
*
* Buffers outside i_size may be dirtied by __set_page_dirty_buffers;
* handle that here by just cleaning them.
*/
block = (sector_t)page->index << (PAGE_CACHE_SHIFT - inode->i_blkbits);
head = page_buffers(page);
bh = head;
/*
* Get all the dirty buffers mapped to disk addresses and
* handle any aliases from the underlying blockdev's mapping.
*/
do {
if (block > last_block) {
/*
* mapped buffers outside i_size will occur, because
* this page can be outside i_size when there is a
* truncate in progress.
*/
/*
* The buffer was zeroed by block_write_full_page()
*/
clear_buffer_dirty(bh);
set_buffer_uptodate(bh);
} else if (!buffer_mapped(bh) && buffer_dirty(bh)) {
WARN_ON(bh->b_size != blocksize);
err = btrfs_get_block(inode, block, bh, 0);
if (err) {
goto recover;
}
if (buffer_new(bh)) {
/* blockdev mappings never come here */
clear_buffer_new(bh);
}
}
bh = bh->b_this_page;
block++;
} while (bh != head);
do {
if (!buffer_mapped(bh))
continue;
/*
* If it's a fully non-blocking write attempt and we cannot
* lock the buffer then redirty the page. Note that this can
* potentially cause a busy-wait loop from pdflush and kswapd
* activity, but those code paths have their own higher-level
* throttling.
*/
if (wbc->sync_mode != WB_SYNC_NONE || !wbc->nonblocking) {
lock_buffer(bh);
} else if (test_set_buffer_locked(bh)) {
redirty_page_for_writepage(wbc, page);
continue;
}
if (test_clear_buffer_dirty(bh) && bh->b_blocknr != 0) {
struct btrfs_trans_handle *trans;
int ret;
u64 off = page->index << PAGE_CACHE_SHIFT;
char *kaddr;
off += bh_offset(bh);
mutex_lock(&root->fs_info->fs_mutex);
trans = btrfs_start_transaction(root, 1);
btrfs_set_trans_block_group(trans, inode);
kaddr = kmap(page);
btrfs_csum_file_block(trans, root, inode->i_ino,
off, kaddr + bh_offset(bh),
bh->b_size);
kunmap(page);
ret = btrfs_end_transaction(trans, root);
BUG_ON(ret);
mutex_unlock(&root->fs_info->fs_mutex);
mark_buffer_async_write(bh);
} else {
unlock_buffer(bh);
}
} while ((bh = bh->b_this_page) != head);
/*
* The page and its buffers are protected by PageWriteback(), so we can
* drop the bh refcounts early.
*/
BUG_ON(PageWriteback(page));
set_page_writeback(page);
do {
struct buffer_head *next = bh->b_this_page;
if (buffer_async_write(bh)) {
submit_bh(WRITE, bh);
nr_underway++;
}
bh = next;
} while (bh != head);
unlock_page(page);
err = 0;
done:
if (nr_underway == 0) {
/*
* The page was marked dirty, but the buffers were
* clean. Someone wrote them back by hand with
* ll_rw_block/submit_bh. A rare case.
*/
int uptodate = 1;
do {
if (!buffer_uptodate(bh)) {
uptodate = 0;
break;
}
bh = bh->b_this_page;
} while (bh != head);
if (uptodate)
SetPageUptodate(page);
end_page_writeback(page);
tree = &BTRFS_I(page->mapping->host)->extent_tree;
ret = try_release_extent_mapping(tree, page);
if (ret == 1) {
ClearPagePrivate(page);
set_page_private(page, 0);
page_cache_release(page);
}
return err;
recover:
/*
* ENOSPC, or some other error. We may already have added some
* blocks to the file, so we need to write these out to avoid
* exposing stale data.
* The page is currently locked and not marked for writeback
*/
bh = head;
/* Recovery: lock and submit the mapped buffers */
do {
if (buffer_mapped(bh) && buffer_dirty(bh)) {
lock_buffer(bh);
mark_buffer_async_write(bh);
} else {
/*
* The buffer may have been set dirty during
* attachment to a dirty page.
*/
clear_buffer_dirty(bh);
}
} while ((bh = bh->b_this_page) != head);
SetPageError(page);
BUG_ON(PageWriteback(page));
set_page_writeback(page);
do {
struct buffer_head *next = bh->b_this_page;
if (buffer_async_write(bh)) {
clear_buffer_dirty(bh);
submit_bh(WRITE, bh);
nr_underway++;
}
bh = next;
} while (bh != head);
unlock_page(page);
goto done;
return ret;
}
static int btrfs_writepage(struct page *page, struct writeback_control *wbc)
static void btrfs_invalidatepage(struct page *page, unsigned long offset)
{
struct inode * const inode = page->mapping->host;
loff_t i_size = i_size_read(inode);
const pgoff_t end_index = i_size >> PAGE_CACHE_SHIFT;
unsigned offset;
void *kaddr;
/* Is the page fully inside i_size? */
if (page->index < end_index)
return __btrfs_write_full_page(inode, page, wbc);
/* Is the page fully outside i_size? (truncate in progress) */
offset = i_size & (PAGE_CACHE_SIZE-1);
if (page->index >= end_index+1 || !offset) {
/*
* The page may have dirty, unmapped buffers. For example,
* they may have been added in ext3_writepage(). Make them
* freeable here, so the page does not leak.
*/
block_invalidatepage(page, 0);
unlock_page(page);
return 0; /* don't care */
}
struct extent_map_tree *tree;
/*
* The page straddles i_size. It must be zeroed out on each and every
* writepage invokation because it may be mmapped. "A file is mapped
* in multiples of the page size. For a file that is not a multiple of
* the page size, the remaining memory is zeroed when mapped, and
* writes to that region are not written out to the file."
*/
kaddr = kmap_atomic(page, KM_USER0);
memset(kaddr + offset, 0, PAGE_CACHE_SIZE - offset);
flush_dcache_page(page);
kunmap_atomic(kaddr, KM_USER0);
return __btrfs_write_full_page(inode, page, wbc);
tree = &BTRFS_I(page->mapping->host)->extent_tree;
extent_invalidatepage(tree, page, offset);
btrfs_releasepage(page, GFP_NOFS);
}
/*
......@@ -1905,28 +1698,39 @@ static int btrfs_writepage(struct page *page, struct writeback_control *wbc)
int btrfs_page_mkwrite(struct vm_area_struct *vma, struct page *page)
{
struct inode *inode = vma->vm_file->f_path.dentry->d_inode;
struct btrfs_root *root = BTRFS_I(inode)->root;
struct btrfs_trans_handle *trans;
unsigned long end;
loff_t size;
int ret = -EINVAL;
u64 page_start;
lock_page(page);
wait_on_page_writeback(page);
size = i_size_read(inode);
page_start = page->index << PAGE_CACHE_SHIFT;
if ((page->mapping != inode->i_mapping) ||
((page->index << PAGE_CACHE_SHIFT) > size)) {
(page_start > size)) {
/* page got truncated out from underneath us */
goto out_unlock;
}
/* page is wholly or partially inside EOF */
if (((page->index + 1) << PAGE_CACHE_SHIFT) > size)
if (page_start + PAGE_CACHE_SIZE > size)
end = size & ~PAGE_CACHE_MASK;
else
end = PAGE_CACHE_SIZE;
ret = btrfs_prepare_write(NULL, page, 0, end);
if (!ret)
ret = btrfs_commit_write(NULL, page, 0, end);
mutex_lock(&root->fs_info->fs_mutex);
trans = btrfs_start_transaction(root, 1);
ret = btrfs_cow_one_page(trans, inode, page, end);
btrfs_end_transaction(trans, root);
mutex_unlock(&root->fs_info->fs_mutex);
set_extent_dirty(&BTRFS_I(inode)->extent_tree,
page_start, page_start + PAGE_CACHE_SIZE - 1,
GFP_NOFS);
set_page_dirty(page);
out_unlock:
unlock_page(page);
......@@ -1962,21 +1766,8 @@ static void btrfs_truncate(struct inode *inode)
int btrfs_commit_write(struct file *file, struct page *page,
unsigned from, unsigned to)
{
struct inode *inode = page->mapping->host;
struct buffer_head *bh;
loff_t pos = ((loff_t)page->index << PAGE_CACHE_SHIFT) + to;
SetPageUptodate(page);
bh = page_buffers(page);
set_buffer_uptodate(bh);
if (buffer_mapped(bh) && bh->b_blocknr != 0) {
set_page_dirty(page);
}
if (pos > inode->i_size) {
i_size_write(inode, pos);
mark_inode_dirty(inode);
}
return 0;
return extent_commit_write(&BTRFS_I(page->mapping->host)->extent_tree,
page->mapping->host, page, from, to);
}
static int create_subvol(struct btrfs_root *root, char *name, int namelen)
......@@ -2471,6 +2262,8 @@ static int btrfs_symlink(struct inode *dir, struct dentry *dentry,
inode->i_mapping->a_ops = &btrfs_aops;
inode->i_fop = &btrfs_file_operations;
inode->i_op = &btrfs_file_inode_operations;
extent_map_tree_init(&BTRFS_I(inode)->extent_tree,
inode->i_mapping, GFP_NOFS);
}
dir->i_sb->s_dirt = 1;
btrfs_update_inode_block_group(trans, inode);
......@@ -2553,6 +2346,9 @@ static struct address_space_operations btrfs_aops = {
.prepare_write = btrfs_prepare_write,
.commit_write = btrfs_commit_write,
.bmap = btrfs_bmap,
.invalidatepage = btrfs_invalidatepage,
.releasepage = btrfs_releasepage,
.set_page_dirty = __set_page_dirty_nobuffers,
};
static struct address_space_operations btrfs_symlink_aops = {
......
fs/btrfs/super.c
View file @ a52d9a80
......@@ -185,6 +185,7 @@ static int __init init_btrfs_fs(void)
err = btrfs_init_cachep();
if (err)
return err;
extent_map_init();
return register_filesystem(&btrfs_fs_type);
}
......@@ -192,6 +193,7 @@ static void __exit exit_btrfs_fs(void)
{
btrfs_exit_transaction_sys();
btrfs_destroy_cachep();
extent_map_exit();
unregister_filesystem(&btrfs_fs_type);
}
......
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