Release 4.11 fs/btrfs/extent_map.c

#include <linux/err.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/hardirq.h>
#include "ctree.h"
#include "extent_map.h"
#include "compression.h"



static struct kmem_cache *extent_map_cache;



int __init extent_map_init(void)
{
	extent_map_cache = kmem_cache_create("btrfs_extent_map",
			sizeof(struct extent_map), 0,
			SLAB_MEM_SPREAD, NULL);
	if (!extent_map_cache)
		return -ENOMEM;
	return 0;
}

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13
33.33%
1
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Christoph Hellwig
3
7.69%
1
20.00%
David Sterba
1
2.56%
1
20.00%
Total
39
100.00%
5
100.00%



void extent_map_exit(void)
{
	kmem_cache_destroy(extent_map_cache);
}

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1
100.00%

/**
 * extent_map_tree_init - initialize extent map tree
 * @tree:               tree to initialize
 *
 * Initialize the extent tree @tree.  Should be called for each new inode
 * or other user of the extent_map interface.
 */


void extent_map_tree_init(struct extent_map_tree *tree)
{
	tree->map = RB_ROOT;
	INIT_LIST_HEAD(&tree->modified_extents);
	rwlock_init(&tree->lock);
}

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8
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1
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Eric Paris
1
3.12%
1
16.67%
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32
100.00%
6
100.00%

/**
 * alloc_extent_map - allocate new extent map structure
 *
 * Allocate a new extent_map structure.  The new structure is
 * returned with a reference count of one and needs to be
 * freed using free_extent_map()
 */


struct extent_map *alloc_extent_map(void)
{
	struct extent_map *em;
	em = kmem_cache_zalloc(extent_map_cache, GFP_NOFS);
	if (!em)
		return NULL;
	RB_CLEAR_NODE(&em->rb_node);
	em->flags = 0;
	em->compress_type = BTRFS_COMPRESS_NONE;
	em->generation = 0;
	atomic_set(&em->refs, 1);
	INIT_LIST_HEAD(&em->list);
	return em;
}

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49
62.82%
3
33.33%
Josef Bacik
15
19.23%
2
22.22%
Li Zefan
6
7.69%
1
11.11%
Filipe David Borba Manana
5
6.41%
1
11.11%
David Sterba
2
2.56%
1
11.11%
Tsutomu Itoh
1
1.28%
1
11.11%
Total
78
100.00%
9
100.00%

/**
 * free_extent_map - drop reference count of an extent_map
 * @em:         extent map being released
 *
 * Drops the reference out on @em by one and free the structure
 * if the reference count hits zero.
 */


void free_extent_map(struct extent_map *em)
{
	if (!em)
		return;
	WARN_ON(atomic_read(&em->refs) == 0);
	if (atomic_dec_and_test(&em->refs)) {
		WARN_ON(extent_map_in_tree(em));
		WARN_ON(!list_empty(&em->list));
		if (test_bit(EXTENT_FLAG_FS_MAPPING, &em->flags))
			kfree(em->map_lookup);
		kmem_cache_free(extent_map_cache, em);
	}
}

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53
60.92%
3
42.86%
Shilong Wang
18
20.69%
1
14.29%
Josef Bacik
12
13.79%
1
14.29%
Filipe David Borba Manana
3
3.45%
1
14.29%
Jeff Mahoney
1
1.15%
1
14.29%
Total
87
100.00%
7
100.00%

/* simple helper to do math around the end of an extent, handling wrap */


static u64 range_end(u64 start, u64 len)
{
	if (start + len < start)
		return (u64)-1;
	return start + len;
}

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32
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1
100.00%



static int tree_insert(struct rb_root *root, struct extent_map *em)
{
	struct rb_node **p = &root->rb_node;
	struct rb_node *parent = NULL;
	struct extent_map *entry = NULL;
	struct rb_node *orig_parent = NULL;
	u64 end = range_end(em->start, em->len);

	while (*p) {
		parent = *p;
		entry = rb_entry(parent, struct extent_map, rb_node);

		if (em->start < entry->start)
			p = &(*p)->rb_left;
		else if (em->start >= extent_map_end(entry))
			p = &(*p)->rb_right;
		else
			return -EEXIST;
	}

	orig_parent = parent;
	while (parent && em->start >= extent_map_end(entry)) {
		parent = rb_next(parent);
		entry = rb_entry(parent, struct extent_map, rb_node);
	}
	if (parent)
		if (end > entry->start && em->start < extent_map_end(entry))
			return -EEXIST;

	parent = orig_parent;
	entry = rb_entry(parent, struct extent_map, rb_node);
	while (parent && em->start < entry->start) {
		parent = rb_prev(parent);
		entry = rb_entry(parent, struct extent_map, rb_node);
	}
	if (parent)
		if (end > entry->start && em->start < extent_map_end(entry))
			return -EEXIST;

	rb_link_node(&em->rb_node, orig_parent, p);
	rb_insert_color(&em->rb_node, root);
	return 0;
}

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168
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33.33%
Chris Mason
127
43.05%
2
66.67%
Total
295
100.00%
3
100.00%

/*
 * search through the tree for an extent_map with a given offset.  If
 * it can't be found, try to find some neighboring extents
 */


static struct rb_node *__tree_search(struct rb_root *root, u64 offset,
				     struct rb_node **prev_ret,
				     struct rb_node **next_ret)
{
	struct rb_node *n = root->rb_node;
	struct rb_node *prev = NULL;
	struct rb_node *orig_prev = NULL;
	struct extent_map *entry;
	struct extent_map *prev_entry = NULL;

	while (n) {
		entry = rb_entry(n, struct extent_map, rb_node);
		prev = n;
		prev_entry = entry;

		if (offset < entry->start)
			n = n->rb_left;
		else if (offset >= extent_map_end(entry))
			n = n->rb_right;
		else
			return n;
	}

	if (prev_ret) {
		orig_prev = prev;
		while (prev && offset >= extent_map_end(prev_entry)) {
			prev = rb_next(prev);
			prev_entry = rb_entry(prev, struct extent_map, rb_node);
		}
		*prev_ret = prev;
		prev = orig_prev;
	}

	if (next_ret) {
		prev_entry = rb_entry(prev, struct extent_map, rb_node);
		while (prev && offset < prev_entry->start) {
			prev = rb_prev(prev);
			prev_entry = rb_entry(prev, struct extent_map, rb_node);
		}
		*next_ret = prev;
	}
	return NULL;
}

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Chris Mason
231
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3
100.00%
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231
100.00%
3
100.00%

/* check to see if two extent_map structs are adjacent and safe to merge */


static int mergable_maps(struct extent_map *prev, struct extent_map *next)
{
	if (test_bit(EXTENT_FLAG_PINNED, &prev->flags))
		return 0;

	/*
         * don't merge compressed extents, we need to know their
         * actual size
         */
	if (test_bit(EXTENT_FLAG_COMPRESSED, &prev->flags))
		return 0;

	if (test_bit(EXTENT_FLAG_LOGGING, &prev->flags) ||
	    test_bit(EXTENT_FLAG_LOGGING, &next->flags))
		return 0;

	/*
         * We don't want to merge stuff that hasn't been written to the log yet
         * since it may not reflect exactly what is on disk, and that would be
         * bad.
         */
	if (!list_empty(&prev->list) || !list_empty(&next->list))
		return 0;

	if (extent_map_end(prev) == next->start &&
	    prev->flags == next->flags &&
	    prev->bdev == next->bdev &&
	    ((next->block_start == EXTENT_MAP_HOLE &&
	      prev->block_start == EXTENT_MAP_HOLE) ||
	     (next->block_start == EXTENT_MAP_INLINE &&
	      prev->block_start == EXTENT_MAP_INLINE) ||
	     (next->block_start == EXTENT_MAP_DELALLOC &&
	      prev->block_start == EXTENT_MAP_DELALLOC) ||
	     (next->block_start < EXTENT_MAP_LAST_BYTE - 1 &&
	      next->block_start == extent_map_block_end(prev)))) {
		return 1;
	}
	return 0;
}

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145
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66.67%
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49
25.26%
2
33.33%
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194
100.00%
6
100.00%



static void try_merge_map(struct extent_map_tree *tree, struct extent_map *em)
{
	struct extent_map *merge = NULL;
	struct rb_node *rb;

	if (em->start != 0) {
		rb = rb_prev(&em->rb_node);
		if (rb)
			merge = rb_entry(rb, struct extent_map, rb_node);
		if (rb && mergable_maps(merge, em)) {
			em->start = merge->start;
			em->orig_start = merge->orig_start;
			em->len += merge->len;
			em->block_len += merge->block_len;
			em->block_start = merge->block_start;
			em->mod_len = (em->mod_len + em->mod_start) - merge->mod_start;
			em->mod_start = merge->mod_start;
			em->generation = max(em->generation, merge->generation);

			rb_erase(&merge->rb_node, &tree->map);
			RB_CLEAR_NODE(&merge->rb_node);
			free_extent_map(merge);
		}
	}

	rb = rb_next(&em->rb_node);
	if (rb)
		merge = rb_entry(rb, struct extent_map, rb_node);
	if (rb && mergable_maps(em, merge)) {
		em->len += merge->len;
		em->block_len += merge->block_len;
		rb_erase(&merge->rb_node, &tree->map);
		RB_CLEAR_NODE(&merge->rb_node);
		em->mod_len = (merge->mod_start + merge->mod_len) - em->mod_start;
		em->generation = max(em->generation, merge->generation);
		free_extent_map(merge);
	}
}

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194
65.10%
1
14.29%
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65
21.81%
2
28.57%
Liu Bo
17
5.70%
1
14.29%
Filipe David Borba Manana
14
4.70%
2
28.57%
Li Zefan
8
2.68%
1
14.29%
Total
298
100.00%
7
100.00%

/**
 * unpin_extent_cache - unpin an extent from the cache
 * @tree:       tree to unpin the extent in
 * @start:      logical offset in the file
 * @len:        length of the extent
 * @gen:        generation that this extent has been modified in
 *
 * Called after an extent has been written to disk properly.  Set the generation
 * to the generation that actually added the file item to the inode so we know
 * we need to sync this extent when we call fsync().
 */


int unpin_extent_cache(struct extent_map_tree *tree, u64 start, u64 len,
		       u64 gen)
{
	int ret = 0;
	struct extent_map *em;
	bool prealloc = false;

	write_lock(&tree->lock);
	em = lookup_extent_mapping(tree, start, len);

	WARN_ON(!em || em->start != start);

	if (!em)
		goto out;

	em->generation = gen;
	clear_bit(EXTENT_FLAG_PINNED, &em->flags);
	em->mod_start = em->start;
	em->mod_len = em->len;

	if (test_bit(EXTENT_FLAG_FILLING, &em->flags)) {
		prealloc = true;
		clear_bit(EXTENT_FLAG_FILLING, &em->flags);
	}

	try_merge_map(tree, em);

	if (prealloc) {
		em->mod_start = em->start;
		em->mod_len = em->len;
	}

	free_extent_map(em);
out:
	write_unlock(&tree->lock);
	return ret;

}

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81
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1
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69
38.33%
1
20.00%
Chris Mason
19
10.56%
1
20.00%
Josef Bacik
11
6.11%
2
40.00%
Total
180
100.00%
5
100.00%



void clear_em_logging(struct extent_map_tree *tree, struct extent_map *em)
{
	clear_bit(EXTENT_FLAG_LOGGING, &em->flags);
	if (extent_map_in_tree(em))
		try_merge_map(tree, em);
}

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36
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3
7.69%
1
33.33%
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39
100.00%
3
100.00%



static inline void setup_extent_mapping(struct extent_map_tree *tree,
					struct extent_map *em,
					int modified)
{
	atomic_inc(&em->refs);
	em->mod_start = em->start;
	em->mod_len = em->len;

	if (modified)
		list_move(&em->list, &tree->modified_extents);
	else
		try_merge_map(tree, em);
}

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26
37.68%
2
33.33%
Josef Bacik
21
30.43%
1
16.67%
Liu Bo
16
23.19%
1
16.67%
Filipe David Borba Manana
5
7.25%
1
16.67%
Li Zefan
1
1.45%
1
16.67%
Total
69
100.00%
6
100.00%

/**
 * add_extent_mapping - add new extent map to the extent tree
 * @tree:       tree to insert new map in
 * @em:         map to insert
 *
 * Insert @em into @tree or perform a simple forward/backward merge with
 * existing mappings.  The extent_map struct passed in will be inserted
 * into the tree directly, with an additional reference taken, or a
 * reference dropped if the merge attempt was successful.
 */


int add_extent_mapping(struct extent_map_tree *tree,
		       struct extent_map *em, int modified)
{
	int ret = 0;

	ret = tree_insert(&tree->map, em);
	if (ret)
		goto out;

	setup_extent_mapping(tree, em, modified);
out:
	return ret;
}

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66.67%
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56
100.00%
3
100.00%


static struct extent_map *

__lookup_extent_mapping(struct extent_map_tree *tree,
			u64 start, u64 len, int strict)
{
	struct extent_map *em;
	struct rb_node *rb_node;
	struct rb_node *prev = NULL;
	struct rb_node *next = NULL;
	u64 end = range_end(start, len);

	rb_node = __tree_search(&tree->map, start, &prev, &next);
	if (!rb_node) {
		if (prev)
			rb_node = prev;
		else if (next)
			rb_node = next;
		else
			return NULL;
	}

	em = rb_entry(rb_node, struct extent_map, rb_node);

	if (strict && !(end > em->start && start < extent_map_end(em)))
		return NULL;

	atomic_inc(&em->refs);
	return em;
}

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20
13.51%
1
20.00%
Eric Sandeen
1
0.68%
1
20.00%
Total
148
100.00%
5
100.00%

/**
 * lookup_extent_mapping - lookup extent_map
 * @tree:       tree to lookup in
 * @start:      byte offset to start the search
 * @len:        length of the lookup range
 *
 * Find and return the first extent_map struct in @tree that intersects the
 * [start, len] range.  There may be additional objects in the tree that
 * intersect, so check the object returned carefully to make sure that no
 * additional lookups are needed.
 */


struct extent_map *lookup_extent_mapping(struct extent_map_tree *tree,
					 u64 start, u64 len)
{
	return __lookup_extent_mapping(tree, start, len, 1);
}

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6
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1
50.00%
Total
30
100.00%
2
100.00%

/**
 * search_extent_mapping - find a nearby extent map
 * @tree:       tree to lookup in
 * @start:      byte offset to start the search
 * @len:        length of the lookup range
 *
 * Find and return the first extent_map struct in @tree that intersects the
 * [start, len] range.
 *
 * If one can't be found, any nearby extent may be returned
 */


struct extent_map *search_extent_mapping(struct extent_map_tree *tree,
					 u64 start, u64 len)
{
	return __lookup_extent_mapping(tree, start, len, 0);
}

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1
33.33%
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30
100.00%
3
100.00%

/**
 * remove_extent_mapping - removes an extent_map from the extent tree
 * @tree:       extent tree to remove from
 * @em:         extent map being removed
 *
 * Removes @em from @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 = 0;

	WARN_ON(test_bit(EXTENT_FLAG_PINNED, &em->flags));
	rb_erase(&em->rb_node, &tree->map);
	if (!test_bit(EXTENT_FLAG_LOGGING, &em->flags))
		list_del_init(&em->list);
	RB_CLEAR_NODE(&em->rb_node);
	return ret;
}

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Chris Mason
52
66.67%
3
50.00%
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21
26.92%
2
33.33%
Filipe David Borba Manana
5
6.41%
1
16.67%
Total
78
100.00%
6
100.00%



void replace_extent_mapping(struct extent_map_tree *tree,
			    struct extent_map *cur,
			    struct extent_map *new,
			    int modified)
{
	WARN_ON(test_bit(EXTENT_FLAG_PINNED, &cur->flags));
	ASSERT(extent_map_in_tree(cur));
	if (!test_bit(EXTENT_FLAG_LOGGING, &cur->flags))
		list_del_init(&cur->list);
	rb_replace_node(&cur->rb_node, &new->rb_node, &tree->map);
	RB_CLEAR_NODE(&cur->rb_node);

	setup_extent_mapping(tree, new, modified);
}
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100
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1
100.00%
Total
100
100.00%
1
100.00%

Overall Contributors
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Chris Mason
1140
55.18%
13
30.23%
Filipe David Borba Manana
387
18.73%
4
9.30%
Josef Bacik
238
11.52%
7
16.28%
Li Zefan
150
7.26%
4
9.30%
Liu Bo
103
4.99%
2
4.65%
Shilong Wang
18
0.87%
1
2.33%
Wyatt Banks
13
0.63%
1
2.33%
David Sterba
5
0.24%
3
6.98%
Anand Jain
3
0.15%
1
2.33%
Christoph Hellwig
3
0.15%
1
2.33%
Eric Paris
1
0.05%
1
2.33%
Tsutomu Itoh
1
0.05%
1
2.33%
Eric Sandeen
1
0.05%
1
2.33%
Nicholas D Steeves
1
0.05%
1
2.33%
Adam Buchbinder
1
0.05%
1
2.33%
Jeff Mahoney
1
0.05%
1
2.33%
Total
2066
100.00%
43
100.00%
Directory: fs/btrfs

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