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![Qu Wenruo](/assets/img/avatar_default.png)
The structure btrfs_bio is used by two different sites: - bio->bi_private for mirror based profiles For those profiles (SINGLE/DUP/RAID1*/RAID10), this structures records how many mirrors are still pending, and save the original endio function of the bio. - RAID56 code In that case, RAID56 only utilize the stripes info, and no long uses that to trace the pending mirrors. So btrfs_bio is not always bind to a bio, and contains more info for IO context, thus renaming it will make the naming less confusing. Signed-off-by: Qu Wenruo <wqu@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
654 lines
17 KiB
C
654 lines
17 KiB
C
// SPDX-License-Identifier: GPL-2.0
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#include <linux/err.h>
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#include <linux/slab.h>
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#include <linux/spinlock.h>
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#include "ctree.h"
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#include "volumes.h"
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#include "extent_map.h"
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#include "compression.h"
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static struct kmem_cache *extent_map_cache;
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int __init extent_map_init(void)
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{
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extent_map_cache = kmem_cache_create("btrfs_extent_map",
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sizeof(struct extent_map), 0,
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SLAB_MEM_SPREAD, NULL);
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if (!extent_map_cache)
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return -ENOMEM;
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return 0;
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}
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void __cold extent_map_exit(void)
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{
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kmem_cache_destroy(extent_map_cache);
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}
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/**
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* extent_map_tree_init - initialize extent map tree
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* @tree: tree to initialize
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*
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* Initialize the extent tree @tree. Should be called for each new inode
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* or other user of the extent_map interface.
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*/
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void extent_map_tree_init(struct extent_map_tree *tree)
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{
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tree->map = RB_ROOT_CACHED;
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INIT_LIST_HEAD(&tree->modified_extents);
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rwlock_init(&tree->lock);
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}
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/**
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* alloc_extent_map - allocate new extent map structure
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*
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* Allocate a new extent_map structure. The new structure is
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* returned with a reference count of one and needs to be
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* freed using free_extent_map()
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*/
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struct extent_map *alloc_extent_map(void)
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{
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struct extent_map *em;
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em = kmem_cache_zalloc(extent_map_cache, GFP_NOFS);
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if (!em)
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return NULL;
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RB_CLEAR_NODE(&em->rb_node);
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em->flags = 0;
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em->compress_type = BTRFS_COMPRESS_NONE;
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em->generation = 0;
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refcount_set(&em->refs, 1);
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INIT_LIST_HEAD(&em->list);
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return em;
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}
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/**
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* free_extent_map - drop reference count of an extent_map
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* @em: extent map being released
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*
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* Drops the reference out on @em by one and free the structure
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* if the reference count hits zero.
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*/
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void free_extent_map(struct extent_map *em)
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{
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if (!em)
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return;
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WARN_ON(refcount_read(&em->refs) == 0);
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if (refcount_dec_and_test(&em->refs)) {
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WARN_ON(extent_map_in_tree(em));
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WARN_ON(!list_empty(&em->list));
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if (test_bit(EXTENT_FLAG_FS_MAPPING, &em->flags))
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kfree(em->map_lookup);
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kmem_cache_free(extent_map_cache, em);
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}
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}
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/* simple helper to do math around the end of an extent, handling wrap */
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static u64 range_end(u64 start, u64 len)
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{
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if (start + len < start)
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return (u64)-1;
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return start + len;
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}
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static int tree_insert(struct rb_root_cached *root, struct extent_map *em)
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{
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struct rb_node **p = &root->rb_root.rb_node;
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struct rb_node *parent = NULL;
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struct extent_map *entry = NULL;
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struct rb_node *orig_parent = NULL;
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u64 end = range_end(em->start, em->len);
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bool leftmost = true;
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while (*p) {
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parent = *p;
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entry = rb_entry(parent, struct extent_map, rb_node);
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if (em->start < entry->start) {
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p = &(*p)->rb_left;
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} else if (em->start >= extent_map_end(entry)) {
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p = &(*p)->rb_right;
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leftmost = false;
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} else {
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return -EEXIST;
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}
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}
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orig_parent = parent;
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while (parent && em->start >= extent_map_end(entry)) {
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parent = rb_next(parent);
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entry = rb_entry(parent, struct extent_map, rb_node);
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}
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if (parent)
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if (end > entry->start && em->start < extent_map_end(entry))
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return -EEXIST;
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parent = orig_parent;
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entry = rb_entry(parent, struct extent_map, rb_node);
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while (parent && em->start < entry->start) {
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parent = rb_prev(parent);
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entry = rb_entry(parent, struct extent_map, rb_node);
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}
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if (parent)
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if (end > entry->start && em->start < extent_map_end(entry))
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return -EEXIST;
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rb_link_node(&em->rb_node, orig_parent, p);
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rb_insert_color_cached(&em->rb_node, root, leftmost);
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return 0;
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}
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/*
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* search through the tree for an extent_map with a given offset. If
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* it can't be found, try to find some neighboring extents
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*/
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static struct rb_node *__tree_search(struct rb_root *root, u64 offset,
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struct rb_node **prev_ret,
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struct rb_node **next_ret)
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{
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struct rb_node *n = root->rb_node;
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struct rb_node *prev = NULL;
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struct rb_node *orig_prev = NULL;
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struct extent_map *entry;
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struct extent_map *prev_entry = NULL;
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while (n) {
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entry = rb_entry(n, struct extent_map, rb_node);
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prev = n;
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prev_entry = entry;
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if (offset < entry->start)
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n = n->rb_left;
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else if (offset >= extent_map_end(entry))
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n = n->rb_right;
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else
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return n;
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}
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if (prev_ret) {
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orig_prev = prev;
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while (prev && offset >= extent_map_end(prev_entry)) {
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prev = rb_next(prev);
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prev_entry = rb_entry(prev, struct extent_map, rb_node);
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}
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*prev_ret = prev;
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prev = orig_prev;
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}
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if (next_ret) {
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prev_entry = rb_entry(prev, struct extent_map, rb_node);
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while (prev && offset < prev_entry->start) {
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prev = rb_prev(prev);
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prev_entry = rb_entry(prev, struct extent_map, rb_node);
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}
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*next_ret = prev;
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}
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return NULL;
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}
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/* check to see if two extent_map structs are adjacent and safe to merge */
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static int mergable_maps(struct extent_map *prev, struct extent_map *next)
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{
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if (test_bit(EXTENT_FLAG_PINNED, &prev->flags))
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return 0;
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/*
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* don't merge compressed extents, we need to know their
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* actual size
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*/
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if (test_bit(EXTENT_FLAG_COMPRESSED, &prev->flags))
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return 0;
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if (test_bit(EXTENT_FLAG_LOGGING, &prev->flags) ||
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test_bit(EXTENT_FLAG_LOGGING, &next->flags))
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return 0;
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/*
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* We don't want to merge stuff that hasn't been written to the log yet
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* since it may not reflect exactly what is on disk, and that would be
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* bad.
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*/
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if (!list_empty(&prev->list) || !list_empty(&next->list))
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return 0;
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ASSERT(next->block_start != EXTENT_MAP_DELALLOC &&
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prev->block_start != EXTENT_MAP_DELALLOC);
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if (prev->map_lookup || next->map_lookup)
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ASSERT(test_bit(EXTENT_FLAG_FS_MAPPING, &prev->flags) &&
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test_bit(EXTENT_FLAG_FS_MAPPING, &next->flags));
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if (extent_map_end(prev) == next->start &&
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prev->flags == next->flags &&
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prev->map_lookup == next->map_lookup &&
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((next->block_start == EXTENT_MAP_HOLE &&
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prev->block_start == EXTENT_MAP_HOLE) ||
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(next->block_start == EXTENT_MAP_INLINE &&
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prev->block_start == EXTENT_MAP_INLINE) ||
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(next->block_start < EXTENT_MAP_LAST_BYTE - 1 &&
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next->block_start == extent_map_block_end(prev)))) {
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return 1;
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}
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return 0;
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}
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static void try_merge_map(struct extent_map_tree *tree, struct extent_map *em)
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{
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struct extent_map *merge = NULL;
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struct rb_node *rb;
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/*
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* We can't modify an extent map that is in the tree and that is being
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* used by another task, as it can cause that other task to see it in
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* inconsistent state during the merging. We always have 1 reference for
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* the tree and 1 for this task (which is unpinning the extent map or
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* clearing the logging flag), so anything > 2 means it's being used by
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* other tasks too.
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*/
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if (refcount_read(&em->refs) > 2)
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return;
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if (em->start != 0) {
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rb = rb_prev(&em->rb_node);
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if (rb)
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merge = rb_entry(rb, struct extent_map, rb_node);
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if (rb && mergable_maps(merge, em)) {
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em->start = merge->start;
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em->orig_start = merge->orig_start;
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em->len += merge->len;
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em->block_len += merge->block_len;
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em->block_start = merge->block_start;
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em->mod_len = (em->mod_len + em->mod_start) - merge->mod_start;
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em->mod_start = merge->mod_start;
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em->generation = max(em->generation, merge->generation);
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rb_erase_cached(&merge->rb_node, &tree->map);
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RB_CLEAR_NODE(&merge->rb_node);
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free_extent_map(merge);
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}
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}
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rb = rb_next(&em->rb_node);
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if (rb)
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merge = rb_entry(rb, struct extent_map, rb_node);
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if (rb && mergable_maps(em, merge)) {
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em->len += merge->len;
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em->block_len += merge->block_len;
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rb_erase_cached(&merge->rb_node, &tree->map);
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RB_CLEAR_NODE(&merge->rb_node);
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em->mod_len = (merge->mod_start + merge->mod_len) - em->mod_start;
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em->generation = max(em->generation, merge->generation);
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free_extent_map(merge);
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}
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}
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/**
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* unpin_extent_cache - unpin an extent from the cache
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* @tree: tree to unpin the extent in
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* @start: logical offset in the file
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* @len: length of the extent
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* @gen: generation that this extent has been modified in
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*
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* Called after an extent has been written to disk properly. Set the generation
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* to the generation that actually added the file item to the inode so we know
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* we need to sync this extent when we call fsync().
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*/
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int unpin_extent_cache(struct extent_map_tree *tree, u64 start, u64 len,
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u64 gen)
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{
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int ret = 0;
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struct extent_map *em;
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bool prealloc = false;
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write_lock(&tree->lock);
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em = lookup_extent_mapping(tree, start, len);
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WARN_ON(!em || em->start != start);
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if (!em)
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goto out;
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em->generation = gen;
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clear_bit(EXTENT_FLAG_PINNED, &em->flags);
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em->mod_start = em->start;
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em->mod_len = em->len;
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if (test_bit(EXTENT_FLAG_FILLING, &em->flags)) {
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prealloc = true;
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clear_bit(EXTENT_FLAG_FILLING, &em->flags);
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}
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try_merge_map(tree, em);
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if (prealloc) {
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em->mod_start = em->start;
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em->mod_len = em->len;
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}
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free_extent_map(em);
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out:
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write_unlock(&tree->lock);
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return ret;
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}
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void clear_em_logging(struct extent_map_tree *tree, struct extent_map *em)
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{
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clear_bit(EXTENT_FLAG_LOGGING, &em->flags);
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if (extent_map_in_tree(em))
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try_merge_map(tree, em);
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}
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static inline void setup_extent_mapping(struct extent_map_tree *tree,
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struct extent_map *em,
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int modified)
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{
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refcount_inc(&em->refs);
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em->mod_start = em->start;
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em->mod_len = em->len;
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if (modified)
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list_move(&em->list, &tree->modified_extents);
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else
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try_merge_map(tree, em);
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}
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static void extent_map_device_set_bits(struct extent_map *em, unsigned bits)
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{
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struct map_lookup *map = em->map_lookup;
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u64 stripe_size = em->orig_block_len;
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int i;
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for (i = 0; i < map->num_stripes; i++) {
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struct btrfs_io_stripe *stripe = &map->stripes[i];
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struct btrfs_device *device = stripe->dev;
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set_extent_bits_nowait(&device->alloc_state, stripe->physical,
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stripe->physical + stripe_size - 1, bits);
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}
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}
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static void extent_map_device_clear_bits(struct extent_map *em, unsigned bits)
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{
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struct map_lookup *map = em->map_lookup;
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u64 stripe_size = em->orig_block_len;
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int i;
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for (i = 0; i < map->num_stripes; i++) {
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struct btrfs_io_stripe *stripe = &map->stripes[i];
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struct btrfs_device *device = stripe->dev;
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__clear_extent_bit(&device->alloc_state, stripe->physical,
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stripe->physical + stripe_size - 1, bits,
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0, 0, NULL, GFP_NOWAIT, NULL);
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}
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}
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/**
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* Add new extent map to the extent tree
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*
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* @tree: tree to insert new map in
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* @em: map to insert
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* @modified: indicate whether the given @em should be added to the
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* modified list, which indicates the extent needs to be logged
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*
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* Insert @em into @tree or perform a simple forward/backward merge with
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* existing mappings. The extent_map struct passed in will be inserted
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* into the tree directly, with an additional reference taken, or a
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* reference dropped if the merge attempt was successful.
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*/
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int add_extent_mapping(struct extent_map_tree *tree,
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struct extent_map *em, int modified)
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{
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int ret = 0;
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lockdep_assert_held_write(&tree->lock);
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ret = tree_insert(&tree->map, em);
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if (ret)
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goto out;
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setup_extent_mapping(tree, em, modified);
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if (test_bit(EXTENT_FLAG_FS_MAPPING, &em->flags)) {
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extent_map_device_set_bits(em, CHUNK_ALLOCATED);
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extent_map_device_clear_bits(em, CHUNK_TRIMMED);
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}
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out:
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return ret;
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}
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static struct extent_map *
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__lookup_extent_mapping(struct extent_map_tree *tree,
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u64 start, u64 len, int strict)
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{
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struct extent_map *em;
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struct rb_node *rb_node;
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struct rb_node *prev = NULL;
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struct rb_node *next = NULL;
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u64 end = range_end(start, len);
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rb_node = __tree_search(&tree->map.rb_root, start, &prev, &next);
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if (!rb_node) {
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if (prev)
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rb_node = prev;
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else if (next)
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rb_node = next;
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else
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return NULL;
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}
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em = rb_entry(rb_node, struct extent_map, rb_node);
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if (strict && !(end > em->start && start < extent_map_end(em)))
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return NULL;
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refcount_inc(&em->refs);
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return em;
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}
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/**
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* lookup_extent_mapping - lookup extent_map
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* @tree: tree to lookup in
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* @start: byte offset to start the search
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* @len: length of the lookup range
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*
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* Find and return the first extent_map struct in @tree that intersects the
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* [start, len] range. There may be additional objects in the tree that
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* intersect, so check the object returned carefully to make sure that no
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* additional lookups are needed.
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*/
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struct extent_map *lookup_extent_mapping(struct extent_map_tree *tree,
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u64 start, u64 len)
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{
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return __lookup_extent_mapping(tree, start, len, 1);
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}
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/**
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* search_extent_mapping - find a nearby extent map
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* @tree: tree to lookup in
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* @start: byte offset to start the search
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* @len: length of the lookup range
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*
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* Find and return the first extent_map struct in @tree that intersects the
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* [start, len] range.
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*
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* If one can't be found, any nearby extent may be returned
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*/
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struct extent_map *search_extent_mapping(struct extent_map_tree *tree,
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u64 start, u64 len)
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{
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return __lookup_extent_mapping(tree, start, len, 0);
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}
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/**
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* remove_extent_mapping - removes an extent_map from the extent tree
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* @tree: extent tree to remove from
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* @em: extent map being removed
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*
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* Removes @em from @tree. No reference counts are dropped, and no checks
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* are done to see if the range is in use
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*/
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void remove_extent_mapping(struct extent_map_tree *tree, struct extent_map *em)
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{
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WARN_ON(test_bit(EXTENT_FLAG_PINNED, &em->flags));
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rb_erase_cached(&em->rb_node, &tree->map);
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if (!test_bit(EXTENT_FLAG_LOGGING, &em->flags))
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list_del_init(&em->list);
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if (test_bit(EXTENT_FLAG_FS_MAPPING, &em->flags))
|
|
extent_map_device_clear_bits(em, CHUNK_ALLOCATED);
|
|
RB_CLEAR_NODE(&em->rb_node);
|
|
}
|
|
|
|
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_cached(&cur->rb_node, &new->rb_node, &tree->map);
|
|
RB_CLEAR_NODE(&cur->rb_node);
|
|
|
|
setup_extent_mapping(tree, new, modified);
|
|
}
|
|
|
|
static struct extent_map *next_extent_map(struct extent_map *em)
|
|
{
|
|
struct rb_node *next;
|
|
|
|
next = rb_next(&em->rb_node);
|
|
if (!next)
|
|
return NULL;
|
|
return container_of(next, struct extent_map, rb_node);
|
|
}
|
|
|
|
static struct extent_map *prev_extent_map(struct extent_map *em)
|
|
{
|
|
struct rb_node *prev;
|
|
|
|
prev = rb_prev(&em->rb_node);
|
|
if (!prev)
|
|
return NULL;
|
|
return container_of(prev, struct extent_map, rb_node);
|
|
}
|
|
|
|
/*
|
|
* Helper for btrfs_get_extent. Given an existing extent in the tree,
|
|
* the existing extent is the nearest extent to map_start,
|
|
* and an extent that you want to insert, deal with overlap and insert
|
|
* the best fitted new extent into the tree.
|
|
*/
|
|
static noinline int merge_extent_mapping(struct extent_map_tree *em_tree,
|
|
struct extent_map *existing,
|
|
struct extent_map *em,
|
|
u64 map_start)
|
|
{
|
|
struct extent_map *prev;
|
|
struct extent_map *next;
|
|
u64 start;
|
|
u64 end;
|
|
u64 start_diff;
|
|
|
|
BUG_ON(map_start < em->start || map_start >= extent_map_end(em));
|
|
|
|
if (existing->start > map_start) {
|
|
next = existing;
|
|
prev = prev_extent_map(next);
|
|
} else {
|
|
prev = existing;
|
|
next = next_extent_map(prev);
|
|
}
|
|
|
|
start = prev ? extent_map_end(prev) : em->start;
|
|
start = max_t(u64, start, em->start);
|
|
end = next ? next->start : extent_map_end(em);
|
|
end = min_t(u64, end, extent_map_end(em));
|
|
start_diff = start - em->start;
|
|
em->start = start;
|
|
em->len = end - start;
|
|
if (em->block_start < EXTENT_MAP_LAST_BYTE &&
|
|
!test_bit(EXTENT_FLAG_COMPRESSED, &em->flags)) {
|
|
em->block_start += start_diff;
|
|
em->block_len = em->len;
|
|
}
|
|
return add_extent_mapping(em_tree, em, 0);
|
|
}
|
|
|
|
/**
|
|
* Add extent mapping into em_tree
|
|
*
|
|
* @fs_info: the filesystem
|
|
* @em_tree: extent tree into which we want to insert the extent mapping
|
|
* @em_in: extent we are inserting
|
|
* @start: start of the logical range btrfs_get_extent() is requesting
|
|
* @len: length of the logical range btrfs_get_extent() is requesting
|
|
*
|
|
* Note that @em_in's range may be different from [start, start+len),
|
|
* but they must be overlapped.
|
|
*
|
|
* Insert @em_in into @em_tree. In case there is an overlapping range, handle
|
|
* the -EEXIST by either:
|
|
* a) Returning the existing extent in @em_in if @start is within the
|
|
* existing em.
|
|
* b) Merge the existing extent with @em_in passed in.
|
|
*
|
|
* Return 0 on success, otherwise -EEXIST.
|
|
*
|
|
*/
|
|
int btrfs_add_extent_mapping(struct btrfs_fs_info *fs_info,
|
|
struct extent_map_tree *em_tree,
|
|
struct extent_map **em_in, u64 start, u64 len)
|
|
{
|
|
int ret;
|
|
struct extent_map *em = *em_in;
|
|
|
|
ret = add_extent_mapping(em_tree, em, 0);
|
|
/* it is possible that someone inserted the extent into the tree
|
|
* while we had the lock dropped. It is also possible that
|
|
* an overlapping map exists in the tree
|
|
*/
|
|
if (ret == -EEXIST) {
|
|
struct extent_map *existing;
|
|
|
|
ret = 0;
|
|
|
|
existing = search_extent_mapping(em_tree, start, len);
|
|
|
|
trace_btrfs_handle_em_exist(fs_info, existing, em, start, len);
|
|
|
|
/*
|
|
* existing will always be non-NULL, since there must be
|
|
* extent causing the -EEXIST.
|
|
*/
|
|
if (start >= existing->start &&
|
|
start < extent_map_end(existing)) {
|
|
free_extent_map(em);
|
|
*em_in = existing;
|
|
ret = 0;
|
|
} else {
|
|
u64 orig_start = em->start;
|
|
u64 orig_len = em->len;
|
|
|
|
/*
|
|
* The existing extent map is the one nearest to
|
|
* the [start, start + len) range which overlaps
|
|
*/
|
|
ret = merge_extent_mapping(em_tree, existing,
|
|
em, start);
|
|
if (ret) {
|
|
free_extent_map(em);
|
|
*em_in = NULL;
|
|
WARN_ONCE(ret,
|
|
"unexpected error %d: merge existing(start %llu len %llu) with em(start %llu len %llu)\n",
|
|
ret, existing->start, existing->len,
|
|
orig_start, orig_len);
|
|
}
|
|
free_extent_map(existing);
|
|
}
|
|
}
|
|
|
|
ASSERT(ret == 0 || ret == -EEXIST);
|
|
return ret;
|
|
}
|