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	Version: linux-6.0.1 spark-3.0.0 hadoop-3.2.0-src hadoop-3.3.0-src spark-2.4.7 linux-4.15.13 hadoop-2.7.4-src Revert   Change

 // SPDX-License-Identifier: GPL-2.0
 
 #include <linux/err.h>
 #include <linux/slab.h>
 #include <linux/spinlock.h>
 #include "ctree.h"
 #include "volumes.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;
 }
 
 void __cold extent_map_exit(void)
 {
     kmem_cache_destroy(extent_map_cache);
 }
 
 /**
  * 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_CACHED;
     INIT_LIST_HEAD(&tree->modified_extents);
     rwlock_init(&tree->lock);
 }
 
 /**
  * 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;
     refcount_set(&em->refs, 1);
     INIT_LIST_HEAD(&em->list);
     return em;
 }
 
 /**
  * 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(refcount_read(&em->refs) == 0);
     if (refcount_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);
     }
 }
 
 /* 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;
 }
 
 static int tree_insert(struct rb_root_cached *root, struct extent_map *em)
 {
     struct rb_node **p = &root->rb_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);
     bool leftmost = true;
 
     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;
             leftmost = false;
         } 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_cached(&em->rb_node, root, leftmost);
     return 0;
 }
 
 /*
  * 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;
 }
 
 /* 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;
 
     ASSERT(next->block_start != EXTENT_MAP_DELALLOC &&
            prev->block_start != EXTENT_MAP_DELALLOC);
 
     if (prev->map_lookup || next->map_lookup)
         ASSERT(test_bit(EXTENT_FLAG_FS_MAPPING, &prev->flags) &&
                test_bit(EXTENT_FLAG_FS_MAPPING, &next->flags));
 
     if (extent_map_end(prev) == next->start &&
         prev->flags == next->flags &&
         prev->map_lookup == next->map_lookup &&
         ((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_LAST_BYTE - 1 &&
           next->block_start == extent_map_block_end(prev)))) {
         return 1;
     }
     return 0;
 }
 
 static void try_merge_map(struct extent_map_tree *tree, struct extent_map *em)
 {
     struct extent_map *merge = NULL;
     struct rb_node *rb;
 
     /*
      * We can't modify an extent map that is in the tree and that is being
      * used by another task, as it can cause that other task to see it in
      * inconsistent state during the merging. We always have 1 reference for
      * the tree and 1 for this task (which is unpinning the extent map or
      * clearing the logging flag), so anything > 2 means it's being used by
      * other tasks too.
      */
     if (refcount_read(&em->refs) > 2)
         return;
 
     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);
             set_bit(EXTENT_FLAG_MERGED, &em->flags);
 
             rb_erase_cached(&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_cached(&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);
         set_bit(EXTENT_FLAG_MERGED, &em->flags);
         free_extent_map(merge);
     }
 }
 
 /**
  * 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;
 
 }
 
 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);
 }
 
 static inline void setup_extent_mapping(struct extent_map_tree *tree,
                     struct extent_map *em,
                     int modified)
 {
     refcount_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);
 }
 
 static void extent_map_device_set_bits(struct extent_map *em, unsigned bits)
 {
     struct map_lookup *map = em->map_lookup;
     u64 stripe_size = em->orig_block_len;
     int i;
 
     for (i = 0; i < map->num_stripes; i++) {
         struct btrfs_io_stripe *stripe = &map->stripes[i];
         struct btrfs_device *device = stripe->dev;
 
         set_extent_bits_nowait(&device->alloc_state, stripe->physical,
                  stripe->physical + stripe_size - 1, bits);
     }
 }
 
 static void extent_map_device_clear_bits(struct extent_map *em, unsigned bits)
 {
     struct map_lookup *map = em->map_lookup;
     u64 stripe_size = em->orig_block_len;
     int i;
 
     for (i = 0; i < map->num_stripes; i++) {
         struct btrfs_io_stripe *stripe = &map->stripes[i];
         struct btrfs_device *device = stripe->dev;
 
         __clear_extent_bit(&device->alloc_state, stripe->physical,
                    stripe->physical + stripe_size - 1, bits,
                    0, 0, NULL, GFP_NOWAIT, NULL);
     }
 }
 
 /**
  * Add new extent map to the extent tree
  *
  * @tree:   tree to insert new map in
  * @em:     map to insert
  * @modified:   indicate whether the given @em should be added to the
  *          modified list, which indicates the extent needs to be logged
  *
  * 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;
 
     lockdep_assert_held_write(&tree->lock);
 
     ret = tree_insert(&tree->map, em);
     if (ret)
         goto out;
 
     setup_extent_mapping(tree, em, modified);
     if (test_bit(EXTENT_FLAG_FS_MAPPING, &em->flags)) {
         extent_map_device_set_bits(em, CHUNK_ALLOCATED);
         extent_map_device_clear_bits(em, CHUNK_TRIMMED);
     }
 out:
     return ret;
 }
 
 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.rb_root, 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;
 
     refcount_inc(&em->refs);
     return em;
 }
 
 /**
  * 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);
 }
 
 /**
  * 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);
 }
 
 /**
  * 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
  */
 void remove_extent_mapping(struct extent_map_tree *tree, struct extent_map *em)
 {
     lockdep_assert_held_write(&tree->lock);
 
     WARN_ON(test_bit(EXTENT_FLAG_PINNED, &em->flags));
     rb_erase_cached(&em->rb_node, &tree->map);
     if (!test_bit(EXTENT_FLAG_LOGGING, &em->flags))
         list_del_init(&em->list);
     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)
 {
     lockdep_assert_held_write(&tree->lock);
 
     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;
 }

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