Any comments ?

于 2012-8-8 11:06, Chen Yang 写道:
> From: Chen Yang <[email protected]>
> 
> This patch adds the function to check correspondence
> between block group, chunk and device extent.
> 
> Signed-off-by: Cheng Yang <[email protected]>
> ---
> v1->v2: optimaze the checking process:
>       * Remove the checking traversal of block group RB tree.
>       * Mark block group item which matched with chunk item.
>       * Output the unmarked block group item error infomaton.
>         when releasing RB tree.
>       * Merge some relevant flows into one.
> ---
>  Makefile           |    2 +-
>  btrfsck.c          |  517 
> +++++++++++++++++++++++++++++++++++++++++++++++++++-
>  dev-extent-cache.c |  188 +++++++++++++++++++
>  dev-extent-cache.h |   60 ++++++
>  4 files changed, 760 insertions(+), 7 deletions(-)
>  create mode 100644 dev-extent-cache.c
>  create mode 100644 dev-extent-cache.h
> 
> diff --git a/Makefile b/Makefile
> index 9694444..75eced8 100644
> --- a/Makefile
> +++ b/Makefile
> @@ -4,7 +4,7 @@ CFLAGS = -g -O0
>  objects = ctree.o disk-io.o radix-tree.o extent-tree.o print-tree.o \
>         root-tree.o dir-item.o file-item.o inode-item.o \
>         inode-map.o crc32c.o rbtree.o extent-cache.o extent_io.o \
> -       volumes.o utils.o btrfs-list.o btrfslabel.o repair.o
> +       volumes.o utils.o btrfs-list.o btrfslabel.o repair.o 
> dev-extent-cache.o
>  cmds_objects = cmds-subvolume.o cmds-filesystem.o cmds-device.o cmds-scrub.o 
> \
>              cmds-inspect.o cmds-balance.o
>  
> diff --git a/btrfsck.c b/btrfsck.c
> index 088b9f4..437aee9 100644
> --- a/btrfsck.c
> +++ b/btrfsck.c
> @@ -34,6 +34,66 @@
>  #include "list.h"
>  #include "version.h"
>  #include "utils.h"
> +#include "dev-extent-cache.h"
> +
> +#define REC_UNCHECKED        0
> +#define REC_CHECKED  1
> +
> +struct block_group_record {
> +     struct cache_extent cache;
> +     int state;
> +
> +     u64 objectid;
> +     u8  type;
> +     u64 offset;
> +
> +     u64 flags;
> +};
> +
> +struct dev_record {
> +     struct cache_extent cache;
> +     int state;
> +
> +     u64 objectid;
> +     u8  type;
> +     u64 offset;
> +
> +     u64 devid;
> +     u64 total_byte;
> +     u64 byte_used;
> +};
> +
> +struct stripe {
> +     u64 devid;
> +     u64 offset;
> +};
> +
> +struct chunk_record {
> +     struct cache_extent cache;
> +     int state;
> +
> +     u64 objectid;
> +     u8  type;
> +     u64 offset;
> +
> +     u64 length;
> +     u64 type_flags;
> +     u16 num_stripes;
> +     struct stripe stripes[0];
> +};
> +
> +struct dev_extent_record {
> +     struct cache_dev_extent cache;
> +     int state;
> +
> +     u64 objectid;
> +     u8  type;
> +     u64 offset;
> +
> +     u64 chunk_objecteid;
> +     u64 chunk_offset;
> +     u64 length;
> +};
>  
>  static u64 bytes_used = 0;
>  static u64 total_csum_bytes = 0;
> @@ -1852,7 +1912,7 @@ static int all_backpointers_checked(struct 
> extent_record *rec, int print_errs)
>                                       (unsigned long long)rec->start,
>                                       back->full_backref ?
>                                       "parent" : "root",
> -                                     back->full_backref ? 
> +                                     back->full_backref ?
>                                       (unsigned long long)dback->parent:
>                                       (unsigned long long)dback->root,
>                                       (unsigned long long)dback->owner,
> @@ -2440,6 +2500,153 @@ static int process_extent_ref_v0(struct cache_tree 
> *extent_cache,
>  }
>  #endif
>  
> +static int process_chunk_item(struct cache_tree *chunk_cache,
> +             struct btrfs_key *key, struct extent_buffer *eb, int slot)
> +{
> +     struct btrfs_chunk *ptr;
> +     struct chunk_record *rec;
> +     int num_stripes, i;
> +     int ret = 0;
> +
> +     ptr = btrfs_item_ptr(eb,
> +             slot, struct btrfs_chunk);
> +
> +     num_stripes = btrfs_chunk_num_stripes(eb, ptr);
> +
> +     rec = malloc(sizeof(*rec) +
> +             num_stripes * sizeof(*rec->stripes));
> +     if (!rec) {
> +             fprintf(stderr, "memory allocation failed\n");
> +             return -ENOMEM;
> +     }
> +
> +     rec->cache.start = key->offset;
> +     rec->cache.size = 1;
> +     rec->state = REC_UNCHECKED;
> +
> +     rec->objectid = key->objectid;
> +     rec->type = key->type;
> +     rec->offset = key->offset;
> +
> +     rec->length = btrfs_chunk_length(eb, ptr);
> +     rec->type = btrfs_chunk_type(eb, ptr);
> +     rec->num_stripes = num_stripes;
> +
> +     for (i = 0; i < rec->num_stripes; ++i) {
> +             rec->stripes[i].devid =
> +                     btrfs_stripe_devid_nr(eb, ptr, i);
> +             rec->stripes[i].offset =
> +                     btrfs_stripe_offset_nr(eb, ptr, i);
> +     }
> +
> +     ret = insert_existing_cache_extent(
> +             chunk_cache, &rec->cache);
> +
> +     return ret;
> +}
> +
> +static int process_dev_item(struct cache_tree *dev_cache,
> +             struct btrfs_key *key, struct extent_buffer *eb, int slot)
> +{
> +     struct btrfs_dev_item *ptr;
> +     struct dev_record *rec;
> +     int ret = 0;
> +
> +     ptr = btrfs_item_ptr(eb,
> +             slot, struct btrfs_dev_item);
> +
> +     rec = malloc(sizeof(*rec));
> +     if (!rec) {
> +             fprintf(stderr, "memory allocation failed\n");
> +             return -ENOMEM;
> +     }
> +
> +     rec->cache.start = key->offset;
> +     rec->cache.size = 1;
> +     rec->state = REC_UNCHECKED;
> +
> +     rec->objectid = key->objectid;
> +     rec->type = key->type;
> +     rec->offset = key->offset;
> +
> +     rec->devid = btrfs_device_id(eb, ptr);
> +     rec->total_byte = btrfs_device_total_bytes(eb, ptr);
> +     rec->byte_used = btrfs_device_bytes_used(eb, ptr);
> +
> +     ret = insert_existing_cache_extent(
> +             dev_cache, &rec->cache);
> +
> +     return ret;
> +}
> +
> +static int process_block_group_item(struct cache_tree *block_group_cache,
> +             struct btrfs_key *key, struct extent_buffer *eb, int slot)
> +{
> +     struct btrfs_block_group_item *ptr;
> +     struct block_group_record *rec;
> +     int ret = 0;
> +
> +     ptr = btrfs_item_ptr(eb, slot,
> +             struct btrfs_block_group_item);
> +
> +     rec = malloc(sizeof(*rec));
> +     if (!rec) {
> +             fprintf(stderr, "memory allocation failed\n");
> +             return -ENOMEM;
> +     }
> +
> +     rec->cache.start = key->objectid;
> +     rec->cache.size = 1;
> +     rec->state = REC_UNCHECKED;
> +
> +     rec->objectid = key->objectid;
> +     rec->type = key->type;
> +     rec->offset = key->offset;
> +     rec->flags = btrfs_disk_block_group_flags(eb, ptr);
> +
> +     ret = insert_existing_cache_extent(
> +             block_group_cache, &rec->cache);
> +
> +     return ret;
> +}
> +
> +static int process_dev_extent_item(struct dev_extent_tree *dev_extent_cache,
> +             struct btrfs_key *key, struct extent_buffer *eb, int slot)
> +{
> +     int ret = 0;
> +
> +     struct btrfs_dev_extent *ptr;
> +     struct dev_extent_record *rec;
> +
> +     ptr = btrfs_item_ptr(eb,
> +             slot, struct btrfs_dev_extent);
> +
> +     rec = malloc(sizeof(*rec));
> +     if (!rec) {
> +             fprintf(stderr, "memory allocation failed\n");
> +             return -ENOMEM;
> +     }
> +
> +     rec->cache.devno = key->objectid;
> +     rec->cache.offset = key->offset;
> +     rec->state = REC_UNCHECKED;
> +
> +     rec->objectid = key->objectid;
> +     rec->type = key->type;
> +     rec->offset = key->offset;
> +
> +     rec->chunk_objecteid =
> +             btrfs_dev_extent_chunk_objectid(eb, ptr);
> +     rec->chunk_offset =
> +             btrfs_dev_extent_chunk_offset(eb, ptr);
> +     rec->length = btrfs_dev_extent_length(eb, ptr);
> +
> +     ret = insert_existing_cache_dev_extent(
> +             dev_extent_cache, &rec->cache);
> +
> +     return ret;
> +}
> +
>  static int process_extent_item(struct cache_tree *extent_cache,
>                              struct extent_buffer *eb, int slot)
>  {
> @@ -2531,7 +2738,11 @@ static int run_next_block(struct btrfs_root *root,
>                         struct cache_tree *seen,
>                         struct cache_tree *reada,
>                         struct cache_tree *nodes,
> -                       struct cache_tree *extent_cache)
> +                       struct cache_tree *extent_cache,
> +                       struct cache_tree *chunk_cache,
> +                       struct cache_tree *dev_cache,
> +                       struct cache_tree *block_group_cache,
> +                       struct dev_extent_tree *dev_extent_cache)
>  {
>       struct extent_buffer *buf;
>       u64 bytenr;
> @@ -2622,8 +2833,24 @@ static int run_next_block(struct btrfs_root *root,
>                                       btrfs_item_size_nr(buf, i);
>                               continue;
>                       }
> +                     if (key.type == BTRFS_CHUNK_ITEM_KEY) {
> +                             process_chunk_item(chunk_cache, &key, buf, i);
> +                             continue;
> +                     }
> +                     if (key.type == BTRFS_DEV_ITEM_KEY) {
> +                             process_dev_item(dev_cache, &key, buf, i);
> +                             continue;
> +                     }
>                       if (key.type == BTRFS_BLOCK_GROUP_ITEM_KEY) {
> +                             process_block_group_item(block_group_cache,
> +                                     &key, buf, i);
> +                             continue;
> +                     }
> +                     if (key.type == BTRFS_DEV_EXTENT_KEY) {
> +                             process_dev_extent_item(dev_extent_cache,
> +                                     &key, buf, i);
>                               continue;
> +
>                       }
>                       if (key.type == BTRFS_EXTENT_REF_V0_KEY) {
>  #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
> @@ -2663,7 +2890,7 @@ static int run_next_block(struct btrfs_root *root,
>                               ref = btrfs_item_ptr(buf, i,
>                                               struct btrfs_shared_data_ref);
>                               add_data_backref(extent_cache,
> -                                     key.objectid, key.offset, 0, 0, 0, 
> +                                     key.objectid, key.offset, 0, 0, 0,
>                                       btrfs_shared_data_ref_count(buf, ref),
>                                       0, root->sectorsize);
>                               continue;
> @@ -3366,9 +3593,260 @@ repair_abort:
>       return err;
>  }
>  
> +static void free_chunk_cache(struct cache_tree *chunk_cache)
> +{
> +     struct cache_extent *cache;
> +     while (1) {
> +             struct chunk_record *rec;
> +
> +             cache = find_first_cache_extent(chunk_cache, 0);
> +             if (!cache)
> +                     break;
> +             rec = container_of(cache, struct chunk_record, cache);
> +             if (rec->state == REC_UNCHECKED) {
> +                     fprintf(stderr,
> +                             "Chunk[%llu, %u, %llu] "
> +                             "is not referred by any others\n",
> +                             rec->objectid,
> +                             rec->type,
> +                             rec->offset);
> +             }
> +
> +             remove_cache_extent(chunk_cache, &rec->cache);
> +             free(rec);
> +     }
> +}
> +
> +static void free_dev_cache(struct cache_tree *dev_cache)
> +{
> +     struct cache_extent *cache;
> +     while (1) {
> +             struct dev_record *rec;
> +
> +             cache = find_first_cache_extent(dev_cache, 0);
> +             if (!cache)
> +                     break;
> +             rec = container_of(cache, struct dev_record, cache);
> +             if (rec->state == REC_UNCHECKED) {
> +                     fprintf(stderr,
> +                             "Dev[%llu, %u, %llu] "
> +                             "is not referred by any others\n",
> +                             rec->objectid,
> +                             rec->type,
> +                             rec->offset);
> +             }
> +
> +             remove_cache_extent(dev_cache, &rec->cache);
> +             free(rec);
> +     }
> +}
> +
> +static void free_block_group_cache(struct cache_tree *block_group_cache)
> +{
> +     struct cache_extent *cache;
> +     while (1) {
> +             struct block_group_record *rec;
> +
> +             cache = find_first_cache_extent(block_group_cache, 0);
> +             if (!cache)
> +                     break;
> +             rec = container_of(cache, struct block_group_record, cache);
> +             if (rec->state == REC_UNCHECKED) {
> +                     fprintf(stderr,
> +                             "Block group[%llu, %u, %llu] "
> +                             "is not referred by any others\n",
> +                             rec->objectid,
> +                             rec->type,
> +                             rec->offset);
> +             }
> +
> +             remove_cache_extent(block_group_cache, &rec->cache);
> +             free(rec);
> +     }
> +}
> +
> +static void free_dev_extent_cache(struct dev_extent_tree *dev_extent_cache)
> +{
> +     struct cache_dev_extent *cache;
> +     while (1) {
> +             struct dev_extent_record *rec;
> +
> +             cache = find_first_cache_dev_extent(dev_extent_cache, 0);
> +             if (!cache)
> +                     break;
> +             rec = container_of(cache, struct dev_extent_record, cache);
> +             if (rec->state == REC_UNCHECKED) {
> +                     fprintf(stderr,
> +                             "Dev extent[%llu, %u, %llu] "
> +                             "is not referred by any others\n",
> +                             rec->objectid,
> +                             rec->type,
> +                             rec->offset);
> +             }
> +
> +             remove_cache_dev_extent(dev_extent_cache, &rec->cache);
> +             free(rec);
> +     }
> +}
> +
> +/* check btrfs_chunk -> btrfs_dev_extent / btrfs_block_group_item */
> +static int check_chunk_refs(struct cache_tree *chunk_cache,
> +                             struct cache_tree *block_group_cache,
> +                             struct dev_extent_tree *dev_extent_cache)
> +{
> +     struct cache_extent *chunk_item;
> +     struct chunk_record *chunk_rec;
> +     int err = 0;
> +
> +     chunk_item = find_first_cache_extent(chunk_cache, 0);
> +     while (chunk_item) {
> +             struct cache_extent *block_group_item;
> +             struct block_group_record *block_group_rec;
> +
> +             struct cache_dev_extent *dev_extent_item;
> +             struct dev_extent_record *dev_extent_rec;
> +             int i;
> +
> +             chunk_rec = container_of(
> +                     chunk_item, struct chunk_record, cache);
> +
> +             block_group_item = find_cache_extent(block_group_cache,
> +                     chunk_rec->offset, 1);
> +             if (block_group_item) {
> +                     block_group_rec = container_of(block_group_item,
> +                             struct block_group_record, cache);
> +
> +                     if (chunk_rec->length != block_group_rec->offset)
> +                             err = -2;
> +                     if (chunk_rec->offset != block_group_rec->objectid)
> +                             err = -2;
> +                     if (chunk_rec->type != block_group_rec->flags)
> +                             err = -2;
> +
> +                     if (err != 0) {
> +                             BUG_ON(1);
> +                             fprintf(stderr,
> +                                     "Chunk[%llu, %u, %llu]: "
> +                                     "length(%llu), offset(%llu), type(%llu) 
> "
> +                                     "mismatch with block group[%llu, %u, 
> %llu]: "
> +                                     "offset(%llu), objectid(%llu), 
> flags(%llu)\n",
> +                                     chunk_rec->objectid,
> +                                     chunk_rec->type,
> +                                     chunk_rec->offset,
> +                                     chunk_rec->length,
> +                                     chunk_rec->offset,
> +                                     chunk_rec->type_flags,
> +                                     block_group_rec->objectid,
> +                                     block_group_rec->type,
> +                                     block_group_rec->offset,
> +                                     block_group_rec->offset,
> +                                     block_group_rec->objectid,
> +                                     block_group_rec->flags);
> +                     }
> +
> +                     block_group_rec->state = REC_CHECKED;
> +                     chunk_rec->state = REC_CHECKED;
> +             } else {
> +                     fprintf(stderr,
> +                             "Chunk[%llu, %u, %llu]: "
> +                             "length(%llu), offset(%llu), type(%llu) "
> +                             "is not found in block group\n",
> +                             chunk_rec->objectid,
> +                             chunk_rec->type,
> +                             chunk_rec->offset,
> +                             chunk_rec->length,
> +                             chunk_rec->offset,
> +                             chunk_rec->type_flags);
> +                     err = -1;
> +             }
> +
> +             for (i = 0; i < chunk_rec->num_stripes; ++i) {
> +                     dev_extent_item = find_cache_dev_extent(
> +                             dev_extent_cache,
> +                             chunk_rec->stripes[i].devid,
> +                             chunk_rec->stripes[i].offset);
> +                     if (dev_extent_item) {
> +                             dev_extent_rec = container_of(dev_extent_item,
> +                                     struct dev_extent_record, cache);
> +                             dev_extent_rec->state = REC_CHECKED;
> +                             chunk_rec->state = REC_CHECKED;
> +                     } else {
> +                             fprintf(stderr,
> +                                     "Chunk[%llu, %u, %llu] stripe[%llu, 
> %llu]"
> +                                     "is not found in dev extent\n",
> +                                     chunk_rec->objectid,
> +                                     chunk_rec->type,
> +                                     chunk_rec->offset,
> +                                     chunk_rec->stripes[i].devid,
> +                                     chunk_rec->stripes[i].offset);
> +                             err = -1;
> +                     }
> +             }
> +
> +             chunk_item = next_cache_extent(chunk_item);
> +     }
> +     return err;
> +}
> +
> +/* check btrfs_dev_item -> btrfs_dev_extent */
> +static int check_dev_refs(struct cache_tree *dev_cache,
> +                     struct dev_extent_tree *dev_extent_cache)
> +{
> +     struct cache_extent *dev_item;
> +     struct dev_record *dev_rec;
> +     int err = 0;
> +
> +     dev_item = find_first_cache_extent(dev_cache, 0);
> +     while (dev_item) {
> +             struct cache_dev_extent *dev_extent_item;
> +             struct dev_extent_record *dev_extent_rec;
> +             u64 total_byte = 0;
> +
> +             dev_rec = container_of(dev_item, struct dev_record, cache);
> +
> +             dev_extent_item = find_first_cache_dev_extent(
> +                     dev_extent_cache, 0);
> +             while (dev_extent_item) {
> +                     dev_extent_rec = container_of(dev_extent_item,
> +                             struct dev_extent_record, cache);
> +
> +                     if (dev_extent_rec->objectid == dev_rec->devid)
> +                             total_byte += dev_extent_rec->length;
> +
> +                     dev_extent_item = next_cache_dev_extent(
> +                             dev_extent_item);
> +             }
> +
> +             if (total_byte != dev_rec->byte_used) {
> +                     err = -2;
> +
> +                     BUG_ON(1);
> +                     fprintf(stderr,
> +                             "Dev extent's total-byte(%llu)"
> +                             "is not equal to byte-used(%llu) in"
> +                             "dev[%llu, %u, %llu]\n",
> +                             total_byte,
> +                             dev_rec->byte_used,
> +                             dev_rec->objectid,
> +                             dev_rec->type,
> +                             dev_rec->offset);
> +             }
> +
> +             dev_rec->state = REC_CHECKED;
> +
> +             dev_item = next_cache_extent(dev_item);
> +     }
> +     return err;
> +}
> +
>  static int check_extents(struct btrfs_trans_handle *trans,
>                        struct btrfs_root *root, int repair)
>  {
> +     struct cache_tree dev_cache;
> +     struct cache_tree chunk_cache;
> +     struct cache_tree block_group_cache;
> +     struct dev_extent_tree dev_extent_cache;
> +
>       struct cache_tree extent_cache;
>       struct cache_tree seen;
>       struct cache_tree pending;
> @@ -3378,7 +3856,7 @@ static int check_extents(struct btrfs_trans_handle 
> *trans,
>       struct btrfs_path path;
>       struct btrfs_key key;
>       struct btrfs_key found_key;
> -     int ret;
> +     int ret, err = 0;
>       u64 last = 0;
>       struct block_info *bits;
>       int bits_nr;
> @@ -3386,6 +3864,11 @@ static int check_extents(struct btrfs_trans_handle 
> *trans,
>       int slot;
>       struct btrfs_root_item ri;
>  
> +     cache_tree_init(&dev_cache);
> +     cache_tree_init(&chunk_cache);
> +     cache_tree_init(&block_group_cache);
> +     dev_extent_tree_init(&dev_extent_cache);
> +
>       cache_tree_init(&extent_cache);
>       cache_tree_init(&seen);
>       cache_tree_init(&pending);
> @@ -3452,11 +3935,28 @@ static int check_extents(struct btrfs_trans_handle 
> *trans,
>       btrfs_release_path(root, &path);
>       while(1) {
>               ret = run_next_block(root, bits, bits_nr, &last, &pending,
> -                                  &seen, &reada, &nodes, &extent_cache);
> +                                  &seen, &reada, &nodes, &extent_cache,
> +                                  &chunk_cache, &dev_cache,
> +                                  &block_group_cache, &dev_extent_cache);
>               if (ret != 0)
>                       break;
>       }
>       ret = check_extent_refs(trans, root, &extent_cache, repair);
> +     if (ret) {
> +             err = 1;
> +             fprintf(stderr, "Errors found in extent checking\n");
> +     }
> +     ret = check_chunk_refs(&chunk_cache,
> +             &block_group_cache, &dev_extent_cache);
> +     if (ret) {
> +             err = 1;
> +             fprintf(stderr, "Errors found in chunk refs checking\n");
> +     }
> +     ret = check_dev_refs(&dev_cache, &dev_extent_cache);
> +     if (ret) {
> +             err = 1;
> +             fprintf(stderr, "Errors found in dev refs checking\n");
> +     }
>  
>       if (repair) {
>               free_corrupt_blocks(root->fs_info);
> @@ -3465,7 +3965,12 @@ static int check_extents(struct btrfs_trans_handle 
> *trans,
>               root->fs_info->corrupt_blocks = NULL;
>       }
>  
> -     return ret;
> +     free_chunk_cache(&chunk_cache);
> +     free_dev_cache(&dev_cache);
> +     free_block_group_cache(&block_group_cache);
> +     free_dev_extent_cache(&dev_extent_cache);
> +
> +     return err;
>  }
>  
>  static void print_usage(void)
> diff --git a/dev-extent-cache.c b/dev-extent-cache.c
> new file mode 100644
> index 0000000..1f0d047
> --- /dev/null
> +++ b/dev-extent-cache.c
> @@ -0,0 +1,188 @@
> +/*
> + * Copyright (C) 2012 Fujitsu.  All rights reserved.
> + *
> + * This program is free software; you can redistribute it and/or
> + * modify it under the terms of the GNU General Public
> + * License v2 as published by the Free Software Foundation.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
> + * General Public License for more details.
> + *
> + * You should have received a copy of the GNU General Public
> + * License along with this program; if not, write to the
> + * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
> + * Boston, MA 021110-1307, USA.
> + */
> +#include <stdio.h>
> +#include <stdlib.h>
> +#include "kerncompat.h"
> +#include "dev-extent-cache.h"
> +
> +void dev_extent_tree_init(struct dev_extent_tree *tree)
> +{
> +     tree->root.rb_node = NULL;
> +}
> +
> +static struct rb_node *tree_insert(struct rb_root *root, u64 devno,
> +                                u64 offset, struct rb_node *node)
> +{
> +     struct rb_node **p = &root->rb_node;
> +     struct rb_node *parent = NULL;
> +     struct cache_dev_extent *entry;
> +
> +     while (*p) {
> +             parent = *p;
> +             entry = rb_entry(parent, struct cache_dev_extent, rb_node);
> +
> +             if (devno == entry->devno) {
> +                     if (offset < entry->offset)
> +                             p = &(*p)->rb_left;
> +                     else if (offset > entry->offset)
> +                             p = &(*p)->rb_right;
> +                     else
> +                             return parent;
> +             } else {
> +                     if (devno < entry->devno)
> +                             p = &(*p)->rb_left;
> +                     else if (devno > entry->devno)
> +                             p = &(*p)->rb_right;
> +                     else
> +                             return parent;
> +             }
> +     }
> +
> +     entry = rb_entry(parent, struct cache_dev_extent, rb_node);
> +     rb_link_node(node, parent, p);
> +     rb_insert_color(node, root);
> +     return NULL;
> +}
> +
> +static struct rb_node *__tree_search(struct rb_root *root, u64 devno,
> +                                  u64 offset, struct rb_node **prev_ret)
> +{
> +     struct rb_node *n = root->rb_node;
> +     struct rb_node *prev = NULL;
> +     struct cache_dev_extent *entry;
> +     struct cache_dev_extent *prev_entry = NULL;
> +
> +     while (n) {
> +             entry = rb_entry(n, struct cache_dev_extent, rb_node);
> +             prev = n;
> +             prev_entry = entry;
> +
> +             if (devno == entry->devno) {
> +                     if (offset < entry->offset)
> +                             n = n->rb_left;
> +                     else if (offset > entry->offset)
> +                             n = n->rb_right;
> +                     else
> +                             return n;
> +             } else {
> +                     if (devno < entry->devno)
> +                             n = n->rb_left;
> +                     else if (devno > entry->devno)
> +                             n = n->rb_right;
> +                     else
> +                             return n;
> +             }
> +     }
> +     if (!prev_ret)
> +             return NULL;
> +
> +     while (prev && devno >= prev_entry->devno + prev_entry->offset) {
> +             prev = rb_next(prev);
> +             prev_entry = rb_entry(prev, struct cache_dev_extent, rb_node);
> +     }
> +     *prev_ret = prev;
> +     return NULL;
> +}
> +
> +struct cache_dev_extent *alloc_cache_dev_extent(u64 devno, u64 offset)
> +{
> +     struct cache_dev_extent *pe = malloc(sizeof(*pe));
> +
> +     if (!pe)
> +             return pe;
> +     pe->devno = devno;
> +     pe->offset = offset;
> +     return pe;
> +}
> +
> +int insert_existing_cache_dev_extent(struct dev_extent_tree *tree,
> +                              struct cache_dev_extent *pe)
> +{
> +     struct rb_node *found;
> +
> +     found = tree_insert(&tree->root, pe->devno, pe->offset, &pe->rb_node);
> +     if (found)
> +             return -EEXIST;
> +
> +     return 0;
> +}
> +
> +int insert_cache_dev_extent(struct dev_extent_tree *tree, u64 devno, u64 
> offset)
> +{
> +     struct cache_dev_extent *pe = alloc_cache_dev_extent(devno, offset);
> +     int ret;
> +     ret = insert_existing_cache_dev_extent(tree, pe);
> +     if (ret)
> +             free(pe);
> +     return ret;
> +}
> +
> +struct cache_dev_extent *find_cache_dev_extent(struct dev_extent_tree *tree,
> +                                        u64 devno, u64 offset)
> +{
> +     struct rb_node *prev;
> +     struct rb_node *ret;
> +     struct cache_dev_extent *entry;
> +     ret = __tree_search(&tree->root, devno, offset, &prev);
> +     if (!ret)
> +             return NULL;
> +
> +     entry = rb_entry(ret, struct cache_dev_extent, rb_node);
> +     return entry;
> +}
> +
> +struct cache_dev_extent *find_first_cache_dev_extent(
> +                             struct dev_extent_tree *tree, u64 devno)
> +{
> +     struct rb_node *prev;
> +     struct rb_node *ret;
> +     struct cache_dev_extent *entry;
> +
> +     ret = __tree_search(&tree->root, devno, 1, &prev);
> +     if (!ret)
> +             ret = prev;
> +     if (!ret)
> +             return NULL;
> +     entry = rb_entry(ret, struct cache_dev_extent, rb_node);
> +     return entry;
> +}
> +
> +struct cache_dev_extent *prev_cache_dev_extent(struct cache_dev_extent *pe)
> +{
> +     struct rb_node *node = rb_prev(&pe->rb_node);
> +
> +     if (!node)
> +             return NULL;
> +     return rb_entry(node, struct cache_dev_extent, rb_node);
> +}
> +
> +struct cache_dev_extent *next_cache_dev_extent(struct cache_dev_extent *pe)
> +{
> +     struct rb_node *node = rb_next(&pe->rb_node);
> +
> +     if (!node)
> +             return NULL;
> +     return rb_entry(node, struct cache_dev_extent, rb_node);
> +}
> +
> +void remove_cache_dev_extent(struct dev_extent_tree *tree,
> +                              struct cache_dev_extent *pe)
> +{
> +     rb_erase(&pe->rb_node, &tree->root);
> +}
> +
> diff --git a/dev-extent-cache.h b/dev-extent-cache.h
> new file mode 100644
> index 0000000..9be2e2f
> --- /dev/null
> +++ b/dev-extent-cache.h
> @@ -0,0 +1,60 @@
> +/*
> + * Copyright (C) 2012 Fujitsu.  All rights reserved.
> + *
> + * This program is free software; you can redistribute it and/or
> + * modify it under the terms of the GNU General Public
> + * License v2 as published by the Free Software Foundation.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
> + * General Public License for more details.
> + *
> + * You should have received a copy of the GNU General Public
> + * License along with this program; if not, write to the
> + * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
> + * Boston, MA 021110-1307, USA.
> + */
> +
> +#ifndef __PENDING_DEV_EXTENT__
> +#define __PENDING_DEV_EXTENT__
> +#include "kerncompat.h"
> +#include "rbtree.h"
> +
> +struct dev_extent_tree {
> +     struct rb_root root;
> +};
> +
> +struct cache_dev_extent {
> +     struct rb_node rb_node;
> +     u64 devno;
> +     u64 offset;
> +};
> +
> +void dev_extent_tree_init(struct dev_extent_tree *tree);
> +void remove_cache_dev_extent(struct dev_extent_tree *tree,
> +                       struct cache_dev_extent *pe);
> +struct cache_dev_extent *find_first_cache_dev_extent(
> +                             struct dev_extent_tree *tree, u64 devno);
> +struct cache_dev_extent *prev_cache_dev_extent(struct cache_dev_extent *pe);
> +struct cache_dev_extent *next_cache_dev_extent(struct cache_dev_extent *pe);
> +struct cache_dev_extent *find_cache_dev_extent(struct dev_extent_tree *tree,
> +                                        u64 devno, u64 offset);
> +int insert_cache_dev_extent(struct dev_extent_tree *tree,
> +                             u64 devno, u64 offset);
> +int insert_existing_cache_dev_extent(struct dev_extent_tree *tree,
> +                             struct cache_dev_extent *pe);
> +
> +static inline int dev_extent_tree_empty(struct dev_extent_tree *tree)
> +{
> +     return RB_EMPTY_ROOT(&tree->root);
> +}
> +
> +static inline void free_cache_dev_extent(struct cache_dev_extent *pe)
> +{
> +     free(pe);
> +}
> +
> +struct cache_dev_extent *alloc_pending_dev_extent(u64 devno, u64 offset);
> +
> +#endif
> 

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