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btrfs: Move and unexport btrfs_rmap_block
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It's used only during initial block group reading to map physical
address of super block to a list of logical ones. Make it private to
block-group.c, add proper kernel doc and ensure it's exported only for
tests.

Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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Nikolay Borisov authored and David Sterba committed Jan 23, 2020
1 parent 68c467c commit 96a1433
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Showing 4 changed files with 91 additions and 71 deletions.
86 changes: 86 additions & 0 deletions fs/btrfs/block-group.c
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Original file line number Diff line number Diff line change
Expand Up @@ -15,6 +15,7 @@
#include "tree-log.h"
#include "delalloc-space.h"
#include "discard.h"
#include "raid56.h"

/*
* Return target flags in extended format or 0 if restripe for this chunk_type
Expand Down Expand Up @@ -1561,6 +1562,91 @@ static void set_avail_alloc_bits(struct btrfs_fs_info *fs_info, u64 flags)
write_sequnlock(&fs_info->profiles_lock);
}

/**
* btrfs_rmap_block - Map a physical disk address to a list of logical addresses
* @chunk_start: logical address of block group
* @physical: physical address to map to logical addresses
* @logical: return array of logical addresses which map to @physical
* @naddrs: length of @logical
* @stripe_len: size of IO stripe for the given block group
*
* Maps a particular @physical disk address to a list of @logical addresses.
* Used primarily to exclude those portions of a block group that contain super
* block copies.
*/
EXPORT_FOR_TESTS
int btrfs_rmap_block(struct btrfs_fs_info *fs_info, u64 chunk_start,
u64 physical, u64 **logical, int *naddrs, int *stripe_len)
{
struct extent_map *em;
struct map_lookup *map;
u64 *buf;
u64 bytenr;
u64 length;
u64 stripe_nr;
u64 rmap_len;
int i, j, nr = 0;

em = btrfs_get_chunk_map(fs_info, chunk_start, 1);
if (IS_ERR(em))
return -EIO;

map = em->map_lookup;
length = em->len;
rmap_len = map->stripe_len;

if (map->type & BTRFS_BLOCK_GROUP_RAID10)
length = div_u64(length, map->num_stripes / map->sub_stripes);
else if (map->type & BTRFS_BLOCK_GROUP_RAID0)
length = div_u64(length, map->num_stripes);
else if (map->type & BTRFS_BLOCK_GROUP_RAID56_MASK) {
length = div_u64(length, nr_data_stripes(map));
rmap_len = map->stripe_len * nr_data_stripes(map);
}

buf = kcalloc(map->num_stripes, sizeof(u64), GFP_NOFS);
BUG_ON(!buf); /* -ENOMEM */

for (i = 0; i < map->num_stripes; i++) {
if (map->stripes[i].physical > physical ||
map->stripes[i].physical + length <= physical)
continue;

stripe_nr = physical - map->stripes[i].physical;
stripe_nr = div64_u64(stripe_nr, map->stripe_len);

if (map->type & BTRFS_BLOCK_GROUP_RAID10) {
stripe_nr = stripe_nr * map->num_stripes + i;
stripe_nr = div_u64(stripe_nr, map->sub_stripes);
} else if (map->type & BTRFS_BLOCK_GROUP_RAID0) {
stripe_nr = stripe_nr * map->num_stripes + i;
}
/*
* The remaining case would be for RAID56, multiply by
* nr_data_stripes(). Alternatively, just use rmap_len below
* instead of map->stripe_len
*/

bytenr = chunk_start + stripe_nr * rmap_len;
WARN_ON(nr >= map->num_stripes);
for (j = 0; j < nr; j++) {
if (buf[j] == bytenr)
break;
}
if (j == nr) {
WARN_ON(nr >= map->num_stripes);
buf[nr++] = bytenr;
}
}

*logical = buf;
*naddrs = nr;
*stripe_len = rmap_len;

free_extent_map(em);
return 0;
}

static int exclude_super_stripes(struct btrfs_block_group *cache)
{
struct btrfs_fs_info *fs_info = cache->fs_info;
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5 changes: 5 additions & 0 deletions fs/btrfs/block-group.h
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Original file line number Diff line number Diff line change
Expand Up @@ -283,4 +283,9 @@ static inline int btrfs_block_group_done(struct btrfs_block_group *cache)
cache->cached == BTRFS_CACHE_ERROR;
}

#ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
int btrfs_rmap_block(struct btrfs_fs_info *fs_info, u64 chunk_start,
u64 physical, u64 **logical, int *naddrs, int *stripe_len);
#endif

#endif /* BTRFS_BLOCK_GROUP_H */
69 changes: 0 additions & 69 deletions fs/btrfs/volumes.c
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Original file line number Diff line number Diff line change
Expand Up @@ -6114,75 +6114,6 @@ int btrfs_map_sblock(struct btrfs_fs_info *fs_info, enum btrfs_map_op op,
return __btrfs_map_block(fs_info, op, logical, length, bbio_ret, 0, 1);
}

int btrfs_rmap_block(struct btrfs_fs_info *fs_info, u64 chunk_start,
u64 physical, u64 **logical, int *naddrs, int *stripe_len)
{
struct extent_map *em;
struct map_lookup *map;
u64 *buf;
u64 bytenr;
u64 length;
u64 stripe_nr;
u64 rmap_len;
int i, j, nr = 0;

em = btrfs_get_chunk_map(fs_info, chunk_start, 1);
if (IS_ERR(em))
return -EIO;

map = em->map_lookup;
length = em->len;
rmap_len = map->stripe_len;

if (map->type & BTRFS_BLOCK_GROUP_RAID10)
length = div_u64(length, map->num_stripes / map->sub_stripes);
else if (map->type & BTRFS_BLOCK_GROUP_RAID0)
length = div_u64(length, map->num_stripes);
else if (map->type & BTRFS_BLOCK_GROUP_RAID56_MASK) {
length = div_u64(length, nr_data_stripes(map));
rmap_len = map->stripe_len * nr_data_stripes(map);
}

buf = kcalloc(map->num_stripes, sizeof(u64), GFP_NOFS);
BUG_ON(!buf); /* -ENOMEM */

for (i = 0; i < map->num_stripes; i++) {
if (map->stripes[i].physical > physical ||
map->stripes[i].physical + length <= physical)
continue;

stripe_nr = physical - map->stripes[i].physical;
stripe_nr = div64_u64(stripe_nr, map->stripe_len);

if (map->type & BTRFS_BLOCK_GROUP_RAID10) {
stripe_nr = stripe_nr * map->num_stripes + i;
stripe_nr = div_u64(stripe_nr, map->sub_stripes);
} else if (map->type & BTRFS_BLOCK_GROUP_RAID0) {
stripe_nr = stripe_nr * map->num_stripes + i;
} /* else if RAID[56], multiply by nr_data_stripes().
* Alternatively, just use rmap_len below instead of
* map->stripe_len */

bytenr = chunk_start + stripe_nr * rmap_len;
WARN_ON(nr >= map->num_stripes);
for (j = 0; j < nr; j++) {
if (buf[j] == bytenr)
break;
}
if (j == nr) {
WARN_ON(nr >= map->num_stripes);
buf[nr++] = bytenr;
}
}

*logical = buf;
*naddrs = nr;
*stripe_len = rmap_len;

free_extent_map(em);
return 0;
}

static inline void btrfs_end_bbio(struct btrfs_bio *bbio, struct bio *bio)
{
bio->bi_private = bbio->private;
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2 changes: 0 additions & 2 deletions fs/btrfs/volumes.h
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Original file line number Diff line number Diff line change
Expand Up @@ -415,8 +415,6 @@ int btrfs_map_sblock(struct btrfs_fs_info *fs_info, enum btrfs_map_op op,
struct btrfs_bio **bbio_ret);
int btrfs_get_io_geometry(struct btrfs_fs_info *fs_info, enum btrfs_map_op op,
u64 logical, u64 len, struct btrfs_io_geometry *io_geom);
int btrfs_rmap_block(struct btrfs_fs_info *fs_info, u64 chunk_start,
u64 physical, u64 **logical, int *naddrs, int *stripe_len);
int btrfs_read_sys_array(struct btrfs_fs_info *fs_info);
int btrfs_read_chunk_tree(struct btrfs_fs_info *fs_info);
int btrfs_alloc_chunk(struct btrfs_trans_handle *trans, u64 type);
Expand Down

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