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btrfs: switch to on-stack csum buffer in csum_tree_block

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The maximum size of a checksum buffer is known, BTRFS_CSUM_SIZE, and we
don't have to allocate it dynamically. This code path is not used at all
as we have only the crc32c and use an on-stack buffer already.

Signed-off-by: David Sterba <dsterba@suse.com>
This commit is contained in:
David Sterba 2017-11-06 19:23:00 +01:00
parent 343e4fc1c6
commit 71a635516c
1 changed files with 3 additions and 13 deletions
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16
fs/btrfs/disk-io.c
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@ -285,7 +285,7 @@ static int csum_tree_block(struct btrfs_fs_info *fs_info,
int verify)
{
u16 csum_size = btrfs_super_csum_size(fs_info->super_copy);
char *result = NULL;
char result[BTRFS_CSUM_SIZE];
unsigned long len;
unsigned long cur_len;
unsigned long offset = BTRFS_CSUM_SIZE;
@ -294,7 +294,6 @@ static int csum_tree_block(struct btrfs_fs_info *fs_info,
unsigned long map_len;
int err;
u32 crc = ~(u32)0;
unsigned long inline_result;
len = buf->len - offset;
while (len > 0) {
@ -308,13 +307,7 @@ static int csum_tree_block(struct btrfs_fs_info *fs_info,
len -= cur_len;
offset += cur_len;
}
if (csum_size > sizeof(inline_result)) {
result = kzalloc(csum_size, GFP_NOFS);
if (!result)
return -ENOMEM;
} else {
result = (char *)&inline_result;
}
memset(result, 0, BTRFS_CSUM_SIZE);
btrfs_csum_final(crc, result);
@ -329,15 +322,12 @@ static int csum_tree_block(struct btrfs_fs_info *fs_info,
"%s checksum verify failed on %llu wanted %X found %X level %d",
fs_info->sb->s_id, buf->start,
val, found, btrfs_header_level(buf));
if (result != (char *)&inline_result)
kfree(result);
return -EUCLEAN;
}
} else {
write_extent_buffer(buf, result, 0, csum_size);
}
if (result != (char *)&inline_result)
kfree(result);
return 0;
}