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btrfs: Remove redundant WARN_ON in walk_down_log_tree

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level <0 and level >= BTRFS_MAX_LEVEL are already performed upon
extent buffer read by tree checker in btrfs_check_node.
go. As far as 'level <= 0'  we are guaranteed that level is '> 0'
because the value of level _before_ reading 'next' is larger than 1
(otherwise we wouldn't have executed that code at all) this in turn
guarantees that 'level' after btrfs_read_buffer is 'level - 1' since
we verify this invariant in:

    btrfs_read_buffer
     btree_read_extent_buffer_pages
      btrfs_verify_level_key

This guarantees that level can never be '<= 0' so the warn on is
never triggered.

Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This commit is contained in:
Nikolay Borisov 2019-12-02 11:40:14 +02:00 • committed by David Sterba
commit 36ee0b44ad
1 changed files with 0 additions and 9 deletions
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9
fs/btrfs/tree-log.c
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@ -2674,14 +2674,9 @@ static noinline int walk_down_log_tree(struct btrfs_trans_handle *trans,
u32 blocksize;
int ret = 0;
WARN_ON(*level < 0);
WARN_ON(*level >= BTRFS_MAX_LEVEL);
while (*level > 0) {
struct btrfs_key first_key;
WARN_ON(*level < 0);
WARN_ON(*level >= BTRFS_MAX_LEVEL);
cur = path->nodes[*level];
WARN_ON(btrfs_header_level(cur) != *level);
@ -2748,7 +2743,6 @@ static noinline int walk_down_log_tree(struct btrfs_trans_handle *trans,
return ret;
}
WARN_ON(*level <= 0);
if (path->nodes[*level-1])
free_extent_buffer(path->nodes[*level-1]);
path->nodes[*level-1] = next;
@ -2756,9 +2750,6 @@ static noinline int walk_down_log_tree(struct btrfs_trans_handle *trans,
path->slots[*level] = 0;
cond_resched();
}
WARN_ON(*level < 0);
WARN_ON(*level >= BTRFS_MAX_LEVEL);
path->slots[*level] = btrfs_header_nritems(path->nodes[*level]);
cond_resched();