On 2018年02月09日 16:09, Nikolay Borisov wrote: > > > On 9.02.2018 09:44, Qu Wenruo wrote: >> Strangely, we have level check in btrfs_print_tree() while we don't have >> the same check in read_node_slot(). >> >> That's to say, for the following corruption, btrfs_search_slot() or >> btrfs_next_leaf() can return invalid leaf: >> >> Parent eb: >> node XXXXXX level 1 >> ^^^^^^^ >> Child should be leaf (level 0) >> ... >> key (XXX XXX XXX) block YYYYYY >> >> Child eb: >> leaf YYYYYY level 1 >> ^^^^^^^ >> Something went wrong now >> >> And for the corrupted leaf returned, later caller can be screwed up >> easily. >> >> Although the root cause (powerloss, but still something wrong breaking >> metadata CoW of btrfs) is still unknown, at least enhance btrfs-progs to >> avoid SEGV. >> >> Reported-by: Ralph Gauges <ralphgau...@googlemail.com> >> Signed-off-by: Qu Wenruo <w...@suse.com> >> --- >> changlog: >> v2: >> Check if the extent buffer is up-to-date before checking its level to >> avoid possible NULL pointer access. >> --- >> ctree.c | 16 +++++++++++++++- >> 1 file changed, 15 insertions(+), 1 deletion(-) > > That was sent separately so I'd assume it was in the wrong dir ;)
Yep, my bad habit of putting all patches in project dir.
Thanks,
Qu
>
>>
>> diff --git a/ctree.c b/ctree.c
>> index 4fc33b14000a..430805e3043f 100644
>> --- a/ctree.c
>> +++ b/ctree.c
>> @@ -22,6 +22,7 @@
>> #include "repair.h"
>> #include "internal.h"
>> #include "sizes.h"
>> +#include "messages.h"
>>
>> static int split_node(struct btrfs_trans_handle *trans, struct btrfs_root
>> *root, struct btrfs_path *path, int level);
>> @@ -640,7 +641,9 @@ static int bin_search(struct extent_buffer *eb, struct
>> btrfs_key *key,
>> struct extent_buffer *read_node_slot(struct btrfs_fs_info *fs_info,
>> struct extent_buffer *parent, int slot)
>> {
>> + struct extent_buffer *ret;
>> int level = btrfs_header_level(parent);
>> +
>> if (slot < 0)
>> return NULL;
>> if (slot >= btrfs_header_nritems(parent))
>> @@ -649,8 +652,19 @@ struct extent_buffer *read_node_slot(struct
>> btrfs_fs_info *fs_info,
>> if (level == 0)
>> return NULL;
>>
>> - return read_tree_block(fs_info, btrfs_node_blockptr(parent, slot),
>> + ret = read_tree_block(fs_info, btrfs_node_blockptr(parent, slot),
>> btrfs_node_ptr_generation(parent, slot));
>> + if (!extent_buffer_uptodate(ret))
>> + return ERR_PTR(-EIO);
>> +
>> + if (btrfs_header_level(ret) != level - 1) {
>> + error("child eb corrupted: parent bytenr=%llu item=%d parent
>> level=%d child level=%d",
>> + btrfs_header_bytenr(parent), slot,
>> + btrfs_header_level(parent), btrfs_header_level(ret));
>> + free_extent_buffer(ret);
>> + return ERR_PTR(-EIO);
>> + }
>> + return ret;
>> }
>>
>> static int balance_level(struct btrfs_trans_handle *trans,
>>
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