On 2019/5/30 下午8:02, David Sterba wrote: > On Fri, May 03, 2019 at 08:30:54AM +0800, Qu Wenruo wrote: >> Under certain condition, we could have strange file extent item in log >> tree like: >> >> item 18 key (69599 108 397312) itemoff 15208 itemsize 53 >> extent data disk bytenr 0 nr 0 >> extent data offset 0 nr 18446744073709547520 ram 18446744073709547520 >> >> The num_bytes and ram_bytes part overflow. >> >> For num_bytes part, we can detect such overflow along with file offset >> (key->offset), as file_offset + num_bytes should never go beyond u64 >> max. >> >> For ram_bytes part, it's about the decompressed size of the extent, not >> directly related to the size. >> In theory is OK to have super large value, and put extra >> limitation on ram bytes may cause unexpected false alert. >> >> So in tree-checker, we only check if the file offset and num bytes >> overflow. >> >> Signed-off-by: Qu Wenruo <[email protected]> >> --- >> fs/btrfs/tree-checker.c | 9 +++++++++ >> 1 file changed, 9 insertions(+) >> >> diff --git a/fs/btrfs/tree-checker.c b/fs/btrfs/tree-checker.c >> index 4f4f5af6345a..795eb6c18456 100644 >> --- a/fs/btrfs/tree-checker.c >> +++ b/fs/btrfs/tree-checker.c >> @@ -112,6 +112,7 @@ static int check_extent_data_item(struct extent_buffer >> *leaf, >> struct btrfs_file_extent_item *fi; >> u32 sectorsize = fs_info->sectorsize; >> u32 item_size = btrfs_item_size_nr(leaf, slot); >> + u64 extent_end; >> >> if (!IS_ALIGNED(key->offset, sectorsize)) { >> file_extent_err(leaf, slot, >> @@ -186,6 +187,14 @@ static int check_extent_data_item(struct extent_buffer >> *leaf, >> CHECK_FE_ALIGNED(leaf, slot, fi, offset, sectorsize) || >> CHECK_FE_ALIGNED(leaf, slot, fi, num_bytes, sectorsize)) >> return -EUCLEAN; >> + /* Catch extent end overflow case */ >> + if (check_add_overflow(btrfs_file_extent_num_bytes(leaf, fi), >> + key->offset, &extent_end)) { >> + file_extent_err(leaf, slot, >> + "extent end overflow, have file offset %llu extent num bytes %llu", >> + key->offset, >> + btrfs_file_extent_num_bytes(leaf, fi)); > > Isn't this missing > > return -EUCLEAN;
Oh, my bad. Would you mind to fold that return line? Thanks, Qu > > ? > >> + } >> return 0; >> } >> >> -- >> 2.21.0
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