On 8/12/13 6:21 PM, Eric Sandeen wrote:
> On 7/21/13 3:28 PM, Eric Whitney wrote:
>> Commit d3f32c2db8 caused e2fsck misbehavior during xfstests runs.
>> It reported that uninitialized extents created by fallocate() at
>> the end of file with the FALLOC_FL_KEEP_SIZE flag were invalid.
>> Because FALLOC_FL_KEEP_SIZE does not increase the file size when
>> an extent is fallocated, an uninitialized extent can legally contain
>> blocks past the end of file.
>>
>> The information reported by ext2fs_extent_get() and used by the commit
>> to determine legal extent ranges is limited by the value of i_size
>> (determines end_blk in the root extent index), so block values greater
>> than that containing i_size were reported as invalid.
>>
>> To fix this, filter out possible invalid extent candidates if they are
>> uninitialized and extend past the block containing the end of file.
>>
>> Signed-off-by: Eric Whitney <enwlinux@xxxxxxxxx>
>> ---
>> e2fsck/pass1.c | 4 +++-
>> lib/ext2fs/ext2fs.h | 1 +
>> lib/ext2fs/extent.c | 1 +
>> 3 files changed, 5 insertions(+), 1 deletion(-)
>>
>> diff --git a/e2fsck/pass1.c b/e2fsck/pass1.c
>> index ba6025b..b84b0d0 100644
>> --- a/e2fsck/pass1.c
>> +++ b/e2fsck/pass1.c
>> @@ -1892,7 +1892,9 @@ static void scan_extent_node(e2fsck_t ctx, struct problem_context *pctx,
>> problem = PR_1_EXTENT_BAD_START_BLK;
>> else if (extent.e_lblk < start_block)
>> problem = PR_1_OUT_OF_ORDER_EXTENTS;
>> - else if (end_block && last_lblk > end_block)
>> + else if ((end_block && last_lblk > end_block) &&
>> + (!(extent.e_flags & EXT2_EXTENT_FLAGS_UNINIT &&
>> + last_lblk > info.eof_blk - 1)))
>> problem = PR_1_EXTENT_END_OUT_OF_BOUNDS;
>> else if (is_leaf && extent.e_len == 0)
>> problem = PR_1_EXTENT_LENGTH_ZERO;
>> diff --git a/lib/ext2fs/ext2fs.h b/lib/ext2fs/ext2fs.h
>> index 311ceda..85f2ac8 100644
>> --- a/lib/ext2fs/ext2fs.h
>> +++ b/lib/ext2fs/ext2fs.h
>> @@ -409,6 +409,7 @@ struct ext2_extent_info {
>> int bytes_avail;
>> blk64_t max_lblk;
>> blk64_t max_pblk;
>> + blk64_t eof_blk;
>> __u32 max_len;
>> __u32 max_uninit_len;
>> };
>
> I just realized, this affects the ABI, doesn't it? Hm.
>
> As a hack-around, can probably just use ehandle->path[0].end_blk directly
> in scan_extent_node and stash eof_blk locally?
Nope, we can't crack an extent handle, it's an opaque type.
Ned some V2 interfaces now? :(
> -Eric
>
>> diff --git a/lib/ext2fs/extent.c b/lib/ext2fs/extent.c
>> index 65bb099..de54319 100644
>> --- a/lib/ext2fs/extent.c
>> +++ b/lib/ext2fs/extent.c
>> @@ -1572,6 +1572,7 @@ errcode_t ext2fs_extent_get_info(ext2_extent_handle_t handle,
>> info->max_depth = handle->max_depth;
>> info->max_lblk = ((__u64) 1 << 32) - 1;
>> info->max_pblk = ((__u64) 1 << 48) - 1;
>> + info->eof_blk = handle->path[0].end_blk;
>> info->max_len = (1UL << 15);
>> info->max_uninit_len = (1UL << 15) - 1;
>>
>>
>
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