On 5/16/12 3:50 AM, Tao Ma wrote: > From: Tao Ma <boyu.mt@xxxxxxxxxx> > > Now we can use fallocate to create a large file while keep the size > to be small. It will cause the e2fsck complain about it. The test > script is simple and I have pasted it here. > > DEVICE=/dev/sdb1 > mount -t ext4 $DEVICE /mnt/ext4 > for((i=0;i<10;i++))do fallocate -n -o $[$i*8192] -l 4096 /mnt/ext4/a;done > umount $DEVICE > e2fsck -fn $DEVICE Should this be put into an e2fsprogs regression test? > The error message will be like this: > e2fsck 1.42.3 (14-May-2012) > Pass 1: Checking inodes, blocks, and sizes > Inode 12 has zero length extent > (invalid logical block 0, physical block 32775) > Clear? no > > Inode 12, i_blocks is 88, should be 0. Fix? no > > Pass 2: Checking directory structure > Pass 3: Checking directory connectivity > Pass 4: Checking reference counts > Pass 5: Checking group summary information > Block bitmap differences: -(8231--8232) -(32770--32778) > Fix? no > > Now actually the end_blk can be any value which is less than > u32, so make end_blk be the maximum value of u32. > > Cc: Theodore Ts'o <tytso@xxxxxxx> > Signed-off-by: Tao Ma <boyu.mt@xxxxxxxxxx> > --- > lib/ext2fs/extent.c | 4 +--- > 1 files changed, 1 insertions(+), 3 deletions(-) > > diff --git a/lib/ext2fs/extent.c b/lib/ext2fs/extent.c > index eb096d6..e2815c2 100644 > --- a/lib/ext2fs/extent.c > +++ b/lib/ext2fs/extent.c > @@ -253,9 +253,7 @@ extern errcode_t ext2fs_extent_open2(ext2_filsys fs, ext2_ino_t ino, > ext2fs_le16_to_cpu(eh->eh_entries); > handle->path[0].max_entries = ext2fs_le16_to_cpu(eh->eh_max); > handle->path[0].curr = 0; > - handle->path[0].end_blk = > - (EXT2_I_SIZE(handle->inode) + fs->blocksize - 1) >> > - EXT2_BLOCK_SIZE_BITS(fs->super); Hm, so this picked the actual last block of the file, whereas > + handle->path[0].end_blk = ((((unsigned long long) 1) << 32) - 1); this gives it an upper bound... why is that ok? It's been a long time since I looked at this code, but some explanation in the commit and in code comments would be helpful. If end_blk can be any value less than u32, what is its purpose? -Eric > handle->path[0].visit_num = 1; > handle->level = 0; > handle->magic = EXT2_ET_MAGIC_EXTENT_HANDLE; -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
