From mboxrd@z Thu Jan 1 00:00:00 1970 From: chengwei.yang@intel.com (Yang Chengwei) Date: Wed, 8 Aug 2012 18:28:38 +0800 Subject: first block in ext3 filesystem In-Reply-To: References: Message-ID: <20120808102838.GC19096@chengwei-debian> To: kernelnewbies@lists.kernelnewbies.org List-Id: kernelnewbies.lists.kernelnewbies.org On Mon, Aug 06, 2012 at 11:19:57AM -0700, Manish Katiyar wrote: > > On Mon, Aug 6, 2012 at 11:04 AM, Prashant Shah wrote: > > Hi, > > I came across this > > $sudo dumpe2fs /dev/sda1 > > 4KB Block Size > Group 0: (Blocks 0-32767) > Primary superblock at 0, Group descriptors at 1-1 > > 1KB Block Size > Group 0: (Blocks 1-8192) > Primary superblock at 1, Group descriptors at 2-2 > > Why does first block start from 0 in the 4KB block size partition and > 1 in 1KB block size partition ? > > > Let's say superblock is always written at a fixed offset of 1024 (they have to As Shah said, the superblock is always written at a offset 1024. When the block size is 4096, offset 1024 is in the first block (block 0), while the block size is 1024, offset 1024 is in the second block (block 1). Since group descriptor locates after superblock, so Group 0 starts from 1 when the block size is 1024 byte. Please correct me if I'm wrong. -- Thanks, Chengwei > because e2fsck has to find it) in the filesystem. What would be the block > numbers with block sizes 1k and 4k ? > > > > > Regards. > > _______________________________________________ > Kernelnewbies mailing list > Kernelnewbies at kernelnewbies.org > http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies > > > > > -- > Thanks - > Manish > > _______________________________________________ > Kernelnewbies mailing list > Kernelnewbies at kernelnewbies.org > http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies -------------- next part -------------- A non-text attachment was scrubbed... Name: not available Type: application/pgp-signature Size: 490 bytes Desc: Digital signature Url : http://lists.kernelnewbies.org/pipermail/kernelnewbies/attachments/20120808/c3c39766/attachment.bin