Sorry, resent due to SMTP error:
anyone knows any way of enumerating all the low level information like
these for each file?
Best I can get is "debugfs":
So using "show_inode_infor xxxx":
Inode: 1146884 Type: regular Mode: 0767 Flags: 0x0
Generation: 4262211373
User: 0 Group: 0 Size: 4670783
File ACL: 0 Directory ACL: 0
Links: 1 Blockcount: 9152
Fragment: Address: 0 Number: 0 Size: 0
ctime: 0x46db7fb6 -- Mon Sep 3 11:29:58 2007
atime: 0x47c66735 -- Thu Feb 28 15:48:05 2008
mtime: 0x43118298 -- Sun Aug 28 17:23:36 2005
BLOCKS:
(0-11):2317946-0, (IND):2317958, (12-1035):2317959-0, (DIND):2318983,
(IND):2318984, (1036-1140):2318985-0
TOTAL: 1144
Here the "BLOCKS" correspond to the block numbering we are talking
about, right? It always start at 0 per-file. "IND" is the indirect
block. But what is "DIND"? "2317946" is the physical block number
right? And what is the zero after the "2317946"?
On Tue, Dec 23, 2008 at 10:56 AM, Mike Snitzer <snitzer@xxxxxxxxx> wrote:
>
> On Sat, Dec 20, 2008 at 8:25 PM, Peter Teoh <htmldeveloper@xxxxxxxxx> wrote:
> > On Sat, Dec 20, 2008 at 11:43 PM, Rohit Sharma <imreckless@xxxxxxxxx> wrote:
> >> A little confusion.
> >>
> >> Just refer this structure in linux/ext2_fs_sb.h
> >>
> >> struct ext2_block_alloc_info {
> >> 46 /* information about reservation window */
> >> 47 struct ext2_reserve_window_node rsv_window_node;
> >> 48 /*
> >> 49 * was i_next_alloc_block in ext2_inode_info
> >> 50 * is the logical (file-relative) number of the
> >> 51 * most-recently-allocated block in this file.
> >> 52 * We use this for detecting linearly ascending allocation requests.
> >> 53 */
> >> 54 __u32 last_alloc_logical_block;
> >
> > if i interpret the meaning of "file-relative logical number"
> > correctly, and since one-file-one-inode concept, then it means that it
> > should mean inode-relative logical block number.
> >
> >> 55 /*
> >> 56 * Was i_next_alloc_goal in ext2_inode_info
> >> 57 * is the *physical* companion to i_next_alloc_block.
> >> 58 * it the the physical block number of the block which was
> >
> >> inode1 has logical blocks 0 1 2 , physical 22 23 24
> >> inode2 has logical blocks 0 1 2 , physical 34 35 50
> >>
> >
> > as per comment above, the sequence above looks likely, but then this
> > is my guess again.
>
> You are correct. last_alloc_logical_block is used to detect if the
> write workload against a given inode is sequential (the current
> logical block is last_alloc_logical_block+1).
>
> Mike
--
Regards,
Peter Teoh
Ernest Hemingway - "Never mistake motion for action."
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