Hi Rohit,
On Sat, Dec 20, 2008 at 9:13 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;
> 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
> most-recentl
> 59 * allocated to this file. This give us the goal (target)
> for the next
Look at the comment, this clearly suggests that its a file specific information.
So, its specific to inode.
> 60 * allocation when we detect linearly ascending requests.
> 61 */
It can be only to a file, as for the file system it is already ascending.
> 62 ext2_fsblk_t last_alloc_physical_block;
> 63};
>
>
> this information is maintained by ext2 for every inode.
>
> here last_alloc_logical_block is for every inode or its for filesystem.
>
inode.
> I mean if we are allocating blocks for inode
> it can be block no. 0 to n logically
> and physically like 23 24 25 34 36 40 41 42
>
> i mean to say
>
> is it like
>
> inode1 has logical blocks 1 2 3 , physical 22 23 24
> inode2 has logical blocks 4 5 6 , physical 34 35 50
>
This is correct.
> OR
>
> inode1 has logical blocks 0 1 2 , physical 22 23 24
> inode2 has logical blocks 0 1 2 , physical 34 35 50
>
You cannot have the same logical block assigned to two inodes with
diff physical blocks, probably. Doesn't make sense to me.
> ??
>
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>
--
Regards,
Sandeep.
"To learn is to change. Education is a process that changes the learner."
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