From: "Rohit Sharma" Subject: Re: ext2_block_alloc_info Date: Sun, 21 Dec 2008 01:14:16 +0530 Message-ID: <2d08ef090812201144t63266826ob038c530ba9f66cd@mail.gmail.com> References: <2d08ef090812200743o47cd4abdwd9915653f6f4f3f7@mail.gmail.com> <37d33d830812201140r1bc64a83kdc3f27b3fa88cc1b@mail.gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Cc: Kernelnewbies , ext4 To: "Sandeep K Sinha" Return-path: Received: from wf-out-1314.google.com ([209.85.200.173]:3657 "EHLO wf-out-1314.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752921AbYLTToS (ORCPT ); Sat, 20 Dec 2008 14:44:18 -0500 Received: by wf-out-1314.google.com with SMTP id 27so1548184wfd.4 for ; Sat, 20 Dec 2008 11:44:16 -0800 (PST) In-Reply-To: <37d33d830812201140r1bc64a83kdc3f27b3fa88cc1b@mail.gmail.com> Content-Disposition: inline Sender: linux-ext4-owner@vger.kernel.org List-ID: Thanks for figuring it out. :) It was a very helpful information. On Sun, Dec 21, 2008 at 1:10 AM, Sandeep K Sinha wrote: > Hi Rohit, > > On Sat, Dec 20, 2008 at 9:13 PM, Rohit Sharma 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. >> ?? >> >> -- >> To unsubscribe from this list: send an email with >> "unsubscribe kernelnewbies" to ecartis@nl.linux.org >> Please read the FAQ at http://kernelnewbies.org/FAQ >> >> > > > > -- > Regards, > Sandeep. > > > > > > > "To learn is to change. Education is a process that changes the learner." >