From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from aserp2130.oracle.com ([141.146.126.79]:43740 "EHLO aserp2130.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726266AbfD0BYO (ORCPT ); Fri, 26 Apr 2019 21:24:14 -0400 Date: Fri, 26 Apr 2019 18:24:06 -0700 From: "Darrick J. Wong" Subject: Re: [PATCH] xfs_db: Scan entire file system when using 'frag' Message-ID: <20190427012406.GO178290@magnolia> References: <20190426225920.34359-1-jorgeguerra@gmail.com> <4c0ed0bf-c980-9379-3816-c8e5dddd61b5@sandeen.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4c0ed0bf-c980-9379-3816-c8e5dddd61b5@sandeen.net> Sender: linux-xfs-owner@vger.kernel.org List-ID: List-Id: xfs To: Eric Sandeen Cc: Jorge Guerra , linux-xfs@vger.kernel.org, osandov@osandov.com, Jorge Guerra On Fri, Apr 26, 2019 at 07:13:49PM -0500, Eric Sandeen wrote: > On 4/26/19 5:59 PM, Jorge Guerra wrote: > > From: Jorge Guerra > > > > While running the 'frag' command of 'xfs_db' we noticed that the > > tool is not scanning all the files in the file system. We noticed > > this when we modified the tool to print the inodes of all the files > > scanned. For example: > > > > $ find /mnt/xfsdisk -type f | wc -l > > 1782674 > > $ xfs_db -r -c frag /dev/sdXX | grep MB | awk '{print $5}' | paste -s -d+ | bc > > 656818 > > > > Upon inspecting the code we noticed that the scanfunc_ino function > > stops processing a given inode block once it encounters a free leaf. > > However, in practice we see that inodes are necessarily always layed > > out contiguously on the leaf node. This resulted in the 'frag' > > command skipping some valid inodes. > > > > In this change we modify the scanfunc_ino function to skip freed > > inodes. With the change in place we ran the same experiment again > > and noticed a more accurate file count: > > > > $ find /mnt/d0 -type f | wc -l > > 1810442 > > $ xfs_db -r -c frag /dev/sdXX | grep MB | awk '{print $5}' | paste -s -d+ | bc > > 1810442 > > > > Signed-off-by: Jorge Guerra > > This looks right, but I'll warn you that xfs_db's frag command is largely > useless in the first place. ;) I was looking through the manpages for the part where it says frag is useless but couldn't find it. Oh well. :( Reviewed-by: Darrick J. Wong --D > > Also, I think: > > Fixes: 2a5eb70c ("xfs_db: teach the frag command about sparse inode chunks") > > Reviewed-by: Eric Sandeen > > Thanks! > > > --- > > db/frag.c | 2 +- > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > diff --git a/db/frag.c b/db/frag.c > > index 5f33cb73..91395234 100644 > > --- a/db/frag.c > > +++ b/db/frag.c > > @@ -507,7 +507,7 @@ scanfunc_ino( > > > > for (j = 0; j < inodes_per_buf; j++) { > > if (XFS_INOBT_IS_FREE_DISK(&rp[i], ioff + j)) > > - goto next_buf; > > + continue; > > dip = (xfs_dinode_t *)((char *)iocur_top->data + > > ((off + j) << mp->m_sb.sb_inodelog)); > > process_inode(agf, agino + ioff + j, dip); > >