From: =?ISO-8859-1?Q?Fr=E9d=E9ric_Boh=E9?= Subject: Re: [PATCH v2] ext4: fix initialization of UNINIT bitmap blocks Date: Mon, 15 Sep 2008 16:30:26 +0200 Message-ID: <1221489026.6733.36.camel@frecb007923.frec.bull.fr> References: <1221478895.6733.26.camel@frecb007923.frec.bull.fr> <1221481007.6733.32.camel@frecb007923.frec.bull.fr> <20080915133604.GA6548@skywalker> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Cc: "linux-ext4@vger.kernel.org" To: "Aneesh Kumar K.V" Return-path: Received: from ecfrec.frec.bull.fr ([129.183.4.8]:45606 "EHLO ecfrec.frec.bull.fr" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752890AbYIOO3M (ORCPT ); Mon, 15 Sep 2008 10:29:12 -0400 In-Reply-To: <20080915133604.GA6548@skywalker> Sender: linux-ext4-owner@vger.kernel.org List-ID: Le lundi 15 septembre 2008 =C3=A0 19:06 +0530, Aneesh Kumar K.V a =C3=A9= crit : > On Mon, Sep 15, 2008 at 02:16:47PM +0200, Fr=C3=A9d=C3=A9ric Boh=C3=A9= wrote: > > From: Frederic Bohe > >=20 > > Do not rely on buffer head's uptodate flag to initialize > > uninitialized bitmap blocks. > >=20 > > Signed-off-by: Frederic Bohe > > --- > > Sorry there was a copy/paste error in the previous mail ! > >=20 > > This patch makes sure to initialize uninited bitmap blocks. > > These are two test cases where bugs appear because of uninited bloc= ks : > >=20 > > 1- This test case lead to uninited block bitmap and an error messag= e > > from the mballocator during the second dd. > >=20 > > dd if=3D/dev/urandom of=3D/dev/md0 bs=3D1M count=3D300 > > mkfs.ext4 -t ext4dev /dev/md0 1G > > mount -t ext4dev /dev/md0 /mnt/test > > resize2fs /dev/md0 2G > > dd if=3D/dev/zero of=3D/mnt/test/dummy bs=3D1M count=3D1500 > >=20 > > Note that the first dd is to make sure we have random garbage in th= e > > uninited blocks. If not, you could miss the issue depending what wa= s in > > those blocks before running mkfs. > >=20 > > 2- This test case lead to uninited inode bitmap blocks, making it > > impossible to use all the inodes of the fs. > >=20 > > dd if=3D/dev/urandom of=3D/dev/md0 bs=3D1M count=3D20 > > mkfs.ext4 -t ext4dev /dev/md0 10M > > mount -t ext4dev /dev/md0 /mnt/test > > resize2fs /dev/md0 20M > > for i in $(seq 1 3800); do touch /mnt/test/file${i} 2>&1; done > >=20 > > balloc.c | 4 +++- > > ialloc.c | 4 +++- > > mballoc.c | 4 +++- > > 3 files changed, 9 insertions(+), 3 deletions(-) > >=20 > > Index: linux-2.6.27-rc5+patch_queue/fs/ext4/balloc.c > > =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D > > --- linux-2.6.27-rc5+patch_queue.orig/fs/ext4/balloc.c 2008-09-15 1= 0:59:27.000000000 +0200 > > +++ linux-2.6.27-rc5+patch_queue/fs/ext4/balloc.c 2008-09-15 14:03:= 04.000000000 +0200 > > @@ -318,9 +318,11 @@ ext4_read_block_bitmap(struct super_bloc > > block_group, bitmap_blk); > > return NULL; > > } > > - if (bh_uptodate_or_lock(bh)) > > + if (buffer_uptodate(bh) && > > + !(desc->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT))) > > return bh; > >=20 > > + lock_buffer(bh); > > spin_lock(sb_bgl_lock(EXT4_SB(sb), block_group)); > > if (desc->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT)) { > > ext4_init_block_bitmap(sb, bh, block_group, desc); >=20 > Why ? I guess resize should mark those buffer_heads as not uptodate s= o > that we do a reinit of block bitmap again later. The above change wil= l > result in calling ext4_init_block_bitmap everytime we do a > read_block_bitmap on an uninit group Thanks for your comment Aneesh. I thought ext4_init_block_bitmap was setting the EXT4_BG_BLOCK_UNINIT flags, but it seems it is not true. I will try to fix it on the resize side. >=20 >=20 >=20 >=20 > > Index: linux-2.6.27-rc5+patch_queue/fs/ext4/ialloc.c > > =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D > > --- linux-2.6.27-rc5+patch_queue.orig/fs/ext4/ialloc.c 2008-09-15 1= 0:59:27.000000000 +0200 > > +++ linux-2.6.27-rc5+patch_queue/fs/ext4/ialloc.c 2008-09-15 11:12:= 16.000000000 +0200 > > @@ -115,9 +115,11 @@ ext4_read_inode_bitmap(struct super_bloc > > block_group, bitmap_blk); > > return NULL; > > } > > - if (bh_uptodate_or_lock(bh)) > > + if (buffer_uptodate(bh) && > > + !(desc->bg_flags & cpu_to_le16(EXT4_BG_INODE_UNINIT))) > > return bh; > >=20 > > + lock_buffer(bh); > > spin_lock(sb_bgl_lock(EXT4_SB(sb), block_group)); > > if (desc->bg_flags & cpu_to_le16(EXT4_BG_INODE_UNINIT)) { > > ext4_init_inode_bitmap(sb, bh, block_group, desc); > > Index: linux-2.6.27-rc5+patch_queue/fs/ext4/mballoc.c > > =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D > > --- linux-2.6.27-rc5+patch_queue.orig/fs/ext4/mballoc.c 2008-09-15 = 10:59:27.000000000 +0200 > > +++ linux-2.6.27-rc5+patch_queue/fs/ext4/mballoc.c 2008-09-15 14:02= :44.000000000 +0200 > > @@ -785,9 +785,11 @@ static int ext4_mb_init_cache(struct pag > > if (bh[i] =3D=3D NULL) > > goto out; > >=20 > > - if (bh_uptodate_or_lock(bh[i])) > > + if (buffer_uptodate(bh[i]) && > > + !(desc->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT))) > > continue; > >=20 > > + lock_buffer(bh[i]); > > spin_lock(sb_bgl_lock(EXT4_SB(sb), first_group + i)); > > if (desc->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT)) { > > ext4_init_block_bitmap(sb, bh[i], > >=20 >=20 > -aneesh >=20 -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" i= n the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html