From patchwork Mon Jan 26 12:48:19 2009 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Subject: : make sure the buffer head members are zeroed out before using them. From: Manish Katiyar X-Patchwork-Id: 20275 Message-Id: To: Jan Kara Cc: ext4 , "Theodore Ts'o" , cmm@us.ibm.com Date: Mon, 26 Jan 2009 18:18:19 +0530 On Mon, Jan 26, 2009 at 6:03 PM, Manish Katiyar wrote: > On Mon, Jan 26, 2009 at 5:59 PM, Jan Kara wrote: >>> On Tue, Jan 20, 2009 at 10:36 PM, Manish Katiyar wrote: >>> > ext2_quota_read doesn't bzeroes tmp_bh before calling ext2_get_block() >>> > where we access the b_size of it. Since it is a local variable it >>> > might contain some garbage. Make sure it is filled with zero before >>> > passing. >>> >>> Hi Ted/mingming, >>> >>> Any feedback on this ?? >> Ops, sorry. I wanted to reply but first I wanted to research more >> whether we can set b_size to 0 and then forgot about it. Looking into >> other code (e.g. in fs/mpage.c or fs/buffer.c) I think it would be >> better to set b_size to sb->s_blocksize and be done with that. Mapping >> code does not need anything else set to a deterministic value so using >> memset is a bit overkill. > > Thanks Jan for your comments. Yes memset is an overkill. I did it just > because other users of ext2_get_block were doing the same way. Will > rework the patch with setting b_size as blocksize and send again. Here is the updated patch. compile tested. Signed-off-by : Manish Katiyar --- fs/ext2/super.c | 2 ++ 1 files changed, 2 insertions(+), 0 deletions(-) return err; @@ -1367,6 +1368,7 @@ static ssize_t ext2_quota_write(struct super_block *sb, int type, sb->s_blocksize - offset : towrite; tmp_bh.b_state = 0; + tmp_bh.b_size = sb->s_blocksize; err = ext2_get_block(inode, blk, &tmp_bh, 1); if (err < 0) goto out; diff --git a/fs/ext2/super.c b/fs/ext2/super.c index da8bdea..2a1c0c6 100644 --- a/fs/ext2/super.c +++ b/fs/ext2/super.c @@ -1328,6 +1328,7 @@ static ssize_t ext2_quota_read(struct super_block *sb, int type, char *data, sb->s_blocksize - offset : toread; tmp_bh.b_state = 0; + tmp_bh.b_size = sb->s_blocksize; err = ext2_get_block(inode, blk, &tmp_bh, 0); if (err < 0)