From 8b4216018bdbfbb1b76150d202b15ee68c38e991 Mon Sep 17 00:00:00 2001 From: Abhijith Das Date: Sun, 4 Jul 2010 01:33:24 -0400 Subject: [PATCH] GFS2: BUG in gfs2_adjust_quota HighMem pages on i686 do not get mapped to the buffer_heads and this was causing a NULL pointer dereference when we were trying to memset page buffers to zero. We now use zero_user() that kmaps the page and directly manipulates page data. This patch also fixes a boundary condition that was incorrect. Signed-off-by: Abhi Das Signed-off-by: Steven Whitehouse --- fs/gfs2/quota.c | 8 +++----- 1 file changed, 3 insertions(+), 5 deletions(-) diff --git a/fs/gfs2/quota.c b/fs/gfs2/quota.c index 49667d6..b256d6f 100644 --- a/fs/gfs2/quota.c +++ b/fs/gfs2/quota.c @@ -694,10 +694,8 @@ get_a_page: if (!buffer_mapped(bh)) goto unlock_out; /* If it's a newly allocated disk block for quota, zero it */ - if (buffer_new(bh)) { - memset(bh->b_data, 0, bh->b_size); - set_buffer_uptodate(bh); - } + if (buffer_new(bh)) + zero_user(page, pos - blocksize, bh->b_size); } if (PageUptodate(page)) @@ -723,7 +721,7 @@ get_a_page: /* If quota straddles page boundary, we need to update the rest of the * quota at the beginning of the next page */ - if (offset != 0) { /* first page, offset is closer to PAGE_CACHE_SIZE */ + if ((offset + sizeof(struct gfs2_quota)) > PAGE_CACHE_SIZE) { ptr = ptr + nbytes; nbytes = sizeof(struct gfs2_quota) - nbytes; offset = 0; -- 2.7.4