d/freebsd-nq
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

Fix bug introduced in rev 1.434:

Browse Source 
When avoiding the zeroing of "bogus_page" when it appears in a buf,
be sure to advance the pointers into the data for successive pages.

The bug caused file corruption when read(2)ing from a "hole" in a
file where a previous page of the read block had already been faulted
in: fsx tripped up on this pretty quickly. The particular access
pattern is probably pretty unusual, so other applications probably
wouldn't have had problems, but you'd never know.

Reviewed By: alc@
This commit is contained in:
Peter Edwards 2004-07-06 23:40:40 +00:00
parent af73aa7cce
commit 0f01586867
1 changed files with 3 additions and 3 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

6
sys/kern/vfs_bio.c
View File

@ -3553,13 +3553,13 @@ vfs_bio_clrbuf(struct buf *bp)
}
ea = sa = bp->b_data;
for(i=0;i<bp->b_npages;i++,sa=ea) {
if (bp->b_pages[i] == bogus_page)
continue;
j = ((vm_offset_t)sa & PAGE_MASK) / DEV_BSIZE;
ea = (caddr_t)trunc_page((vm_offset_t)sa + PAGE_SIZE);
ea = (caddr_t)(vm_offset_t)ulmin(
(u_long)(vm_offset_t)ea,
(u_long)(vm_offset_t)bp->b_data + bp->b_bufsize);
if (bp->b_pages[i] == bogus_page)
continue;
j = ((vm_offset_t)sa & PAGE_MASK) / DEV_BSIZE;
mask = ((1 << ((ea - sa) / DEV_BSIZE)) - 1) << j;
VM_OBJECT_LOCK_ASSERT(bp->b_pages[i]->object, MA_OWNED);
if ((bp->b_pages[i]->valid & mask) == mask)