| From 63232c61c5a8d0327b798af303311f023704eddf Mon Sep 17 00:00:00 2001 |
| From: Sasha Levin <sashal@kernel.org> |
| Date: Thu, 14 Apr 2022 17:52:39 +0200 |
| Subject: gfs2: Fix filesystem block deallocation for short writes |
| |
| From: Andreas Gruenbacher <agruenba@redhat.com> |
| |
| [ Upstream commit d031a8866e709c9d1ee5537a321b6192b4d2dc5b ] |
| |
| When a write cannot be carried out in full, gfs2_iomap_end() releases |
| blocks that have been allocated for this write but haven't been used. |
| |
| To compute the end of the allocation, gfs2_iomap_end() incorrectly |
| rounded the end of the attempted write down to the next block boundary |
| to arrive at the end of the allocation. It would have to round up, but |
| the end of the allocation is also available as iomap->offset + |
| iomap->length, so just use that instead. |
| |
| In addition, use round_up() for computing the start of the unused range. |
| |
| Fixes: 64bc06bb32ee ("gfs2: iomap buffered write support") |
| Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com> |
| Signed-off-by: Sasha Levin <sashal@kernel.org> |
| --- |
| fs/gfs2/bmap.c | 11 +++++------ |
| 1 file changed, 5 insertions(+), 6 deletions(-) |
| |
| diff --git a/fs/gfs2/bmap.c b/fs/gfs2/bmap.c |
| index 53ba5019ad06..150cec85c416 100644 |
| --- a/fs/gfs2/bmap.c |
| +++ b/fs/gfs2/bmap.c |
| @@ -1168,13 +1168,12 @@ static int gfs2_iomap_end(struct inode *inode, loff_t pos, loff_t length, |
| |
| if (length != written && (iomap->flags & IOMAP_F_NEW)) { |
| /* Deallocate blocks that were just allocated. */ |
| - loff_t blockmask = i_blocksize(inode) - 1; |
| - loff_t end = (pos + length) & ~blockmask; |
| + loff_t hstart = round_up(pos + written, i_blocksize(inode)); |
| + loff_t hend = iomap->offset + iomap->length; |
| |
| - pos = (pos + written + blockmask) & ~blockmask; |
| - if (pos < end) { |
| - truncate_pagecache_range(inode, pos, end - 1); |
| - punch_hole(ip, pos, end - pos); |
| + if (hstart < hend) { |
| + truncate_pagecache_range(inode, hstart, hend - 1); |
| + punch_hole(ip, hstart, hend - hstart); |
| } |
| } |
| |
| -- |
| 2.35.1 |
| |