On Mon, Nov 16, 2020 at 04:49:26PM +0100, gregkh@xxxxxxxxxxxxxxxxxxx wrote:
>
> The patch below does not apply to the 5.4-stable tree.
> If someone wants it applied there, or to any other stable or longterm
> tree, then please email the backport, including the original git commit
> id to <stable@xxxxxxxxxxxxxxx>.
Patch below generated against 5.4.67
> thanks,
>
> greg k-h
>
> ------------------ original commit in Linus's tree ------------------
>
> >From a1fbc6750e212c5675a4e48d7f51d44607eb8756 Mon Sep 17 00:00:00 2001
> From: "Matthew Wilcox (Oracle)" <willy@xxxxxxxxxxxxx>
> Date: Sun, 4 Oct 2020 19:04:26 +0100
> Subject: [PATCH] btrfs: fix potential overflow in cluster_pages_for_defrag on
> 32bit arch
>
> On 32-bit systems, this shift will overflow for files larger than 4GB as
> start_index is unsigned long while the calls to btrfs_delalloc_*_space
> expect u64.
>
> CC: stable@xxxxxxxxxxxxxxx # 4.4+
> Fixes: df480633b891 ("btrfs: extent-tree: Switch to new delalloc space reserve and release")
> Reviewed-by: Josef Bacik <josef@xxxxxxxxxxxxxx>
> Signed-off-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
> Reviewed-by: David Sterba <dsterba@xxxxxxxx>
> [ define the variable instead of repeating the shift ]
> Signed-off-by: David Sterba <dsterba@xxxxxxxx>
diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index 63394b450afc..4e3b71ec7492 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -1255,6 +1255,7 @@ static int cluster_pages_for_defrag(struct inode *inode,
u64 page_start;
u64 page_end;
u64 page_cnt;
+ u64 start = (u64)start_index << PAGE_SHIFT;
int ret;
int i;
int i_done;
@@ -1271,8 +1272,7 @@ static int cluster_pages_for_defrag(struct inode *inode,
page_cnt = min_t(u64, (u64)num_pages, (u64)file_end - start_index + 1);
ret = btrfs_delalloc_reserve_space(inode, &data_reserved,
- start_index << PAGE_SHIFT,
- page_cnt << PAGE_SHIFT);
+ start, page_cnt << PAGE_SHIFT);
if (ret)
return ret;
i_done = 0;
@@ -1361,8 +1361,7 @@ static int cluster_pages_for_defrag(struct inode *inode,
btrfs_mod_outstanding_extents(BTRFS_I(inode), 1);
spin_unlock(&BTRFS_I(inode)->lock);
btrfs_delalloc_release_space(inode, data_reserved,
- start_index << PAGE_SHIFT,
- (page_cnt - i_done) << PAGE_SHIFT, true);
+ start, (page_cnt - i_done) << PAGE_SHIFT, true);
}
@@ -1389,8 +1388,7 @@ static int cluster_pages_for_defrag(struct inode *inode,
put_page(pages[i]);
}
btrfs_delalloc_release_space(inode, data_reserved,
- start_index << PAGE_SHIFT,
- page_cnt << PAGE_SHIFT, true);
+ start, page_cnt << PAGE_SHIFT, true);
btrfs_delalloc_release_extents(BTRFS_I(inode), page_cnt << PAGE_SHIFT);
extent_changeset_free(data_reserved);
return ret;
