The quilt patch titled
Subject: maple_tree: reload mas before the second call for mas_empty_area
has been removed from the -mm tree. Its filename was
maple_tree-reload-mas-before-the-second-call-for-mas_empty_area.patch
This patch was dropped because it was merged into the mm-hotfixes-stable branch
of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
------------------------------------------------------
From: Yang Erkun <yangerkun@xxxxxxxxxx>
Subject: maple_tree: reload mas before the second call for mas_empty_area
Date: Sat, 14 Dec 2024 17:30:05 +0800
Change the LONG_MAX in simple_offset_add to 1024, and do latter:
[root@fedora ~]# mkdir /tmp/dir
[root@fedora ~]# for i in {1..1024}; do touch /tmp/dir/$i; done
touch: cannot touch '/tmp/dir/1024': Device or resource busy
[root@fedora ~]# rm /tmp/dir/123
[root@fedora ~]# touch /tmp/dir/1024
[root@fedora ~]# rm /tmp/dir/100
[root@fedora ~]# touch /tmp/dir/1025
touch: cannot touch '/tmp/dir/1025': Device or resource busy
After we delete file 100, actually this is a empty entry, but the latter
create failed unexpected.
mas_alloc_cyclic has two chance to find empty entry. First find the entry
with range range_lo and range_hi, if no empty entry exist, and range_lo >
min, retry find with range min and range_hi. However, the first call
mas_empty_area may mark mas as EBUSY, and the second call for
mas_empty_area will return false directly. Fix this by reload mas before
second call for mas_empty_area.
[Liam.Howlett@xxxxxxxxxx: fix mas_alloc_cyclic() second search]
Link: https://lore.kernel.org/all/20241216060600.287B4C4CED0@xxxxxxxxxxxxxxx/
Link: https://lkml.kernel.org/r/20241216190113.1226145-2-Liam.Howlett@xxxxxxxxxx
Link: https://lkml.kernel.org/r/20241214093005.72284-1-yangerkun@xxxxxxxxxxxxxxx
Fixes: 9b6713cc7522 ("maple_tree: Add mtree_alloc_cyclic()")
Signed-off-by: Yang Erkun <yangerkun@xxxxxxxxxx>
Signed-off-by: Liam R. Howlett <Liam.Howlett@xxxxxxxxxx>
Cc: Christian Brauner <brauner@xxxxxxxxxx>
Cc: Chuck Lever <chuck.lever@xxxxxxxxxx> says:
Cc: Liam R. Howlett <Liam.Howlett@xxxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
lib/maple_tree.c | 1 +
1 file changed, 1 insertion(+)
--- a/lib/maple_tree.c~maple_tree-reload-mas-before-the-second-call-for-mas_empty_area
+++ a/lib/maple_tree.c
@@ -4354,6 +4354,7 @@ int mas_alloc_cyclic(struct ma_state *ma
ret = 1;
}
if (ret < 0 && range_lo > min) {
+ mas_reset(mas);
ret = mas_empty_area(mas, min, range_hi, 1);
if (ret == 0)
ret = 1;
_
Patches currently in -mm which might be from yangerkun@xxxxxxxxxx are
