The patch titled
Subject: maple_tree: reload mas before the second call for mas_empty_area
has been added to the -mm mm-unstable branch. Its filename is
maple_tree-reload-mas-before-the-second-call-for-mas_empty_area.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/maple_tree-reload-mas-before-the-second-call-for-mas_empty_area.patch
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Before you just go and hit "reply", please:
a) Consider who else should be cc'ed
b) Prefer to cc a suitable mailing list as well
c) Ideally: find the original patch on the mailing list and do a
reply-to-all to that, adding suitable additional cc's
*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***
The -mm tree is included into linux-next via the mm-everything
branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
and is updated there every 2-3 working days
------------------------------------------------------
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.
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>
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 | 2 ++
1 file changed, 2 insertions(+)
--- a/lib/maple_tree.c~maple_tree-reload-mas-before-the-second-call-for-mas_empty_area
+++ a/lib/maple_tree.c
@@ -4335,6 +4335,7 @@ int mas_alloc_cyclic(struct ma_state *ma
{
unsigned long min = range_lo;
int ret = 0;
+ struct ma_state m = *mas;
range_lo = max(min, *next);
ret = mas_empty_area(mas, range_lo, range_hi, 1);
@@ -4343,6 +4344,7 @@ int mas_alloc_cyclic(struct ma_state *ma
ret = 1;
}
if (ret < 0 && range_lo > min) {
+ *mas = m;
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
maple_tree-reload-mas-before-the-second-call-for-mas_empty_area.patch
