* + fat-fix-parent-link-count-when-replacing-a-sibling-directory.patch added to mm-nonmm-unstable branch
@ 2026-10-29 22:16 Andrew Morton
0 siblings, 0 replies; 2+ messages in thread
From: Andrew Morton @ 2026-10-29 22:16 UTC (permalink / raw)
To: mm-commits, hirofumi, brauner, dennylin0707, akpm
The patch titled
Subject: fat: fix parent link count when replacing a sibling directory
has been added to the -mm mm-nonmm-unstable branch. Its filename is
fat-fix-parent-link-count-when-replacing-a-sibling-directory.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/fat-fix-parent-link-count-when-replacing-a-sibling-directory.patch
This patch will later appear in the mm-nonmm-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 various
branches at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
and is updated there most days
------------------------------------------------------
From: Hungyu Lin <dennylin0707@gmail.com>
Subject: fat: fix parent link count when replacing a sibling directory
Date: Wed, 28 Oct 2026 21:16:25 +0000
vfat_rename() and do_msdos_rename() adjust parent link counts only when
updating the dotdot entry for a move between different parents. Replacing
an existing empty directory in the same parent also removes a
subdirectory, but leaves the parent's link count unchanged.
For example, renaming one of two sibling directories over the other
leaves the parent with four links instead of three. stat and ls report
the stale count, and find -links 3 does not match the parent.
Drop the parent's link count for this case after the source entry has
been removed successfully. Leave cross-parent renames, regular files
and the existing error paths unchanged.
Link: https://lore.kernel.org/20261028211626.26103-1-dennylin0707@gmail.com
Signed-off-by: Hungyu Lin <dennylin0707@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Cc: Christian Brauner <brauner@kernel.org>
---
fs/fat/namei_msdos.c | 2 ++
fs/fat/namei_vfat.c | 2 ++
2 files changed, 4 insertions(+)
--- a/fs/fat/namei_msdos.c~fat-fix-parent-link-count-when-replacing-a-sibling-directory
+++ a/fs/fat/namei_msdos.c
@@ -565,6 +565,8 @@ static int do_msdos_rename(struct inode
(void)sync_inode_metadata(old_dir, 1);
if (new_inode) {
+ if (is_dir && old_dir == new_dir)
+ drop_nlink(old_dir);
drop_nlink(new_inode);
if (is_dir)
drop_nlink(new_inode);
--- a/fs/fat/namei_vfat.c~fat-fix-parent-link-count-when-replacing-a-sibling-directory
+++ a/fs/fat/namei_vfat.c
@@ -1011,6 +1011,8 @@ static int vfat_rename(struct inode *old
vfat_update_dir_metadata(old_dir, &ts);
if (new_inode) {
+ if (is_dir && old_dir == new_dir)
+ drop_nlink(old_dir);
drop_nlink(new_inode);
if (is_dir)
drop_nlink(new_inode);
_
Patches currently in -mm which might be from dennylin0707@gmail.com are
mm-page-writeback-avoid-32-bit-overflow-in-dirty-threshold-shares.patch
mm-migrate-untag-addresses-when-querying-page-nodes.patch
fat-fix-parent-link-count-when-replacing-a-sibling-directory.patch
^ permalink raw reply [flat|nested] 2+ messages in thread
* + fat-fix-parent-link-count-when-replacing-a-sibling-directory.patch added to mm-nonmm-unstable branch
@ 2026-10-29 22:16 Andrew Morton
0 siblings, 0 replies; 2+ messages in thread
From: Andrew Morton @ 2026-10-29 22:16 UTC (permalink / raw)
To: mm-commits, hirofumi, brauner, dennylin0707, akpm
The patch titled
Subject: fat: fix parent link count when replacing a sibling directory
has been added to the -mm mm-nonmm-unstable branch. Its filename is
fat-fix-parent-link-count-when-replacing-a-sibling-directory.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/fat-fix-parent-link-count-when-replacing-a-sibling-directory.patch
This patch will later appear in the mm-nonmm-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 various
branches at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
and is updated there most days
------------------------------------------------------
From: Hungyu Lin <dennylin0707@gmail.com>
Subject: fat: fix parent link count when replacing a sibling directory
Date: Thu, 29 Oct 2026 20:23:52 +0000
vfat_rename() and do_msdos_rename() adjust parent link counts only when
updating the dotdot entry for a move between different parents. Replacing
an existing empty directory in the same parent also removes a
subdirectory, but leaves the parent's link count unchanged.
For example, renaming one of two sibling directories over the other
leaves the parent with four links instead of three. stat and ls report
the stale count, and find -links 3 does not match the parent.
Drop the parent's link count for this case after the source entry has
been removed successfully. Leave cross-parent renames, regular files
and the existing error paths unchanged.
As in rmdir, check that the parent's link count is at least three before
decrementing it. Report a filesystem error if corrupted directory entries
have left the count too low, rather than reducing it below two.
Link: https://lore.kernel.org/20261029202352.59890-1-dennylin0707@gmail.com
Signed-off-by: Hungyu Lin <dennylin0707@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Cc: Christian Brauner <brauner@kernel.org>
---
fs/fat/namei_msdos.c | 8 ++++++++
fs/fat/namei_vfat.c | 8 ++++++++
2 files changed, 16 insertions(+)
--- a/fs/fat/namei_msdos.c~fat-fix-parent-link-count-when-replacing-a-sibling-directory
+++ a/fs/fat/namei_msdos.c
@@ -565,6 +565,14 @@ static int do_msdos_rename(struct inode
(void)sync_inode_metadata(old_dir, 1);
if (new_inode) {
+ if (is_dir && old_dir == new_dir) {
+ if (old_dir->i_nlink >= 3)
+ drop_nlink(old_dir);
+ else
+ fat_fs_error(old_dir->i_sb,
+ "parent dir link count too low (%u)",
+ old_dir->i_nlink);
+ }
drop_nlink(new_inode);
if (is_dir)
drop_nlink(new_inode);
--- a/fs/fat/namei_vfat.c~fat-fix-parent-link-count-when-replacing-a-sibling-directory
+++ a/fs/fat/namei_vfat.c
@@ -1011,6 +1011,14 @@ static int vfat_rename(struct inode *old
vfat_update_dir_metadata(old_dir, &ts);
if (new_inode) {
+ if (is_dir && old_dir == new_dir) {
+ if (old_dir->i_nlink >= 3)
+ drop_nlink(old_dir);
+ else
+ fat_fs_error(old_dir->i_sb,
+ "parent dir link count too low (%u)",
+ old_dir->i_nlink);
+ }
drop_nlink(new_inode);
if (is_dir)
drop_nlink(new_inode);
_
Patches currently in -mm which might be from dennylin0707@gmail.com are
mm-page-writeback-avoid-32-bit-overflow-in-dirty-threshold-shares.patch
mm-migrate-untag-addresses-when-querying-page-nodes.patch
fat-fix-parent-link-count-when-replacing-a-sibling-directory.patch
^ permalink raw reply [flat|nested] 2+ messages in thread
end of thread, other threads:[~2026-10-29 22:16 UTC | newest]
Thread overview: 2+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2026-10-29 22:16 + fat-fix-parent-link-count-when-replacing-a-sibling-directory.patch added to mm-nonmm-unstable branch Andrew Morton
-- strict thread matches above, loose matches on Subject: below --
2026-10-29 22:16 Andrew Morton
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.