The patch titled
Subject: nilfs2: fix state management in error path of log writing function
has been added to the -mm mm-hotfixes-unstable branch. Its filename is
nilfs2-fix-state-management-in-error-path-of-log-writing-function.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/nilfs2-fix-state-management-in-error-path-of-log-writing-function.patch
This patch will later appear in the mm-hotfixes-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: Ryusuke Konishi <konishi.ryusuke@xxxxxxxxx>
Subject: nilfs2: fix state management in error path of log writing function
Date: Thu, 8 Aug 2024 08:07:42 +0900
After commit a694291a6211 ("nilfs2: separate wait function from
nilfs_segctor_write") was applied, the log writing function
nilfs_segctor_do_construct() was able to issue I/O requests continuously
even if user data blocks were split into multiple logs across segments,
but two potential flaws were introduced in its error handling.
First, if nilfs_segctor_begin_construction() fails while creating the
second or subsequent logs, the log writing function returns without
calling nilfs_segctor_abort_construction(), so the writeback flag set on
pages/folios will remain uncleared. This causes page cache operations to
hang waiting for the writeback flag. For example,
truncate_inode_pages_final(), which is called via nilfs_evict_inode() when
an inode is evicted from memory, will hang.
Second, the NILFS_I_COLLECTED flag set on normal inodes remain uncleared.
As a result, if the next log write involves checkpoint creation, that's
fine, but if a partial log write is performed that does not, inodes with
NILFS_I_COLLECTED set are erroneously removed from the "sc_dirty_files"
list, and their data and b-tree blocks may not be written to the device,
corrupting the block mapping.
Fix these issues by correcting the jump destination of the error branch in
nilfs_segctor_do_construct() and the condition for calling
nilfs_redirty_inodes(), which clears the NILFS_I_COLLECTED flag.
Link: https://lkml.kernel.org/r/20240807230742.11151-1-konishi.ryusuke@xxxxxxxxx
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@xxxxxxxxx>
Fixes: a694291a6211 ("nilfs2: separate wait function from nilfs_segctor_write")
Tested-by: Ryusuke Konishi <konishi.ryusuke@xxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
fs/nilfs2/segment.c | 7 +++----
1 file changed, 3 insertions(+), 4 deletions(-)
--- a/fs/nilfs2/segment.c~nilfs2-fix-state-management-in-error-path-of-log-writing-function
+++ a/fs/nilfs2/segment.c
@@ -2056,7 +2056,7 @@ static int nilfs_segctor_do_construct(st
err = nilfs_segctor_begin_construction(sci, nilfs);
if (unlikely(err))
- goto out;
+ goto failed;
/* Update time stamp */
sci->sc_seg_ctime = ktime_get_real_seconds();
@@ -2120,10 +2120,9 @@ static int nilfs_segctor_do_construct(st
return err;
failed_to_write:
- if (sci->sc_stage.flags & NILFS_CF_IFILE_STARTED)
- nilfs_redirty_inodes(&sci->sc_dirty_files);
-
failed:
+ if (mode == SC_LSEG_SR && nilfs_sc_cstage_get(sci) >= NILFS_ST_IFILE)
+ nilfs_redirty_inodes(&sci->sc_dirty_files);
if (nilfs_doing_gc())
nilfs_redirty_inodes(&sci->sc_gc_inodes);
nilfs_segctor_abort_construction(sci, nilfs, err);
_
Patches currently in -mm which might be from konishi.ryusuke@xxxxxxxxx are
nilfs2-fix-state-management-in-error-path-of-log-writing-function.patch
