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: Wed, 14 Aug 2024 19:11:19 +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 uniformly calling nilfs_segctor_abort_construction()
on failure of each step in the loop in nilfs_segctor_do_construct(),
having it clean up logs and segment usages according to progress, and
correcting the conditions for calling nilfs_redirty_inodes() to ensure
that the NILFS_I_COLLECTED flag is cleared.
Link: https://lkml.kernel.org/r/20240814101119.4070-1-konishi.ryusuke@xxxxxxxxx
Fixes: a694291a6211 ("nilfs2: separate wait function from nilfs_segctor_write")
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@xxxxxxxxx>
Tested-by: Ryusuke Konishi <konishi.ryusuke@xxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
fs/nilfs2/segment.c | 10 ++++++----
1 file changed, 6 insertions(+), 4 deletions(-)
--- a/fs/nilfs2/segment.c~nilfs2-fix-state-management-in-error-path-of-log-writing-function
+++ a/fs/nilfs2/segment.c
@@ -1812,6 +1812,9 @@ static void nilfs_segctor_abort_construc
nilfs_abort_logs(&logs, ret ? : err);
list_splice_tail_init(&sci->sc_segbufs, &logs);
+ if (list_empty(&logs))
+ return; /* if the first segment buffer preparation failed */
+
nilfs_cancel_segusage(&logs, nilfs->ns_sufile);
nilfs_free_incomplete_logs(&logs, nilfs);
@@ -2056,7 +2059,7 @@ 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 +2123,9 @@ 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-protect-references-to-superblock-parameters-exposed-in-sysfs.patch
nilfs2-fix-missing-cleanup-on-rollforward-recovery-error.patch
nilfs2-fix-state-management-in-error-path-of-log-writing-function.patch
