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...

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@gmail.com 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@gmail.com Signed-off-by: Ryusuke Konishi konishi.ryusuke@gmail.com Fixes: a694291a6211 ("nilfs2: separate wait function from nilfs_segctor_write") Tested-by: Ryusuke Konishi konishi.ryusuke@gmail.com Cc: stable@vger.kernel.org Signed-off-by: Andrew Morton akpm@linux-foundation.org ---

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@gmail.com are

nilfs2-fix-state-management-in-error-path-of-log-writing-function.patch