4.19-stable review patch. If anyone has any objections, please let me know.
------------------
From: Ryusuke Konishi konishi.ryusuke@gmail.com
commit 6576dd6695f2afca3f4954029ac4a64f82ba60ab upstream.
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@gmail.com Fixes: a694291a6211 ("nilfs2: separate wait function from nilfs_segctor_write") Signed-off-by: Ryusuke Konishi konishi.ryusuke@gmail.com Tested-by: Ryusuke Konishi konishi.ryusuke@gmail.com Cc: stable@vger.kernel.org Signed-off-by: Andrew Morton akpm@linux-foundation.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- fs/nilfs2/segment.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-)
--- a/fs/nilfs2/segment.c +++ b/fs/nilfs2/segment.c @@ -1828,6 +1828,9 @@ 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);
@@ -2072,7 +2075,7 @@ 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(); @@ -2135,10 +2138,9 @@ 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);