linux-ext4 - [RFC PATCH 05/16] ext4: pass real delayed status into ext4_es_insert

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Message-Id: <20230824092619.1327976-6-yi.zhang@huaweicloud.com>
Date:   Thu, 24 Aug 2023 17:26:08 +0800
From:   Zhang Yi <yi.zhang@...weicloud.com>
To:     linux-ext4@...r.kernel.org
Cc:     tytso@....edu, adilger.kernel@...ger.ca, jack@...e.cz,
        yi.zhang@...wei.com, yi.zhang@...weicloud.com,
        chengzhihao1@...wei.com, yukuai3@...wei.com
Subject: [RFC PATCH 05/16] ext4: pass real delayed status into ext4_es_insert_extent()

From: Zhang Yi <yi.zhang@...wei.com>

Commit 'd2dc317d564a ("ext4: fix data corruption caused by unwritten and
delayed extents")' fix a data corruption issue by stop passing delayed
status into ext4_es_insert_extent() if the mapping range has been
written. This patch change it to still pass the real delayed status and
deal with the 'delayed && written' case in ext4_es_insert_extent(). If
the status have delayed bit is set, it means that the path of delayed
allocation is still running, and this insert process is not allocating
delayed allocated blocks.

Signed-off-by: Zhang Yi <yi.zhang@...wei.com>
---
 fs/ext4/extents_status.c | 13 +++++++------
 fs/ext4/inode.c          |  2 --
 2 files changed, 7 insertions(+), 8 deletions(-)

diff --git a/fs/ext4/extents_status.c b/fs/ext4/extents_status.c
index 3a004ed04570..62191c772b82 100644
--- a/fs/ext4/extents_status.c
+++ b/fs/ext4/extents_status.c
@@ -873,13 +873,14 @@ void ext4_es_insert_extent(struct inode *inode, ext4_lblk_t lblk,
 
 	BUG_ON(end < lblk);
 
+	/*
+	 * Insert extent as delayed and written which can potentially cause
+	 * data lose, and the extent has been written, it's safe to remove
+	 * the delayed flag even it's still delayed.
+	 */
 	if ((status & EXTENT_STATUS_DELAYED) &&
-	    (status & EXTENT_STATUS_WRITTEN)) {
-		ext4_warning(inode->i_sb, "Inserting extent [%u/%u] as "
-				" delayed and written which can potentially "
-				" cause data loss.", lblk, len);
-		WARN_ON(1);
-	}
+	    (status & EXTENT_STATUS_WRITTEN))
+		status &= ~EXTENT_STATUS_DELAYED;
 
 	newes.es_lblk = lblk;
 	newes.es_len = len;
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 6c490f05e2ba..82115d6656d3 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -563,7 +563,6 @@ int ext4_map_blocks(handle_t *handle, struct inode *inode,
 		status = map->m_flags & EXT4_MAP_UNWRITTEN ?
 				EXTENT_STATUS_UNWRITTEN : EXTENT_STATUS_WRITTEN;
 		if (!(flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE) &&
-		    !(status & EXTENT_STATUS_WRITTEN) &&
 		    ext4_es_scan_range(inode, &ext4_es_is_delayed, map->m_lblk,
 				       map->m_lblk + map->m_len - 1))
 			status |= EXTENT_STATUS_DELAYED;
@@ -673,7 +672,6 @@ int ext4_map_blocks(handle_t *handle, struct inode *inode,
 		status = map->m_flags & EXT4_MAP_UNWRITTEN ?
 				EXTENT_STATUS_UNWRITTEN : EXTENT_STATUS_WRITTEN;
 		if (!(flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE) &&
-		    !(status & EXTENT_STATUS_WRITTEN) &&
 		    ext4_es_scan_range(inode, &ext4_es_is_delayed, map->m_lblk,
 				       map->m_lblk + map->m_len - 1))
 			status |= EXTENT_STATUS_DELAYED;
-- 
2.39.2