linux-kernel - [PATCH 19/25] ext4: support large block size in mpage_prepare_extent_to

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Message-Id: <20251025032221.2905818-20-libaokun@huaweicloud.com>
Date: Sat, 25 Oct 2025 11:22:15 +0800
From: libaokun@...weicloud.com
To: linux-ext4@...r.kernel.org
Cc: tytso@....edu,
	adilger.kernel@...ger.ca,
	jack@...e.cz,
	linux-kernel@...r.kernel.org,
	kernel@...kajraghav.com,
	mcgrof@...nel.org,
	linux-fsdevel@...r.kernel.org,
	linux-mm@...ck.org,
	yi.zhang@...wei.com,
	yangerkun@...wei.com,
	chengzhihao1@...wei.com,
	libaokun1@...wei.com,
	libaokun@...weicloud.com
Subject: [PATCH 19/25] ext4: support large block size in mpage_prepare_extent_to_map()

From: Baokun Li <libaokun1@...wei.com>

Use the EXT4_P_TO_LBLK/EXT4_LBLK_TO_P macros to complete the conversion
between folio indexes and blocks to avoid negative left/right shifts after
supporting blocksize greater than PAGE_SIZE.

Signed-off-by: Baokun Li <libaokun1@...wei.com>
Reviewed-by: Zhang Yi <yi.zhang@...wei.com>
---
 fs/ext4/inode.c | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index cbf04b473ae7..ce48cc6780a3 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -2610,7 +2610,6 @@ static int mpage_prepare_extent_to_map(struct mpage_da_data *mpd)
 	pgoff_t end = mpd->end_pos >> PAGE_SHIFT;
 	xa_mark_t tag;
 	int i, err = 0;
-	int blkbits = mpd->inode->i_blkbits;
 	ext4_lblk_t lblk;
 	struct buffer_head *head;
 	handle_t *handle = NULL;
@@ -2649,7 +2648,7 @@ static int mpage_prepare_extent_to_map(struct mpage_da_data *mpd)
 			 */
 			if (mpd->wbc->sync_mode == WB_SYNC_NONE &&
 			    mpd->wbc->nr_to_write <=
-			    mpd->map.m_len >> (PAGE_SHIFT - blkbits))
+			    EXT4_LBLK_TO_P(mpd->inode, mpd->map.m_len))
 				goto out;
 
 			/* If we can't merge this page, we are done. */
@@ -2727,8 +2726,7 @@ static int mpage_prepare_extent_to_map(struct mpage_da_data *mpd)
 				mpage_folio_done(mpd, folio);
 			} else {
 				/* Add all dirty buffers to mpd */
-				lblk = ((ext4_lblk_t)folio->index) <<
-					(PAGE_SHIFT - blkbits);
+				lblk = EXT4_P_TO_LBLK(mpd->inode, folio->index);
 				head = folio_buffers(folio);
 				err = mpage_process_page_bufs(mpd, head, head,
 						lblk);
-- 
2.46.1