From: Baokun Li <libaokun1@huawei.com>
In ext4_readdir(), page_cache_sync_readahead() is used to readahead mapped
physical blocks. With LBS support, this can lead to a negative right shift.
To fix this, the page index is now calculated by first converting the
physical block number (pblk) to a file position (pos) before converting
it to a page index. Also, the correct number of pages to readahead is now
passed.
Signed-off-by: Baokun Li <libaokun1@huawei.com>
Reviewed-by: Zhang Yi <yi.zhang@huawei.com>
---
fs/ext4/dir.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/fs/ext4/dir.c b/fs/ext4/dir.c
index d4164c507a90..256fe2c1d4c1 100644
--- a/fs/ext4/dir.c
+++ b/fs/ext4/dir.c
@@ -192,13 +192,13 @@ static int ext4_readdir(struct file *file, struct dir_context *ctx)
continue;
}
if (err > 0) {
- pgoff_t index = map.m_pblk >>
- (PAGE_SHIFT - inode->i_blkbits);
+ pgoff_t index = map.m_pblk << inode->i_blkbits >>
+ PAGE_SHIFT;
if (!ra_has_index(&file->f_ra, index))
page_cache_sync_readahead(
sb->s_bdev->bd_mapping,
- &file->f_ra, file,
- index, 1);
+ &file->f_ra, file, index,
+ 1 << EXT4_SB(sb)->s_min_folio_order);
file->f_ra.prev_pos = (loff_t)index << PAGE_SHIFT;
bh = ext4_bread(NULL, inode, map.m_lblk, 0);
if (IS_ERR(bh)) {
--
2.46.1