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authorGao Xiang <gaoxiang25@huawei.com>2019-09-22 02:43:55 +0800
committerGao Xiang <gaoxiang25@huawei.com>2019-10-01 04:54:33 +0800
commit55252ab72b774119afedfdc6d1f142ffa2a9b818 (patch)
treeb5dede17c84b402f3fde651885ddd89705a41cc8 /fs
parent6927cc05c2b067d4ca8ab6aeaa3b4544bea26ef8 (diff)
downloadlinux-55252ab72b774119afedfdc6d1f142ffa2a9b818.tar.gz
erofs: fix erofs_get_meta_page locking due to a cleanup
After doing more drop_caches stress test on
our products, I found the mistake introduced by
a very recent cleanup [1].

The current rule is that "erofs_get_meta_page"
should be returned with page locked (although
it's mostly unnecessary for read-only fs after
pages are PG_uptodate), but a fix should be
done for this.

[1] https://lore.kernel.org/r/20190904020912.63925-26-gaoxiang25@huawei.com
Fixes: 618f40ea026b ("erofs: use read_cache_page_gfp for erofs_get_meta_page")
Reviewed-by: Chao Yu <yuchao0@huawei.com>
Link: https://lore.kernel.org/r/20190921184355.149928-1-gaoxiang25@huawei.com
Signed-off-by: Gao Xiang <gaoxiang25@huawei.com>
Diffstat (limited to 'fs')
-rw-r--r--fs/erofs/data.c10
1 files changed, 7 insertions, 3 deletions
diff --git a/fs/erofs/data.c b/fs/erofs/data.c
index 8a9fcbd0e8ac..fc3a8d8064f8 100644
--- a/fs/erofs/data.c
+++ b/fs/erofs/data.c
@@ -34,11 +34,15 @@ static void erofs_readendio(struct bio *bio)
 
 struct page *erofs_get_meta_page(struct super_block *sb, erofs_blk_t blkaddr)
 {
-	struct inode *const bd_inode = sb->s_bdev->bd_inode;
-	struct address_space *const mapping = bd_inode->i_mapping;
+	struct address_space *const mapping = sb->s_bdev->bd_inode->i_mapping;
+	struct page *page;
 
-	return read_cache_page_gfp(mapping, blkaddr,
+	page = read_cache_page_gfp(mapping, blkaddr,
 				   mapping_gfp_constraint(mapping, ~__GFP_FS));
+	/* should already be PageUptodate */
+	if (!IS_ERR(page))
+		lock_page(page);
+	return page;
 }
 
 static int erofs_map_blocks_flatmode(struct inode *inode,