linux-kernel - [PATCH v2] fs: buffer: fix fully_mapped reset in block_read_full

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Message-Id: <1559317851-3861-1-git-send-email-liu.xiang6@zte.com.cn>
Date:   Fri, 31 May 2019 23:50:51 +0800
From:   Liu Xiang <liu.xiang6@....com.cn>
To:     viro@...iv.linux.org.uk
Cc:     linux-fsdevel@...r.kernel.org, linux-kernel@...r.kernel.org,
        liuxiang_1999@....com, Liu Xiang <liu.xiang6@....com.cn>
Subject: [PATCH v2] fs: buffer: fix fully_mapped reset in block_read_full_page()

Because get_block() might set the buffer mapped, fully_mapped reset 
should be done according to the result of buffer_mapped(bh) 
which check the buffer mapped attribute again after get_block().

Signed-off-by: Liu Xiang <liu.xiang6@....com.cn>
---

Changes in v2:
 change comment

 fs/buffer.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/buffer.c b/fs/buffer.c
index e450c55..987aadb 100644
--- a/fs/buffer.c
+++ b/fs/buffer.c
@@ -2243,7 +2243,6 @@ int block_read_full_page(struct page *page, get_block_t *get_block)
 		if (!buffer_mapped(bh)) {
 			int err = 0;
 
-			fully_mapped = 0;
 			if (iblock < lblock) {
 				WARN_ON(bh->b_size != blocksize);
 				err = get_block(inode, iblock, bh, 0);
@@ -2251,6 +2250,7 @@ int block_read_full_page(struct page *page, get_block_t *get_block)
 					SetPageError(page);
 			}
 			if (!buffer_mapped(bh)) {
+				fully_mapped = 0;
 				zero_user(page, i * blocksize, blocksize);
 				if (!err)
 					set_buffer_uptodate(bh);
-- 
1.9.1