linux-ext4 - [PATCH] ext2: fix improper assignment for e_value

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Date:   Wed,  3 Jun 2020 16:44:29 +0800
From:   Chengguang Xu <cgxu519@...ernel.net>
To:     jack@...e.com
Cc:     linux-ext4@...r.kernel.org, Chengguang Xu <cgxu519@...ernel.net>
Subject: [PATCH] ext2: fix improper assignment for e_value_offs

In the process of changing value for existing EA,
there is an improper assignment of e_value_offs(setting to 0),
because it will be reset to incorrect value in the following
loop(shifting EA values before target). Delayed assignment
can avoid this issue.

Signed-off-by: Chengguang Xu <cgxu519@...ernel.net>
---
 fs/ext2/xattr.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/fs/ext2/xattr.c b/fs/ext2/xattr.c
index 943cc469f42f..c802ea682e7f 100644
--- a/fs/ext2/xattr.c
+++ b/fs/ext2/xattr.c
@@ -588,7 +588,6 @@ ext2_xattr_set(struct inode *inode, int name_index, const char *name,
 			/* Remove the old value. */
 			memmove(first_val + size, first_val, val - first_val);
 			memset(first_val, 0, size);
-			here->e_value_offs = 0;
 			min_offs += size;
 
 			/* Adjust all value offsets. */
@@ -600,6 +599,8 @@ ext2_xattr_set(struct inode *inode, int name_index, const char *name,
 						cpu_to_le16(o + size);
 				last = EXT2_XATTR_NEXT(last);
 			}
+
+			here->e_value_offs = 0;
 		}
 		if (value == NULL) {
 			/* Remove the old name. */
-- 
2.20.1