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Subject[PATCH 4.19 007/187] f2fs: fix to adapt small inline xattr space in __find_inline_xattr()
Date
4.19-stable review patch.  If anyone has any objections, please let me know.

------------------

[ Upstream commit 2c28aba8b2e2a51749fa66e01b68e1cd5b53e022 ]

With below testcase, we will fail to find existed xattr entry:

1. mkfs.f2fs -O extra_attr -O flexible_inline_xattr /dev/zram0
2. mount -t f2fs -o inline_xattr_size=1 /dev/zram0 /mnt/f2fs/
3. touch /mnt/f2fs/file
4. setfattr -n "user.name" -v 0 /mnt/f2fs/file
5. getfattr -n "user.name" /mnt/f2fs/file

/mnt/f2fs/file: user.name: No such attribute

The reason is for inode which has very small inline xattr size,
__find_inline_xattr() will fail to traverse any entry due to first
entry may not be loaded from xattr node yet, later, we may skip to
check entire xattr datas in __find_xattr(), result in such wrong
condition.

This patch adds condition to check such case to avoid this issue.

Signed-off-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
fs/f2fs/xattr.c | 13 ++++++++++---
1 file changed, 10 insertions(+), 3 deletions(-)

diff --git a/fs/f2fs/xattr.c b/fs/f2fs/xattr.c
index 087e53a2d96c..409a637f7a92 100644
--- a/fs/f2fs/xattr.c
+++ b/fs/f2fs/xattr.c
@@ -227,11 +227,11 @@ static struct f2fs_xattr_entry *__find_inline_xattr(struct inode *inode,
{
struct f2fs_xattr_entry *entry;
unsigned int inline_size = inline_xattr_size(inode);
+ void *max_addr = base_addr + inline_size;

list_for_each_xattr(entry, base_addr) {
- if ((void *)entry + sizeof(__u32) > base_addr + inline_size ||
- (void *)XATTR_NEXT_ENTRY(entry) + sizeof(__u32) >
- base_addr + inline_size) {
+ if ((void *)entry + sizeof(__u32) > max_addr ||
+ (void *)XATTR_NEXT_ENTRY(entry) > max_addr) {
*last_addr = entry;
return NULL;
}
@@ -242,6 +242,13 @@ static struct f2fs_xattr_entry *__find_inline_xattr(struct inode *inode,
if (!memcmp(entry->e_name, name, len))
break;
}
+
+ /* inline xattr header or entry across max inline xattr size */
+ if (IS_XATTR_LAST_ENTRY(entry) &&
+ (void *)entry + sizeof(__u32) > max_addr) {
+ *last_addr = entry;
+ return NULL;
+ }
return entry;
}

--
2.19.1


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