| Message ID | 20210305120508.298465-1-yi.zhang@huawei.com |
|---|---|
| State | Awaiting Upstream |
| Headers | show |
| Series | ext4: do not try to set xattr into ea_inode if value is empty | expand |
On Fri, Mar 05, 2021 at 08:05:08PM +0800, zhangyi (F) wrote: > Syzbot report a warning that ext4 may create an empty ea_inode if set > an empty extent attribute to a file on the file system which is no free > blocks left. I'll apply this, but can you tell us which syzbot warning this addresses so we can mark the commit appropriately? Many thanks!! - Ted
On Thu, Mar 11, 2021 at 10:47:40AM -0500, Theodore Ts'o wrote: > On Fri, Mar 05, 2021 at 08:05:08PM +0800, zhangyi (F) wrote: > > Syzbot report a warning that ext4 may create an empty ea_inode if set > > an empty extent attribute to a file on the file system which is no free > > blocks left. > > I'll apply this, but can you tell us which syzbot warning this > addresses so we can mark the commit appropriately? Never mind, I missed the Reported-by: which identified the syzbot report. - Ted
diff --git a/fs/ext4/xattr.c b/fs/ext4/xattr.c index 372208500f4e..6aef74f7c9ee 100644 --- a/fs/ext4/xattr.c +++ b/fs/ext4/xattr.c @@ -2400,7 +2400,7 @@ ext4_xattr_set_handle(handle_t *handle, struct inode *inode, int name_index, * external inode if possible. */ if (ext4_has_feature_ea_inode(inode->i_sb) && - !i.in_inode) { + i.value_len && !i.in_inode) { i.in_inode = 1; goto retry_inode; }
Syzbot report a warning that ext4 may create an empty ea_inode if set an empty extent attribute to a file on the file system which is no free blocks left. WARNING: CPU: 6 PID: 10667 at fs/ext4/xattr.c:1640 ext4_xattr_set_entry+0x10f8/0x1114 fs/ext4/xattr.c:1640 ... Call trace: ext4_xattr_set_entry+0x10f8/0x1114 fs/ext4/xattr.c:1640 ext4_xattr_block_set+0x1d0/0x1b1c fs/ext4/xattr.c:1942 ext4_xattr_set_handle+0x8a0/0xf1c fs/ext4/xattr.c:2390 ext4_xattr_set+0x120/0x1f0 fs/ext4/xattr.c:2491 ext4_xattr_trusted_set+0x48/0x5c fs/ext4/xattr_trusted.c:37 __vfs_setxattr+0x208/0x23c fs/xattr.c:177 ... Now, ext4 try to store extent attribute into an external inode if ext4_xattr_block_set() return -ENOSPC, but for the case of store an empty extent attribute, store the extent entry into the extent attribute block is enough. A simple reproduce below. fallocate test.img -l 1M mkfs.ext4 -F -b 2048 -O ea_inode test.img mount test.img /mnt dd if=/dev/zero of=/mnt/foo bs=2048 count=500 setfattr -n "user.test" /mnt/foo Reported-by: syzbot+98b881fdd8ebf45ab4ae@syzkaller.appspotmail.com Signed-off-by: zhangyi (F) <yi.zhang@huawei.com> --- fs/ext4/xattr.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)