Re: [PATCH v2] f2fs: fix deadlock in i_xattr_sem and inode page lock and fix the original issue
From: Jaegeuk Kim
Date: Wed Jun 28 2023 - 04:11:55 EST
Thread #1:
[122554.641906][ T92] f2fs_getxattr+0xd4/0x5fc
-> waiting for f2fs_down_read(&F2FS_I(inode)->i_xattr_sem);
[122554.641927][ T92] __f2fs_get_acl+0x50/0x284
[122554.641948][ T92] f2fs_init_acl+0x84/0x54c
[122554.641969][ T92] f2fs_init_inode_metadata+0x460/0x5f0
[122554.641990][ T92] f2fs_add_inline_entry+0x11c/0x350
-> Locked dir->inode_page by f2fs_get_node_page()
[122554.642009][ T92] f2fs_do_add_link+0x100/0x1e4
[122554.642025][ T92] f2fs_create+0xf4/0x22c
[122554.642047][ T92] vfs_create+0x130/0x1f4
Thread #2:
[123996.386358][ T92] __get_node_page+0x8c/0x504
-> waiting for dir->inode_page lock
[123996.386383][ T92] read_all_xattrs+0x11c/0x1f4
[123996.386405][ T92] __f2fs_setxattr+0xcc/0x528
[123996.386424][ T92] f2fs_setxattr+0x158/0x1f4
-> f2fs_down_write(&F2FS_I(inode)->i_xattr_sem);
[123996.386443][ T92] __f2fs_set_acl+0x328/0x430
[123996.386618][ T92] f2fs_set_acl+0x38/0x50
[123996.386642][ T92] posix_acl_chmod+0xc8/0x1c8
[123996.386669][ T92] f2fs_setattr+0x5e0/0x6bc
[123996.386689][ T92] notify_change+0x4d8/0x580
[123996.386717][ T92] chmod_common+0xd8/0x184
[123996.386748][ T92] do_fchmodat+0x60/0x124
[123996.386766][ T92] __arm64_sys_fchmodat+0x28/0x3c
Fixes: 27161f13e3c3 "f2fs: avoid race in between read xattr & write xattr"
Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Jaegeuk Kim <jaegeuk@xxxxxxxxxx>
---
fs/f2fs/dir.c | 9 ++++++++-
fs/f2fs/xattr.c | 6 ++++--
2 files changed, 12 insertions(+), 3 deletions(-)
diff --git a/fs/f2fs/dir.c b/fs/f2fs/dir.c
index 887e55988450..d635c58cf5a3 100644
--- a/fs/f2fs/dir.c
+++ b/fs/f2fs/dir.c
@@ -775,8 +775,15 @@ int f2fs_add_dentry(struct inode *dir, const struct f2fs_filename *fname,
{
int err = -EAGAIN;
- if (f2fs_has_inline_dentry(dir))
+ if (f2fs_has_inline_dentry(dir)) {
+ /*
+ * Should get i_xattr_sem to keep the lock order:
+ * i_xattr_sem -> inode_page lock used by f2fs_setxattr.
+ */
+ f2fs_down_read(&F2FS_I(dir)->i_xattr_sem);
err = f2fs_add_inline_entry(dir, fname, inode, ino, mode);
+ f2fs_up_read(&F2FS_I(dir)->i_xattr_sem);
+ }
if (err == -EAGAIN)
err = f2fs_add_regular_entry(dir, fname, inode, ino, mode);
diff --git a/fs/f2fs/xattr.c b/fs/f2fs/xattr.c
index 213805d3592c..476b186b90a6 100644
--- a/fs/f2fs/xattr.c
+++ b/fs/f2fs/xattr.c
@@ -528,10 +528,12 @@ int f2fs_getxattr(struct inode *inode, int index, const char *name,
if (len > F2FS_NAME_LEN)
return -ERANGE;
- f2fs_down_read(&F2FS_I(inode)->i_xattr_sem);
+ if (!ipage)
+ f2fs_down_read(&F2FS_I(inode)->i_xattr_sem);
error = lookup_all_xattrs(inode, ipage, index, len, name,
&entry, &base_addr, &base_size, &is_inline);
- f2fs_up_read(&F2FS_I(inode)->i_xattr_sem);
+ if (!ipage)
+ f2fs_up_read(&F2FS_I(inode)->i_xattr_sem);
if (error)
return error;
--
2.41.0.162.gfafddb0af9-goog