On 06/28, Chao Yu wrote:
> On 2023/6/28 16:08, Jaegeuk Kim wrote:
> > 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
>
> Back to the race condition, my question is why we can chmod on inode before
> it has been created?
This is touching the directory.
>
> Thanks,
>
> >
> > 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;
