From e23d7e82b707d1d0a627e334fb46370e4f772c11 Mon Sep 17 00:00:00 2001 From: Andrey Albershteyn Date: Thu, 14 Mar 2024 18:07:02 +0100 Subject: xfs: allow cross-linking special files without project quota There's an issue that if special files is created before quota project is enabled, then it's not possible to link this file. This works fine for normal files. This happens because xfs_quota skips special files (no ioctls to set necessary flags). The check for having the same project ID for source and destination then fails as source file doesn't have any ID. mkfs.xfs -f /dev/sda mount -o prjquota /dev/sda /mnt/test mkdir /mnt/test/foo mkfifo /mnt/test/foo/fifo1 xfs_quota -xc "project -sp /mnt/test/foo 9" /mnt/test > Setting up project 9 (path /mnt/test/foo)... > xfs_quota: skipping special file /mnt/test/foo/fifo1 > Processed 1 (/etc/projects and cmdline) paths for project 9 with recursion depth infinite (-1). ln /mnt/test/foo/fifo1 /mnt/test/foo/fifo1_link > ln: failed to create hard link '/mnt/test/testdir/fifo1_link' => '/mnt/test/testdir/fifo1': Invalid cross-device link mkfifo /mnt/test/foo/fifo2 ln /mnt/test/foo/fifo2 /mnt/test/foo/fifo2_link Fix this by allowing linking of special files to the project quota if special files doesn't have any ID set (ID = 0). Signed-off-by: Andrey Albershteyn Reviewed-by: "Darrick J. Wong" Signed-off-by: Chandan Babu R --- fs/xfs/xfs_inode.c | 15 +++++++++++++-- 1 file changed, 13 insertions(+), 2 deletions(-) diff --git a/fs/xfs/xfs_inode.c b/fs/xfs/xfs_inode.c index ea48774f6b76..d55b42b2480d 100644 --- a/fs/xfs/xfs_inode.c +++ b/fs/xfs/xfs_inode.c @@ -1301,8 +1301,19 @@ xfs_link( */ if (unlikely((tdp->i_diflags & XFS_DIFLAG_PROJINHERIT) && tdp->i_projid != sip->i_projid)) { - error = -EXDEV; - goto error_return; + /* + * Project quota setup skips special files which can + * leave inodes in a PROJINHERIT directory without a + * project ID set. We need to allow links to be made + * to these "project-less" inodes because userspace + * expects them to succeed after project ID setup, + * but everything else should be rejected. + */ + if (!special_file(VFS_I(sip)->i_mode) || + sip->i_projid != 0) { + error = -EXDEV; + goto error_return; + } } if (!resblks) { -- cgit v1.2.3