| Message ID | 20240304155013.115334-2-aalbersh@redhat.com (mailing list archive) |
|---|---|
| State | Superseded, archived |
| Headers | show |
| Series | xfs: allow cross-linking special files without project quota | expand |
On Mon, Mar 04, 2024 at 04:50:14PM +0100, Andrey Albershteyn wrote: > 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). Reasonable. > Signed-off-by: Andrey Albershteyn <aalbersh@redhat.com> > --- > fs/xfs/xfs_inode.c | 13 +++++++++++++ > 1 file changed, 13 insertions(+) > > diff --git a/fs/xfs/xfs_inode.c b/fs/xfs/xfs_inode.c > index 5ca561634164..641270f4d794 100644 > --- a/fs/xfs/xfs_inode.c > +++ b/fs/xfs/xfs_inode.c > @@ -1232,11 +1232,24 @@ xfs_link( > * the tree quota mechanism could be circumvented. > */ > if (unlikely((tdp->i_diflags & XFS_DIFLAG_PROJINHERIT) && > + !special_file(VFS_I(sip)->i_mode) && > tdp->i_projid != sip->i_projid)) { > error = -EXDEV; > goto error_return; > } > > + /* > + * Don't allow cross-linking of special files. However, allow > + * cross-linking if original file doesn't have any project. > + */ The comment should explain why the code exists, not document what the code does. > + if (unlikely((tdp->i_diflags & XFS_DIFLAG_PROJINHERIT) && > + special_file(VFS_I(sip)->i_mode) && > + sip->i_projid != 0 && > + tdp->i_projid != sip->i_projid)) { > + error = -EXDEV; > + goto error_return; > + } I think this would be better written as: /* * If we are using project inheritance, we only allow hard link * creation in our tree when the project IDs are the same; else * the tree quota mechanism could be circumvented. */ if ((tdp->i_diflags & XFS_DIFLAG_PROJINHERIT) && tdp->i_projid != sip->i_projid) { /* * 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; } } Cheers, Dave.
diff --git a/fs/xfs/xfs_inode.c b/fs/xfs/xfs_inode.c index 5ca561634164..641270f4d794 100644 --- a/fs/xfs/xfs_inode.c +++ b/fs/xfs/xfs_inode.c @@ -1232,11 +1232,24 @@ xfs_link( * the tree quota mechanism could be circumvented. */ if (unlikely((tdp->i_diflags & XFS_DIFLAG_PROJINHERIT) && + !special_file(VFS_I(sip)->i_mode) && tdp->i_projid != sip->i_projid)) { error = -EXDEV; goto error_return; } + /* + * Don't allow cross-linking of special files. However, allow + * cross-linking if original file doesn't have any project. + */ + if (unlikely((tdp->i_diflags & XFS_DIFLAG_PROJINHERIT) && + special_file(VFS_I(sip)->i_mode) && + sip->i_projid != 0 && + tdp->i_projid != sip->i_projid)) { + error = -EXDEV; + goto error_return; + } + if (!resblks) { error = xfs_dir_canenter(tp, tdp, target_name); if (error)