On Tue, Jan 07, 2025 at 09:11:23PM +0800, Long Li wrote: > On Mon, Jan 06, 2025 at 11:52:20AM -0800, Darrick J. Wong wrote: > > On Tue, Dec 31, 2024 at 10:34:22AM +0800, Long Li wrote: > > > When mounting an xfs disk that incompat with metadir and has no realtime > > > subvolume, if CONFIG_XFS_RT is not enabled in the kernel, the mount will > > > fail. During superblock log recovery, since mp->m_sb.sb_rgcount is greater > > > than 0, updating the last rtag in-core is required, however, without > > > CONFIG_XFS_RT enabled, xfs_update_last_rtgroup_size() always returns > > > -EOPNOTSUPP, leading to mount failure. > > > > Didn't we fix the xfs_update_last_rtgroup_size stub to return 0? > > > > --D > > Indeed, when CONFIG_XFS_RT is not enabled, xfs_update_last_rtgroup_size() should > return 0, as returning an error is meaningless. > > 1) For kernels without CONFIG_XFS_RT, mounting an image with realtime subvolume will > fail at xfs_rtmount_init(). > > 2) For kernels without CONFIG_XFS_RT, mounting an image without realtime subvolume > should succeed. > > However, in the current scenario, should sb_rgcount be initialized to 0 ? it will > consistent with metadir feature is enabled. The xfs-documentation [1] describes > sb_rgcount as follows: > > "Count of realtime groups in the filesystem, if the XFS_SB_FEAT_RO_INCOMPAT_METADIR > feature is enabled. If no realtime subvolume exists, this value will be zero." > > [1] https://git.kernel.org/pub/scm/fs/xfs/xfs-documentation.git/tree/design/XFS_Filesystem_Structure/superblock.asciidoc Ah, I see your point finally -- if there's no realtime section, then there's no need to allocate any incore rtgroups, nor is there any point to set sb_rgcount==1. That said, I think the correct tags here are: Cc: <stable@xxxxxxxxxxxxxxx> # v6.13-rc1 Fixes: 96768e91511bfc ("xfs: define the format of rt groups") because 96768e91511bfc is the commit that actually added "to->sb_rgcount = 1;". Reviewed-by: "Darrick J. Wong" <djwong@xxxxxxxxxx> --D > Thanks, > Long Li > > > > > > Initializing sb_rgcount as 1 is incorrect in this scenario. If no > > > realtime subvolume exists, the value of sb_rgcount should be set > > > to zero. Fix it by initializing sb_rgcount based on the actual number > > > of realtime blocks. > > > > > > Fixes: 87fe4c34a383 ("xfs: create incore realtime group structures") > > > Signed-off-by: Long Li <leo.lilong@xxxxxxxxxx> > > > --- > > > fs/xfs/libxfs/xfs_sb.c | 2 +- > > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > > > diff --git a/fs/xfs/libxfs/xfs_sb.c b/fs/xfs/libxfs/xfs_sb.c > > > index 3b5623611eba..1ea28f04b75a 100644 > > > --- a/fs/xfs/libxfs/xfs_sb.c > > > +++ b/fs/xfs/libxfs/xfs_sb.c > > > @@ -830,7 +830,7 @@ __xfs_sb_from_disk( > > > to->sb_rsumino = NULLFSINO; > > > } else { > > > to->sb_metadirino = NULLFSINO; > > > - to->sb_rgcount = 1; > > > + to->sb_rgcount = to->sb_rblocks > 0 ? 1 : 0; > > > to->sb_rgextents = 0; > > > } > > > } > > > -- > > > 2.39.2 > > > > > > > > >
