On Sun, Oct 07, 2018 at 12:08:11AM +0200, Adam Borowski wrote: > Needed by userspace programs that call fstatfs(). > > It'd be natural to publish XFS_SB_MAGIC in uapi, but while these two have > identical values, they have different semantic meaning: one is an enum > cookie meant for statfs, the other a signature of the on-disk format. > > Signed-off-by: Adam Borowski <kilobyte@xxxxxxxxxx> > --- > > > include/uapi/linux/magic.h would get: > > > > > > #define XFS_STATFS_MAGIC 0x58465342 /* 'XFSB' */ > > > > $ man statfs |grep 0x5846 > > XFS_SUPER_MAGIC 0x58465342 > > Indeed, not only it is documented this way, but almost every other > filesystem has the define named FOO_SUPER_MAGIC. Thus, inventing something > else doesn't seem to be a good idea to me. > > On the other hand, this might be considered bikeshedding, and you're the > maintainer of this particular shed... > > > fs/xfs/xfs_super.c | 5 +++-- > include/uapi/linux/magic.h | 1 + > 2 files changed, 4 insertions(+), 2 deletions(-) > > diff --git a/fs/xfs/xfs_super.c b/fs/xfs/xfs_super.c > index 207ee302b1bb..90b08051a4f3 100644 > --- a/fs/xfs/xfs_super.c > +++ b/fs/xfs/xfs_super.c > @@ -43,6 +43,7 @@ > #include <linux/dax.h> > #include <linux/init.h> > #include <linux/slab.h> > +#include <linux/magic.h> > #include <linux/mount.h> > #include <linux/mempool.h> > #include <linux/writeback.h> > @@ -1097,7 +1098,7 @@ xfs_fs_statfs( > xfs_extlen_t lsize; > int64_t ffree; > > - statp->f_type = XFS_SB_MAGIC; > + statp->f_type = XFS_SUPER_MAGIC; > statp->f_namelen = MAXNAMELEN - 1; > > id = huge_encode_dev(mp->m_ddev_targp->bt_dev); > @@ -1650,7 +1651,7 @@ xfs_fs_fill_super( > * we must configure the block size in the superblock before we run the > * full mount process as the mount process can lookup and cache inodes. > */ > - sb->s_magic = XFS_SB_MAGIC; > + sb->s_magic = XFS_SUPER_MAGIC; > sb->s_blocksize = mp->m_sb.sb_blocksize; > sb->s_blocksize_bits = ffs(sb->s_blocksize) - 1; > sb->s_maxbytes = xfs_max_file_offset(sb->s_blocksize_bits); > diff --git a/include/uapi/linux/magic.h b/include/uapi/linux/magic.h > index 1a6fee974116..96c24478d8ce 100644 > --- a/include/uapi/linux/magic.h > +++ b/include/uapi/linux/magic.h > @@ -29,6 +29,7 @@ > #define HPFS_SUPER_MAGIC 0xf995e849 > #define ISOFS_SUPER_MAGIC 0x9660 > #define JFFS2_SUPER_MAGIC 0x72b6 > +#define XFS_SUPER_MAGIC 0x58465342 /* "XFSB" */ Looks ok to me... Reviewed-by: Darrick J. Wong <darrick.wong@xxxxxxxxxx> --D > #define PSTOREFS_MAGIC 0x6165676C > #define EFIVARFS_MAGIC 0xde5e81e4 > #define HOSTFS_SUPER_MAGIC 0x00c0ffee > -- > 2.19.1 >
