From 53cf50e0816a89749b3ea4d51d5d9c9605bcc3e8 Mon Sep 17 00:00:00 2001 From: Brian Behlendorf Date: Mon, 7 Mar 2011 16:06:22 -0800 Subject: [PATCH] Set stat->st_dev and statfs->f_fsid Filesystems like ZFS must use what the kernel calls an anonymous super block. Basically, this is just a filesystem which is not backed by a single block device. Normally this block device's dev_t is stored in the super block. For anonymous super blocks a unique reserved dev_t is assigned as part of get_sb(). This sb->s_dev must then be set in the returned stat structures as stat->st_dev. This allows userspace utilities to easily detect the boundries of a specific filesystem. Tools such as 'du' depend on this for proper accounting. Additionally, under OpenSolaris the statfs->f_fsid is set to the device id. To preserve consistency with OpenSolaris we also set the fsid to the device id. Other Linux filesystem (ext) set the fsid to a unique value determined by the filesystems uuid. This value is unique but maintains no relationship to the device id. This may be desirable when exporting NFS filesystem because it minimizes to chance of a client observing the same fsid from two different servers. Closes #140 --- module/zfs/zfs_vfsops.c | 2 +- module/zfs/zfs_vnops.c | 2 +- module/zfs/zpl_inode.c | 2 +- 3 files changed, 3 insertions(+), 3 deletions(-) diff --git a/module/zfs/zfs_vfsops.c b/module/zfs/zfs_vfsops.c index 028638d5c..ea7e9cec9 100644 --- a/module/zfs/zfs_vfsops.c +++ b/module/zfs/zfs_vfsops.c @@ -1029,7 +1029,7 @@ zfs_statvfs(struct dentry *dentry, struct kstatfs *statp) */ statp->f_ffree = MIN(availobjs, statp->f_bfree); statp->f_files = statp->f_ffree + usedobjs; - statp->f_fsid.val[0] = 0; /* XXX: Map up some unique ID */ + statp->f_fsid.val[0] = dentry->d_sb->s_dev; statp->f_fsid.val[1] = 0; statp->f_type = ZFS_SUPER_MAGIC; statp->f_namelen = ZFS_MAXNAMELEN; diff --git a/module/zfs/zfs_vnops.c b/module/zfs/zfs_vnops.c index 7e8fd92b8..29ddaf0b7 100644 --- a/module/zfs/zfs_vnops.c +++ b/module/zfs/zfs_vnops.c @@ -2084,7 +2084,7 @@ zfs_getattr(struct inode *ip, vattr_t *vap, int flags, cred_t *cr) mutex_enter(&zp->z_lock); vap->va_type = vn_mode_to_vtype(zp->z_mode); vap->va_mode = zp->z_mode; - vap->va_fsid = 0; + vap->va_fsid = ZTOI(zp)->i_sb->s_dev; vap->va_nodeid = zp->z_id; if ((zp->z_id == zsb->z_root) && zfs_show_ctldir(zp)) links = zp->z_links + 1; diff --git a/module/zfs/zpl_inode.c b/module/zfs/zpl_inode.c index b7227675b..c4ff14fbb 100644 --- a/module/zfs/zpl_inode.c +++ b/module/zfs/zpl_inode.c @@ -184,7 +184,7 @@ zpl_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *stat) goto out; stat->ino = ip->i_ino; - stat->dev = 0; + stat->dev = ip->i_sb->s_dev; stat->mode = vap->va_mode; stat->nlink = vap->va_nlink; stat->uid = vap->va_uid;