[GFS2] Allow mounting of gfs2 and gfs2meta at the same time
This patch allows the simultaneous mounting of gfs2meta and gfs2
filesystems. A restriction however is that a gfs2meta fs may only be
mounted if its corresponding gfs2 filesystem is also mounted. Also, a
gfs2 filesystem cannot be unmounted before its gfs2meta filesystem.
Signed-off-by: Abhijith Das <adas@redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
diff --git a/fs/gfs2/ops_fstype.c b/fs/gfs2/ops_fstype.c
index c66067c..e5a91ea 100644
--- a/fs/gfs2/ops_fstype.c
+++ b/fs/gfs2/ops_fstype.c
@@ -15,6 +15,8 @@
#include <linux/vmalloc.h>
#include <linux/blkdev.h>
#include <linux/kthread.h>
+#include <linux/namei.h>
+#include <linux/mount.h>
#include <linux/gfs2_ondisk.h>
#include "gfs2.h"
@@ -813,7 +815,138 @@
static int gfs2_get_sb(struct file_system_type *fs_type, int flags,
const char *dev_name, void *data, struct vfsmount *mnt)
{
- return get_sb_bdev(fs_type, flags, dev_name, data, fill_super, mnt);
+ struct super_block *sb;
+ struct gfs2_sbd *sdp;
+ int error = get_sb_bdev(fs_type, flags, dev_name, data, fill_super, mnt);
+ if (error)
+ goto out;
+ sb = mnt->mnt_sb;
+ sdp = (struct gfs2_sbd*)sb->s_fs_info;
+ sdp->sd_gfs2mnt = mnt;
+out:
+ return error;
+}
+
+static int fill_super_meta(struct super_block *sb, struct super_block *new,
+ void *data, int silent)
+{
+ struct gfs2_sbd *sdp = sb->s_fs_info;
+ struct inode *inode;
+ int error = 0;
+
+ new->s_fs_info = sdp;
+ sdp->sd_vfs_meta = sb;
+
+ init_vfs(new, SDF_NOATIME);
+
+ /* Get the master inode */
+ inode = igrab(sdp->sd_master_dir);
+
+ new->s_root = d_alloc_root(inode);
+ if (!new->s_root) {
+ fs_err(sdp, "can't get root dentry\n");
+ error = -ENOMEM;
+ iput(inode);
+ }
+ new->s_root->d_op = &gfs2_dops;
+
+ return error;
+}
+static int set_bdev_super(struct super_block *s, void *data)
+{
+ s->s_bdev = data;
+ s->s_dev = s->s_bdev->bd_dev;
+ return 0;
+}
+
+static int test_bdev_super(struct super_block *s, void *data)
+{
+ return (void *)s->s_bdev == data;
+}
+
+static struct super_block* get_gfs2_sb(const char *dev_name)
+{
+ struct kstat stat;
+ struct nameidata nd;
+ struct file_system_type *fstype;
+ struct super_block *sb = NULL, *s;
+ struct list_head *l;
+ int error;
+
+ error = path_lookup(dev_name, LOOKUP_FOLLOW, &nd);
+ if (error) {
+ printk(KERN_WARNING "GFS2: path_lookup on %s returned error\n",
+ dev_name);
+ goto out;
+ }
+ error = vfs_getattr(nd.mnt, nd.dentry, &stat);
+
+ fstype = get_fs_type("gfs2");
+ list_for_each(l, &fstype->fs_supers) {
+ s = list_entry(l, struct super_block, s_instances);
+ if ((S_ISBLK(stat.mode) && s->s_dev == stat.rdev) ||
+ (S_ISDIR(stat.mode) && s == nd.dentry->d_inode->i_sb)) {
+ sb = s;
+ goto free_nd;
+ }
+ }
+
+ printk(KERN_WARNING "GFS2: Unrecognized block device or "
+ "mount point %s", dev_name);
+
+free_nd:
+ path_release(&nd);
+out:
+ return sb;
+}
+
+static int gfs2_get_sb_meta(struct file_system_type *fs_type, int flags,
+ const char *dev_name, void *data, struct vfsmount *mnt)
+{
+ int error = 0;
+ struct super_block *sb = NULL, *new;
+ struct gfs2_sbd *sdp;
+ char *gfs2mnt = NULL;
+
+ sb = get_gfs2_sb(dev_name);
+ if (!sb) {
+ printk(KERN_WARNING "GFS2: gfs2 mount does not exist\n");
+ error = -ENOENT;
+ goto error;
+ }
+ sdp = (struct gfs2_sbd*) sb->s_fs_info;
+ if (sdp->sd_vfs_meta) {
+ printk(KERN_WARNING "GFS2: gfs2meta mount already exists\n");
+ error = -EBUSY;
+ goto error;
+ }
+ mutex_lock(&sb->s_bdev->bd_mount_mutex);
+ new = sget(fs_type, test_bdev_super, set_bdev_super, sb->s_bdev);
+ mutex_unlock(&sb->s_bdev->bd_mount_mutex);
+ if (IS_ERR(new)) {
+ error = PTR_ERR(new);
+ goto error;
+ }
+ module_put(fs_type->owner);
+ new->s_flags = flags;
+ strlcpy(new->s_id, sb->s_id, sizeof(new->s_id));
+ sb_set_blocksize(new, sb->s_blocksize);
+ error = fill_super_meta(sb, new, data, flags & MS_SILENT ? 1 : 0);
+ if (error) {
+ up_write(&new->s_umount);
+ deactivate_super(new);
+ goto error;
+ }
+
+ new->s_flags |= MS_ACTIVE;
+
+ /* Grab a reference to the gfs2 mount point */
+ atomic_inc(&sdp->sd_gfs2mnt->mnt_count);
+ return simple_set_mnt(mnt, new);
+error:
+ if (gfs2mnt)
+ kfree(gfs2mnt);
+ return error;
}
static void gfs2_kill_sb(struct super_block *sb)
@@ -821,6 +954,14 @@
kill_block_super(sb);
}
+static void gfs2_kill_sb_meta(struct super_block *sb)
+{
+ struct gfs2_sbd *sdp = sb->s_fs_info;
+ generic_shutdown_super(sb);
+ sdp->sd_vfs_meta = NULL;
+ atomic_dec(&sdp->sd_gfs2mnt->mnt_count);
+}
+
struct file_system_type gfs2_fs_type = {
.name = "gfs2",
.fs_flags = FS_REQUIRES_DEV,
@@ -832,8 +973,8 @@
struct file_system_type gfs2meta_fs_type = {
.name = "gfs2meta",
.fs_flags = FS_REQUIRES_DEV,
- .get_sb = gfs2_get_sb,
- .kill_sb = gfs2_kill_sb,
+ .get_sb = gfs2_get_sb_meta,
+ .kill_sb = gfs2_kill_sb_meta,
.owner = THIS_MODULE,
};