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authorSteven Whitehouse <swhiteho@redhat.com>2009-09-28 10:30:49 +0100
committerSteven Whitehouse <swhiteho@redhat.com>2009-12-03 11:42:47 +0000
commitf55073ff1eaf99f6b3bc62134a456638bca043a3 (patch)
tree9637792f97494de2336f17a90a756e91c7d25527 /fs/gfs2/ops_fstype.c
parent7e71c55ee73988d0cb61045660b899eaac23bf8f (diff)
downloadconfigs-f55073ff1eaf99f6b3bc62134a456638bca043a3.tar.gz
GFS2: Fix -o meta mounts for subsequent mounts (i.e. all but the first one)
We have a long term plan to use the "-o meta" flag to GFS2 mounts to access the alternate root which is used to store metadata for a GFS2 filesystem. This will allow us to eventually remove support for the gfs2meta filesystem type (which is in any case just a "front end" to the gfs2 filesystem type with the meta/master root). Currently the "-o meta" option is only taken into account on the initial mount of the filesystem. Subsequent mounts of the same filesystem (i.e. on the same device) result in basically the same as bind mounting the root of the original mount. This patch changes that by using what is more or less a copy of get_sb_bdev() and extending it so that it will take into account the alternate root in all cases. The main difference is that we have to parse the mount options a bit earlier. We can then use them to select the appropriate root towards the end of the function. In addition this also fixes a bug where it was possible (but certainly not desirable) to set different ro/rw options for the meta root when mounted via the gfs2meta fs compared with the original mount. Signed-off-by: Steven Whitehouse <swhiteho@redhat.com> Cc: Alexander Viro <aviro@redhat.com>
Diffstat (limited to 'fs/gfs2/ops_fstype.c')
-rw-r--r--fs/gfs2/ops_fstype.c135
1 files changed, 118 insertions, 17 deletions
diff --git a/fs/gfs2/ops_fstype.c b/fs/gfs2/ops_fstype.c
index 52fb6c04898..e5ee06231ae 100644
--- a/fs/gfs2/ops_fstype.c
+++ b/fs/gfs2/ops_fstype.c
@@ -1114,7 +1114,7 @@ void gfs2_online_uevent(struct gfs2_sbd *sdp)
* Returns: errno
*/
-static int fill_super(struct super_block *sb, void *data, int silent)
+static int fill_super(struct super_block *sb, struct gfs2_args *args, int silent)
{
struct gfs2_sbd *sdp;
struct gfs2_holder mount_gh;
@@ -1125,17 +1125,7 @@ static int fill_super(struct super_block *sb, void *data, int silent)
printk(KERN_WARNING "GFS2: can't alloc struct gfs2_sbd\n");
return -ENOMEM;
}
-
- sdp->sd_args.ar_quota = GFS2_QUOTA_DEFAULT;
- sdp->sd_args.ar_data = GFS2_DATA_DEFAULT;
- sdp->sd_args.ar_commit = 60;
- sdp->sd_args.ar_errors = GFS2_ERRORS_DEFAULT;
-
- error = gfs2_mount_args(sdp, &sdp->sd_args, data);
- if (error) {
- printk(KERN_WARNING "GFS2: can't parse mount arguments\n");
- goto fail;
- }
+ sdp->sd_args = *args;
if (sdp->sd_args.ar_spectator) {
sb->s_flags |= MS_RDONLY;
@@ -1243,18 +1233,125 @@ fail:
return error;
}
-static int gfs2_get_sb(struct file_system_type *fs_type, int flags,
- const char *dev_name, void *data, struct vfsmount *mnt)
+static int set_gfs2_super(struct super_block *s, void *data)
{
- return get_sb_bdev(fs_type, flags, dev_name, data, fill_super, mnt);
+ s->s_bdev = data;
+ s->s_dev = s->s_bdev->bd_dev;
+
+ /*
+ * We set the bdi here to the queue backing, file systems can
+ * overwrite this in ->fill_super()
+ */
+ s->s_bdi = &bdev_get_queue(s->s_bdev)->backing_dev_info;
+ return 0;
}
-static int test_meta_super(struct super_block *s, void *ptr)
+static int test_gfs2_super(struct super_block *s, void *ptr)
{
struct block_device *bdev = ptr;
return (bdev == s->s_bdev);
}
+/**
+ * gfs2_get_sb - Get the GFS2 superblock
+ * @fs_type: The GFS2 filesystem type
+ * @flags: Mount flags
+ * @dev_name: The name of the device
+ * @data: The mount arguments
+ * @mnt: The vfsmnt for this mount
+ *
+ * Q. Why not use get_sb_bdev() ?
+ * A. We need to select one of two root directories to mount, independent
+ * of whether this is the initial, or subsequent, mount of this sb
+ *
+ * Returns: 0 or -ve on error
+ */
+
+static int gfs2_get_sb(struct file_system_type *fs_type, int flags,
+ const char *dev_name, void *data, struct vfsmount *mnt)
+{
+ struct block_device *bdev;
+ struct super_block *s;
+ fmode_t mode = FMODE_READ;
+ int error;
+ struct gfs2_args args;
+ struct gfs2_sbd *sdp;
+
+ if (!(flags & MS_RDONLY))
+ mode |= FMODE_WRITE;
+
+ bdev = open_bdev_exclusive(dev_name, mode, fs_type);
+ if (IS_ERR(bdev))
+ return PTR_ERR(bdev);
+
+ /*
+ * once the super is inserted into the list by sget, s_umount
+ * will protect the lockfs code from trying to start a snapshot
+ * while we are mounting
+ */
+ mutex_lock(&bdev->bd_fsfreeze_mutex);
+ if (bdev->bd_fsfreeze_count > 0) {
+ mutex_unlock(&bdev->bd_fsfreeze_mutex);
+ error = -EBUSY;
+ goto error_bdev;
+ }
+ s = sget(fs_type, test_gfs2_super, set_gfs2_super, bdev);
+ mutex_unlock(&bdev->bd_fsfreeze_mutex);
+ error = PTR_ERR(s);
+ if (IS_ERR(s))
+ goto error_bdev;
+
+ memset(&args, 0, sizeof(args));
+ args.ar_quota = GFS2_QUOTA_DEFAULT;
+ args.ar_data = GFS2_DATA_DEFAULT;
+ args.ar_commit = 60;
+ args.ar_errors = GFS2_ERRORS_DEFAULT;
+
+ error = gfs2_mount_args(&args, data);
+ if (error) {
+ printk(KERN_WARNING "GFS2: can't parse mount arguments\n");
+ if (s->s_root)
+ goto error_super;
+ deactivate_locked_super(s);
+ return error;
+ }
+
+ if (s->s_root) {
+ error = -EBUSY;
+ if ((flags ^ s->s_flags) & MS_RDONLY)
+ goto error_super;
+ close_bdev_exclusive(bdev, mode);
+ } else {
+ char b[BDEVNAME_SIZE];
+
+ s->s_flags = flags;
+ s->s_mode = mode;
+ strlcpy(s->s_id, bdevname(bdev, b), sizeof(s->s_id));
+ sb_set_blocksize(s, block_size(bdev));
+ error = fill_super(s, &args, flags & MS_SILENT ? 1 : 0);
+ if (error) {
+ deactivate_locked_super(s);
+ return error;
+ }
+ s->s_flags |= MS_ACTIVE;
+ bdev->bd_super = s;
+ }
+
+ sdp = s->s_fs_info;
+ mnt->mnt_sb = s;
+ if (args.ar_meta)
+ mnt->mnt_root = dget(sdp->sd_master_dir);
+ else
+ mnt->mnt_root = dget(sdp->sd_root_dir);
+ return 0;
+
+error_super:
+ deactivate_locked_super(s);
+error_bdev:
+ close_bdev_exclusive(bdev, mode);
+ return error;
+}
+
static int set_meta_super(struct super_block *s, void *ptr)
{
return -EINVAL;
@@ -1274,13 +1371,17 @@ static int gfs2_get_sb_meta(struct file_system_type *fs_type, int flags,
dev_name, error);
return error;
}
- s = sget(&gfs2_fs_type, test_meta_super, set_meta_super,
+ s = sget(&gfs2_fs_type, test_gfs2_super, set_meta_super,
path.dentry->d_inode->i_sb->s_bdev);
path_put(&path);
if (IS_ERR(s)) {
printk(KERN_WARNING "GFS2: gfs2 mount does not exist\n");
return PTR_ERR(s);
}
+ if ((flags ^ s->s_flags) & MS_RDONLY) {
+ deactivate_locked_super(s);
+ return -EBUSY;
+ }
sdp = s->s_fs_info;
mnt->mnt_sb = s;
mnt->mnt_root = dget(sdp->sd_master_dir);