| Message ID | 1384857365-7719-1-git-send-email-harald@redhat.com (mailing list archive) |
|---|---|
| State | Superseded, archived |
| Headers | show |
Quoting harald@redhat.com (2013-11-19 05:36:05) > From: Harald Hoyer <harald@redhat.com> > [ create new vfsmounts with different states ] Thanks for resending Harald. I'll give this a shot and see if I can find any problems with it. -chris -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Tue, Nov 19, 2013 at 09:35:32AM -0500, Chris Mason wrote: > Quoting harald@redhat.com (2013-11-19 05:36:05) > > From: Harald Hoyer <harald@redhat.com> > > > [ create new vfsmounts with different states ] > > Thanks for resending Harald. I'll give this a shot and see if I can > find any problems with it. Is this patch queued for 3.15? Thanks. -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c index 2d8ac1b..cd55f02 100644 --- a/fs/btrfs/super.c +++ b/fs/btrfs/super.c @@ -64,6 +64,8 @@ static const struct super_operations btrfs_super_ops; static struct file_system_type btrfs_fs_type; +static int btrfs_remount(struct super_block *sb, int *flags, char *data); + static const char *btrfs_decode_error(int errno) { char *errstr = "unknown"; @@ -1106,6 +1108,26 @@ static struct dentry *mount_subvol(const char *subvol_name, int flags, mnt = vfs_kern_mount(&btrfs_fs_type, flags, device_name, newargs); kfree(newargs); + + if (PTR_RET(mnt) == -EBUSY) { + if (flags & MS_RDONLY) { + mnt = vfs_kern_mount(&btrfs_fs_type, flags & ~MS_RDONLY, device_name, + newargs); + } else { + int r; + mnt = vfs_kern_mount(&btrfs_fs_type, flags | MS_RDONLY, device_name, + newargs); + if (IS_ERR(mnt)) + return ERR_CAST(mnt); + + r = btrfs_remount(mnt->mnt_sb, &flags, NULL); + if (r < 0) { + /* FIXME: release vfsmount mnt ??*/ + return ERR_PTR(r); + } + } + } + if (IS_ERR(mnt)) return ERR_CAST(mnt);
From: Harald Hoyer <harald@redhat.com> Given the following /etc/fstab entries: /dev/sda3 /mnt/foo btrfs subvol=foo,ro 0 0 /dev/sda3 /mnt/bar btrfs subvol=bar,rw 0 0 you can't issue: $ mount /mnt/foo $ mount /mnt/bar You would have to do: $ mount /mnt/foo $ mount -o remount,rw /mnt/foo $ mount --bind -o remount,ro /mnt/foo $ mount /mnt/bar or $ mount /mnt/bar $ mount --rw /mnt/foo $ mount --bind -o remount,ro /mnt/foo With this patch you can do $ mount /mnt/foo $ mount /mnt/bar $ cat /proc/self/mountinfo 49 33 0:41 /foo /mnt/foo ro,relatime shared:36 - btrfs /dev/sda3 rw,ssd,space_cache 87 33 0:41 /bar /mnt/bar rw,relatime shared:74 - btrfs /dev/sda3 rw,ssd,space_cache --- fs/btrfs/super.c | 22 ++++++++++++++++++++++ 1 file changed, 22 insertions(+)