| Message ID | 1371569344-2978-1-git-send-email-harald@redhat.com (mailing list archive) |
|---|---|
| State | Superseded, archived |
| Headers | show |
On 06/18/2013 05:29 PM, harald@redhat.com wrote: > From: Harald Hoyer <harald@redhat.com> > > Given the following /etc/fstab entries: > > /dev/sda3 /mnt/foo btrfs subvol=foo,ro 0 > /dev/sda3 /mnt/bar btrfs subvol=bar,rw 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 /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(+) > > diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c > index f0857e0..80ed3e2 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"; > @@ -1036,6 +1038,26 @@ 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); > > Any comments? -- 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 09/02/2013 12:55 PM, Harald Hoyer wrote: > On 06/18/2013 05:29 PM, harald@redhat.com wrote: >> From: Harald Hoyer <harald@redhat.com> >> >> Given the following /etc/fstab entries: >> >> /dev/sda3 /mnt/foo btrfs subvol=foo,ro 0 >> /dev/sda3 /mnt/bar btrfs subvol=bar,rw 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 /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(+) >> >> diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c >> index f0857e0..80ed3e2 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"; >> @@ -1036,6 +1038,26 @@ 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); >> >> > > Any comments? > Not even a "no, we don't want that" ? -- 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 Sat, Sep 14, 2013 at 01:26:22PM +0200, Harald Hoyer wrote: > > Any comments? > Not even a "no, we don't want that" ? Please resend. david -- 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 11/18/2013 11:53 AM, David Sterba wrote: > On Sat, Sep 14, 2013 at 01:26:22PM +0200, Harald Hoyer wrote: >>> Any comments? >> Not even a "no, we don't want that" ? > > Please resend. > > david > done -- 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 f0857e0..80ed3e2 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"; @@ -1036,6 +1038,26 @@ 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 /dev/sda3 /mnt/bar btrfs subvol=bar,rw 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 /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(+)