Re: [PATCH] btrfs: allow mounting btrfs subvolumes with different ro/rw options
On Tue, Nov 19, 2013 at 09:35:32AM -0500, Chris Mason wrote: Quoting har...@redhat.com (2013-11-19 05:36:05) From: Harald Hoyer har...@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 majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: [PATCH] btrfs: allow mounting btrfs subvolumes with different ro/rw options
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 majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: [PATCH] btrfs: allow mounting btrfs subvolumes with different ro/rw options
On 09/02/2013 12:55 PM, Harald Hoyer wrote:
On 06/18/2013 05:29 PM, har...@redhat.com wrote:
From: Harald Hoyer har...@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 ?
--
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Re: [PATCH] btrfs: allow mounting btrfs subvolumes with different ro/rw options
On 06/18/2013 05:29 PM, har...@redhat.com wrote:
From: Harald Hoyer har...@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?
--
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