Re: Bug/regression: Read-only mount not read-only

[Austin S Hemmelgarn]

On 2015-12-02 18:51, Hugo Mills wrote:

On Thu, Dec 03, 2015 at 07:40:08AM +0800, Qu Wenruo wrote:

On 12/03/2015 06:48 AM, Eric Sandeen wrote:

On 12/2/15 11:48 AM, Austin S Hemmelgarn wrote:

On a side note, do either XFS or ext4 support removing the norecovery
option from the mount flags through mount -o remount?  Even if they
don't, that might be a nice feature to have in BTRFS if we can safely
support it.

It's not remountable today on xfs:

         /* ro -> rw */
         if ((mp->m_flags & XFS_MOUNT_RDONLY) && !(*flags & MS_RDONLY)) {
                 if (mp->m_flags & XFS_MOUNT_NORECOVERY) {
                         xfs_warn(mp,
                 "ro->rw transition prohibited on norecovery mount");
                         return -EINVAL;
                 }

not sure about ext4.

-Eric

Not remountable is very good to implement it.
Makes things super easy to do.

Or we will need to add log replay for remount time.

I'd like to implement it first for non-remountable case as a try.
And for the option name, I prefer something like "notreereplay", but
I don't consider it the best one yet....

    Thinking out loud...

no-log-replay, no-log, hard-ro, ro-log,
really-read-only-i-mean-it-this-time-honest-guvnor

Delete hyphens at your pleasure.

Personally, I think no-log-replay (with or without hyphens) is the most concise option name. With something like this, it should be as clear as possible what is being done.

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