On Monday 07 Dec 2015 10:27:05 Eric Sandeen wrote: > On 12/7/15 12:06 AM, Qu Wenruo wrote: > > Introduce a new mount option "nologreplay" to co-operate with "ro" mount > > option to get real readonly mount, like "norecovery" in ext* and xfs. > > > > Since the new parse_options() need to check new flags at remount time, > > so add a new parameter for parse_options(). > > > > Signed-off-by: Qu Wenruo <quwen...@cn.fujitsu.com> > > --- > > > > Documentation/filesystems/btrfs.txt | 5 +++++ > > fs/btrfs/ctree.h | 4 +++- > > fs/btrfs/disk-io.c | 7 ++++--- > > fs/btrfs/super.c | 20 +++++++++++++++++--- > > 4 files changed, 29 insertions(+), 7 deletions(-) > > > > diff --git a/Documentation/filesystems/btrfs.txt > > b/Documentation/filesystems/btrfs.txt index c772b47..ac4ed68 100644 > > --- a/Documentation/filesystems/btrfs.txt > > +++ b/Documentation/filesystems/btrfs.txt > > @@ -168,6 +168,11 @@ Options with (*) are default options and will not > > show in the mount options.> > > notreelog > > > > Enable/disable the tree logging used for fsync and O_SYNC writes. > > > > + nologreplay > > + Disable the log tree replay at mount time for real read-only mount. > > + Must be use with "ro" mount option and can't be disabled by mount > > + option. > > This documentation is not clear to me - "can't be disabled by mount option?" > > I think you mean to talk about remount here? Perhaps something like: > > "... Must be used with 'ro' mount option. A filesystem mounted with the > 'nologreplay' option cannot transition to a read-write mount via > remount,rw - the filesystem must be unmounted and remounted if read-write > access is desired." > Eric, I had assumed the same logic with respect to the transition from 'ro' to 'rw' via remount. But when doing so, btrfs_remount() flags an error only when a valid 'tree log' tree is present in the filesystem i.e. btrfs_super_block->log_root has a non-zero value. Otherwise, btrfs_remount() does not seem to have any problem with the transition from 'ro' to 'rw'.
-- chandan -- 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
