| Message ID | 5057CE50.1050706@jp.fujitsu.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Tue, Sep 18, 2012 at 10:28:48AM +0900, Hidetoshi Seto wrote: > This patch create space to hold default mount option, > and to use saved default mount option change super.c > to read default mount option first when mount devices. > > Signed-off-by: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com> > --- > fs/btrfs/ctree.h | 5 ++++- > fs/btrfs/super.c | 2 ++ > 2 files changed, 6 insertions(+), 1 deletions(-) > > diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h > index fa5c45b..3eb0551 100644 > --- a/fs/btrfs/ctree.h > +++ b/fs/btrfs/ctree.h > @@ -458,8 +458,11 @@ struct btrfs_super_block { > > __le64 cache_generation; > > + /* default mount options */ > + unsigned long default_mount_opt; you need to use __le64 here, unsigned long has not fixed size > + > /* future expansion */ > - __le64 reserved[31]; > + __le64 reserved[30]; > u8 sys_chunk_array[BTRFS_SYSTEM_CHUNK_ARRAY_SIZE]; > struct btrfs_root_backup super_roots[BTRFS_NUM_BACKUP_ROOTS]; > } __attribute__ ((__packed__)); > diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c > index e239915..7ef4a2e 100644 > --- a/fs/btrfs/super.c > +++ b/fs/btrfs/super.c > @@ -340,6 +340,8 @@ int btrfs_parse_options(struct btrfs_root *root, char *options) > char *compress_type; > bool compress_force = false; > > + info->mount_opt = info->super_copy->default_mount_opt; the options have to respect some priority, eg. when I set default options to a filesystem, but mount with a different set, I expect that the explicit flags apply and override the defaults. I don't remember if this was discussed in the mailinglist or on IRC only, should be easy to dig up if needed. > + > cache_gen = btrfs_super_cache_generation(root->fs_info->super_copy); > if (cache_gen) > btrfs_set_opt(info->mount_opt, SPACE_CACHE); 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
(2012/09/18 21:10), David Sterba wrote: > On Tue, Sep 18, 2012 at 10:28:48AM +0900, Hidetoshi Seto wrote: >> diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h >> index fa5c45b..3eb0551 100644 >> --- a/fs/btrfs/ctree.h >> +++ b/fs/btrfs/ctree.h >> @@ -458,8 +458,11 @@ struct btrfs_super_block { >> >> __le64 cache_generation; >> >> + /* default mount options */ >> + unsigned long default_mount_opt; > > you need to use __le64 here, unsigned long has not fixed size Indeed. I'll use __le64 next time. >> diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c >> index e239915..7ef4a2e 100644 >> --- a/fs/btrfs/super.c >> +++ b/fs/btrfs/super.c >> @@ -340,6 +340,8 @@ int btrfs_parse_options(struct btrfs_root *root, char *options) >> char *compress_type; >> bool compress_force = false; >> >> + info->mount_opt = info->super_copy->default_mount_opt; > > the options have to respect some priority, eg. when I set default > options to a filesystem, but mount with a different set, I expect that > the explicit flags apply and override the defaults. > > I don't remember if this was discussed in the mailinglist or on IRC > only, should be easy to dig up if needed. At least I don't know whether this was already disscussed or not. Now my code gives priority to the default options, and it would not be so difficult in case if we have opposing options like "ssd" vs "nossd", and "space_cache" vs "no_space_cache"... Or we could use the default options only if there is no options specified when it is being mount, but it will make the default options useless. Humm, I'll try to pull together my thoughts prior to my next post. Thanks, H.Seto -- 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 Wed, Sep 19, 2012 at 05:31:25PM +0900, Hidetoshi Seto wrote: > >> > >> + info->mount_opt = info->super_copy->default_mount_opt; > > > > the options have to respect some priority, eg. when I set default > > options to a filesystem, but mount with a different set, I expect that > > the explicit flags apply and override the defaults. > > > > I don't remember if this was discussed in the mailinglist or on IRC > > only, should be easy to dig up if needed. > > At least I don't know whether this was already disscussed or not. For the subset you've selected, whole-fs default options, I now think we don't need it, the discussions we had were about option precedence for per -file, -subvolume, -fs, -mount. At the time of mount only per-mount and per-fs need to sort their precedence. Any per-file option has to be evaluated at a specific time eg. when new data are written in case of compression. > Now my code gives priority to the default options, and it would not > be so difficult in case if we have opposing options like "ssd" vs > "nossd", and "space_cache" vs "no_space_cache"... Yep, that's what I expect to temporarily disable a specific option, eg. the space_cache. For that purpose the full set of options with their no- counterparts would make sense from the usability POV (although there may be exceptions). > Or we could use the default options only if there is no options > specified when it is being mount, but it will make the default > options useless. You mean in case of a simple mount /dev/ice /mnt ? This seems like a limited use of the defaults and may be confusing. 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
diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h index fa5c45b..3eb0551 100644 --- a/fs/btrfs/ctree.h +++ b/fs/btrfs/ctree.h @@ -458,8 +458,11 @@ struct btrfs_super_block { __le64 cache_generation; + /* default mount options */ + unsigned long default_mount_opt; + /* future expansion */ - __le64 reserved[31]; + __le64 reserved[30]; u8 sys_chunk_array[BTRFS_SYSTEM_CHUNK_ARRAY_SIZE]; struct btrfs_root_backup super_roots[BTRFS_NUM_BACKUP_ROOTS]; } __attribute__ ((__packed__)); diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c index e239915..7ef4a2e 100644 --- a/fs/btrfs/super.c +++ b/fs/btrfs/super.c @@ -340,6 +340,8 @@ int btrfs_parse_options(struct btrfs_root *root, char *options) char *compress_type; bool compress_force = false; + info->mount_opt = info->super_copy->default_mount_opt; + cache_gen = btrfs_super_cache_generation(root->fs_info->super_copy); if (cache_gen) btrfs_set_opt(info->mount_opt, SPACE_CACHE);
This patch create space to hold default mount option, and to use saved default mount option change super.c to read default mount option first when mount devices. Signed-off-by: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com> --- fs/btrfs/ctree.h | 5 ++++- fs/btrfs/super.c | 2 ++ 2 files changed, 6 insertions(+), 1 deletions(-)