On Tue, Feb 21, 2017 at 08:43:58PM +0100, Artur Paszkiewicz wrote:
> Add 'consistency_policy' attribute for array. It indicates how the array
> maintains consistency in case of unexpected shutdown.
>
> Add 'ppl_sector' and 'ppl_size' for rdev, which describe the location
> and size of the PPL space on the device. They can't be changed for
> active members if the array is started and PPL is enabled, so in the
> setter functions only basic checks are performed. More checks are done
> in ppl_validate_rdev() when starting the log.
>
> These attributes are writable to allow enabling PPL for external
> metadata arrays and (later) to enable/disable PPL for a running array.
>
> Signed-off-by: Artur Paszkiewicz <artur.paszkiewicz@xxxxxxxxx>
> ---
> Documentation/admin-guide/md.rst | 32 ++++++++++-
> drivers/md/md.c | 115 +++++++++++++++++++++++++++++++++++++++
> 2 files changed, 144 insertions(+), 3 deletions(-)
>
> diff --git a/Documentation/admin-guide/md.rst b/Documentation/admin-guide/md.rst
> index 1e61bf50595c..84de718f24a4 100644
> --- a/Documentation/admin-guide/md.rst
> +++ b/Documentation/admin-guide/md.rst
> @@ -276,14 +276,14 @@ All md devices contain:
> array creation it will default to 0, though starting the array as
> ``clean`` will set it much larger.
>
> - new_dev
> + new_dev
> This file can be written but not read. The value written should
> be a block device number as major:minor. e.g. 8:0
> This will cause that device to be attached to the array, if it is
> available. It will then appear at md/dev-XXX (depending on the
> name of the device) and further configuration is then possible.
>
> - safe_mode_delay
> + safe_mode_delay
> When an md array has seen no write requests for a certain period
> of time, it will be marked as ``clean``. When another write
> request arrives, the array is marked as ``dirty`` before the write
> @@ -292,7 +292,7 @@ All md devices contain:
> period as a number of seconds. The default is 200msec (0.200).
> Writing a value of 0 disables safemode.
>
> - array_state
> + array_state
> This file contains a single word which describes the current
> state of the array. In many cases, the state can be set by
> writing the word for the desired state, however some states
> @@ -401,7 +401,30 @@ All md devices contain:
> once the array becomes non-degraded, and this fact has been
> recorded in the metadata.
>
> + consistency_policy
> + This indicates how the array maintains consistency in case of unexpected
> + shutdown. It can be:
>
> + none
> + Array has no redundancy information, e.g. raid0, linear.
> +
> + resync
> + Full resync is performed and all redundancy is regenerated when the
> + array is started after unclean shutdown.
> +
> + bitmap
> + Resync assisted by a write-intent bitmap.
> +
> + journal
> + For raid4/5/6, journal device is used to log transactions and replay
> + after unclean shutdown.
> +
> + ppl
> + For raid5 only, Partial Parity Log is used to close the write hole and
> + eliminate resync.
> +
> + The accepted values when writing to this file are ``ppl`` and ``resync``,
> + used to enable and disable PPL.
>
>
> As component devices are added to an md array, they appear in the ``md``
> @@ -563,6 +586,9 @@ Each directory contains:
> adds bad blocks without acknowledging them. This is largely
> for testing.
>
> + ppl_sector, ppl_size
> + Location and size (in sectors) of the space used for Partial Parity Log
> + on this device.
>
>
> An active md device will also contain an entry for each active device
> diff --git a/drivers/md/md.c b/drivers/md/md.c
> index c2028007b209..3ff979d538d4 100644
> --- a/drivers/md/md.c
> +++ b/drivers/md/md.c
> @@ -3157,6 +3157,78 @@ static ssize_t ubb_store(struct md_rdev *rdev, const char *page, size_t len)
> static struct rdev_sysfs_entry rdev_unack_bad_blocks =
> __ATTR(unacknowledged_bad_blocks, S_IRUGO|S_IWUSR, ubb_show, ubb_store);
>
> +static ssize_t
> +ppl_sector_show(struct md_rdev *rdev, char *page)
> +{
> + return sprintf(page, "%llu\n", (unsigned long long)rdev->ppl.sector);
> +}
> +
> +static ssize_t
> +ppl_sector_store(struct md_rdev *rdev, const char *buf, size_t len)
> +{
> + unsigned long long sector;
> +
> + if (kstrtoull(buf, 10, §or) < 0)
> + return -EINVAL;
Maybe use base 0 to be more friendly
> + if (sector != (sector_t)sector)
> + return -EINVAL;
> +
> + if (rdev->mddev->pers && test_bit(MD_HAS_PPL, &rdev->mddev->flags) &&
> + rdev->raid_disk >= 0)
> + return -EBUSY;
> +
> + if (rdev->mddev->persistent) {
> + if (rdev->mddev->major_version == 0)
> + return -EINVAL;
> + if ((sector > rdev->sb_start &&
> + sector - rdev->sb_start > S16_MAX) ||
> + (sector < rdev->sb_start &&
> + rdev->sb_start - sector > -S16_MIN))
> + return -EINVAL;
Don't check if the address overlaps with data?
> + rdev->ppl.offset = sector - rdev->sb_start;
> + } else if (!rdev->mddev->external) {
> + return -EBUSY;
> + }
generally we don't use {} for single line code
Thanks,
Shaohua
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