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| author | Mikulas Patocka <mpatocka@redhat.com> | 2013-11-01 18:27:41 -0400 |
|---|---|---|
| committer | Mike Snitzer <snitzer@redhat.com> | 2013-11-09 18:20:22 -0500 |
| commit | 2c140a246dc0bc085b98eddde978060fcec1080c (patch) | |
| tree | 73d747f4422fe202868495d08ea5d189bc16bd79 /drivers/md/dm.h | |
| parent | 7833b08e18241a1c35c09ef38be840cbf6c58acf (diff) | |
| download | lwn-2c140a246dc0bc085b98eddde978060fcec1080c.tar.gz lwn-2c140a246dc0bc085b98eddde978060fcec1080c.zip | |
dm: allow remove to be deferred
This patch allows the removal of an open device to be deferred until
it is closed. (Previously such a removal attempt would fail.)
The deferred remove functionality is enabled by setting the flag
DM_DEFERRED_REMOVE in the ioctl structure on DM_DEV_REMOVE or
DM_REMOVE_ALL ioctl.
On return from DM_DEV_REMOVE, the flag DM_DEFERRED_REMOVE indicates if
the device was removed immediately or flagged to be removed on close -
if the flag is clear, the device was removed.
On return from DM_DEV_STATUS and other ioctls, the flag
DM_DEFERRED_REMOVE is set if the device is scheduled to be removed on
closure.
A device that is scheduled to be deleted can be revived using the
message "@cancel_deferred_remove". This message clears the
DMF_DEFERRED_REMOVE flag so that the device won't be deleted on close.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Diffstat (limited to 'drivers/md/dm.h')
| -rw-r--r-- | drivers/md/dm.h | 13 |
1 files changed, 12 insertions, 1 deletions
diff --git a/drivers/md/dm.h b/drivers/md/dm.h index 1d1ad7b7e527..c57ba550f69e 100644 --- a/drivers/md/dm.h +++ b/drivers/md/dm.h @@ -129,6 +129,16 @@ int dm_deleting_md(struct mapped_device *md); int dm_suspended_md(struct mapped_device *md); /* + * Test if the device is scheduled for deferred remove. + */ +int dm_test_deferred_remove_flag(struct mapped_device *md); + +/* + * Try to remove devices marked for deferred removal. + */ +void dm_deferred_remove(void); + +/* * The device-mapper can be driven through one of two interfaces; * ioctl or filesystem, depending which patch you have applied. */ @@ -158,7 +168,8 @@ void dm_stripe_exit(void); void dm_destroy(struct mapped_device *md); void dm_destroy_immediate(struct mapped_device *md); int dm_open_count(struct mapped_device *md); -int dm_lock_for_deletion(struct mapped_device *md); +int dm_lock_for_deletion(struct mapped_device *md, bool mark_deferred, bool only_deferred); +int dm_cancel_deferred_remove(struct mapped_device *md); int dm_request_based(struct mapped_device *md); sector_t dm_get_size(struct mapped_device *md); struct dm_stats *dm_get_stats(struct mapped_device *md); |