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author | Mike Snitzer <snitzer@redhat.com> | 2009-12-10 23:52:24 +0000 |
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committer | Alasdair G Kergon <agk@redhat.com> | 2009-12-10 23:52:24 +0000 |
commit | c1f0c183f6acc6d32c5a1d0249ec68bf783af7b1 (patch) | |
tree | f8e8e88e5403a9dbbebff14dc4afd6d475d1c03a /drivers/i2c/i2c-core.h | |
parent | 042d2a9bcd80fe12d4b0871706aa9dd2231e8238 (diff) | |
download | op-kernel-dev-c1f0c183f6acc6d32c5a1d0249ec68bf783af7b1.zip op-kernel-dev-c1f0c183f6acc6d32c5a1d0249ec68bf783af7b1.tar.gz |
dm snapshot: allow live exception store handover between tables
Permit in-use snapshot exception data to be 'handed over' from one
snapshot instance to another. This is a pre-requisite for patches
that allow the changes made in a snapshot device to be merged back into
its origin device and also allows device resizing.
The basic call sequence is:
dmsetup load new_snapshot (referencing the existing in-use cow device)
- the ctr code detects that the cow is already in use and allows the
two snapshot target instances to be linked together
dmsetup suspend original_snapshot
dmsetup resume new_snapshot
- the new_snapshot becomes live, and if anything now tries to access
the original one it will receive -EIO
dmsetup remove original_snapshot
(There can only be two snapshot targets referencing the same cow device
simultaneously.)
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Diffstat (limited to 'drivers/i2c/i2c-core.h')
0 files changed, 0 insertions, 0 deletions