Messages in this thread | | | Date | Tue, 7 Nov 2006 23:49:51 +0000 | From | Alasdair G Kergon <> | Subject | Re: [PATCH 2.6.19 5/5] fs: freeze_bdev with semaphore not mutex |
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On Wed, Nov 08, 2006 at 12:05:49AM +0100, Rafael J. Wysocki wrote: > But freeze_bdev() is supposed to return the result of get_super(bdev) > _unconditionally_. Moreover, in its current form freeze_bdev() _cannot_ > _fail_, so I don't see how this change doesn't break any existing code. > For example freeze_filesystems() (recently added to -mm) will be broken > if the down_trylock() is unsuccessful.
I hadn't noticed that -mm patch. I'll take a look. Up to now, device-mapper (via dmsetup) and xfs (via xfs_freeze, which dates from before device-mapper handled this automatically) were the only users. Only one freeze should be issued at once. A freeze is a temporary thing, normally used while creating a snapshot. (One problem we still have is lots of old documentation on the web advising people to run xfs_freeze before creating device-mapper snapshots.)
You're right that the down_trylock idea is more trouble than it's worth and should be scrapped.
Alasdair -- agk@redhat.com - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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