Messages in this thread | | | Date | Fri, 06 Oct 2006 15:50:12 -0500 | From | Eric Sandeen <> | Subject | Re: [RFC] Reverting "bd_mount_mutex" to "bd_mount_sem" |
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Ingo Molnar wrote: > * Srinivasa Ds <srinivasa@in.ibm.com> wrote: > >> On debugging I found out that,"dmsetup suspend <device name>" calls >> "freeze_bdev()",which locks "bd_mount_mutex" to make sure that no new >> mounts happen on bdev until thaw_bdev() is called. >> This "thaw_bdev()" is getting called when we resume the device >> through "dmsetup resume <device-name>". >> Hence we have 2 processes,one of which locks >> "bd_mount_mutex"(dmsetup suspend) and Another(dmsetup resume) unlocks >> it. > > hm, to me this seems quite a fragile construct - even if the > mutex-debugging warning is worked around by reverting to a semaphore. > > Ingo
Ingo, what do you feel is fragile about this? It seems like this is a reasonable way to go, except that maybe a down_trylock would be good if a 2nd process tries to freeze while it's already frozen...
Thanks,
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