Messages in this thread | | | Date | Tue, 24 Jan 2006 20:18:21 +0300 | From | Kirill Korotaev <> | Subject | Re: [PATCH] shrink_dcache_parent() races against shrink_dcache_memory() |
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>><<<< and here, when you drop sb_lock, and dentry->d_lock/dcache_lock in >>prune_dentry() it looks to me that we have exactly the same situation as >>it was without your patch: >><<<< another CPU can start umount in parallel. >><<<< maybe sb_lock barrier helps this somehow, but I can't see how yet... > >>From the unmount path, __mntput() is called. It sets s_active to 0 in > deactivate_super(), hence our check would prevent us from pruning a dentry > that is a part of a super block that is going to go away soon. The idea > is to let the unmount do all the work here, the allocator can concentrate > on other dentries. you check can happen 1 nanosecond before it sets s_active, after that the code goes into prune_dentry(), while deactivate_super() successfully sets s_active and starts umount main job. Nothing prevents the race... :(
Kirill
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