Messages in this thread | | | Date | Wed, 9 May 2001 19:38:01 -0300 (BRT) | From | Marcelo Tosatti <> | Subject | Re: nfs MAP_SHARED corruption fix |
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On Thu, 10 May 2001, Andrea Arcangeli wrote:
> On Wed, May 09, 2001 at 07:02:16PM -0300, Marcelo Tosatti wrote: > > Why don't you clean I_DIRTY_PAGES ? > > we don't have visibilty on the inode_lock from there, we could make a > function in fs/inode.c or export the inode_lock to do that, but the flag > will be collected when the inode is released anyways, and it's only an > hint to make the common case fast (the common case is when nobody ever > did a MAP_SHARED on the inode). Other places msync/fsync doesn't even > check for such bit but they fdatasync/fdatawait unconditionally.
Actually msync/fsync _can't_ rely on this bit because there is no guarantee that data is fully synced on disk even if the bit is cleared. (__sync_one (fs/inode.c) clears the bit _before_ starting the writeout, and thats it).
You have the same problem with your code, so I guess its better to just remove the I_DIRTY_PAGES check.
> And on the same lines also sys_fsync and sys_msync could clear the > I_DIRTY_PAGES but they don't for semplcity (it will be cleared by > kupdate later). > > So in short we can clear it but it's not required and it won't make much > difference. If you really care you can clear it before calling fdatasync > though.
Well, forget about that. :)
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