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Re: inconsistent file content after killing nfs daemon


On Wed, Jan 16, 2002 at 10:36:25AM +0100, eric chacron wrote:
> Even in synchronous mode (O_SYNC ...), it seems the nfs client sends as many
> write request to the server as the user data is splitted into cache pages on
> client side (ref.  nfs_writepage_sync() , nfs_writepage() in fs/nfs/write.c
> ,nfs_updatepage() in fs/nfs/write.c , nfs_commit_write() in fs/nfs/file.c ,
> generic_file_write() in mm/filemap.c , nfs_file_write in fs/nfs/file.c)

That's correct.  O_SYNC guarantees that all of the data gets sent to
the server before the call returns, but does not guarantee order of
data within the write.  There *are* no guarantees for that in Unix
semantics, anywhere.

> I propose the following conditions to provide atomicity of write through nsf +
> ext3, with the current implementation:

It could change at any time.  It is really up to the application to
make its own provision for atomicity.


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