NFS: Fix a race when doing NFS write coalescing

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Currently we do write coalescing in a very inefficient manner: one pass in
generic_writepages() in order to lock the pages for writing, then one pass
in nfs_flush_mapping() and/or nfs_sync_mapping_wait() in order to gather
the locked pages for coalescing into RPC requests of size "wsize".

In fact, it turns out there is actually a deadlock possible here since we
only start I/O on the second pass. If the user signals the process while
we're in nfs_sync_mapping_wait(), for instance, then we may exit before
starting I/O on all the requests that have been queued up.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

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This commit is contained in:

Trond Myklebust 2007-04-02 19:29:52 -04:00

parent 8b09bee308

commit c63c7b0513

4 changed files with 50 additions and 201 deletions

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92

fs/nfs/pagelist.c

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149

fs/nfs/write.c

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8

include/linux/nfs_page.h

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2

include/linux/writeback.h

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