• Trond Myklebust's avatar
    NFS: Fix a race in nfs_sync_inode() · c42de9dd
    Trond Myklebust authored
    Kudos to Neil Brown for spotting the problem:
    
    "in nfs_sync_inode, there is effectively the sequence:
    
       nfs_wait_on_requests
       nfs_flush_inode
       nfs_commit_inode
    
     This seems a bit racy to me as if the only requests are on the
     ->commit list, and nfs_commit_inode is called separately after
     nfs_wait_on_requests completes, and before nfs_commit_inode start
     (say: by nfs_write_inode) then none of these function will return
     >0, yet there will be some pending request that aren't waited for."
    
    The solution is to search for requests to wait upon, search for dirty
    requests, and search for uncommitted requests while holding the
    nfsi->req_lock
    
    The patch also cleans up nfs_sync_inode(), getting rid of the redundant
    FLUSH_WAIT flag. It turns out that we were always setting it.
    Signed-off-by: default avatarTrond Myklebust <Trond.Myklebust@netapp.com>
    c42de9dd
write.c 40.3 KB