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path: root/fs/nfsd/filecache.h
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2022-01-08nfsd: Replace use of rwsem with errseq_tTrond Myklebust1-1/+0
The nfsd_file nf_rwsem is currently being used to separate file write and commit instances to ensure that we catch errors and apply them to the correct write/commit. We can improve scalability at the expense of a little accuracy (some extra false positives) by replacing the nf_rwsem with more careful use of the errseq_t mechanism to track errors across the different operations. Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com> Signed-off-by: Chuck Lever <chuck.lever@oracle.com> [ cel: rebased on zero-verifier fix ]
2020-02-06nfsd: convert file cache to use over/underflow safe refcountTrond Myklebust1-2/+2
Use the 'refcount_t' type instead of 'atomic_t' for improved refcounting safety. Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com> Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2020-01-23nfsd: Fix stable writesTrond Myklebust1-0/+1
Strictly speaking, a stable write error needs to reflect the write + the commit of that write (and only that write). To ensure that we don't pick up the write errors from other writebacks, add a rw_semaphore to provide exclusion. Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com> Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2020-01-23nfsd: Containerise filecache laundretteTrond Myklebust1-0/+2
Ensure that if the filecache laundrette gets stuck, it only affects the knfsd instances of one container. The notifier callbacks can be called from various contexts so avoid using synchonous filesystem operations that might deadlock. Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com> Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2019-09-10nfsd: nfsd_file cache entries should be per net namespaceTrond Myklebust1-1/+2
Ensure that we can safely clear out the file cache entries when the nfs server is shut down on a container. Otherwise, the file cache may end up pinning the mounts. Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com> Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2019-08-19nfsd: add a new struct file caching facility to nfsdJeff Layton1-0/+60
Currently, NFSv2/3 reads and writes have to open a file, do the read or write and then close it again for each RPC. This is highly inefficient, especially when the underlying filesystem has a relatively slow open routine. This patch adds a new open file cache to knfsd. Rather than doing an open for each RPC, the read/write handlers can call into this cache to see if there is one already there for the correct filehandle and NFS_MAY_READ/WRITE flags. If there isn't an entry, then we create a new one and attempt to perform the open. If there is, then we wait until the entry is fully instantiated and return it if it is at the end of the wait. If it's not, then we attempt to take over construction. Since the main goal is to speed up NFSv2/3 I/O, we don't want to close these files on last put of these objects. We need to keep them around for a little while since we never know when the next READ/WRITE will come in. Cache entries have a hardcoded 1s timeout, and we have a recurring workqueue job that walks the cache and purges any entries that have expired. Signed-off-by: Jeff Layton <jeff.layton@primarydata.com> Signed-off-by: Weston Andros Adamson <dros@primarydata.com> Signed-off-by: Richard Sharpe <richard.sharpe@primarydata.com> Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com> Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com> Signed-off-by: J. Bruce Fields <bfields@redhat.com>