kernel.git/fs/nfsd/trace.h, branch linux-6.7.y

NFSD: Fix nfsd_clid_class use of __string_len() macro

2024-04-03T13:11:29Z

[ Upstream commit 9388a2aa453321bcf1ad2603959debea9e6ab6d4 ] I'm working on restructuring the __string* macros so that it doesn't need to recalculate the string twice. That is, it will save it off when processing __string() and the __assign_str() will not need to do the work again as it currently does. Currently __string_len(item, src, len) doesn't actually use "src", but my changes will require src to be correct as that is where the __assign_str() will get its value from. The event class nfsd_clid_class has: __string_len(name, name, clp->cl_name.len) But the second "name" does not exist and causes my changes to fail to build. That second parameter should be: clp->cl_name.data. Link: https://lore.kernel.org/linux-trace-kernel/20240222122828.3d8d213c@gandalf.local.home Cc: Neil Brown Cc: Olga Kornievskaia Cc: Dai Ngo Cc: Tom Talpey Cc: stable@vger.kernel.org Fixes: d27b74a8675ca ("NFSD: Use new __string_len C macros for nfsd_clid_class") Acked-by: Chuck Lever Acked-by: Jeff Layton Signed-off-by: Steven Rostedt (Google) Signed-off-by: Sasha Levin

NFSD: add trace points to track server copy progress

2023-10-16T16:44:00Z

Add trace points on destination server to track inter and intra server copy operations. Signed-off-by: Dai Ngo Tested-by: Chen Hanxiao Signed-off-by: Chuck Lever

NFSD: Rename struct svc_cacherep

2023-08-29T21:45:22Z

The svc_ prefix is identified with the SunRPC layer. Although the duplicate reply cache caches RPC replies, it is only for the NFS protocol. Rename the struct to better reflect its purpose. Reviewed-by: Jeff Layton Signed-off-by: Chuck Lever

NFSD: Replace nfsd_prune_bucket()

2023-08-29T21:45:22Z

Enable nfsd_prune_bucket() to drop the bucket lock while calling kfree(). Use the same pattern that Jeff recently introduced in the NFSD filecache. A few percpu operations are moved outside the lock since they temporarily disable local IRQs which is expensive and does not need to be done while the lock is held. Reviewed-by: Jeff Layton Signed-off-by: Chuck Lever

NFSD: Enable write delegation support

2023-08-29T21:45:22Z

This patch grants write delegations for OPEN with NFS4_SHARE_ACCESS_WRITE if there is no conflict with other OPENs. Write delegation conflicts with another OPEN, REMOVE, RENAME and SETATTR are handled the same as read delegation using notify_change, try_break_deleg. The NFSv4.0 protocol does not enable a server to determine that a conflicting GETATTR originated from the client holding the delegation versus coming from some other client. With NFSv4.1 and later, the SEQUENCE operation that begins each COMPOUND contains a client ID, so delegation recall can be safely squelched in this case. With NFSv4.0, however, the server must recall or send a CB_GETATTR (per RFC 7530 Section 16.7.5) even when the GETATTR originates from the client holding that delegation. An NFSv4.0 client can trigger a pathological situation if it always sends a DELEGRETURN preceded by a conflicting GETATTR in the same COMPOUND. COMPOUND execution will always stop at the GETATTR and the DELEGRETURN will never get executed. The server eventually revokes the delegation, which can result in loss of open or lock state. Tracepoint added to track whether read or write delegation is granted. Signed-off-by: Dai Ngo Signed-off-by: Jeff Layton Signed-off-by: Chuck Lever

NFSD: trace nfsctl operations

2023-06-05T13:01:43Z

Add trace log eye-catchers that record the arguments used to configure NFSD. This helps when troubleshooting the NFSD administrative interfaces. These tracepoints can capture NFSD start-up and shutdown times and parameters, changes in lease time and thread count, and a request to end the namespace's NFSv4 grace period, in addition to the set of NFS versions that are enabled. Reviewed-by: Jeff Layton Signed-off-by: Chuck Lever

NFSD: Remove open coding of string copy

2023-05-15T12:03:04Z

Instead of open coding a __dynamic_array(), use the __string() and __assign_str() helper macros that exist for this kind of use case. Part of an effort to remove deprecated strlcpy() [1] completely from the kernel[2]. [1] https://www.kernel.org/doc/html/latest/process/deprecated.html#strlcpy [2] https://github.com/KSPP/linux/issues/89 Fixes: 3c92fba557c6 ("NFSD: Enhance the nfsd_cb_setup tracepoint") Signed-off-by: Azeem Shaikh Reviewed-by: Jeff Layton Signed-off-by: Chuck Lever

nfsd: don't fsync nfsd_files on last close

2023-02-20T14:20:59Z

Most of the time, NFSv4 clients issue a COMMIT before the final CLOSE of an open stateid, so with NFSv4, the fsync in the nfsd_file_free path is usually a no-op and doesn't block. We have a customer running knfsd over very slow storage (XFS over Ceph RBD). They were using the "async" export option because performance was more important than data integrity for this application. That export option turns NFSv4 COMMIT calls into no-ops. Due to the fsync in this codepath however, their final CLOSE calls would still stall (since a CLOSE effectively became a COMMIT). I think this fsync is not strictly necessary. We only use that result to reset the write verifier. Instead of fsync'ing all of the data when we free an nfsd_file, we can just check for writeback errors when one is acquired and when it is freed. If the client never comes back, then it'll never see the error anyway and there is no point in resetting it. If an error occurs after the nfsd_file is removed from the cache but before the inode is evicted, then it will reset the write verifier on the next nfsd_file_acquire, (since there will be an unseen error). The only exception here is if something else opens and fsyncs the file during that window. Given that local applications work with this limitation today, I don't see that as an issue. Link: https://bugzilla.redhat.com/show_bug.cgi?id=2166658 Fixes: ac3a2585f018 ("nfsd: rework refcounting in filecache") Reported-and-tested-by: Pierguido Lambri Signed-off-by: Jeff Layton Signed-off-by: Chuck Lever

nfsd: fix handling of cached open files in nfsd4_open codepath

2023-01-06T18:17:06Z

Commit fb70bf124b05 ("NFSD: Instantiate a struct file when creating a regular NFSv4 file") added the ability to cache an open fd over a compound. There are a couple of problems with the way this currently works: It's racy, as a newly-created nfsd_file can end up with its PENDING bit cleared while the nf is hashed, and the nf_file pointer is still zeroed out. Other tasks can find it in this state and they expect to see a valid nf_file, and can oops if nf_file is NULL. Also, there is no guarantee that we'll end up creating a new nfsd_file if one is already in the hash. If an extant entry is in the hash with a valid nf_file, nfs4_get_vfs_file will clobber its nf_file pointer with the value of op_file and the old nf_file will leak. Fix both issues by making a new nfsd_file_acquirei_opened variant that takes an optional file pointer. If one is present when this is called, we'll take a new reference to it instead of trying to open the file. If the nfsd_file already has a valid nf_file, we'll just ignore the optional file and pass the nfsd_file back as-is. Also rework the tracepoints a bit to allow for an "opened" variant and don't try to avoid counting acquisitions in the case where we already have a cached open file. Fixes: fb70bf124b05 ("NFSD: Instantiate a struct file when creating a regular NFSv4 file") Cc: Trond Myklebust Reported-by: Stanislav Saner Reported-and-Tested-by: Ruben Vestergaard Reported-and-Tested-by: Torkil Svensgaard Signed-off-by: Jeff Layton Signed-off-by: Chuck Lever

nfsd: rework refcounting in filecache

2022-12-11T16:03:09Z

The filecache refcounting is a bit non-standard for something searchable by RCU, in that we maintain a sentinel reference while it's hashed. This in turn requires that we have to do things differently in the "put" depending on whether its hashed, which we believe to have led to races. There are other problems in here too. nfsd_file_close_inode_sync can end up freeing an nfsd_file while there are still outstanding references to it, and there are a number of subtle ToC/ToU races. Rework the code so that the refcount is what drives the lifecycle. When the refcount goes to zero, then unhash and rcu free the object. A task searching for a nfsd_file is allowed to bump its refcount, but only if it's not already 0. Ensure that we don't make any other changes to it until a reference is held. With this change, the LRU carries a reference. Take special care to deal with it when removing an entry from the list, and ensure that we only repurpose the nf_lru list_head when the refcount is 0 to ensure exclusive access to it. Signed-off-by: Jeff Layton Signed-off-by: Chuck Lever