kernel/linux.git/fs/nfs/export.c, branch linux-6.0.y

nfs: block notification on fs with its own ->lock

2022-01-08T19:42:01+00:00

NFSv4.1 supports an optional lock notification feature which notifies the client when a lock comes available. (Normally NFSv4 clients just poll for locks if necessary.) To make that work, we need to request a blocking lock from the filesystem. We turned that off for NFS in commit f657f8eef3ff ("nfs: don't atempt blocking locks on nfs reexports") [sic] because it actually blocks the nfsd thread while waiting for the lock. Thanks to Vasily Averin for pointing out that NFS isn't the only filesystem with that problem. Any filesystem that leaves ->lock NULL will use posix_lock_file(), which does the right thing. Simplest is just to assume that any filesystem that defines its own ->lock is not safe to request a blocking lock from. So, this patch mostly reverts commit f657f8eef3ff ("nfs: don't atempt blocking locks on nfs reexports") [sic] and commit b840be2f00c0 ("lockd: don't attempt blocking locks on nfs reexports"), and instead uses a check of ->lock (Vasily's suggestion) to decide whether to support blocking lock notifications on a given filesystem. Also add a little documentation. Perhaps someday we could add back an export flag later to allow filesystems with "good" ->lock methods to support blocking lock notifications. Reported-by: Vasily Averin Signed-off-by: J. Bruce Fields [ cel: Description rewritten to address checkpatch nits ] [ cel: Fixed warning when SUNRPC debugging is disabled ] [ cel: Fixed NULL check ] Signed-off-by: Chuck Lever Reviewed-by: Vasily Averin

NFS: Remove the nfs4_label argument from nfs_fhget()

2021-11-05T18:54:40+00:00

Signed-off-by: Anna Schumaker Signed-off-by: Trond Myklebust

NFS: Remove the nfs4_label from the nfs4_getattr_res

2021-11-05T18:54:39+00:00

Signed-off-by: Anna Schumaker Signed-off-by: Trond Myklebust

NFS: Remove the nfs4_label from the nfs4_lookupp_res struct

2021-11-05T18:54:39+00:00

Signed-off-by: Anna Schumaker Signed-off-by: Trond Myklebust

nfs: don't atempt blocking locks on nfs reexports

2021-08-26T19:32:10+00:00

NFS implements blocking locks by blocking inside its lock method. In the reexport case, this blocks the nfs server thread, which could lead to deadlocks since an nfs server thread might be required to unlock the conflicting lock. It also causes a crash, since the nfs server thread assumes it can free the lock when its lm_notify lock callback is called. Ideal would be to make the nfs lock method return without blocking in this case, but for now it works just not to attempt blocking locks. The difference is just that the original client will have to poll (as it does in the v4.0 case) instead of getting a callback when the lock's available. Signed-off-by: J. Bruce Fields Acked-by: Anna Schumaker Signed-off-by: Chuck Lever

NFS: Add a cache validity flag argument to nfs_revalidate_inode()

2021-04-13T00:11:44+00:00

Add an argument to nfs_revalidate_inode() to allow callers to specify which attributes they need to check for validity. Signed-off-by: Trond Myklebust

NFS: fix nfs_fetch_iversion()

2021-04-05T13:04:21+00:00

The change attribute is always set by all NFS client versions so get rid of the open-coded version. Fixes: 3cc55f4434b4 ("nfs: use change attribute for NFS re-exports") Signed-off-by: Trond Myklebust

nfs: use change attribute for NFS re-exports

2021-01-30T16:47:12+00:00

When exporting NFS, we may as well use the real change attribute returned by the original server instead of faking up a change attribute from the ctime. Note we can't do that by setting I_VERSION--that would also turn on the logic in iversion.h which treats the lower bit specially, and that doesn't make sense for NFS. So instead we define a new export operation for filesystems like NFS that want to manage the change attribute themselves. Signed-off-by: J. Bruce Fields Reviewed-by: Christoph Hellwig Signed-off-by: Chuck Lever

nfsd: Record NFSv4 pre/post-op attributes as non-atomic

2020-12-09T14:39:38+00:00

For the case of NFSv4, specify to the client that the pre/post-op attributes were not recorded atomically with the main operation. Signed-off-by: Trond Myklebust Signed-off-by: Chuck Lever

nfsd: Set PF_LOCAL_THROTTLE on local filesystems only

2020-12-09T14:39:38+00:00

Don't set PF_LOCAL_THROTTLE on remote filesystems like NFS, since they aren't expected to ever be subject to double buffering. Signed-off-by: Trond Myklebust Signed-off-by: Chuck Lever