afs: Further fix file locking
Further fix the file locking in the afs filesystem client in a number of ways, including: (1) Don't submit the operation to obtain a lock from the server in a work queue context, but rather do it in the process context of whoever issued the requesting system call. (2) The owner of the file_lock struct at the front of the pending_locks queue now owns right to talk to the server. (3) Write locks can be instantly granted if they don't overlap with any other locks *and* we have a write lock on the server. (4) In the event of an authentication/permission error, all other matching pending locks requests are also immediately aborted. (5) Properly use VFS core locks_lock_file_wait() to distribute the server lock amongst local client locks, including waiting for the lock to become available. Test with: sqlite3 /afs/.../scratch/billings.sqlite <<EOF CREATE TABLE hosts ( hostname varchar(80), shorthost varchar(80), room varchar(30), building varchar(30), PRIMARY KEY(shorthost) ); EOF With the version of sqlite3 that I have, this should fail consistently with EAGAIN, whether or not the program is straced (which introduces some delays between lock syscalls). Fixes: 0fafdc9f ("afs: Fix file locking") Reported-by:Jonathan Billings <jsbillin@umich.edu> Signed-off-by:
David Howells <dhowells@redhat.com>
parent
68ce801f
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