From 1f08c925e7a38002bde509e66f6f891468848511 Mon Sep 17 00:00:00 2001 From: David Howells Date: Thu, 21 Oct 2021 08:50:10 +0100 Subject: cachefiles: Implement backing file wrangling Implement the wrangling of backing files, including the following pieces: (1) Lookup and creation of a file on disk, using a tmpfile if the file isn't yet present. The file is then opened, sized for DIO and the file handle is attached to the cachefiles_object struct. The inode is marked to indicate that it's in use by a kernel service. (2) Invalidation of an object, creating a tmpfile and switching the file pointer in the cachefiles object. (3) Committing a file to disk, including setting the coherency xattr on it and, if necessary, creating a hard link to it. Note that this would be a good place to use Omar Sandoval's vfs_link() with AT_LINK_REPLACE[1] as I may have to unlink an old file before I can link a tmpfile into place. (4) Withdrawal of open objects when a cache is being withdrawn or a cookie is relinquished. This involves committing or discarding the file. Changes ======= ver #2: - Fix logging of wrong error[1]. Signed-off-by: David Howells Reviewed-by: Jeff Layton cc: linux-cachefs@redhat.com Link: https://lore.kernel.org/r/20211203094950.GA2480@kili/ [1] Link: https://lore.kernel.org/r/163819644097.215744.4505389616742411239.stgit@warthog.procyon.org.uk/ # v1 Link: https://lore.kernel.org/r/163906949512.143852.14222856795032602080.stgit@warthog.procyon.org.uk/ # v2 Link: https://lore.kernel.org/r/163967158526.1823006.17482695321424642675.stgit@warthog.procyon.org.uk/ # v3 Link: https://lore.kernel.org/r/164021557060.640689.16373541458119269871.stgit@warthog.procyon.org.uk/ # v4 --- fs/cachefiles/daemon.c | 1 + 1 file changed, 1 insertion(+) (limited to 'fs/cachefiles/daemon.c') diff --git a/fs/cachefiles/daemon.c b/fs/cachefiles/daemon.c index 985c3f3e6767..61e8740d01be 100644 --- a/fs/cachefiles/daemon.c +++ b/fs/cachefiles/daemon.c @@ -106,6 +106,7 @@ static int cachefiles_daemon_open(struct inode *inode, struct file *file) mutex_init(&cache->daemon_mutex); init_waitqueue_head(&cache->daemon_pollwq); INIT_LIST_HEAD(&cache->volumes); + INIT_LIST_HEAD(&cache->object_list); spin_lock_init(&cache->object_list_lock); /* set default caching limits -- cgit v1.2.3