From 3003bbd0697b659944237f3459489cb596ba196c Mon Sep 17 00:00:00 2001 From: David Howells Date: Thu, 6 Feb 2020 14:22:29 +0000 Subject: afs: Use the netfs_write_begin() helper Make AFS use the new netfs_write_begin() helper to do the pre-reading required before the write. If successful, the helper returns with the required page filled in and locked. It may read more than just one page, expanding the read to meet cache granularity requirements as necessary. Note: A more advanced version of this could be made that does generic_perform_write() for a whole cache granule. This would make it easier to avoid doing the download/read for the data to be overwritten. Signed-off-by: David Howells Tested-By: Marc Dionne cc: linux-afs@lists.infradead.org cc: linux-cachefs@redhat.com cc: linux-fsdevel@vger.kernel.org Link: https://lore.kernel.org/r/160588546422.3465195.1546354372589291098.stgit@warthog.procyon.org.uk/ # rfc Link: https://lore.kernel.org/r/161539563244.286939.16537296241609909980.stgit@warthog.procyon.org.uk/ # v4 Link: https://lore.kernel.org/r/161653819291.2770958.406013201547420544.stgit@warthog.procyon.org.uk/ # v5 Link: https://lore.kernel.org/r/161789102743.6155.17396591236631761195.stgit@warthog.procyon.org.uk/ # v6 --- fs/afs/file.c | 19 ++++++++++++++++++- 1 file changed, 18 insertions(+), 1 deletion(-) (limited to 'fs/afs/file.c') diff --git a/fs/afs/file.c b/fs/afs/file.c index 10c6eaaac2cc..db035ae2a134 100644 --- a/fs/afs/file.c +++ b/fs/afs/file.c @@ -333,6 +333,13 @@ static void afs_init_rreq(struct netfs_read_request *rreq, struct file *file) rreq->netfs_priv = key_get(afs_file_key(file)); } +static bool afs_is_cache_enabled(struct inode *inode) +{ + struct fscache_cookie *cookie = afs_vnode_cache(AFS_FS_I(inode)); + + return fscache_cookie_enabled(cookie) && !hlist_empty(&cookie->backing_objects); +} + static int afs_begin_cache_operation(struct netfs_read_request *rreq) { struct afs_vnode *vnode = AFS_FS_I(rreq->inode); @@ -340,14 +347,24 @@ static int afs_begin_cache_operation(struct netfs_read_request *rreq) return fscache_begin_read_operation(rreq, afs_vnode_cache(vnode)); } +static int afs_check_write_begin(struct file *file, loff_t pos, unsigned len, + struct page *page, void **_fsdata) +{ + struct afs_vnode *vnode = AFS_FS_I(file_inode(file)); + + return test_bit(AFS_VNODE_DELETED, &vnode->flags) ? -ESTALE : 0; +} + static void afs_priv_cleanup(struct address_space *mapping, void *netfs_priv) { key_put(netfs_priv); } -static const struct netfs_read_request_ops afs_req_ops = { +const struct netfs_read_request_ops afs_req_ops = { .init_rreq = afs_init_rreq, + .is_cache_enabled = afs_is_cache_enabled, .begin_cache_operation = afs_begin_cache_operation, + .check_write_begin = afs_check_write_begin, .issue_op = afs_req_issue_op, .cleanup = afs_priv_cleanup, }; -- cgit v1.2.3