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| author |   David Howells <dhowells@redhat.com> | 2012-12-20 21:52:36 +0000 |
|---|---|---|
| committer | David Howells <dhowells@redhat.com> | 2012-12-20 22:06:08 +0000 |
| commit | 9dc8d9bfe4415efb61a5e9390706b8a3bffef329 (patch) | |
| tree | 2534486c442b7889a761d894f3bd4dd0403608ca /fs/cachefiles/rdwr.c | |
| parent | VFS: Make more complete truncate operation available to CacheFiles (diff) | |
| download | wireguard-linux-9dc8d9bfe4415efb61a5e9390706b8a3bffef329.tar.xz wireguard-linux-9dc8d9bfe4415efb61a5e9390706b8a3bffef329.zip | |
CacheFiles: Implement invalidation
Implement invalidation for CacheFiles. This is in two parts:
(1) Provide an invalidation method (which just truncates the backing file).
(2) Abort attempts to copy anything read from the backing file whilst
invalidation is in progress.
Question: CacheFiles uses truncation in a couple of places. It has been using
notify_change() rather than sys_truncate() or something similar. This means
it bypasses a bunch of checks and suchlike that it possibly should be making
(security, file locking, lease breaking, vfsmount write). Should it be using
vfs_truncate() as added by a preceding patch or should it use notify_write()
and assume that anyone poking around in the cache files on disk gets
everything they deserve?
Signed-off-by: David Howells <dhowells@redhat.com>
Diffstat (limited to 'fs/cachefiles/rdwr.c')
| -rw-r--r-- | fs/cachefiles/rdwr.c | 5 |
1 files changed, 4 insertions, 1 deletions
diff --git a/fs/cachefiles/rdwr.c b/fs/cachefiles/rdwr.c index 93a0815e0498..2c994885520a 100644 --- a/fs/cachefiles/rdwr.c +++ b/fs/cachefiles/rdwr.c @@ -174,7 +174,10 @@ static void cachefiles_read_copier(struct fscache_operation *_op) _debug("- copy {%lu}", monitor->back_page->index); recheck: - if (PageUptodate(monitor->back_page)) { + if (test_bit(FSCACHE_COOKIE_INVALIDATING, + &object->fscache.cookie->flags)) { + error = -ESTALE; + } else if (PageUptodate(monitor->back_page)) { copy_highpage(monitor->netfs_page, monitor->back_page); fscache_mark_page_cached(monitor->op, monitor->netfs_page); |