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authorDavid Howells <dhowells@redhat.com>2012-12-20 21:52:36 +0000
committerDavid Howells <dhowells@redhat.com>2012-12-20 22:06:08 +0000
commit9dc8d9bfe4415efb61a5e9390706b8a3bffef329 (patch)
tree2534486c442b7889a761d894f3bd4dd0403608ca /fs/cachefiles/rdwr.c
parenta02de9608595c8ef649ef03ae735b0b45e3d4396 (diff)
downloadlinux-9dc8d9bfe4415efb61a5e9390706b8a3bffef329.tar.bz2
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.c5
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);