#include "internal.h"
/*
+ * Bring a cache online.
+ */
+int cachefiles_add_cache(struct cachefiles_cache *cache)
+{
+ struct fscache_cache *cache_cookie;
+ struct path path;
+ struct kstatfs stats;
+ struct dentry *graveyard, *cachedir, *root;
+ const struct cred *saved_cred;
+ int ret;
+
+ _enter("");
+
+ cache_cookie = fscache_acquire_cache(cache->tag);
+ if (IS_ERR(cache_cookie))
+ return PTR_ERR(cache_cookie);
+
+ /* we want to work under the module's security ID */
+ ret = cachefiles_get_security_ID(cache);
+ if (ret < 0)
+ goto error_getsec;
+
+ cachefiles_begin_secure(cache, &saved_cred);
+
+ /* look up the directory at the root of the cache */
+ ret = kern_path(cache->rootdirname, LOOKUP_DIRECTORY, &path);
+ if (ret < 0)
+ goto error_open_root;
+
+ cache->mnt = path.mnt;
+ root = path.dentry;
+
+ ret = -EINVAL;
+ if (mnt_user_ns(path.mnt) != &init_user_ns) {
+ pr_warn("File cache on idmapped mounts not supported");
+ goto error_unsupported;
+ }
+
+ /* check parameters */
+ ret = -EOPNOTSUPP;
+ if (d_is_negative(root) ||
+ !d_backing_inode(root)->i_op->lookup ||
+ !d_backing_inode(root)->i_op->mkdir ||
+ !(d_backing_inode(root)->i_opflags & IOP_XATTR) ||
+ !root->d_sb->s_op->statfs ||
+ !root->d_sb->s_op->sync_fs ||
+ root->d_sb->s_blocksize > PAGE_SIZE)
+ goto error_unsupported;
+
+ ret = -EROFS;
+ if (sb_rdonly(root->d_sb))
+ goto error_unsupported;
+
+ /* determine the security of the on-disk cache as this governs
+ * security ID of files we create */
+ ret = cachefiles_determine_cache_security(cache, root, &saved_cred);
+ if (ret < 0)
+ goto error_unsupported;
+
+ /* get the cache size and blocksize */
+ ret = vfs_statfs(&path, &stats);
+ if (ret < 0)
+ goto error_unsupported;
+
+ ret = -ERANGE;
+ if (stats.f_bsize <= 0)
+ goto error_unsupported;
+
+ ret = -EOPNOTSUPP;
+ if (stats.f_bsize > PAGE_SIZE)
+ goto error_unsupported;
+
+ cache->bsize = stats.f_bsize;
+ cache->bshift = 0;
+ if (stats.f_bsize < PAGE_SIZE)
+ cache->bshift = PAGE_SHIFT - ilog2(stats.f_bsize);
+
+ _debug("blksize %u (shift %u)",
+ cache->bsize, cache->bshift);
+
+ _debug("size %llu, avail %llu",
+ (unsigned long long) stats.f_blocks,
+ (unsigned long long) stats.f_bavail);
+
+ /* set up caching limits */
+ do_div(stats.f_files, 100);
+ cache->fstop = stats.f_files * cache->fstop_percent;
+ cache->fcull = stats.f_files * cache->fcull_percent;
+ cache->frun = stats.f_files * cache->frun_percent;
+
+ _debug("limits {%llu,%llu,%llu} files",
+ (unsigned long long) cache->frun,
+ (unsigned long long) cache->fcull,
+ (unsigned long long) cache->fstop);
+
+ stats.f_blocks >>= cache->bshift;
+ do_div(stats.f_blocks, 100);
+ cache->bstop = stats.f_blocks * cache->bstop_percent;
+ cache->bcull = stats.f_blocks * cache->bcull_percent;
+ cache->brun = stats.f_blocks * cache->brun_percent;
+
+ _debug("limits {%llu,%llu,%llu} blocks",
+ (unsigned long long) cache->brun,
+ (unsigned long long) cache->bcull,
+ (unsigned long long) cache->bstop);
+
+ /* get the cache directory and check its type */
+ cachedir = cachefiles_get_directory(cache, root, "cache", NULL);
+ if (IS_ERR(cachedir)) {
+ ret = PTR_ERR(cachedir);
+ goto error_unsupported;
+ }
+
+ cache->store = cachedir;
+
+ /* get the graveyard directory */
+ graveyard = cachefiles_get_directory(cache, root, "graveyard", NULL);
+ if (IS_ERR(graveyard)) {
+ ret = PTR_ERR(graveyard);
+ goto error_unsupported;
+ }
+
+ cache->graveyard = graveyard;
+ cache->cache = cache_cookie;
+
+ ret = fscache_add_cache(cache_cookie, &cachefiles_cache_ops, cache);
+ if (ret < 0)
+ goto error_add_cache;
+
+ /* done */
+ set_bit(CACHEFILES_READY, &cache->flags);
+ dput(root);
+
+ pr_info("File cache on %s registered\n", cache_cookie->name);
+
+ /* check how much space the cache has */
+ cachefiles_has_space(cache, 0, 0);
+ cachefiles_end_secure(cache, saved_cred);
+ _leave(" = 0 [%px]", cache->cache);
+ return 0;
+
+error_add_cache:
+ cachefiles_put_directory(cache->graveyard);
+ cache->graveyard = NULL;
+error_unsupported:
+ cachefiles_put_directory(cache->store);
+ cache->store = NULL;
+ mntput(cache->mnt);
+ cache->mnt = NULL;
+ dput(root);
+error_open_root:
+ cachefiles_end_secure(cache, saved_cred);
+error_getsec:
+ fscache_relinquish_cache(cache_cookie);
+ cache->cache = NULL;
+ pr_err("Failed to register: %d\n", ret);
+ return ret;
+}
+
+/*
* See if we have space for a number of pages and/or a number of files in the
* cache
*/
_leave(" = %d", ret);
return ret;
}
+
+/*
+ * Sync a cache to backing disk.
+ */
+static void cachefiles_sync_cache(struct cachefiles_cache *cache)
+{
+ const struct cred *saved_cred;
+ int ret;
+
+ _enter("%s", cache->cache->name);
+
+ /* make sure all pages pinned by operations on behalf of the netfs are
+ * written to disc */
+ cachefiles_begin_secure(cache, &saved_cred);
+ down_read(&cache->mnt->mnt_sb->s_umount);
+ ret = sync_filesystem(cache->mnt->mnt_sb);
+ up_read(&cache->mnt->mnt_sb->s_umount);
+ cachefiles_end_secure(cache, saved_cred);
+
+ if (ret == -EIO)
+ cachefiles_io_error(cache,
+ "Attempt to sync backing fs superblock returned error %d",
+ ret);
+}
+
+/*
+ * Withdraw cache objects.
+ */
+void cachefiles_withdraw_cache(struct cachefiles_cache *cache)
+{
+ struct fscache_cache *fscache = cache->cache;
+
+ pr_info("File cache on %s unregistering\n", fscache->name);
+
+ fscache_withdraw_cache(fscache);
+
+ /* we now have to destroy all the active objects pertaining to this
+ * cache - which we do by passing them off to thread pool to be
+ * disposed of */
+ // PLACEHOLDER: Withdraw objects
+ fscache_wait_for_objects(fscache);
+
+ // PLACEHOLDER: Withdraw volume
+ cachefiles_sync_cache(cache);
+ cache->cache = NULL;
+ fscache_relinquish_cache(fscache);
+}
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