diff options
Diffstat (limited to 'fs/cachefiles/daemon.c')
| -rw-r--r-- | fs/cachefiles/daemon.c | 292 |
1 files changed, 179 insertions, 113 deletions
diff --git a/fs/cachefiles/daemon.c b/fs/cachefiles/daemon.c index 752c1e43416f..aa4efcabb5e3 100644 --- a/fs/cachefiles/daemon.c +++ b/fs/cachefiles/daemon.c @@ -1,7 +1,7 @@ // SPDX-License-Identifier: GPL-2.0-or-later /* Daemon interface * - * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved. + * Copyright (C) 2007, 2021 Red Hat, Inc. All Rights Reserved. * Written by David Howells (dhowells@redhat.com) */ @@ -41,6 +41,8 @@ static int cachefiles_daemon_dir(struct cachefiles_cache *, char *); static int cachefiles_daemon_inuse(struct cachefiles_cache *, char *); static int cachefiles_daemon_secctx(struct cachefiles_cache *, char *); static int cachefiles_daemon_tag(struct cachefiles_cache *, char *); +static int cachefiles_daemon_bind(struct cachefiles_cache *, char *); +static void cachefiles_daemon_unbind(struct cachefiles_cache *); static unsigned long cachefiles_open; @@ -73,12 +75,15 @@ static const struct cachefiles_daemon_cmd cachefiles_daemon_cmds[] = { { "inuse", cachefiles_daemon_inuse }, { "secctx", cachefiles_daemon_secctx }, { "tag", cachefiles_daemon_tag }, +#ifdef CONFIG_CACHEFILES_ONDEMAND + { "copen", cachefiles_ondemand_copen }, +#endif { "", NULL } }; /* - * do various checks + * Prepare a cache for caching. */ static int cachefiles_daemon_open(struct inode *inode, struct file *file) { @@ -102,9 +107,13 @@ static int cachefiles_daemon_open(struct inode *inode, struct file *file) } mutex_init(&cache->daemon_mutex); - cache->active_nodes = RB_ROOT; - rwlock_init(&cache->active_lock); init_waitqueue_head(&cache->daemon_pollwq); + INIT_LIST_HEAD(&cache->volumes); + INIT_LIST_HEAD(&cache->object_list); + spin_lock_init(&cache->object_list_lock); + refcount_set(&cache->unbind_pincount, 1); + xa_init_flags(&cache->reqs, XA_FLAGS_ALLOC); + xa_init_flags(&cache->ondemand_ids, XA_FLAGS_ALLOC1); /* set default caching limits * - limit at 1% free space and/or free files @@ -123,8 +132,55 @@ static int cachefiles_daemon_open(struct inode *inode, struct file *file) return 0; } +static void cachefiles_flush_reqs(struct cachefiles_cache *cache) +{ + struct xarray *xa = &cache->reqs; + struct cachefiles_req *req; + unsigned long index; + + /* + * Make sure the following two operations won't be reordered. + * 1) set CACHEFILES_DEAD bit + * 2) flush requests in the xarray + * Otherwise the request may be enqueued after xarray has been + * flushed, leaving the orphan request never being completed. + * + * CPU 1 CPU 2 + * ===== ===== + * flush requests in the xarray + * test CACHEFILES_DEAD bit + * enqueue the request + * set CACHEFILES_DEAD bit + */ + smp_mb(); + + xa_lock(xa); + xa_for_each(xa, index, req) { + req->error = -EIO; + complete(&req->done); + } + xa_unlock(xa); + + xa_destroy(&cache->reqs); + xa_destroy(&cache->ondemand_ids); +} + +void cachefiles_put_unbind_pincount(struct cachefiles_cache *cache) +{ + if (refcount_dec_and_test(&cache->unbind_pincount)) { + cachefiles_daemon_unbind(cache); + cachefiles_open = 0; + kfree(cache); + } +} + +void cachefiles_get_unbind_pincount(struct cachefiles_cache *cache) +{ + refcount_inc(&cache->unbind_pincount); +} + /* - * release a cache + * Release a cache. */ static int cachefiles_daemon_release(struct inode *inode, struct file *file) { @@ -136,40 +192,29 @@ static int cachefiles_daemon_release(struct inode *inode, struct file *file) set_bit(CACHEFILES_DEAD, &cache->flags); - cachefiles_daemon_unbind(cache); - - ASSERT(!cache->active_nodes.rb_node); + if (cachefiles_in_ondemand_mode(cache)) + cachefiles_flush_reqs(cache); /* clean up the control file interface */ cache->cachefilesd = NULL; file->private_data = NULL; - cachefiles_open = 0; - kfree(cache); + cachefiles_put_unbind_pincount(cache); _leave(""); return 0; } -/* - * read the cache state - */ -static ssize_t cachefiles_daemon_read(struct file *file, char __user *_buffer, - size_t buflen, loff_t *pos) +static ssize_t cachefiles_do_daemon_read(struct cachefiles_cache *cache, + char __user *_buffer, size_t buflen) { - struct cachefiles_cache *cache = file->private_data; unsigned long long b_released; unsigned f_released; char buffer[256]; int n; - //_enter(",,%zu,", buflen); - - if (!test_bit(CACHEFILES_READY, &cache->flags)) - return 0; - /* check how much space the cache has */ - cachefiles_has_space(cache, 0, 0); + cachefiles_has_space(cache, 0, 0, cachefiles_has_space_check); /* summarise */ f_released = atomic_xchg(&cache->f_released, 0); @@ -206,7 +251,26 @@ static ssize_t cachefiles_daemon_read(struct file *file, char __user *_buffer, } /* - * command the cache + * Read the cache state. + */ +static ssize_t cachefiles_daemon_read(struct file *file, char __user *_buffer, + size_t buflen, loff_t *pos) +{ + struct cachefiles_cache *cache = file->private_data; + + //_enter(",,%zu,", buflen); + + if (!test_bit(CACHEFILES_READY, &cache->flags)) + return 0; + + if (cachefiles_in_ondemand_mode(cache)) + return cachefiles_ondemand_daemon_read(cache, _buffer, buflen); + else + return cachefiles_do_daemon_read(cache, _buffer, buflen); +} + +/* + * Take a command from cachefilesd, parse it and act on it. */ static ssize_t cachefiles_daemon_write(struct file *file, const char __user *_data, @@ -225,7 +289,7 @@ static ssize_t cachefiles_daemon_write(struct file *file, if (test_bit(CACHEFILES_DEAD, &cache->flags)) return -EIO; - if (datalen < 0 || datalen > PAGE_SIZE - 1) + if (datalen > PAGE_SIZE - 1) return -EOPNOTSUPP; /* drag the command string into the kernel so we can parse it */ @@ -284,7 +348,7 @@ found_command: } /* - * poll for culling state + * Poll for culling state * - use EPOLLOUT to indicate culling state */ static __poll_t cachefiles_daemon_poll(struct file *file, @@ -296,8 +360,13 @@ static __poll_t cachefiles_daemon_poll(struct file *file, poll_wait(file, &cache->daemon_pollwq, poll); mask = 0; - if (test_bit(CACHEFILES_STATE_CHANGED, &cache->flags)) - mask |= EPOLLIN; + if (cachefiles_in_ondemand_mode(cache)) { + if (!xa_empty(&cache->reqs)) + mask |= EPOLLIN; + } else { + if (test_bit(CACHEFILES_STATE_CHANGED, &cache->flags)) + mask |= EPOLLIN; + } if (test_bit(CACHEFILES_CULLING, &cache->flags)) mask |= EPOLLOUT; @@ -306,7 +375,7 @@ static __poll_t cachefiles_daemon_poll(struct file *file, } /* - * give a range error for cache space constraints + * Give a range error for cache space constraints * - can be tail-called */ static int cachefiles_daemon_range_error(struct cachefiles_cache *cache, @@ -318,7 +387,7 @@ static int cachefiles_daemon_range_error(struct cachefiles_cache *cache, } /* - * set the percentage of files at which to stop culling + * Set the percentage of files at which to stop culling * - command: "frun <N>%" */ static int cachefiles_daemon_frun(struct cachefiles_cache *cache, char *args) @@ -342,7 +411,7 @@ static int cachefiles_daemon_frun(struct cachefiles_cache *cache, char *args) } /* - * set the percentage of files at which to start culling + * Set the percentage of files at which to start culling * - command: "fcull <N>%" */ static int cachefiles_daemon_fcull(struct cachefiles_cache *cache, char *args) @@ -366,7 +435,7 @@ static int cachefiles_daemon_fcull(struct cachefiles_cache *cache, char *args) } /* - * set the percentage of files at which to stop allocating + * Set the percentage of files at which to stop allocating * - command: "fstop <N>%" */ static int cachefiles_daemon_fstop(struct cachefiles_cache *cache, char *args) @@ -382,7 +451,7 @@ static int cachefiles_daemon_fstop(struct cachefiles_cache *cache, char *args) if (args[0] != '%' || args[1] != '\0') return -EINVAL; - if (fstop < 0 || fstop >= cache->fcull_percent) + if (fstop >= cache->fcull_percent) return cachefiles_daemon_range_error(cache, args); cache->fstop_percent = fstop; @@ -390,7 +459,7 @@ static int cachefiles_daemon_fstop(struct cachefiles_cache *cache, char *args) } /* - * set the percentage of blocks at which to stop culling + * Set the percentage of blocks at which to stop culling * - command: "brun <N>%" */ static int cachefiles_daemon_brun(struct cachefiles_cache *cache, char *args) @@ -414,7 +483,7 @@ static int cachefiles_daemon_brun(struct cachefiles_cache *cache, char *args) } /* - * set the percentage of blocks at which to start culling + * Set the percentage of blocks at which to start culling * - command: "bcull <N>%" */ static int cachefiles_daemon_bcull(struct cachefiles_cache *cache, char *args) @@ -438,7 +507,7 @@ static int cachefiles_daemon_bcull(struct cachefiles_cache *cache, char *args) } /* - * set the percentage of blocks at which to stop allocating + * Set the percentage of blocks at which to stop allocating * - command: "bstop <N>%" */ static int cachefiles_daemon_bstop(struct cachefiles_cache *cache, char *args) @@ -454,7 +523,7 @@ static int cachefiles_daemon_bstop(struct cachefiles_cache *cache, char *args) if (args[0] != '%' || args[1] != '\0') return -EINVAL; - if (bstop < 0 || bstop >= cache->bcull_percent) + if (bstop >= cache->bcull_percent) return cachefiles_daemon_range_error(cache, args); cache->bstop_percent = bstop; @@ -462,7 +531,7 @@ static int cachefiles_daemon_bstop(struct cachefiles_cache *cache, char *args) } /* - * set the cache directory + * Set the cache directory * - command: "dir <name>" */ static int cachefiles_daemon_dir(struct cachefiles_cache *cache, char *args) @@ -490,7 +559,7 @@ static int cachefiles_daemon_dir(struct cachefiles_cache *cache, char *args) } /* - * set the cache security context + * Set the cache security context * - command: "secctx <ctx>" */ static int cachefiles_daemon_secctx(struct cachefiles_cache *cache, char *args) @@ -518,7 +587,7 @@ static int cachefiles_daemon_secctx(struct cachefiles_cache *cache, char *args) } /* - * set the cache tag + * Set the cache tag * - command: "tag <name>" */ static int cachefiles_daemon_tag(struct cachefiles_cache *cache, char *args) @@ -544,7 +613,7 @@ static int cachefiles_daemon_tag(struct cachefiles_cache *cache, char *args) } /* - * request a node in the cache be culled from the current working directory + * Request a node in the cache be culled from the current working directory * - command: "cull <name>" */ static int cachefiles_daemon_cull(struct cachefiles_cache *cache, char *args) @@ -568,7 +637,6 @@ static int cachefiles_daemon_cull(struct cachefiles_cache *cache, char *args) return -EIO; } - /* extract the directory dentry from the cwd */ get_fs_pwd(current->fs, &path); if (!d_can_lookup(path.dentry)) @@ -593,7 +661,7 @@ inval: } /* - * set debugging mode + * Set debugging mode * - command: "debug <mask>" */ static int cachefiles_daemon_debug(struct cachefiles_cache *cache, char *args) @@ -616,7 +684,7 @@ inval: } /* - * find out whether an object in the current working directory is in use or not + * Find out whether an object in the current working directory is in use or not * - command: "inuse <name>" */ static int cachefiles_daemon_inuse(struct cachefiles_cache *cache, char *args) @@ -640,7 +708,6 @@ static int cachefiles_daemon_inuse(struct cachefiles_cache *cache, char *args) return -EIO; } - /* extract the directory dentry from the cwd */ get_fs_pwd(current->fs, &path); if (!d_can_lookup(path.dentry)) @@ -665,84 +732,83 @@ inval: } /* - * see if we have space for a number of pages and/or a number of files in the - * cache + * Bind a directory as a cache */ -int cachefiles_has_space(struct cachefiles_cache *cache, - unsigned fnr, unsigned bnr) +static int cachefiles_daemon_bind(struct cachefiles_cache *cache, char *args) { - struct kstatfs stats; - struct path path = { - .mnt = cache->mnt, - .dentry = cache->mnt->mnt_root, - }; - int ret; + _enter("{%u,%u,%u,%u,%u,%u},%s", + cache->frun_percent, + cache->fcull_percent, + cache->fstop_percent, + cache->brun_percent, + cache->bcull_percent, + cache->bstop_percent, + args); + + if (cache->fstop_percent >= cache->fcull_percent || + cache->fcull_percent >= cache->frun_percent || + cache->frun_percent >= 100) + return -ERANGE; + + if (cache->bstop_percent >= cache->bcull_percent || + cache->bcull_percent >= cache->brun_percent || + cache->brun_percent >= 100) + return -ERANGE; + + if (!cache->rootdirname) { + pr_err("No cache directory specified\n"); + return -EINVAL; + } - //_enter("{%llu,%llu,%llu,%llu,%llu,%llu},%u,%u", - // (unsigned long long) cache->frun, - // (unsigned long long) cache->fcull, - // (unsigned long long) cache->fstop, - // (unsigned long long) cache->brun, - // (unsigned long long) cache->bcull, - // (unsigned long long) cache->bstop, - // fnr, bnr); - - /* find out how many pages of blockdev are available */ - memset(&stats, 0, sizeof(stats)); - - ret = vfs_statfs(&path, &stats); - if (ret < 0) { - if (ret == -EIO) - cachefiles_io_error(cache, "statfs failed"); - _leave(" = %d", ret); - return ret; + /* Don't permit already bound caches to be re-bound */ + if (test_bit(CACHEFILES_READY, &cache->flags)) { + pr_err("Cache already bound\n"); + return -EBUSY; } - stats.f_bavail >>= cache->bshift; + if (IS_ENABLED(CONFIG_CACHEFILES_ONDEMAND)) { + if (!strcmp(args, "ondemand")) { + set_bit(CACHEFILES_ONDEMAND_MODE, &cache->flags); + } else if (*args) { + pr_err("Invalid argument to the 'bind' command\n"); + return -EINVAL; + } + } else if (*args) { + pr_err("'bind' command doesn't take an argument\n"); + return -EINVAL; + } - //_debug("avail %llu,%llu", - // (unsigned long long) stats.f_ffree, - // (unsigned long long) stats.f_bavail); + /* Make sure we have copies of the tag string */ + if (!cache->tag) { + /* + * The tag string is released by the fops->release() + * function, so we don't release it on error here + */ + cache->tag = kstrdup("CacheFiles", GFP_KERNEL); + if (!cache->tag) + return -ENOMEM; + } - /* see if there is sufficient space */ - if (stats.f_ffree > fnr) - stats.f_ffree -= fnr; - else - stats.f_ffree = 0; + return cachefiles_add_cache(cache); +} - if (stats.f_bavail > bnr) - stats.f_bavail -= bnr; - else - stats.f_bavail = 0; - - ret = -ENOBUFS; - if (stats.f_ffree < cache->fstop || - stats.f_bavail < cache->bstop) - goto begin_cull; - - ret = 0; - if (stats.f_ffree < cache->fcull || - stats.f_bavail < cache->bcull) - goto begin_cull; - - if (test_bit(CACHEFILES_CULLING, &cache->flags) && - stats.f_ffree >= cache->frun && - stats.f_bavail >= cache->brun && - test_and_clear_bit(CACHEFILES_CULLING, &cache->flags) - ) { - _debug("cease culling"); - cachefiles_state_changed(cache); - } +/* + * Unbind a cache. + */ +static void cachefiles_daemon_unbind(struct cachefiles_cache *cache) +{ + _enter(""); - //_leave(" = 0"); - return 0; + if (test_bit(CACHEFILES_READY, &cache->flags)) + cachefiles_withdraw_cache(cache); -begin_cull: - if (!test_and_set_bit(CACHEFILES_CULLING, &cache->flags)) { - _debug("### CULL CACHE ###"); - cachefiles_state_changed(cache); - } + cachefiles_put_directory(cache->graveyard); + cachefiles_put_directory(cache->store); + mntput(cache->mnt); - _leave(" = %d", ret); - return ret; + kfree(cache->rootdirname); + kfree(cache->secctx); + kfree(cache->tag); + + _leave(""); } |