diff options
Diffstat (limited to 'fs/cachefiles/daemon.c')
| -rw-r--r-- | fs/cachefiles/daemon.c | 393 |
1 files changed, 234 insertions, 159 deletions
diff --git a/fs/cachefiles/daemon.c b/fs/cachefiles/daemon.c index 0a1467b15516..1806bff8e59b 100644 --- a/fs/cachefiles/daemon.c +++ b/fs/cachefiles/daemon.c @@ -1,12 +1,8 @@ +// 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) - * - * This program is free software; you can redistribute it and/or - * modify it under the terms of the GNU General Public Licence - * as published by the Free Software Foundation; either version - * 2 of the Licence, or (at your option) any later version. */ #include <linux/module.h> @@ -19,6 +15,7 @@ #include <linux/namei.h> #include <linux/poll.h> #include <linux/mount.h> +#include <linux/security.h> #include <linux/statfs.h> #include <linux/ctype.h> #include <linux/string.h> @@ -31,7 +28,7 @@ static ssize_t cachefiles_daemon_read(struct file *, char __user *, size_t, loff_t *); static ssize_t cachefiles_daemon_write(struct file *, const char __user *, size_t, loff_t *); -static unsigned int cachefiles_daemon_poll(struct file *, +static __poll_t cachefiles_daemon_poll(struct file *, struct poll_table_struct *); static int cachefiles_daemon_frun(struct cachefiles_cache *, char *); static int cachefiles_daemon_fcull(struct cachefiles_cache *, char *); @@ -45,6 +42,8 @@ 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; @@ -77,12 +76,16 @@ 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 }, + { "restore", cachefiles_ondemand_restore }, +#endif { "", NULL } }; /* - * do various checks + * Prepare a cache for caching. */ static int cachefiles_daemon_open(struct inode *inode, struct file *file) { @@ -106,9 +109,13 @@ 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 @@ -127,8 +134,56 @@ static int cachefiles_daemon_open(struct inode *inode, struct file *file) return 0; } +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_erase(xa, index); + } + 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) { @@ -140,40 +195,33 @@ 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); + b_released = atomic_long_xchg(&cache->b_released, 0); clear_bit(CACHEFILES_STATE_CHANGED, &cache->flags); n = snprintf(buffer, sizeof(buffer), @@ -183,15 +231,18 @@ static ssize_t cachefiles_daemon_read(struct file *file, char __user *_buffer, " fstop=%llx" " brun=%llx" " bcull=%llx" - " bstop=%llx", + " bstop=%llx" + " freleased=%x" + " breleased=%llx", test_bit(CACHEFILES_CULLING, &cache->flags) ? '1' : '0', (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 - ); + (unsigned long long) cache->bstop, + f_released, + b_released); if (n > buflen) return -EMSGSIZE; @@ -203,7 +254,26 @@ 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, @@ -222,19 +292,13 @@ 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 */ - data = kmalloc(datalen + 1, GFP_KERNEL); - if (!data) - return -ENOMEM; - - ret = -EFAULT; - if (copy_from_user(data, _data, datalen) != 0) - goto error; - - data[datalen] = '\0'; + data = memdup_user_nul(_data, datalen); + if (IS_ERR(data)) + return PTR_ERR(data); ret = -EINVAL; if (memchr(data, '\0', datalen)) @@ -287,42 +351,56 @@ found_command: } /* - * poll for culling state - * - use POLLOUT to indicate culling state + * Poll for culling state + * - use EPOLLOUT to indicate culling state */ -static unsigned int cachefiles_daemon_poll(struct file *file, +static __poll_t cachefiles_daemon_poll(struct file *file, struct poll_table_struct *poll) { struct cachefiles_cache *cache = file->private_data; - unsigned int mask; + XA_STATE(xas, &cache->reqs, 0); + struct cachefiles_req *req; + __poll_t mask; poll_wait(file, &cache->daemon_pollwq, poll); mask = 0; - if (test_bit(CACHEFILES_STATE_CHANGED, &cache->flags)) - mask |= POLLIN; + if (cachefiles_in_ondemand_mode(cache)) { + if (!xa_empty(&cache->reqs)) { + xas_lock(&xas); + xas_for_each_marked(&xas, req, ULONG_MAX, CACHEFILES_REQ_NEW) { + if (!cachefiles_ondemand_is_reopening_read(req)) { + mask |= EPOLLIN; + break; + } + } + xas_unlock(&xas); + } + } else { + if (test_bit(CACHEFILES_STATE_CHANGED, &cache->flags)) + mask |= EPOLLIN; + } if (test_bit(CACHEFILES_CULLING, &cache->flags)) - mask |= POLLOUT; + mask |= EPOLLOUT; return mask; } /* - * 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, char *args) { - kerror("Free space limits must be in range" - " 0%%<=stop<cull<run<100%%"); + pr_err("Free space limits must be in range 0%%<=stop<cull<run<100%%\n"); return -EINVAL; } /* - * 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) @@ -346,7 +424,7 @@ 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) @@ -370,7 +448,7 @@ 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) @@ -386,7 +464,7 @@ 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; @@ -394,7 +472,7 @@ 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) @@ -418,7 +496,7 @@ 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) @@ -442,7 +520,7 @@ 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) @@ -458,7 +536,7 @@ 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; @@ -466,7 +544,7 @@ 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) @@ -476,12 +554,12 @@ static int cachefiles_daemon_dir(struct cachefiles_cache *cache, char *args) _enter(",%s", args); if (!*args) { - kerror("Empty directory specified"); + pr_err("Empty directory specified\n"); return -EINVAL; } if (cache->rootdirname) { - kerror("Second cache directory specified"); + pr_err("Second cache directory specified\n"); return -EEXIST; } @@ -494,35 +572,35 @@ 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) { - char *secctx; + int err; _enter(",%s", args); if (!*args) { - kerror("Empty security context specified"); + pr_err("Empty security context specified\n"); return -EINVAL; } - if (cache->secctx) { - kerror("Second security context specified"); + if (cache->have_secid) { + pr_err("Second security context specified\n"); return -EINVAL; } - secctx = kstrdup(args, GFP_KERNEL); - if (!secctx) - return -ENOMEM; + err = security_secctx_to_secid(args, strlen(args), &cache->secid); + if (err) + return err; - cache->secctx = secctx; + cache->have_secid = true; return 0; } /* - * set the cache tag + * Set the cache tag * - command: "tag <name>" */ static int cachefiles_daemon_tag(struct cachefiles_cache *cache, char *args) @@ -532,7 +610,7 @@ static int cachefiles_daemon_tag(struct cachefiles_cache *cache, char *args) _enter(",%s", args); if (!*args) { - kerror("Empty tag specified"); + pr_err("Empty tag specified\n"); return -EINVAL; } @@ -548,7 +626,7 @@ 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) @@ -563,19 +641,18 @@ static int cachefiles_daemon_cull(struct cachefiles_cache *cache, char *args) goto inval; if (!test_bit(CACHEFILES_READY, &cache->flags)) { - kerror("cull applied to unready cache"); + pr_err("cull applied to unready cache\n"); return -EIO; } if (test_bit(CACHEFILES_DEAD, &cache->flags)) { - kerror("cull applied to dead cache"); + pr_err("cull applied to dead cache\n"); return -EIO; } - /* extract the directory dentry from the cwd */ get_fs_pwd(current->fs, &path); - if (!S_ISDIR(path.dentry->d_inode->i_mode)) + if (!d_can_lookup(path.dentry)) goto notdir; cachefiles_begin_secure(cache, &saved_cred); @@ -588,16 +665,16 @@ static int cachefiles_daemon_cull(struct cachefiles_cache *cache, char *args) notdir: path_put(&path); - kerror("cull command requires dirfd to be a directory"); + pr_err("cull command requires dirfd to be a directory\n"); return -ENOTDIR; inval: - kerror("cull command requires dirfd and filename"); + pr_err("cull command requires dirfd and filename\n"); return -EINVAL; } /* - * set debugging mode + * Set debugging mode * - command: "debug <mask>" */ static int cachefiles_daemon_debug(struct cachefiles_cache *cache, char *args) @@ -615,12 +692,12 @@ static int cachefiles_daemon_debug(struct cachefiles_cache *cache, char *args) return 0; inval: - kerror("debug command requires mask"); + pr_err("debug command requires mask\n"); return -EINVAL; } /* - * 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) @@ -635,19 +712,18 @@ static int cachefiles_daemon_inuse(struct cachefiles_cache *cache, char *args) goto inval; if (!test_bit(CACHEFILES_READY, &cache->flags)) { - kerror("inuse applied to unready cache"); + pr_err("inuse applied to unready cache\n"); return -EIO; } if (test_bit(CACHEFILES_DEAD, &cache->flags)) { - kerror("inuse applied to dead cache"); + pr_err("inuse applied to dead cache\n"); return -EIO; } - /* extract the directory dentry from the cwd */ get_fs_pwd(current->fs, &path); - if (!S_ISDIR(path.dentry->d_inode->i_mode)) + if (!d_can_lookup(path.dentry)) goto notdir; cachefiles_begin_secure(cache, &saved_cred); @@ -660,93 +736,92 @@ static int cachefiles_daemon_inuse(struct cachefiles_cache *cache, char *args) notdir: path_put(&path); - kerror("inuse command requires dirfd to be a directory"); + pr_err("inuse command requires dirfd to be a directory\n"); return -ENOTDIR; inval: - kerror("inuse command requires dirfd and filename"); + pr_err("inuse command requires dirfd and filename\n"); return -EINVAL; } /* - * 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; + } + + /* 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; + } - //_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; + 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; } - stats.f_bavail >>= cache->bshift; + /* 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; + } - //_debug("avail %llu,%llu", - // (unsigned long long) stats.f_ffree, - // (unsigned long long) stats.f_bavail); + return cachefiles_add_cache(cache); +} - /* see if there is sufficient space */ - if (stats.f_ffree > fnr) - stats.f_ffree -= fnr; - else - stats.f_ffree = 0; +/* + * Unbind a cache. + */ +static void cachefiles_daemon_unbind(struct cachefiles_cache *cache) +{ + _enter(""); - 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); - } + if (test_bit(CACHEFILES_READY, &cache->flags)) + cachefiles_withdraw_cache(cache); - //_leave(" = 0"); - return 0; + cachefiles_put_directory(cache->graveyard); + cachefiles_put_directory(cache->store); + mntput(cache->mnt); + put_cred(cache->cache_cred); -begin_cull: - if (!test_and_set_bit(CACHEFILES_CULLING, &cache->flags)) { - _debug("### CULL CACHE ###"); - cachefiles_state_changed(cache); - } + kfree(cache->rootdirname); + kfree(cache->tag); - _leave(" = %d", ret); - return ret; + _leave(""); } |