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0001 // SPDX-License-Identifier: GPL-2.0-or-later
0002 /* Daemon interface
0003  *
0004  * Copyright (C) 2007, 2021 Red Hat, Inc. All Rights Reserved.
0005  * Written by David Howells (dhowells@redhat.com)
0006  */
0007 
0008 #include <linux/module.h>
0009 #include <linux/init.h>
0010 #include <linux/sched.h>
0011 #include <linux/completion.h>
0012 #include <linux/slab.h>
0013 #include <linux/fs.h>
0014 #include <linux/file.h>
0015 #include <linux/namei.h>
0016 #include <linux/poll.h>
0017 #include <linux/mount.h>
0018 #include <linux/statfs.h>
0019 #include <linux/ctype.h>
0020 #include <linux/string.h>
0021 #include <linux/fs_struct.h>
0022 #include "internal.h"
0023 
0024 static int cachefiles_daemon_open(struct inode *, struct file *);
0025 static int cachefiles_daemon_release(struct inode *, struct file *);
0026 static ssize_t cachefiles_daemon_read(struct file *, char __user *, size_t,
0027                       loff_t *);
0028 static ssize_t cachefiles_daemon_write(struct file *, const char __user *,
0029                        size_t, loff_t *);
0030 static __poll_t cachefiles_daemon_poll(struct file *,
0031                        struct poll_table_struct *);
0032 static int cachefiles_daemon_frun(struct cachefiles_cache *, char *);
0033 static int cachefiles_daemon_fcull(struct cachefiles_cache *, char *);
0034 static int cachefiles_daemon_fstop(struct cachefiles_cache *, char *);
0035 static int cachefiles_daemon_brun(struct cachefiles_cache *, char *);
0036 static int cachefiles_daemon_bcull(struct cachefiles_cache *, char *);
0037 static int cachefiles_daemon_bstop(struct cachefiles_cache *, char *);
0038 static int cachefiles_daemon_cull(struct cachefiles_cache *, char *);
0039 static int cachefiles_daemon_debug(struct cachefiles_cache *, char *);
0040 static int cachefiles_daemon_dir(struct cachefiles_cache *, char *);
0041 static int cachefiles_daemon_inuse(struct cachefiles_cache *, char *);
0042 static int cachefiles_daemon_secctx(struct cachefiles_cache *, char *);
0043 static int cachefiles_daemon_tag(struct cachefiles_cache *, char *);
0044 static int cachefiles_daemon_bind(struct cachefiles_cache *, char *);
0045 static void cachefiles_daemon_unbind(struct cachefiles_cache *);
0046 
0047 static unsigned long cachefiles_open;
0048 
0049 const struct file_operations cachefiles_daemon_fops = {
0050     .owner      = THIS_MODULE,
0051     .open       = cachefiles_daemon_open,
0052     .release    = cachefiles_daemon_release,
0053     .read       = cachefiles_daemon_read,
0054     .write      = cachefiles_daemon_write,
0055     .poll       = cachefiles_daemon_poll,
0056     .llseek     = noop_llseek,
0057 };
0058 
0059 struct cachefiles_daemon_cmd {
0060     char name[8];
0061     int (*handler)(struct cachefiles_cache *cache, char *args);
0062 };
0063 
0064 static const struct cachefiles_daemon_cmd cachefiles_daemon_cmds[] = {
0065     { "bind",   cachefiles_daemon_bind      },
0066     { "brun",   cachefiles_daemon_brun      },
0067     { "bcull",  cachefiles_daemon_bcull     },
0068     { "bstop",  cachefiles_daemon_bstop     },
0069     { "cull",   cachefiles_daemon_cull      },
0070     { "debug",  cachefiles_daemon_debug     },
0071     { "dir",    cachefiles_daemon_dir       },
0072     { "frun",   cachefiles_daemon_frun      },
0073     { "fcull",  cachefiles_daemon_fcull     },
0074     { "fstop",  cachefiles_daemon_fstop     },
0075     { "inuse",  cachefiles_daemon_inuse     },
0076     { "secctx", cachefiles_daemon_secctx    },
0077     { "tag",    cachefiles_daemon_tag       },
0078 #ifdef CONFIG_CACHEFILES_ONDEMAND
0079     { "copen",  cachefiles_ondemand_copen   },
0080 #endif
0081     { "",       NULL                }
0082 };
0083 
0084 
0085 /*
0086  * Prepare a cache for caching.
0087  */
0088 static int cachefiles_daemon_open(struct inode *inode, struct file *file)
0089 {
0090     struct cachefiles_cache *cache;
0091 
0092     _enter("");
0093 
0094     /* only the superuser may do this */
0095     if (!capable(CAP_SYS_ADMIN))
0096         return -EPERM;
0097 
0098     /* the cachefiles device may only be open once at a time */
0099     if (xchg(&cachefiles_open, 1) == 1)
0100         return -EBUSY;
0101 
0102     /* allocate a cache record */
0103     cache = kzalloc(sizeof(struct cachefiles_cache), GFP_KERNEL);
0104     if (!cache) {
0105         cachefiles_open = 0;
0106         return -ENOMEM;
0107     }
0108 
0109     mutex_init(&cache->daemon_mutex);
0110     init_waitqueue_head(&cache->daemon_pollwq);
0111     INIT_LIST_HEAD(&cache->volumes);
0112     INIT_LIST_HEAD(&cache->object_list);
0113     spin_lock_init(&cache->object_list_lock);
0114     refcount_set(&cache->unbind_pincount, 1);
0115     xa_init_flags(&cache->reqs, XA_FLAGS_ALLOC);
0116     xa_init_flags(&cache->ondemand_ids, XA_FLAGS_ALLOC1);
0117 
0118     /* set default caching limits
0119      * - limit at 1% free space and/or free files
0120      * - cull below 5% free space and/or free files
0121      * - cease culling above 7% free space and/or free files
0122      */
0123     cache->frun_percent = 7;
0124     cache->fcull_percent = 5;
0125     cache->fstop_percent = 1;
0126     cache->brun_percent = 7;
0127     cache->bcull_percent = 5;
0128     cache->bstop_percent = 1;
0129 
0130     file->private_data = cache;
0131     cache->cachefilesd = file;
0132     return 0;
0133 }
0134 
0135 static void cachefiles_flush_reqs(struct cachefiles_cache *cache)
0136 {
0137     struct xarray *xa = &cache->reqs;
0138     struct cachefiles_req *req;
0139     unsigned long index;
0140 
0141     /*
0142      * Make sure the following two operations won't be reordered.
0143      *   1) set CACHEFILES_DEAD bit
0144      *   2) flush requests in the xarray
0145      * Otherwise the request may be enqueued after xarray has been
0146      * flushed, leaving the orphan request never being completed.
0147      *
0148      * CPU 1            CPU 2
0149      * =====            =====
0150      * flush requests in the xarray
0151      *              test CACHEFILES_DEAD bit
0152      *              enqueue the request
0153      * set CACHEFILES_DEAD bit
0154      */
0155     smp_mb();
0156 
0157     xa_lock(xa);
0158     xa_for_each(xa, index, req) {
0159         req->error = -EIO;
0160         complete(&req->done);
0161     }
0162     xa_unlock(xa);
0163 
0164     xa_destroy(&cache->reqs);
0165     xa_destroy(&cache->ondemand_ids);
0166 }
0167 
0168 void cachefiles_put_unbind_pincount(struct cachefiles_cache *cache)
0169 {
0170     if (refcount_dec_and_test(&cache->unbind_pincount)) {
0171         cachefiles_daemon_unbind(cache);
0172         cachefiles_open = 0;
0173         kfree(cache);
0174     }
0175 }
0176 
0177 void cachefiles_get_unbind_pincount(struct cachefiles_cache *cache)
0178 {
0179     refcount_inc(&cache->unbind_pincount);
0180 }
0181 
0182 /*
0183  * Release a cache.
0184  */
0185 static int cachefiles_daemon_release(struct inode *inode, struct file *file)
0186 {
0187     struct cachefiles_cache *cache = file->private_data;
0188 
0189     _enter("");
0190 
0191     ASSERT(cache);
0192 
0193     set_bit(CACHEFILES_DEAD, &cache->flags);
0194 
0195     if (cachefiles_in_ondemand_mode(cache))
0196         cachefiles_flush_reqs(cache);
0197 
0198     /* clean up the control file interface */
0199     cache->cachefilesd = NULL;
0200     file->private_data = NULL;
0201 
0202     cachefiles_put_unbind_pincount(cache);
0203 
0204     _leave("");
0205     return 0;
0206 }
0207 
0208 static ssize_t cachefiles_do_daemon_read(struct cachefiles_cache *cache,
0209                      char __user *_buffer, size_t buflen)
0210 {
0211     unsigned long long b_released;
0212     unsigned f_released;
0213     char buffer[256];
0214     int n;
0215 
0216     /* check how much space the cache has */
0217     cachefiles_has_space(cache, 0, 0, cachefiles_has_space_check);
0218 
0219     /* summarise */
0220     f_released = atomic_xchg(&cache->f_released, 0);
0221     b_released = atomic_long_xchg(&cache->b_released, 0);
0222     clear_bit(CACHEFILES_STATE_CHANGED, &cache->flags);
0223 
0224     n = snprintf(buffer, sizeof(buffer),
0225              "cull=%c"
0226              " frun=%llx"
0227              " fcull=%llx"
0228              " fstop=%llx"
0229              " brun=%llx"
0230              " bcull=%llx"
0231              " bstop=%llx"
0232              " freleased=%x"
0233              " breleased=%llx",
0234              test_bit(CACHEFILES_CULLING, &cache->flags) ? '1' : '0',
0235              (unsigned long long) cache->frun,
0236              (unsigned long long) cache->fcull,
0237              (unsigned long long) cache->fstop,
0238              (unsigned long long) cache->brun,
0239              (unsigned long long) cache->bcull,
0240              (unsigned long long) cache->bstop,
0241              f_released,
0242              b_released);
0243 
0244     if (n > buflen)
0245         return -EMSGSIZE;
0246 
0247     if (copy_to_user(_buffer, buffer, n) != 0)
0248         return -EFAULT;
0249 
0250     return n;
0251 }
0252 
0253 /*
0254  * Read the cache state.
0255  */
0256 static ssize_t cachefiles_daemon_read(struct file *file, char __user *_buffer,
0257                       size_t buflen, loff_t *pos)
0258 {
0259     struct cachefiles_cache *cache = file->private_data;
0260 
0261     //_enter(",,%zu,", buflen);
0262 
0263     if (!test_bit(CACHEFILES_READY, &cache->flags))
0264         return 0;
0265 
0266     if (cachefiles_in_ondemand_mode(cache))
0267         return cachefiles_ondemand_daemon_read(cache, _buffer, buflen);
0268     else
0269         return cachefiles_do_daemon_read(cache, _buffer, buflen);
0270 }
0271 
0272 /*
0273  * Take a command from cachefilesd, parse it and act on it.
0274  */
0275 static ssize_t cachefiles_daemon_write(struct file *file,
0276                        const char __user *_data,
0277                        size_t datalen,
0278                        loff_t *pos)
0279 {
0280     const struct cachefiles_daemon_cmd *cmd;
0281     struct cachefiles_cache *cache = file->private_data;
0282     ssize_t ret;
0283     char *data, *args, *cp;
0284 
0285     //_enter(",,%zu,", datalen);
0286 
0287     ASSERT(cache);
0288 
0289     if (test_bit(CACHEFILES_DEAD, &cache->flags))
0290         return -EIO;
0291 
0292     if (datalen > PAGE_SIZE - 1)
0293         return -EOPNOTSUPP;
0294 
0295     /* drag the command string into the kernel so we can parse it */
0296     data = memdup_user_nul(_data, datalen);
0297     if (IS_ERR(data))
0298         return PTR_ERR(data);
0299 
0300     ret = -EINVAL;
0301     if (memchr(data, '\0', datalen))
0302         goto error;
0303 
0304     /* strip any newline */
0305     cp = memchr(data, '\n', datalen);
0306     if (cp) {
0307         if (cp == data)
0308             goto error;
0309 
0310         *cp = '\0';
0311     }
0312 
0313     /* parse the command */
0314     ret = -EOPNOTSUPP;
0315 
0316     for (args = data; *args; args++)
0317         if (isspace(*args))
0318             break;
0319     if (*args) {
0320         if (args == data)
0321             goto error;
0322         *args = '\0';
0323         args = skip_spaces(++args);
0324     }
0325 
0326     /* run the appropriate command handler */
0327     for (cmd = cachefiles_daemon_cmds; cmd->name[0]; cmd++)
0328         if (strcmp(cmd->name, data) == 0)
0329             goto found_command;
0330 
0331 error:
0332     kfree(data);
0333     //_leave(" = %zd", ret);
0334     return ret;
0335 
0336 found_command:
0337     mutex_lock(&cache->daemon_mutex);
0338 
0339     ret = -EIO;
0340     if (!test_bit(CACHEFILES_DEAD, &cache->flags))
0341         ret = cmd->handler(cache, args);
0342 
0343     mutex_unlock(&cache->daemon_mutex);
0344 
0345     if (ret == 0)
0346         ret = datalen;
0347     goto error;
0348 }
0349 
0350 /*
0351  * Poll for culling state
0352  * - use EPOLLOUT to indicate culling state
0353  */
0354 static __poll_t cachefiles_daemon_poll(struct file *file,
0355                        struct poll_table_struct *poll)
0356 {
0357     struct cachefiles_cache *cache = file->private_data;
0358     __poll_t mask;
0359 
0360     poll_wait(file, &cache->daemon_pollwq, poll);
0361     mask = 0;
0362 
0363     if (cachefiles_in_ondemand_mode(cache)) {
0364         if (!xa_empty(&cache->reqs))
0365             mask |= EPOLLIN;
0366     } else {
0367         if (test_bit(CACHEFILES_STATE_CHANGED, &cache->flags))
0368             mask |= EPOLLIN;
0369     }
0370 
0371     if (test_bit(CACHEFILES_CULLING, &cache->flags))
0372         mask |= EPOLLOUT;
0373 
0374     return mask;
0375 }
0376 
0377 /*
0378  * Give a range error for cache space constraints
0379  * - can be tail-called
0380  */
0381 static int cachefiles_daemon_range_error(struct cachefiles_cache *cache,
0382                      char *args)
0383 {
0384     pr_err("Free space limits must be in range 0%%<=stop<cull<run<100%%\n");
0385 
0386     return -EINVAL;
0387 }
0388 
0389 /*
0390  * Set the percentage of files at which to stop culling
0391  * - command: "frun <N>%"
0392  */
0393 static int cachefiles_daemon_frun(struct cachefiles_cache *cache, char *args)
0394 {
0395     unsigned long frun;
0396 
0397     _enter(",%s", args);
0398 
0399     if (!*args)
0400         return -EINVAL;
0401 
0402     frun = simple_strtoul(args, &args, 10);
0403     if (args[0] != '%' || args[1] != '\0')
0404         return -EINVAL;
0405 
0406     if (frun <= cache->fcull_percent || frun >= 100)
0407         return cachefiles_daemon_range_error(cache, args);
0408 
0409     cache->frun_percent = frun;
0410     return 0;
0411 }
0412 
0413 /*
0414  * Set the percentage of files at which to start culling
0415  * - command: "fcull <N>%"
0416  */
0417 static int cachefiles_daemon_fcull(struct cachefiles_cache *cache, char *args)
0418 {
0419     unsigned long fcull;
0420 
0421     _enter(",%s", args);
0422 
0423     if (!*args)
0424         return -EINVAL;
0425 
0426     fcull = simple_strtoul(args, &args, 10);
0427     if (args[0] != '%' || args[1] != '\0')
0428         return -EINVAL;
0429 
0430     if (fcull <= cache->fstop_percent || fcull >= cache->frun_percent)
0431         return cachefiles_daemon_range_error(cache, args);
0432 
0433     cache->fcull_percent = fcull;
0434     return 0;
0435 }
0436 
0437 /*
0438  * Set the percentage of files at which to stop allocating
0439  * - command: "fstop <N>%"
0440  */
0441 static int cachefiles_daemon_fstop(struct cachefiles_cache *cache, char *args)
0442 {
0443     unsigned long fstop;
0444 
0445     _enter(",%s", args);
0446 
0447     if (!*args)
0448         return -EINVAL;
0449 
0450     fstop = simple_strtoul(args, &args, 10);
0451     if (args[0] != '%' || args[1] != '\0')
0452         return -EINVAL;
0453 
0454     if (fstop >= cache->fcull_percent)
0455         return cachefiles_daemon_range_error(cache, args);
0456 
0457     cache->fstop_percent = fstop;
0458     return 0;
0459 }
0460 
0461 /*
0462  * Set the percentage of blocks at which to stop culling
0463  * - command: "brun <N>%"
0464  */
0465 static int cachefiles_daemon_brun(struct cachefiles_cache *cache, char *args)
0466 {
0467     unsigned long brun;
0468 
0469     _enter(",%s", args);
0470 
0471     if (!*args)
0472         return -EINVAL;
0473 
0474     brun = simple_strtoul(args, &args, 10);
0475     if (args[0] != '%' || args[1] != '\0')
0476         return -EINVAL;
0477 
0478     if (brun <= cache->bcull_percent || brun >= 100)
0479         return cachefiles_daemon_range_error(cache, args);
0480 
0481     cache->brun_percent = brun;
0482     return 0;
0483 }
0484 
0485 /*
0486  * Set the percentage of blocks at which to start culling
0487  * - command: "bcull <N>%"
0488  */
0489 static int cachefiles_daemon_bcull(struct cachefiles_cache *cache, char *args)
0490 {
0491     unsigned long bcull;
0492 
0493     _enter(",%s", args);
0494 
0495     if (!*args)
0496         return -EINVAL;
0497 
0498     bcull = simple_strtoul(args, &args, 10);
0499     if (args[0] != '%' || args[1] != '\0')
0500         return -EINVAL;
0501 
0502     if (bcull <= cache->bstop_percent || bcull >= cache->brun_percent)
0503         return cachefiles_daemon_range_error(cache, args);
0504 
0505     cache->bcull_percent = bcull;
0506     return 0;
0507 }
0508 
0509 /*
0510  * Set the percentage of blocks at which to stop allocating
0511  * - command: "bstop <N>%"
0512  */
0513 static int cachefiles_daemon_bstop(struct cachefiles_cache *cache, char *args)
0514 {
0515     unsigned long bstop;
0516 
0517     _enter(",%s", args);
0518 
0519     if (!*args)
0520         return -EINVAL;
0521 
0522     bstop = simple_strtoul(args, &args, 10);
0523     if (args[0] != '%' || args[1] != '\0')
0524         return -EINVAL;
0525 
0526     if (bstop >= cache->bcull_percent)
0527         return cachefiles_daemon_range_error(cache, args);
0528 
0529     cache->bstop_percent = bstop;
0530     return 0;
0531 }
0532 
0533 /*
0534  * Set the cache directory
0535  * - command: "dir <name>"
0536  */
0537 static int cachefiles_daemon_dir(struct cachefiles_cache *cache, char *args)
0538 {
0539     char *dir;
0540 
0541     _enter(",%s", args);
0542 
0543     if (!*args) {
0544         pr_err("Empty directory specified\n");
0545         return -EINVAL;
0546     }
0547 
0548     if (cache->rootdirname) {
0549         pr_err("Second cache directory specified\n");
0550         return -EEXIST;
0551     }
0552 
0553     dir = kstrdup(args, GFP_KERNEL);
0554     if (!dir)
0555         return -ENOMEM;
0556 
0557     cache->rootdirname = dir;
0558     return 0;
0559 }
0560 
0561 /*
0562  * Set the cache security context
0563  * - command: "secctx <ctx>"
0564  */
0565 static int cachefiles_daemon_secctx(struct cachefiles_cache *cache, char *args)
0566 {
0567     char *secctx;
0568 
0569     _enter(",%s", args);
0570 
0571     if (!*args) {
0572         pr_err("Empty security context specified\n");
0573         return -EINVAL;
0574     }
0575 
0576     if (cache->secctx) {
0577         pr_err("Second security context specified\n");
0578         return -EINVAL;
0579     }
0580 
0581     secctx = kstrdup(args, GFP_KERNEL);
0582     if (!secctx)
0583         return -ENOMEM;
0584 
0585     cache->secctx = secctx;
0586     return 0;
0587 }
0588 
0589 /*
0590  * Set the cache tag
0591  * - command: "tag <name>"
0592  */
0593 static int cachefiles_daemon_tag(struct cachefiles_cache *cache, char *args)
0594 {
0595     char *tag;
0596 
0597     _enter(",%s", args);
0598 
0599     if (!*args) {
0600         pr_err("Empty tag specified\n");
0601         return -EINVAL;
0602     }
0603 
0604     if (cache->tag)
0605         return -EEXIST;
0606 
0607     tag = kstrdup(args, GFP_KERNEL);
0608     if (!tag)
0609         return -ENOMEM;
0610 
0611     cache->tag = tag;
0612     return 0;
0613 }
0614 
0615 /*
0616  * Request a node in the cache be culled from the current working directory
0617  * - command: "cull <name>"
0618  */
0619 static int cachefiles_daemon_cull(struct cachefiles_cache *cache, char *args)
0620 {
0621     struct path path;
0622     const struct cred *saved_cred;
0623     int ret;
0624 
0625     _enter(",%s", args);
0626 
0627     if (strchr(args, '/'))
0628         goto inval;
0629 
0630     if (!test_bit(CACHEFILES_READY, &cache->flags)) {
0631         pr_err("cull applied to unready cache\n");
0632         return -EIO;
0633     }
0634 
0635     if (test_bit(CACHEFILES_DEAD, &cache->flags)) {
0636         pr_err("cull applied to dead cache\n");
0637         return -EIO;
0638     }
0639 
0640     get_fs_pwd(current->fs, &path);
0641 
0642     if (!d_can_lookup(path.dentry))
0643         goto notdir;
0644 
0645     cachefiles_begin_secure(cache, &saved_cred);
0646     ret = cachefiles_cull(cache, path.dentry, args);
0647     cachefiles_end_secure(cache, saved_cred);
0648 
0649     path_put(&path);
0650     _leave(" = %d", ret);
0651     return ret;
0652 
0653 notdir:
0654     path_put(&path);
0655     pr_err("cull command requires dirfd to be a directory\n");
0656     return -ENOTDIR;
0657 
0658 inval:
0659     pr_err("cull command requires dirfd and filename\n");
0660     return -EINVAL;
0661 }
0662 
0663 /*
0664  * Set debugging mode
0665  * - command: "debug <mask>"
0666  */
0667 static int cachefiles_daemon_debug(struct cachefiles_cache *cache, char *args)
0668 {
0669     unsigned long mask;
0670 
0671     _enter(",%s", args);
0672 
0673     mask = simple_strtoul(args, &args, 0);
0674     if (args[0] != '\0')
0675         goto inval;
0676 
0677     cachefiles_debug = mask;
0678     _leave(" = 0");
0679     return 0;
0680 
0681 inval:
0682     pr_err("debug command requires mask\n");
0683     return -EINVAL;
0684 }
0685 
0686 /*
0687  * Find out whether an object in the current working directory is in use or not
0688  * - command: "inuse <name>"
0689  */
0690 static int cachefiles_daemon_inuse(struct cachefiles_cache *cache, char *args)
0691 {
0692     struct path path;
0693     const struct cred *saved_cred;
0694     int ret;
0695 
0696     //_enter(",%s", args);
0697 
0698     if (strchr(args, '/'))
0699         goto inval;
0700 
0701     if (!test_bit(CACHEFILES_READY, &cache->flags)) {
0702         pr_err("inuse applied to unready cache\n");
0703         return -EIO;
0704     }
0705 
0706     if (test_bit(CACHEFILES_DEAD, &cache->flags)) {
0707         pr_err("inuse applied to dead cache\n");
0708         return -EIO;
0709     }
0710 
0711     get_fs_pwd(current->fs, &path);
0712 
0713     if (!d_can_lookup(path.dentry))
0714         goto notdir;
0715 
0716     cachefiles_begin_secure(cache, &saved_cred);
0717     ret = cachefiles_check_in_use(cache, path.dentry, args);
0718     cachefiles_end_secure(cache, saved_cred);
0719 
0720     path_put(&path);
0721     //_leave(" = %d", ret);
0722     return ret;
0723 
0724 notdir:
0725     path_put(&path);
0726     pr_err("inuse command requires dirfd to be a directory\n");
0727     return -ENOTDIR;
0728 
0729 inval:
0730     pr_err("inuse command requires dirfd and filename\n");
0731     return -EINVAL;
0732 }
0733 
0734 /*
0735  * Bind a directory as a cache
0736  */
0737 static int cachefiles_daemon_bind(struct cachefiles_cache *cache, char *args)
0738 {
0739     _enter("{%u,%u,%u,%u,%u,%u},%s",
0740            cache->frun_percent,
0741            cache->fcull_percent,
0742            cache->fstop_percent,
0743            cache->brun_percent,
0744            cache->bcull_percent,
0745            cache->bstop_percent,
0746            args);
0747 
0748     if (cache->fstop_percent >= cache->fcull_percent ||
0749         cache->fcull_percent >= cache->frun_percent ||
0750         cache->frun_percent  >= 100)
0751         return -ERANGE;
0752 
0753     if (cache->bstop_percent >= cache->bcull_percent ||
0754         cache->bcull_percent >= cache->brun_percent ||
0755         cache->brun_percent  >= 100)
0756         return -ERANGE;
0757 
0758     if (!cache->rootdirname) {
0759         pr_err("No cache directory specified\n");
0760         return -EINVAL;
0761     }
0762 
0763     /* Don't permit already bound caches to be re-bound */
0764     if (test_bit(CACHEFILES_READY, &cache->flags)) {
0765         pr_err("Cache already bound\n");
0766         return -EBUSY;
0767     }
0768 
0769     if (IS_ENABLED(CONFIG_CACHEFILES_ONDEMAND)) {
0770         if (!strcmp(args, "ondemand")) {
0771             set_bit(CACHEFILES_ONDEMAND_MODE, &cache->flags);
0772         } else if (*args) {
0773             pr_err("Invalid argument to the 'bind' command\n");
0774             return -EINVAL;
0775         }
0776     } else if (*args) {
0777         pr_err("'bind' command doesn't take an argument\n");
0778         return -EINVAL;
0779     }
0780 
0781     /* Make sure we have copies of the tag string */
0782     if (!cache->tag) {
0783         /*
0784          * The tag string is released by the fops->release()
0785          * function, so we don't release it on error here
0786          */
0787         cache->tag = kstrdup("CacheFiles", GFP_KERNEL);
0788         if (!cache->tag)
0789             return -ENOMEM;
0790     }
0791 
0792     return cachefiles_add_cache(cache);
0793 }
0794 
0795 /*
0796  * Unbind a cache.
0797  */
0798 static void cachefiles_daemon_unbind(struct cachefiles_cache *cache)
0799 {
0800     _enter("");
0801 
0802     if (test_bit(CACHEFILES_READY, &cache->flags))
0803         cachefiles_withdraw_cache(cache);
0804 
0805     cachefiles_put_directory(cache->graveyard);
0806     cachefiles_put_directory(cache->store);
0807     mntput(cache->mnt);
0808 
0809     kfree(cache->rootdirname);
0810     kfree(cache->secctx);
0811     kfree(cache->tag);
0812 
0813     _leave("");
0814 }
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