v4.19.13 snapshot.
diff --git a/fs/cachefiles/Kconfig b/fs/cachefiles/Kconfig
new file mode 100644
index 0000000..80e9c61
--- /dev/null
+++ b/fs/cachefiles/Kconfig
@@ -0,0 +1,39 @@
+
+config CACHEFILES
+ tristate "Filesystem caching on files"
+ depends on FSCACHE && BLOCK
+ help
+ This permits use of a mounted filesystem as a cache for other
+ filesystems - primarily networking filesystems - thus allowing fast
+ local disk to enhance the speed of slower devices.
+
+ See Documentation/filesystems/caching/cachefiles.txt for more
+ information.
+
+config CACHEFILES_DEBUG
+ bool "Debug CacheFiles"
+ depends on CACHEFILES
+ help
+ This permits debugging to be dynamically enabled in the filesystem
+ caching on files module. If this is set, the debugging output may be
+ enabled by setting bits in /sys/modules/cachefiles/parameter/debug or
+ by including a debugging specifier in /etc/cachefilesd.conf.
+
+config CACHEFILES_HISTOGRAM
+ bool "Gather latency information on CacheFiles"
+ depends on CACHEFILES && PROC_FS
+ help
+
+ This option causes latency information to be gathered on CacheFiles
+ operation and exported through file:
+
+ /proc/fs/cachefiles/histogram
+
+ The generation of this histogram adds a certain amount of overhead to
+ execution as there are a number of points at which data is gathered,
+ and on a multi-CPU system these may be on cachelines that keep
+ bouncing between CPUs. On the other hand, the histogram may be
+ useful for debugging purposes. Saying 'N' here is recommended.
+
+ See Documentation/filesystems/caching/cachefiles.txt for more
+ information.
diff --git a/fs/cachefiles/Makefile b/fs/cachefiles/Makefile
new file mode 100644
index 0000000..891dedd
--- /dev/null
+++ b/fs/cachefiles/Makefile
@@ -0,0 +1,19 @@
+# SPDX-License-Identifier: GPL-2.0
+#
+# Makefile for caching in a mounted filesystem
+#
+
+cachefiles-y := \
+ bind.o \
+ daemon.o \
+ interface.o \
+ key.o \
+ main.o \
+ namei.o \
+ rdwr.o \
+ security.o \
+ xattr.o
+
+cachefiles-$(CONFIG_CACHEFILES_HISTOGRAM) += proc.o
+
+obj-$(CONFIG_CACHEFILES) := cachefiles.o
diff --git a/fs/cachefiles/bind.c b/fs/cachefiles/bind.c
new file mode 100644
index 0000000..4a717d4
--- /dev/null
+++ b/fs/cachefiles/bind.c
@@ -0,0 +1,278 @@
+/* Bind and unbind a cache from the filesystem backing it
+ *
+ * Copyright (C) 2007 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>
+#include <linux/init.h>
+#include <linux/sched.h>
+#include <linux/completion.h>
+#include <linux/slab.h>
+#include <linux/fs.h>
+#include <linux/file.h>
+#include <linux/namei.h>
+#include <linux/mount.h>
+#include <linux/statfs.h>
+#include <linux/ctype.h>
+#include <linux/xattr.h>
+#include "internal.h"
+
+static int cachefiles_daemon_add_cache(struct cachefiles_cache *caches);
+
+/*
+ * bind a directory as a cache
+ */
+int cachefiles_daemon_bind(struct cachefiles_cache *cache, char *args)
+{
+ _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);
+
+ /* start by checking things over */
+ ASSERT(cache->fstop_percent >= 0 &&
+ cache->fstop_percent < cache->fcull_percent &&
+ cache->fcull_percent < cache->frun_percent &&
+ cache->frun_percent < 100);
+
+ ASSERT(cache->bstop_percent >= 0 &&
+ cache->bstop_percent < cache->bcull_percent &&
+ cache->bcull_percent < cache->brun_percent &&
+ cache->brun_percent < 100);
+
+ if (*args) {
+ pr_err("'bind' command doesn't take an argument\n");
+ return -EINVAL;
+ }
+
+ 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;
+ }
+
+ /* make sure we have copies of the tag and dirname strings */
+ 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;
+ }
+
+ /* add the cache */
+ return cachefiles_daemon_add_cache(cache);
+}
+
+/*
+ * add a cache
+ */
+static int cachefiles_daemon_add_cache(struct cachefiles_cache *cache)
+{
+ struct cachefiles_object *fsdef;
+ struct path path;
+ struct kstatfs stats;
+ struct dentry *graveyard, *cachedir, *root;
+ const struct cred *saved_cred;
+ int ret;
+
+ _enter("");
+
+ /* we want to work under the module's security ID */
+ ret = cachefiles_get_security_ID(cache);
+ if (ret < 0)
+ return ret;
+
+ cachefiles_begin_secure(cache, &saved_cred);
+
+ /* allocate the root index object */
+ ret = -ENOMEM;
+
+ fsdef = kmem_cache_alloc(cachefiles_object_jar, GFP_KERNEL);
+ if (!fsdef)
+ goto error_root_object;
+
+ ASSERTCMP(fsdef->backer, ==, NULL);
+
+ atomic_set(&fsdef->usage, 1);
+ fsdef->type = FSCACHE_COOKIE_TYPE_INDEX;
+
+ _debug("- fsdef %p", fsdef);
+
+ /* 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;
+
+ /* 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)
+ 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");
+ if (IS_ERR(cachedir)) {
+ ret = PTR_ERR(cachedir);
+ goto error_unsupported;
+ }
+
+ fsdef->dentry = cachedir;
+ fsdef->fscache.cookie = NULL;
+
+ ret = cachefiles_check_object_type(fsdef);
+ if (ret < 0)
+ goto error_unsupported;
+
+ /* get the graveyard directory */
+ graveyard = cachefiles_get_directory(cache, root, "graveyard");
+ if (IS_ERR(graveyard)) {
+ ret = PTR_ERR(graveyard);
+ goto error_unsupported;
+ }
+
+ cache->graveyard = graveyard;
+
+ /* publish the cache */
+ fscache_init_cache(&cache->cache,
+ &cachefiles_cache_ops,
+ "%s",
+ fsdef->dentry->d_sb->s_id);
+
+ fscache_object_init(&fsdef->fscache, &fscache_fsdef_index,
+ &cache->cache);
+
+ ret = fscache_add_cache(&cache->cache, &fsdef->fscache, cache->tag);
+ 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->cache.identifier);
+
+ /* check how much space the cache has */
+ cachefiles_has_space(cache, 0, 0);
+ cachefiles_end_secure(cache, saved_cred);
+ return 0;
+
+error_add_cache:
+ dput(cache->graveyard);
+ cache->graveyard = NULL;
+error_unsupported:
+ mntput(cache->mnt);
+ cache->mnt = NULL;
+ dput(fsdef->dentry);
+ fsdef->dentry = NULL;
+ dput(root);
+error_open_root:
+ kmem_cache_free(cachefiles_object_jar, fsdef);
+error_root_object:
+ cachefiles_end_secure(cache, saved_cred);
+ pr_err("Failed to register: %d\n", ret);
+ return ret;
+}
+
+/*
+ * unbind a cache on fd release
+ */
+void cachefiles_daemon_unbind(struct cachefiles_cache *cache)
+{
+ _enter("");
+
+ if (test_bit(CACHEFILES_READY, &cache->flags)) {
+ pr_info("File cache on %s unregistering\n",
+ cache->cache.identifier);
+
+ fscache_withdraw_cache(&cache->cache);
+ }
+
+ dput(cache->graveyard);
+ mntput(cache->mnt);
+
+ kfree(cache->rootdirname);
+ kfree(cache->secctx);
+ kfree(cache->tag);
+
+ _leave("");
+}
diff --git a/fs/cachefiles/daemon.c b/fs/cachefiles/daemon.c
new file mode 100644
index 0000000..3fdee21
--- /dev/null
+++ b/fs/cachefiles/daemon.c
@@ -0,0 +1,752 @@
+/* Daemon interface
+ *
+ * Copyright (C) 2007 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>
+#include <linux/init.h>
+#include <linux/sched.h>
+#include <linux/completion.h>
+#include <linux/slab.h>
+#include <linux/fs.h>
+#include <linux/file.h>
+#include <linux/namei.h>
+#include <linux/poll.h>
+#include <linux/mount.h>
+#include <linux/statfs.h>
+#include <linux/ctype.h>
+#include <linux/string.h>
+#include <linux/fs_struct.h>
+#include "internal.h"
+
+static int cachefiles_daemon_open(struct inode *, struct file *);
+static int cachefiles_daemon_release(struct inode *, struct file *);
+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 __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 *);
+static int cachefiles_daemon_fstop(struct cachefiles_cache *, char *);
+static int cachefiles_daemon_brun(struct cachefiles_cache *, char *);
+static int cachefiles_daemon_bcull(struct cachefiles_cache *, char *);
+static int cachefiles_daemon_bstop(struct cachefiles_cache *, char *);
+static int cachefiles_daemon_cull(struct cachefiles_cache *, char *);
+static int cachefiles_daemon_debug(struct cachefiles_cache *, char *);
+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 unsigned long cachefiles_open;
+
+const struct file_operations cachefiles_daemon_fops = {
+ .owner = THIS_MODULE,
+ .open = cachefiles_daemon_open,
+ .release = cachefiles_daemon_release,
+ .read = cachefiles_daemon_read,
+ .write = cachefiles_daemon_write,
+ .poll = cachefiles_daemon_poll,
+ .llseek = noop_llseek,
+};
+
+struct cachefiles_daemon_cmd {
+ char name[8];
+ int (*handler)(struct cachefiles_cache *cache, char *args);
+};
+
+static const struct cachefiles_daemon_cmd cachefiles_daemon_cmds[] = {
+ { "bind", cachefiles_daemon_bind },
+ { "brun", cachefiles_daemon_brun },
+ { "bcull", cachefiles_daemon_bcull },
+ { "bstop", cachefiles_daemon_bstop },
+ { "cull", cachefiles_daemon_cull },
+ { "debug", cachefiles_daemon_debug },
+ { "dir", cachefiles_daemon_dir },
+ { "frun", cachefiles_daemon_frun },
+ { "fcull", cachefiles_daemon_fcull },
+ { "fstop", cachefiles_daemon_fstop },
+ { "inuse", cachefiles_daemon_inuse },
+ { "secctx", cachefiles_daemon_secctx },
+ { "tag", cachefiles_daemon_tag },
+ { "", NULL }
+};
+
+
+/*
+ * do various checks
+ */
+static int cachefiles_daemon_open(struct inode *inode, struct file *file)
+{
+ struct cachefiles_cache *cache;
+
+ _enter("");
+
+ /* only the superuser may do this */
+ if (!capable(CAP_SYS_ADMIN))
+ return -EPERM;
+
+ /* the cachefiles device may only be open once at a time */
+ if (xchg(&cachefiles_open, 1) == 1)
+ return -EBUSY;
+
+ /* allocate a cache record */
+ cache = kzalloc(sizeof(struct cachefiles_cache), GFP_KERNEL);
+ if (!cache) {
+ cachefiles_open = 0;
+ return -ENOMEM;
+ }
+
+ mutex_init(&cache->daemon_mutex);
+ cache->active_nodes = RB_ROOT;
+ rwlock_init(&cache->active_lock);
+ init_waitqueue_head(&cache->daemon_pollwq);
+
+ /* set default caching limits
+ * - limit at 1% free space and/or free files
+ * - cull below 5% free space and/or free files
+ * - cease culling above 7% free space and/or free files
+ */
+ cache->frun_percent = 7;
+ cache->fcull_percent = 5;
+ cache->fstop_percent = 1;
+ cache->brun_percent = 7;
+ cache->bcull_percent = 5;
+ cache->bstop_percent = 1;
+
+ file->private_data = cache;
+ cache->cachefilesd = file;
+ return 0;
+}
+
+/*
+ * release a cache
+ */
+static int cachefiles_daemon_release(struct inode *inode, struct file *file)
+{
+ struct cachefiles_cache *cache = file->private_data;
+
+ _enter("");
+
+ ASSERT(cache);
+
+ set_bit(CACHEFILES_DEAD, &cache->flags);
+
+ cachefiles_daemon_unbind(cache);
+
+ ASSERT(!cache->active_nodes.rb_node);
+
+ /* clean up the control file interface */
+ cache->cachefilesd = NULL;
+ file->private_data = NULL;
+ cachefiles_open = 0;
+
+ kfree(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)
+{
+ 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);
+
+ /* 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),
+ "cull=%c"
+ " frun=%llx"
+ " fcull=%llx"
+ " fstop=%llx"
+ " brun=%llx"
+ " bcull=%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,
+ f_released,
+ b_released);
+
+ if (n > buflen)
+ return -EMSGSIZE;
+
+ if (copy_to_user(_buffer, buffer, n) != 0)
+ return -EFAULT;
+
+ return n;
+}
+
+/*
+ * command the cache
+ */
+static ssize_t cachefiles_daemon_write(struct file *file,
+ const char __user *_data,
+ size_t datalen,
+ loff_t *pos)
+{
+ const struct cachefiles_daemon_cmd *cmd;
+ struct cachefiles_cache *cache = file->private_data;
+ ssize_t ret;
+ char *data, *args, *cp;
+
+ //_enter(",,%zu,", datalen);
+
+ ASSERT(cache);
+
+ if (test_bit(CACHEFILES_DEAD, &cache->flags))
+ return -EIO;
+
+ if (datalen < 0 || datalen > PAGE_SIZE - 1)
+ return -EOPNOTSUPP;
+
+ /* drag the command string into the kernel so we can parse it */
+ data = memdup_user_nul(_data, datalen);
+ if (IS_ERR(data))
+ return PTR_ERR(data);
+
+ ret = -EINVAL;
+ if (memchr(data, '\0', datalen))
+ goto error;
+
+ /* strip any newline */
+ cp = memchr(data, '\n', datalen);
+ if (cp) {
+ if (cp == data)
+ goto error;
+
+ *cp = '\0';
+ }
+
+ /* parse the command */
+ ret = -EOPNOTSUPP;
+
+ for (args = data; *args; args++)
+ if (isspace(*args))
+ break;
+ if (*args) {
+ if (args == data)
+ goto error;
+ *args = '\0';
+ args = skip_spaces(++args);
+ }
+
+ /* run the appropriate command handler */
+ for (cmd = cachefiles_daemon_cmds; cmd->name[0]; cmd++)
+ if (strcmp(cmd->name, data) == 0)
+ goto found_command;
+
+error:
+ kfree(data);
+ //_leave(" = %zd", ret);
+ return ret;
+
+found_command:
+ mutex_lock(&cache->daemon_mutex);
+
+ ret = -EIO;
+ if (!test_bit(CACHEFILES_DEAD, &cache->flags))
+ ret = cmd->handler(cache, args);
+
+ mutex_unlock(&cache->daemon_mutex);
+
+ if (ret == 0)
+ ret = datalen;
+ goto error;
+}
+
+/*
+ * poll for culling state
+ * - use EPOLLOUT to indicate culling state
+ */
+static __poll_t cachefiles_daemon_poll(struct file *file,
+ struct poll_table_struct *poll)
+{
+ struct cachefiles_cache *cache = file->private_data;
+ __poll_t mask;
+
+ poll_wait(file, &cache->daemon_pollwq, poll);
+ mask = 0;
+
+ if (test_bit(CACHEFILES_STATE_CHANGED, &cache->flags))
+ mask |= EPOLLIN;
+
+ if (test_bit(CACHEFILES_CULLING, &cache->flags))
+ mask |= EPOLLOUT;
+
+ return mask;
+}
+
+/*
+ * give a range error for cache space constraints
+ * - can be tail-called
+ */
+static int cachefiles_daemon_range_error(struct cachefiles_cache *cache,
+ char *args)
+{
+ 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
+ * - command: "frun <N>%"
+ */
+static int cachefiles_daemon_frun(struct cachefiles_cache *cache, char *args)
+{
+ unsigned long frun;
+
+ _enter(",%s", args);
+
+ if (!*args)
+ return -EINVAL;
+
+ frun = simple_strtoul(args, &args, 10);
+ if (args[0] != '%' || args[1] != '\0')
+ return -EINVAL;
+
+ if (frun <= cache->fcull_percent || frun >= 100)
+ return cachefiles_daemon_range_error(cache, args);
+
+ cache->frun_percent = frun;
+ return 0;
+}
+
+/*
+ * set the percentage of files at which to start culling
+ * - command: "fcull <N>%"
+ */
+static int cachefiles_daemon_fcull(struct cachefiles_cache *cache, char *args)
+{
+ unsigned long fcull;
+
+ _enter(",%s", args);
+
+ if (!*args)
+ return -EINVAL;
+
+ fcull = simple_strtoul(args, &args, 10);
+ if (args[0] != '%' || args[1] != '\0')
+ return -EINVAL;
+
+ if (fcull <= cache->fstop_percent || fcull >= cache->frun_percent)
+ return cachefiles_daemon_range_error(cache, args);
+
+ cache->fcull_percent = fcull;
+ return 0;
+}
+
+/*
+ * set the percentage of files at which to stop allocating
+ * - command: "fstop <N>%"
+ */
+static int cachefiles_daemon_fstop(struct cachefiles_cache *cache, char *args)
+{
+ unsigned long fstop;
+
+ _enter(",%s", args);
+
+ if (!*args)
+ return -EINVAL;
+
+ fstop = simple_strtoul(args, &args, 10);
+ if (args[0] != '%' || args[1] != '\0')
+ return -EINVAL;
+
+ if (fstop < 0 || fstop >= cache->fcull_percent)
+ return cachefiles_daemon_range_error(cache, args);
+
+ cache->fstop_percent = fstop;
+ return 0;
+}
+
+/*
+ * set the percentage of blocks at which to stop culling
+ * - command: "brun <N>%"
+ */
+static int cachefiles_daemon_brun(struct cachefiles_cache *cache, char *args)
+{
+ unsigned long brun;
+
+ _enter(",%s", args);
+
+ if (!*args)
+ return -EINVAL;
+
+ brun = simple_strtoul(args, &args, 10);
+ if (args[0] != '%' || args[1] != '\0')
+ return -EINVAL;
+
+ if (brun <= cache->bcull_percent || brun >= 100)
+ return cachefiles_daemon_range_error(cache, args);
+
+ cache->brun_percent = brun;
+ return 0;
+}
+
+/*
+ * set the percentage of blocks at which to start culling
+ * - command: "bcull <N>%"
+ */
+static int cachefiles_daemon_bcull(struct cachefiles_cache *cache, char *args)
+{
+ unsigned long bcull;
+
+ _enter(",%s", args);
+
+ if (!*args)
+ return -EINVAL;
+
+ bcull = simple_strtoul(args, &args, 10);
+ if (args[0] != '%' || args[1] != '\0')
+ return -EINVAL;
+
+ if (bcull <= cache->bstop_percent || bcull >= cache->brun_percent)
+ return cachefiles_daemon_range_error(cache, args);
+
+ cache->bcull_percent = bcull;
+ return 0;
+}
+
+/*
+ * set the percentage of blocks at which to stop allocating
+ * - command: "bstop <N>%"
+ */
+static int cachefiles_daemon_bstop(struct cachefiles_cache *cache, char *args)
+{
+ unsigned long bstop;
+
+ _enter(",%s", args);
+
+ if (!*args)
+ return -EINVAL;
+
+ bstop = simple_strtoul(args, &args, 10);
+ if (args[0] != '%' || args[1] != '\0')
+ return -EINVAL;
+
+ if (bstop < 0 || bstop >= cache->bcull_percent)
+ return cachefiles_daemon_range_error(cache, args);
+
+ cache->bstop_percent = bstop;
+ return 0;
+}
+
+/*
+ * set the cache directory
+ * - command: "dir <name>"
+ */
+static int cachefiles_daemon_dir(struct cachefiles_cache *cache, char *args)
+{
+ char *dir;
+
+ _enter(",%s", args);
+
+ if (!*args) {
+ pr_err("Empty directory specified\n");
+ return -EINVAL;
+ }
+
+ if (cache->rootdirname) {
+ pr_err("Second cache directory specified\n");
+ return -EEXIST;
+ }
+
+ dir = kstrdup(args, GFP_KERNEL);
+ if (!dir)
+ return -ENOMEM;
+
+ cache->rootdirname = dir;
+ return 0;
+}
+
+/*
+ * set the cache security context
+ * - command: "secctx <ctx>"
+ */
+static int cachefiles_daemon_secctx(struct cachefiles_cache *cache, char *args)
+{
+ char *secctx;
+
+ _enter(",%s", args);
+
+ if (!*args) {
+ pr_err("Empty security context specified\n");
+ return -EINVAL;
+ }
+
+ if (cache->secctx) {
+ pr_err("Second security context specified\n");
+ return -EINVAL;
+ }
+
+ secctx = kstrdup(args, GFP_KERNEL);
+ if (!secctx)
+ return -ENOMEM;
+
+ cache->secctx = secctx;
+ return 0;
+}
+
+/*
+ * set the cache tag
+ * - command: "tag <name>"
+ */
+static int cachefiles_daemon_tag(struct cachefiles_cache *cache, char *args)
+{
+ char *tag;
+
+ _enter(",%s", args);
+
+ if (!*args) {
+ pr_err("Empty tag specified\n");
+ return -EINVAL;
+ }
+
+ if (cache->tag)
+ return -EEXIST;
+
+ tag = kstrdup(args, GFP_KERNEL);
+ if (!tag)
+ return -ENOMEM;
+
+ cache->tag = tag;
+ return 0;
+}
+
+/*
+ * 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)
+{
+ struct path path;
+ const struct cred *saved_cred;
+ int ret;
+
+ _enter(",%s", args);
+
+ if (strchr(args, '/'))
+ goto inval;
+
+ if (!test_bit(CACHEFILES_READY, &cache->flags)) {
+ pr_err("cull applied to unready cache\n");
+ return -EIO;
+ }
+
+ if (test_bit(CACHEFILES_DEAD, &cache->flags)) {
+ pr_err("cull applied to dead cache\n");
+ return -EIO;
+ }
+
+ /* extract the directory dentry from the cwd */
+ get_fs_pwd(current->fs, &path);
+
+ if (!d_can_lookup(path.dentry))
+ goto notdir;
+
+ cachefiles_begin_secure(cache, &saved_cred);
+ ret = cachefiles_cull(cache, path.dentry, args);
+ cachefiles_end_secure(cache, saved_cred);
+
+ path_put(&path);
+ _leave(" = %d", ret);
+ return ret;
+
+notdir:
+ path_put(&path);
+ pr_err("cull command requires dirfd to be a directory\n");
+ return -ENOTDIR;
+
+inval:
+ pr_err("cull command requires dirfd and filename\n");
+ return -EINVAL;
+}
+
+/*
+ * set debugging mode
+ * - command: "debug <mask>"
+ */
+static int cachefiles_daemon_debug(struct cachefiles_cache *cache, char *args)
+{
+ unsigned long mask;
+
+ _enter(",%s", args);
+
+ mask = simple_strtoul(args, &args, 0);
+ if (args[0] != '\0')
+ goto inval;
+
+ cachefiles_debug = mask;
+ _leave(" = 0");
+ return 0;
+
+inval:
+ pr_err("debug command requires mask\n");
+ return -EINVAL;
+}
+
+/*
+ * 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)
+{
+ struct path path;
+ const struct cred *saved_cred;
+ int ret;
+
+ //_enter(",%s", args);
+
+ if (strchr(args, '/'))
+ goto inval;
+
+ if (!test_bit(CACHEFILES_READY, &cache->flags)) {
+ pr_err("inuse applied to unready cache\n");
+ return -EIO;
+ }
+
+ if (test_bit(CACHEFILES_DEAD, &cache->flags)) {
+ pr_err("inuse applied to dead cache\n");
+ return -EIO;
+ }
+
+ /* extract the directory dentry from the cwd */
+ get_fs_pwd(current->fs, &path);
+
+ if (!d_can_lookup(path.dentry))
+ goto notdir;
+
+ cachefiles_begin_secure(cache, &saved_cred);
+ ret = cachefiles_check_in_use(cache, path.dentry, args);
+ cachefiles_end_secure(cache, saved_cred);
+
+ path_put(&path);
+ //_leave(" = %d", ret);
+ return ret;
+
+notdir:
+ path_put(&path);
+ pr_err("inuse command requires dirfd to be a directory\n");
+ return -ENOTDIR;
+
+inval:
+ 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
+ */
+int cachefiles_has_space(struct cachefiles_cache *cache,
+ unsigned fnr, unsigned bnr)
+{
+ struct kstatfs stats;
+ struct path path = {
+ .mnt = cache->mnt,
+ .dentry = cache->mnt->mnt_root,
+ };
+ int ret;
+
+ //_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;
+ }
+
+ stats.f_bavail >>= cache->bshift;
+
+ //_debug("avail %llu,%llu",
+ // (unsigned long long) stats.f_ffree,
+ // (unsigned long long) stats.f_bavail);
+
+ /* see if there is sufficient space */
+ if (stats.f_ffree > fnr)
+ stats.f_ffree -= fnr;
+ else
+ stats.f_ffree = 0;
+
+ 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);
+ }
+
+ //_leave(" = 0");
+ return 0;
+
+begin_cull:
+ if (!test_and_set_bit(CACHEFILES_CULLING, &cache->flags)) {
+ _debug("### CULL CACHE ###");
+ cachefiles_state_changed(cache);
+ }
+
+ _leave(" = %d", ret);
+ return ret;
+}
diff --git a/fs/cachefiles/interface.c b/fs/cachefiles/interface.c
new file mode 100644
index 0000000..222bc5d
--- /dev/null
+++ b/fs/cachefiles/interface.c
@@ -0,0 +1,575 @@
+/* FS-Cache interface to CacheFiles
+ *
+ * Copyright (C) 2007 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/slab.h>
+#include <linux/mount.h>
+#include "internal.h"
+
+struct cachefiles_lookup_data {
+ struct cachefiles_xattr *auxdata; /* auxiliary data */
+ char *key; /* key path */
+};
+
+static int cachefiles_attr_changed(struct fscache_object *_object);
+
+/*
+ * allocate an object record for a cookie lookup and prepare the lookup data
+ */
+static struct fscache_object *cachefiles_alloc_object(
+ struct fscache_cache *_cache,
+ struct fscache_cookie *cookie)
+{
+ struct cachefiles_lookup_data *lookup_data;
+ struct cachefiles_object *object;
+ struct cachefiles_cache *cache;
+ struct cachefiles_xattr *auxdata;
+ unsigned keylen, auxlen;
+ void *buffer, *p;
+ char *key;
+
+ cache = container_of(_cache, struct cachefiles_cache, cache);
+
+ _enter("{%s},%p,", cache->cache.identifier, cookie);
+
+ lookup_data = kmalloc(sizeof(*lookup_data), cachefiles_gfp);
+ if (!lookup_data)
+ goto nomem_lookup_data;
+
+ /* create a new object record and a temporary leaf image */
+ object = kmem_cache_alloc(cachefiles_object_jar, cachefiles_gfp);
+ if (!object)
+ goto nomem_object;
+
+ ASSERTCMP(object->backer, ==, NULL);
+
+ BUG_ON(test_bit(CACHEFILES_OBJECT_ACTIVE, &object->flags));
+ atomic_set(&object->usage, 1);
+
+ fscache_object_init(&object->fscache, cookie, &cache->cache);
+
+ object->type = cookie->def->type;
+
+ /* get hold of the raw key
+ * - stick the length on the front and leave space on the back for the
+ * encoder
+ */
+ buffer = kmalloc((2 + 512) + 3, cachefiles_gfp);
+ if (!buffer)
+ goto nomem_buffer;
+
+ keylen = cookie->key_len;
+ if (keylen <= sizeof(cookie->inline_key))
+ p = cookie->inline_key;
+ else
+ p = cookie->key;
+ memcpy(buffer + 2, p, keylen);
+
+ *(uint16_t *)buffer = keylen;
+ ((char *)buffer)[keylen + 2] = 0;
+ ((char *)buffer)[keylen + 3] = 0;
+ ((char *)buffer)[keylen + 4] = 0;
+
+ /* turn the raw key into something that can work with as a filename */
+ key = cachefiles_cook_key(buffer, keylen + 2, object->type);
+ if (!key)
+ goto nomem_key;
+
+ /* get hold of the auxiliary data and prepend the object type */
+ auxdata = buffer;
+ auxlen = cookie->aux_len;
+ if (auxlen) {
+ if (auxlen <= sizeof(cookie->inline_aux))
+ p = cookie->inline_aux;
+ else
+ p = cookie->aux;
+ memcpy(auxdata->data, p, auxlen);
+ }
+
+ auxdata->len = auxlen + 1;
+ auxdata->type = cookie->type;
+
+ lookup_data->auxdata = auxdata;
+ lookup_data->key = key;
+ object->lookup_data = lookup_data;
+
+ _leave(" = %p [%p]", &object->fscache, lookup_data);
+ return &object->fscache;
+
+nomem_key:
+ kfree(buffer);
+nomem_buffer:
+ BUG_ON(test_bit(CACHEFILES_OBJECT_ACTIVE, &object->flags));
+ kmem_cache_free(cachefiles_object_jar, object);
+ fscache_object_destroyed(&cache->cache);
+nomem_object:
+ kfree(lookup_data);
+nomem_lookup_data:
+ _leave(" = -ENOMEM");
+ return ERR_PTR(-ENOMEM);
+}
+
+/*
+ * attempt to look up the nominated node in this cache
+ * - return -ETIMEDOUT to be scheduled again
+ */
+static int cachefiles_lookup_object(struct fscache_object *_object)
+{
+ struct cachefiles_lookup_data *lookup_data;
+ struct cachefiles_object *parent, *object;
+ struct cachefiles_cache *cache;
+ const struct cred *saved_cred;
+ int ret;
+
+ _enter("{OBJ%x}", _object->debug_id);
+
+ cache = container_of(_object->cache, struct cachefiles_cache, cache);
+ parent = container_of(_object->parent,
+ struct cachefiles_object, fscache);
+ object = container_of(_object, struct cachefiles_object, fscache);
+ lookup_data = object->lookup_data;
+
+ ASSERTCMP(lookup_data, !=, NULL);
+
+ /* look up the key, creating any missing bits */
+ cachefiles_begin_secure(cache, &saved_cred);
+ ret = cachefiles_walk_to_object(parent, object,
+ lookup_data->key,
+ lookup_data->auxdata);
+ cachefiles_end_secure(cache, saved_cred);
+
+ /* polish off by setting the attributes of non-index files */
+ if (ret == 0 &&
+ object->fscache.cookie->def->type != FSCACHE_COOKIE_TYPE_INDEX)
+ cachefiles_attr_changed(&object->fscache);
+
+ if (ret < 0 && ret != -ETIMEDOUT) {
+ if (ret != -ENOBUFS)
+ pr_warn("Lookup failed error %d\n", ret);
+ fscache_object_lookup_error(&object->fscache);
+ }
+
+ _leave(" [%d]", ret);
+ return ret;
+}
+
+/*
+ * indication of lookup completion
+ */
+static void cachefiles_lookup_complete(struct fscache_object *_object)
+{
+ struct cachefiles_object *object;
+
+ object = container_of(_object, struct cachefiles_object, fscache);
+
+ _enter("{OBJ%x,%p}", object->fscache.debug_id, object->lookup_data);
+
+ if (object->lookup_data) {
+ kfree(object->lookup_data->key);
+ kfree(object->lookup_data->auxdata);
+ kfree(object->lookup_data);
+ object->lookup_data = NULL;
+ }
+}
+
+/*
+ * increment the usage count on an inode object (may fail if unmounting)
+ */
+static
+struct fscache_object *cachefiles_grab_object(struct fscache_object *_object,
+ enum fscache_obj_ref_trace why)
+{
+ struct cachefiles_object *object =
+ container_of(_object, struct cachefiles_object, fscache);
+ int u;
+
+ _enter("{OBJ%x,%d}", _object->debug_id, atomic_read(&object->usage));
+
+#ifdef CACHEFILES_DEBUG_SLAB
+ ASSERT((atomic_read(&object->usage) & 0xffff0000) != 0x6b6b0000);
+#endif
+
+ u = atomic_inc_return(&object->usage);
+ trace_cachefiles_ref(object, _object->cookie,
+ (enum cachefiles_obj_ref_trace)why, u);
+ return &object->fscache;
+}
+
+/*
+ * update the auxiliary data for an object object on disk
+ */
+static void cachefiles_update_object(struct fscache_object *_object)
+{
+ struct cachefiles_object *object;
+ struct cachefiles_xattr *auxdata;
+ struct cachefiles_cache *cache;
+ struct fscache_cookie *cookie;
+ const struct cred *saved_cred;
+ const void *aux;
+ unsigned auxlen;
+
+ _enter("{OBJ%x}", _object->debug_id);
+
+ object = container_of(_object, struct cachefiles_object, fscache);
+ cache = container_of(object->fscache.cache, struct cachefiles_cache,
+ cache);
+
+ if (!fscache_use_cookie(_object)) {
+ _leave(" [relinq]");
+ return;
+ }
+
+ cookie = object->fscache.cookie;
+ auxlen = cookie->aux_len;
+
+ if (!auxlen) {
+ fscache_unuse_cookie(_object);
+ _leave(" [no aux]");
+ return;
+ }
+
+ auxdata = kmalloc(2 + auxlen + 3, cachefiles_gfp);
+ if (!auxdata) {
+ fscache_unuse_cookie(_object);
+ _leave(" [nomem]");
+ return;
+ }
+
+ aux = (auxlen <= sizeof(cookie->inline_aux)) ?
+ cookie->inline_aux : cookie->aux;
+
+ memcpy(auxdata->data, aux, auxlen);
+ fscache_unuse_cookie(_object);
+
+ auxdata->len = auxlen + 1;
+ auxdata->type = cookie->type;
+
+ cachefiles_begin_secure(cache, &saved_cred);
+ cachefiles_update_object_xattr(object, auxdata);
+ cachefiles_end_secure(cache, saved_cred);
+ kfree(auxdata);
+ _leave("");
+}
+
+/*
+ * discard the resources pinned by an object and effect retirement if
+ * requested
+ */
+static void cachefiles_drop_object(struct fscache_object *_object)
+{
+ struct cachefiles_object *object;
+ struct cachefiles_cache *cache;
+ const struct cred *saved_cred;
+ struct inode *inode;
+ blkcnt_t i_blocks = 0;
+
+ ASSERT(_object);
+
+ object = container_of(_object, struct cachefiles_object, fscache);
+
+ _enter("{OBJ%x,%d}",
+ object->fscache.debug_id, atomic_read(&object->usage));
+
+ cache = container_of(object->fscache.cache,
+ struct cachefiles_cache, cache);
+
+#ifdef CACHEFILES_DEBUG_SLAB
+ ASSERT((atomic_read(&object->usage) & 0xffff0000) != 0x6b6b0000);
+#endif
+
+ /* We need to tidy the object up if we did in fact manage to open it.
+ * It's possible for us to get here before the object is fully
+ * initialised if the parent goes away or the object gets retired
+ * before we set it up.
+ */
+ if (object->dentry) {
+ /* delete retired objects */
+ if (test_bit(FSCACHE_OBJECT_RETIRED, &object->fscache.flags) &&
+ _object != cache->cache.fsdef
+ ) {
+ _debug("- retire object OBJ%x", object->fscache.debug_id);
+ inode = d_backing_inode(object->dentry);
+ if (inode)
+ i_blocks = inode->i_blocks;
+
+ cachefiles_begin_secure(cache, &saved_cred);
+ cachefiles_delete_object(cache, object);
+ cachefiles_end_secure(cache, saved_cred);
+ }
+
+ /* close the filesystem stuff attached to the object */
+ if (object->backer != object->dentry)
+ dput(object->backer);
+ object->backer = NULL;
+ }
+
+ /* note that the object is now inactive */
+ if (test_bit(CACHEFILES_OBJECT_ACTIVE, &object->flags))
+ cachefiles_mark_object_inactive(cache, object, i_blocks);
+
+ dput(object->dentry);
+ object->dentry = NULL;
+
+ _leave("");
+}
+
+/*
+ * dispose of a reference to an object
+ */
+static void cachefiles_put_object(struct fscache_object *_object,
+ enum fscache_obj_ref_trace why)
+{
+ struct cachefiles_object *object;
+ struct fscache_cache *cache;
+ int u;
+
+ ASSERT(_object);
+
+ object = container_of(_object, struct cachefiles_object, fscache);
+
+ _enter("{OBJ%x,%d}",
+ object->fscache.debug_id, atomic_read(&object->usage));
+
+#ifdef CACHEFILES_DEBUG_SLAB
+ ASSERT((atomic_read(&object->usage) & 0xffff0000) != 0x6b6b0000);
+#endif
+
+ ASSERTIFCMP(object->fscache.parent,
+ object->fscache.parent->n_children, >, 0);
+
+ u = atomic_dec_return(&object->usage);
+ trace_cachefiles_ref(object, _object->cookie,
+ (enum cachefiles_obj_ref_trace)why, u);
+ ASSERTCMP(u, !=, -1);
+ if (u == 0) {
+ _debug("- kill object OBJ%x", object->fscache.debug_id);
+
+ ASSERT(!test_bit(CACHEFILES_OBJECT_ACTIVE, &object->flags));
+ ASSERTCMP(object->fscache.parent, ==, NULL);
+ ASSERTCMP(object->backer, ==, NULL);
+ ASSERTCMP(object->dentry, ==, NULL);
+ ASSERTCMP(object->fscache.n_ops, ==, 0);
+ ASSERTCMP(object->fscache.n_children, ==, 0);
+
+ if (object->lookup_data) {
+ kfree(object->lookup_data->key);
+ kfree(object->lookup_data->auxdata);
+ kfree(object->lookup_data);
+ object->lookup_data = NULL;
+ }
+
+ cache = object->fscache.cache;
+ fscache_object_destroy(&object->fscache);
+ kmem_cache_free(cachefiles_object_jar, object);
+ fscache_object_destroyed(cache);
+ }
+
+ _leave("");
+}
+
+/*
+ * sync a cache
+ */
+static void cachefiles_sync_cache(struct fscache_cache *_cache)
+{
+ struct cachefiles_cache *cache;
+ const struct cred *saved_cred;
+ int ret;
+
+ _enter("%p", _cache);
+
+ cache = container_of(_cache, struct cachefiles_cache, cache);
+
+ /* 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);
+}
+
+/*
+ * check if the backing cache is updated to FS-Cache
+ * - called by FS-Cache when evaluates if need to invalidate the cache
+ */
+static int cachefiles_check_consistency(struct fscache_operation *op)
+{
+ struct cachefiles_object *object;
+ struct cachefiles_cache *cache;
+ const struct cred *saved_cred;
+ int ret;
+
+ _enter("{OBJ%x}", op->object->debug_id);
+
+ object = container_of(op->object, struct cachefiles_object, fscache);
+ cache = container_of(object->fscache.cache,
+ struct cachefiles_cache, cache);
+
+ cachefiles_begin_secure(cache, &saved_cred);
+ ret = cachefiles_check_auxdata(object);
+ cachefiles_end_secure(cache, saved_cred);
+
+ _leave(" = %d", ret);
+ return ret;
+}
+
+/*
+ * notification the attributes on an object have changed
+ * - called with reads/writes excluded by FS-Cache
+ */
+static int cachefiles_attr_changed(struct fscache_object *_object)
+{
+ struct cachefiles_object *object;
+ struct cachefiles_cache *cache;
+ const struct cred *saved_cred;
+ struct iattr newattrs;
+ uint64_t ni_size;
+ loff_t oi_size;
+ int ret;
+
+ ni_size = _object->store_limit_l;
+
+ _enter("{OBJ%x},[%llu]",
+ _object->debug_id, (unsigned long long) ni_size);
+
+ object = container_of(_object, struct cachefiles_object, fscache);
+ cache = container_of(object->fscache.cache,
+ struct cachefiles_cache, cache);
+
+ if (ni_size == object->i_size)
+ return 0;
+
+ if (!object->backer)
+ return -ENOBUFS;
+
+ ASSERT(d_is_reg(object->backer));
+
+ fscache_set_store_limit(&object->fscache, ni_size);
+
+ oi_size = i_size_read(d_backing_inode(object->backer));
+ if (oi_size == ni_size)
+ return 0;
+
+ cachefiles_begin_secure(cache, &saved_cred);
+ inode_lock(d_inode(object->backer));
+
+ /* if there's an extension to a partial page at the end of the backing
+ * file, we need to discard the partial page so that we pick up new
+ * data after it */
+ if (oi_size & ~PAGE_MASK && ni_size > oi_size) {
+ _debug("discard tail %llx", oi_size);
+ newattrs.ia_valid = ATTR_SIZE;
+ newattrs.ia_size = oi_size & PAGE_MASK;
+ ret = notify_change(object->backer, &newattrs, NULL);
+ if (ret < 0)
+ goto truncate_failed;
+ }
+
+ newattrs.ia_valid = ATTR_SIZE;
+ newattrs.ia_size = ni_size;
+ ret = notify_change(object->backer, &newattrs, NULL);
+
+truncate_failed:
+ inode_unlock(d_inode(object->backer));
+ cachefiles_end_secure(cache, saved_cred);
+
+ if (ret == -EIO) {
+ fscache_set_store_limit(&object->fscache, 0);
+ cachefiles_io_error_obj(object, "Size set failed");
+ ret = -ENOBUFS;
+ }
+
+ _leave(" = %d", ret);
+ return ret;
+}
+
+/*
+ * Invalidate an object
+ */
+static void cachefiles_invalidate_object(struct fscache_operation *op)
+{
+ struct cachefiles_object *object;
+ struct cachefiles_cache *cache;
+ const struct cred *saved_cred;
+ struct path path;
+ uint64_t ni_size;
+ int ret;
+
+ object = container_of(op->object, struct cachefiles_object, fscache);
+ cache = container_of(object->fscache.cache,
+ struct cachefiles_cache, cache);
+
+ ni_size = op->object->store_limit_l;
+
+ _enter("{OBJ%x},[%llu]",
+ op->object->debug_id, (unsigned long long)ni_size);
+
+ if (object->backer) {
+ ASSERT(d_is_reg(object->backer));
+
+ fscache_set_store_limit(&object->fscache, ni_size);
+
+ path.dentry = object->backer;
+ path.mnt = cache->mnt;
+
+ cachefiles_begin_secure(cache, &saved_cred);
+ ret = vfs_truncate(&path, 0);
+ if (ret == 0)
+ ret = vfs_truncate(&path, ni_size);
+ cachefiles_end_secure(cache, saved_cred);
+
+ if (ret != 0) {
+ fscache_set_store_limit(&object->fscache, 0);
+ if (ret == -EIO)
+ cachefiles_io_error_obj(object,
+ "Invalidate failed");
+ }
+ }
+
+ fscache_op_complete(op, true);
+ _leave("");
+}
+
+/*
+ * dissociate a cache from all the pages it was backing
+ */
+static void cachefiles_dissociate_pages(struct fscache_cache *cache)
+{
+ _enter("");
+}
+
+const struct fscache_cache_ops cachefiles_cache_ops = {
+ .name = "cachefiles",
+ .alloc_object = cachefiles_alloc_object,
+ .lookup_object = cachefiles_lookup_object,
+ .lookup_complete = cachefiles_lookup_complete,
+ .grab_object = cachefiles_grab_object,
+ .update_object = cachefiles_update_object,
+ .invalidate_object = cachefiles_invalidate_object,
+ .drop_object = cachefiles_drop_object,
+ .put_object = cachefiles_put_object,
+ .sync_cache = cachefiles_sync_cache,
+ .attr_changed = cachefiles_attr_changed,
+ .read_or_alloc_page = cachefiles_read_or_alloc_page,
+ .read_or_alloc_pages = cachefiles_read_or_alloc_pages,
+ .allocate_page = cachefiles_allocate_page,
+ .allocate_pages = cachefiles_allocate_pages,
+ .write_page = cachefiles_write_page,
+ .uncache_page = cachefiles_uncache_page,
+ .dissociate_pages = cachefiles_dissociate_pages,
+ .check_consistency = cachefiles_check_consistency,
+};
diff --git a/fs/cachefiles/internal.h b/fs/cachefiles/internal.h
new file mode 100644
index 0000000..d2f6f99
--- /dev/null
+++ b/fs/cachefiles/internal.h
@@ -0,0 +1,370 @@
+/* General netfs cache on cache files internal defs
+ *
+ * Copyright (C) 2007 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.
+ */
+
+#ifdef pr_fmt
+#undef pr_fmt
+#endif
+
+#define pr_fmt(fmt) "CacheFiles: " fmt
+
+
+#include <linux/fscache-cache.h>
+#include <linux/timer.h>
+#include <linux/wait_bit.h>
+#include <linux/cred.h>
+#include <linux/workqueue.h>
+#include <linux/security.h>
+
+struct cachefiles_cache;
+struct cachefiles_object;
+
+extern unsigned cachefiles_debug;
+#define CACHEFILES_DEBUG_KENTER 1
+#define CACHEFILES_DEBUG_KLEAVE 2
+#define CACHEFILES_DEBUG_KDEBUG 4
+
+#define cachefiles_gfp (__GFP_RECLAIM | __GFP_NORETRY | __GFP_NOMEMALLOC)
+
+/*
+ * node records
+ */
+struct cachefiles_object {
+ struct fscache_object fscache; /* fscache handle */
+ struct cachefiles_lookup_data *lookup_data; /* cached lookup data */
+ struct dentry *dentry; /* the file/dir representing this object */
+ struct dentry *backer; /* backing file */
+ loff_t i_size; /* object size */
+ unsigned long flags;
+#define CACHEFILES_OBJECT_ACTIVE 0 /* T if marked active */
+ atomic_t usage; /* object usage count */
+ uint8_t type; /* object type */
+ uint8_t new; /* T if object new */
+ spinlock_t work_lock;
+ struct rb_node active_node; /* link in active tree (dentry is key) */
+};
+
+extern struct kmem_cache *cachefiles_object_jar;
+
+/*
+ * Cache files cache definition
+ */
+struct cachefiles_cache {
+ struct fscache_cache cache; /* FS-Cache record */
+ struct vfsmount *mnt; /* mountpoint holding the cache */
+ struct dentry *graveyard; /* directory into which dead objects go */
+ struct file *cachefilesd; /* manager daemon handle */
+ const struct cred *cache_cred; /* security override for accessing cache */
+ struct mutex daemon_mutex; /* command serialisation mutex */
+ wait_queue_head_t daemon_pollwq; /* poll waitqueue for daemon */
+ struct rb_root active_nodes; /* active nodes (can't be culled) */
+ rwlock_t active_lock; /* lock for active_nodes */
+ atomic_t gravecounter; /* graveyard uniquifier */
+ atomic_t f_released; /* number of objects released lately */
+ atomic_long_t b_released; /* number of blocks released lately */
+ unsigned frun_percent; /* when to stop culling (% files) */
+ unsigned fcull_percent; /* when to start culling (% files) */
+ unsigned fstop_percent; /* when to stop allocating (% files) */
+ unsigned brun_percent; /* when to stop culling (% blocks) */
+ unsigned bcull_percent; /* when to start culling (% blocks) */
+ unsigned bstop_percent; /* when to stop allocating (% blocks) */
+ unsigned bsize; /* cache's block size */
+ unsigned bshift; /* min(ilog2(PAGE_SIZE / bsize), 0) */
+ uint64_t frun; /* when to stop culling */
+ uint64_t fcull; /* when to start culling */
+ uint64_t fstop; /* when to stop allocating */
+ sector_t brun; /* when to stop culling */
+ sector_t bcull; /* when to start culling */
+ sector_t bstop; /* when to stop allocating */
+ unsigned long flags;
+#define CACHEFILES_READY 0 /* T if cache prepared */
+#define CACHEFILES_DEAD 1 /* T if cache dead */
+#define CACHEFILES_CULLING 2 /* T if cull engaged */
+#define CACHEFILES_STATE_CHANGED 3 /* T if state changed (poll trigger) */
+ char *rootdirname; /* name of cache root directory */
+ char *secctx; /* LSM security context */
+ char *tag; /* cache binding tag */
+};
+
+/*
+ * backing file read tracking
+ */
+struct cachefiles_one_read {
+ wait_queue_entry_t monitor; /* link into monitored waitqueue */
+ struct page *back_page; /* backing file page we're waiting for */
+ struct page *netfs_page; /* netfs page we're going to fill */
+ struct fscache_retrieval *op; /* retrieval op covering this */
+ struct list_head op_link; /* link in op's todo list */
+};
+
+/*
+ * backing file write tracking
+ */
+struct cachefiles_one_write {
+ struct page *netfs_page; /* netfs page to copy */
+ struct cachefiles_object *object;
+ struct list_head obj_link; /* link in object's lists */
+ fscache_rw_complete_t end_io_func;
+ void *context;
+};
+
+/*
+ * auxiliary data xattr buffer
+ */
+struct cachefiles_xattr {
+ uint16_t len;
+ uint8_t type;
+ uint8_t data[];
+};
+
+#include <trace/events/cachefiles.h>
+
+/*
+ * note change of state for daemon
+ */
+static inline void cachefiles_state_changed(struct cachefiles_cache *cache)
+{
+ set_bit(CACHEFILES_STATE_CHANGED, &cache->flags);
+ wake_up_all(&cache->daemon_pollwq);
+}
+
+/*
+ * bind.c
+ */
+extern int cachefiles_daemon_bind(struct cachefiles_cache *cache, char *args);
+extern void cachefiles_daemon_unbind(struct cachefiles_cache *cache);
+
+/*
+ * daemon.c
+ */
+extern const struct file_operations cachefiles_daemon_fops;
+
+extern int cachefiles_has_space(struct cachefiles_cache *cache,
+ unsigned fnr, unsigned bnr);
+
+/*
+ * interface.c
+ */
+extern const struct fscache_cache_ops cachefiles_cache_ops;
+
+/*
+ * key.c
+ */
+extern char *cachefiles_cook_key(const u8 *raw, int keylen, uint8_t type);
+
+/*
+ * namei.c
+ */
+extern void cachefiles_mark_object_inactive(struct cachefiles_cache *cache,
+ struct cachefiles_object *object,
+ blkcnt_t i_blocks);
+extern int cachefiles_delete_object(struct cachefiles_cache *cache,
+ struct cachefiles_object *object);
+extern int cachefiles_walk_to_object(struct cachefiles_object *parent,
+ struct cachefiles_object *object,
+ const char *key,
+ struct cachefiles_xattr *auxdata);
+extern struct dentry *cachefiles_get_directory(struct cachefiles_cache *cache,
+ struct dentry *dir,
+ const char *name);
+
+extern int cachefiles_cull(struct cachefiles_cache *cache, struct dentry *dir,
+ char *filename);
+
+extern int cachefiles_check_in_use(struct cachefiles_cache *cache,
+ struct dentry *dir, char *filename);
+
+/*
+ * proc.c
+ */
+#ifdef CONFIG_CACHEFILES_HISTOGRAM
+extern atomic_t cachefiles_lookup_histogram[HZ];
+extern atomic_t cachefiles_mkdir_histogram[HZ];
+extern atomic_t cachefiles_create_histogram[HZ];
+
+extern int __init cachefiles_proc_init(void);
+extern void cachefiles_proc_cleanup(void);
+static inline
+void cachefiles_hist(atomic_t histogram[], unsigned long start_jif)
+{
+ unsigned long jif = jiffies - start_jif;
+ if (jif >= HZ)
+ jif = HZ - 1;
+ atomic_inc(&histogram[jif]);
+}
+
+#else
+#define cachefiles_proc_init() (0)
+#define cachefiles_proc_cleanup() do {} while (0)
+#define cachefiles_hist(hist, start_jif) do {} while (0)
+#endif
+
+/*
+ * rdwr.c
+ */
+extern int cachefiles_read_or_alloc_page(struct fscache_retrieval *,
+ struct page *, gfp_t);
+extern int cachefiles_read_or_alloc_pages(struct fscache_retrieval *,
+ struct list_head *, unsigned *,
+ gfp_t);
+extern int cachefiles_allocate_page(struct fscache_retrieval *, struct page *,
+ gfp_t);
+extern int cachefiles_allocate_pages(struct fscache_retrieval *,
+ struct list_head *, unsigned *, gfp_t);
+extern int cachefiles_write_page(struct fscache_storage *, struct page *);
+extern void cachefiles_uncache_page(struct fscache_object *, struct page *);
+
+/*
+ * security.c
+ */
+extern int cachefiles_get_security_ID(struct cachefiles_cache *cache);
+extern int cachefiles_determine_cache_security(struct cachefiles_cache *cache,
+ struct dentry *root,
+ const struct cred **_saved_cred);
+
+static inline void cachefiles_begin_secure(struct cachefiles_cache *cache,
+ const struct cred **_saved_cred)
+{
+ *_saved_cred = override_creds(cache->cache_cred);
+}
+
+static inline void cachefiles_end_secure(struct cachefiles_cache *cache,
+ const struct cred *saved_cred)
+{
+ revert_creds(saved_cred);
+}
+
+/*
+ * xattr.c
+ */
+extern int cachefiles_check_object_type(struct cachefiles_object *object);
+extern int cachefiles_set_object_xattr(struct cachefiles_object *object,
+ struct cachefiles_xattr *auxdata);
+extern int cachefiles_update_object_xattr(struct cachefiles_object *object,
+ struct cachefiles_xattr *auxdata);
+extern int cachefiles_check_auxdata(struct cachefiles_object *object);
+extern int cachefiles_check_object_xattr(struct cachefiles_object *object,
+ struct cachefiles_xattr *auxdata);
+extern int cachefiles_remove_object_xattr(struct cachefiles_cache *cache,
+ struct dentry *dentry);
+
+
+/*
+ * error handling
+ */
+
+#define cachefiles_io_error(___cache, FMT, ...) \
+do { \
+ pr_err("I/O Error: " FMT"\n", ##__VA_ARGS__); \
+ fscache_io_error(&(___cache)->cache); \
+ set_bit(CACHEFILES_DEAD, &(___cache)->flags); \
+} while (0)
+
+#define cachefiles_io_error_obj(object, FMT, ...) \
+do { \
+ struct cachefiles_cache *___cache; \
+ \
+ ___cache = container_of((object)->fscache.cache, \
+ struct cachefiles_cache, cache); \
+ cachefiles_io_error(___cache, FMT, ##__VA_ARGS__); \
+} while (0)
+
+
+/*
+ * debug tracing
+ */
+#define dbgprintk(FMT, ...) \
+ printk(KERN_DEBUG "[%-6.6s] "FMT"\n", current->comm, ##__VA_ARGS__)
+
+#define kenter(FMT, ...) dbgprintk("==> %s("FMT")", __func__, ##__VA_ARGS__)
+#define kleave(FMT, ...) dbgprintk("<== %s()"FMT"", __func__, ##__VA_ARGS__)
+#define kdebug(FMT, ...) dbgprintk(FMT, ##__VA_ARGS__)
+
+
+#if defined(__KDEBUG)
+#define _enter(FMT, ...) kenter(FMT, ##__VA_ARGS__)
+#define _leave(FMT, ...) kleave(FMT, ##__VA_ARGS__)
+#define _debug(FMT, ...) kdebug(FMT, ##__VA_ARGS__)
+
+#elif defined(CONFIG_CACHEFILES_DEBUG)
+#define _enter(FMT, ...) \
+do { \
+ if (cachefiles_debug & CACHEFILES_DEBUG_KENTER) \
+ kenter(FMT, ##__VA_ARGS__); \
+} while (0)
+
+#define _leave(FMT, ...) \
+do { \
+ if (cachefiles_debug & CACHEFILES_DEBUG_KLEAVE) \
+ kleave(FMT, ##__VA_ARGS__); \
+} while (0)
+
+#define _debug(FMT, ...) \
+do { \
+ if (cachefiles_debug & CACHEFILES_DEBUG_KDEBUG) \
+ kdebug(FMT, ##__VA_ARGS__); \
+} while (0)
+
+#else
+#define _enter(FMT, ...) no_printk("==> %s("FMT")", __func__, ##__VA_ARGS__)
+#define _leave(FMT, ...) no_printk("<== %s()"FMT"", __func__, ##__VA_ARGS__)
+#define _debug(FMT, ...) no_printk(FMT, ##__VA_ARGS__)
+#endif
+
+#if 1 /* defined(__KDEBUGALL) */
+
+#define ASSERT(X) \
+do { \
+ if (unlikely(!(X))) { \
+ pr_err("\n"); \
+ pr_err("Assertion failed\n"); \
+ BUG(); \
+ } \
+} while (0)
+
+#define ASSERTCMP(X, OP, Y) \
+do { \
+ if (unlikely(!((X) OP (Y)))) { \
+ pr_err("\n"); \
+ pr_err("Assertion failed\n"); \
+ pr_err("%lx " #OP " %lx is false\n", \
+ (unsigned long)(X), (unsigned long)(Y)); \
+ BUG(); \
+ } \
+} while (0)
+
+#define ASSERTIF(C, X) \
+do { \
+ if (unlikely((C) && !(X))) { \
+ pr_err("\n"); \
+ pr_err("Assertion failed\n"); \
+ BUG(); \
+ } \
+} while (0)
+
+#define ASSERTIFCMP(C, X, OP, Y) \
+do { \
+ if (unlikely((C) && !((X) OP (Y)))) { \
+ pr_err("\n"); \
+ pr_err("Assertion failed\n"); \
+ pr_err("%lx " #OP " %lx is false\n", \
+ (unsigned long)(X), (unsigned long)(Y)); \
+ BUG(); \
+ } \
+} while (0)
+
+#else
+
+#define ASSERT(X) do {} while (0)
+#define ASSERTCMP(X, OP, Y) do {} while (0)
+#define ASSERTIF(C, X) do {} while (0)
+#define ASSERTIFCMP(C, X, OP, Y) do {} while (0)
+
+#endif
diff --git a/fs/cachefiles/key.c b/fs/cachefiles/key.c
new file mode 100644
index 0000000..33b58c6
--- /dev/null
+++ b/fs/cachefiles/key.c
@@ -0,0 +1,159 @@
+/* Key to pathname encoder
+ *
+ * Copyright (C) 2007 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/slab.h>
+#include "internal.h"
+
+static const char cachefiles_charmap[64] =
+ "0123456789" /* 0 - 9 */
+ "abcdefghijklmnopqrstuvwxyz" /* 10 - 35 */
+ "ABCDEFGHIJKLMNOPQRSTUVWXYZ" /* 36 - 61 */
+ "_-" /* 62 - 63 */
+ ;
+
+static const char cachefiles_filecharmap[256] = {
+ /* we skip space and tab and control chars */
+ [33 ... 46] = 1, /* '!' -> '.' */
+ /* we skip '/' as it's significant to pathwalk */
+ [48 ... 127] = 1, /* '0' -> '~' */
+};
+
+/*
+ * turn the raw key into something cooked
+ * - the raw key should include the length in the two bytes at the front
+ * - the key may be up to 514 bytes in length (including the length word)
+ * - "base64" encode the strange keys, mapping 3 bytes of raw to four of
+ * cooked
+ * - need to cut the cooked key into 252 char lengths (189 raw bytes)
+ */
+char *cachefiles_cook_key(const u8 *raw, int keylen, uint8_t type)
+{
+ unsigned char csum, ch;
+ unsigned int acc;
+ char *key;
+ int loop, len, max, seg, mark, print;
+
+ _enter(",%d", keylen);
+
+ BUG_ON(keylen < 2 || keylen > 514);
+
+ csum = raw[0] + raw[1];
+ print = 1;
+ for (loop = 2; loop < keylen; loop++) {
+ ch = raw[loop];
+ csum += ch;
+ print &= cachefiles_filecharmap[ch];
+ }
+
+ if (print) {
+ /* if the path is usable ASCII, then we render it directly */
+ max = keylen - 2;
+ max += 2; /* two base64'd length chars on the front */
+ max += 5; /* @checksum/M */
+ max += 3 * 2; /* maximum number of segment dividers (".../M")
+ * is ((514 + 251) / 252) = 3
+ */
+ max += 1; /* NUL on end */
+ } else {
+ /* calculate the maximum length of the cooked key */
+ keylen = (keylen + 2) / 3;
+
+ max = keylen * 4;
+ max += 5; /* @checksum/M */
+ max += 3 * 2; /* maximum number of segment dividers (".../M")
+ * is ((514 + 188) / 189) = 3
+ */
+ max += 1; /* NUL on end */
+ }
+
+ max += 1; /* 2nd NUL on end */
+
+ _debug("max: %d", max);
+
+ key = kmalloc(max, cachefiles_gfp);
+ if (!key)
+ return NULL;
+
+ len = 0;
+
+ /* build the cooked key */
+ sprintf(key, "@%02x%c+", (unsigned) csum, 0);
+ len = 5;
+ mark = len - 1;
+
+ if (print) {
+ acc = *(uint16_t *) raw;
+ raw += 2;
+
+ key[len + 1] = cachefiles_charmap[acc & 63];
+ acc >>= 6;
+ key[len] = cachefiles_charmap[acc & 63];
+ len += 2;
+
+ seg = 250;
+ for (loop = keylen; loop > 0; loop--) {
+ if (seg <= 0) {
+ key[len++] = '\0';
+ mark = len;
+ key[len++] = '+';
+ seg = 252;
+ }
+
+ key[len++] = *raw++;
+ ASSERT(len < max);
+ }
+
+ switch (type) {
+ case FSCACHE_COOKIE_TYPE_INDEX: type = 'I'; break;
+ case FSCACHE_COOKIE_TYPE_DATAFILE: type = 'D'; break;
+ default: type = 'S'; break;
+ }
+ } else {
+ seg = 252;
+ for (loop = keylen; loop > 0; loop--) {
+ if (seg <= 0) {
+ key[len++] = '\0';
+ mark = len;
+ key[len++] = '+';
+ seg = 252;
+ }
+
+ acc = *raw++;
+ acc |= *raw++ << 8;
+ acc |= *raw++ << 16;
+
+ _debug("acc: %06x", acc);
+
+ key[len++] = cachefiles_charmap[acc & 63];
+ acc >>= 6;
+ key[len++] = cachefiles_charmap[acc & 63];
+ acc >>= 6;
+ key[len++] = cachefiles_charmap[acc & 63];
+ acc >>= 6;
+ key[len++] = cachefiles_charmap[acc & 63];
+
+ ASSERT(len < max);
+ }
+
+ switch (type) {
+ case FSCACHE_COOKIE_TYPE_INDEX: type = 'J'; break;
+ case FSCACHE_COOKIE_TYPE_DATAFILE: type = 'E'; break;
+ default: type = 'T'; break;
+ }
+ }
+
+ key[mark] = type;
+ key[len++] = 0;
+ key[len] = 0;
+
+ _leave(" = %p %d", key, len);
+ return key;
+}
diff --git a/fs/cachefiles/main.c b/fs/cachefiles/main.c
new file mode 100644
index 0000000..f54d3f5
--- /dev/null
+++ b/fs/cachefiles/main.c
@@ -0,0 +1,106 @@
+/* Network filesystem caching backend to use cache files on a premounted
+ * filesystem
+ *
+ * Copyright (C) 2007 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>
+#include <linux/init.h>
+#include <linux/sched.h>
+#include <linux/completion.h>
+#include <linux/slab.h>
+#include <linux/fs.h>
+#include <linux/file.h>
+#include <linux/namei.h>
+#include <linux/mount.h>
+#include <linux/statfs.h>
+#include <linux/sysctl.h>
+#include <linux/miscdevice.h>
+#define CREATE_TRACE_POINTS
+#include "internal.h"
+
+unsigned cachefiles_debug;
+module_param_named(debug, cachefiles_debug, uint, S_IWUSR | S_IRUGO);
+MODULE_PARM_DESC(cachefiles_debug, "CacheFiles debugging mask");
+
+MODULE_DESCRIPTION("Mounted-filesystem based cache");
+MODULE_AUTHOR("Red Hat, Inc.");
+MODULE_LICENSE("GPL");
+
+struct kmem_cache *cachefiles_object_jar;
+
+static struct miscdevice cachefiles_dev = {
+ .minor = MISC_DYNAMIC_MINOR,
+ .name = "cachefiles",
+ .fops = &cachefiles_daemon_fops,
+};
+
+static void cachefiles_object_init_once(void *_object)
+{
+ struct cachefiles_object *object = _object;
+
+ memset(object, 0, sizeof(*object));
+ spin_lock_init(&object->work_lock);
+}
+
+/*
+ * initialise the fs caching module
+ */
+static int __init cachefiles_init(void)
+{
+ int ret;
+
+ ret = misc_register(&cachefiles_dev);
+ if (ret < 0)
+ goto error_dev;
+
+ /* create an object jar */
+ ret = -ENOMEM;
+ cachefiles_object_jar =
+ kmem_cache_create("cachefiles_object_jar",
+ sizeof(struct cachefiles_object),
+ 0,
+ SLAB_HWCACHE_ALIGN,
+ cachefiles_object_init_once);
+ if (!cachefiles_object_jar) {
+ pr_notice("Failed to allocate an object jar\n");
+ goto error_object_jar;
+ }
+
+ ret = cachefiles_proc_init();
+ if (ret < 0)
+ goto error_proc;
+
+ pr_info("Loaded\n");
+ return 0;
+
+error_proc:
+ kmem_cache_destroy(cachefiles_object_jar);
+error_object_jar:
+ misc_deregister(&cachefiles_dev);
+error_dev:
+ pr_err("failed to register: %d\n", ret);
+ return ret;
+}
+
+fs_initcall(cachefiles_init);
+
+/*
+ * clean up on module removal
+ */
+static void __exit cachefiles_exit(void)
+{
+ pr_info("Unloading\n");
+
+ cachefiles_proc_cleanup();
+ kmem_cache_destroy(cachefiles_object_jar);
+ misc_deregister(&cachefiles_dev);
+}
+
+module_exit(cachefiles_exit);
diff --git a/fs/cachefiles/namei.c b/fs/cachefiles/namei.c
new file mode 100644
index 0000000..5ab411d
--- /dev/null
+++ b/fs/cachefiles/namei.c
@@ -0,0 +1,1031 @@
+/* CacheFiles path walking and related routines
+ *
+ * Copyright (C) 2007 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>
+#include <linux/sched.h>
+#include <linux/file.h>
+#include <linux/fs.h>
+#include <linux/fsnotify.h>
+#include <linux/quotaops.h>
+#include <linux/xattr.h>
+#include <linux/mount.h>
+#include <linux/namei.h>
+#include <linux/security.h>
+#include <linux/slab.h>
+#include <linux/xattr.h>
+#include "internal.h"
+
+#define CACHEFILES_KEYBUF_SIZE 512
+
+/*
+ * dump debugging info about an object
+ */
+static noinline
+void __cachefiles_printk_object(struct cachefiles_object *object,
+ const char *prefix)
+{
+ struct fscache_cookie *cookie;
+ const u8 *k;
+ unsigned loop;
+
+ pr_err("%sobject: OBJ%x\n", prefix, object->fscache.debug_id);
+ pr_err("%sobjstate=%s fl=%lx wbusy=%x ev=%lx[%lx]\n",
+ prefix, object->fscache.state->name,
+ object->fscache.flags, work_busy(&object->fscache.work),
+ object->fscache.events, object->fscache.event_mask);
+ pr_err("%sops=%u inp=%u exc=%u\n",
+ prefix, object->fscache.n_ops, object->fscache.n_in_progress,
+ object->fscache.n_exclusive);
+ pr_err("%sparent=%p\n",
+ prefix, object->fscache.parent);
+
+ spin_lock(&object->fscache.lock);
+ cookie = object->fscache.cookie;
+ if (cookie) {
+ pr_err("%scookie=%p [pr=%p nd=%p fl=%lx]\n",
+ prefix,
+ object->fscache.cookie,
+ object->fscache.cookie->parent,
+ object->fscache.cookie->netfs_data,
+ object->fscache.cookie->flags);
+ pr_err("%skey=[%u] '", prefix, cookie->key_len);
+ k = (cookie->key_len <= sizeof(cookie->inline_key)) ?
+ cookie->inline_key : cookie->key;
+ for (loop = 0; loop < cookie->key_len; loop++)
+ pr_cont("%02x", k[loop]);
+ pr_cont("'\n");
+ } else {
+ pr_err("%scookie=NULL\n", prefix);
+ }
+ spin_unlock(&object->fscache.lock);
+}
+
+/*
+ * dump debugging info about a pair of objects
+ */
+static noinline void cachefiles_printk_object(struct cachefiles_object *object,
+ struct cachefiles_object *xobject)
+{
+ if (object)
+ __cachefiles_printk_object(object, "");
+ if (xobject)
+ __cachefiles_printk_object(xobject, "x");
+}
+
+/*
+ * mark the owner of a dentry, if there is one, to indicate that that dentry
+ * has been preemptively deleted
+ * - the caller must hold the i_mutex on the dentry's parent as required to
+ * call vfs_unlink(), vfs_rmdir() or vfs_rename()
+ */
+static void cachefiles_mark_object_buried(struct cachefiles_cache *cache,
+ struct dentry *dentry,
+ enum fscache_why_object_killed why)
+{
+ struct cachefiles_object *object;
+ struct rb_node *p;
+
+ _enter(",'%pd'", dentry);
+
+ write_lock(&cache->active_lock);
+
+ p = cache->active_nodes.rb_node;
+ while (p) {
+ object = rb_entry(p, struct cachefiles_object, active_node);
+ if (object->dentry > dentry)
+ p = p->rb_left;
+ else if (object->dentry < dentry)
+ p = p->rb_right;
+ else
+ goto found_dentry;
+ }
+
+ write_unlock(&cache->active_lock);
+ trace_cachefiles_mark_buried(NULL, dentry, why);
+ _leave(" [no owner]");
+ return;
+
+ /* found the dentry for */
+found_dentry:
+ kdebug("preemptive burial: OBJ%x [%s] %p",
+ object->fscache.debug_id,
+ object->fscache.state->name,
+ dentry);
+
+ trace_cachefiles_mark_buried(object, dentry, why);
+
+ if (fscache_object_is_live(&object->fscache)) {
+ pr_err("\n");
+ pr_err("Error: Can't preemptively bury live object\n");
+ cachefiles_printk_object(object, NULL);
+ } else {
+ if (why != FSCACHE_OBJECT_IS_STALE)
+ fscache_object_mark_killed(&object->fscache, why);
+ }
+
+ write_unlock(&cache->active_lock);
+ _leave(" [owner marked]");
+}
+
+/*
+ * record the fact that an object is now active
+ */
+static int cachefiles_mark_object_active(struct cachefiles_cache *cache,
+ struct cachefiles_object *object)
+{
+ struct cachefiles_object *xobject;
+ struct rb_node **_p, *_parent = NULL;
+ struct dentry *dentry;
+
+ _enter(",%p", object);
+
+try_again:
+ write_lock(&cache->active_lock);
+
+ dentry = object->dentry;
+ trace_cachefiles_mark_active(object, dentry);
+
+ if (test_and_set_bit(CACHEFILES_OBJECT_ACTIVE, &object->flags)) {
+ pr_err("Error: Object already active\n");
+ cachefiles_printk_object(object, NULL);
+ BUG();
+ }
+
+ _p = &cache->active_nodes.rb_node;
+ while (*_p) {
+ _parent = *_p;
+ xobject = rb_entry(_parent,
+ struct cachefiles_object, active_node);
+
+ ASSERT(xobject != object);
+
+ if (xobject->dentry > dentry)
+ _p = &(*_p)->rb_left;
+ else if (xobject->dentry < dentry)
+ _p = &(*_p)->rb_right;
+ else
+ goto wait_for_old_object;
+ }
+
+ rb_link_node(&object->active_node, _parent, _p);
+ rb_insert_color(&object->active_node, &cache->active_nodes);
+
+ write_unlock(&cache->active_lock);
+ _leave(" = 0");
+ return 0;
+
+ /* an old object from a previous incarnation is hogging the slot - we
+ * need to wait for it to be destroyed */
+wait_for_old_object:
+ trace_cachefiles_wait_active(object, dentry, xobject);
+ clear_bit(CACHEFILES_OBJECT_ACTIVE, &object->flags);
+
+ if (fscache_object_is_live(&xobject->fscache)) {
+ pr_err("\n");
+ pr_err("Error: Unexpected object collision\n");
+ cachefiles_printk_object(object, xobject);
+ }
+ atomic_inc(&xobject->usage);
+ write_unlock(&cache->active_lock);
+
+ if (test_bit(CACHEFILES_OBJECT_ACTIVE, &xobject->flags)) {
+ wait_queue_head_t *wq;
+
+ signed long timeout = 60 * HZ;
+ wait_queue_entry_t wait;
+ bool requeue;
+
+ /* if the object we're waiting for is queued for processing,
+ * then just put ourselves on the queue behind it */
+ if (work_pending(&xobject->fscache.work)) {
+ _debug("queue OBJ%x behind OBJ%x immediately",
+ object->fscache.debug_id,
+ xobject->fscache.debug_id);
+ goto requeue;
+ }
+
+ /* otherwise we sleep until either the object we're waiting for
+ * is done, or the fscache_object is congested */
+ wq = bit_waitqueue(&xobject->flags, CACHEFILES_OBJECT_ACTIVE);
+ init_wait(&wait);
+ requeue = false;
+ do {
+ prepare_to_wait(wq, &wait, TASK_UNINTERRUPTIBLE);
+ if (!test_bit(CACHEFILES_OBJECT_ACTIVE, &xobject->flags))
+ break;
+
+ requeue = fscache_object_sleep_till_congested(&timeout);
+ } while (timeout > 0 && !requeue);
+ finish_wait(wq, &wait);
+
+ if (requeue &&
+ test_bit(CACHEFILES_OBJECT_ACTIVE, &xobject->flags)) {
+ _debug("queue OBJ%x behind OBJ%x after wait",
+ object->fscache.debug_id,
+ xobject->fscache.debug_id);
+ goto requeue;
+ }
+
+ if (timeout <= 0) {
+ pr_err("\n");
+ pr_err("Error: Overlong wait for old active object to go away\n");
+ cachefiles_printk_object(object, xobject);
+ goto requeue;
+ }
+ }
+
+ ASSERT(!test_bit(CACHEFILES_OBJECT_ACTIVE, &xobject->flags));
+
+ cache->cache.ops->put_object(&xobject->fscache,
+ (enum fscache_obj_ref_trace)cachefiles_obj_put_wait_retry);
+ goto try_again;
+
+requeue:
+ cache->cache.ops->put_object(&xobject->fscache,
+ (enum fscache_obj_ref_trace)cachefiles_obj_put_wait_timeo);
+ _leave(" = -ETIMEDOUT");
+ return -ETIMEDOUT;
+}
+
+/*
+ * Mark an object as being inactive.
+ */
+void cachefiles_mark_object_inactive(struct cachefiles_cache *cache,
+ struct cachefiles_object *object,
+ blkcnt_t i_blocks)
+{
+ struct dentry *dentry = object->dentry;
+ struct inode *inode = d_backing_inode(dentry);
+
+ trace_cachefiles_mark_inactive(object, dentry, inode);
+
+ write_lock(&cache->active_lock);
+ rb_erase(&object->active_node, &cache->active_nodes);
+ clear_bit(CACHEFILES_OBJECT_ACTIVE, &object->flags);
+ write_unlock(&cache->active_lock);
+
+ wake_up_bit(&object->flags, CACHEFILES_OBJECT_ACTIVE);
+
+ /* This object can now be culled, so we need to let the daemon know
+ * that there is something it can remove if it needs to.
+ */
+ atomic_long_add(i_blocks, &cache->b_released);
+ if (atomic_inc_return(&cache->f_released))
+ cachefiles_state_changed(cache);
+}
+
+/*
+ * delete an object representation from the cache
+ * - file backed objects are unlinked
+ * - directory backed objects are stuffed into the graveyard for userspace to
+ * delete
+ * - unlocks the directory mutex
+ */
+static int cachefiles_bury_object(struct cachefiles_cache *cache,
+ struct cachefiles_object *object,
+ struct dentry *dir,
+ struct dentry *rep,
+ bool preemptive,
+ enum fscache_why_object_killed why)
+{
+ struct dentry *grave, *trap;
+ struct path path, path_to_graveyard;
+ char nbuffer[8 + 8 + 1];
+ int ret;
+
+ _enter(",'%pd','%pd'", dir, rep);
+
+ _debug("remove %p from %p", rep, dir);
+
+ /* non-directories can just be unlinked */
+ if (!d_is_dir(rep)) {
+ _debug("unlink stale object");
+
+ path.mnt = cache->mnt;
+ path.dentry = dir;
+ ret = security_path_unlink(&path, rep);
+ if (ret < 0) {
+ cachefiles_io_error(cache, "Unlink security error");
+ } else {
+ trace_cachefiles_unlink(object, rep, why);
+ ret = vfs_unlink(d_inode(dir), rep, NULL);
+
+ if (preemptive)
+ cachefiles_mark_object_buried(cache, rep, why);
+ }
+
+ inode_unlock(d_inode(dir));
+
+ if (ret == -EIO)
+ cachefiles_io_error(cache, "Unlink failed");
+
+ _leave(" = %d", ret);
+ return ret;
+ }
+
+ /* directories have to be moved to the graveyard */
+ _debug("move stale object to graveyard");
+ inode_unlock(d_inode(dir));
+
+try_again:
+ /* first step is to make up a grave dentry in the graveyard */
+ sprintf(nbuffer, "%08x%08x",
+ (uint32_t) get_seconds(),
+ (uint32_t) atomic_inc_return(&cache->gravecounter));
+
+ /* do the multiway lock magic */
+ trap = lock_rename(cache->graveyard, dir);
+
+ /* do some checks before getting the grave dentry */
+ if (rep->d_parent != dir || IS_DEADDIR(d_inode(rep))) {
+ /* the entry was probably culled when we dropped the parent dir
+ * lock */
+ unlock_rename(cache->graveyard, dir);
+ _leave(" = 0 [culled?]");
+ return 0;
+ }
+
+ if (!d_can_lookup(cache->graveyard)) {
+ unlock_rename(cache->graveyard, dir);
+ cachefiles_io_error(cache, "Graveyard no longer a directory");
+ return -EIO;
+ }
+
+ if (trap == rep) {
+ unlock_rename(cache->graveyard, dir);
+ cachefiles_io_error(cache, "May not make directory loop");
+ return -EIO;
+ }
+
+ if (d_mountpoint(rep)) {
+ unlock_rename(cache->graveyard, dir);
+ cachefiles_io_error(cache, "Mountpoint in cache");
+ return -EIO;
+ }
+
+ grave = lookup_one_len(nbuffer, cache->graveyard, strlen(nbuffer));
+ if (IS_ERR(grave)) {
+ unlock_rename(cache->graveyard, dir);
+
+ if (PTR_ERR(grave) == -ENOMEM) {
+ _leave(" = -ENOMEM");
+ return -ENOMEM;
+ }
+
+ cachefiles_io_error(cache, "Lookup error %ld",
+ PTR_ERR(grave));
+ return -EIO;
+ }
+
+ if (d_is_positive(grave)) {
+ unlock_rename(cache->graveyard, dir);
+ dput(grave);
+ grave = NULL;
+ cond_resched();
+ goto try_again;
+ }
+
+ if (d_mountpoint(grave)) {
+ unlock_rename(cache->graveyard, dir);
+ dput(grave);
+ cachefiles_io_error(cache, "Mountpoint in graveyard");
+ return -EIO;
+ }
+
+ /* target should not be an ancestor of source */
+ if (trap == grave) {
+ unlock_rename(cache->graveyard, dir);
+ dput(grave);
+ cachefiles_io_error(cache, "May not make directory loop");
+ return -EIO;
+ }
+
+ /* attempt the rename */
+ path.mnt = cache->mnt;
+ path.dentry = dir;
+ path_to_graveyard.mnt = cache->mnt;
+ path_to_graveyard.dentry = cache->graveyard;
+ ret = security_path_rename(&path, rep, &path_to_graveyard, grave, 0);
+ if (ret < 0) {
+ cachefiles_io_error(cache, "Rename security error %d", ret);
+ } else {
+ trace_cachefiles_rename(object, rep, grave, why);
+ ret = vfs_rename(d_inode(dir), rep,
+ d_inode(cache->graveyard), grave, NULL, 0);
+ if (ret != 0 && ret != -ENOMEM)
+ cachefiles_io_error(cache,
+ "Rename failed with error %d", ret);
+
+ if (preemptive)
+ cachefiles_mark_object_buried(cache, rep, why);
+ }
+
+ unlock_rename(cache->graveyard, dir);
+ dput(grave);
+ _leave(" = 0");
+ return 0;
+}
+
+/*
+ * delete an object representation from the cache
+ */
+int cachefiles_delete_object(struct cachefiles_cache *cache,
+ struct cachefiles_object *object)
+{
+ struct dentry *dir;
+ int ret;
+
+ _enter(",OBJ%x{%p}", object->fscache.debug_id, object->dentry);
+
+ ASSERT(object->dentry);
+ ASSERT(d_backing_inode(object->dentry));
+ ASSERT(object->dentry->d_parent);
+
+ dir = dget_parent(object->dentry);
+
+ inode_lock_nested(d_inode(dir), I_MUTEX_PARENT);
+
+ if (test_bit(FSCACHE_OBJECT_KILLED_BY_CACHE, &object->fscache.flags)) {
+ /* object allocation for the same key preemptively deleted this
+ * object's file so that it could create its own file */
+ _debug("object preemptively buried");
+ inode_unlock(d_inode(dir));
+ ret = 0;
+ } else {
+ /* we need to check that our parent is _still_ our parent - it
+ * may have been renamed */
+ if (dir == object->dentry->d_parent) {
+ ret = cachefiles_bury_object(cache, object, dir,
+ object->dentry, false,
+ FSCACHE_OBJECT_WAS_RETIRED);
+ } else {
+ /* it got moved, presumably by cachefilesd culling it,
+ * so it's no longer in the key path and we can ignore
+ * it */
+ inode_unlock(d_inode(dir));
+ ret = 0;
+ }
+ }
+
+ dput(dir);
+ _leave(" = %d", ret);
+ return ret;
+}
+
+/*
+ * walk from the parent object to the child object through the backing
+ * filesystem, creating directories as we go
+ */
+int cachefiles_walk_to_object(struct cachefiles_object *parent,
+ struct cachefiles_object *object,
+ const char *key,
+ struct cachefiles_xattr *auxdata)
+{
+ struct cachefiles_cache *cache;
+ struct dentry *dir, *next = NULL;
+ struct inode *inode;
+ struct path path;
+ unsigned long start;
+ const char *name;
+ int ret, nlen;
+
+ _enter("OBJ%x{%p},OBJ%x,%s,",
+ parent->fscache.debug_id, parent->dentry,
+ object->fscache.debug_id, key);
+
+ cache = container_of(parent->fscache.cache,
+ struct cachefiles_cache, cache);
+ path.mnt = cache->mnt;
+
+ ASSERT(parent->dentry);
+ ASSERT(d_backing_inode(parent->dentry));
+
+ if (!(d_is_dir(parent->dentry))) {
+ // TODO: convert file to dir
+ _leave("looking up in none directory");
+ return -ENOBUFS;
+ }
+
+ dir = dget(parent->dentry);
+
+advance:
+ /* attempt to transit the first directory component */
+ name = key;
+ nlen = strlen(key);
+
+ /* key ends in a double NUL */
+ key = key + nlen + 1;
+ if (!*key)
+ key = NULL;
+
+lookup_again:
+ /* search the current directory for the element name */
+ _debug("lookup '%s'", name);
+
+ inode_lock_nested(d_inode(dir), I_MUTEX_PARENT);
+
+ start = jiffies;
+ next = lookup_one_len(name, dir, nlen);
+ cachefiles_hist(cachefiles_lookup_histogram, start);
+ if (IS_ERR(next)) {
+ trace_cachefiles_lookup(object, next, NULL);
+ goto lookup_error;
+ }
+
+ inode = d_backing_inode(next);
+ trace_cachefiles_lookup(object, next, inode);
+ _debug("next -> %p %s", next, inode ? "positive" : "negative");
+
+ if (!key)
+ object->new = !inode;
+
+ /* if this element of the path doesn't exist, then the lookup phase
+ * failed, and we can release any readers in the certain knowledge that
+ * there's nothing for them to actually read */
+ if (d_is_negative(next))
+ fscache_object_lookup_negative(&object->fscache);
+
+ /* we need to create the object if it's negative */
+ if (key || object->type == FSCACHE_COOKIE_TYPE_INDEX) {
+ /* index objects and intervening tree levels must be subdirs */
+ if (d_is_negative(next)) {
+ ret = cachefiles_has_space(cache, 1, 0);
+ if (ret < 0)
+ goto no_space_error;
+
+ path.dentry = dir;
+ ret = security_path_mkdir(&path, next, 0);
+ if (ret < 0)
+ goto create_error;
+ start = jiffies;
+ ret = vfs_mkdir(d_inode(dir), next, 0);
+ cachefiles_hist(cachefiles_mkdir_histogram, start);
+ if (!key)
+ trace_cachefiles_mkdir(object, next, ret);
+ if (ret < 0)
+ goto create_error;
+
+ if (unlikely(d_unhashed(next))) {
+ dput(next);
+ inode_unlock(d_inode(dir));
+ goto lookup_again;
+ }
+ ASSERT(d_backing_inode(next));
+
+ _debug("mkdir -> %p{%p{ino=%lu}}",
+ next, d_backing_inode(next), d_backing_inode(next)->i_ino);
+
+ } else if (!d_can_lookup(next)) {
+ pr_err("inode %lu is not a directory\n",
+ d_backing_inode(next)->i_ino);
+ ret = -ENOBUFS;
+ goto error;
+ }
+
+ } else {
+ /* non-index objects start out life as files */
+ if (d_is_negative(next)) {
+ ret = cachefiles_has_space(cache, 1, 0);
+ if (ret < 0)
+ goto no_space_error;
+
+ path.dentry = dir;
+ ret = security_path_mknod(&path, next, S_IFREG, 0);
+ if (ret < 0)
+ goto create_error;
+ start = jiffies;
+ ret = vfs_create(d_inode(dir), next, S_IFREG, true);
+ cachefiles_hist(cachefiles_create_histogram, start);
+ trace_cachefiles_create(object, next, ret);
+ if (ret < 0)
+ goto create_error;
+
+ ASSERT(d_backing_inode(next));
+
+ _debug("create -> %p{%p{ino=%lu}}",
+ next, d_backing_inode(next), d_backing_inode(next)->i_ino);
+
+ } else if (!d_can_lookup(next) &&
+ !d_is_reg(next)
+ ) {
+ pr_err("inode %lu is not a file or directory\n",
+ d_backing_inode(next)->i_ino);
+ ret = -ENOBUFS;
+ goto error;
+ }
+ }
+
+ /* process the next component */
+ if (key) {
+ _debug("advance");
+ inode_unlock(d_inode(dir));
+ dput(dir);
+ dir = next;
+ next = NULL;
+ goto advance;
+ }
+
+ /* we've found the object we were looking for */
+ object->dentry = next;
+
+ /* if we've found that the terminal object exists, then we need to
+ * check its attributes and delete it if it's out of date */
+ if (!object->new) {
+ _debug("validate '%pd'", next);
+
+ ret = cachefiles_check_object_xattr(object, auxdata);
+ if (ret == -ESTALE) {
+ /* delete the object (the deleter drops the directory
+ * mutex) */
+ object->dentry = NULL;
+
+ ret = cachefiles_bury_object(cache, object, dir, next,
+ true,
+ FSCACHE_OBJECT_IS_STALE);
+ dput(next);
+ next = NULL;
+
+ if (ret < 0)
+ goto delete_error;
+
+ _debug("redo lookup");
+ fscache_object_retrying_stale(&object->fscache);
+ goto lookup_again;
+ }
+ }
+
+ /* note that we're now using this object */
+ ret = cachefiles_mark_object_active(cache, object);
+
+ inode_unlock(d_inode(dir));
+ dput(dir);
+ dir = NULL;
+
+ if (ret == -ETIMEDOUT)
+ goto mark_active_timed_out;
+
+ _debug("=== OBTAINED_OBJECT ===");
+
+ if (object->new) {
+ /* attach data to a newly constructed terminal object */
+ ret = cachefiles_set_object_xattr(object, auxdata);
+ if (ret < 0)
+ goto check_error;
+ } else {
+ /* always update the atime on an object we've just looked up
+ * (this is used to keep track of culling, and atimes are only
+ * updated by read, write and readdir but not lookup or
+ * open) */
+ path.dentry = next;
+ touch_atime(&path);
+ }
+
+ /* open a file interface onto a data file */
+ if (object->type != FSCACHE_COOKIE_TYPE_INDEX) {
+ if (d_is_reg(object->dentry)) {
+ const struct address_space_operations *aops;
+
+ ret = -EPERM;
+ aops = d_backing_inode(object->dentry)->i_mapping->a_ops;
+ if (!aops->bmap)
+ goto check_error;
+ if (object->dentry->d_sb->s_blocksize > PAGE_SIZE)
+ goto check_error;
+
+ object->backer = object->dentry;
+ } else {
+ BUG(); // TODO: open file in data-class subdir
+ }
+ }
+
+ object->new = 0;
+ fscache_obtained_object(&object->fscache);
+
+ _leave(" = 0 [%lu]", d_backing_inode(object->dentry)->i_ino);
+ return 0;
+
+no_space_error:
+ fscache_object_mark_killed(&object->fscache, FSCACHE_OBJECT_NO_SPACE);
+create_error:
+ _debug("create error %d", ret);
+ if (ret == -EIO)
+ cachefiles_io_error(cache, "Create/mkdir failed");
+ goto error;
+
+mark_active_timed_out:
+ _debug("mark active timed out");
+ goto release_dentry;
+
+check_error:
+ _debug("check error %d", ret);
+ cachefiles_mark_object_inactive(
+ cache, object, d_backing_inode(object->dentry)->i_blocks);
+release_dentry:
+ dput(object->dentry);
+ object->dentry = NULL;
+ goto error_out;
+
+delete_error:
+ _debug("delete error %d", ret);
+ goto error_out2;
+
+lookup_error:
+ _debug("lookup error %ld", PTR_ERR(next));
+ ret = PTR_ERR(next);
+ if (ret == -EIO)
+ cachefiles_io_error(cache, "Lookup failed");
+ next = NULL;
+error:
+ inode_unlock(d_inode(dir));
+ dput(next);
+error_out2:
+ dput(dir);
+error_out:
+ _leave(" = error %d", -ret);
+ return ret;
+}
+
+/*
+ * get a subdirectory
+ */
+struct dentry *cachefiles_get_directory(struct cachefiles_cache *cache,
+ struct dentry *dir,
+ const char *dirname)
+{
+ struct dentry *subdir;
+ unsigned long start;
+ struct path path;
+ int ret;
+
+ _enter(",,%s", dirname);
+
+ /* search the current directory for the element name */
+ inode_lock(d_inode(dir));
+
+retry:
+ start = jiffies;
+ subdir = lookup_one_len(dirname, dir, strlen(dirname));
+ cachefiles_hist(cachefiles_lookup_histogram, start);
+ if (IS_ERR(subdir)) {
+ if (PTR_ERR(subdir) == -ENOMEM)
+ goto nomem_d_alloc;
+ goto lookup_error;
+ }
+
+ _debug("subdir -> %p %s",
+ subdir, d_backing_inode(subdir) ? "positive" : "negative");
+
+ /* we need to create the subdir if it doesn't exist yet */
+ if (d_is_negative(subdir)) {
+ ret = cachefiles_has_space(cache, 1, 0);
+ if (ret < 0)
+ goto mkdir_error;
+
+ _debug("attempt mkdir");
+
+ path.mnt = cache->mnt;
+ path.dentry = dir;
+ ret = security_path_mkdir(&path, subdir, 0700);
+ if (ret < 0)
+ goto mkdir_error;
+ ret = vfs_mkdir(d_inode(dir), subdir, 0700);
+ if (ret < 0)
+ goto mkdir_error;
+
+ if (unlikely(d_unhashed(subdir))) {
+ dput(subdir);
+ goto retry;
+ }
+ ASSERT(d_backing_inode(subdir));
+
+ _debug("mkdir -> %p{%p{ino=%lu}}",
+ subdir,
+ d_backing_inode(subdir),
+ d_backing_inode(subdir)->i_ino);
+ }
+
+ inode_unlock(d_inode(dir));
+
+ /* we need to make sure the subdir is a directory */
+ ASSERT(d_backing_inode(subdir));
+
+ if (!d_can_lookup(subdir)) {
+ pr_err("%s is not a directory\n", dirname);
+ ret = -EIO;
+ goto check_error;
+ }
+
+ ret = -EPERM;
+ if (!(d_backing_inode(subdir)->i_opflags & IOP_XATTR) ||
+ !d_backing_inode(subdir)->i_op->lookup ||
+ !d_backing_inode(subdir)->i_op->mkdir ||
+ !d_backing_inode(subdir)->i_op->create ||
+ !d_backing_inode(subdir)->i_op->rename ||
+ !d_backing_inode(subdir)->i_op->rmdir ||
+ !d_backing_inode(subdir)->i_op->unlink)
+ goto check_error;
+
+ _leave(" = [%lu]", d_backing_inode(subdir)->i_ino);
+ return subdir;
+
+check_error:
+ dput(subdir);
+ _leave(" = %d [check]", ret);
+ return ERR_PTR(ret);
+
+mkdir_error:
+ inode_unlock(d_inode(dir));
+ dput(subdir);
+ pr_err("mkdir %s failed with error %d\n", dirname, ret);
+ return ERR_PTR(ret);
+
+lookup_error:
+ inode_unlock(d_inode(dir));
+ ret = PTR_ERR(subdir);
+ pr_err("Lookup %s failed with error %d\n", dirname, ret);
+ return ERR_PTR(ret);
+
+nomem_d_alloc:
+ inode_unlock(d_inode(dir));
+ _leave(" = -ENOMEM");
+ return ERR_PTR(-ENOMEM);
+}
+
+/*
+ * find out if an object is in use or not
+ * - if finds object and it's not in use:
+ * - returns a pointer to the object and a reference on it
+ * - returns with the directory locked
+ */
+static struct dentry *cachefiles_check_active(struct cachefiles_cache *cache,
+ struct dentry *dir,
+ char *filename)
+{
+ struct cachefiles_object *object;
+ struct rb_node *_n;
+ struct dentry *victim;
+ unsigned long start;
+ int ret;
+
+ //_enter(",%pd/,%s",
+ // dir, filename);
+
+ /* look up the victim */
+ inode_lock_nested(d_inode(dir), I_MUTEX_PARENT);
+
+ start = jiffies;
+ victim = lookup_one_len(filename, dir, strlen(filename));
+ cachefiles_hist(cachefiles_lookup_histogram, start);
+ if (IS_ERR(victim))
+ goto lookup_error;
+
+ //_debug("victim -> %p %s",
+ // victim, d_backing_inode(victim) ? "positive" : "negative");
+
+ /* if the object is no longer there then we probably retired the object
+ * at the netfs's request whilst the cull was in progress
+ */
+ if (d_is_negative(victim)) {
+ inode_unlock(d_inode(dir));
+ dput(victim);
+ _leave(" = -ENOENT [absent]");
+ return ERR_PTR(-ENOENT);
+ }
+
+ /* check to see if we're using this object */
+ read_lock(&cache->active_lock);
+
+ _n = cache->active_nodes.rb_node;
+
+ while (_n) {
+ object = rb_entry(_n, struct cachefiles_object, active_node);
+
+ if (object->dentry > victim)
+ _n = _n->rb_left;
+ else if (object->dentry < victim)
+ _n = _n->rb_right;
+ else
+ goto object_in_use;
+ }
+
+ read_unlock(&cache->active_lock);
+
+ //_leave(" = %p", victim);
+ return victim;
+
+object_in_use:
+ read_unlock(&cache->active_lock);
+ inode_unlock(d_inode(dir));
+ dput(victim);
+ //_leave(" = -EBUSY [in use]");
+ return ERR_PTR(-EBUSY);
+
+lookup_error:
+ inode_unlock(d_inode(dir));
+ ret = PTR_ERR(victim);
+ if (ret == -ENOENT) {
+ /* file or dir now absent - probably retired by netfs */
+ _leave(" = -ESTALE [absent]");
+ return ERR_PTR(-ESTALE);
+ }
+
+ if (ret == -EIO) {
+ cachefiles_io_error(cache, "Lookup failed");
+ } else if (ret != -ENOMEM) {
+ pr_err("Internal error: %d\n", ret);
+ ret = -EIO;
+ }
+
+ _leave(" = %d", ret);
+ return ERR_PTR(ret);
+}
+
+/*
+ * cull an object if it's not in use
+ * - called only by cache manager daemon
+ */
+int cachefiles_cull(struct cachefiles_cache *cache, struct dentry *dir,
+ char *filename)
+{
+ struct dentry *victim;
+ int ret;
+
+ _enter(",%pd/,%s", dir, filename);
+
+ victim = cachefiles_check_active(cache, dir, filename);
+ if (IS_ERR(victim))
+ return PTR_ERR(victim);
+
+ _debug("victim -> %p %s",
+ victim, d_backing_inode(victim) ? "positive" : "negative");
+
+ /* okay... the victim is not being used so we can cull it
+ * - start by marking it as stale
+ */
+ _debug("victim is cullable");
+
+ ret = cachefiles_remove_object_xattr(cache, victim);
+ if (ret < 0)
+ goto error_unlock;
+
+ /* actually remove the victim (drops the dir mutex) */
+ _debug("bury");
+
+ ret = cachefiles_bury_object(cache, NULL, dir, victim, false,
+ FSCACHE_OBJECT_WAS_CULLED);
+ if (ret < 0)
+ goto error;
+
+ dput(victim);
+ _leave(" = 0");
+ return 0;
+
+error_unlock:
+ inode_unlock(d_inode(dir));
+error:
+ dput(victim);
+ if (ret == -ENOENT) {
+ /* file or dir now absent - probably retired by netfs */
+ _leave(" = -ESTALE [absent]");
+ return -ESTALE;
+ }
+
+ if (ret != -ENOMEM) {
+ pr_err("Internal error: %d\n", ret);
+ ret = -EIO;
+ }
+
+ _leave(" = %d", ret);
+ return ret;
+}
+
+/*
+ * find out if an object is in use or not
+ * - called only by cache manager daemon
+ * - returns -EBUSY or 0 to indicate whether an object is in use or not
+ */
+int cachefiles_check_in_use(struct cachefiles_cache *cache, struct dentry *dir,
+ char *filename)
+{
+ struct dentry *victim;
+
+ //_enter(",%pd/,%s",
+ // dir, filename);
+
+ victim = cachefiles_check_active(cache, dir, filename);
+ if (IS_ERR(victim))
+ return PTR_ERR(victim);
+
+ inode_unlock(d_inode(dir));
+ dput(victim);
+ //_leave(" = 0");
+ return 0;
+}
diff --git a/fs/cachefiles/proc.c b/fs/cachefiles/proc.c
new file mode 100644
index 0000000..0ce1aa5
--- /dev/null
+++ b/fs/cachefiles/proc.c
@@ -0,0 +1,118 @@
+/* CacheFiles statistics
+ *
+ * Copyright (C) 2007 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>
+#include <linux/proc_fs.h>
+#include <linux/seq_file.h>
+#include "internal.h"
+
+atomic_t cachefiles_lookup_histogram[HZ];
+atomic_t cachefiles_mkdir_histogram[HZ];
+atomic_t cachefiles_create_histogram[HZ];
+
+/*
+ * display the latency histogram
+ */
+static int cachefiles_histogram_show(struct seq_file *m, void *v)
+{
+ unsigned long index;
+ unsigned x, y, z, t;
+
+ switch ((unsigned long) v) {
+ case 1:
+ seq_puts(m, "JIFS SECS LOOKUPS MKDIRS CREATES\n");
+ return 0;
+ case 2:
+ seq_puts(m, "===== ===== ========= ========= =========\n");
+ return 0;
+ default:
+ index = (unsigned long) v - 3;
+ x = atomic_read(&cachefiles_lookup_histogram[index]);
+ y = atomic_read(&cachefiles_mkdir_histogram[index]);
+ z = atomic_read(&cachefiles_create_histogram[index]);
+ if (x == 0 && y == 0 && z == 0)
+ return 0;
+
+ t = (index * 1000) / HZ;
+
+ seq_printf(m, "%4lu 0.%03u %9u %9u %9u\n", index, t, x, y, z);
+ return 0;
+ }
+}
+
+/*
+ * set up the iterator to start reading from the first line
+ */
+static void *cachefiles_histogram_start(struct seq_file *m, loff_t *_pos)
+{
+ if ((unsigned long long)*_pos >= HZ + 2)
+ return NULL;
+ if (*_pos == 0)
+ *_pos = 1;
+ return (void *)(unsigned long) *_pos;
+}
+
+/*
+ * move to the next line
+ */
+static void *cachefiles_histogram_next(struct seq_file *m, void *v, loff_t *pos)
+{
+ (*pos)++;
+ return (unsigned long long)*pos > HZ + 2 ?
+ NULL : (void *)(unsigned long) *pos;
+}
+
+/*
+ * clean up after reading
+ */
+static void cachefiles_histogram_stop(struct seq_file *m, void *v)
+{
+}
+
+static const struct seq_operations cachefiles_histogram_ops = {
+ .start = cachefiles_histogram_start,
+ .stop = cachefiles_histogram_stop,
+ .next = cachefiles_histogram_next,
+ .show = cachefiles_histogram_show,
+};
+
+/*
+ * initialise the /proc/fs/cachefiles/ directory
+ */
+int __init cachefiles_proc_init(void)
+{
+ _enter("");
+
+ if (!proc_mkdir("fs/cachefiles", NULL))
+ goto error_dir;
+
+ if (!proc_create_seq("fs/cachefiles/histogram", S_IFREG | 0444, NULL,
+ &cachefiles_histogram_ops))
+ goto error_histogram;
+
+ _leave(" = 0");
+ return 0;
+
+error_histogram:
+ remove_proc_entry("fs/cachefiles", NULL);
+error_dir:
+ _leave(" = -ENOMEM");
+ return -ENOMEM;
+}
+
+/*
+ * clean up the /proc/fs/cachefiles/ directory
+ */
+void cachefiles_proc_cleanup(void)
+{
+ remove_proc_entry("fs/cachefiles/histogram", NULL);
+ remove_proc_entry("fs/cachefiles", NULL);
+}
diff --git a/fs/cachefiles/rdwr.c b/fs/cachefiles/rdwr.c
new file mode 100644
index 0000000..8a57740
--- /dev/null
+++ b/fs/cachefiles/rdwr.c
@@ -0,0 +1,977 @@
+/* Storage object read/write
+ *
+ * Copyright (C) 2007 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/mount.h>
+#include <linux/slab.h>
+#include <linux/file.h>
+#include <linux/swap.h>
+#include "internal.h"
+
+/*
+ * detect wake up events generated by the unlocking of pages in which we're
+ * interested
+ * - we use this to detect read completion of backing pages
+ * - the caller holds the waitqueue lock
+ */
+static int cachefiles_read_waiter(wait_queue_entry_t *wait, unsigned mode,
+ int sync, void *_key)
+{
+ struct cachefiles_one_read *monitor =
+ container_of(wait, struct cachefiles_one_read, monitor);
+ struct cachefiles_object *object;
+ struct fscache_retrieval *op = monitor->op;
+ struct wait_bit_key *key = _key;
+ struct page *page = wait->private;
+
+ ASSERT(key);
+
+ _enter("{%lu},%u,%d,{%p,%u}",
+ monitor->netfs_page->index, mode, sync,
+ key->flags, key->bit_nr);
+
+ if (key->flags != &page->flags ||
+ key->bit_nr != PG_locked)
+ return 0;
+
+ _debug("--- monitor %p %lx ---", page, page->flags);
+
+ if (!PageUptodate(page) && !PageError(page)) {
+ /* unlocked, not uptodate and not erronous? */
+ _debug("page probably truncated");
+ }
+
+ /* remove from the waitqueue */
+ list_del(&wait->entry);
+
+ /* move onto the action list and queue for FS-Cache thread pool */
+ ASSERT(op);
+
+ /* We need to temporarily bump the usage count as we don't own a ref
+ * here otherwise cachefiles_read_copier() may free the op between the
+ * monitor being enqueued on the op->to_do list and the op getting
+ * enqueued on the work queue.
+ */
+ fscache_get_retrieval(op);
+
+ object = container_of(op->op.object, struct cachefiles_object, fscache);
+ spin_lock(&object->work_lock);
+ list_add_tail(&monitor->op_link, &op->to_do);
+ spin_unlock(&object->work_lock);
+
+ fscache_enqueue_retrieval(op);
+ fscache_put_retrieval(op);
+ return 0;
+}
+
+/*
+ * handle a probably truncated page
+ * - check to see if the page is still relevant and reissue the read if
+ * possible
+ * - return -EIO on error, -ENODATA if the page is gone, -EINPROGRESS if we
+ * must wait again and 0 if successful
+ */
+static int cachefiles_read_reissue(struct cachefiles_object *object,
+ struct cachefiles_one_read *monitor)
+{
+ struct address_space *bmapping = d_backing_inode(object->backer)->i_mapping;
+ struct page *backpage = monitor->back_page, *backpage2;
+ int ret;
+
+ _enter("{ino=%lx},{%lx,%lx}",
+ d_backing_inode(object->backer)->i_ino,
+ backpage->index, backpage->flags);
+
+ /* skip if the page was truncated away completely */
+ if (backpage->mapping != bmapping) {
+ _leave(" = -ENODATA [mapping]");
+ return -ENODATA;
+ }
+
+ backpage2 = find_get_page(bmapping, backpage->index);
+ if (!backpage2) {
+ _leave(" = -ENODATA [gone]");
+ return -ENODATA;
+ }
+
+ if (backpage != backpage2) {
+ put_page(backpage2);
+ _leave(" = -ENODATA [different]");
+ return -ENODATA;
+ }
+
+ /* the page is still there and we already have a ref on it, so we don't
+ * need a second */
+ put_page(backpage2);
+
+ INIT_LIST_HEAD(&monitor->op_link);
+ add_page_wait_queue(backpage, &monitor->monitor);
+
+ if (trylock_page(backpage)) {
+ ret = -EIO;
+ if (PageError(backpage))
+ goto unlock_discard;
+ ret = 0;
+ if (PageUptodate(backpage))
+ goto unlock_discard;
+
+ _debug("reissue read");
+ ret = bmapping->a_ops->readpage(NULL, backpage);
+ if (ret < 0)
+ goto unlock_discard;
+ }
+
+ /* but the page may have been read before the monitor was installed, so
+ * the monitor may miss the event - so we have to ensure that we do get
+ * one in such a case */
+ if (trylock_page(backpage)) {
+ _debug("jumpstart %p {%lx}", backpage, backpage->flags);
+ unlock_page(backpage);
+ }
+
+ /* it'll reappear on the todo list */
+ _leave(" = -EINPROGRESS");
+ return -EINPROGRESS;
+
+unlock_discard:
+ unlock_page(backpage);
+ spin_lock_irq(&object->work_lock);
+ list_del(&monitor->op_link);
+ spin_unlock_irq(&object->work_lock);
+ _leave(" = %d", ret);
+ return ret;
+}
+
+/*
+ * copy data from backing pages to netfs pages to complete a read operation
+ * - driven by FS-Cache's thread pool
+ */
+static void cachefiles_read_copier(struct fscache_operation *_op)
+{
+ struct cachefiles_one_read *monitor;
+ struct cachefiles_object *object;
+ struct fscache_retrieval *op;
+ int error, max;
+
+ op = container_of(_op, struct fscache_retrieval, op);
+ object = container_of(op->op.object,
+ struct cachefiles_object, fscache);
+
+ _enter("{ino=%lu}", d_backing_inode(object->backer)->i_ino);
+
+ max = 8;
+ spin_lock_irq(&object->work_lock);
+
+ while (!list_empty(&op->to_do)) {
+ monitor = list_entry(op->to_do.next,
+ struct cachefiles_one_read, op_link);
+ list_del(&monitor->op_link);
+
+ spin_unlock_irq(&object->work_lock);
+
+ _debug("- copy {%lu}", monitor->back_page->index);
+
+ recheck:
+ 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);
+ error = 0;
+ } else if (!PageError(monitor->back_page)) {
+ /* the page has probably been truncated */
+ error = cachefiles_read_reissue(object, monitor);
+ if (error == -EINPROGRESS)
+ goto next;
+ goto recheck;
+ } else {
+ cachefiles_io_error_obj(
+ object,
+ "Readpage failed on backing file %lx",
+ (unsigned long) monitor->back_page->flags);
+ error = -EIO;
+ }
+
+ put_page(monitor->back_page);
+
+ fscache_end_io(op, monitor->netfs_page, error);
+ put_page(monitor->netfs_page);
+ fscache_retrieval_complete(op, 1);
+ fscache_put_retrieval(op);
+ kfree(monitor);
+
+ next:
+ /* let the thread pool have some air occasionally */
+ max--;
+ if (max < 0 || need_resched()) {
+ if (!list_empty(&op->to_do))
+ fscache_enqueue_retrieval(op);
+ _leave(" [maxed out]");
+ return;
+ }
+
+ spin_lock_irq(&object->work_lock);
+ }
+
+ spin_unlock_irq(&object->work_lock);
+ _leave("");
+}
+
+/*
+ * read the corresponding page to the given set from the backing file
+ * - an uncertain page is simply discarded, to be tried again another time
+ */
+static int cachefiles_read_backing_file_one(struct cachefiles_object *object,
+ struct fscache_retrieval *op,
+ struct page *netpage)
+{
+ struct cachefiles_one_read *monitor;
+ struct address_space *bmapping;
+ struct page *newpage, *backpage;
+ int ret;
+
+ _enter("");
+
+ _debug("read back %p{%lu,%d}",
+ netpage, netpage->index, page_count(netpage));
+
+ monitor = kzalloc(sizeof(*monitor), cachefiles_gfp);
+ if (!monitor)
+ goto nomem;
+
+ monitor->netfs_page = netpage;
+ monitor->op = fscache_get_retrieval(op);
+
+ init_waitqueue_func_entry(&monitor->monitor, cachefiles_read_waiter);
+
+ /* attempt to get hold of the backing page */
+ bmapping = d_backing_inode(object->backer)->i_mapping;
+ newpage = NULL;
+
+ for (;;) {
+ backpage = find_get_page(bmapping, netpage->index);
+ if (backpage)
+ goto backing_page_already_present;
+
+ if (!newpage) {
+ newpage = __page_cache_alloc(cachefiles_gfp);
+ if (!newpage)
+ goto nomem_monitor;
+ }
+
+ ret = add_to_page_cache_lru(newpage, bmapping,
+ netpage->index, cachefiles_gfp);
+ if (ret == 0)
+ goto installed_new_backing_page;
+ if (ret != -EEXIST)
+ goto nomem_page;
+ }
+
+ /* we've installed a new backing page, so now we need to start
+ * it reading */
+installed_new_backing_page:
+ _debug("- new %p", newpage);
+
+ backpage = newpage;
+ newpage = NULL;
+
+read_backing_page:
+ ret = bmapping->a_ops->readpage(NULL, backpage);
+ if (ret < 0)
+ goto read_error;
+
+ /* set the monitor to transfer the data across */
+monitor_backing_page:
+ _debug("- monitor add");
+
+ /* install the monitor */
+ get_page(monitor->netfs_page);
+ get_page(backpage);
+ monitor->back_page = backpage;
+ monitor->monitor.private = backpage;
+ add_page_wait_queue(backpage, &monitor->monitor);
+ monitor = NULL;
+
+ /* but the page may have been read before the monitor was installed, so
+ * the monitor may miss the event - so we have to ensure that we do get
+ * one in such a case */
+ if (trylock_page(backpage)) {
+ _debug("jumpstart %p {%lx}", backpage, backpage->flags);
+ unlock_page(backpage);
+ }
+ goto success;
+
+ /* if the backing page is already present, it can be in one of
+ * three states: read in progress, read failed or read okay */
+backing_page_already_present:
+ _debug("- present");
+
+ if (newpage) {
+ put_page(newpage);
+ newpage = NULL;
+ }
+
+ if (PageError(backpage))
+ goto io_error;
+
+ if (PageUptodate(backpage))
+ goto backing_page_already_uptodate;
+
+ if (!trylock_page(backpage))
+ goto monitor_backing_page;
+ _debug("read %p {%lx}", backpage, backpage->flags);
+ goto read_backing_page;
+
+ /* the backing page is already up to date, attach the netfs
+ * page to the pagecache and LRU and copy the data across */
+backing_page_already_uptodate:
+ _debug("- uptodate");
+
+ fscache_mark_page_cached(op, netpage);
+
+ copy_highpage(netpage, backpage);
+ fscache_end_io(op, netpage, 0);
+ fscache_retrieval_complete(op, 1);
+
+success:
+ _debug("success");
+ ret = 0;
+
+out:
+ if (backpage)
+ put_page(backpage);
+ if (monitor) {
+ fscache_put_retrieval(monitor->op);
+ kfree(monitor);
+ }
+ _leave(" = %d", ret);
+ return ret;
+
+read_error:
+ _debug("read error %d", ret);
+ if (ret == -ENOMEM) {
+ fscache_retrieval_complete(op, 1);
+ goto out;
+ }
+io_error:
+ cachefiles_io_error_obj(object, "Page read error on backing file");
+ fscache_retrieval_complete(op, 1);
+ ret = -ENOBUFS;
+ goto out;
+
+nomem_page:
+ put_page(newpage);
+nomem_monitor:
+ fscache_put_retrieval(monitor->op);
+ kfree(monitor);
+nomem:
+ fscache_retrieval_complete(op, 1);
+ _leave(" = -ENOMEM");
+ return -ENOMEM;
+}
+
+/*
+ * read a page from the cache or allocate a block in which to store it
+ * - cache withdrawal is prevented by the caller
+ * - returns -EINTR if interrupted
+ * - returns -ENOMEM if ran out of memory
+ * - returns -ENOBUFS if no buffers can be made available
+ * - returns -ENOBUFS if page is beyond EOF
+ * - if the page is backed by a block in the cache:
+ * - a read will be started which will call the callback on completion
+ * - 0 will be returned
+ * - else if the page is unbacked:
+ * - the metadata will be retained
+ * - -ENODATA will be returned
+ */
+int cachefiles_read_or_alloc_page(struct fscache_retrieval *op,
+ struct page *page,
+ gfp_t gfp)
+{
+ struct cachefiles_object *object;
+ struct cachefiles_cache *cache;
+ struct inode *inode;
+ sector_t block0, block;
+ unsigned shift;
+ int ret;
+
+ object = container_of(op->op.object,
+ struct cachefiles_object, fscache);
+ cache = container_of(object->fscache.cache,
+ struct cachefiles_cache, cache);
+
+ _enter("{%p},{%lx},,,", object, page->index);
+
+ if (!object->backer)
+ goto enobufs;
+
+ inode = d_backing_inode(object->backer);
+ ASSERT(S_ISREG(inode->i_mode));
+ ASSERT(inode->i_mapping->a_ops->bmap);
+ ASSERT(inode->i_mapping->a_ops->readpages);
+
+ /* calculate the shift required to use bmap */
+ shift = PAGE_SHIFT - inode->i_sb->s_blocksize_bits;
+
+ op->op.flags &= FSCACHE_OP_KEEP_FLAGS;
+ op->op.flags |= FSCACHE_OP_ASYNC;
+ op->op.processor = cachefiles_read_copier;
+
+ /* we assume the absence or presence of the first block is a good
+ * enough indication for the page as a whole
+ * - TODO: don't use bmap() for this as it is _not_ actually good
+ * enough for this as it doesn't indicate errors, but it's all we've
+ * got for the moment
+ */
+ block0 = page->index;
+ block0 <<= shift;
+
+ block = inode->i_mapping->a_ops->bmap(inode->i_mapping, block0);
+ _debug("%llx -> %llx",
+ (unsigned long long) block0,
+ (unsigned long long) block);
+
+ if (block) {
+ /* submit the apparently valid page to the backing fs to be
+ * read from disk */
+ ret = cachefiles_read_backing_file_one(object, op, page);
+ } else if (cachefiles_has_space(cache, 0, 1) == 0) {
+ /* there's space in the cache we can use */
+ fscache_mark_page_cached(op, page);
+ fscache_retrieval_complete(op, 1);
+ ret = -ENODATA;
+ } else {
+ goto enobufs;
+ }
+
+ _leave(" = %d", ret);
+ return ret;
+
+enobufs:
+ fscache_retrieval_complete(op, 1);
+ _leave(" = -ENOBUFS");
+ return -ENOBUFS;
+}
+
+/*
+ * read the corresponding pages to the given set from the backing file
+ * - any uncertain pages are simply discarded, to be tried again another time
+ */
+static int cachefiles_read_backing_file(struct cachefiles_object *object,
+ struct fscache_retrieval *op,
+ struct list_head *list)
+{
+ struct cachefiles_one_read *monitor = NULL;
+ struct address_space *bmapping = d_backing_inode(object->backer)->i_mapping;
+ struct page *newpage = NULL, *netpage, *_n, *backpage = NULL;
+ int ret = 0;
+
+ _enter("");
+
+ list_for_each_entry_safe(netpage, _n, list, lru) {
+ list_del(&netpage->lru);
+
+ _debug("read back %p{%lu,%d}",
+ netpage, netpage->index, page_count(netpage));
+
+ if (!monitor) {
+ monitor = kzalloc(sizeof(*monitor), cachefiles_gfp);
+ if (!monitor)
+ goto nomem;
+
+ monitor->op = fscache_get_retrieval(op);
+ init_waitqueue_func_entry(&monitor->monitor,
+ cachefiles_read_waiter);
+ }
+
+ for (;;) {
+ backpage = find_get_page(bmapping, netpage->index);
+ if (backpage)
+ goto backing_page_already_present;
+
+ if (!newpage) {
+ newpage = __page_cache_alloc(cachefiles_gfp);
+ if (!newpage)
+ goto nomem;
+ }
+
+ ret = add_to_page_cache_lru(newpage, bmapping,
+ netpage->index,
+ cachefiles_gfp);
+ if (ret == 0)
+ goto installed_new_backing_page;
+ if (ret != -EEXIST)
+ goto nomem;
+ }
+
+ /* we've installed a new backing page, so now we need
+ * to start it reading */
+ installed_new_backing_page:
+ _debug("- new %p", newpage);
+
+ backpage = newpage;
+ newpage = NULL;
+
+ reread_backing_page:
+ ret = bmapping->a_ops->readpage(NULL, backpage);
+ if (ret < 0)
+ goto read_error;
+
+ /* add the netfs page to the pagecache and LRU, and set the
+ * monitor to transfer the data across */
+ monitor_backing_page:
+ _debug("- monitor add");
+
+ ret = add_to_page_cache_lru(netpage, op->mapping,
+ netpage->index, cachefiles_gfp);
+ if (ret < 0) {
+ if (ret == -EEXIST) {
+ put_page(backpage);
+ backpage = NULL;
+ put_page(netpage);
+ netpage = NULL;
+ fscache_retrieval_complete(op, 1);
+ continue;
+ }
+ goto nomem;
+ }
+
+ /* install a monitor */
+ get_page(netpage);
+ monitor->netfs_page = netpage;
+
+ get_page(backpage);
+ monitor->back_page = backpage;
+ monitor->monitor.private = backpage;
+ add_page_wait_queue(backpage, &monitor->monitor);
+ monitor = NULL;
+
+ /* but the page may have been read before the monitor was
+ * installed, so the monitor may miss the event - so we have to
+ * ensure that we do get one in such a case */
+ if (trylock_page(backpage)) {
+ _debug("2unlock %p {%lx}", backpage, backpage->flags);
+ unlock_page(backpage);
+ }
+
+ put_page(backpage);
+ backpage = NULL;
+
+ put_page(netpage);
+ netpage = NULL;
+ continue;
+
+ /* if the backing page is already present, it can be in one of
+ * three states: read in progress, read failed or read okay */
+ backing_page_already_present:
+ _debug("- present %p", backpage);
+
+ if (PageError(backpage))
+ goto io_error;
+
+ if (PageUptodate(backpage))
+ goto backing_page_already_uptodate;
+
+ _debug("- not ready %p{%lx}", backpage, backpage->flags);
+
+ if (!trylock_page(backpage))
+ goto monitor_backing_page;
+
+ if (PageError(backpage)) {
+ _debug("error %lx", backpage->flags);
+ unlock_page(backpage);
+ goto io_error;
+ }
+
+ if (PageUptodate(backpage))
+ goto backing_page_already_uptodate_unlock;
+
+ /* we've locked a page that's neither up to date nor erroneous,
+ * so we need to attempt to read it again */
+ goto reread_backing_page;
+
+ /* the backing page is already up to date, attach the netfs
+ * page to the pagecache and LRU and copy the data across */
+ backing_page_already_uptodate_unlock:
+ _debug("uptodate %lx", backpage->flags);
+ unlock_page(backpage);
+ backing_page_already_uptodate:
+ _debug("- uptodate");
+
+ ret = add_to_page_cache_lru(netpage, op->mapping,
+ netpage->index, cachefiles_gfp);
+ if (ret < 0) {
+ if (ret == -EEXIST) {
+ put_page(backpage);
+ backpage = NULL;
+ put_page(netpage);
+ netpage = NULL;
+ fscache_retrieval_complete(op, 1);
+ continue;
+ }
+ goto nomem;
+ }
+
+ copy_highpage(netpage, backpage);
+
+ put_page(backpage);
+ backpage = NULL;
+
+ fscache_mark_page_cached(op, netpage);
+
+ /* the netpage is unlocked and marked up to date here */
+ fscache_end_io(op, netpage, 0);
+ put_page(netpage);
+ netpage = NULL;
+ fscache_retrieval_complete(op, 1);
+ continue;
+ }
+
+ netpage = NULL;
+
+ _debug("out");
+
+out:
+ /* tidy up */
+ if (newpage)
+ put_page(newpage);
+ if (netpage)
+ put_page(netpage);
+ if (backpage)
+ put_page(backpage);
+ if (monitor) {
+ fscache_put_retrieval(op);
+ kfree(monitor);
+ }
+
+ list_for_each_entry_safe(netpage, _n, list, lru) {
+ list_del(&netpage->lru);
+ put_page(netpage);
+ fscache_retrieval_complete(op, 1);
+ }
+
+ _leave(" = %d", ret);
+ return ret;
+
+nomem:
+ _debug("nomem");
+ ret = -ENOMEM;
+ goto record_page_complete;
+
+read_error:
+ _debug("read error %d", ret);
+ if (ret == -ENOMEM)
+ goto record_page_complete;
+io_error:
+ cachefiles_io_error_obj(object, "Page read error on backing file");
+ ret = -ENOBUFS;
+record_page_complete:
+ fscache_retrieval_complete(op, 1);
+ goto out;
+}
+
+/*
+ * read a list of pages from the cache or allocate blocks in which to store
+ * them
+ */
+int cachefiles_read_or_alloc_pages(struct fscache_retrieval *op,
+ struct list_head *pages,
+ unsigned *nr_pages,
+ gfp_t gfp)
+{
+ struct cachefiles_object *object;
+ struct cachefiles_cache *cache;
+ struct list_head backpages;
+ struct pagevec pagevec;
+ struct inode *inode;
+ struct page *page, *_n;
+ unsigned shift, nrbackpages;
+ int ret, ret2, space;
+
+ object = container_of(op->op.object,
+ struct cachefiles_object, fscache);
+ cache = container_of(object->fscache.cache,
+ struct cachefiles_cache, cache);
+
+ _enter("{OBJ%x,%d},,%d,,",
+ object->fscache.debug_id, atomic_read(&op->op.usage),
+ *nr_pages);
+
+ if (!object->backer)
+ goto all_enobufs;
+
+ space = 1;
+ if (cachefiles_has_space(cache, 0, *nr_pages) < 0)
+ space = 0;
+
+ inode = d_backing_inode(object->backer);
+ ASSERT(S_ISREG(inode->i_mode));
+ ASSERT(inode->i_mapping->a_ops->bmap);
+ ASSERT(inode->i_mapping->a_ops->readpages);
+
+ /* calculate the shift required to use bmap */
+ shift = PAGE_SHIFT - inode->i_sb->s_blocksize_bits;
+
+ pagevec_init(&pagevec);
+
+ op->op.flags &= FSCACHE_OP_KEEP_FLAGS;
+ op->op.flags |= FSCACHE_OP_ASYNC;
+ op->op.processor = cachefiles_read_copier;
+
+ INIT_LIST_HEAD(&backpages);
+ nrbackpages = 0;
+
+ ret = space ? -ENODATA : -ENOBUFS;
+ list_for_each_entry_safe(page, _n, pages, lru) {
+ sector_t block0, block;
+
+ /* we assume the absence or presence of the first block is a
+ * good enough indication for the page as a whole
+ * - TODO: don't use bmap() for this as it is _not_ actually
+ * good enough for this as it doesn't indicate errors, but
+ * it's all we've got for the moment
+ */
+ block0 = page->index;
+ block0 <<= shift;
+
+ block = inode->i_mapping->a_ops->bmap(inode->i_mapping,
+ block0);
+ _debug("%llx -> %llx",
+ (unsigned long long) block0,
+ (unsigned long long) block);
+
+ if (block) {
+ /* we have data - add it to the list to give to the
+ * backing fs */
+ list_move(&page->lru, &backpages);
+ (*nr_pages)--;
+ nrbackpages++;
+ } else if (space && pagevec_add(&pagevec, page) == 0) {
+ fscache_mark_pages_cached(op, &pagevec);
+ fscache_retrieval_complete(op, 1);
+ ret = -ENODATA;
+ } else {
+ fscache_retrieval_complete(op, 1);
+ }
+ }
+
+ if (pagevec_count(&pagevec) > 0)
+ fscache_mark_pages_cached(op, &pagevec);
+
+ if (list_empty(pages))
+ ret = 0;
+
+ /* submit the apparently valid pages to the backing fs to be read from
+ * disk */
+ if (nrbackpages > 0) {
+ ret2 = cachefiles_read_backing_file(object, op, &backpages);
+ if (ret2 == -ENOMEM || ret2 == -EINTR)
+ ret = ret2;
+ }
+
+ _leave(" = %d [nr=%u%s]",
+ ret, *nr_pages, list_empty(pages) ? " empty" : "");
+ return ret;
+
+all_enobufs:
+ fscache_retrieval_complete(op, *nr_pages);
+ return -ENOBUFS;
+}
+
+/*
+ * allocate a block in the cache in which to store a page
+ * - cache withdrawal is prevented by the caller
+ * - returns -EINTR if interrupted
+ * - returns -ENOMEM if ran out of memory
+ * - returns -ENOBUFS if no buffers can be made available
+ * - returns -ENOBUFS if page is beyond EOF
+ * - otherwise:
+ * - the metadata will be retained
+ * - 0 will be returned
+ */
+int cachefiles_allocate_page(struct fscache_retrieval *op,
+ struct page *page,
+ gfp_t gfp)
+{
+ struct cachefiles_object *object;
+ struct cachefiles_cache *cache;
+ int ret;
+
+ object = container_of(op->op.object,
+ struct cachefiles_object, fscache);
+ cache = container_of(object->fscache.cache,
+ struct cachefiles_cache, cache);
+
+ _enter("%p,{%lx},", object, page->index);
+
+ ret = cachefiles_has_space(cache, 0, 1);
+ if (ret == 0)
+ fscache_mark_page_cached(op, page);
+ else
+ ret = -ENOBUFS;
+
+ fscache_retrieval_complete(op, 1);
+ _leave(" = %d", ret);
+ return ret;
+}
+
+/*
+ * allocate blocks in the cache in which to store a set of pages
+ * - cache withdrawal is prevented by the caller
+ * - returns -EINTR if interrupted
+ * - returns -ENOMEM if ran out of memory
+ * - returns -ENOBUFS if some buffers couldn't be made available
+ * - returns -ENOBUFS if some pages are beyond EOF
+ * - otherwise:
+ * - -ENODATA will be returned
+ * - metadata will be retained for any page marked
+ */
+int cachefiles_allocate_pages(struct fscache_retrieval *op,
+ struct list_head *pages,
+ unsigned *nr_pages,
+ gfp_t gfp)
+{
+ struct cachefiles_object *object;
+ struct cachefiles_cache *cache;
+ struct pagevec pagevec;
+ struct page *page;
+ int ret;
+
+ object = container_of(op->op.object,
+ struct cachefiles_object, fscache);
+ cache = container_of(object->fscache.cache,
+ struct cachefiles_cache, cache);
+
+ _enter("%p,,,%d,", object, *nr_pages);
+
+ ret = cachefiles_has_space(cache, 0, *nr_pages);
+ if (ret == 0) {
+ pagevec_init(&pagevec);
+
+ list_for_each_entry(page, pages, lru) {
+ if (pagevec_add(&pagevec, page) == 0)
+ fscache_mark_pages_cached(op, &pagevec);
+ }
+
+ if (pagevec_count(&pagevec) > 0)
+ fscache_mark_pages_cached(op, &pagevec);
+ ret = -ENODATA;
+ } else {
+ ret = -ENOBUFS;
+ }
+
+ fscache_retrieval_complete(op, *nr_pages);
+ _leave(" = %d", ret);
+ return ret;
+}
+
+/*
+ * request a page be stored in the cache
+ * - cache withdrawal is prevented by the caller
+ * - this request may be ignored if there's no cache block available, in which
+ * case -ENOBUFS will be returned
+ * - if the op is in progress, 0 will be returned
+ */
+int cachefiles_write_page(struct fscache_storage *op, struct page *page)
+{
+ struct cachefiles_object *object;
+ struct cachefiles_cache *cache;
+ struct file *file;
+ struct path path;
+ loff_t pos, eof;
+ size_t len;
+ void *data;
+ int ret = -ENOBUFS;
+
+ ASSERT(op != NULL);
+ ASSERT(page != NULL);
+
+ object = container_of(op->op.object,
+ struct cachefiles_object, fscache);
+
+ _enter("%p,%p{%lx},,,", object, page, page->index);
+
+ if (!object->backer) {
+ _leave(" = -ENOBUFS");
+ return -ENOBUFS;
+ }
+
+ ASSERT(d_is_reg(object->backer));
+
+ cache = container_of(object->fscache.cache,
+ struct cachefiles_cache, cache);
+
+ pos = (loff_t)page->index << PAGE_SHIFT;
+
+ /* We mustn't write more data than we have, so we have to beware of a
+ * partial page at EOF.
+ */
+ eof = object->fscache.store_limit_l;
+ if (pos >= eof)
+ goto error;
+
+ /* write the page to the backing filesystem and let it store it in its
+ * own time */
+ path.mnt = cache->mnt;
+ path.dentry = object->backer;
+ file = dentry_open(&path, O_RDWR | O_LARGEFILE, cache->cache_cred);
+ if (IS_ERR(file)) {
+ ret = PTR_ERR(file);
+ goto error_2;
+ }
+
+ len = PAGE_SIZE;
+ if (eof & ~PAGE_MASK) {
+ if (eof - pos < PAGE_SIZE) {
+ _debug("cut short %llx to %llx",
+ pos, eof);
+ len = eof - pos;
+ ASSERTCMP(pos + len, ==, eof);
+ }
+ }
+
+ data = kmap(page);
+ ret = __kernel_write(file, data, len, &pos);
+ kunmap(page);
+ fput(file);
+ if (ret != len)
+ goto error_eio;
+
+ _leave(" = 0");
+ return 0;
+
+error_eio:
+ ret = -EIO;
+error_2:
+ if (ret == -EIO)
+ cachefiles_io_error_obj(object,
+ "Write page to backing file failed");
+error:
+ _leave(" = -ENOBUFS [%d]", ret);
+ return -ENOBUFS;
+}
+
+/*
+ * detach a backing block from a page
+ * - cache withdrawal is prevented by the caller
+ */
+void cachefiles_uncache_page(struct fscache_object *_object, struct page *page)
+ __releases(&object->fscache.cookie->lock)
+{
+ struct cachefiles_object *object;
+
+ object = container_of(_object, struct cachefiles_object, fscache);
+
+ _enter("%p,{%lu}", object, page->index);
+
+ spin_unlock(&object->fscache.cookie->lock);
+}
diff --git a/fs/cachefiles/security.c b/fs/cachefiles/security.c
new file mode 100644
index 0000000..31bbc05
--- /dev/null
+++ b/fs/cachefiles/security.c
@@ -0,0 +1,116 @@
+/* CacheFiles security management
+ *
+ * Copyright (C) 2007 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/fs.h>
+#include <linux/cred.h>
+#include "internal.h"
+
+/*
+ * determine the security context within which we access the cache from within
+ * the kernel
+ */
+int cachefiles_get_security_ID(struct cachefiles_cache *cache)
+{
+ struct cred *new;
+ int ret;
+
+ _enter("{%s}", cache->secctx);
+
+ new = prepare_kernel_cred(current);
+ if (!new) {
+ ret = -ENOMEM;
+ goto error;
+ }
+
+ if (cache->secctx) {
+ ret = set_security_override_from_ctx(new, cache->secctx);
+ if (ret < 0) {
+ put_cred(new);
+ pr_err("Security denies permission to nominate security context: error %d\n",
+ ret);
+ goto error;
+ }
+ }
+
+ cache->cache_cred = new;
+ ret = 0;
+error:
+ _leave(" = %d", ret);
+ return ret;
+}
+
+/*
+ * see if mkdir and create can be performed in the root directory
+ */
+static int cachefiles_check_cache_dir(struct cachefiles_cache *cache,
+ struct dentry *root)
+{
+ int ret;
+
+ ret = security_inode_mkdir(d_backing_inode(root), root, 0);
+ if (ret < 0) {
+ pr_err("Security denies permission to make dirs: error %d",
+ ret);
+ return ret;
+ }
+
+ ret = security_inode_create(d_backing_inode(root), root, 0);
+ if (ret < 0)
+ pr_err("Security denies permission to create files: error %d",
+ ret);
+
+ return ret;
+}
+
+/*
+ * check the security details of the on-disk cache
+ * - must be called with security override in force
+ * - must return with a security override in force - even in the case of an
+ * error
+ */
+int cachefiles_determine_cache_security(struct cachefiles_cache *cache,
+ struct dentry *root,
+ const struct cred **_saved_cred)
+{
+ struct cred *new;
+ int ret;
+
+ _enter("");
+
+ /* duplicate the cache creds for COW (the override is currently in
+ * force, so we can use prepare_creds() to do this) */
+ new = prepare_creds();
+ if (!new)
+ return -ENOMEM;
+
+ cachefiles_end_secure(cache, *_saved_cred);
+
+ /* use the cache root dir's security context as the basis with
+ * which create files */
+ ret = set_create_files_as(new, d_backing_inode(root));
+ if (ret < 0) {
+ abort_creds(new);
+ cachefiles_begin_secure(cache, _saved_cred);
+ _leave(" = %d [cfa]", ret);
+ return ret;
+ }
+
+ put_cred(cache->cache_cred);
+ cache->cache_cred = new;
+
+ cachefiles_begin_secure(cache, _saved_cred);
+ ret = cachefiles_check_cache_dir(cache, root);
+
+ if (ret == -EOPNOTSUPP)
+ ret = 0;
+ _leave(" = %d", ret);
+ return ret;
+}
diff --git a/fs/cachefiles/xattr.c b/fs/cachefiles/xattr.c
new file mode 100644
index 0000000..511e6c6
--- /dev/null
+++ b/fs/cachefiles/xattr.c
@@ -0,0 +1,329 @@
+/* CacheFiles extended attribute management
+ *
+ * Copyright (C) 2007 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>
+#include <linux/sched.h>
+#include <linux/file.h>
+#include <linux/fs.h>
+#include <linux/fsnotify.h>
+#include <linux/quotaops.h>
+#include <linux/xattr.h>
+#include <linux/slab.h>
+#include "internal.h"
+
+static const char cachefiles_xattr_cache[] =
+ XATTR_USER_PREFIX "CacheFiles.cache";
+
+/*
+ * check the type label on an object
+ * - done using xattrs
+ */
+int cachefiles_check_object_type(struct cachefiles_object *object)
+{
+ struct dentry *dentry = object->dentry;
+ char type[3], xtype[3];
+ int ret;
+
+ ASSERT(dentry);
+ ASSERT(d_backing_inode(dentry));
+
+ if (!object->fscache.cookie)
+ strcpy(type, "C3");
+ else
+ snprintf(type, 3, "%02x", object->fscache.cookie->def->type);
+
+ _enter("%p{%s}", object, type);
+
+ /* attempt to install a type label directly */
+ ret = vfs_setxattr(dentry, cachefiles_xattr_cache, type, 2,
+ XATTR_CREATE);
+ if (ret == 0) {
+ _debug("SET"); /* we succeeded */
+ goto error;
+ }
+
+ if (ret != -EEXIST) {
+ pr_err("Can't set xattr on %pd [%lu] (err %d)\n",
+ dentry, d_backing_inode(dentry)->i_ino,
+ -ret);
+ goto error;
+ }
+
+ /* read the current type label */
+ ret = vfs_getxattr(dentry, cachefiles_xattr_cache, xtype, 3);
+ if (ret < 0) {
+ if (ret == -ERANGE)
+ goto bad_type_length;
+
+ pr_err("Can't read xattr on %pd [%lu] (err %d)\n",
+ dentry, d_backing_inode(dentry)->i_ino,
+ -ret);
+ goto error;
+ }
+
+ /* check the type is what we're expecting */
+ if (ret != 2)
+ goto bad_type_length;
+
+ if (xtype[0] != type[0] || xtype[1] != type[1])
+ goto bad_type;
+
+ ret = 0;
+
+error:
+ _leave(" = %d", ret);
+ return ret;
+
+bad_type_length:
+ pr_err("Cache object %lu type xattr length incorrect\n",
+ d_backing_inode(dentry)->i_ino);
+ ret = -EIO;
+ goto error;
+
+bad_type:
+ xtype[2] = 0;
+ pr_err("Cache object %pd [%lu] type %s not %s\n",
+ dentry, d_backing_inode(dentry)->i_ino,
+ xtype, type);
+ ret = -EIO;
+ goto error;
+}
+
+/*
+ * set the state xattr on a cache file
+ */
+int cachefiles_set_object_xattr(struct cachefiles_object *object,
+ struct cachefiles_xattr *auxdata)
+{
+ struct dentry *dentry = object->dentry;
+ int ret;
+
+ ASSERT(dentry);
+
+ _enter("%p,#%d", object, auxdata->len);
+
+ /* attempt to install the cache metadata directly */
+ _debug("SET #%u", auxdata->len);
+
+ clear_bit(FSCACHE_COOKIE_AUX_UPDATED, &object->fscache.cookie->flags);
+ ret = vfs_setxattr(dentry, cachefiles_xattr_cache,
+ &auxdata->type, auxdata->len,
+ XATTR_CREATE);
+ if (ret < 0 && ret != -ENOMEM)
+ cachefiles_io_error_obj(
+ object,
+ "Failed to set xattr with error %d", ret);
+
+ _leave(" = %d", ret);
+ return ret;
+}
+
+/*
+ * update the state xattr on a cache file
+ */
+int cachefiles_update_object_xattr(struct cachefiles_object *object,
+ struct cachefiles_xattr *auxdata)
+{
+ struct dentry *dentry = object->dentry;
+ int ret;
+
+ if (!dentry)
+ return -ESTALE;
+
+ _enter("%p,#%d", object, auxdata->len);
+
+ /* attempt to install the cache metadata directly */
+ _debug("SET #%u", auxdata->len);
+
+ clear_bit(FSCACHE_COOKIE_AUX_UPDATED, &object->fscache.cookie->flags);
+ ret = vfs_setxattr(dentry, cachefiles_xattr_cache,
+ &auxdata->type, auxdata->len,
+ XATTR_REPLACE);
+ if (ret < 0 && ret != -ENOMEM)
+ cachefiles_io_error_obj(
+ object,
+ "Failed to update xattr with error %d", ret);
+
+ _leave(" = %d", ret);
+ return ret;
+}
+
+/*
+ * check the consistency between the backing cache and the FS-Cache cookie
+ */
+int cachefiles_check_auxdata(struct cachefiles_object *object)
+{
+ struct cachefiles_xattr *auxbuf;
+ enum fscache_checkaux validity;
+ struct dentry *dentry = object->dentry;
+ ssize_t xlen;
+ int ret;
+
+ ASSERT(dentry);
+ ASSERT(d_backing_inode(dentry));
+ ASSERT(object->fscache.cookie->def->check_aux);
+
+ auxbuf = kmalloc(sizeof(struct cachefiles_xattr) + 512, GFP_KERNEL);
+ if (!auxbuf)
+ return -ENOMEM;
+
+ xlen = vfs_getxattr(dentry, cachefiles_xattr_cache,
+ &auxbuf->type, 512 + 1);
+ ret = -ESTALE;
+ if (xlen < 1 ||
+ auxbuf->type != object->fscache.cookie->def->type)
+ goto error;
+
+ xlen--;
+ validity = fscache_check_aux(&object->fscache, &auxbuf->data, xlen,
+ i_size_read(d_backing_inode(dentry)));
+ if (validity != FSCACHE_CHECKAUX_OKAY)
+ goto error;
+
+ ret = 0;
+error:
+ kfree(auxbuf);
+ return ret;
+}
+
+/*
+ * check the state xattr on a cache file
+ * - return -ESTALE if the object should be deleted
+ */
+int cachefiles_check_object_xattr(struct cachefiles_object *object,
+ struct cachefiles_xattr *auxdata)
+{
+ struct cachefiles_xattr *auxbuf;
+ struct dentry *dentry = object->dentry;
+ int ret;
+
+ _enter("%p,#%d", object, auxdata->len);
+
+ ASSERT(dentry);
+ ASSERT(d_backing_inode(dentry));
+
+ auxbuf = kmalloc(sizeof(struct cachefiles_xattr) + 512, cachefiles_gfp);
+ if (!auxbuf) {
+ _leave(" = -ENOMEM");
+ return -ENOMEM;
+ }
+
+ /* read the current type label */
+ ret = vfs_getxattr(dentry, cachefiles_xattr_cache,
+ &auxbuf->type, 512 + 1);
+ if (ret < 0) {
+ if (ret == -ENODATA)
+ goto stale; /* no attribute - power went off
+ * mid-cull? */
+
+ if (ret == -ERANGE)
+ goto bad_type_length;
+
+ cachefiles_io_error_obj(object,
+ "Can't read xattr on %lu (err %d)",
+ d_backing_inode(dentry)->i_ino, -ret);
+ goto error;
+ }
+
+ /* check the on-disk object */
+ if (ret < 1)
+ goto bad_type_length;
+
+ if (auxbuf->type != auxdata->type)
+ goto stale;
+
+ auxbuf->len = ret;
+
+ /* consult the netfs */
+ if (object->fscache.cookie->def->check_aux) {
+ enum fscache_checkaux result;
+ unsigned int dlen;
+
+ dlen = auxbuf->len - 1;
+
+ _debug("checkaux %s #%u",
+ object->fscache.cookie->def->name, dlen);
+
+ result = fscache_check_aux(&object->fscache,
+ &auxbuf->data, dlen,
+ i_size_read(d_backing_inode(dentry)));
+
+ switch (result) {
+ /* entry okay as is */
+ case FSCACHE_CHECKAUX_OKAY:
+ goto okay;
+
+ /* entry requires update */
+ case FSCACHE_CHECKAUX_NEEDS_UPDATE:
+ break;
+
+ /* entry requires deletion */
+ case FSCACHE_CHECKAUX_OBSOLETE:
+ goto stale;
+
+ default:
+ BUG();
+ }
+
+ /* update the current label */
+ ret = vfs_setxattr(dentry, cachefiles_xattr_cache,
+ &auxdata->type, auxdata->len,
+ XATTR_REPLACE);
+ if (ret < 0) {
+ cachefiles_io_error_obj(object,
+ "Can't update xattr on %lu"
+ " (error %d)",
+ d_backing_inode(dentry)->i_ino, -ret);
+ goto error;
+ }
+ }
+
+okay:
+ ret = 0;
+
+error:
+ kfree(auxbuf);
+ _leave(" = %d", ret);
+ return ret;
+
+bad_type_length:
+ pr_err("Cache object %lu xattr length incorrect\n",
+ d_backing_inode(dentry)->i_ino);
+ ret = -EIO;
+ goto error;
+
+stale:
+ ret = -ESTALE;
+ goto error;
+}
+
+/*
+ * remove the object's xattr to mark it stale
+ */
+int cachefiles_remove_object_xattr(struct cachefiles_cache *cache,
+ struct dentry *dentry)
+{
+ int ret;
+
+ ret = vfs_removexattr(dentry, cachefiles_xattr_cache);
+ if (ret < 0) {
+ if (ret == -ENOENT || ret == -ENODATA)
+ ret = 0;
+ else if (ret != -ENOMEM)
+ cachefiles_io_error(cache,
+ "Can't remove xattr from %lu"
+ " (error %d)",
+ d_backing_inode(dentry)->i_ino, -ret);
+ }
+
+ _leave(" = %d", ret);
+ return ret;
+}