--- /dev/null
+/*
+ FUSE: Filesystem in Userspace
+ Copyright (C) 2001-2008 Miklos Szeredi <miklos@szeredi.hu>
+
+ This program can be distributed under the terms of the GNU GPL.
+ See the file COPYING.
+*/
+
+#include "fuse_i.h"
+
+#include <linux/pagemap.h>
+#include <linux/slab.h>
+#include <linux/file.h>
+#include <linux/seq_file.h>
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/parser.h>
+#include <linux/statfs.h>
+#include <linux/random.h>
+#include <linux/sched.h>
+#include <linux/exportfs.h>
+
+MODULE_AUTHOR("Miklos Szeredi <miklos@szeredi.hu>");
+MODULE_DESCRIPTION("Filesystem in Userspace");
+MODULE_LICENSE("GPL");
+
+static struct kmem_cache *fuse_inode_cachep;
+struct list_head fuse_conn_list;
+DEFINE_MUTEX(fuse_mutex);
+
+static int set_global_limit(const char *val, struct kernel_param *kp);
+
+unsigned max_user_bgreq;
+module_param_call(max_user_bgreq, set_global_limit, param_get_uint,
+ &max_user_bgreq, 0644);
+__MODULE_PARM_TYPE(max_user_bgreq, "uint");
+MODULE_PARM_DESC(max_user_bgreq,
+ "Global limit for the maximum number of backgrounded requests an "
+ "unprivileged user can set");
+
+unsigned max_user_congthresh;
+module_param_call(max_user_congthresh, set_global_limit, param_get_uint,
+ &max_user_congthresh, 0644);
+__MODULE_PARM_TYPE(max_user_congthresh, "uint");
+MODULE_PARM_DESC(max_user_congthresh,
+ "Global limit for the maximum congestion threshold an "
+ "unprivileged user can set");
+
+#define FUSE_SUPER_MAGIC 0x65735546
+
+#define FUSE_DEFAULT_BLKSIZE 512
+
+/** Maximum number of outstanding background requests */
+#define FUSE_DEFAULT_MAX_BACKGROUND 12
+
+/** Congestion starts at 75% of maximum */
+#define FUSE_DEFAULT_CONGESTION_THRESHOLD (FUSE_DEFAULT_MAX_BACKGROUND * 3 / 4)
+
+struct fuse_mount_data {
+ int fd;
+ unsigned rootmode;
+ kuid_t user_id;
+ kgid_t group_id;
+ unsigned fd_present:1;
+ unsigned rootmode_present:1;
+ unsigned user_id_present:1;
+ unsigned group_id_present:1;
+ unsigned flags;
+ unsigned max_read;
+ unsigned blksize;
+};
+
+struct fuse_forget_link *fuse_alloc_forget(void)
+{
+ return kzalloc(sizeof(struct fuse_forget_link), GFP_KERNEL);
+}
+
+static struct inode *fuse_alloc_inode(struct super_block *sb)
+{
+ struct inode *inode;
+ struct fuse_inode *fi;
+
+ inode = kmem_cache_alloc(fuse_inode_cachep, GFP_KERNEL);
+ if (!inode)
+ return NULL;
+
+ fi = get_fuse_inode(inode);
+ fi->i_time = 0;
+ fi->nodeid = 0;
+ fi->nlookup = 0;
+ fi->attr_version = 0;
+ fi->writectr = 0;
+ fi->orig_ino = 0;
+ fi->state = 0;
+ INIT_LIST_HEAD(&fi->write_files);
+ INIT_LIST_HEAD(&fi->queued_writes);
+ INIT_LIST_HEAD(&fi->writepages);
+ init_waitqueue_head(&fi->page_waitq);
+ fi->forget = fuse_alloc_forget();
+ if (!fi->forget) {
+ kmem_cache_free(fuse_inode_cachep, inode);
+ return NULL;
+ }
+
+ return inode;
+}
+
+static void fuse_i_callback(struct rcu_head *head)
+{
+ struct inode *inode = container_of(head, struct inode, i_rcu);
+ kmem_cache_free(fuse_inode_cachep, inode);
+}
+
+static void fuse_destroy_inode(struct inode *inode)
+{
+ struct fuse_inode *fi = get_fuse_inode(inode);
+ BUG_ON(!list_empty(&fi->write_files));
+ BUG_ON(!list_empty(&fi->queued_writes));
+ kfree(fi->forget);
+ call_rcu(&inode->i_rcu, fuse_i_callback);
+}
+
+static void fuse_evict_inode(struct inode *inode)
+{
+ truncate_inode_pages_final(&inode->i_data);
+ clear_inode(inode);
+ if (inode->i_sb->s_flags & MS_ACTIVE) {
+ struct fuse_conn *fc = get_fuse_conn(inode);
+ struct fuse_inode *fi = get_fuse_inode(inode);
+ fuse_queue_forget(fc, fi->forget, fi->nodeid, fi->nlookup);
+ fi->forget = NULL;
+ }
+}
+
+static int fuse_remount_fs(struct super_block *sb, int *flags, char *data)
+{
+ sync_filesystem(sb);
+ if (*flags & MS_MANDLOCK)
+ return -EINVAL;
+
+ return 0;
+}
+
+/*
+ * ino_t is 32-bits on 32-bit arch. We have to squash the 64-bit value down
+ * so that it will fit.
+ */
+static ino_t fuse_squash_ino(u64 ino64)
+{
+ ino_t ino = (ino_t) ino64;
+ if (sizeof(ino_t) < sizeof(u64))
+ ino ^= ino64 >> (sizeof(u64) - sizeof(ino_t)) * 8;
+ return ino;
+}
+
+void fuse_change_attributes_common(struct inode *inode, struct fuse_attr *attr,
+ u64 attr_valid)
+{
+ struct fuse_conn *fc = get_fuse_conn(inode);
+ struct fuse_inode *fi = get_fuse_inode(inode);
+
+ fi->attr_version = ++fc->attr_version;
+ fi->i_time = attr_valid;
+
+ inode->i_ino = fuse_squash_ino(attr->ino);
+ inode->i_mode = (inode->i_mode & S_IFMT) | (attr->mode & 07777);
+ set_nlink(inode, attr->nlink);
+ inode->i_uid = make_kuid(&init_user_ns, attr->uid);
+ inode->i_gid = make_kgid(&init_user_ns, attr->gid);
+ inode->i_blocks = attr->blocks;
+ inode->i_atime.tv_sec = attr->atime;
+ inode->i_atime.tv_nsec = attr->atimensec;
+ /* mtime from server may be stale due to local buffered write */
+ if (!fc->writeback_cache || !S_ISREG(inode->i_mode)) {
+ inode->i_mtime.tv_sec = attr->mtime;
+ inode->i_mtime.tv_nsec = attr->mtimensec;
+ inode->i_ctime.tv_sec = attr->ctime;
+ inode->i_ctime.tv_nsec = attr->ctimensec;
+ }
+
+ if (attr->blksize != 0)
+ inode->i_blkbits = ilog2(attr->blksize);
+ else
+ inode->i_blkbits = inode->i_sb->s_blocksize_bits;
+
+ /*
+ * Don't set the sticky bit in i_mode, unless we want the VFS
+ * to check permissions. This prevents failures due to the
+ * check in may_delete().
+ */
+ fi->orig_i_mode = inode->i_mode;
+ if (!(fc->flags & FUSE_DEFAULT_PERMISSIONS))
+ inode->i_mode &= ~S_ISVTX;
+
+ fi->orig_ino = attr->ino;
+}
+
+void fuse_change_attributes(struct inode *inode, struct fuse_attr *attr,
+ u64 attr_valid, u64 attr_version)
+{
+ struct fuse_conn *fc = get_fuse_conn(inode);
+ struct fuse_inode *fi = get_fuse_inode(inode);
+ bool is_wb = fc->writeback_cache;
+ loff_t oldsize;
+ struct timespec old_mtime;
+
+ spin_lock(&fc->lock);
+ if ((attr_version != 0 && fi->attr_version > attr_version) ||
+ test_bit(FUSE_I_SIZE_UNSTABLE, &fi->state)) {
+ spin_unlock(&fc->lock);
+ return;
+ }
+
+ old_mtime = inode->i_mtime;
+ fuse_change_attributes_common(inode, attr, attr_valid);
+
+ oldsize = inode->i_size;
+ /*
+ * In case of writeback_cache enabled, the cached writes beyond EOF
+ * extend local i_size without keeping userspace server in sync. So,
+ * attr->size coming from server can be stale. We cannot trust it.
+ */
+ if (!is_wb || !S_ISREG(inode->i_mode))
+ i_size_write(inode, attr->size);
+ spin_unlock(&fc->lock);
+
+ if (!is_wb && S_ISREG(inode->i_mode)) {
+ bool inval = false;
+
+ if (oldsize != attr->size) {
+ truncate_pagecache(inode, attr->size);
+ inval = true;
+ } else if (fc->auto_inval_data) {
+ struct timespec new_mtime = {
+ .tv_sec = attr->mtime,
+ .tv_nsec = attr->mtimensec,
+ };
+
+ /*
+ * Auto inval mode also checks and invalidates if mtime
+ * has changed.
+ */
+ if (!timespec_equal(&old_mtime, &new_mtime))
+ inval = true;
+ }
+
+ if (inval)
+ invalidate_inode_pages2(inode->i_mapping);
+ }
+}
+
+static void fuse_init_inode(struct inode *inode, struct fuse_attr *attr)
+{
+ inode->i_mode = attr->mode & S_IFMT;
+ inode->i_size = attr->size;
+ inode->i_mtime.tv_sec = attr->mtime;
+ inode->i_mtime.tv_nsec = attr->mtimensec;
+ inode->i_ctime.tv_sec = attr->ctime;
+ inode->i_ctime.tv_nsec = attr->ctimensec;
+ if (S_ISREG(inode->i_mode)) {
+ fuse_init_common(inode);
+ fuse_init_file_inode(inode);
+ } else if (S_ISDIR(inode->i_mode))
+ fuse_init_dir(inode);
+ else if (S_ISLNK(inode->i_mode))
+ fuse_init_symlink(inode);
+ else if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode) ||
+ S_ISFIFO(inode->i_mode) || S_ISSOCK(inode->i_mode)) {
+ fuse_init_common(inode);
+ init_special_inode(inode, inode->i_mode,
+ new_decode_dev(attr->rdev));
+ } else
+ BUG();
+}
+
+int fuse_inode_eq(struct inode *inode, void *_nodeidp)
+{
+ u64 nodeid = *(u64 *) _nodeidp;
+ if (get_node_id(inode) == nodeid)
+ return 1;
+ else
+ return 0;
+}
+
+static int fuse_inode_set(struct inode *inode, void *_nodeidp)
+{
+ u64 nodeid = *(u64 *) _nodeidp;
+ get_fuse_inode(inode)->nodeid = nodeid;
+ return 0;
+}
+
+struct inode *fuse_iget(struct super_block *sb, u64 nodeid,
+ int generation, struct fuse_attr *attr,
+ u64 attr_valid, u64 attr_version)
+{
+ struct inode *inode;
+ struct fuse_inode *fi;
+ struct fuse_conn *fc = get_fuse_conn_super(sb);
+
+ retry:
+ inode = iget5_locked(sb, nodeid, fuse_inode_eq, fuse_inode_set, &nodeid);
+ if (!inode)
+ return NULL;
+
+ if ((inode->i_state & I_NEW)) {
+ inode->i_flags |= S_NOATIME;
+ if (!fc->writeback_cache || !S_ISREG(attr->mode))
+ inode->i_flags |= S_NOCMTIME;
+ inode->i_generation = generation;
+ fuse_init_inode(inode, attr);
+ unlock_new_inode(inode);
+ } else if ((inode->i_mode ^ attr->mode) & S_IFMT) {
+ /* Inode has changed type, any I/O on the old should fail */
+ make_bad_inode(inode);
+ iput(inode);
+ goto retry;
+ }
+
+ fi = get_fuse_inode(inode);
+ spin_lock(&fc->lock);
+ fi->nlookup++;
+ spin_unlock(&fc->lock);
+ fuse_change_attributes(inode, attr, attr_valid, attr_version);
+
+ return inode;
+}
+
+int fuse_reverse_inval_inode(struct super_block *sb, u64 nodeid,
+ loff_t offset, loff_t len)
+{
+ struct inode *inode;
+ pgoff_t pg_start;
+ pgoff_t pg_end;
+
+ inode = ilookup5(sb, nodeid, fuse_inode_eq, &nodeid);
+ if (!inode)
+ return -ENOENT;
+
+ fuse_invalidate_attr(inode);
+ if (offset >= 0) {
+ pg_start = offset >> PAGE_CACHE_SHIFT;
+ if (len <= 0)
+ pg_end = -1;
+ else
+ pg_end = (offset + len - 1) >> PAGE_CACHE_SHIFT;
+ invalidate_inode_pages2_range(inode->i_mapping,
+ pg_start, pg_end);
+ }
+ iput(inode);
+ return 0;
+}
+
+static void fuse_umount_begin(struct super_block *sb)
+{
+ fuse_abort_conn(get_fuse_conn_super(sb));
+}
+
+static void fuse_send_destroy(struct fuse_conn *fc)
+{
+ struct fuse_req *req = fc->destroy_req;
+ if (req && fc->conn_init) {
+ fc->destroy_req = NULL;
+ req->in.h.opcode = FUSE_DESTROY;
+ req->force = 1;
+ req->background = 0;
+ fuse_request_send(fc, req);
+ fuse_put_request(fc, req);
+ }
+}
+
+static void fuse_bdi_destroy(struct fuse_conn *fc)
+{
+ if (fc->bdi_initialized)
+ bdi_destroy(&fc->bdi);
+}
+
+static void fuse_put_super(struct super_block *sb)
+{
+ struct fuse_conn *fc = get_fuse_conn_super(sb);
+
+ fuse_send_destroy(fc);
+
+ fuse_abort_conn(fc);
+ mutex_lock(&fuse_mutex);
+ list_del(&fc->entry);
+ fuse_ctl_remove_conn(fc);
+ mutex_unlock(&fuse_mutex);
+ fuse_bdi_destroy(fc);
+
+ fuse_conn_put(fc);
+}
+
+static void convert_fuse_statfs(struct kstatfs *stbuf, struct fuse_kstatfs *attr)
+{
+ stbuf->f_type = FUSE_SUPER_MAGIC;
+ stbuf->f_bsize = attr->bsize;
+ stbuf->f_frsize = attr->frsize;
+ stbuf->f_blocks = attr->blocks;
+ stbuf->f_bfree = attr->bfree;
+ stbuf->f_bavail = attr->bavail;
+ stbuf->f_files = attr->files;
+ stbuf->f_ffree = attr->ffree;
+ stbuf->f_namelen = attr->namelen;
+ /* fsid is left zero */
+}
+
+static int fuse_statfs(struct dentry *dentry, struct kstatfs *buf)
+{
+ struct super_block *sb = dentry->d_sb;
+ struct fuse_conn *fc = get_fuse_conn_super(sb);
+ FUSE_ARGS(args);
+ struct fuse_statfs_out outarg;
+ int err;
+
+ if (!fuse_allow_current_process(fc)) {
+ buf->f_type = FUSE_SUPER_MAGIC;
+ return 0;
+ }
+
+ memset(&outarg, 0, sizeof(outarg));
+ args.in.numargs = 0;
+ args.in.h.opcode = FUSE_STATFS;
+ args.in.h.nodeid = get_node_id(d_inode(dentry));
+ args.out.numargs = 1;
+ args.out.args[0].size = sizeof(outarg);
+ args.out.args[0].value = &outarg;
+ err = fuse_simple_request(fc, &args);
+ if (!err)
+ convert_fuse_statfs(buf, &outarg.st);
+ return err;
+}
+
+enum {
+ OPT_FD,
+ OPT_ROOTMODE,
+ OPT_USER_ID,
+ OPT_GROUP_ID,
+ OPT_DEFAULT_PERMISSIONS,
+ OPT_ALLOW_OTHER,
+ OPT_MAX_READ,
+ OPT_BLKSIZE,
+ OPT_ERR
+};
+
+static const match_table_t tokens = {
+ {OPT_FD, "fd=%u"},
+ {OPT_ROOTMODE, "rootmode=%o"},
+ {OPT_USER_ID, "user_id=%u"},
+ {OPT_GROUP_ID, "group_id=%u"},
+ {OPT_DEFAULT_PERMISSIONS, "default_permissions"},
+ {OPT_ALLOW_OTHER, "allow_other"},
+ {OPT_MAX_READ, "max_read=%u"},
+ {OPT_BLKSIZE, "blksize=%u"},
+ {OPT_ERR, NULL}
+};
+
+static int fuse_match_uint(substring_t *s, unsigned int *res)
+{
+ int err = -ENOMEM;
+ char *buf = match_strdup(s);
+ if (buf) {
+ err = kstrtouint(buf, 10, res);
+ kfree(buf);
+ }
+ return err;
+}
+
+static int parse_fuse_opt(char *opt, struct fuse_mount_data *d, int is_bdev)
+{
+ char *p;
+ memset(d, 0, sizeof(struct fuse_mount_data));
+ d->max_read = ~0;
+ d->blksize = FUSE_DEFAULT_BLKSIZE;
+
+ while ((p = strsep(&opt, ",")) != NULL) {
+ int token;
+ int value;
+ unsigned uv;
+ substring_t args[MAX_OPT_ARGS];
+ if (!*p)
+ continue;
+
+ token = match_token(p, tokens, args);
+ switch (token) {
+ case OPT_FD:
+ if (match_int(&args[0], &value))
+ return 0;
+ d->fd = value;
+ d->fd_present = 1;
+ break;
+
+ case OPT_ROOTMODE:
+ if (match_octal(&args[0], &value))
+ return 0;
+ if (!fuse_valid_type(value))
+ return 0;
+ d->rootmode = value;
+ d->rootmode_present = 1;
+ break;
+
+ case OPT_USER_ID:
+ if (fuse_match_uint(&args[0], &uv))
+ return 0;
+ d->user_id = make_kuid(current_user_ns(), uv);
+ if (!uid_valid(d->user_id))
+ return 0;
+ d->user_id_present = 1;
+ break;
+
+ case OPT_GROUP_ID:
+ if (fuse_match_uint(&args[0], &uv))
+ return 0;
+ d->group_id = make_kgid(current_user_ns(), uv);
+ if (!gid_valid(d->group_id))
+ return 0;
+ d->group_id_present = 1;
+ break;
+
+ case OPT_DEFAULT_PERMISSIONS:
+ d->flags |= FUSE_DEFAULT_PERMISSIONS;
+ break;
+
+ case OPT_ALLOW_OTHER:
+ d->flags |= FUSE_ALLOW_OTHER;
+ break;
+
+ case OPT_MAX_READ:
+ if (match_int(&args[0], &value))
+ return 0;
+ d->max_read = value;
+ break;
+
+ case OPT_BLKSIZE:
+ if (!is_bdev || match_int(&args[0], &value))
+ return 0;
+ d->blksize = value;
+ break;
+
+ default:
+ return 0;
+ }
+ }
+
+ if (!d->fd_present || !d->rootmode_present ||
+ !d->user_id_present || !d->group_id_present)
+ return 0;
+
+ return 1;
+}
+
+static int fuse_show_options(struct seq_file *m, struct dentry *root)
+{
+ struct super_block *sb = root->d_sb;
+ struct fuse_conn *fc = get_fuse_conn_super(sb);
+
+ seq_printf(m, ",user_id=%u", from_kuid_munged(&init_user_ns, fc->user_id));
+ seq_printf(m, ",group_id=%u", from_kgid_munged(&init_user_ns, fc->group_id));
+ if (fc->flags & FUSE_DEFAULT_PERMISSIONS)
+ seq_puts(m, ",default_permissions");
+ if (fc->flags & FUSE_ALLOW_OTHER)
+ seq_puts(m, ",allow_other");
+ if (fc->max_read != ~0)
+ seq_printf(m, ",max_read=%u", fc->max_read);
+ if (sb->s_bdev && sb->s_blocksize != FUSE_DEFAULT_BLKSIZE)
+ seq_printf(m, ",blksize=%lu", sb->s_blocksize);
+ return 0;
+}
+
+void fuse_conn_init(struct fuse_conn *fc)
+{
+ memset(fc, 0, sizeof(*fc));
+ spin_lock_init(&fc->lock);
+ init_rwsem(&fc->killsb);
+ atomic_set(&fc->count, 1);
+ init_waitqueue_head(&fc->waitq);
+ init_waitqueue_head(&fc->blocked_waitq);
+ init_waitqueue_head(&fc->reserved_req_waitq);
+ INIT_LIST_HEAD(&fc->pending);
+ INIT_LIST_HEAD(&fc->processing);
+ INIT_LIST_HEAD(&fc->io);
+ INIT_LIST_HEAD(&fc->interrupts);
+ INIT_LIST_HEAD(&fc->bg_queue);
+ INIT_LIST_HEAD(&fc->entry);
+ fc->forget_list_tail = &fc->forget_list_head;
+ atomic_set(&fc->num_waiting, 0);
+ fc->max_background = FUSE_DEFAULT_MAX_BACKGROUND;
+ fc->congestion_threshold = FUSE_DEFAULT_CONGESTION_THRESHOLD;
+ fc->khctr = 0;
+ fc->polled_files = RB_ROOT;
+ fc->reqctr = 0;
+ fc->blocked = 0;
+ fc->initialized = 0;
+ fc->attr_version = 1;
+ get_random_bytes(&fc->scramble_key, sizeof(fc->scramble_key));
+}
+EXPORT_SYMBOL_GPL(fuse_conn_init);
+
+void fuse_conn_put(struct fuse_conn *fc)
+{
+ if (atomic_dec_and_test(&fc->count)) {
+ if (fc->destroy_req)
+ fuse_request_free(fc->destroy_req);
+ fc->release(fc);
+ }
+}
+EXPORT_SYMBOL_GPL(fuse_conn_put);
+
+struct fuse_conn *fuse_conn_get(struct fuse_conn *fc)
+{
+ atomic_inc(&fc->count);
+ return fc;
+}
+EXPORT_SYMBOL_GPL(fuse_conn_get);
+
+static struct inode *fuse_get_root_inode(struct super_block *sb, unsigned mode)
+{
+ struct fuse_attr attr;
+ memset(&attr, 0, sizeof(attr));
+
+ attr.mode = mode;
+ attr.ino = FUSE_ROOT_ID;
+ attr.nlink = 1;
+ return fuse_iget(sb, 1, 0, &attr, 0, 0);
+}
+
+struct fuse_inode_handle {
+ u64 nodeid;
+ u32 generation;
+};
+
+static struct dentry *fuse_get_dentry(struct super_block *sb,
+ struct fuse_inode_handle *handle)
+{
+ struct fuse_conn *fc = get_fuse_conn_super(sb);
+ struct inode *inode;
+ struct dentry *entry;
+ int err = -ESTALE;
+
+ if (handle->nodeid == 0)
+ goto out_err;
+
+ inode = ilookup5(sb, handle->nodeid, fuse_inode_eq, &handle->nodeid);
+ if (!inode) {
+ struct fuse_entry_out outarg;
+ struct qstr name;
+
+ if (!fc->export_support)
+ goto out_err;
+
+ name.len = 1;
+ name.name = ".";
+ err = fuse_lookup_name(sb, handle->nodeid, &name, &outarg,
+ &inode);
+ if (err && err != -ENOENT)
+ goto out_err;
+ if (err || !inode) {
+ err = -ESTALE;
+ goto out_err;
+ }
+ err = -EIO;
+ if (get_node_id(inode) != handle->nodeid)
+ goto out_iput;
+ }
+ err = -ESTALE;
+ if (inode->i_generation != handle->generation)
+ goto out_iput;
+
+ entry = d_obtain_alias(inode);
+ if (!IS_ERR(entry) && get_node_id(inode) != FUSE_ROOT_ID)
+ fuse_invalidate_entry_cache(entry);
+
+ return entry;
+
+ out_iput:
+ iput(inode);
+ out_err:
+ return ERR_PTR(err);
+}
+
+static int fuse_encode_fh(struct inode *inode, u32 *fh, int *max_len,
+ struct inode *parent)
+{
+ int len = parent ? 6 : 3;
+ u64 nodeid;
+ u32 generation;
+
+ if (*max_len < len) {
+ *max_len = len;
+ return FILEID_INVALID;
+ }
+
+ nodeid = get_fuse_inode(inode)->nodeid;
+ generation = inode->i_generation;
+
+ fh[0] = (u32)(nodeid >> 32);
+ fh[1] = (u32)(nodeid & 0xffffffff);
+ fh[2] = generation;
+
+ if (parent) {
+ nodeid = get_fuse_inode(parent)->nodeid;
+ generation = parent->i_generation;
+
+ fh[3] = (u32)(nodeid >> 32);
+ fh[4] = (u32)(nodeid & 0xffffffff);
+ fh[5] = generation;
+ }
+
+ *max_len = len;
+ return parent ? 0x82 : 0x81;
+}
+
+static struct dentry *fuse_fh_to_dentry(struct super_block *sb,
+ struct fid *fid, int fh_len, int fh_type)
+{
+ struct fuse_inode_handle handle;
+
+ if ((fh_type != 0x81 && fh_type != 0x82) || fh_len < 3)
+ return NULL;
+
+ handle.nodeid = (u64) fid->raw[0] << 32;
+ handle.nodeid |= (u64) fid->raw[1];
+ handle.generation = fid->raw[2];
+ return fuse_get_dentry(sb, &handle);
+}
+
+static struct dentry *fuse_fh_to_parent(struct super_block *sb,
+ struct fid *fid, int fh_len, int fh_type)
+{
+ struct fuse_inode_handle parent;
+
+ if (fh_type != 0x82 || fh_len < 6)
+ return NULL;
+
+ parent.nodeid = (u64) fid->raw[3] << 32;
+ parent.nodeid |= (u64) fid->raw[4];
+ parent.generation = fid->raw[5];
+ return fuse_get_dentry(sb, &parent);
+}
+
+static struct dentry *fuse_get_parent(struct dentry *child)
+{
+ struct inode *child_inode = d_inode(child);
+ struct fuse_conn *fc = get_fuse_conn(child_inode);
+ struct inode *inode;
+ struct dentry *parent;
+ struct fuse_entry_out outarg;
+ struct qstr name;
+ int err;
+
+ if (!fc->export_support)
+ return ERR_PTR(-ESTALE);
+
+ name.len = 2;
+ name.name = "..";
+ err = fuse_lookup_name(child_inode->i_sb, get_node_id(child_inode),
+ &name, &outarg, &inode);
+ if (err) {
+ if (err == -ENOENT)
+ return ERR_PTR(-ESTALE);
+ return ERR_PTR(err);
+ }
+
+ parent = d_obtain_alias(inode);
+ if (!IS_ERR(parent) && get_node_id(inode) != FUSE_ROOT_ID)
+ fuse_invalidate_entry_cache(parent);
+
+ return parent;
+}
+
+static const struct export_operations fuse_export_operations = {
+ .fh_to_dentry = fuse_fh_to_dentry,
+ .fh_to_parent = fuse_fh_to_parent,
+ .encode_fh = fuse_encode_fh,
+ .get_parent = fuse_get_parent,
+};
+
+static const struct super_operations fuse_super_operations = {
+ .alloc_inode = fuse_alloc_inode,
+ .destroy_inode = fuse_destroy_inode,
+ .evict_inode = fuse_evict_inode,
+ .write_inode = fuse_write_inode,
+ .drop_inode = generic_delete_inode,
+ .remount_fs = fuse_remount_fs,
+ .put_super = fuse_put_super,
+ .umount_begin = fuse_umount_begin,
+ .statfs = fuse_statfs,
+ .show_options = fuse_show_options,
+};
+
+static void sanitize_global_limit(unsigned *limit)
+{
+ if (*limit == 0)
+ *limit = ((totalram_pages << PAGE_SHIFT) >> 13) /
+ sizeof(struct fuse_req);
+
+ if (*limit >= 1 << 16)
+ *limit = (1 << 16) - 1;
+}
+
+static int set_global_limit(const char *val, struct kernel_param *kp)
+{
+ int rv;
+
+ rv = param_set_uint(val, kp);
+ if (rv)
+ return rv;
+
+ sanitize_global_limit((unsigned *)kp->arg);
+
+ return 0;
+}
+
+static void process_init_limits(struct fuse_conn *fc, struct fuse_init_out *arg)
+{
+ int cap_sys_admin = capable(CAP_SYS_ADMIN);
+
+ if (arg->minor < 13)
+ return;
+
+ sanitize_global_limit(&max_user_bgreq);
+ sanitize_global_limit(&max_user_congthresh);
+
+ if (arg->max_background) {
+ fc->max_background = arg->max_background;
+
+ if (!cap_sys_admin && fc->max_background > max_user_bgreq)
+ fc->max_background = max_user_bgreq;
+ }
+ if (arg->congestion_threshold) {
+ fc->congestion_threshold = arg->congestion_threshold;
+
+ if (!cap_sys_admin &&
+ fc->congestion_threshold > max_user_congthresh)
+ fc->congestion_threshold = max_user_congthresh;
+ }
+}
+
+static void process_init_reply(struct fuse_conn *fc, struct fuse_req *req)
+{
+ struct fuse_init_out *arg = &req->misc.init_out;
+
+ if (req->out.h.error || arg->major != FUSE_KERNEL_VERSION)
+ fc->conn_error = 1;
+ else {
+ unsigned long ra_pages;
+
+ process_init_limits(fc, arg);
+
+ if (arg->minor >= 6) {
+ ra_pages = arg->max_readahead / PAGE_CACHE_SIZE;
+ if (arg->flags & FUSE_ASYNC_READ)
+ fc->async_read = 1;
+ if (!(arg->flags & FUSE_POSIX_LOCKS))
+ fc->no_lock = 1;
+ if (arg->minor >= 17) {
+ if (!(arg->flags & FUSE_FLOCK_LOCKS))
+ fc->no_flock = 1;
+ } else {
+ if (!(arg->flags & FUSE_POSIX_LOCKS))
+ fc->no_flock = 1;
+ }
+ if (arg->flags & FUSE_ATOMIC_O_TRUNC)
+ fc->atomic_o_trunc = 1;
+ if (arg->minor >= 9) {
+ /* LOOKUP has dependency on proto version */
+ if (arg->flags & FUSE_EXPORT_SUPPORT)
+ fc->export_support = 1;
+ }
+ if (arg->flags & FUSE_BIG_WRITES)
+ fc->big_writes = 1;
+ if (arg->flags & FUSE_DONT_MASK)
+ fc->dont_mask = 1;
+ if (arg->flags & FUSE_AUTO_INVAL_DATA)
+ fc->auto_inval_data = 1;
+ if (arg->flags & FUSE_DO_READDIRPLUS) {
+ fc->do_readdirplus = 1;
+ if (arg->flags & FUSE_READDIRPLUS_AUTO)
+ fc->readdirplus_auto = 1;
+ }
+ if (arg->flags & FUSE_ASYNC_DIO)
+ fc->async_dio = 1;
+ if (arg->flags & FUSE_WRITEBACK_CACHE)
+ fc->writeback_cache = 1;
+ if (arg->time_gran && arg->time_gran <= 1000000000)
+ fc->sb->s_time_gran = arg->time_gran;
+ } else {
+ ra_pages = fc->max_read / PAGE_CACHE_SIZE;
+ fc->no_lock = 1;
+ fc->no_flock = 1;
+ }
+
+ fc->bdi.ra_pages = min(fc->bdi.ra_pages, ra_pages);
+ fc->minor = arg->minor;
+ fc->max_write = arg->minor < 5 ? 4096 : arg->max_write;
+ fc->max_write = max_t(unsigned, 4096, fc->max_write);
+ fc->conn_init = 1;
+ }
+ fuse_set_initialized(fc);
+ wake_up_all(&fc->blocked_waitq);
+}
+
+static void fuse_send_init(struct fuse_conn *fc, struct fuse_req *req)
+{
+ struct fuse_init_in *arg = &req->misc.init_in;
+
+ arg->major = FUSE_KERNEL_VERSION;
+ arg->minor = FUSE_KERNEL_MINOR_VERSION;
+ arg->max_readahead = fc->bdi.ra_pages * PAGE_CACHE_SIZE;
+ arg->flags |= FUSE_ASYNC_READ | FUSE_POSIX_LOCKS | FUSE_ATOMIC_O_TRUNC |
+ FUSE_EXPORT_SUPPORT | FUSE_BIG_WRITES | FUSE_DONT_MASK |
+ FUSE_SPLICE_WRITE | FUSE_SPLICE_MOVE | FUSE_SPLICE_READ |
+ FUSE_FLOCK_LOCKS | FUSE_IOCTL_DIR | FUSE_AUTO_INVAL_DATA |
+ FUSE_DO_READDIRPLUS | FUSE_READDIRPLUS_AUTO | FUSE_ASYNC_DIO |
+ FUSE_WRITEBACK_CACHE | FUSE_NO_OPEN_SUPPORT;
+ req->in.h.opcode = FUSE_INIT;
+ req->in.numargs = 1;
+ req->in.args[0].size = sizeof(*arg);
+ req->in.args[0].value = arg;
+ req->out.numargs = 1;
+ /* Variable length argument used for backward compatibility
+ with interface version < 7.5. Rest of init_out is zeroed
+ by do_get_request(), so a short reply is not a problem */
+ req->out.argvar = 1;
+ req->out.args[0].size = sizeof(struct fuse_init_out);
+ req->out.args[0].value = &req->misc.init_out;
+ req->end = process_init_reply;
+ fuse_request_send_background(fc, req);
+}
+
+static void fuse_free_conn(struct fuse_conn *fc)
+{
+ kfree_rcu(fc, rcu);
+}
+
+static int fuse_bdi_init(struct fuse_conn *fc, struct super_block *sb)
+{
+ int err;
+
+ fc->bdi.name = "fuse";
+ fc->bdi.ra_pages = (VM_MAX_READAHEAD * 1024) / PAGE_CACHE_SIZE;
+ /* fuse does it's own writeback accounting */
+ fc->bdi.capabilities = BDI_CAP_NO_ACCT_WB | BDI_CAP_STRICTLIMIT;
+
+ err = bdi_init(&fc->bdi);
+ if (err)
+ return err;
+
+ fc->bdi_initialized = 1;
+
+ if (sb->s_bdev) {
+ err = bdi_register(&fc->bdi, NULL, "%u:%u-fuseblk",
+ MAJOR(fc->dev), MINOR(fc->dev));
+ } else {
+ err = bdi_register_dev(&fc->bdi, fc->dev);
+ }
+
+ if (err)
+ return err;
+
+ /*
+ * For a single fuse filesystem use max 1% of dirty +
+ * writeback threshold.
+ *
+ * This gives about 1M of write buffer for memory maps on a
+ * machine with 1G and 10% dirty_ratio, which should be more
+ * than enough.
+ *
+ * Privileged users can raise it by writing to
+ *
+ * /sys/class/bdi/<bdi>/max_ratio
+ */
+ bdi_set_max_ratio(&fc->bdi, 1);
+
+ return 0;
+}
+
+static int fuse_fill_super(struct super_block *sb, void *data, int silent)
+{
+ struct fuse_conn *fc;
+ struct inode *root;
+ struct fuse_mount_data d;
+ struct file *file;
+ struct dentry *root_dentry;
+ struct fuse_req *init_req;
+ int err;
+ int is_bdev = sb->s_bdev != NULL;
+
+ err = -EINVAL;
+ if (sb->s_flags & MS_MANDLOCK)
+ goto err;
+
+ sb->s_flags &= ~(MS_NOSEC | MS_I_VERSION);
+
+ if (!parse_fuse_opt(data, &d, is_bdev))
+ goto err;
+
+ if (is_bdev) {
+#ifdef CONFIG_BLOCK
+ err = -EINVAL;
+ if (!sb_set_blocksize(sb, d.blksize))
+ goto err;
+#endif
+ } else {
+ sb->s_blocksize = PAGE_CACHE_SIZE;
+ sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
+ }
+ sb->s_magic = FUSE_SUPER_MAGIC;
+ sb->s_op = &fuse_super_operations;
+ sb->s_maxbytes = MAX_LFS_FILESIZE;
+ sb->s_time_gran = 1;
+ sb->s_export_op = &fuse_export_operations;
+
+ file = fget(d.fd);
+ err = -EINVAL;
+ if (!file)
+ goto err;
+
+ if ((file->f_op != &fuse_dev_operations) ||
+ (file->f_cred->user_ns != &init_user_ns))
+ goto err_fput;
+
+ fc = kmalloc(sizeof(*fc), GFP_KERNEL);
+ err = -ENOMEM;
+ if (!fc)
+ goto err_fput;
+
+ fuse_conn_init(fc);
+
+ fc->dev = sb->s_dev;
+ fc->sb = sb;
+ err = fuse_bdi_init(fc, sb);
+ if (err)
+ goto err_put_conn;
+
+ sb->s_bdi = &fc->bdi;
+
+ /* Handle umasking inside the fuse code */
+ if (sb->s_flags & MS_POSIXACL)
+ fc->dont_mask = 1;
+ sb->s_flags |= MS_POSIXACL;
+
+ fc->release = fuse_free_conn;
+ fc->flags = d.flags;
+ fc->user_id = d.user_id;
+ fc->group_id = d.group_id;
+ fc->max_read = max_t(unsigned, 4096, d.max_read);
+
+ /* Used by get_root_inode() */
+ sb->s_fs_info = fc;
+
+ err = -ENOMEM;
+ root = fuse_get_root_inode(sb, d.rootmode);
+ root_dentry = d_make_root(root);
+ if (!root_dentry)
+ goto err_put_conn;
+ /* only now - we want root dentry with NULL ->d_op */
+ sb->s_d_op = &fuse_dentry_operations;
+
+ init_req = fuse_request_alloc(0);
+ if (!init_req)
+ goto err_put_root;
+ init_req->background = 1;
+
+ if (is_bdev) {
+ fc->destroy_req = fuse_request_alloc(0);
+ if (!fc->destroy_req)
+ goto err_free_init_req;
+ }
+
+ mutex_lock(&fuse_mutex);
+ err = -EINVAL;
+ if (file->private_data)
+ goto err_unlock;
+
+ err = fuse_ctl_add_conn(fc);
+ if (err)
+ goto err_unlock;
+
+ list_add_tail(&fc->entry, &fuse_conn_list);
+ sb->s_root = root_dentry;
+ fc->connected = 1;
+ file->private_data = fuse_conn_get(fc);
+ mutex_unlock(&fuse_mutex);
+ /*
+ * atomic_dec_and_test() in fput() provides the necessary
+ * memory barrier for file->private_data to be visible on all
+ * CPUs after this
+ */
+ fput(file);
+
+ fuse_send_init(fc, init_req);
+
+ return 0;
+
+ err_unlock:
+ mutex_unlock(&fuse_mutex);
+ err_free_init_req:
+ fuse_request_free(init_req);
+ err_put_root:
+ dput(root_dentry);
+ err_put_conn:
+ fuse_bdi_destroy(fc);
+ fuse_conn_put(fc);
+ err_fput:
+ fput(file);
+ err:
+ return err;
+}
+
+static struct dentry *fuse_mount(struct file_system_type *fs_type,
+ int flags, const char *dev_name,
+ void *raw_data)
+{
+ return mount_nodev(fs_type, flags, raw_data, fuse_fill_super);
+}
+
+static void fuse_kill_sb_anon(struct super_block *sb)
+{
+ struct fuse_conn *fc = get_fuse_conn_super(sb);
+
+ if (fc) {
+ down_write(&fc->killsb);
+ fc->sb = NULL;
+ up_write(&fc->killsb);
+ }
+
+ kill_anon_super(sb);
+}
+
+static struct file_system_type fuse_fs_type = {
+ .owner = THIS_MODULE,
+ .name = "fuse",
+ .fs_flags = FS_HAS_SUBTYPE,
+ .mount = fuse_mount,
+ .kill_sb = fuse_kill_sb_anon,
+};
+MODULE_ALIAS_FS("fuse");
+
+#ifdef CONFIG_BLOCK
+static struct dentry *fuse_mount_blk(struct file_system_type *fs_type,
+ int flags, const char *dev_name,
+ void *raw_data)
+{
+ return mount_bdev(fs_type, flags, dev_name, raw_data, fuse_fill_super);
+}
+
+static void fuse_kill_sb_blk(struct super_block *sb)
+{
+ struct fuse_conn *fc = get_fuse_conn_super(sb);
+
+ if (fc) {
+ down_write(&fc->killsb);
+ fc->sb = NULL;
+ up_write(&fc->killsb);
+ }
+
+ kill_block_super(sb);
+}
+
+static struct file_system_type fuseblk_fs_type = {
+ .owner = THIS_MODULE,
+ .name = "fuseblk",
+ .mount = fuse_mount_blk,
+ .kill_sb = fuse_kill_sb_blk,
+ .fs_flags = FS_REQUIRES_DEV | FS_HAS_SUBTYPE,
+};
+MODULE_ALIAS_FS("fuseblk");
+
+static inline int register_fuseblk(void)
+{
+ return register_filesystem(&fuseblk_fs_type);
+}
+
+static inline void unregister_fuseblk(void)
+{
+ unregister_filesystem(&fuseblk_fs_type);
+}
+#else
+static inline int register_fuseblk(void)
+{
+ return 0;
+}
+
+static inline void unregister_fuseblk(void)
+{
+}
+#endif
+
+static void fuse_inode_init_once(void *foo)
+{
+ struct inode *inode = foo;
+
+ inode_init_once(inode);
+}
+
+static int __init fuse_fs_init(void)
+{
+ int err;
+
+ fuse_inode_cachep = kmem_cache_create("fuse_inode",
+ sizeof(struct fuse_inode),
+ 0, SLAB_HWCACHE_ALIGN,
+ fuse_inode_init_once);
+ err = -ENOMEM;
+ if (!fuse_inode_cachep)
+ goto out;
+
+ err = register_fuseblk();
+ if (err)
+ goto out2;
+
+ err = register_filesystem(&fuse_fs_type);
+ if (err)
+ goto out3;
+
+ return 0;
+
+ out3:
+ unregister_fuseblk();
+ out2:
+ kmem_cache_destroy(fuse_inode_cachep);
+ out:
+ return err;
+}
+
+static void fuse_fs_cleanup(void)
+{
+ unregister_filesystem(&fuse_fs_type);
+ unregister_fuseblk();
+
+ /*
+ * Make sure all delayed rcu free inodes are flushed before we
+ * destroy cache.
+ */
+ rcu_barrier();
+ kmem_cache_destroy(fuse_inode_cachep);
+}
+
+static struct kobject *fuse_kobj;
+
+static int fuse_sysfs_init(void)
+{
+ int err;
+
+ fuse_kobj = kobject_create_and_add("fuse", fs_kobj);
+ if (!fuse_kobj) {
+ err = -ENOMEM;
+ goto out_err;
+ }
+
+ err = sysfs_create_mount_point(fuse_kobj, "connections");
+ if (err)
+ goto out_fuse_unregister;
+
+ return 0;
+
+ out_fuse_unregister:
+ kobject_put(fuse_kobj);
+ out_err:
+ return err;
+}
+
+static void fuse_sysfs_cleanup(void)
+{
+ sysfs_remove_mount_point(fuse_kobj, "connections");
+ kobject_put(fuse_kobj);
+}
+
+static int __init fuse_init(void)
+{
+ int res;
+
+ printk(KERN_INFO "fuse init (API version %i.%i)\n",
+ FUSE_KERNEL_VERSION, FUSE_KERNEL_MINOR_VERSION);
+
+ INIT_LIST_HEAD(&fuse_conn_list);
+ res = fuse_fs_init();
+ if (res)
+ goto err;
+
+ res = fuse_dev_init();
+ if (res)
+ goto err_fs_cleanup;
+
+ res = fuse_sysfs_init();
+ if (res)
+ goto err_dev_cleanup;
+
+ res = fuse_ctl_init();
+ if (res)
+ goto err_sysfs_cleanup;
+
+ sanitize_global_limit(&max_user_bgreq);
+ sanitize_global_limit(&max_user_congthresh);
+
+ return 0;
+
+ err_sysfs_cleanup:
+ fuse_sysfs_cleanup();
+ err_dev_cleanup:
+ fuse_dev_cleanup();
+ err_fs_cleanup:
+ fuse_fs_cleanup();
+ err:
+ return res;
+}
+
+static void __exit fuse_exit(void)
+{
+ printk(KERN_DEBUG "fuse exit\n");
+
+ fuse_ctl_cleanup();
+ fuse_sysfs_cleanup();
+ fuse_fs_cleanup();
+ fuse_dev_cleanup();
+}
+
+module_init(fuse_init);
+module_exit(fuse_exit);
Code Review / kvmfornfv.git / blobdiff