From e5e5558e923f35839108a12718494ecb73fb782f Mon Sep 17 00:00:00 2001 From: Miklos Szeredi Date: Fri, 9 Sep 2005 13:10:28 -0700 Subject: [PATCH] [PATCH] FUSE - read-only operations This patch adds the read-only filesystem operations of FUSE. This contains the following files: o dir.c - directory, symlink and file-inode operations The following operations are added: o lookup o getattr o readlink o follow_link o directory open o readdir o directory release o permission o dentry revalidate o statfs Signed-off-by: Miklos Szeredi Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- fs/fuse/Makefile | 2 +- fs/fuse/dev.c | 9 + fs/fuse/dir.c | 413 +++++++++++++++++++++++++++++++++++++++++++ fs/fuse/fuse_i.h | 51 ++++++ fs/fuse/inode.c | 81 +++++++++ include/linux/fuse.h | 60 +++++++ 6 files changed, 615 insertions(+), 1 deletion(-) create mode 100644 fs/fuse/dir.c diff --git a/fs/fuse/Makefile b/fs/fuse/Makefile index 21021c356481..c34e268a0ed3 100644 --- a/fs/fuse/Makefile +++ b/fs/fuse/Makefile @@ -4,4 +4,4 @@ obj-$(CONFIG_FUSE_FS) += fuse.o -fuse-objs := dev.o inode.o +fuse-objs := dev.o dir.o inode.o diff --git a/fs/fuse/dev.c b/fs/fuse/dev.c index 9aaf10a6588f..e8f3170946f1 100644 --- a/fs/fuse/dev.c +++ b/fs/fuse/dev.c @@ -691,6 +691,13 @@ static struct fuse_req *request_find(struct fuse_conn *fc, u64 unique) return NULL; } +/* fget() needs to be done in this context */ +static void process_getdir(struct fuse_req *req) +{ + struct fuse_getdir_out_i *arg = req->out.args[0].value; + arg->file = fget(arg->fd); +} + static int copy_out_args(struct fuse_copy_state *cs, struct fuse_out *out, unsigned nbytes) { @@ -770,6 +777,8 @@ static ssize_t fuse_dev_writev(struct file *file, const struct iovec *iov, if (!err) { if (req->interrupted) err = -ENOENT; + else if (req->in.h.opcode == FUSE_GETDIR && !oh.error) + process_getdir(req); } else if (!req->interrupted) req->out.h.error = -EIO; request_end(fc, req); diff --git a/fs/fuse/dir.c b/fs/fuse/dir.c new file mode 100644 index 000000000000..a89730e70c58 --- /dev/null +++ b/fs/fuse/dir.c @@ -0,0 +1,413 @@ +/* + FUSE: Filesystem in Userspace + Copyright (C) 2001-2005 Miklos Szeredi + + This program can be distributed under the terms of the GNU GPL. + See the file COPYING. +*/ + +#include "fuse_i.h" + +#include +#include +#include +#include +#include + +static inline unsigned long time_to_jiffies(unsigned long sec, + unsigned long nsec) +{ + struct timespec ts = {sec, nsec}; + return jiffies + timespec_to_jiffies(&ts); +} + +static void fuse_lookup_init(struct fuse_req *req, struct inode *dir, + struct dentry *entry, + struct fuse_entry_out *outarg) +{ + req->in.h.opcode = FUSE_LOOKUP; + req->in.h.nodeid = get_node_id(dir); + req->inode = dir; + req->in.numargs = 1; + req->in.args[0].size = entry->d_name.len + 1; + req->in.args[0].value = entry->d_name.name; + req->out.numargs = 1; + req->out.args[0].size = sizeof(struct fuse_entry_out); + req->out.args[0].value = outarg; +} + +static int fuse_dentry_revalidate(struct dentry *entry, struct nameidata *nd) +{ + if (!entry->d_inode || is_bad_inode(entry->d_inode)) + return 0; + else if (time_after(jiffies, entry->d_time)) { + int err; + int version; + struct fuse_entry_out outarg; + struct inode *inode = entry->d_inode; + struct fuse_inode *fi = get_fuse_inode(inode); + struct fuse_conn *fc = get_fuse_conn(inode); + struct fuse_req *req = fuse_get_request_nonint(fc); + if (!req) + return 0; + + fuse_lookup_init(req, entry->d_parent->d_inode, entry, &outarg); + request_send_nonint(fc, req); + version = req->out.h.unique; + err = req->out.h.error; + fuse_put_request(fc, req); + if (err || outarg.nodeid != get_node_id(inode) || + (outarg.attr.mode ^ inode->i_mode) & S_IFMT) + return 0; + + fuse_change_attributes(inode, &outarg.attr); + inode->i_version = version; + entry->d_time = time_to_jiffies(outarg.entry_valid, + outarg.entry_valid_nsec); + fi->i_time = time_to_jiffies(outarg.attr_valid, + outarg.attr_valid_nsec); + } + return 1; +} + +static struct dentry_operations fuse_dentry_operations = { + .d_revalidate = fuse_dentry_revalidate, +}; + +static int fuse_lookup_iget(struct inode *dir, struct dentry *entry, + struct inode **inodep) +{ + int err; + int version; + struct fuse_entry_out outarg; + struct inode *inode = NULL; + struct fuse_conn *fc = get_fuse_conn(dir); + struct fuse_req *req; + + if (entry->d_name.len > FUSE_NAME_MAX) + return -ENAMETOOLONG; + + req = fuse_get_request(fc); + if (!req) + return -ERESTARTNOINTR; + + fuse_lookup_init(req, dir, entry, &outarg); + request_send(fc, req); + version = req->out.h.unique; + err = req->out.h.error; + if (!err) { + inode = fuse_iget(dir->i_sb, outarg.nodeid, outarg.generation, + &outarg.attr, version); + if (!inode) { + fuse_send_forget(fc, req, outarg.nodeid, version); + return -ENOMEM; + } + } + fuse_put_request(fc, req); + if (err && err != -ENOENT) + return err; + + if (inode) { + struct fuse_inode *fi = get_fuse_inode(inode); + entry->d_time = time_to_jiffies(outarg.entry_valid, + outarg.entry_valid_nsec); + fi->i_time = time_to_jiffies(outarg.attr_valid, + outarg.attr_valid_nsec); + } + + entry->d_op = &fuse_dentry_operations; + *inodep = inode; + return 0; +} + +int fuse_do_getattr(struct inode *inode) +{ + int err; + struct fuse_attr_out arg; + struct fuse_conn *fc = get_fuse_conn(inode); + struct fuse_req *req = fuse_get_request(fc); + if (!req) + return -ERESTARTNOINTR; + + req->in.h.opcode = FUSE_GETATTR; + req->in.h.nodeid = get_node_id(inode); + req->inode = inode; + req->out.numargs = 1; + req->out.args[0].size = sizeof(arg); + req->out.args[0].value = &arg; + request_send(fc, req); + err = req->out.h.error; + fuse_put_request(fc, req); + if (!err) { + if ((inode->i_mode ^ arg.attr.mode) & S_IFMT) { + make_bad_inode(inode); + err = -EIO; + } else { + struct fuse_inode *fi = get_fuse_inode(inode); + fuse_change_attributes(inode, &arg.attr); + fi->i_time = time_to_jiffies(arg.attr_valid, + arg.attr_valid_nsec); + } + } + return err; +} + +static int fuse_revalidate(struct dentry *entry) +{ + struct inode *inode = entry->d_inode; + struct fuse_inode *fi = get_fuse_inode(inode); + struct fuse_conn *fc = get_fuse_conn(inode); + + if (get_node_id(inode) == FUSE_ROOT_ID) { + if (current->fsuid != fc->user_id) + return -EACCES; + } else if (time_before_eq(jiffies, fi->i_time)) + return 0; + + return fuse_do_getattr(inode); +} + +static int fuse_permission(struct inode *inode, int mask, struct nameidata *nd) +{ + struct fuse_conn *fc = get_fuse_conn(inode); + + if (current->fsuid != fc->user_id) + return -EACCES; + else { + int mode = inode->i_mode; + if ((mask & MAY_WRITE) && IS_RDONLY(inode) && + (S_ISREG(mode) || S_ISDIR(mode) || S_ISLNK(mode))) + return -EROFS; + if ((mask & MAY_EXEC) && !S_ISDIR(mode) && !(mode & S_IXUGO)) + return -EACCES; + return 0; + } +} + +static int parse_dirfile(char *buf, size_t nbytes, struct file *file, + void *dstbuf, filldir_t filldir) +{ + while (nbytes >= FUSE_NAME_OFFSET) { + struct fuse_dirent *dirent = (struct fuse_dirent *) buf; + size_t reclen = FUSE_DIRENT_SIZE(dirent); + int over; + if (!dirent->namelen || dirent->namelen > FUSE_NAME_MAX) + return -EIO; + if (reclen > nbytes) + break; + + over = filldir(dstbuf, dirent->name, dirent->namelen, + file->f_pos, dirent->ino, dirent->type); + if (over) + break; + + buf += reclen; + nbytes -= reclen; + file->f_pos = dirent->off; + } + + return 0; +} + +static int fuse_checkdir(struct file *cfile, struct file *file) +{ + struct inode *inode; + if (!cfile) + return -EIO; + inode = cfile->f_dentry->d_inode; + if (!S_ISREG(inode->i_mode)) { + fput(cfile); + return -EIO; + } + + file->private_data = cfile; + return 0; +} + +static int fuse_getdir(struct file *file) +{ + struct inode *inode = file->f_dentry->d_inode; + struct fuse_conn *fc = get_fuse_conn(inode); + struct fuse_req *req = fuse_get_request(fc); + struct fuse_getdir_out_i outarg; + int err; + + if (!req) + return -ERESTARTNOINTR; + + req->in.h.opcode = FUSE_GETDIR; + req->in.h.nodeid = get_node_id(inode); + req->inode = inode; + req->out.numargs = 1; + req->out.args[0].size = sizeof(struct fuse_getdir_out); + req->out.args[0].value = &outarg; + request_send(fc, req); + err = req->out.h.error; + fuse_put_request(fc, req); + if (!err) + err = fuse_checkdir(outarg.file, file); + return err; +} + +static int fuse_readdir(struct file *file, void *dstbuf, filldir_t filldir) +{ + struct file *cfile = file->private_data; + char *buf; + int ret; + + if (!cfile) { + ret = fuse_getdir(file); + if (ret) + return ret; + + cfile = file->private_data; + } + + buf = (char *) __get_free_page(GFP_KERNEL); + if (!buf) + return -ENOMEM; + + ret = kernel_read(cfile, file->f_pos, buf, PAGE_SIZE); + if (ret > 0) + ret = parse_dirfile(buf, ret, file, dstbuf, filldir); + + free_page((unsigned long) buf); + return ret; +} + +static char *read_link(struct dentry *dentry) +{ + struct inode *inode = dentry->d_inode; + struct fuse_conn *fc = get_fuse_conn(inode); + struct fuse_req *req = fuse_get_request(fc); + char *link; + + if (!req) + return ERR_PTR(-ERESTARTNOINTR); + + link = (char *) __get_free_page(GFP_KERNEL); + if (!link) { + link = ERR_PTR(-ENOMEM); + goto out; + } + req->in.h.opcode = FUSE_READLINK; + req->in.h.nodeid = get_node_id(inode); + req->inode = inode; + req->out.argvar = 1; + req->out.numargs = 1; + req->out.args[0].size = PAGE_SIZE - 1; + req->out.args[0].value = link; + request_send(fc, req); + if (req->out.h.error) { + free_page((unsigned long) link); + link = ERR_PTR(req->out.h.error); + } else + link[req->out.args[0].size] = '\0'; + out: + fuse_put_request(fc, req); + return link; +} + +static void free_link(char *link) +{ + if (!IS_ERR(link)) + free_page((unsigned long) link); +} + +static void *fuse_follow_link(struct dentry *dentry, struct nameidata *nd) +{ + nd_set_link(nd, read_link(dentry)); + return NULL; +} + +static void fuse_put_link(struct dentry *dentry, struct nameidata *nd, void *c) +{ + free_link(nd_get_link(nd)); +} + +static int fuse_dir_open(struct inode *inode, struct file *file) +{ + file->private_data = NULL; + return 0; +} + +static int fuse_dir_release(struct inode *inode, struct file *file) +{ + struct file *cfile = file->private_data; + + if (cfile) + fput(cfile); + + return 0; +} + +static int fuse_getattr(struct vfsmount *mnt, struct dentry *entry, + struct kstat *stat) +{ + struct inode *inode = entry->d_inode; + int err = fuse_revalidate(entry); + if (!err) + generic_fillattr(inode, stat); + + return err; +} + +static struct dentry *fuse_lookup(struct inode *dir, struct dentry *entry, + struct nameidata *nd) +{ + struct inode *inode; + int err = fuse_lookup_iget(dir, entry, &inode); + if (err) + return ERR_PTR(err); + if (inode && S_ISDIR(inode->i_mode)) { + /* Don't allow creating an alias to a directory */ + struct dentry *alias = d_find_alias(inode); + if (alias && !(alias->d_flags & DCACHE_DISCONNECTED)) { + dput(alias); + iput(inode); + return ERR_PTR(-EIO); + } + } + return d_splice_alias(inode, entry); +} + +static struct inode_operations fuse_dir_inode_operations = { + .lookup = fuse_lookup, + .permission = fuse_permission, + .getattr = fuse_getattr, +}; + +static struct file_operations fuse_dir_operations = { + .read = generic_read_dir, + .readdir = fuse_readdir, + .open = fuse_dir_open, + .release = fuse_dir_release, +}; + +static struct inode_operations fuse_common_inode_operations = { + .permission = fuse_permission, + .getattr = fuse_getattr, +}; + +static struct inode_operations fuse_symlink_inode_operations = { + .follow_link = fuse_follow_link, + .put_link = fuse_put_link, + .readlink = generic_readlink, + .getattr = fuse_getattr, +}; + +void fuse_init_common(struct inode *inode) +{ + inode->i_op = &fuse_common_inode_operations; +} + +void fuse_init_dir(struct inode *inode) +{ + inode->i_op = &fuse_dir_inode_operations; + inode->i_fop = &fuse_dir_operations; +} + +void fuse_init_symlink(struct inode *inode) +{ + inode->i_op = &fuse_symlink_inode_operations; +} diff --git a/fs/fuse/fuse_i.h b/fs/fuse/fuse_i.h index 50ad6a0c39bf..8d91e1492f96 100644 --- a/fs/fuse/fuse_i.h +++ b/fs/fuse/fuse_i.h @@ -30,6 +30,9 @@ struct fuse_inode { * and kernel */ u64 nodeid; + /** The request used for sending the FORGET message */ + struct fuse_req *forget_req; + /** Time in jiffies until the file attributes are valid */ unsigned long i_time; }; @@ -129,6 +132,7 @@ struct fuse_req { /** Data for asynchronous requests */ union { + struct fuse_forget_in forget_in; struct fuse_init_in_out init_in_out; } misc; @@ -197,6 +201,11 @@ struct fuse_conn { struct backing_dev_info bdi; }; +struct fuse_getdir_out_i { + int fd; + void *file; /* Used by kernel only */ +}; + static inline struct fuse_conn **get_fuse_conn_super_p(struct super_block *sb) { return (struct fuse_conn **) &sb->s_fs_info; @@ -239,6 +248,38 @@ extern struct file_operations fuse_dev_operations; */ extern spinlock_t fuse_lock; +/** + * Get a filled in inode + */ +struct inode *fuse_iget(struct super_block *sb, unsigned long nodeid, + int generation, struct fuse_attr *attr, int version); + +/** + * Send FORGET command + */ +void fuse_send_forget(struct fuse_conn *fc, struct fuse_req *req, + unsigned long nodeid, int version); + +/** + * Initialise inode operations on regular files and special files + */ +void fuse_init_common(struct inode *inode); + +/** + * Initialise inode and file operations on a directory + */ +void fuse_init_dir(struct inode *inode); + +/** + * Initialise inode operations on a symlink + */ +void fuse_init_symlink(struct inode *inode); + +/** + * Change attributes of an inode + */ +void fuse_change_attributes(struct inode *inode, struct fuse_attr *attr); + /** * Check if the connection can be released, and if yes, then free the * connection structure @@ -306,6 +347,16 @@ void request_send_noreply(struct fuse_conn *fc, struct fuse_req *req); */ void request_send_background(struct fuse_conn *fc, struct fuse_req *req); +/** + * Get the attributes of a file + */ +int fuse_do_getattr(struct inode *inode); + +/** + * Invalidate inode attributes + */ +void fuse_invalidate_attr(struct inode *inode); + /** * Send the INIT message */ diff --git a/fs/fuse/inode.c b/fs/fuse/inode.c index 33fad334ba70..41498a1952a0 100644 --- a/fs/fuse/inode.c +++ b/fs/fuse/inode.c @@ -51,12 +51,20 @@ static struct inode *fuse_alloc_inode(struct super_block *sb) fi = get_fuse_inode(inode); fi->i_time = jiffies - 1; fi->nodeid = 0; + fi->forget_req = fuse_request_alloc(); + if (!fi->forget_req) { + kmem_cache_free(fuse_inode_cachep, inode); + return NULL; + } return inode; } static void fuse_destroy_inode(struct inode *inode) { + struct fuse_inode *fi = get_fuse_inode(inode); + if (fi->forget_req) + fuse_request_free(fi->forget_req); kmem_cache_free(fuse_inode_cachep, inode); } @@ -65,8 +73,27 @@ static void fuse_read_inode(struct inode *inode) /* No op */ } +void fuse_send_forget(struct fuse_conn *fc, struct fuse_req *req, + unsigned long nodeid, int version) +{ + struct fuse_forget_in *inarg = &req->misc.forget_in; + inarg->version = version; + req->in.h.opcode = FUSE_FORGET; + req->in.h.nodeid = nodeid; + req->in.numargs = 1; + req->in.args[0].size = sizeof(struct fuse_forget_in); + req->in.args[0].value = inarg; + request_send_noreply(fc, req); +} + static void fuse_clear_inode(struct inode *inode) { + struct fuse_conn *fc = get_fuse_conn(inode); + if (fc) { + struct fuse_inode *fi = get_fuse_inode(inode); + fuse_send_forget(fc, fi->forget_req, fi->nodeid, inode->i_version); + fi->forget_req = NULL; + } } void fuse_change_attributes(struct inode *inode, struct fuse_attr *attr) @@ -94,6 +121,22 @@ static void fuse_init_inode(struct inode *inode, struct fuse_attr *attr) { inode->i_mode = attr->mode & S_IFMT; i_size_write(inode, attr->size); + if (S_ISREG(inode->i_mode)) { + fuse_init_common(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 { + /* Don't let user create weird files */ + inode->i_mode = S_IFREG; + fuse_init_common(inode); + } } static int fuse_inode_eq(struct inode *inode, void *_nodeidp) @@ -158,6 +201,43 @@ static void fuse_put_super(struct super_block *sb) spin_unlock(&fuse_lock); } +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_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 super_block *sb, struct kstatfs *buf) +{ + struct fuse_conn *fc = get_fuse_conn_super(sb); + struct fuse_req *req; + struct fuse_statfs_out outarg; + int err; + + req = fuse_get_request(fc); + if (!req) + return -ERESTARTSYS; + + req->in.numargs = 0; + req->in.h.opcode = FUSE_STATFS; + req->out.numargs = 1; + req->out.args[0].size = sizeof(outarg); + req->out.args[0].value = &outarg; + request_send(fc, req); + err = req->out.h.error; + if (!err) + convert_fuse_statfs(buf, &outarg.st); + fuse_put_request(fc, req); + return err; +} + enum { OPT_FD, OPT_ROOTMODE, @@ -318,6 +398,7 @@ static struct super_operations fuse_super_operations = { .read_inode = fuse_read_inode, .clear_inode = fuse_clear_inode, .put_super = fuse_put_super, + .statfs = fuse_statfs, .show_options = fuse_show_options, }; diff --git a/include/linux/fuse.h b/include/linux/fuse.h index a1aebd7104c4..21b9ba16f8d5 100644 --- a/include/linux/fuse.h +++ b/include/linux/fuse.h @@ -42,13 +42,61 @@ struct fuse_attr { __u32 rdev; }; +struct fuse_kstatfs { + __u64 blocks; + __u64 bfree; + __u64 bavail; + __u64 files; + __u64 ffree; + __u32 bsize; + __u32 namelen; +}; + enum fuse_opcode { + FUSE_LOOKUP = 1, + FUSE_FORGET = 2, /* no reply */ + FUSE_GETATTR = 3, + FUSE_READLINK = 5, + FUSE_GETDIR = 7, + FUSE_STATFS = 17, FUSE_INIT = 26 }; /* Conservative buffer size for the client */ #define FUSE_MAX_IN 8192 +#define FUSE_NAME_MAX 1024 + +struct fuse_entry_out { + __u64 nodeid; /* Inode ID */ + __u64 generation; /* Inode generation: nodeid:gen must + be unique for the fs's lifetime */ + __u64 entry_valid; /* Cache timeout for the name */ + __u64 attr_valid; /* Cache timeout for the attributes */ + __u32 entry_valid_nsec; + __u32 attr_valid_nsec; + struct fuse_attr attr; +}; + +struct fuse_forget_in { + __u64 version; +}; + +struct fuse_attr_out { + __u64 attr_valid; /* Cache timeout for the attributes */ + __u32 attr_valid_nsec; + __u32 dummy; + struct fuse_attr attr; +}; + +struct fuse_getdir_out { + __u32 fd; +}; + +struct fuse_statfs_out { + struct fuse_kstatfs st; +}; + struct fuse_init_in_out { __u32 major; __u32 minor; @@ -70,3 +118,15 @@ struct fuse_out_header { __u64 unique; }; +struct fuse_dirent { + __u64 ino; + __u64 off; + __u32 namelen; + __u32 type; + char name[0]; +}; + +#define FUSE_NAME_OFFSET ((unsigned) ((struct fuse_dirent *) 0)->name) +#define FUSE_DIRENT_ALIGN(x) (((x) + sizeof(__u64) - 1) & ~(sizeof(__u64) - 1)) +#define FUSE_DIRENT_SIZE(d) \ + FUSE_DIRENT_ALIGN(FUSE_NAME_OFFSET + (d)->namelen) -- 2.30.2