diff options
Diffstat (limited to 'fs/hostfs/hostfs_kern.c')
-rw-r--r-- | fs/hostfs/hostfs_kern.c | 517 |
1 files changed, 229 insertions, 288 deletions
diff --git a/fs/hostfs/hostfs_kern.c b/fs/hostfs/hostfs_kern.c index 87ac189..dd1e555 100644 --- a/fs/hostfs/hostfs_kern.c +++ b/fs/hostfs/hostfs_kern.c @@ -14,12 +14,12 @@ #include <linux/slab.h> #include <linux/seq_file.h> #include <linux/mount.h> +#include <linux/namei.h> #include "hostfs.h" #include "init.h" #include "kern.h" struct hostfs_inode_info { - char *host_filename; int fd; fmode_t mode; struct inode vfs_inode; @@ -49,7 +49,7 @@ static int append = 0; static const struct inode_operations hostfs_iops; static const struct inode_operations hostfs_dir_iops; -static const struct address_space_operations hostfs_link_aops; +static const struct inode_operations hostfs_link_iops; #ifndef MODULE static int __init hostfs_args(char *options, int *add) @@ -90,71 +90,58 @@ __uml_setup("hostfs=", hostfs_args, ); #endif -static char *dentry_name(struct dentry *dentry, int extra) +static char *__dentry_name(struct dentry *dentry, char *name) { - struct dentry *parent; - char *root, *name; - int len; - - len = 0; - parent = dentry; - while (parent->d_parent != parent) { - len += parent->d_name.len + 1; - parent = parent->d_parent; - } + char *p = __dentry_path(dentry, name, PATH_MAX); + char *root; + size_t len; - root = HOSTFS_I(parent->d_inode)->host_filename; - len += strlen(root); - name = kmalloc(len + extra + 1, GFP_KERNEL); - if (name == NULL) - return NULL; + spin_unlock(&dcache_lock); - name[len] = '\0'; - parent = dentry; - while (parent->d_parent != parent) { - len -= parent->d_name.len + 1; - name[len] = '/'; - strncpy(&name[len + 1], parent->d_name.name, - parent->d_name.len); - parent = parent->d_parent; + root = dentry->d_sb->s_fs_info; + len = strlen(root); + if (IS_ERR(p)) { + __putname(name); + return NULL; + } + strncpy(name, root, PATH_MAX); + if (len > p - name) { + __putname(name); + return NULL; + } + if (p > name + len) { + char *s = name + len; + while ((*s++ = *p++) != '\0') + ; } - strncpy(name, root, strlen(root)); return name; } -static char *inode_name(struct inode *ino, int extra) +static char *dentry_name(struct dentry *dentry) { - struct dentry *dentry; + char *name = __getname(); + if (!name) + return NULL; - dentry = list_entry(ino->i_dentry.next, struct dentry, d_alias); - return dentry_name(dentry, extra); + spin_lock(&dcache_lock); + return __dentry_name(dentry, name); /* will unlock */ } -static int read_name(struct inode *ino, char *name) +static char *inode_name(struct inode *ino) { - /* - * The non-int inode fields are copied into ints by stat_file and - * then copied into the inode because passing the actual pointers - * in and having them treated as int * breaks on big-endian machines - */ - int err; - int i_mode, i_nlink, i_blksize; - unsigned long long i_size; - unsigned long long i_ino; - unsigned long long i_blocks; - - err = stat_file(name, &i_ino, &i_mode, &i_nlink, &ino->i_uid, - &ino->i_gid, &i_size, &ino->i_atime, &ino->i_mtime, - &ino->i_ctime, &i_blksize, &i_blocks, -1); - if (err) - return err; + struct dentry *dentry; + char *name = __getname(); + if (!name) + return NULL; - ino->i_ino = i_ino; - ino->i_mode = i_mode; - ino->i_nlink = i_nlink; - ino->i_size = i_size; - ino->i_blocks = i_blocks; - return 0; + spin_lock(&dcache_lock); + if (list_empty(&ino->i_dentry)) { + spin_unlock(&dcache_lock); + __putname(name); + return NULL; + } + dentry = list_first_entry(&ino->i_dentry, struct dentry, d_alias); + return __dentry_name(dentry, name); /* will unlock */ } static char *follow_link(char *link) @@ -205,53 +192,11 @@ static char *follow_link(char *link) return ERR_PTR(n); } -static int hostfs_read_inode(struct inode *ino) -{ - char *name; - int err = 0; - - /* - * Unfortunately, we are called from iget() when we don't have a dentry - * allocated yet. - */ - if (list_empty(&ino->i_dentry)) - goto out; - - err = -ENOMEM; - name = inode_name(ino, 0); - if (name == NULL) - goto out; - - if (file_type(name, NULL, NULL) == OS_TYPE_SYMLINK) { - name = follow_link(name); - if (IS_ERR(name)) { - err = PTR_ERR(name); - goto out; - } - } - - err = read_name(ino, name); - kfree(name); - out: - return err; -} - static struct inode *hostfs_iget(struct super_block *sb) { - struct inode *inode; - long ret; - - inode = iget_locked(sb, 0); + struct inode *inode = new_inode(sb); if (!inode) return ERR_PTR(-ENOMEM); - if (inode->i_state & I_NEW) { - ret = hostfs_read_inode(inode); - if (ret < 0) { - iget_failed(inode); - return ERR_PTR(ret); - } - unlock_new_inode(inode); - } return inode; } @@ -269,7 +214,7 @@ int hostfs_statfs(struct dentry *dentry, struct kstatfs *sf) long long f_files; long long f_ffree; - err = do_statfs(HOSTFS_I(dentry->d_sb->s_root->d_inode)->host_filename, + err = do_statfs(dentry->d_sb->s_fs_info, &sf->f_bsize, &f_blocks, &f_bfree, &f_bavail, &f_files, &f_ffree, &sf->f_fsid, sizeof(sf->f_fsid), &sf->f_namelen, sf->f_spare); @@ -288,47 +233,32 @@ static struct inode *hostfs_alloc_inode(struct super_block *sb) { struct hostfs_inode_info *hi; - hi = kmalloc(sizeof(*hi), GFP_KERNEL); + hi = kzalloc(sizeof(*hi), GFP_KERNEL); if (hi == NULL) return NULL; - - *hi = ((struct hostfs_inode_info) { .host_filename = NULL, - .fd = -1, - .mode = 0 }); + hi->fd = -1; inode_init_once(&hi->vfs_inode); return &hi->vfs_inode; } -static void hostfs_delete_inode(struct inode *inode) +static void hostfs_evict_inode(struct inode *inode) { truncate_inode_pages(&inode->i_data, 0); + end_writeback(inode); if (HOSTFS_I(inode)->fd != -1) { close_file(&HOSTFS_I(inode)->fd); HOSTFS_I(inode)->fd = -1; } - clear_inode(inode); } static void hostfs_destroy_inode(struct inode *inode) { - kfree(HOSTFS_I(inode)->host_filename); - - /* - * XXX: This should not happen, probably. The check is here for - * additional safety. - */ - if (HOSTFS_I(inode)->fd != -1) { - close_file(&HOSTFS_I(inode)->fd); - printk(KERN_DEBUG "Closing host fd in .destroy_inode\n"); - } - kfree(HOSTFS_I(inode)); } static int hostfs_show_options(struct seq_file *seq, struct vfsmount *vfs) { - struct inode *root = vfs->mnt_sb->s_root->d_inode; - const char *root_path = HOSTFS_I(root)->host_filename; + const char *root_path = vfs->mnt_sb->s_fs_info; size_t offset = strlen(root_ino) + 1; if (strlen(root_path) > offset) @@ -339,9 +269,8 @@ static int hostfs_show_options(struct seq_file *seq, struct vfsmount *vfs) static const struct super_operations hostfs_sbops = { .alloc_inode = hostfs_alloc_inode, - .drop_inode = generic_delete_inode, - .delete_inode = hostfs_delete_inode, .destroy_inode = hostfs_destroy_inode, + .evict_inode = hostfs_evict_inode, .statfs = hostfs_statfs, .show_options = hostfs_show_options, }; @@ -353,11 +282,11 @@ int hostfs_readdir(struct file *file, void *ent, filldir_t filldir) unsigned long long next, ino; int error, len; - name = dentry_name(file->f_path.dentry, 0); + name = dentry_name(file->f_path.dentry); if (name == NULL) return -ENOMEM; dir = open_dir(name, &error); - kfree(name); + __putname(name); if (dir == NULL) return -error; next = file->f_pos; @@ -373,40 +302,59 @@ int hostfs_readdir(struct file *file, void *ent, filldir_t filldir) int hostfs_file_open(struct inode *ino, struct file *file) { + static DEFINE_MUTEX(open_mutex); char *name; fmode_t mode = 0; + int err; int r = 0, w = 0, fd; mode = file->f_mode & (FMODE_READ | FMODE_WRITE); if ((mode & HOSTFS_I(ino)->mode) == mode) return 0; - /* - * The file may already have been opened, but with the wrong access, - * so this resets things and reopens the file with the new access. - */ - if (HOSTFS_I(ino)->fd != -1) { - close_file(&HOSTFS_I(ino)->fd); - HOSTFS_I(ino)->fd = -1; - } + mode |= HOSTFS_I(ino)->mode; - HOSTFS_I(ino)->mode |= mode; - if (HOSTFS_I(ino)->mode & FMODE_READ) +retry: + if (mode & FMODE_READ) r = 1; - if (HOSTFS_I(ino)->mode & FMODE_WRITE) + if (mode & FMODE_WRITE) w = 1; if (w) r = 1; - name = dentry_name(file->f_path.dentry, 0); + name = dentry_name(file->f_path.dentry); if (name == NULL) return -ENOMEM; fd = open_file(name, r, w, append); - kfree(name); + __putname(name); if (fd < 0) return fd; - FILE_HOSTFS_I(file)->fd = fd; + + mutex_lock(&open_mutex); + /* somebody else had handled it first? */ + if ((mode & HOSTFS_I(ino)->mode) == mode) { + mutex_unlock(&open_mutex); + return 0; + } + if ((mode | HOSTFS_I(ino)->mode) != mode) { + mode |= HOSTFS_I(ino)->mode; + mutex_unlock(&open_mutex); + close_file(&fd); + goto retry; + } + if (HOSTFS_I(ino)->fd == -1) { + HOSTFS_I(ino)->fd = fd; + } else { + err = replace_file(fd, HOSTFS_I(ino)->fd); + close_file(&fd); + if (err < 0) { + mutex_unlock(&open_mutex); + return err; + } + } + HOSTFS_I(ino)->mode = mode; + mutex_unlock(&open_mutex); return 0; } @@ -544,54 +492,50 @@ static const struct address_space_operations hostfs_aops = { .write_end = hostfs_write_end, }; -static int init_inode(struct inode *inode, struct dentry *dentry) +static int read_name(struct inode *ino, char *name) { - char *name; - int type, err = -ENOMEM; - int maj, min; - dev_t rdev = 0; + dev_t rdev; + struct hostfs_stat st; + int err = stat_file(name, &st, -1); + if (err) + return err; - if (dentry) { - name = dentry_name(dentry, 0); - if (name == NULL) - goto out; - type = file_type(name, &maj, &min); - /* Reencode maj and min with the kernel encoding.*/ - rdev = MKDEV(maj, min); - kfree(name); - } - else type = OS_TYPE_DIR; + /* Reencode maj and min with the kernel encoding.*/ + rdev = MKDEV(st.maj, st.min); - err = 0; - if (type == OS_TYPE_SYMLINK) - inode->i_op = &page_symlink_inode_operations; - else if (type == OS_TYPE_DIR) - inode->i_op = &hostfs_dir_iops; - else inode->i_op = &hostfs_iops; - - if (type == OS_TYPE_DIR) inode->i_fop = &hostfs_dir_fops; - else inode->i_fop = &hostfs_file_fops; - - if (type == OS_TYPE_SYMLINK) - inode->i_mapping->a_ops = &hostfs_link_aops; - else inode->i_mapping->a_ops = &hostfs_aops; - - switch (type) { - case OS_TYPE_CHARDEV: - init_special_inode(inode, S_IFCHR, rdev); + switch (st.mode & S_IFMT) { + case S_IFLNK: + ino->i_op = &hostfs_link_iops; break; - case OS_TYPE_BLOCKDEV: - init_special_inode(inode, S_IFBLK, rdev); + case S_IFDIR: + ino->i_op = &hostfs_dir_iops; + ino->i_fop = &hostfs_dir_fops; break; - case OS_TYPE_FIFO: - init_special_inode(inode, S_IFIFO, 0); + case S_IFCHR: + case S_IFBLK: + case S_IFIFO: + case S_IFSOCK: + init_special_inode(ino, st.mode & S_IFMT, rdev); + ino->i_op = &hostfs_iops; break; - case OS_TYPE_SOCK: - init_special_inode(inode, S_IFSOCK, 0); - break; - } - out: - return err; + + default: + ino->i_op = &hostfs_iops; + ino->i_fop = &hostfs_file_fops; + ino->i_mapping->a_ops = &hostfs_aops; + } + + ino->i_ino = st.ino; + ino->i_mode = st.mode; + ino->i_nlink = st.nlink; + ino->i_uid = st.uid; + ino->i_gid = st.gid; + ino->i_atime = st.atime; + ino->i_mtime = st.mtime; + ino->i_ctime = st.ctime; + ino->i_size = st.size; + ino->i_blocks = st.blocks; + return 0; } int hostfs_create(struct inode *dir, struct dentry *dentry, int mode, @@ -607,12 +551,8 @@ int hostfs_create(struct inode *dir, struct dentry *dentry, int mode, goto out; } - error = init_inode(inode, dentry); - if (error) - goto out_put; - error = -ENOMEM; - name = dentry_name(dentry, 0); + name = dentry_name(dentry); if (name == NULL) goto out_put; @@ -622,9 +562,10 @@ int hostfs_create(struct inode *dir, struct dentry *dentry, int mode, mode & S_IROTH, mode & S_IWOTH, mode & S_IXOTH); if (fd < 0) error = fd; - else error = read_name(inode, name); + else + error = read_name(inode, name); - kfree(name); + __putname(name); if (error) goto out_put; @@ -652,17 +593,14 @@ struct dentry *hostfs_lookup(struct inode *ino, struct dentry *dentry, goto out; } - err = init_inode(inode, dentry); - if (err) - goto out_put; - err = -ENOMEM; - name = dentry_name(dentry, 0); + name = dentry_name(dentry); if (name == NULL) goto out_put; err = read_name(inode, name); - kfree(name); + + __putname(name); if (err == -ENOENT) { iput(inode); inode = NULL; @@ -680,36 +618,21 @@ struct dentry *hostfs_lookup(struct inode *ino, struct dentry *dentry, return ERR_PTR(err); } -static char *inode_dentry_name(struct inode *ino, struct dentry *dentry) -{ - char *file; - int len; - - file = inode_name(ino, dentry->d_name.len + 1); - if (file == NULL) - return NULL; - strcat(file, "/"); - len = strlen(file); - strncat(file, dentry->d_name.name, dentry->d_name.len); - file[len + dentry->d_name.len] = '\0'; - return file; -} - int hostfs_link(struct dentry *to, struct inode *ino, struct dentry *from) { char *from_name, *to_name; int err; - if ((from_name = inode_dentry_name(ino, from)) == NULL) + if ((from_name = dentry_name(from)) == NULL) return -ENOMEM; - to_name = dentry_name(to, 0); + to_name = dentry_name(to); if (to_name == NULL) { - kfree(from_name); + __putname(from_name); return -ENOMEM; } err = link_file(to_name, from_name); - kfree(from_name); - kfree(to_name); + __putname(from_name); + __putname(to_name); return err; } @@ -718,13 +641,14 @@ int hostfs_unlink(struct inode *ino, struct dentry *dentry) char *file; int err; - if ((file = inode_dentry_name(ino, dentry)) == NULL) - return -ENOMEM; if (append) return -EPERM; + if ((file = dentry_name(dentry)) == NULL) + return -ENOMEM; + err = unlink_file(file); - kfree(file); + __putname(file); return err; } @@ -733,10 +657,10 @@ int hostfs_symlink(struct inode *ino, struct dentry *dentry, const char *to) char *file; int err; - if ((file = inode_dentry_name(ino, dentry)) == NULL) + if ((file = dentry_name(dentry)) == NULL) return -ENOMEM; err = make_symlink(file, to); - kfree(file); + __putname(file); return err; } @@ -745,10 +669,10 @@ int hostfs_mkdir(struct inode *ino, struct dentry *dentry, int mode) char *file; int err; - if ((file = inode_dentry_name(ino, dentry)) == NULL) + if ((file = dentry_name(dentry)) == NULL) return -ENOMEM; err = do_mkdir(file, mode); - kfree(file); + __putname(file); return err; } @@ -757,10 +681,10 @@ int hostfs_rmdir(struct inode *ino, struct dentry *dentry) char *file; int err; - if ((file = inode_dentry_name(ino, dentry)) == NULL) + if ((file = dentry_name(dentry)) == NULL) return -ENOMEM; err = do_rmdir(file); - kfree(file); + __putname(file); return err; } @@ -776,22 +700,20 @@ int hostfs_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t dev) goto out; } - err = init_inode(inode, dentry); - if (err) - goto out_put; - err = -ENOMEM; - name = dentry_name(dentry, 0); + name = dentry_name(dentry); if (name == NULL) goto out_put; init_special_inode(inode, mode, dev); err = do_mknod(name, mode, MAJOR(dev), MINOR(dev)); - if (err) + if (!err) goto out_free; err = read_name(inode, name); - kfree(name); + __putname(name); + if (err) + goto out_put; if (err) goto out_put; @@ -799,7 +721,7 @@ int hostfs_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t dev) return 0; out_free: - kfree(name); + __putname(name); out_put: iput(inode); out: @@ -812,15 +734,15 @@ int hostfs_rename(struct inode *from_ino, struct dentry *from, char *from_name, *to_name; int err; - if ((from_name = inode_dentry_name(from_ino, from)) == NULL) + if ((from_name = dentry_name(from)) == NULL) return -ENOMEM; - if ((to_name = inode_dentry_name(to_ino, to)) == NULL) { - kfree(from_name); + if ((to_name = dentry_name(to)) == NULL) { + __putname(from_name); return -ENOMEM; } err = rename_file(from_name, to_name); - kfree(from_name); - kfree(to_name); + __putname(from_name); + __putname(to_name); return err; } @@ -832,7 +754,7 @@ int hostfs_permission(struct inode *ino, int desired) if (desired & MAY_READ) r = 1; if (desired & MAY_WRITE) w = 1; if (desired & MAY_EXEC) x = 1; - name = inode_name(ino, 0); + name = inode_name(ino); if (name == NULL) return -ENOMEM; @@ -841,7 +763,7 @@ int hostfs_permission(struct inode *ino, int desired) err = 0; else err = access_file(name, r, w, x); - kfree(name); + __putname(name); if (!err) err = generic_permission(ino, desired, NULL); return err; @@ -849,13 +771,14 @@ int hostfs_permission(struct inode *ino, int desired) int hostfs_setattr(struct dentry *dentry, struct iattr *attr) { + struct inode *inode = dentry->d_inode; struct hostfs_iattr attrs; char *name; int err; - int fd = HOSTFS_I(dentry->d_inode)->fd; + int fd = HOSTFS_I(inode)->fd; - err = inode_change_ok(dentry->d_inode, attr); + err = inode_change_ok(inode, attr); if (err) return err; @@ -897,15 +820,26 @@ int hostfs_setattr(struct dentry *dentry, struct iattr *attr) if (attr->ia_valid & ATTR_MTIME_SET) { attrs.ia_valid |= HOSTFS_ATTR_MTIME_SET; } - name = dentry_name(dentry, 0); + name = dentry_name(dentry); if (name == NULL) return -ENOMEM; err = set_attr(name, &attrs, fd); - kfree(name); + __putname(name); if (err) return err; - return inode_setattr(dentry->d_inode, attr); + if ((attr->ia_valid & ATTR_SIZE) && + attr->ia_size != i_size_read(inode)) { + int error; + + error = vmtruncate(inode, attr->ia_size); + if (err) + return err; + } + + setattr_copy(inode, attr); + mark_inode_dirty(inode); + return 0; } static const struct inode_operations hostfs_iops = { @@ -935,32 +869,41 @@ static const struct inode_operations hostfs_dir_iops = { .setattr = hostfs_setattr, }; -int hostfs_link_readpage(struct file *file, struct page *page) -{ - char *buffer, *name; - int err; - - buffer = kmap(page); - name = inode_name(page->mapping->host, 0); - if (name == NULL) - return -ENOMEM; - err = hostfs_do_readlink(name, buffer, PAGE_CACHE_SIZE); - kfree(name); - if (err == PAGE_CACHE_SIZE) - err = -E2BIG; - else if (err > 0) { - flush_dcache_page(page); - SetPageUptodate(page); - if (PageError(page)) ClearPageError(page); - err = 0; +static void *hostfs_follow_link(struct dentry *dentry, struct nameidata *nd) +{ + char *link = __getname(); + if (link) { + char *path = dentry_name(dentry); + int err = -ENOMEM; + if (path) { + int err = hostfs_do_readlink(path, link, PATH_MAX); + if (err == PATH_MAX) + err = -E2BIG; + __putname(path); + } + if (err < 0) { + __putname(link); + link = ERR_PTR(err); + } + } else { + link = ERR_PTR(-ENOMEM); } - kunmap(page); - unlock_page(page); - return err; + + nd_set_link(nd, link); + return NULL; } -static const struct address_space_operations hostfs_link_aops = { - .readpage = hostfs_link_readpage, +static void hostfs_put_link(struct dentry *dentry, struct nameidata *nd, void *cookie) +{ + char *s = nd_get_link(nd); + if (!IS_ERR(s)) + __putname(s); +} + +static const struct inode_operations hostfs_link_iops = { + .readlink = generic_readlink, + .follow_link = hostfs_follow_link, + .put_link = hostfs_put_link, }; static int hostfs_fill_sb_common(struct super_block *sb, void *d, int silent) @@ -980,49 +923,41 @@ static int hostfs_fill_sb_common(struct super_block *sb, void *d, int silent) req_root = ""; err = -ENOMEM; - host_root_path = kmalloc(strlen(root_ino) + 1 - + strlen(req_root) + 1, GFP_KERNEL); + sb->s_fs_info = host_root_path = + kmalloc(strlen(root_ino) + strlen(req_root) + 2, GFP_KERNEL); if (host_root_path == NULL) goto out; sprintf(host_root_path, "%s/%s", root_ino, req_root); - root_inode = hostfs_iget(sb); - if (IS_ERR(root_inode)) { - err = PTR_ERR(root_inode); - goto out_free; - } + root_inode = new_inode(sb); + if (!root_inode) + goto out; - err = init_inode(root_inode, NULL); + err = read_name(root_inode, host_root_path); if (err) goto out_put; - HOSTFS_I(root_inode)->host_filename = host_root_path; - /* - * Avoid that in the error path, iput(root_inode) frees again - * host_root_path through hostfs_destroy_inode! - */ - host_root_path = NULL; + if (S_ISLNK(root_inode->i_mode)) { + char *name = follow_link(host_root_path); + if (IS_ERR(name)) + err = PTR_ERR(name); + else + err = read_name(root_inode, name); + kfree(name); + if (err) + goto out_put; + } err = -ENOMEM; sb->s_root = d_alloc_root(root_inode); if (sb->s_root == NULL) goto out_put; - err = hostfs_read_inode(root_inode); - if (err) { - /* No iput in this case because the dput does that for us */ - dput(sb->s_root); - sb->s_root = NULL; - goto out; - } - return 0; out_put: iput(root_inode); -out_free: - kfree(host_root_path); out: return err; } @@ -1034,11 +969,17 @@ static int hostfs_read_sb(struct file_system_type *type, return get_sb_nodev(type, flags, data, hostfs_fill_sb_common, mnt); } +static void hostfs_kill_sb(struct super_block *s) +{ + kill_anon_super(s); + kfree(s->s_fs_info); +} + static struct file_system_type hostfs_type = { .owner = THIS_MODULE, .name = "hostfs", .get_sb = hostfs_read_sb, - .kill_sb = kill_anon_super, + .kill_sb = hostfs_kill_sb, .fs_flags = 0, }; 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