X-Git-Url: http://ftp.safe.ca/?a=blobdiff_plain;f=fs%2Fanon_inodes.c;h=9f0bf13291e53de00b01fe6b12218cb4c3b9f664;hb=1b644b6e6f6160ae35ce4b52c2ca89ed3e356e18;hp=1a4eee620b0d91aea2bc46a1b59484eecb572aac;hpb=7d9dbca34240ebb6ff88d8a29c6c7bffd098f0c1;p=safe%2Fjmp%2Flinux-2.6 diff --git a/fs/anon_inodes.c b/fs/anon_inodes.c index 1a4eee6..9f0bf13 100644 --- a/fs/anon_inodes.c +++ b/fs/anon_inodes.c @@ -8,8 +8,10 @@ * */ +#include #include #include +#include #include #include #include @@ -33,14 +35,13 @@ static int anon_inodefs_get_sb(struct file_system_type *fs_type, int flags, mnt); } -static int anon_inodefs_delete_dentry(struct dentry *dentry) +/* + * anon_inodefs_dname() is called from d_path(). + */ +static char *anon_inodefs_dname(struct dentry *dentry, char *buffer, int buflen) { - /* - * We faked vfs to believe the dentry was hashed when we created it. - * Now we restore the flag so that dput() will work correctly. - */ - dentry->d_flags |= DCACHE_UNHASHED; - return 1; + return dynamic_dname(dentry, buffer, buflen, "anon_inode:%s", + dentry->d_name.name); } static struct file_system_type anon_inode_fs_type = { @@ -48,8 +49,21 @@ static struct file_system_type anon_inode_fs_type = { .get_sb = anon_inodefs_get_sb, .kill_sb = kill_anon_super, }; -static struct dentry_operations anon_inodefs_dentry_operations = { - .d_delete = anon_inodefs_delete_dentry, +static const struct dentry_operations anon_inodefs_dentry_operations = { + .d_dname = anon_inodefs_dname, +}; + +/* + * nop .set_page_dirty method so that people can use .page_mkwrite on + * anon inodes. + */ +static int anon_set_page_dirty(struct page *page) +{ + return 0; +}; + +static const struct address_space_operations anon_aops = { + .set_page_dirty = anon_set_page_dirty, }; /** @@ -64,25 +78,24 @@ static struct dentry_operations anon_inodefs_dentry_operations = { * * Creates a new file by hooking it on a single inode. This is useful for files * that do not need to have a full-fledged inode in order to operate correctly. - * All the files created with anon_inode_getfd() will share a single inode, + * All the files created with anon_inode_getfile() will share a single inode, * hence saving memory and avoiding code duplication for the file/inode/dentry - * setup. Returns new descriptor or -error. + * setup. Returns the newly created file* or an error pointer. */ -int anon_inode_getfd(const char *name, const struct file_operations *fops, - void *priv, int flags) +struct file *anon_inode_getfile(const char *name, + const struct file_operations *fops, + void *priv, int flags) { struct qstr this; - struct dentry *dentry; + struct path path; struct file *file; - int error, fd; + int error; if (IS_ERR(anon_inode_inode)) - return -ENODEV; + return ERR_PTR(-ENODEV); - error = get_unused_fd_flags(flags); - if (error < 0) - return error; - fd = error; + if (fops->owner && !try_module_get(fops->owner)) + return ERR_PTR(-ENOENT); /* * Link the inode to a directory entry by creating a unique name @@ -92,10 +105,11 @@ int anon_inode_getfd(const char *name, const struct file_operations *fops, this.name = name; this.len = strlen(name); this.hash = 0; - dentry = d_alloc(anon_inode_mnt->mnt_sb->s_root, &this); - if (!dentry) - goto err_put_unused_fd; + path.dentry = d_alloc(anon_inode_mnt->mnt_sb->s_root, &this); + if (!path.dentry) + goto err_module; + path.mnt = mntget(anon_inode_mnt); /* * We know the anon_inode inode count is always greater than zero, * so we can avoid doing an igrab() and we can use an open-coded @@ -103,29 +117,66 @@ int anon_inode_getfd(const char *name, const struct file_operations *fops, */ atomic_inc(&anon_inode_inode->i_count); - dentry->d_op = &anon_inodefs_dentry_operations; - /* Do not publish this dentry inside the global dentry hash table */ - dentry->d_flags &= ~DCACHE_UNHASHED; - d_instantiate(dentry, anon_inode_inode); + path.dentry->d_op = &anon_inodefs_dentry_operations; + d_instantiate(path.dentry, anon_inode_inode); error = -ENFILE; - file = alloc_file(anon_inode_mnt, dentry, - FMODE_READ | FMODE_WRITE, fops); + file = alloc_file(&path, OPEN_FMODE(flags), fops); if (!file) goto err_dput; file->f_mapping = anon_inode_inode->i_mapping; file->f_pos = 0; - file->f_flags = O_RDWR; + file->f_flags = flags & (O_ACCMODE | O_NONBLOCK); file->f_version = 0; file->private_data = priv; + return file; + +err_dput: + path_put(&path); +err_module: + module_put(fops->owner); + return ERR_PTR(error); +} +EXPORT_SYMBOL_GPL(anon_inode_getfile); + +/** + * anon_inode_getfd - creates a new file instance by hooking it up to an + * anonymous inode, and a dentry that describe the "class" + * of the file + * + * @name: [in] name of the "class" of the new file + * @fops: [in] file operations for the new file + * @priv: [in] private data for the new file (will be file's private_data) + * @flags: [in] flags + * + * Creates a new file by hooking it on a single inode. This is useful for files + * that do not need to have a full-fledged inode in order to operate correctly. + * All the files created with anon_inode_getfd() will share a single inode, + * hence saving memory and avoiding code duplication for the file/inode/dentry + * setup. Returns new descriptor or an error code. + */ +int anon_inode_getfd(const char *name, const struct file_operations *fops, + void *priv, int flags) +{ + int error, fd; + struct file *file; + + error = get_unused_fd_flags(flags); + if (error < 0) + return error; + fd = error; + + file = anon_inode_getfile(name, fops, priv, flags); + if (IS_ERR(file)) { + error = PTR_ERR(file); + goto err_put_unused_fd; + } fd_install(fd, file); return fd; -err_dput: - dput(dentry); err_put_unused_fd: put_unused_fd(fd); return error; @@ -146,6 +197,8 @@ static struct inode *anon_inode_mkinode(void) inode->i_fop = &anon_inode_fops; + inode->i_mapping->a_ops = &anon_aops; + /* * Mark the inode dirty from the very beginning, * that way it will never be moved to the dirty @@ -154,8 +207,8 @@ static struct inode *anon_inode_mkinode(void) */ inode->i_state = I_DIRTY; inode->i_mode = S_IRUSR | S_IWUSR; - inode->i_uid = current->fsuid; - inode->i_gid = current->fsgid; + inode->i_uid = current_fsuid(); + inode->i_gid = current_fsgid(); inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME; return inode; }