X-Git-Url: http://ftp.safe.ca/?a=blobdiff_plain;f=fs%2Fanon_inodes.c;h=94f5110c4655167a769088e40e94e3a5159dedeb;hb=c0b4abdd529d8256acc4cf0094db385877f34ae6;hp=edc67486238f353ee58803cf5e829548104496f5;hpb=d6d281684913dabb878e2f53219eed5df2cd867b;p=safe%2Fjmp%2Flinux-2.6 diff --git a/fs/anon_inodes.c b/fs/anon_inodes.c index edc6748..94f5110 100644 --- a/fs/anon_inodes.c +++ b/fs/anon_inodes.c @@ -8,8 +8,10 @@ * */ +#include #include #include +#include #include #include #include @@ -48,54 +50,53 @@ 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 = { +static const struct dentry_operations anon_inodefs_dentry_operations = { .d_delete = anon_inodefs_delete_dentry, }; +/* + * 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, +}; + /** - * anon_inode_getfd - creates a new file instance by hooking it up to and + * 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 * - * @pfd: [out] pointer to the file descriptor - * @dpinode: [out] pointer to the inode - * @pfile: [out] pointer to the file struct * @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) + * @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, by + * 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. + * setup. Returns the newly created file* or an error pointer. */ -int anon_inode_getfd(int *pfd, struct inode **pinode, struct file **pfile, - const char *name, const struct file_operations *fops, - void *priv) +struct file *anon_inode_getfile(const char *name, + const struct file_operations *fops, + void *priv, int flags) { struct qstr this; - struct dentry *dentry; - struct inode *inode; + struct path path; struct file *file; - int error, fd; + int error; if (IS_ERR(anon_inode_inode)) - return -ENODEV; - file = get_empty_filp(); - if (!file) - return -ENFILE; + return ERR_PTR(-ENODEV); - inode = igrab(anon_inode_inode); - if (IS_ERR(inode)) { - error = PTR_ERR(inode); - goto err_put_filp; - } - - error = get_unused_fd(); - if (error < 0) - goto err_iput; - 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 @@ -105,46 +106,90 @@ int anon_inode_getfd(int *pfd, struct inode **pinode, struct file **pfile, 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; - dentry->d_op = &anon_inodefs_dentry_operations; + 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 + * atomic_inc(). + */ + atomic_inc(&anon_inode_inode->i_count); + + path.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, inode); + path.dentry->d_flags &= ~DCACHE_UNHASHED; + d_instantiate(path.dentry, anon_inode_inode); - file->f_path.mnt = mntget(anon_inode_mnt); - file->f_path.dentry = dentry; - file->f_mapping = inode->i_mapping; + error = -ENFILE; + file = alloc_file(&path, FMODE_READ | FMODE_WRITE, 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_op = fops; - file->f_mode = FMODE_READ | FMODE_WRITE; + file->f_flags = O_RDWR | (flags & 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); - *pfd = fd; - *pinode = inode; - *pfile = file; - return 0; + return fd; err_put_unused_fd: put_unused_fd(fd); -err_iput: - iput(inode); -err_put_filp: - put_filp(file); return error; } EXPORT_SYMBOL_GPL(anon_inode_getfd); /* - * A single inode exist for all anon_inode files. Contrary to pipes, - * anon_inode inodes has no per-instance data associated, so we can avoid - * the allocation of multiple of them. + * A single inode exists for all anon_inode files. Contrary to pipes, + * anon_inode inodes have no associated per-instance data, so we need + * only allocate one of them. */ static struct inode *anon_inode_mkinode(void) { @@ -155,6 +200,8 @@ 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 @@ -163,8 +210,8 @@ 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; }