Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759106AbYAJPEH (ORCPT ); Thu, 10 Jan 2008 10:04:07 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755680AbYAJPAu (ORCPT ); Thu, 10 Jan 2008 10:00:50 -0500 Received: from filer.fsl.cs.sunysb.edu ([130.245.126.2]:57021 "EHLO filer.fsl.cs.sunysb.edu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757501AbYAJPAl (ORCPT ); Thu, 10 Jan 2008 10:00:41 -0500 From: Erez Zadok To: torvalds@linux-foundation.org, akpm@linux-foundation.org, hch@infradead.org, viro@ftp.linux.org.uk Cc: linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, Erez Zadok Subject: [PATCH 08/29] Unionfs: basic file operations Date: Thu, 10 Jan 2008 09:59:27 -0500 Message-Id: <11999771922373-git-send-email-ezk@cs.sunysb.edu> X-Mailer: git-send-email 1.5.2.2 X-MailKey: Erez_Zadok In-Reply-To: <11999771882152-git-send-email-ezk@cs.sunysb.edu> References: <11999771882152-git-send-email-ezk@cs.sunysb.edu> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 6123 Lines: 206 Includes read, write, mmap, fsync, and fasync. Signed-off-by: Erez Zadok --- fs/unionfs/file.c | 184 +++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 files changed, 184 insertions(+), 0 deletions(-) create mode 100644 fs/unionfs/file.c diff --git a/fs/unionfs/file.c b/fs/unionfs/file.c new file mode 100644 index 0000000..0c424f6 --- /dev/null +++ b/fs/unionfs/file.c @@ -0,0 +1,184 @@ +/* + * Copyright (c) 2003-2007 Erez Zadok + * Copyright (c) 2003-2006 Charles P. Wright + * Copyright (c) 2005-2007 Josef 'Jeff' Sipek + * Copyright (c) 2005-2006 Junjiro Okajima + * Copyright (c) 2005 Arun M. Krishnakumar + * Copyright (c) 2004-2006 David P. Quigley + * Copyright (c) 2003-2004 Mohammad Nayyer Zubair + * Copyright (c) 2003 Puja Gupta + * Copyright (c) 2003 Harikesavan Krishnan + * Copyright (c) 2003-2007 Stony Brook University + * Copyright (c) 2003-2007 The Research Foundation of SUNY + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + */ + +#include "union.h" + +static int unionfs_file_readdir(struct file *file, void *dirent, + filldir_t filldir) +{ + return -ENOTDIR; +} + +static int unionfs_mmap(struct file *file, struct vm_area_struct *vma) +{ + int err = 0; + bool willwrite; + struct file *lower_file; + + unionfs_read_lock(file->f_path.dentry->d_sb, UNIONFS_SMUTEX_PARENT); + + /* This might be deferred to mmap's writepage */ + willwrite = ((vma->vm_flags | VM_SHARED | VM_WRITE) == vma->vm_flags); + err = unionfs_file_revalidate(file, willwrite); + if (unlikely(err)) + goto out; + unionfs_check_file(file); + + /* + * File systems which do not implement ->writepage may use + * generic_file_readonly_mmap as their ->mmap op. If you call + * generic_file_readonly_mmap with VM_WRITE, you'd get an -EINVAL. + * But we cannot call the lower ->mmap op, so we can't tell that + * writeable mappings won't work. Therefore, our only choice is to + * check if the lower file system supports the ->writepage, and if + * not, return EINVAL (the same error that + * generic_file_readonly_mmap returns in that case). + */ + lower_file = unionfs_lower_file(file); + if (willwrite && !lower_file->f_mapping->a_ops->writepage) { + err = -EINVAL; + printk(KERN_ERR "unionfs: branch %d file system does not " + "support writeable mmap\n", fbstart(file)); + } else { + err = generic_file_mmap(file, vma); + if (err) + printk(KERN_ERR + "unionfs: generic_file_mmap failed %d\n", err); + } + +out: + if (!err) { + /* copyup could cause parent dir times to change */ + unionfs_copy_attr_times(file->f_path.dentry->d_parent->d_inode); + unionfs_check_file(file); + } + unionfs_read_unlock(file->f_path.dentry->d_sb); + return err; +} + +int unionfs_fsync(struct file *file, struct dentry *dentry, int datasync) +{ + int bindex, bstart, bend; + struct file *lower_file; + struct dentry *lower_dentry; + struct inode *lower_inode, *inode; + int err = -EINVAL; + + unionfs_read_lock(file->f_path.dentry->d_sb, UNIONFS_SMUTEX_PARENT); + err = unionfs_file_revalidate(file, true); + if (unlikely(err)) + goto out; + unionfs_check_file(file); + + bstart = fbstart(file); + bend = fbend(file); + if (bstart < 0 || bend < 0) + goto out; + + inode = dentry->d_inode; + if (unlikely(!inode)) { + printk(KERN_ERR + "unionfs: null lower inode in unionfs_fsync\n"); + goto out; + } + for (bindex = bstart; bindex <= bend; bindex++) { + lower_inode = unionfs_lower_inode_idx(inode, bindex); + if (!lower_inode || !lower_inode->i_fop->fsync) + continue; + lower_file = unionfs_lower_file_idx(file, bindex); + lower_dentry = unionfs_lower_dentry_idx(dentry, bindex); + mutex_lock(&lower_inode->i_mutex); + err = lower_inode->i_fop->fsync(lower_file, + lower_dentry, + datasync); + mutex_unlock(&lower_inode->i_mutex); + if (err) + goto out; + } + + unionfs_copy_attr_times(inode); + +out: + unionfs_check_file(file); + unionfs_read_unlock(file->f_path.dentry->d_sb); + return err; +} + +int unionfs_fasync(int fd, struct file *file, int flag) +{ + int bindex, bstart, bend; + struct file *lower_file; + struct dentry *dentry; + struct inode *lower_inode, *inode; + int err = 0; + + unionfs_read_lock(file->f_path.dentry->d_sb, UNIONFS_SMUTEX_PARENT); + err = unionfs_file_revalidate(file, true); + if (unlikely(err)) + goto out; + unionfs_check_file(file); + + bstart = fbstart(file); + bend = fbend(file); + if (bstart < 0 || bend < 0) + goto out; + + dentry = file->f_path.dentry; + inode = dentry->d_inode; + if (unlikely(!inode)) { + printk(KERN_ERR + "unionfs: null lower inode in unionfs_fasync\n"); + goto out; + } + for (bindex = bstart; bindex <= bend; bindex++) { + lower_inode = unionfs_lower_inode_idx(inode, bindex); + if (!lower_inode || !lower_inode->i_fop->fasync) + continue; + lower_file = unionfs_lower_file_idx(file, bindex); + mutex_lock(&lower_inode->i_mutex); + err = lower_inode->i_fop->fasync(fd, lower_file, flag); + mutex_unlock(&lower_inode->i_mutex); + if (err) + goto out; + } + + unionfs_copy_attr_times(inode); + +out: + unionfs_check_file(file); + unionfs_read_unlock(file->f_path.dentry->d_sb); + return err; +} + +struct file_operations unionfs_main_fops = { + .llseek = generic_file_llseek, + .read = do_sync_read, + .aio_read = generic_file_aio_read, + .write = do_sync_write, + .aio_write = generic_file_aio_write, + .readdir = unionfs_file_readdir, + .unlocked_ioctl = unionfs_ioctl, + .mmap = unionfs_mmap, + .open = unionfs_open, + .flush = unionfs_flush, + .release = unionfs_file_release, + .fsync = unionfs_fsync, + .fasync = unionfs_fasync, + .splice_read = generic_file_splice_read, + .splice_write = generic_file_splice_write, +}; -- 1.5.2.2 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/