| /* |
| * Copyright 2000 by Hans Reiser, licensing governed by reiserfs/README |
| */ |
| |
| #include <linux/fs.h> |
| #include <linux/reiserfs_fs.h> |
| #include <linux/sched.h> |
| #include <asm/uaccess.h> |
| #include <linux/smp_lock.h> |
| #include <linux/locks.h> |
| |
| /* |
| ** reiserfs_ioctl - handler for ioctl for inode |
| ** supported commands: |
| ** 1) REISERFS_IOC_UNPACK - try to unpack tail from direct item into indirect |
| ** and prevent packing file (argument arg has to be non-zero) |
| ** 2) That's all for a while ... |
| */ |
| int reiserfs_ioctl (struct inode * inode, struct file * filp, unsigned int cmd, |
| unsigned long arg) |
| { |
| switch (cmd) { |
| case REISERFS_IOC_UNPACK: |
| if (arg) |
| return reiserfs_unpack (inode, filp); |
| |
| default: |
| return -ENOTTY; |
| } |
| } |
| |
| /* |
| ** reiserfs_unpack |
| ** Function try to convert tail from direct item into indirect. |
| ** It set up nopack attribute in the inode.u.reiserfs_i.nopack |
| */ |
| int reiserfs_unpack (struct inode * inode, struct file * filp) |
| { |
| int retval = 0; |
| int index ; |
| struct page *page ; |
| unsigned long write_from ; |
| unsigned long blocksize = inode->i_sb->s_blocksize ; |
| |
| if (inode->i_size == 0) { |
| return -EINVAL ; |
| } |
| /* ioctl already done */ |
| if (inode->u.reiserfs_i.nopack) { |
| return 0 ; |
| } |
| lock_kernel(); |
| |
| /* we need to make sure nobody is changing the file size beneath |
| ** us |
| */ |
| down(&inode->i_sem) ; |
| |
| write_from = inode->i_size & (blocksize - 1) ; |
| /* if we are on a block boundary, we are already unpacked. */ |
| if ( write_from == 0) { |
| inode->u.reiserfs_i.nopack = 1; |
| goto out ; |
| } |
| |
| /* we unpack by finding the page with the tail, and calling |
| ** reiserfs_prepare_write on that page. This will force a |
| ** reiserfs_get_block to unpack the tail for us. |
| */ |
| index = inode->i_size >> PAGE_CACHE_SHIFT ; |
| page = grab_cache_page(inode->i_mapping, index) ; |
| retval = -ENOMEM; |
| if (!page) { |
| goto out ; |
| } |
| retval = reiserfs_prepare_write(NULL, page, write_from, blocksize) ; |
| if (retval) |
| goto out_unlock ; |
| |
| /* conversion can change page contents, must flush */ |
| flush_dcache_page(page) ; |
| inode->u.reiserfs_i.nopack = 1; |
| kunmap(page) ; /* mapped by prepare_write */ |
| |
| out_unlock: |
| UnlockPage(page) ; |
| page_cache_release(page) ; |
| |
| out: |
| up(&inode->i_sem) ; |
| unlock_kernel(); |
| return retval; |
| } |