inode.c

这是Linux系统下的对UDF文件系统新增的功能

/*
 * inode.c
 *
 * PURPOSE
 *  Inode handling routines for the OSTA-UDF(tm) filesystem.
 *
 * CONTACTS
 *  E-mail regarding any portion of the Linux UDF file system should be
 *  directed to the development team mailing list (run by majordomo):
 *    [e-mail]
 *
 * COPYRIGHT
 *  This file is distributed under the terms of the GNU General Public
 *  License (GPL). Copies of the GPL can be obtained from:
 *    ftp://prep.ai.mit.edu/pub/gnu/GPL
 *  Each contributing author retains all rights to their own work.
 *
 *  (C) 1998 Dave Boynton
 *  (C) 1998-2003 Ben Fennema
 *  (C) 1999-2000 Stelias Computing Inc
 *
 * HISTORY
 *
 *  10/04/98 dgb  Added rudimentary directory functions
 *  10/07/98      Fully working udf_block_map! It works!
 *  11/25/98      bmap altered to better support extents
 *  12/06/98 blf  partition support in udf_iget, udf_block_map and udf_read_inode
 *  12/12/98      rewrote udf_block_map to handle next extents and descs across
 *                block boundaries (which is not actually allowed)
 *  12/20/98      added support for strategy 4096
 *  03/07/99      rewrote udf_block_map (again)
 *                New funcs, inode_bmap, udf_next_aext
 *  04/19/99      Support for writing device EA's for major/minor #
 */

#include "udfdecl.h"
#include <linux/mm.h>
#include <linux/smp_lock.h>
#include <linux/module.h>
#include <linux/pagemap.h>
#include <linux/buffer_head.h>
#include <linux/writeback.h>
#include <linux/slab.h>

#include "udf_i.h"
#include "udf_sb.h"

MODULE_AUTHOR("Ben Fennema");
MODULE_DESCRIPTION("Universal Disk Format Filesystem");
MODULE_LICENSE("GPL");

#define EXTENT_MERGE_SIZE 5

static mode_t udf_convert_permissions(struct fileEntry *);
static int udf_update_inode(struct inode *, int);
static void udf_fill_inode(struct inode *, struct buffer_head *);
static struct buffer_head *inode_getblk(struct inode *, long, int *, long *, int *);
static void udf_split_extents(struct inode *, int *, int, int,
	long_ad [EXTENT_MERGE_SIZE], int *);
static void udf_prealloc_extents(struct inode *, int, int,
	 long_ad [EXTENT_MERGE_SIZE], int *);
static void udf_merge_extents(struct inode *,
	 long_ad [EXTENT_MERGE_SIZE], int *);
static void udf_update_extents(struct inode *,
	long_ad [EXTENT_MERGE_SIZE], int, int,
	lb_addr, uint32_t, struct buffer_head **);
static int udf_get_block(struct inode *, sector_t, struct buffer_head *, int);

/*
 * udf_put_inode
 *
 * PURPOSE
 *
 * DESCRIPTION
 *	This routine is called whenever the kernel no longer needs the inode.
 *
 * HISTORY
 *	July 1, 1997 - Andrew E. Mileski
 *	Written, tested, and released.
 *
 *  Called at each iput()
 */
void udf_put_inode(struct inode * inode)
{
	if (!(inode->i_sb->s_flags & MS_RDONLY))
	{
		lock_kernel();
		udf_discard_prealloc(inode);
		unlock_kernel();
	}
}

/*
 * udf_delete_inode
 *
 * PURPOSE
 *	Clean-up before the specified inode is destroyed.
 *
 * DESCRIPTION
 *	This routine is called when the kernel destroys an inode structure
 *	ie. when iput() finds i_count == 0.
 *
 * HISTORY
 *	July 1, 1997 - Andrew E. Mileski
 *	Written, tested, and released.
 *
 *  Called at the last iput() if i_nlink is zero.
 */
void udf_delete_inode(struct inode * inode)
{
	if (is_bad_inode(inode))
		goto no_delete;

	inode->i_size = 0;
	udf_truncate(inode);
	lock_kernel();

	udf_update_inode(inode, IS_SYNC(inode));
	udf_free_inode(inode);

	unlock_kernel();
	return;
no_delete:
	clear_inode(inode);
}

void udf_clear_inode(struct inode *inode)
{
	kfree(UDF_I_DATA(inode));
	UDF_I_DATA(inode) = NULL;
}

static int udf_writepage(struct page *page, struct writeback_control *wbc)
{
	return block_write_full_page(page, udf_get_block, wbc);
}

static int udf_readpage(struct file *file, struct page *page)
{
	return block_read_full_page(page, udf_get_block);
}

static int udf_prepare_write(struct file *file, struct page *page, unsigned from, unsigned to)
{
	return block_prepare_write(page, from, to, udf_get_block);
}

static sector_t udf_bmap(struct address_space *mapping, sector_t block)
{
	return generic_block_bmap(mapping,block,udf_get_block);
}

struct address_space_operations udf_aops = {
	.readpage		= udf_readpage,
	.writepage		= udf_writepage,
	.sync_page		= block_sync_page,
	.prepare_write		= udf_prepare_write,
	.commit_write		= generic_commit_write,
	.bmap			= udf_bmap,
};

void udf_expand_file_adinicb(struct inode * inode, int newsize, int * err)
{
	struct page *page;
	char *kaddr;
	struct writeback_control udf_wbc = {
		.sync_mode = WB_SYNC_NONE,
		.nr_to_write = 1,
	};

	/* from now on we have normal address_space methods */
	inode->i_data.a_ops = &udf_aops;

	if (!UDF_I_LENALLOC(inode))
	{
		if (UDF_QUERY_FLAG(inode->i_sb, UDF_FLAG_USE_SHORT_AD))
			UDF_I_ALLOCTYPE(inode) = ICBTAG_FLAG_AD_SHORT;
		else
			UDF_I_ALLOCTYPE(inode) = ICBTAG_FLAG_AD_LONG;
		mark_inode_dirty(inode);
		return;
	}

	page = grab_cache_page(inode->i_mapping, 0);
	if (!PageLocked(page))
		PAGE_BUG(page);
	if (!PageUptodate(page))
	{
		kaddr = kmap(page);
		memset(kaddr + UDF_I_LENALLOC(inode), 0x00,
			PAGE_CACHE_SIZE - UDF_I_LENALLOC(inode));
		memcpy(kaddr, UDF_I_DATA(inode) + UDF_I_LENEATTR(inode),
			UDF_I_LENALLOC(inode));
		flush_dcache_page(page);
		SetPageUptodate(page);
		kunmap(page);
	}
	memset(UDF_I_DATA(inode) + UDF_I_LENEATTR(inode), 0x00,
		UDF_I_LENALLOC(inode));
	UDF_I_LENALLOC(inode) = 0;
	if (UDF_QUERY_FLAG(inode->i_sb, UDF_FLAG_USE_SHORT_AD))
		UDF_I_ALLOCTYPE(inode) = ICBTAG_FLAG_AD_SHORT;
	else
		UDF_I_ALLOCTYPE(inode) = ICBTAG_FLAG_AD_LONG;

	inode->i_data.a_ops->writepage(page, &udf_wbc);
	page_cache_release(page);

	mark_inode_dirty(inode);
}

struct buffer_head * udf_expand_dir_adinicb(struct inode *inode, int *block, int *err)
{
	int newblock;
	struct buffer_head *sbh = NULL, *dbh = NULL;
	lb_addr bloc, eloc;
	uint32_t elen, extoffset;
	uint8_t alloctype;

	struct udf_fileident_bh sfibh, dfibh;
	loff_t f_pos = udf_ext0_offset(inode) >> 2;
	int size = (udf_ext0_offset(inode) + inode->i_size) >> 2;
	struct fileIdentDesc cfi, *sfi, *dfi;

	if (UDF_QUERY_FLAG(inode->i_sb, UDF_FLAG_USE_SHORT_AD))
		alloctype = ICBTAG_FLAG_AD_SHORT;
	else
		alloctype = ICBTAG_FLAG_AD_LONG;

	if (!inode->i_size)
	{
		UDF_I_ALLOCTYPE(inode) = alloctype;
		mark_inode_dirty(inode);
		return NULL;
	}

	/* alloc block, and copy data to it */
	*block = udf_new_block(inode->i_sb, inode,
		UDF_I_LOCATION(inode).partitionReferenceNum,
		UDF_I_LOCATION(inode).logicalBlockNum, err);

	if (!(*block))
		return NULL;
	newblock = udf_get_pblock(inode->i_sb, *block,
		UDF_I_LOCATION(inode).partitionReferenceNum, 0);
	if (!newblock)
		return NULL;
	dbh = udf_tgetblk(inode->i_sb, newblock);
	if (!dbh)
		return NULL;
	lock_buffer(dbh);
	memset(dbh->b_data, 0x00, inode->i_sb->s_blocksize);
	set_buffer_uptodate(dbh);
	unlock_buffer(dbh);
	mark_buffer_dirty_inode(dbh, inode);

	sfibh.soffset = sfibh.eoffset = (f_pos & ((inode->i_sb->s_blocksize - 1) >> 2)) << 2;
	sbh = sfibh.sbh = sfibh.ebh = NULL;
	dfibh.soffset = dfibh.eoffset = 0;
	dfibh.sbh = dfibh.ebh = dbh;
	while ( (f_pos < size) )
	{
		UDF_I_ALLOCTYPE(inode) = ICBTAG_FLAG_AD_IN_ICB;
		sfi = udf_fileident_read(inode, &f_pos, &sfibh, &cfi, NULL, NULL, NULL, NULL, NULL, NULL);
		if (!sfi)
		{
			udf_release_data(dbh);
			return NULL;
		}
		UDF_I_ALLOCTYPE(inode) = alloctype;
		sfi->descTag.tagLocation = *block;
		dfibh.soffset = dfibh.eoffset;
		dfibh.eoffset += (sfibh.eoffset - sfibh.soffset);
		dfi = (struct fileIdentDesc *)(dbh->b_data + dfibh.soffset);
		if (udf_write_fi(inode, sfi, dfi, &dfibh, sfi->impUse,
			sfi->fileIdent + sfi->lengthOfImpUse))
		{
			UDF_I_ALLOCTYPE(inode) = ICBTAG_FLAG_AD_IN_ICB;
			udf_release_data(dbh);
			return NULL;
		}
	}
	mark_buffer_dirty_inode(dbh, inode);

	memset(UDF_I_DATA(inode) + UDF_I_LENEATTR(inode), 0, UDF_I_LENALLOC(inode));
	UDF_I_LENALLOC(inode) = 0;
	bloc = UDF_I_LOCATION(inode);
	eloc.logicalBlockNum = *block;
	eloc.partitionReferenceNum = UDF_I_LOCATION(inode).partitionReferenceNum;
	elen = inode->i_size;
	UDF_I_LENEXTENTS(inode) = elen;
	extoffset = udf_file_entry_alloc_offset(inode);
	udf_add_aext(inode, &bloc, &extoffset, eloc, elen, &sbh, 0);
	/* UniqueID stuff */

	udf_release_data(sbh);
	mark_inode_dirty(inode);
	return dbh;
}

static int udf_get_block(struct inode *inode, sector_t block, struct buffer_head *bh_result, int create)
{
	int err, new;
	struct buffer_head *bh;
	unsigned long phys;

	if (!create)
	{
		phys = udf_block_map(inode, block);
		if (phys)
			map_bh(bh_result, inode->i_sb, phys);
		return 0;
	}

	err = -EIO;
	new = 0;
	bh = NULL;

	lock_kernel();

	if (block < 0)
		goto abort_negative;

	if (block == UDF_I_NEXT_ALLOC_BLOCK(inode) + 1)
	{
		UDF_I_NEXT_ALLOC_BLOCK(inode) ++;
		UDF_I_NEXT_ALLOC_GOAL(inode) ++;
	}

	err = 0;

	bh = inode_getblk(inode, block, &err, &phys, &new);
	if (bh)
		BUG();
	if (err)
		goto abort;
	if (!phys)
		BUG();

	if (new)
		set_buffer_new(bh_result);
	map_bh(bh_result, inode->i_sb, phys);
abort:
	unlock_kernel();
	return err;

abort_negative:
	udf_warning(inode->i_sb, "udf_get_block", "block < 0");
	goto abort;
}

struct buffer_head * udf_getblk(struct inode * inode, long block,
	int create, int * err)
{
	struct buffer_head dummy;

	dummy.b_state = 0;
	dummy.b_blocknr = -1000;
	*err = udf_get_block(inode, block, &dummy, create);
	if (!*err && buffer_mapped(&dummy))
	{
		struct buffer_head *bh;
		bh = sb_getblk(inode->i_sb, dummy.b_blocknr);
		if (buffer_new(&dummy))
		{
			lock_buffer(bh);
			memset(bh->b_data, 0x00, inode->i_sb->s_blocksize);
			set_buffer_uptodate(bh);
			unlock_buffer(bh);
			mark_buffer_dirty_inode(bh, inode);
		}
		return bh;
	}
	return NULL;
}

static struct buffer_head * inode_getblk(struct inode * inode, long block,
	int *err, long *phys, int *new)
{
	struct buffer_head *pbh = NULL, *cbh = NULL, *nbh = NULL, *result = NULL;
	long_ad laarr[EXTENT_MERGE_SIZE];
	uint32_t pextoffset = 0, cextoffset = 0, nextoffset = 0;
	int count = 0, startnum = 0, endnum = 0;
	uint32_t elen = 0;
	lb_addr eloc, pbloc, cbloc, nbloc;
	int c = 1;
	uint64_t lbcount = 0, b_off = 0;
	uint32_t newblocknum, newblock, offset = 0;
	int8_t etype;
	int goal = 0, pgoal = UDF_I_LOCATION(inode).logicalBlockNum;
	char lastblock = 0;

	pextoffset = cextoffset = nextoffset = udf_file_entry_alloc_offset(inode);
	b_off = (uint64_t)block << inode->i_sb->s_blocksize_bits;
	pbloc = cbloc = nbloc = UDF_I_LOCATION(inode);

	/* find the extent which contains the block we are looking for.
       alternate between laarr[0] and laarr[1] for locations of the
       current extent, and the previous extent */
	do
	{
		if (pbh != cbh)
		{
			udf_release_data(pbh);
			atomic_inc(&cbh->b_count);
			pbh = cbh;
		}
		if (cbh != nbh)
		{
			udf_release_data(cbh);
			atomic_inc(&nbh->b_count);
			cbh = nbh;
		}

		lbcount += elen;

		pbloc = cbloc;
		cbloc = nbloc;

		pextoffset = cextoffset;
		cextoffset = nextoffset;

		if ((etype = udf_next_aext(inode, &nbloc, &nextoffset, &eloc, &elen, &nbh, 1)) == -1)
			break;

		c = !c;

		laarr[c].extLength = (etype << 30) | elen;
		laarr[c].extLocation = eloc;

		if (etype != (EXT_NOT_RECORDED_NOT_ALLOCATED >> 30))
			pgoal = eloc.logicalBlockNum +
				((elen + inode->i_sb->s_blocksize - 1) >>
				inode->i_sb->s_blocksize_bits);

		count ++;
	} while (lbcount + elen <= b_off);

	b_off -= lbcount;
	offset = b_off >> inode->i_sb->s_blocksize_bits;

	/* if the extent is allocated and recorded, return the block
       if the extent is not a multiple of the blocksize, round up */

	if (etype == (EXT_RECORDED_ALLOCATED >> 30))
	{
		if (elen & (inode->i_sb->s_blocksize - 1))
		{
			elen = EXT_RECORDED_ALLOCATED |
				((elen + inode->i_sb->s_blocksize - 1) &
				~(inode->i_sb->s_blocksize - 1));
			etype = udf_write_aext(inode, nbloc, &cextoffset, eloc, elen, nbh, 1);
		}
		udf_release_data(pbh);
		udf_release_data(cbh);
		udf_release_data(nbh);
		newblock = udf_get_lb_pblock(inode->i_sb, eloc, offset);
		*phys = newblock;
		return NULL;
	}

	if (etype == -1)
	{
		endnum = startnum = ((count > 1) ? 1 : count);
		if (laarr[c].extLength & (inode->i_sb->s_blocksize - 1))
		{
			laarr[c].extLength =
				(laarr[c].extLength & UDF_EXTENT_FLAG_MASK) |
				(((laarr[c].extLength & UDF_EXTENT_LENGTH_MASK) +
					inode->i_sb->s_blocksize - 1) &
				~(inode->i_sb->s_blocksize - 1));
			UDF_I_LENEXTENTS(inode) =
				(UDF_I_LENEXTENTS(inode) + inode->i_sb->s_blocksize - 1) &
					~(inode->i_sb->s_blocksize - 1);
		}
		c = !c;
		laarr[c].extLength = EXT_NOT_RECORDED_NOT_ALLOCATED |
			((offset + 1) << inode->i_sb->s_blocksize_bits);
		memset(&laarr[c].extLocation, 0x00, sizeof(lb_addr));
		count ++;
		endnum ++;
		lastblock = 1;
	}
	else
		endnum = startnum = ((count > 2) ? 2 : count);

	/* if the current extent is in position 0, swap it with the previous */
	if (!c && count != 1)
	{
		laarr[2] = laarr[0];
		laarr[0] = laarr[1];
		laarr[1] = laarr[2];
		c = 1;
	}

	/* if the current block is located in a extent, read the next extent */
	if (etype != -1)
	{
		if ((etype = udf_next_aext(inode, &nbloc, &nextoffset, &eloc, &elen, &nbh, 0)) != -1)
		{
			laarr[c+1].extLength = (etype << 30) | elen;
			laarr[c+1].extLocation = eloc;
			count ++;
			startnum ++;
			endnum ++;
		}
		else
			lastblock = 1;
	}
	udf_release_data(cbh);
	udf_release_data(nbh);

	/* if the current extent is not recorded but allocated, get the
		block in the extent corresponding to the requested block */
	if ((laarr[c].extLength >> 30) == (EXT_NOT_RECORDED_ALLOCATED >> 30))
		newblocknum = laarr[c].extLocation.logicalBlockNum + offset;
	else /* otherwise, allocate a new block */
	{
		if (UDF_I_NEXT_ALLOC_BLOCK(inode) == block)
			goal = UDF_I_NEXT_ALLOC_GOAL(inode);