Initial import

1 files changed, 286 insertions, 0 deletions

diff --git a/fs/udf/truncate.c b/fs/udf/truncate.c
new file mode 100644
index 000000000..42b8c5779
--- /dev/null
+++ b/fs/udf/truncate.c
@@ -0,0 +1,286 @@
+/*
+ * truncate.c
+ *
+ * PURPOSE
+ *	Truncate handling routines for the OSTA-UDF(tm) filesystem.
+ *
+ * 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) 1999-2004 Ben Fennema
+ *  (C) 1999 Stelias Computing Inc
+ *
+ * HISTORY
+ *
+ *  02/24/99 blf  Created.
+ *
+ */
+
+#include "udfdecl.h"
+#include <linux/fs.h>
+#include <linux/mm.h>
+
+#include "udf_i.h"
+#include "udf_sb.h"
+
+static void extent_trunc(struct inode *inode, struct extent_position *epos,
+			 struct kernel_lb_addr *eloc, int8_t etype, uint32_t elen,
+			 uint32_t nelen)
+{
+	struct kernel_lb_addr neloc = {};
+	int last_block = (elen + inode->i_sb->s_blocksize - 1) >>
+		inode->i_sb->s_blocksize_bits;
+	int first_block = (nelen + inode->i_sb->s_blocksize - 1) >>
+		inode->i_sb->s_blocksize_bits;
+
+	if (nelen) {
+		if (etype == (EXT_NOT_RECORDED_ALLOCATED >> 30)) {
+			udf_free_blocks(inode->i_sb, inode, eloc, 0,
+					last_block);
+			etype = (EXT_NOT_RECORDED_NOT_ALLOCATED >> 30);
+		} else
+			neloc = *eloc;
+		nelen = (etype << 30) | nelen;
+	}
+
+	if (elen != nelen) {
+		udf_write_aext(inode, epos, &neloc, nelen, 0);
+		if (last_block - first_block > 0) {
+			if (etype == (EXT_RECORDED_ALLOCATED >> 30))
+				mark_inode_dirty(inode);
+
+			if (etype != (EXT_NOT_RECORDED_NOT_ALLOCATED >> 30))
+				udf_free_blocks(inode->i_sb, inode, eloc,
+						first_block,
+						last_block - first_block);
+		}
+	}
+}
+
+/*
+ * Truncate the last extent to match i_size. This function assumes
+ * that preallocation extent is already truncated.
+ */
+void udf_truncate_tail_extent(struct inode *inode)
+{
+	struct extent_position epos = {};
+	struct kernel_lb_addr eloc;
+	uint32_t elen, nelen;
+	uint64_t lbcount = 0;
+	int8_t etype = -1, netype;
+	int adsize;
+	struct udf_inode_info *iinfo = UDF_I(inode);
+
+	if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_IN_ICB ||
+	    inode->i_size == iinfo->i_lenExtents)
+		return;
+	/* Are we going to delete the file anyway? */
+	if (inode->i_nlink == 0)
+		return;
+
+	if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_SHORT)
+		adsize = sizeof(struct short_ad);
+	else if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_LONG)
+		adsize = sizeof(struct long_ad);
+	else
+		BUG();
+
+	/* Find the last extent in the file */
+	while ((netype = udf_next_aext(inode, &epos, &eloc, &elen, 1)) != -1) {
+		etype = netype;
+		lbcount += elen;
+		if (lbcount > inode->i_size) {
+			if (lbcount - inode->i_size >= inode->i_sb->s_blocksize)
+				udf_warn(inode->i_sb,
+					 "Too long extent after EOF in inode %u: i_size: %lld lbcount: %lld extent %u+%u\n",
+					 (unsigned)inode->i_ino,
+					 (long long)inode->i_size,
+					 (long long)lbcount,
+					 (unsigned)eloc.logicalBlockNum,
+					 (unsigned)elen);
+			nelen = elen - (lbcount - inode->i_size);
+			epos.offset -= adsize;
+			extent_trunc(inode, &epos, &eloc, etype, elen, nelen);
+			epos.offset += adsize;
+			if (udf_next_aext(inode, &epos, &eloc, &elen, 1) != -1)
+				udf_err(inode->i_sb,
+					"Extent after EOF in inode %u\n",
+					(unsigned)inode->i_ino);
+			break;
+		}
+	}
+	/* This inode entry is in-memory only and thus we don't have to mark
+	 * the inode dirty */
+	iinfo->i_lenExtents = inode->i_size;
+	brelse(epos.bh);
+}
+
+void udf_discard_prealloc(struct inode *inode)
+{
+	struct extent_position epos = { NULL, 0, {0, 0} };
+	struct kernel_lb_addr eloc;
+	uint32_t elen;
+	uint64_t lbcount = 0;
+	int8_t etype = -1, netype;
+	int adsize;
+	struct udf_inode_info *iinfo = UDF_I(inode);
+
+	if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_IN_ICB ||
+	    inode->i_size == iinfo->i_lenExtents)
+		return;
+
+	if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_SHORT)
+		adsize = sizeof(struct short_ad);
+	else if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_LONG)
+		adsize = sizeof(struct long_ad);
+	else
+		adsize = 0;
+
+	epos.block = iinfo->i_location;
+
+	/* Find the last extent in the file */
+	while ((netype = udf_next_aext(inode, &epos, &eloc, &elen, 1)) != -1) {
+		etype = netype;
+		lbcount += elen;
+	}
+	if (etype == (EXT_NOT_RECORDED_ALLOCATED >> 30)) {
+		epos.offset -= adsize;
+		lbcount -= elen;
+		extent_trunc(inode, &epos, &eloc, etype, elen, 0);
+		if (!epos.bh) {
+			iinfo->i_lenAlloc =
+				epos.offset -
+				udf_file_entry_alloc_offset(inode);
+			mark_inode_dirty(inode);
+		} else {
+			struct allocExtDesc *aed =
+				(struct allocExtDesc *)(epos.bh->b_data);
+			aed->lengthAllocDescs =
+				cpu_to_le32(epos.offset -
+					    sizeof(struct allocExtDesc));
+			if (!UDF_QUERY_FLAG(inode->i_sb, UDF_FLAG_STRICT) ||
+			    UDF_SB(inode->i_sb)->s_udfrev >= 0x0201)
+				udf_update_tag(epos.bh->b_data, epos.offset);
+			else
+				udf_update_tag(epos.bh->b_data,
+					       sizeof(struct allocExtDesc));
+			mark_buffer_dirty_inode(epos.bh, inode);
+		}
+	}
+	/* This inode entry is in-memory only and thus we don't have to mark
+	 * the inode dirty */
+	iinfo->i_lenExtents = lbcount;
+	brelse(epos.bh);
+}
+
+static void udf_update_alloc_ext_desc(struct inode *inode,
+				      struct extent_position *epos,
+				      u32 lenalloc)
+{
+	struct super_block *sb = inode->i_sb;
+	struct udf_sb_info *sbi = UDF_SB(sb);
+
+	struct allocExtDesc *aed = (struct allocExtDesc *) (epos->bh->b_data);
+	int len = sizeof(struct allocExtDesc);
+
+	aed->lengthAllocDescs =	cpu_to_le32(lenalloc);
+	if (!UDF_QUERY_FLAG(sb, UDF_FLAG_STRICT) || sbi->s_udfrev >= 0x0201)
+		len += lenalloc;
+
+	udf_update_tag(epos->bh->b_data, len);
+	mark_buffer_dirty_inode(epos->bh, inode);
+}
+
+/*
+ * Truncate extents of inode to inode->i_size. This function can be used only
+ * for making file shorter. For making file longer, udf_extend_file() has to
+ * be used.
+ */
+void udf_truncate_extents(struct inode *inode)
+{
+	struct extent_position epos;
+	struct kernel_lb_addr eloc, neloc = {};
+	uint32_t elen, nelen = 0, indirect_ext_len = 0, lenalloc;
+	int8_t etype;
+	struct super_block *sb = inode->i_sb;
+	sector_t first_block = inode->i_size >> sb->s_blocksize_bits, offset;
+	loff_t byte_offset;
+	int adsize;
+	struct udf_inode_info *iinfo = UDF_I(inode);
+
+	if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_SHORT)
+		adsize = sizeof(struct short_ad);
+	else if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_LONG)
+		adsize = sizeof(struct long_ad);
+	else
+		BUG();
+
+	etype = inode_bmap(inode, first_block, &epos, &eloc, &elen, &offset);
+	byte_offset = (offset << sb->s_blocksize_bits) +
+		(inode->i_size & (sb->s_blocksize - 1));
+	if (etype == -1) {
+		/* We should extend the file? */
+		WARN_ON(byte_offset);
+		return;
+	}
+	epos.offset -= adsize;
+	extent_trunc(inode, &epos, &eloc, etype, elen, byte_offset);
+	epos.offset += adsize;
+	if (byte_offset)
+		lenalloc = epos.offset;
+	else
+		lenalloc = epos.offset - adsize;
+
+	if (!epos.bh)
+		lenalloc -= udf_file_entry_alloc_offset(inode);
+	else
+		lenalloc -= sizeof(struct allocExtDesc);
+
+	while ((etype = udf_current_aext(inode, &epos, &eloc,
+					 &elen, 0)) != -1) {
+		if (etype == (EXT_NEXT_EXTENT_ALLOCDECS >> 30)) {
+			udf_write_aext(inode, &epos, &neloc, nelen, 0);
+			if (indirect_ext_len) {
+				/* We managed to free all extents in the
+				 * indirect extent - free it too */
+				BUG_ON(!epos.bh);
+				udf_free_blocks(sb, NULL, &epos.block,
+						0, indirect_ext_len);
+			} else if (!epos.bh) {
+				iinfo->i_lenAlloc = lenalloc;
+				mark_inode_dirty(inode);
+			} else
+				udf_update_alloc_ext_desc(inode,
+						&epos, lenalloc);
+			brelse(epos.bh);
+			epos.offset = sizeof(struct allocExtDesc);
+			epos.block = eloc;
+			epos.bh = udf_tread(sb,
+					udf_get_lb_pblock(sb, &eloc, 0));
+			if (elen)
+				indirect_ext_len =
+					(elen + sb->s_blocksize - 1) >>
+					sb->s_blocksize_bits;
+			else
+				indirect_ext_len = 1;
+		} else {
+			extent_trunc(inode, &epos, &eloc, etype, elen, 0);
+			epos.offset += adsize;
+		}
+	}
+
+	if (indirect_ext_len) {
+		BUG_ON(!epos.bh);
+		udf_free_blocks(sb, NULL, &epos.block, 0, indirect_ext_len);
+	} else if (!epos.bh) {
+		iinfo->i_lenAlloc = lenalloc;
+		mark_inode_dirty(inode);
+	} else
+		udf_update_alloc_ext_desc(inode, &epos, lenalloc);
+	iinfo->i_lenExtents = inode->i_size;
+
+	brelse(epos.bh);
+}