From 102a0743326a03cd1a1202ceda21e175b7d3575c Mon Sep 17 00:00:00 2001
From: hc <hc@nodka.com>
Date: Tue, 20 Feb 2024 01:20:52 +0000
Subject: [PATCH] add new system file

---
 kernel/fs/udf/inode.c |  195 ++++++++++++++++++++++++------------------------
 1 files changed, 99 insertions(+), 96 deletions(-)

diff --git a/kernel/fs/udf/inode.c b/kernel/fs/udf/inode.c
index d32b836..499a273 100644
--- a/kernel/fs/udf/inode.c
+++ b/kernel/fs/udf/inode.c
@@ -57,15 +57,15 @@
 static int udf_sync_inode(struct inode *inode);
 static int udf_alloc_i_data(struct inode *inode, size_t size);
 static sector_t inode_getblk(struct inode *, sector_t, int *, int *);
-static int8_t udf_insert_aext(struct inode *, struct extent_position,
-			      struct kernel_lb_addr, uint32_t);
+static int udf_insert_aext(struct inode *, struct extent_position,
+			   struct kernel_lb_addr, uint32_t);
 static void udf_split_extents(struct inode *, int *, int, udf_pblk_t,
 			      struct kernel_long_ad *, int *);
 static void udf_prealloc_extents(struct inode *, int, int,
 				 struct kernel_long_ad *, int *);
 static void udf_merge_extents(struct inode *, struct kernel_long_ad *, int *);
-static void udf_update_extents(struct inode *, struct kernel_long_ad *, int,
-			       int, struct extent_position *);
+static int udf_update_extents(struct inode *, struct kernel_long_ad *, int,
+			      int, struct extent_position *);
 static int udf_get_block(struct inode *, sector_t, struct buffer_head *, int);
 
 static void __udf_clear_extent_cache(struct inode *inode)
@@ -438,6 +438,12 @@
 		iinfo->i_next_alloc_goal++;
 	}
 
+	/*
+	 * Block beyond EOF and prealloc extents? Just discard preallocation
+	 * as it is not useful and complicates things.
+	 */
+	if (((loff_t)block) << inode->i_blkbits >= iinfo->i_lenExtents)
+		udf_discard_prealloc(inode);
 	udf_clear_extent_cache(inode);
 	phys = inode_getblk(inode, block, &err, &new);
 	if (!phys)
@@ -487,8 +493,6 @@
 	uint32_t add;
 	int count = 0, fake = !(last_ext->extLength & UDF_EXTENT_LENGTH_MASK);
 	struct super_block *sb = inode->i_sb;
-	struct kernel_lb_addr prealloc_loc = {};
-	uint32_t prealloc_len = 0;
 	struct udf_inode_info *iinfo;
 	int err;
 
@@ -509,19 +513,6 @@
 			~(sb->s_blocksize - 1);
 	}
 
-	/* Last extent are just preallocated blocks? */
-	if ((last_ext->extLength & UDF_EXTENT_FLAG_MASK) ==
-						EXT_NOT_RECORDED_ALLOCATED) {
-		/* Save the extent so that we can reattach it to the end */
-		prealloc_loc = last_ext->extLocation;
-		prealloc_len = last_ext->extLength;
-		/* Mark the extent as a hole */
-		last_ext->extLength = EXT_NOT_RECORDED_NOT_ALLOCATED |
-			(last_ext->extLength & UDF_EXTENT_LENGTH_MASK);
-		last_ext->extLocation.logicalBlockNum = 0;
-		last_ext->extLocation.partitionReferenceNum = 0;
-	}
-
 	/* Can we merge with the previous extent? */
 	if ((last_ext->extLength & UDF_EXTENT_FLAG_MASK) ==
 					EXT_NOT_RECORDED_NOT_ALLOCATED) {
@@ -534,8 +525,10 @@
 	}
 
 	if (fake) {
-		udf_add_aext(inode, last_pos, &last_ext->extLocation,
-			     last_ext->extLength, 1);
+		err = udf_add_aext(inode, last_pos, &last_ext->extLocation,
+				   last_ext->extLength, 1);
+		if (err < 0)
+			goto out_err;
 		count++;
 	} else {
 		struct kernel_lb_addr tmploc;
@@ -549,7 +542,7 @@
 		 * more extents, we may need to enter possible following
 		 * empty indirect extent.
 		 */
-		if (new_block_bytes || prealloc_len)
+		if (new_block_bytes)
 			udf_next_aext(inode, last_pos, &tmploc, &tmplen, 0);
 	}
 
@@ -569,7 +562,7 @@
 		err = udf_add_aext(inode, last_pos, &last_ext->extLocation,
 				   last_ext->extLength, 1);
 		if (err)
-			return err;
+			goto out_err;
 		count++;
 	}
 	if (new_block_bytes) {
@@ -578,22 +571,11 @@
 		err = udf_add_aext(inode, last_pos, &last_ext->extLocation,
 				   last_ext->extLength, 1);
 		if (err)
-			return err;
+			goto out_err;
 		count++;
 	}
 
 out:
-	/* Do we have some preallocated blocks saved? */
-	if (prealloc_len) {
-		err = udf_add_aext(inode, last_pos, &prealloc_loc,
-				   prealloc_len, 1);
-		if (err)
-			return err;
-		last_ext->extLocation = prealloc_loc;
-		last_ext->extLength = prealloc_len;
-		count++;
-	}
-
 	/* last_pos should point to the last written extent... */
 	if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_SHORT)
 		last_pos->offset -= sizeof(struct short_ad);
@@ -603,19 +585,28 @@
 		return -EIO;
 
 	return count;
+out_err:
+	/* Remove extents we've created so far */
+	udf_clear_extent_cache(inode);
+	udf_truncate_extents(inode);
+	return err;
 }
 
 /* Extend the final block of the file to final_block_len bytes */
 static void udf_do_extend_final_block(struct inode *inode,
 				      struct extent_position *last_pos,
 				      struct kernel_long_ad *last_ext,
-				      uint32_t final_block_len)
+				      uint32_t new_elen)
 {
-	struct super_block *sb = inode->i_sb;
 	uint32_t added_bytes;
 
-	added_bytes = final_block_len -
-		      (last_ext->extLength & (sb->s_blocksize - 1));
+	/*
+	 * Extent already large enough? It may be already rounded up to block
+	 * size...
+	 */
+	if (new_elen <= (last_ext->extLength & UDF_EXTENT_LENGTH_MASK))
+		return;
+	added_bytes = new_elen - (last_ext->extLength & UDF_EXTENT_LENGTH_MASK);
 	last_ext->extLength += added_bytes;
 	UDF_I(inode)->i_lenExtents += added_bytes;
 
@@ -632,12 +623,12 @@
 	int8_t etype;
 	struct super_block *sb = inode->i_sb;
 	sector_t first_block = newsize >> sb->s_blocksize_bits, offset;
-	unsigned long partial_final_block;
+	loff_t new_elen;
 	int adsize;
 	struct udf_inode_info *iinfo = UDF_I(inode);
 	struct kernel_long_ad extent;
 	int err = 0;
-	int within_final_block;
+	bool within_last_ext;
 
 	if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_SHORT)
 		adsize = sizeof(struct short_ad);
@@ -646,8 +637,17 @@
 	else
 		BUG();
 
+	/*
+	 * When creating hole in file, just don't bother with preserving
+	 * preallocation. It likely won't be very useful anyway.
+	 */
+	udf_discard_prealloc(inode);
+
 	etype = inode_bmap(inode, first_block, &epos, &eloc, &elen, &offset);
-	within_final_block = (etype != -1);
+	within_last_ext = (etype != -1);
+	/* We don't expect extents past EOF... */
+	WARN_ON_ONCE(within_last_ext &&
+		     elen > ((loff_t)offset + 1) << inode->i_blkbits);
 
 	if ((!epos.bh && epos.offset == udf_file_entry_alloc_offset(inode)) ||
 	    (epos.bh && epos.offset == sizeof(struct allocExtDesc))) {
@@ -663,19 +663,17 @@
 		extent.extLength |= etype << 30;
 	}
 
-	partial_final_block = newsize & (sb->s_blocksize - 1);
+	new_elen = ((loff_t)offset << inode->i_blkbits) |
+					(newsize & (sb->s_blocksize - 1));
 
 	/* File has extent covering the new size (could happen when extending
 	 * inside a block)?
 	 */
-	if (within_final_block) {
+	if (within_last_ext) {
 		/* Extending file within the last file block */
-		udf_do_extend_final_block(inode, &epos, &extent,
-					  partial_final_block);
+		udf_do_extend_final_block(inode, &epos, &extent, new_elen);
 	} else {
-		loff_t add = ((loff_t)offset << sb->s_blocksize_bits) |
-			     partial_final_block;
-		err = udf_do_extend_file(inode, &epos, &extent, add);
+		err = udf_do_extend_file(inode, &epos, &extent, new_elen);
 	}
 
 	if (err < 0)
@@ -697,7 +695,7 @@
 	struct kernel_lb_addr eloc, tmpeloc;
 	int c = 1;
 	loff_t lbcount = 0, b_off = 0;
-	udf_pblk_t newblocknum, newblock;
+	udf_pblk_t newblocknum, newblock = 0;
 	sector_t offset = 0;
 	int8_t etype;
 	struct udf_inode_info *iinfo = UDF_I(inode);
@@ -776,10 +774,11 @@
 		goto out_free;
 	}
 
-	/* Are we beyond EOF? */
+	/* Are we beyond EOF and preallocated extent? */
 	if (etype == -1) {
 		int ret;
 		loff_t hole_len;
+
 		isBeyondEOF = true;
 		if (count) {
 			if (c)
@@ -799,25 +798,22 @@
 		ret = udf_do_extend_file(inode, &prev_epos, laarr, hole_len);
 		if (ret < 0) {
 			*err = ret;
-			newblock = 0;
 			goto out_free;
 		}
 		c = 0;
 		offset = 0;
 		count += ret;
-		/* We are not covered by a preallocated extent? */
-		if ((laarr[0].extLength & UDF_EXTENT_FLAG_MASK) !=
-						EXT_NOT_RECORDED_ALLOCATED) {
-			/* Is there any real extent? - otherwise we overwrite
-			 * the fake one... */
-			if (count)
-				c = !c;
-			laarr[c].extLength = EXT_NOT_RECORDED_NOT_ALLOCATED |
-				inode->i_sb->s_blocksize;
-			memset(&laarr[c].extLocation, 0x00,
-				sizeof(struct kernel_lb_addr));
-			count++;
-		}
+		/*
+		 * Is there any real extent? - otherwise we overwrite the fake
+		 * one...
+		 */
+		if (count)
+			c = !c;
+		laarr[c].extLength = EXT_NOT_RECORDED_NOT_ALLOCATED |
+			inode->i_sb->s_blocksize;
+		memset(&laarr[c].extLocation, 0x00,
+			sizeof(struct kernel_lb_addr));
+		count++;
 		endnum = c + 1;
 		lastblock = 1;
 	} else {
@@ -864,7 +860,6 @@
 				goal, err);
 		if (!newblocknum) {
 			*err = -ENOSPC;
-			newblock = 0;
 			goto out_free;
 		}
 		if (isBeyondEOF)
@@ -890,7 +885,9 @@
 	/* write back the new extents, inserting new extents if the new number
 	 * of extents is greater than the old number, and deleting extents if
 	 * the new number of extents is less than the old number */
-	udf_update_extents(inode, laarr, startnum, endnum, &prev_epos);
+	*err = udf_update_extents(inode, laarr, startnum, endnum, &prev_epos);
+	if (*err < 0)
+		goto out_free;
 
 	newblock = udf_get_pblock(inode->i_sb, newblocknum,
 				iinfo->i_location.partitionReferenceNum, 0);
@@ -1094,23 +1091,8 @@
 			blocksize - 1) >> blocksize_bits)))) {
 
 			if (((li->extLength & UDF_EXTENT_LENGTH_MASK) +
-				(lip1->extLength & UDF_EXTENT_LENGTH_MASK) +
-				blocksize - 1) & ~UDF_EXTENT_LENGTH_MASK) {
-				lip1->extLength = (lip1->extLength -
-						  (li->extLength &
-						   UDF_EXTENT_LENGTH_MASK) +
-						   UDF_EXTENT_LENGTH_MASK) &
-							~(blocksize - 1);
-				li->extLength = (li->extLength &
-						 UDF_EXTENT_FLAG_MASK) +
-						(UDF_EXTENT_LENGTH_MASK + 1) -
-						blocksize;
-				lip1->extLocation.logicalBlockNum =
-					li->extLocation.logicalBlockNum +
-					((li->extLength &
-						UDF_EXTENT_LENGTH_MASK) >>
-						blocksize_bits);
-			} else {
+			     (lip1->extLength & UDF_EXTENT_LENGTH_MASK) +
+			     blocksize - 1) <= UDF_EXTENT_LENGTH_MASK) {
 				li->extLength = lip1->extLength +
 					(((li->extLength &
 						UDF_EXTENT_LENGTH_MASK) +
@@ -1173,21 +1155,30 @@
 	}
 }
 
-static void udf_update_extents(struct inode *inode, struct kernel_long_ad *laarr,
-			       int startnum, int endnum,
-			       struct extent_position *epos)
+static int udf_update_extents(struct inode *inode, struct kernel_long_ad *laarr,
+			      int startnum, int endnum,
+			      struct extent_position *epos)
 {
 	int start = 0, i;
 	struct kernel_lb_addr tmploc;
 	uint32_t tmplen;
+	int err;
 
 	if (startnum > endnum) {
 		for (i = 0; i < (startnum - endnum); i++)
 			udf_delete_aext(inode, *epos);
 	} else if (startnum < endnum) {
 		for (i = 0; i < (endnum - startnum); i++) {
-			udf_insert_aext(inode, *epos, laarr[i].extLocation,
-					laarr[i].extLength);
+			err = udf_insert_aext(inode, *epos,
+					      laarr[i].extLocation,
+					      laarr[i].extLength);
+			/*
+			 * If we fail here, we are likely corrupting the extent
+			 * list and leaking blocks. At least stop early to
+			 * limit the damage.
+			 */
+			if (err < 0)
+				return err;
 			udf_next_aext(inode, epos, &laarr[i].extLocation,
 				      &laarr[i].extLength, 1);
 			start++;
@@ -1199,6 +1190,7 @@
 		udf_write_aext(inode, epos, &laarr[i].extLocation,
 			       laarr[i].extLength, 1);
 	}
+	return 0;
 }
 
 struct buffer_head *udf_bread(struct inode *inode, udf_pblk_t block,
@@ -1401,6 +1393,7 @@
 		ret = -EIO;
 		goto out;
 	}
+	iinfo->i_hidden = hidden_inode;
 	iinfo->i_unique = 0;
 	iinfo->i_lenEAttr = 0;
 	iinfo->i_lenExtents = 0;
@@ -1736,8 +1729,12 @@
 
 	if (S_ISDIR(inode->i_mode) && inode->i_nlink > 0)
 		fe->fileLinkCount = cpu_to_le16(inode->i_nlink - 1);
-	else
-		fe->fileLinkCount = cpu_to_le16(inode->i_nlink);
+	else {
+		if (iinfo->i_hidden)
+			fe->fileLinkCount = cpu_to_le16(0);
+		else
+			fe->fileLinkCount = cpu_to_le16(inode->i_nlink);
+	}
 
 	fe->informationLength = cpu_to_le64(inode->i_size);
 
@@ -1908,8 +1905,13 @@
 	if (!inode)
 		return ERR_PTR(-ENOMEM);
 
-	if (!(inode->i_state & I_NEW))
+	if (!(inode->i_state & I_NEW)) {
+		if (UDF_I(inode)->i_hidden != hidden_inode) {
+			iput(inode);
+			return ERR_PTR(-EFSCORRUPTED);
+		}
 		return inode;
+	}
 
 	memcpy(&UDF_I(inode)->i_location, ino, sizeof(struct kernel_lb_addr));
 	err = udf_read_inode(inode, hidden_inode);
@@ -2223,12 +2225,13 @@
 	return etype;
 }
 
-static int8_t udf_insert_aext(struct inode *inode, struct extent_position epos,
-			      struct kernel_lb_addr neloc, uint32_t nelen)
+static int udf_insert_aext(struct inode *inode, struct extent_position epos,
+			   struct kernel_lb_addr neloc, uint32_t nelen)
 {
 	struct kernel_lb_addr oeloc;
 	uint32_t oelen;
 	int8_t etype;
+	int err;
 
 	if (epos.bh)
 		get_bh(epos.bh);
@@ -2238,10 +2241,10 @@
 		neloc = oeloc;
 		nelen = (etype << 30) | oelen;
 	}
-	udf_add_aext(inode, &epos, &neloc, nelen, 1);
+	err = udf_add_aext(inode, &epos, &neloc, nelen, 1);
 	brelse(epos.bh);
 
-	return (nelen >> 30);
+	return err;
 }
 
 int8_t udf_delete_aext(struct inode *inode, struct extent_position epos)

--
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