From: Jan Kara <jack@suse.cz>

UDF code is not really ready to handle extents larger that 1GB.  This is
the easy way to forbid creating those.

Also truncation code did not count with the case when there are no extents
in the file and we are extending the file.

Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Andrew Morton <akpm@osdl.org>
---

 fs/udf/super.c    |    2 -
 fs/udf/truncate.c |   61 ++++++++++++++++++++++++--------------------
 2 files changed, 35 insertions(+), 28 deletions(-)

diff -puN fs/udf/super.c~fix-possible-udf-deadlock-and-memory-corruption fs/udf/super.c
--- a/fs/udf/super.c~fix-possible-udf-deadlock-and-memory-corruption
+++ a/fs/udf/super.c
@@ -1663,7 +1663,7 @@ static int udf_fill_super(struct super_b
 		iput(inode);
 		goto error_out;
 	}
-	sb->s_maxbytes = MAX_LFS_FILESIZE;
+	sb->s_maxbytes = 1<<30;
 	return 0;
 
 error_out:
diff -puN fs/udf/truncate.c~fix-possible-udf-deadlock-and-memory-corruption fs/udf/truncate.c
--- a/fs/udf/truncate.c~fix-possible-udf-deadlock-and-memory-corruption
+++ a/fs/udf/truncate.c
@@ -239,37 +239,44 @@ void udf_truncate_extents(struct inode *
 	{
 		if (offset)
 		{
-			extoffset -= adsize;
-			etype = udf_next_aext(inode, &bloc, &extoffset, &eloc, &elen, &bh, 1);
-			if (etype == (EXT_NOT_RECORDED_NOT_ALLOCATED >> 30))
-			{
-				extoffset -= adsize;
-				elen = EXT_NOT_RECORDED_NOT_ALLOCATED | (elen + offset);
-				udf_write_aext(inode, bloc, &extoffset, eloc, elen, bh, 0);
-			}
-			else if (etype == (EXT_NOT_RECORDED_ALLOCATED >> 30))
-			{
-				kernel_lb_addr neloc = { 0, 0 };
+			/*
+			 *  OK, there is not extent covering inode->i_size and
+			 *  no extent above inode->i_size => truncate is
+			 *  extending the file by 'offset'.
+			 */
+			if ((!bh && extoffset == udf_file_entry_alloc_offset(inode)) ||
+			    (bh && extoffset == sizeof(struct allocExtDesc))) {
+				/* File has no extents at all! */
+				memset(&eloc, 0x00, sizeof(kernel_lb_addr));
+				elen = EXT_NOT_RECORDED_NOT_ALLOCATED | offset;
+				udf_add_aext(inode, &bloc, &extoffset, eloc, elen, &bh, 1);
+			} else {
 				extoffset -= adsize;
-				nelen = EXT_NOT_RECORDED_NOT_ALLOCATED |
-					((elen + offset + inode->i_sb->s_blocksize - 1) &
-					~(inode->i_sb->s_blocksize - 1));
-				udf_write_aext(inode, bloc, &extoffset, neloc, nelen, bh, 1);
-				udf_add_aext(inode, &bloc, &extoffset, eloc, (etype << 30) | elen, &bh, 1);
-			}
-			else
-			{
-				if (elen & (inode->i_sb->s_blocksize - 1))
-				{
+				etype = udf_next_aext(inode, &bloc, &extoffset, &eloc, &elen, &bh, 1);
+				if (etype == (EXT_NOT_RECORDED_NOT_ALLOCATED >> 30)) {
+					extoffset -= adsize;
+					elen = EXT_NOT_RECORDED_NOT_ALLOCATED | (elen + offset);
+					udf_write_aext(inode, bloc, &extoffset, eloc, elen, bh, 0);
+				} else if (etype == (EXT_NOT_RECORDED_ALLOCATED >> 30)) {
+					kernel_lb_addr neloc = { 0, 0 };
 					extoffset -= adsize;
-					elen = EXT_RECORDED_ALLOCATED |
-						((elen + inode->i_sb->s_blocksize - 1) &
+					nelen = EXT_NOT_RECORDED_NOT_ALLOCATED |
+						((elen + offset + inode->i_sb->s_blocksize - 1) &
 						~(inode->i_sb->s_blocksize - 1));
-					udf_write_aext(inode, bloc, &extoffset, eloc, elen, bh, 1);
+					udf_write_aext(inode, bloc, &extoffset, neloc, nelen, bh, 1);
+					udf_add_aext(inode, &bloc, &extoffset, eloc, (etype << 30) | elen, &bh, 1);
+				} else {
+					if (elen & (inode->i_sb->s_blocksize - 1)) {
+						extoffset -= adsize;
+						elen = EXT_RECORDED_ALLOCATED |
+							((elen + inode->i_sb->s_blocksize - 1) &
+							~(inode->i_sb->s_blocksize - 1));
+						udf_write_aext(inode, bloc, &extoffset, eloc, elen, bh, 1);
+					}
+					memset(&eloc, 0x00, sizeof(kernel_lb_addr));
+					elen = EXT_NOT_RECORDED_NOT_ALLOCATED | offset;
+					udf_add_aext(inode, &bloc, &extoffset, eloc, elen, &bh, 1);
 				}
-				memset(&eloc, 0x00, sizeof(kernel_lb_addr));
-				elen = EXT_NOT_RECORDED_NOT_ALLOCATED | offset;
-				udf_add_aext(inode, &bloc, &extoffset, eloc, elen, &bh, 1);
 			}
 		}
 	}
_