From dc7b8dad997fdd32494d7c63abe54a8f051fbc5a Mon Sep 17 00:00:00 2001
From: "Darrick J. Wong" <darrick.wong@oracle.com>
Date: Tue, 2 Dec 2014 22:57:14 -0500
Subject: [PATCH] libext2fs: file IO routines should handle uninit blocks

The file IO routines do not handle uninit blocks at all.  The read
method should check for the uninit flag and return a buffer of zeroes,
and the write routine should convert unwritten extents.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
---
 lib/ext2fs/fileio.c         |  24 +++++++++++++++++++++--
 tests/f_uninit_cat/expect   | Bin 0 -> 3623 bytes
 tests/f_uninit_cat/image.gz | Bin 0 -> 1553 bytes
 tests/f_uninit_cat/name     |   1 +
 tests/f_uninit_cat/script   |  37 ++++++++++++++++++++++++++++++++++++
 5 files changed, 60 insertions(+), 2 deletions(-)
 create mode 100644 tests/f_uninit_cat/expect
 create mode 100644 tests/f_uninit_cat/image.gz
 create mode 100644 tests/f_uninit_cat/name
 create mode 100755 tests/f_uninit_cat/script

diff --git a/lib/ext2fs/fileio.c b/lib/ext2fs/fileio.c
index 1d5032a5b..d0a05d67c 100644
--- a/lib/ext2fs/fileio.c
+++ b/lib/ext2fs/fileio.c
@@ -123,6 +123,8 @@ errcode_t ext2fs_file_flush(ext2_file_t file)
 {
 	errcode_t	retval;
 	ext2_filsys fs;
+	int		ret_flags;
+	blk64_t		dontcare;
 
 	EXT2_CHECK_MAGIC(file, EXT2_ET_MAGIC_EXT2_FILE);
 	fs = file->fs;
@@ -131,6 +133,22 @@ errcode_t ext2fs_file_flush(ext2_file_t file)
 	    !(file->flags & EXT2_FILE_BUF_DIRTY))
 		return 0;
 
+	/* Is this an uninit block? */
+	if (file->physblock && file->inode.i_flags & EXT4_EXTENTS_FL) {
+		retval = ext2fs_bmap2(fs, file->ino, &file->inode, BMAP_BUFFER,
+				      0, file->blockno, &ret_flags, &dontcare);
+		if (retval)
+			return retval;
+		if (ret_flags & BMAP_RET_UNINIT) {
+			retval = ext2fs_bmap2(fs, file->ino, &file->inode,
+					      BMAP_BUFFER, BMAP_SET,
+					      file->blockno, 0,
+					      &file->physblock);
+			if (retval)
+				return retval;
+		}
+	}
+
 	/*
 	 * OK, the physical block hasn't been allocated yet.
 	 * Allocate it.
@@ -185,15 +203,17 @@ static errcode_t load_buffer(ext2_file_t file, int dontfill)
 {
 	ext2_filsys	fs = file->fs;
 	errcode_t	retval;
+	int		ret_flags;
 
 	if (!(file->flags & EXT2_FILE_BUF_VALID)) {
 		retval = ext2fs_bmap2(fs, file->ino, &file->inode,
-				     BMAP_BUFFER, 0, file->blockno, 0,
+				     BMAP_BUFFER, 0, file->blockno, &ret_flags,
 				     &file->physblock);
 		if (retval)
 			return retval;
 		if (!dontfill) {
-			if (file->physblock) {
+			if (file->physblock &&
+			    !(ret_flags & BMAP_RET_UNINIT)) {
 				retval = io_channel_read_blk64(fs->io,
 							       file->physblock,
 							       1, file->buf);
diff --git a/tests/f_uninit_cat/expect b/tests/f_uninit_cat/expect
new file mode 100644
index 0000000000000000000000000000000000000000..0c0a5cf84cc58483ca33e257259607e4ca54ebbe
GIT binary patch
literal 3623
zc-rlhziz@X5XL*_DQ>CMN~Li^K!vrU69Y@<$~c#BBG{GBMx;+)=MNF8`Udzn<Z|}+
z`SWGSPBKHbhW7)iBk3AQn-cj2_Ki`;P^B(`=?6L4b<+GsT9QTOjBSCP^~!mRgJ}M*
zNExleE1k);gRZ#IS**~aRv2_%yD@HYqo}R%-@yKKlHoMcm9Z!3$mql&yRV8G<d)Zv
z<>|73zJ(|8Djq=_JqziMYHvJ0zd*4_Gm#hLkjdskF3cdEXCMZVl(_eG#h|1EuStjP
z?!4>z8t?+COtyH&1~%GR3RweNQ<IX-(CiK^_uUqC?GEtK$eI%nDTuI}r2z9@Ctx<#
zz~XJ_LhZ@mv%kXR%O_tp`m$cX8hxv)Z*t5hM?O08?y($mm*P*-G-vk#!k`b4NaSw0
QL?V&9CH?^;k^3e21-(dqivR!s

literal 0
Hc-jL100001

diff --git a/tests/f_uninit_cat/image.gz b/tests/f_uninit_cat/image.gz
new file mode 100644
index 0000000000000000000000000000000000000000..d2ae66cb35f93dd4022e85f8667365487a7b24ea
GIT binary patch
literal 1553
zc-oWi=3wBo77AfvetUOgws4>X!-w+e5!ulJUCtMqn*6x7X0!`+M-&JY2D}M!S)+8+
zDVJ6IMapY?1&f!@9@sy4qUHCltf(-cFi@sM<Z<;*mRk{C3zur%doRAP`s7{J>E%1$
zf6YFjs>qO9YUaC2aZcCS-(DQb8_$NVE7;Mo<=)q*|3~ghM6S5L{?7@i*S^PYuMLg<
z{yO)bMDN+#HZAQNWmni(e$ISz=k4?0&B2S~=hf!a%c;LRqnoqOeE0R(Td}i${(5!v
zN9*zV=lkXUet4HAR(*B4`0223$*Xyed2c)RXUFctq3v?k4*osNhJB`=>Q$cfF5YY)
zq&Ig<I|BqHJYRiXzO>c;>t5Mgf0ATh%=q$g`@RWJoj2;Pd;ar6z(>h_e;2CHpSyp1
zK~2@ae|Oey(P??=HSMlJ&Y}8++jalfhj#s8_ga)C-tdS0iM_&q#-IEr>K*<uf0Cc@
zA1uVcut9k1xj*G<CR6-R{q_2++YoEG%ju)G)m_7H5^{_T$Y6o8TJ~SzwHm?u_xHCS
zJ9&QPedDtl(?X>7x6e7(a_-TV=jq#CWna3q=brA3e+fPL>eH78Z;4}fSKc5iHvLh`
zj;O!of6gD;=WF-vAa7s&+xqrBS{rQdE%}vRvG$ifKl9mN>T3f3e=$wgel_3k+5gi^
z7b&lNH#^rY`_JpB(Ep)f*Xz3#ugoe<=(^l%8+JxM`}VQ-*^}F^z5ajn^!oYBJWLa+
u<km(BAiGy%yRt*3ErZu-4vwc!?G+eC!6+C7LlKxg(!a2sC7gjlfB^sn{wW~<

literal 0
Hc-jL100001

diff --git a/tests/f_uninit_cat/name b/tests/f_uninit_cat/name
new file mode 100644
index 000000000..f6b5674df
--- /dev/null
+++ b/tests/f_uninit_cat/name
@@ -0,0 +1 @@
+cat a file with uninit blocks
diff --git a/tests/f_uninit_cat/script b/tests/f_uninit_cat/script
new file mode 100755
index 000000000..1655bb071
--- /dev/null
+++ b/tests/f_uninit_cat/script
@@ -0,0 +1,37 @@
+#!/bin/bash
+
+if test -x $DEBUGFS_EXE; then
+FSCK_OPT=-fy
+IMAGE=$test_dir/image.gz
+
+gzip -d < $IMAGE > $TMPFILE
+#e2label $TMPFILE test_filesys
+
+# Run fsck to fix things?
+EXP=$test_dir/expect
+OUT=$test_name.log
+rm -rf $test_name.failed $test_name.ok
+
+$FSCK $FSCK_OPT -N test_filesys $TMPFILE 2>&1 | sed -f $cmd_dir/filter.sed > $OUT
+echo "Exit status is $?" >> $OUT
+
+echo "debugfs cat uninit file" >> $OUT
+echo "ex /a" > $TMPFILE.cmd
+echo "cat /a" >> $TMPFILE.cmd
+$DEBUGFS_EXE -w -f $TMPFILE.cmd $TMPFILE >> $OUT.new 2>&1
+echo >> $OUT.new
+sed -f $cmd_dir/filter.sed < $OUT.new >> $OUT
+rm -rf $OUT.new $TMPFILE
+
+# Figure out what happened
+if cmp -s $EXP $OUT; then
+	echo "$test_name: $test_description: ok"
+	touch $test_name.ok
+else
+	echo "$test_name: $test_description: failed"
+	diff -u $EXP $OUT >> $test_name.failed
+fi
+unset EXP OUT FSCK_OPT IMAGE
+else #if test -a -x $DEBUGFS_EXE; then
+        echo "$test_name: $test_description: skipped"
+fi 
-- 
2.47.2