linux-stable.git/fs/ext4/inode.c, branch linux-4.1.y

ext4: bugfix for mmaped pages in mpage_release_unused_pages()

2018-05-23T01:36:35+00:00

[ Upstream commit 4e800c0359d9a53e6bf0ab216954971b2515247f ]

Pages clear buffers after ext4 delayed block allocation failed,
However, it does not clean its pte_dirty flag.
if the pages unmap ,in cording to the pte_dirty ,
unmap_page_range may try to call __set_page_dirty,

which may lead to the bugon at
mpage_prepare_extent_to_map:head = page_buffers(page);.

This patch just call clear_page_dirty_for_io to clean pte_dirty
at mpage_release_unused_pages for pages mmaped.

Steps to reproduce the bug:

（1） mmap a file in ext4
	addr = (char *)mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_SHARED,
	       	            fd, 0);
	memset(addr, 'i', 4096);

（2） return EIO at

	ext4_writepages->mpage_map_and_submit_extent->mpage_map_one_extent

which causes this log message to be print:

                ext4_msg(sb, KERN_CRIT,
                        "Delayed block allocation failed for "
                        "inode %lu at logical offset %llu with"
                        " max blocks %u with error %d",
                        inode->i_ino,
                        (unsigned long long)map->m_lblk,
                        (unsigned)map->m_len, -err);

(3）Unmap the addr cause warning at

	__set_page_dirty:WARN_ON_ONCE(warn && !PageUptodate(page));

(4) wait for a minute,then bugon happen.

Cc: stable@vger.kernel.org
Signed-off-by: wangguang 
Signed-off-by: Theodore Ts'o 
Signed-off-by: Sasha Levin

ext4: don't BUG when truncating encrypted inodes on the orphan list

2018-01-17T17:27:24+00:00

[ Upstream commit 0d06863f903ac5f4f6efb0273079d27de3e53a28 ]

Fix a BUG when the kernel tries to mount a file system constructed as
follows:

echo foo > foo.txt
mke2fs -Fq -t ext4 -O encrypt foo.img 100
debugfs -w foo.img << EOF
write foo.txt a
set_inode_field a i_flags 0x80800
set_super_value s_last_orphan 12
quit
EOF

root@kvm-xfstests:~# mount -o loop foo.img /mnt
[  160.238770] ------------[ cut here ]------------
[  160.240106] kernel BUG at /usr/projects/linux/ext4/fs/ext4/inode.c:3874!
[  160.240106] invalid opcode: 0000 [#1] SMP
[  160.240106] Modules linked in:
[  160.240106] CPU: 0 PID: 2547 Comm: mount Tainted: G        W       4.10.0-rc3-00034-gcdd33b941b67 #227
[  160.240106] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.1-1 04/01/2014
[  160.240106] task: f4518000 task.stack: f47b6000
[  160.240106] EIP: ext4_block_zero_page_range+0x1a7/0x2b4
[  160.240106] EFLAGS: 00010246 CPU: 0
[  160.240106] EAX: 00000001 EBX: f7be4b50 ECX: f47b7dc0 EDX: 00000007
[  160.240106] ESI: f43b05a8 EDI: f43babec EBP: f47b7dd0 ESP: f47b7dac
[  160.240106]  DS: 007b ES: 007b FS: 00d8 GS: 0033 SS: 0068
[  160.240106] CR0: 80050033 CR2: bfd85b08 CR3: 34a00680 CR4: 000006f0
[  160.240106] Call Trace:
[  160.240106]  ext4_truncate+0x1e9/0x3e5
[  160.240106]  ext4_fill_super+0x286f/0x2b1e
[  160.240106]  ? set_blocksize+0x2e/0x7e
[  160.240106]  mount_bdev+0x114/0x15f
[  160.240106]  ext4_mount+0x15/0x17
[  160.240106]  ? ext4_calculate_overhead+0x39d/0x39d
[  160.240106]  mount_fs+0x58/0x115
[  160.240106]  vfs_kern_mount+0x4b/0xae
[  160.240106]  do_mount+0x671/0x8c3
[  160.240106]  ? _copy_from_user+0x70/0x83
[  160.240106]  ? strndup_user+0x31/0x46
[  160.240106]  SyS_mount+0x57/0x7b
[  160.240106]  do_int80_syscall_32+0x4f/0x61
[  160.240106]  entry_INT80_32+0x2f/0x2f
[  160.240106] EIP: 0xb76b919e
[  160.240106] EFLAGS: 00000246 CPU: 0
[  160.240106] EAX: ffffffda EBX: 08053838 ECX: 08052188 EDX: 080537e8
[  160.240106] ESI: c0ed0000 EDI: 00000000 EBP: 080537e8 ESP: bfa13660
[  160.240106]  DS: 007b ES: 007b FS: 0000 GS: 0033 SS: 007b
[  160.240106] Code: 59 8b 00 a8 01 0f 84 09 01 00 00 8b 07 66 25 00 f0 66 3d 00 80 75 61 89 f8 e8 3e e2 ff ff 84 c0 74 56 83 bf 48 02 00 00 00 75 02 <0f> 0b 81 7d e8 00 10 00 00 74 02 0f 0b 8b 43 04 8b 53 08 31 c9
[  160.240106] EIP: ext4_block_zero_page_range+0x1a7/0x2b4 SS:ESP: 0068:f47b7dac
[  160.317241] ---[ end trace d6a773a375c810a5 ]---

The problem is that when the kernel tries to truncate an inode in
ext4_truncate(), it tries to clear any on-disk data beyond i_size.
Without the encryption key, it can't do that, and so it triggers a
BUG.

E2fsck does *not* provide this service, and in practice most file
systems have their orphan list processed by e2fsck, so to avoid
crashing, this patch skips this step if we don't have access to the
encryption key (which is the case when processing the orphan list; in
all other cases, we will have the encryption key, or the kernel
wouldn't have allowed the file to be opened).

An open question is whether the fact that e2fsck isn't clearing the
bytes beyond i_size causing problems --- and if we've lived with it
not doing it for so long, can we drop this from the kernel replay of
the orphan list in all cases (not just when we don't have the key for
encrypted inodes).

Addresses-Google-Bug: #35209576

Signed-off-by: Theodore Ts'o 
Signed-off-by: Sasha Levin

ext4: fix data exposure after a crash

2017-12-07T02:20:08+00:00

[ Upstream commit 06bd3c36a733ac27962fea7d6f47168841376824 ]

Huang has reported that in his powerfail testing he is seeing stale
block contents in some of recently allocated blocks although he mounts
ext4 in data=ordered mode. After some investigation I have found out
that indeed when delayed allocation is used, we don't add inode to
transaction's list of inodes needing flushing before commit. Originally
we were doing that but commit f3b59291a69d removed the logic with a
flawed argument that it is not needed.

The problem is that although for delayed allocated blocks we write their
contents immediately after allocating them, there is no guarantee that
the IO scheduler or device doesn't reorder things and thus transaction
allocating blocks and attaching them to inode can reach stable storage
before actual block contents. Actually whenever we attach freshly
allocated blocks to inode using a written extent, we should add inode to
transaction's ordered inode list to make sure we properly wait for block
contents to be written before committing the transaction. So that is
what we do in this patch. This also handles other cases where stale data
exposure was possible - like filling hole via mmap in
data=ordered,nodelalloc mode.

The only exception to the above rule are extending direct IO writes where
blkdev_direct_IO() waits for IO to complete before increasing i_size and
thus stale data exposure is not possible. For now we don't complicate
the code with optimizing this special case since the overhead is pretty
low. In case this is observed to be a performance problem we can always
handle it using a special flag to ext4_map_blocks().

CC: stable@vger.kernel.org
Fixes: f3b59291a69d0b734be1fc8be489fef2dd846d3d
Reported-by: "HUANG Weller (CM/ESW12-CN)" 
Tested-by: "HUANG Weller (CM/ESW12-CN)" 
Signed-off-by: Jan Kara 
Signed-off-by: Theodore Ts'o 
Signed-off-by: Sasha Levin

ext4: fix data corruption for mmap writes

2017-11-06T04:54:22+00:00

[ Upstream commit a056bdaae7a181f7dcc876cfab2f94538e508709 ]

mpage_submit_page() can race with another process growing i_size and
writing data via mmap to the written-back page. As mpage_submit_page()
samples i_size too early, it may happen that ext4_bio_write_page()
zeroes out too large tail of the page and thus corrupts user data.

Fix the problem by sampling i_size only after the page has been
write-protected in page tables by clear_page_dirty_for_io() call.

Reported-by: Michael Zimmer 
CC: stable@vger.kernel.org
Fixes: cb20d5188366f04d96d2e07b1240cc92170ade40
Signed-off-by: Jan Kara 
Signed-off-by: Theodore Ts'o 
Signed-off-by: Sasha Levin

ext4: keep existing extra fields when inode expands

2017-06-26T02:02:19+00:00

[ Upstream commit 887a9730614727c4fff7cb756711b190593fc1df ]

ext4_expand_extra_isize() should clear only space between old and new
size.

Fixes: 6dd4ee7cab7e # v2.6.23
Cc: stable@vger.kernel.org
Signed-off-by: Konstantin Khlebnikov 
Signed-off-by: Theodore Ts'o 
Signed-off-by: Sasha Levin

ext4: evict inline data when writing to memory map

2017-05-17T19:08:24+00:00

[ Upstream commit 7b4cc9787fe35b3ee2dfb1c35e22eafc32e00c33 ]

Currently the case of writing via mmap to a file with inline data is not
handled.  This is maybe a rare case since it requires a writable memory
map of a very small file, but it is trivial to trigger with on
inline_data filesystem, and it causes the
'BUG_ON(ext4_test_inode_state(inode, EXT4_STATE_MAY_INLINE_DATA));' in
ext4_writepages() to be hit:

    mkfs.ext4 -O inline_data /dev/vdb
    mount /dev/vdb /mnt
    xfs_io -f /mnt/file \
	-c 'pwrite 0 1' \
	-c 'mmap -w 0 1m' \
	-c 'mwrite 0 1' \
	-c 'fsync'

	kernel BUG at fs/ext4/inode.c:2723!
	invalid opcode: 0000 [#1] SMP
	CPU: 1 PID: 2532 Comm: xfs_io Not tainted 4.11.0-rc1-xfstests-00301-g071d9acf3d1f #633
	Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-20170228_101828-anatol 04/01/2014
	task: ffff88003d3a8040 task.stack: ffffc90000300000
	RIP: 0010:ext4_writepages+0xc89/0xf8a
	RSP: 0018:ffffc90000303ca0 EFLAGS: 00010283
	RAX: 0000028410000000 RBX: ffff8800383fa3b0 RCX: ffffffff812afcdc
	RDX: 00000a9d00000246 RSI: ffffffff81e660e0 RDI: 0000000000000246
	RBP: ffffc90000303dc0 R08: 0000000000000002 R09: 869618e8f99b4fa5
	R10: 00000000852287a2 R11: 00000000a03b49f4 R12: ffff88003808e698
	R13: 0000000000000000 R14: 7fffffffffffffff R15: 7fffffffffffffff
	FS:  00007fd3e53094c0(0000) GS:ffff88003e400000(0000) knlGS:0000000000000000
	CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
	CR2: 00007fd3e4c51000 CR3: 000000003d554000 CR4: 00000000003406e0
	Call Trace:
	 ? _raw_spin_unlock+0x27/0x2a
	 ? kvm_clock_read+0x1e/0x20
	 do_writepages+0x23/0x2c
	 ? do_writepages+0x23/0x2c
	 __filemap_fdatawrite_range+0x80/0x87
	 filemap_write_and_wait_range+0x67/0x8c
	 ext4_sync_file+0x20e/0x472
	 vfs_fsync_range+0x8e/0x9f
	 ? syscall_trace_enter+0x25b/0x2d0
	 vfs_fsync+0x1c/0x1e
	 do_fsync+0x31/0x4a
	 SyS_fsync+0x10/0x14
	 do_syscall_64+0x69/0x131
	 entry_SYSCALL64_slow_path+0x25/0x25

We could try to be smart and keep the inline data in this case, or at
least support delayed allocation when allocating the block, but these
solutions would be more complicated and don't seem worthwhile given how
rare this case seems to be.  So just fix the bug by calling
ext4_convert_inline_data() when we're asked to make a page writable, so
that any inline data gets evicted, with the block allocated immediately.

Reported-by: Nick Alcock 
Cc: stable@vger.kernel.org
Reviewed-by: Andreas Dilger 
Signed-off-by: Eric Biggers 
Signed-off-by: Theodore Ts'o 
Signed-off-by: Sasha Levin

fs: Give dentry to inode_change_ok() instead of inode

2016-12-23T13:56:35+00:00

[ Upstream commit 31051c85b5e2aaaf6315f74c72a732673632a905 ]

inode_change_ok() will be resposible for clearing capabilities and IMA
extended attributes and as such will need dentry. Give it as an argument
to inode_change_ok() instead of an inode. Also rename inode_change_ok()
to setattr_prepare() to better relect that it does also some
modifications in addition to checks.

References: CVE-2015-1350
Reviewed-by: Christoph Hellwig 
Signed-off-by: Jan Kara 
Signed-off-by: Philipp Hahn 
Signed-off-by: Sasha Levin

ext4: don't call ext4_should_journal_data() on the journal inode

2016-08-17T16:58:31+00:00

[ Upstream commit 6a7fd522a7c94cdef0a3b08acf8e6702056e635c ]

If ext4_fill_super() fails early, it's possible for ext4_evict_inode()
to call ext4_should_journal_data() before superblock options and flags
are fully set up.  In that case, the iput() on the journal inode can
end up causing a BUG().

Work around this problem by reordering the tests so we only call
ext4_should_journal_data() after we know it's not the journal inode.

Fixes: 2d859db3e4 ("ext4: fix data corruption in inodes with journalled data")
Fixes: 2b405bfa84 ("ext4: fix data=journal fast mount/umount hang")
Cc: Jan Kara 
Cc: stable@vger.kernel.org
Signed-off-by: Vegard Nossum 
Signed-off-by: Theodore Ts'o 
Reviewed-by: Jan Kara 
Signed-off-by: Sasha Levin

ext4: fix deadlock during page writeback

2016-08-17T16:58:31+00:00

[ Upstream commit 646caa9c8e196880b41cd3e3d33a2ebc752bdb85 ]

Commit 06bd3c36a733 (ext4: fix data exposure after a crash) uncovered a
deadlock in ext4_writepages() which was previously much harder to hit.
After this commit xfstest generic/130 reproduces the deadlock on small
filesystems.

The problem happens when ext4_do_update_inode() sets LARGE_FILE feature
and marks current inode handle as synchronous. That subsequently results
in ext4_journal_stop() called from ext4_writepages() to block waiting for
transaction commit while still holding page locks, reference to io_end,
and some prepared bio in mpd structure each of which can possibly block
transaction commit from completing and thus results in deadlock.

Fix the problem by releasing page locks, io_end reference, and
submitting prepared bio before calling ext4_journal_stop().

[ Changed to defer the call to ext4_journal_stop() only if the handle
  is synchronous.  --tytso ]

Reported-and-tested-by: Eryu Guan 
Signed-off-by: Theodore Ts'o 
CC: stable@vger.kernel.org
Signed-off-by: Jan Kara 
Signed-off-by: Sasha Levin

ext4: fix NULL pointer dereference in ext4_mark_inode_dirty()

2016-07-11T03:07:14+00:00

[ Upstream commit 5e1021f2b6dff1a86a468a1424d59faae2bc63c1 ]

ext4_reserve_inode_write() in ext4_mark_inode_dirty() could fail on
error (e.g. EIO) and iloc.bh can be NULL in this case. But the error is
ignored in the following "if" condition and ext4_expand_extra_isize()
might be called with NULL iloc.bh set, which triggers NULL pointer
dereference.

This is uncovered by commit 8b4953e13f4c ("ext4: reserve code points for
the project quota feature"), which enlarges the ext4_inode size, and
run the following script on new kernel but with old mke2fs:

  #/bin/bash
  mnt=/mnt/ext4
  devname=ext4-error
  dev=/dev/mapper/$devname
  fsimg=/home/fs.img

  trap cleanup 0 1 2 3 9 15

  cleanup()
  {
          umount $mnt >/dev/null 2>&1
          dmsetup remove $devname
          losetup -d $backend_dev
          rm -f $fsimg
          exit 0
  }

  rm -f $fsimg
  fallocate -l 1g $fsimg
  backend_dev=`losetup -f --show $fsimg`
  devsize=`blockdev --getsz $backend_dev`

  good_tab="0 $devsize linear $backend_dev 0"
  error_tab="0 $devsize error $backend_dev 0"

  dmsetup create $devname --table "$good_tab"

  mkfs -t ext4 $dev
  mount -t ext4 -o errors=continue,strictatime $dev $mnt

  dmsetup load $devname --table "$error_tab" && dmsetup resume $devname
  echo 3 > /proc/sys/vm/drop_caches
  ls -l $mnt
  exit 0

[ Patch changed to simplify the function a tiny bit. -- Ted ]

Signed-off-by: Eryu Guan 
Signed-off-by: Theodore Ts'o 
Signed-off-by: Sasha Levin