linux-toradex.git/fs/ext4/super.c, branch v2.6.32.63

ext4: lock i_mutex when truncating orphan inodes

2013-06-10T09:43:15+00:00

commit 721e3eba21e43532e438652dd8f1fcdfce3187e7 upstream.

Commit c278531d39 added a warning when ext4_flush_unwritten_io() is
called without i_mutex being taken.  It had previously not been taken
during orphan cleanup since races weren't possible at that point in
the mount process, but as a result of this c278531d39, we will now see
a kernel WARN_ON in this case.  Take the i_mutex in
ext4_orphan_cleanup() to suppress this warning.

Reported-by: Alexander Beregalov 
Signed-off-by: "Theodore Ts'o" 
Reviewed-by: Zheng Liu 
Signed-off-by: Greg Kroah-Hartman 
Signed-off-by: Willy Tarreau

ext4: Fix max file size and logical block counting of extent format file

2013-06-10T09:43:12+00:00

commit f17722f917b2f21497deb6edc62fb1683daa08e6 upstream

Kazuya Mio reported that he was able to hit BUG_ON(next == lblock)
in ext4_ext_put_gap_in_cache() while creating a sparse file in extent
format and fill the tail of file up to its end. We will hit the BUG_ON
when we write the last block (2^32-1) into the sparse file.

The root cause of the problem lies in the fact that we specifically set
s_maxbytes so that block at s_maxbytes fit into on-disk extent format,
which is 32 bit long. However, we are not storing start and end block
number, but rather start block number and length in blocks. It means
that in order to cover extent from 0 to EXT_MAX_BLOCK we need
EXT_MAX_BLOCK+1 to fit into len (because we counting block 0 as well) -
and it does not.

The only way to fix it without changing the meaning of the struct
ext4_extent members is, as Kazuya Mio suggested, to lower s_maxbytes
by one fs block so we can cover the whole extent we can get by the
on-disk extent format.

Also in many places EXT_MAX_BLOCK is used as length instead of maximum
logical block number as the name suggests, it is all a bit messy. So
this commit renames it to EXT_MAX_BLOCKS and change its usage in some
places to actually be maximum number of blocks in the extent.

The bug which this commit fixes can be reproduced as follows:

 dd if=/dev/zero of=/mnt/mp1/file bs= count=1 seek=$((2**32-2))
 sync
 dd if=/dev/zero of=/mnt/mp1/file bs= count=1 seek=$((2**32-1))

Reported-by: Kazuya Mio 
Signed-off-by: Lukas Czerner 
Signed-off-by: "Theodore Ts'o" 
[dannf: Applied the backport from RHEL6 to Debian's 2.6.32]
Signed-off-by: Willy Tarreau

ext4: fix undefined behavior in ext4_fill_flex_info()

2012-01-25T21:53:17+00:00

commit d50f2ab6f050311dbf7b8f5501b25f0bf64a439b upstream.

Commit 503358ae01b70ce6909d19dd01287093f6b6271c ("ext4: avoid divide by
zero when trying to mount a corrupted file system") fixes CVE-2009-4307
by performing a sanity check on s_log_groups_per_flex, since it can be
set to a bogus value by an attacker.

	sbi->s_log_groups_per_flex = sbi->s_es->s_log_groups_per_flex;
	groups_per_flex = 1 << sbi->s_log_groups_per_flex;

	if (groups_per_flex < 2) { ... }

This patch fixes two potential issues in the previous commit.

1) The sanity check might only work on architectures like PowerPC.
On x86, 5 bits are used for the shifting amount.  That means, given a
large s_log_groups_per_flex value like 36, groups_per_flex = 1 << 36
is essentially 1 << 4 = 16, rather than 0.  This will bypass the check,
leaving s_log_groups_per_flex and groups_per_flex inconsistent.

2) The sanity check relies on undefined behavior, i.e., oversized shift.
A standard-confirming C compiler could rewrite the check in unexpected
ways.  Consider the following equivalent form, assuming groups_per_flex
is unsigned for simplicity.

	groups_per_flex = 1 << sbi->s_log_groups_per_flex;
	if (groups_per_flex == 0 || groups_per_flex == 1) {

We compile the code snippet using Clang 3.0 and GCC 4.6.  Clang will
completely optimize away the check groups_per_flex == 0, leaving the
patched code as vulnerable as the original.  GCC keeps the check, but
there is no guarantee that future versions will do the same.

Signed-off-by: Xi Wang 
Signed-off-by: "Theodore Ts'o" 
Signed-off-by: Greg Kroah-Hartman

ext4: Fix optional-arg mount options

2010-08-13T20:20:18+00:00

commit 15121c18a22ae483279f76dc9e554334b800d0f7 upstream.

We have 2 mount options, "barrier" and "auto_da_alloc" which may or
may not take a 1/0 argument.  This causes the ext4 superblock mount
code to subtract uninitialized pointers and pass the result to
kmalloc, which results in very noisy failures.

Per Ted's suggestion, initialize the args struct so that
we know whether match_token() found an argument for the
option, and skip match_int() if not.

Also, return error (0) from parse_options if we thought
we found an argument, but match_int() Fails.

Reported-by: Michael S. Tsirkin 
Signed-off-by: Eric Sandeen 
Signed-off-by: "Theodore Ts'o" 
Acked-by: Jeff Mahoney 
Signed-off-by: Greg Kroah-Hartman

ext4: fix freeze deadlock under IO

2010-08-13T20:19:51+00:00

commit 437f88cc031ffe7f37f3e705367f4fe1f4be8b0f upstream.

Commit 6b0310fbf087ad6 caused a regression resulting in deadlocks
when freezing a filesystem which had active IO; the vfs_check_frozen
level (SB_FREEZE_WRITE) did not let the freeze-related IO syncing
through.  Duh.

Changing the test to FREEZE_TRANS should let the normal freeze
syncing get through the fs, but still block any transactions from
starting once the fs is completely frozen.

I tested this by running fsstress in the background while periodically
snapshotting the fs and running fsck on the result.  I ran into
occasional deadlocks, but different ones.  I think this is a
fine fix for the problem at hand, and the other deadlocky things
will need more investigation.

Reported-by: Phillip Susi 
Signed-off-by: Eric Sandeen 
Signed-off-by: "Theodore Ts'o" 
Signed-off-by: Greg Kroah-Hartman

ext4: Use bitops to read/modify i_flags in struct ext4_inode_info

2010-08-02T17:21:22+00:00

commit 12e9b892002d9af057655d35b44db8ee9243b0dc upstream (as of v2.6.34-git13)

At several places we modify EXT4_I(inode)->i_flags without holding
i_mutex (ext4_do_update_inode, ...). These modifications are racy and
we can lose updates to i_flags. So convert handling of i_flags to use
bitops which are atomic.

https://bugzilla.kernel.org/show_bug.cgi?id=15792

Signed-off-by: Dmitry Monakhov 
Signed-off-by: "Theodore Ts'o" 
Signed-off-by: Greg Kroah-Hartman

ext4: Show journal_checksum option

2010-08-02T17:21:22+00:00

commit 39a4bade8c1826b658316d66ee81c09b0a4d7d42 upstream (as of v2.6.34-git13)

We failed to show journal_checksum option in /proc/mounts. Fix it.

Signed-off-by: Jan Kara 
Signed-off-by: "Theodore Ts'o" 
Signed-off-by: Greg Kroah-Hartman

ext4: Remove extraneous newlines in ext4_msg() calls

2010-08-02T17:21:21+00:00

commit fbe845ddf368f77f86aa7500f8fd2690f54c66a8 upstream (as of v2.6.34-git13)

Addresses-Google-Bug: #2562325

Signed-off-by: Curt Wohlgemuth 
Signed-off-by: "Theodore Ts'o" 
Signed-off-by: Greg Kroah-Hartman

ext4: init statistics after journal recovery

2010-08-02T17:21:20+00:00

commit 84061e07c5fbbbf9dc8aef8fb750fc3a2dfc31f3 upstream (as of v2.6.34-git13)

Currently block/inode/dir counters initialized before journal was
recovered. In fact after journal recovery this info will probably
change. And freeblocks it critical for correct delalloc mode
accounting.

https://bugzilla.kernel.org/show_bug.cgi?id=15768

Signed-off-by: Dmitry Monakhov 
Acked-by: Jan Kara 
Signed-off-by: "Theodore Ts'o" 
Signed-off-by: Greg Kroah-Hartman

ext4: don't return to userspace after freezing the fs with a mutex held

2010-08-02T17:21:19+00:00

commit 6b0310fbf087ad6e9e3b8392adca97cd77184084 upstream (as of v2.6.34-git13)

ext4_freeze() used jbd2_journal_lock_updates() which takes
the j_barrier mutex, and then returns to userspace.  The
kernel does not like this:

================================================
[ BUG: lock held when returning to user space! ]
------------------------------------------------
lvcreate/1075 is leaving the kernel with locks still held!
1 lock held by lvcreate/1075:
 #0:  (&journal->j_barrier){+.+...}, at: []
jbd2_journal_lock_updates+0xe1/0xf0

Use vfs_check_frozen() added to ext4_journal_start_sb() and
ext4_force_commit() instead.

Addresses-Red-Hat-Bugzilla: #568503

Signed-off-by: Eric Sandeen 
Signed-off-by: "Theodore Ts'o" 
Signed-off-by: Greg Kroah-Hartman