linux-stable.git/fs/ext4, branch v3.12.44

ext4: check for zero length extent explicitly

2015-06-03T09:33:11+00:00

commit 2f974865ffdfe7b9f46a9940836c8b167342563d upstream.

The following commit introduced a bug when checking for zero length extent

5946d08 ext4: check for overlapping extents in ext4_valid_extent_entries()

Zero length extent could pass the check if lblock is zero.

Adding the explicit check for zero length back.

Signed-off-by: Eryu Guan 
Signed-off-by: Theodore Ts'o 
Signed-off-by: Jiri Slaby

ext4: fix NULL pointer dereference when journal restart fails

2015-06-03T09:33:11+00:00

commit 9d506594069355d1fb2de3f9104667312ff08ed3 upstream.

Currently when journal restart fails, we'll have the h_transaction of
the handle set to NULL to indicate that the handle has been effectively
aborted. We handle this situation quietly in the jbd2_journal_stop() and just
free the handle and exit because everything else has been done before we
attempted (and failed) to restart the journal.

Unfortunately there are a number of problems with that approach
introduced with commit

41a5b913197c "jbd2: invalidate handle if jbd2_journal_restart()
fails"

First of all in ext4 jbd2_journal_stop() will be called through
__ext4_journal_stop() where we would try to get a hold of the superblock
by dereferencing h_transaction which in this case would lead to NULL
pointer dereference and crash.

In addition we're going to free the handle regardless of the refcount
which is bad as well, because others up the call chain will still
reference the handle so we might potentially reference already freed
memory.

Moreover it's expected that we'll get aborted handle as well as detached
handle in some of the journalling function as the error propagates up
the stack, so it's unnecessary to call WARN_ON every time we get
detached handle.

And finally we might leak some memory by forgetting to free reserved
handle in jbd2_journal_stop() in the case where handle was detached from
the transaction (h_transaction is NULL).

Fix the NULL pointer dereference in __ext4_journal_stop() by just
calling jbd2_journal_stop() quietly as suggested by Jan Kara. Also fix
the potential memory leak in jbd2_journal_stop() and use proper
handle refcounting before we attempt to free it to avoid use-after-free
issues.

And finally remove all WARN_ON(!transaction) from the code so that we do
not get random traces when something goes wrong because when journal
restart fails we will get to some of those functions.

Signed-off-by: Lukas Czerner 
Signed-off-by: Theodore Ts'o 
Reviewed-by: Jan Kara 
Signed-off-by: Jiri Slaby

ext4: fix data corruption caused by unwritten and delayed extents

2015-05-15T07:10:49+00:00

commit d2dc317d564a46dfc683978a2e5a4f91434e9711 upstream.

Currently it is possible to lose whole file system block worth of data
when we hit the specific interaction with unwritten and delayed extents
in status extent tree.

The problem is that when we insert delayed extent into extent status
tree the only way to get rid of it is when we write out delayed buffer.
However there is a limitation in the extent status tree implementation
so that when inserting unwritten extent should there be even a single
delayed block the whole unwritten extent would be marked as delayed.

At this point, there is no way to get rid of the delayed extents,
because there are no delayed buffers to write out. So when a we write
into said unwritten extent we will convert it to written, but it still
remains delayed.

When we try to write into that block later ext4_da_map_blocks() will set
the buffer new and delayed and map it to invalid block which causes
the rest of the block to be zeroed loosing already written data.

For now we can fix this by simply not allowing to set delayed status on
written extent in the extent status tree. Also add WARN_ON() to make
sure that we notice if this happens in the future.

This problem can be easily reproduced by running the following xfs_io.

xfs_io -f -c "pwrite -S 0xaa 4096 2048" \
          -c "falloc 0 131072" \
          -c "pwrite -S 0xbb 65536 2048" \
          -c "fsync" /mnt/test/fff

echo 3 > /proc/sys/vm/drop_caches
xfs_io -c "pwrite -S 0xdd 67584 2048" /mnt/test/fff

This can be theoretically also reproduced by at random by running fsx,
but it's not very reliable, though on machines with bigger page size
(like ppc) this can be seen more often (especially xfstest generic/127)

Signed-off-by: Lukas Czerner 
Signed-off-by: Theodore Ts'o 
Signed-off-by: Jiri Slaby

ext4: make fsync to sync parent dir in no-journal for real this time

2015-05-04T09:50:05+00:00

commit e12fb97222fc41e8442896934f76d39ef99b590a upstream.

Previously commit 14ece1028b3ed53ffec1b1213ffc6acaf79ad77c added a
support for for syncing parent directory of newly created inodes to
make sure that the inode is not lost after a power failure in
no-journal mode.

However this does not work in majority of cases, namely:
 - if the directory has inline data
 - if the directory is already indexed
 - if the directory already has at least one block and:
	- the new entry fits into it
	- or we've successfully converted it to indexed

So in those cases we might lose the inode entirely even after fsync in
the no-journal mode. This also includes ext2 default mode obviously.

I've noticed this while running xfstest generic/321 and even though the
test should fail (we need to run fsck after a crash in no-journal mode)
I could not find a newly created entries even when if it was fsynced
before.

Fix this by adjusting the ext4_add_entry() successful exit paths to set
the inode EXT4_STATE_NEWENTRY so that fsync has the chance to fsync the
parent directory as well.

Signed-off-by: Lukas Czerner 
Signed-off-by: Theodore Ts'o 
Reviewed-by: Jan Kara 
Cc: Frank Mayhar 
Signed-off-by: Jiri Slaby

ext4: prevent bugon on race between write/fcntl

2015-02-09T09:19:55+00:00

commit a41537e69b4aa43f0fea02498c2595a81267383b upstream.

O_DIRECT flags can be toggeled via fcntl(F_SETFL). But this value checked
twice inside ext4_file_write_iter() and __generic_file_write() which
result in BUG_ON inside ext4_direct_IO.

Let's initialize iocb->private unconditionally.

TESTCASE: xfstest:generic/036  https://patchwork.ozlabs.org/patch/402445/

#TYPICAL STACK TRACE:
kernel BUG at fs/ext4/inode.c:2960!
invalid opcode: 0000 [#1] SMP
Modules linked in: brd iTCO_wdt lpc_ich mfd_core igb ptp dm_mirror dm_region_hash dm_log dm_mod
CPU: 6 PID: 5505 Comm: aio-dio-fcntl-r Not tainted 3.17.0-rc2-00176-gff5c017 #161
Hardware name: Intel Corporation W2600CR/W2600CR, BIOS SE5C600.86B.99.99.x028.061320111235 06/13/2011
task: ffff88080e95a7c0 ti: ffff88080f908000 task.ti: ffff88080f908000
RIP: 0010:[]  [] ext4_direct_IO+0x162/0x3d0
RSP: 0018:ffff88080f90bb58  EFLAGS: 00010246
RAX: 0000000000000400 RBX: ffff88080fdb2a28 RCX: 00000000a802c818
RDX: 0000040000080000 RSI: ffff88080d8aeb80 RDI: 0000000000000001
RBP: ffff88080f90bbc8 R08: 0000000000000000 R09: 0000000000001581
R10: 0000000000000000 R11: 0000000000000000 R12: ffff88080d8aeb80
R13: ffff88080f90bbf8 R14: ffff88080fdb28c8 R15: ffff88080fdb2a28
FS:  00007f23b2055700(0000) GS:ffff880818400000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f23b2045000 CR3: 000000080cedf000 CR4: 00000000000407e0
Stack:
 ffff88080f90bb98 0000000000000000 7ffffffffffffffe ffff88080fdb2c30
 0000000000000200 0000000000000200 0000000000000001 0000000000000200
 ffff88080f90bbc8 ffff88080fdb2c30 ffff88080f90be08 0000000000000200
Call Trace:
 [] generic_file_direct_write+0xed/0x180
 [] __generic_file_write_iter+0x222/0x370
 [] ext4_file_write_iter+0x34b/0x400
 [] ? aio_run_iocb+0x239/0x410
 [] ? aio_run_iocb+0x239/0x410
 [] ? local_clock+0x25/0x30
 [] ? __lock_acquire+0x274/0x700
 [] ? ext4_unwritten_wait+0xb0/0xb0
 [] aio_run_iocb+0x286/0x410
 [] ? local_clock+0x25/0x30
 [] ? lock_release_holdtime+0x29/0x190
 [] ? lookup_ioctx+0x4b/0xf0
 [] do_io_submit+0x55b/0x740
 [] ? do_io_submit+0x3ca/0x740
 [] SyS_io_submit+0x10/0x20
 [] system_call_fastpath+0x16/0x1b
Code: 01 48 8b 80 f0 01 00 00 48 8b 18 49 8b 45 10 0f 85 f1 01 00 00 48 03 45 c8 48 3b 43 48 0f 8f e3 01 00 00 49 83 7c
24 18 00 75 04 <0f> 0b eb fe f0 ff 83 ec 01 00 00 49 8b 44 24 18 8b 00 85 c0 89
RIP  [] ext4_direct_IO+0x162/0x3d0
 RSP 

Reported-by: Sasha Levin 
Signed-off-by: Theodore Ts'o 
Signed-off-by: Dmitry Monakhov 
[hujianyang: Backported to 3.10
 - Move initialization of iocb->private to ext4_file_write() as we don't
   have ext4_file_write_iter(), which is introduced by commit 9b884164.
 - Adjust context to make 'overwrite' changes apply to ext4_file_dio_write()
   as ext4_file_dio_write() is not move into ext4_file_write()]
Signed-off-by: hujianyang 
Signed-off-by: Jiri Slaby

ext4: atomically set inode->i_flags in ext4_set_inode_flags()

2014-12-03T10:58:43+00:00

commit 5f16f3225b06242a9ee876f07c1c9b6ed36a22b6 upstream.

Use cmpxchg() to atomically set i_flags instead of clearing out the
S_IMMUTABLE, S_APPEND, etc. flags and then setting them from the
EXT4_IMMUTABLE_FL, EXT4_APPEND_FL flags, since this opens up a race
where an immutable file has the immutable flag cleared for a brief
window of time.

js: there is no change for ext4. This patch defines merely
    inode_set_flags for jffs in the next patch. I wonder why do we
    have both inode_set_flags and set_mask_bits? Looks like an
    improperly resolved merge conflict.

Reported-by: John Sullivan 
Signed-off-by: "Theodore Ts'o" 
Cc: stable@kernel.org
Signed-off-by: Jiri Slaby

fix O_SYNC|O_APPEND syncing the wrong range on write()

2014-12-03T10:58:41+00:00

commit d311d79de305f1ada47cadd672e6ed1b28a949eb upstream.

It actually goes back to 2004 ([PATCH] Concurrent O_SYNC write support)
when sync_page_range() had been introduced; generic_file_write{,v}() correctly
synced
	pos_after_write - written .. pos_after_write - 1
but generic_file_aio_write() synced
	pos_before_write .. pos_before_write + written - 1
instead.  Which is not the same thing with O_APPEND, obviously.
A couple of years later correct variant had been killed off when
everything switched to use of generic_file_aio_write().

All users of generic_file_aio_write() are affected, and the same bug
has been copied into other instances of ->aio_write().

The fix is trivial; the only subtle point is that generic_write_sync()
ought to be inlined to avoid calculations useless for the majority of
calls.

Signed-off-by: Al Viro 
Signed-off-by: Jiri Slaby

ext4: fix oops when loading block bitmap failed

2014-11-13T18:02:37+00:00

commit 599a9b77ab289d85c2d5c8607624efbe1f552b0f upstream.

When we fail to load block bitmap in __ext4_new_inode() we will
dereference NULL pointer in ext4_journal_get_write_access(). So check
for error from ext4_read_block_bitmap().

Coverity-id: 989065
Signed-off-by: Jan Kara 
Signed-off-by: Theodore Ts'o 
Signed-off-by: Jiri Slaby

ext4: enable journal checksum when metadata checksum feature enabled

2014-11-13T18:02:37+00:00

commit 98c1a7593fa355fda7f5a5940c8bf5326ca964ba upstream.

If metadata checksumming is turned on for the FS, we need to tell the
journal to use checksumming too.

Signed-off-by: Darrick J. Wong 
Signed-off-by: Theodore Ts'o 
Signed-off-by: Jiri Slaby

ext4: fix overflow when updating superblock backups after resize

2014-11-13T18:02:36+00:00

commit 9378c6768e4fca48971e7b6a9075bc006eda981d upstream.

When there are no meta block groups update_backups() will compute the
backup block in 32-bit arithmetics thus possibly overflowing the block
number and corrupting the filesystem. OTOH filesystems without meta
block groups larger than 16 TB should be rare. Fix the problem by doing
the counting in 64-bit arithmetics.

Coverity-id: 741252
Signed-off-by: Jan Kara 
Signed-off-by: Theodore Ts'o 
Reviewed-by: Lukas Czerner 
Signed-off-by: Jiri Slaby