linux-toradex.git/fs/ext3, branch v2.6.32.2

ext3: Fix data / filesystem corruption when write fails to copy data

2009-12-18T22:05:39+00:00

commit 68eb3db08344286733adac48304d9fb7a0e53b27 upstream.

When ext3_write_begin fails after allocating some blocks or
generic_perform_write fails to copy data to write, we truncate blocks already
instantiated beyond i_size. Although these blocks were never inside i_size, we
have to truncate pagecache of these blocks so that corresponding buffers get
unmapped. Otherwise subsequent __block_prepare_write (called because we are
retrying the write) will find the buffers mapped, not call ->get_block, and
thus the page will be backed by already freed blocks leading to filesystem and
data corruption.

Reported-by: James Y Knight 
Signed-off-by: Jan Kara 
Signed-off-by: Greg Kroah-Hartman

ext3: Wait for proper transaction commit on fsync

2009-11-11T14:22:49+00:00

We cannot rely on buffer dirty bits during fsync because pdflush can come
before fsync is called and clear dirty bits without forcing a transaction
commit. What we do is that we track which transaction has last changed
the inode and which transaction last changed allocation and force it to
disk on fsync.

Signed-off-by: Jan Kara 
Reviewed-by: Aneesh Kumar K.V

ext3: retry failed direct IO allocations

2009-11-11T14:22:49+00:00

On a 256M 4k block filesystem, doing this in a loop:

    dd if=/dev/zero of=test oflag=direct bs=1M count=64
    rm -f test

eventually leads to spurious ENOSPC:

    dd: writing `test': No space left on device

As with other block allocation callers, it looks like we need to
potentially retry the allocations on the initial ENOSPC.

A similar patch went into ext4 (commit
fbbf69456619de5d251cb9f1df609069178c62d5)

Signed-off-by: Eric Sandeen 
Signed-off-by: Jan Kara

ext3: Don't update superblock write time when filesystem is read-only

2009-10-12T22:06:43+00:00

This avoids updating the superblock write time when we are mounting
the root file system read/only but we need to replay the journal; at
that point, for people who are east of GMT and who make their clock
tick in localtime for Windows bug-for-bug compatibility, and this will
cause e2fsck to complain and force a full file system check.

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

Merge branch 'hwpoison' of git://git.kernel.org/pub/scm/linux/kernel/git/ak/linux-mce-2.6

2009-09-24T14:53:22+00:00

* 'hwpoison' of git://git.kernel.org/pub/scm/linux/kernel/git/ak/linux-mce-2.6: (21 commits)
  HWPOISON: Enable error_remove_page on btrfs
  HWPOISON: Add simple debugfs interface to inject hwpoison on arbitary PFNs
  HWPOISON: Add madvise() based injector for hardware poisoned pages v4
  HWPOISON: Enable error_remove_page for NFS
  HWPOISON: Enable .remove_error_page for migration aware file systems
  HWPOISON: The high level memory error handler in the VM v7
  HWPOISON: Add PR_MCE_KILL prctl to control early kill behaviour per process
  HWPOISON: shmem: call set_page_dirty() with locked page
  HWPOISON: Define a new error_remove_page address space op for async truncation
  HWPOISON: Add invalidate_inode_page
  HWPOISON: Refactor truncate to allow direct truncating of page v2
  HWPOISON: check and isolate corrupted free pages v2
  HWPOISON: Handle hardware poisoned pages in try_to_unmap
  HWPOISON: Use bitmask/action code for try_to_unmap behaviour
  HWPOISON: x86: Add VM_FAULT_HWPOISON handling to x86 page fault handler v2
  HWPOISON: Add poison check to page fault handling
  HWPOISON: Add basic support for poisoned pages in fault handler v3
  HWPOISON: Add new SIGBUS error codes for hardware poison signals
  HWPOISON: Add support for poison swap entries v2
  HWPOISON: Export some rmap vma locking to outside world
  ...

const: make struct super_block::s_qcop const

2009-09-22T14:17:24+00:00

Signed-off-by: Alexey Dobriyan 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

const: make struct super_block::dq_op const

2009-09-22T14:17:24+00:00

Signed-off-by: Alexey Dobriyan 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

ext3: Flush disk caches on fsync when needed

2009-09-16T15:44:11+00:00

In case we fsync() a file and inode is not dirty, we don't force a transaction
to disk and hence don't flush disk caches. Thus file data could be just in disk
caches and not on persistent storage. Fix the problem by flushing disk caches
if we didn't force a transaction commit.

Signed-off-by: Jan Kara

ext3: Add locking to ext3_do_update_inode

2009-09-16T15:44:11+00:00

I've been struggling with this off and on while I've been testing the
data=guarded work.  The symptom is corrupted orphan lists and inodes
with the wrong i_size stored on disk.  I was convinced the
data=guarded code was just missing a call to ext3_mark_inode_dirty, but
tracing showed the i_disksize I was sending to ext3_mark_inode_dirty
wasn't actually making it to the drive.

ext3_mark_inode_dirty can be called without locks held (atime updates
and a few others), so the data=guarded code uses locks while updating
the in-memory inode, and then calls ext3_mark_inode_dirty
without any locks held.

But, ext3_mark_inode_dirty has no internal locking to make sure that
only one CPU is updating the buffer head at a time.  Generally this
works out ok because everyone that changes the inode then calls
ext3_mark_inode_dirty themselves.  Even though it races, eventually
someone updates the buffer heads and things move on.

But there is still a risk of the wrong values getting in, and the
data=guarded code seems to hit the race very often.

Since everyone that changes the inode also logs it, it should be
possible to fix this with some memory barriers.  I'll leave that as an
exercise to the reader and lock the buffer head instead.

It it probably a good idea to have a different patch series for lockless
bit flipping on the ext3 i_state field.  ext3_do_update_inode &= clears
EXT3_STATE_NEW without any locks held.

Signed-off-by: Chris Mason 
Signed-off-by: Jan Kara

ext3: Fix possible deadlock between ext3_truncate() and ext3_get_blocks()

2009-09-16T15:44:11+00:00

During truncate we are sometimes forced to start a new transaction as the
amount of blocks to be journaled is both quite large and hard to predict. So
far we restarted a transaction while holding truncate_mutex and that violates
lock ordering because truncate_mutex ranks below transaction start (and it
can lead to a real deadlock with ext3_get_blocks() allocating new blocks
from ext3_writepage()).

Luckily, the problem is easy to fix: We just drop the truncate_mutex before
restarting the transaction and acquire it afterwards. We are safe to do this as
by the time ext3_truncate() is called, all the page cache for the truncated
part of the file is dropped and so writepage() cannot come and allocate new
blocks in the part of the file we are truncating. The rest of writers is
stopped by us holding i_mutex.

Signed-off-by: Jan Kara