linux-stable.git/fs/ext4, branch v4.3.5

ext4, jbd2: ensure entering into panic after recording an error in superblock

2015-12-15T05:41:07+00:00

commit 4327ba52afd03fc4b5afa0ee1d774c9c5b0e85c5 upstream.

If a EXT4 filesystem utilizes JBD2 journaling and an error occurs, the
journaling will be aborted first and the error number will be recorded
into JBD2 superblock and, finally, the system will enter into the
panic state in "errors=panic" option.  But, in the rare case, this
sequence is little twisted like the below figure and it will happen
that the system enters into panic state, which means the system reset
in mobile environment, before completion of recording an error in the
journal superblock. In this case, e2fsck cannot recognize that the
filesystem failure occurred in the previous run and the corruption
wouldn't be fixed.

Task A                        Task B
ext4_handle_error()
-> jbd2_journal_abort()
  -> __journal_abort_soft()
    -> __jbd2_journal_abort_hard()
    | -> journal->j_flags |= JBD2_ABORT;
    |
    |                         __ext4_abort()
    |                         -> jbd2_journal_abort()
    |                         | -> __journal_abort_soft()
    |                         |   -> if (journal->j_flags & JBD2_ABORT)
    |                         |           return;
    |                         -> panic()
    |
    -> jbd2_journal_update_sb_errno()

Tested-by: Hobin Woo 
Signed-off-by: Daeho Jeong 
Signed-off-by: Theodore Ts'o 
Signed-off-by: Greg Kroah-Hartman

ext4: fix potential use after free in __ext4_journal_stop

2015-12-15T05:41:07+00:00

commit 6934da9238da947628be83635e365df41064b09b upstream.

There is a use-after-free possibility in __ext4_journal_stop() in the
case that we free the handle in the first jbd2_journal_stop() because
we're referencing handle->h_err afterwards. This was introduced in
9705acd63b125dee8b15c705216d7186daea4625 and it is wrong. Fix it by
storing the handle->h_err value beforehand and avoid referencing
potentially freed handle.

Fixes: 9705acd63b125dee8b15c705216d7186daea4625
Signed-off-by: Lukas Czerner 
Reviewed-by: Andreas Dilger 
Signed-off-by: Greg Kroah-Hartman

ext4 crypto: fix bugs in ext4_encrypted_zeroout()

2015-12-15T05:41:07+00:00

commit 36086d43f6575c081067de9855786a2fc91df77b upstream.

Fix multiple bugs in ext4_encrypted_zeroout(), including one that
could cause us to write an encrypted zero page to the wrong location
on disk, potentially causing data and file system corruption.
Fortunately, this tends to only show up in stress tests, but even with
these fixes, we are seeing some test failures with generic/127 --- but
these are now caused by data failures instead of metadata corruption.

Since ext4_encrypted_zeroout() is only used for some optimizations to
keep the extent tree from being too fragmented, and
ext4_encrypted_zeroout() itself isn't all that optimized from a time
or IOPS perspective, disable the extent tree optimization for
encrypted inodes for now.  This prevents the data corruption issues
reported by generic/127 until we can figure out what's going wrong.

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

ext4 crypto: fix memory leak in ext4_bio_write_page()

2015-12-15T05:41:07+00:00

commit 937d7b84dca58f2565715f2c8e52f14c3d65fb22 upstream.

There are times when ext4_bio_write_page() is called even though we
don't actually need to do any I/O.  This happens when ext4_writepage()
gets called by the jbd2 commit path when an inode needs to force its
pages written out in order to provide data=ordered guarantees --- and
a page is backed by an unwritten (e.g., uninitialized) block on disk,
or if delayed allocation means the page's backing store hasn't been
allocated yet.  In that case, we need to skip the call to
ext4_encrypt_page(), since in addition to wasting CPU, it leads to a
bounce page and an ext4 crypto context getting leaked.

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

Merge branch 'akpm' (patches from Andrew)

2015-10-16T18:42:37+00:00

Merge misc fixes from Andrew Morton:
 "6 fixes"

* emailed patches from Andrew Morton :
  sh: add copy_user_page() alias for __copy_user()
  lib/Kconfig: ZLIB_DEFLATE must select BITREVERSE
  mm, dax: fix DAX deadlocks
  memcg: convert threshold to bytes
  builddeb: remove debian/files before build
  mm, fs: obey gfp_mapping for add_to_page_cache()

mm, fs: obey gfp_mapping for add_to_page_cache()

2015-10-16T18:42:28+00:00

Commit 6afdb859b710 ("mm: do not ignore mapping_gfp_mask in page cache
allocation paths") has caught some users of hardcoded GFP_KERNEL used in
the page cache allocation paths.  This, however, wasn't complete and
there were others which went unnoticed.

Dave Chinner has reported the following deadlock for xfs on loop device:
: With the recent merge of the loop device changes, I'm now seeing
: XFS deadlock on my single CPU, 1GB RAM VM running xfs/073.
:
: The deadlocked is as follows:
:
: kloopd1: loop_queue_read_work
:       xfs_file_iter_read
:       lock XFS inode XFS_IOLOCK_SHARED (on image file)
:       page cache read (GFP_KERNEL)
:       radix tree alloc
:       memory reclaim
:       reclaim XFS inodes
:       log force to unpin inodes
:       
:
: xfs-cil/loop1: 
:       xlog_cil_push
:       xlog_write
:       
:               xlog_state_get_iclog_space()
:               
:               
:
: kloopd1: loop_queue_write_work
:       xfs_file_write_iter
:       lock XFS inode XFS_IOLOCK_EXCL (on image file)
:       
:
: i.e. the kloopd, with it's split read and write work queues, has
: introduced a dependency through memory reclaim. i.e. that writes
: need to be able to progress for reads make progress.
:
: The problem, fundamentally, is that mpage_readpages() does a
: GFP_KERNEL allocation, rather than paying attention to the inode's
: mapping gfp mask, which is set to GFP_NOFS.
:
: The didn't used to happen, because the loop device used to issue
: reads through the splice path and that does:
:
:       error = add_to_page_cache_lru(page, mapping, index,
:                       GFP_KERNEL & mapping_gfp_mask(mapping));

This has changed by commit aa4d86163e4 ("block: loop: switch to VFS
ITER_BVEC").

This patch changes mpage_readpage{s} to follow gfp mask set for the
mapping.  There are, however, other places which are doing basically the
same.

lustre:ll_dir_filler is doing GFP_KERNEL from the function which
apparently uses GFP_NOFS for other allocations so let's make this
consistent.

cifs:readpages_get_pages is called from cifs_readpages and
__cifs_readpages_from_fscache called from the same path obeys mapping
gfp.

ramfs_nommu_expand_for_mapping is hardcoding GFP_KERNEL as well
regardless it uses mapping_gfp_mask for the page allocation.

ext4_mpage_readpages is the called from the page cache allocation path
same as read_pages and read_cache_pages

As I've noticed in my previous post I cannot say I would be happy about
sprinkling mapping_gfp_mask all over the place and it sounds like we
should drop gfp_mask argument altogether and use it internally in
__add_to_page_cache_locked that would require all the filesystems to use
mapping gfp consistently which I am not sure is the case here.  From a
quick glance it seems that some file system use it all the time while
others are selective.

Signed-off-by: Michal Hocko 
Reported-by: Dave Chinner 
Cc: "Theodore Ts'o" 
Cc: Ming Lei 
Cc: Andreas Dilger 
Cc: Oleg Drokin 
Cc: Al Viro 
Cc: Christoph Hellwig 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

ext4: Update EXT4_USE_FOR_EXT2 description

2015-09-24T11:27:47+00:00

Configuration option EXT4_USE_FOR_EXT2 has no effect on ext3 support.
Support for ext3 is always included now.

Signed-off-by: Jean Delvare 
Fixes: c290ea01ab ("fs: Remove ext3 filesystem driver")
Cc: Jan Kara 
Cc: Theodore Ts'o 
Cc: Andreas Dilger 
Signed-off-by: Jan Kara

ext4: start transaction before calling into DAX

2015-09-08T22:35:28+00:00

Jan Kara pointed out that in the case where we are writing to a hole, we
can end up with a lock inversion between the page lock and the journal
lock.  We can avoid this by starting the transaction in ext4 before
calling into DAX.  The journal lock nests inside the superblock
pagefault lock, so we have to duplicate that code from dax_fault, like
XFS does.

Signed-off-by: Matthew Wilcox 
Cc: Jan Kara 
Cc: Theodore Ts'o 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

ext4: add ext4_get_block_dax()

2015-09-08T22:35:28+00:00

DAX wants different semantics from any currently-existing ext4 get_block
callback.  Unlike ext4_get_block_write(), it needs to honour the
'create' flag, and unlike ext4_get_block(), it needs to be able to
return unwritten extents.  So introduce a new ext4_get_block_dax() which
has those semantics.

We could also change ext4_get_block_write() to honour the 'create' flag,
but that might have consequences on other users that I do not currently
understand.

Signed-off-by: Matthew Wilcox 
Cc: Theodore Ts'o 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

ext4: use ext4_get_block_write() for DAX

2015-09-08T22:35:28+00:00

DAX relies on the get_block function either zeroing newly allocated
blocks before they're findable by subsequent calls to get_block, or
marking newly allocated blocks as unwritten.  ext4_get_block() cannot
create unwritten extents, but ext4_get_block_write() can.

Signed-off-by: Matthew Wilcox 
Reported-by: Andy Rudoff 
Cc: Theodore Ts'o 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds