Commit Graph

1715 Commits

Author SHA1 Message Date
Konstantin Khlebnikov 0b173bc4da mm: kill vma flag VM_CAN_NONLINEAR
Move actual pte filling for non-linear file mappings into the new special
vma operation: ->remap_pages().

Filesystems must implement this method to get non-linear mapping support,
if it uses filemap_fault() then generic_file_remap_pages() can be used.

Now device drivers can implement this method and obtain nonlinear vma support.

Signed-off-by: Konstantin Khlebnikov <khlebnikov@openvz.org>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Carsten Otte <cotte@de.ibm.com>
Cc: Chris Metcalf <cmetcalf@tilera.com>	#arch/tile
Cc: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: Eric Paris <eparis@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: James Morris <james.l.morris@oracle.com>
Cc: Jason Baron <jbaron@redhat.com>
Cc: Kentaro Takeda <takedakn@nttdata.co.jp>
Cc: Matt Helsley <matthltc@us.ibm.com>
Cc: Nick Piggin <npiggin@kernel.dk>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Robert Richter <robert.richter@amd.com>
Cc: Suresh Siddha <suresh.b.siddha@intel.com>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: Venkatesh Pallipadi <venki@google.com>
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-10-09 16:22:17 +09:00
Linus Torvalds 6432f21284 The big new feature added this time is supporting online resizing
using the meta_bg feature.  This allows us to resize file systems
 which are greater than 16TB.  In addition, the speed of online
 resizing has been improved in general.
 
 We also fix a number of races, some of which could lead to deadlocks,
 in ext4's Asynchronous I/O and online defrag support, thanks to good
 work by Dmitry Monakhov.
 
 There are also a large number of more minor bug fixes and cleanups
 from a number of other ext4 contributors, quite of few of which have
 submitted fixes for the first time.
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Merge tag 'ext4_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4

Pull ext4 updates from Ted Ts'o:
 "The big new feature added this time is supporting online resizing
  using the meta_bg feature.  This allows us to resize file systems
  which are greater than 16TB.  In addition, the speed of online
  resizing has been improved in general.

  We also fix a number of races, some of which could lead to deadlocks,
  in ext4's Asynchronous I/O and online defrag support, thanks to good
  work by Dmitry Monakhov.

  There are also a large number of more minor bug fixes and cleanups
  from a number of other ext4 contributors, quite of few of which have
  submitted fixes for the first time."

* tag 'ext4_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4: (69 commits)
  ext4: fix ext4_flush_completed_IO wait semantics
  ext4: fix mtime update in nodelalloc mode
  ext4: fix ext_remove_space for punch_hole case
  ext4: punch_hole should wait for DIO writers
  ext4: serialize truncate with owerwrite DIO workers
  ext4: endless truncate due to nonlocked dio readers
  ext4: serialize unlocked dio reads with truncate
  ext4: serialize dio nonlocked reads with defrag workers
  ext4: completed_io locking cleanup
  ext4: fix unwritten counter leakage
  ext4: give i_aiodio_unwritten a more appropriate name
  ext4: ext4_inode_info diet
  ext4: convert to use leXX_add_cpu()
  ext4: ext4_bread usage audit
  fs: reserve fallocate flag codepoint
  ext4: remove redundant offset check in mext_check_arguments()
  ext4: don't clear orphan list on ro mount with errors
  jbd2: fix assertion failure in commit code due to lacking transaction credits
  ext4: release donor reference when EXT4_IOC_MOVE_EXT ioctl fails
  ext4: enable FITRIM ioctl on bigalloc file system
  ...
2012-10-08 06:36:39 +09:00
Dmitry Monakhov c278531d39 ext4: fix ext4_flush_completed_IO wait semantics
BUG #1) All places where we call ext4_flush_completed_IO are broken
    because buffered io and DIO/AIO goes through three stages
    1) submitted io,
    2) completed io (in i_completed_io_list) conversion pended
    3) finished  io (conversion done)
    And by calling ext4_flush_completed_IO we will flush only
    requests which were in (2) stage, which is wrong because:
     1) punch_hole and truncate _must_ wait for all outstanding unwritten io
      regardless to it's state.
     2) fsync and nolock_dio_read should also wait because there is
        a time window between end_page_writeback() and ext4_add_complete_io()
        As result integrity fsync is broken in case of buffered write
        to fallocated region:
        fsync                                      blkdev_completion
	 ->filemap_write_and_wait_range
                                                   ->ext4_end_bio
                                                     ->end_page_writeback
          <-- filemap_write_and_wait_range return
	 ->ext4_flush_completed_IO
   	 sees empty i_completed_io_list but pended
   	 conversion still exist
                                                     ->ext4_add_complete_io

BUG #2) Race window becomes wider due to the 'ext4: completed_io
locking cleanup V4' patch series

This patch make following changes:
1) ext4_flush_completed_io() now first try to flush completed io and when
   wait for any outstanding unwritten io via ext4_unwritten_wait()
2) Rename function to more appropriate name.
3) Assert that all callers of ext4_flush_unwritten_io should hold i_mutex to
   prevent endless wait

Signed-off-by: Dmitry Monakhov <dmonakhov@openvz.org>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Reviewed-by: Jan Kara <jack@suse.cz>
2012-10-05 11:31:55 -04:00
Linus Torvalds aab174f0df Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
Pull vfs update from Al Viro:

 - big one - consolidation of descriptor-related logics; almost all of
   that is moved to fs/file.c

   (BTW, I'm seriously tempted to rename the result to fd.c.  As it is,
   we have a situation when file_table.c is about handling of struct
   file and file.c is about handling of descriptor tables; the reasons
   are historical - file_table.c used to be about a static array of
   struct file we used to have way back).

   A lot of stray ends got cleaned up and converted to saner primitives,
   disgusting mess in android/binder.c is still disgusting, but at least
   doesn't poke so much in descriptor table guts anymore.  A bunch of
   relatively minor races got fixed in process, plus an ext4 struct file
   leak.

 - related thing - fget_light() partially unuglified; see fdget() in
   there (and yes, it generates the code as good as we used to have).

 - also related - bits of Cyrill's procfs stuff that got entangled into
   that work; _not_ all of it, just the initial move to fs/proc/fd.c and
   switch of fdinfo to seq_file.

 - Alex's fs/coredump.c spiltoff - the same story, had been easier to
   take that commit than mess with conflicts.  The rest is a separate
   pile, this was just a mechanical code movement.

 - a few misc patches all over the place.  Not all for this cycle,
   there'll be more (and quite a few currently sit in akpm's tree)."

Fix up trivial conflicts in the android binder driver, and some fairly
simple conflicts due to two different changes to the sock_alloc_file()
interface ("take descriptor handling from sock_alloc_file() to callers"
vs "net: Providing protocol type via system.sockprotoname xattr of
/proc/PID/fd entries" adding a dentry name to the socket)

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (72 commits)
  MAX_LFS_FILESIZE should be a loff_t
  compat: fs: Generic compat_sys_sendfile implementation
  fs: push rcu_barrier() from deactivate_locked_super() to filesystems
  btrfs: reada_extent doesn't need kref for refcount
  coredump: move core dump functionality into its own file
  coredump: prevent double-free on an error path in core dumper
  usb/gadget: fix misannotations
  fcntl: fix misannotations
  ceph: don't abuse d_delete() on failure exits
  hypfs: ->d_parent is never NULL or negative
  vfs: delete surplus inode NULL check
  switch simple cases of fget_light to fdget
  new helpers: fdget()/fdput()
  switch o2hb_region_dev_write() to fget_light()
  proc_map_files_readdir(): don't bother with grabbing files
  make get_file() return its argument
  vhost_set_vring(): turn pollstart/pollstop into bool
  switch prctl_set_mm_exe_file() to fget_light()
  switch xfs_find_handle() to fget_light()
  switch xfs_swapext() to fget_light()
  ...
2012-10-02 20:25:04 -07:00
Kirill A. Shutemov 8c0a853770 fs: push rcu_barrier() from deactivate_locked_super() to filesystems
There's no reason to call rcu_barrier() on every
deactivate_locked_super().  We only need to make sure that all delayed rcu
free inodes are flushed before we destroy related cache.

Removing rcu_barrier() from deactivate_locked_super() affects some fast
paths.  E.g.  on my machine exit_group() of a last process in IPC
namespace takes 0.07538s.  rcu_barrier() takes 0.05188s of that time.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-10-02 21:35:55 -04:00
Linus Torvalds 437589a74b Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace
Pull user namespace changes from Eric Biederman:
 "This is a mostly modest set of changes to enable basic user namespace
  support.  This allows the code to code to compile with user namespaces
  enabled and removes the assumption there is only the initial user
  namespace.  Everything is converted except for the most complex of the
  filesystems: autofs4, 9p, afs, ceph, cifs, coda, fuse, gfs2, ncpfs,
  nfs, ocfs2 and xfs as those patches need a bit more review.

  The strategy is to push kuid_t and kgid_t values are far down into
  subsystems and filesystems as reasonable.  Leaving the make_kuid and
  from_kuid operations to happen at the edge of userspace, as the values
  come off the disk, and as the values come in from the network.
  Letting compile type incompatible compile errors (present when user
  namespaces are enabled) guide me to find the issues.

  The most tricky areas have been the places where we had an implicit
  union of uid and gid values and were storing them in an unsigned int.
  Those places were converted into explicit unions.  I made certain to
  handle those places with simple trivial patches.

  Out of that work I discovered we have generic interfaces for storing
  quota by projid.  I had never heard of the project identifiers before.
  Adding full user namespace support for project identifiers accounts
  for most of the code size growth in my git tree.

  Ultimately there will be work to relax privlige checks from
  "capable(FOO)" to "ns_capable(user_ns, FOO)" where it is safe allowing
  root in a user names to do those things that today we only forbid to
  non-root users because it will confuse suid root applications.

  While I was pushing kuid_t and kgid_t changes deep into the audit code
  I made a few other cleanups.  I capitalized on the fact we process
  netlink messages in the context of the message sender.  I removed
  usage of NETLINK_CRED, and started directly using current->tty.

  Some of these patches have also made it into maintainer trees, with no
  problems from identical code from different trees showing up in
  linux-next.

  After reading through all of this code I feel like I might be able to
  win a game of kernel trivial pursuit."

Fix up some fairly trivial conflicts in netfilter uid/git logging code.

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace: (107 commits)
  userns: Convert the ufs filesystem to use kuid/kgid where appropriate
  userns: Convert the udf filesystem to use kuid/kgid where appropriate
  userns: Convert ubifs to use kuid/kgid
  userns: Convert squashfs to use kuid/kgid where appropriate
  userns: Convert reiserfs to use kuid and kgid where appropriate
  userns: Convert jfs to use kuid/kgid where appropriate
  userns: Convert jffs2 to use kuid and kgid where appropriate
  userns: Convert hpfs to use kuid and kgid where appropriate
  userns: Convert btrfs to use kuid/kgid where appropriate
  userns: Convert bfs to use kuid/kgid where appropriate
  userns: Convert affs to use kuid/kgid wherwe appropriate
  userns: On alpha modify linux_to_osf_stat to use convert from kuids and kgids
  userns: On ia64 deal with current_uid and current_gid being kuid and kgid
  userns: On ppc convert current_uid from a kuid before printing.
  userns: Convert s390 getting uid and gid system calls to use kuid and kgid
  userns: Convert s390 hypfs to use kuid and kgid where appropriate
  userns: Convert binder ipc to use kuids
  userns: Teach security_path_chown to take kuids and kgids
  userns: Add user namespace support to IMA
  userns: Convert EVM to deal with kuids and kgids in it's hmac computation
  ...
2012-10-02 11:11:09 -07:00
Linus Torvalds 99dbb1632f Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial
Pull the trivial tree from Jiri Kosina:
 "Tiny usual fixes all over the place"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial: (34 commits)
  doc: fix old config name of kprobetrace
  fs/fs-writeback.c: cleanup riteback_sb_inodes kerneldoc
  btrfs: fix the commment for the action flags in delayed-ref.h
  btrfs: fix trivial typo for the comment of BTRFS_FREE_INO_OBJECTID
  vfs: fix kerneldoc for generic_fh_to_parent()
  treewide: fix comment/printk/variable typos
  ipr: fix small coding style issues
  doc: fix broken utf8 encoding
  nfs: comment fix
  platform/x86: fix asus_laptop.wled_type module parameter
  mfd: printk/comment fixes
  doc: getdelays.c: remember to close() socket on error in create_nl_socket()
  doc: aliasing-test: close fd on write error
  mmc: fix comment typos
  dma: fix comments
  spi: fix comment/printk typos in spi
  Coccinelle: fix typo in memdup_user.cocci
  tmiofb: missing NULL pointer checks
  tools: perf: Fix typo in tools/perf
  tools/testing: fix comment / output typos
  ...
2012-10-01 09:06:36 -07:00
Theodore Ts'o 041bbb6d36 ext4: fix mtime update in nodelalloc mode
Commits 5e8830dc85 and 41c4d25f78 introduced a regression into
v3.6-rc1 for ext4 in nodealloc mode, such that mtime updates would not
take place for files modified via mmap if the page was already in the
page cache.  This would also affect ext3 file systems mounted using
the ext4 file system driver.

The problem was that ext4_page_mkwrite() had a shortcut which would
avoid calling __block_page_mkwrite() under some circumstances, and the
above two commit transferred the responsibility of calling
file_update_time() to __block_page_mkwrite --- which woudln't get
called in some circumstances.

Since __block_page_mkwrite() only has three callers,
block_page_mkwrite(), ext4_page_mkwrite, and nilfs_page_mkwrite(), the
best way to solve this is to move the responsibility for calling
file_update_time() to its caller.

This problem was found via xfstests #215 with a file system mounted
with -o nodelalloc.

Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Reviewed-by: Jan Kara <jack@suse.cz>
Cc: KONISHI Ryusuke <konishi.ryusuke@lab.ntt.co.jp>
Cc: stable@vger.kernel.org
2012-09-30 23:04:56 -04:00
Dmitry Monakhov 6f2080e644 ext4: fix ext_remove_space for punch_hole case
Inode is allowed to have empty leaf only if it this is blockless inode.

Signed-off-by: Dmitry Monakhov <dmonakhov@openvz.org>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
2012-09-30 23:03:50 -04:00
Dmitry Monakhov 02d262dffc ext4: punch_hole should wait for DIO writers
punch_hole is the place where we have to wait for all existing writers
(writeback, aio, dio), but currently we simply flush pended end_io request
which is not sufficient. Other issue is that punch_hole performed w/o i_mutex
held which obviously result in dangerous data corruption due to
write-after-free.

This patch performs following changes:
- Guard punch_hole with i_mutex
- Recheck inode flags under i_mutex
- Block all new dio readers in order to prevent information leak caused by
  read-after-free pattern.
- punch_hole now wait for all writers in flight
  NOTE: XXX write-after-free race is still possible because new dirty pages
  may appear due to mmap(), and currently there is no easy way to stop
  writeback while punch_hole is in progress.

[ Fixed error return from ext4_ext_punch_hole() to make sure that we
  release i_mutex before returning EPERM or ETXTBUSY -- Ted ]

Signed-off-by: Dmitry Monakhov <dmonakhov@openvz.org>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
2012-09-30 23:03:42 -04:00
Dmitry Monakhov 1f555cfa29 ext4: serialize truncate with owerwrite DIO workers
Jan Kara have spotted interesting issue:
There are  potential data corruption issue with  direct IO overwrites
racing with truncate:
 Like:
  dio write                      truncate_task
  ->ext4_ext_direct_IO
   ->overwrite == 1
    ->down_read(&EXT4_I(inode)->i_data_sem);
    ->mutex_unlock(&inode->i_mutex);
                               ->ext4_setattr()
                                ->inode_dio_wait()
                                ->truncate_setsize()
                                ->ext4_truncate()
                                 ->down_write(&EXT4_I(inode)->i_data_sem);
    ->__blockdev_direct_IO
     ->ext4_get_block
     ->submit_io()
    ->up_read(&EXT4_I(inode)->i_data_sem);
                                 # truncate data blocks, allocate them to
                                 # other inode - bad stuff happens because
                                 # dio is still in flight.

In order to serialize with truncate dio worker should grab extra i_dio_count
reference before drop i_mutex.

Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Dmitry Monakhov <dmonakhov@openvz.org>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
2012-09-29 00:58:26 -04:00
Dmitry Monakhov 1b65007e98 ext4: endless truncate due to nonlocked dio readers
If we have enough aggressive DIO readers, truncate and other dio
waiters will wait forever inside inode_dio_wait(). It is reasonable
to disable nonlock DIO read optimization during truncate.

Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Dmitry Monakhov <dmonakhov@openvz.org>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
2012-09-29 00:56:15 -04:00
Dmitry Monakhov 1c9114f9c0 ext4: serialize unlocked dio reads with truncate
Current serialization will works only for DIO which holds
i_mutex, but nonlocked DIO following race is possible:

dio_nolock_read_task            truncate_task
				->ext4_setattr()
				 ->inode_dio_wait()
->ext4_ext_direct_IO
  ->ext4_ind_direct_IO
    ->__blockdev_direct_IO
      ->ext4_get_block
				 ->truncate_setsize()
				 ->ext4_truncate()
				 #alloc truncated blocks
				 #to other inode
      ->submit_io()
     #INFORMATION LEAK

In order to serialize with unlocked DIO reads we have to
rearrange wait sequence
1) update i_size first
2) if i_size about to be reduced wait for outstanding DIO requests
3) and only after that truncate inode blocks

Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Dmitry Monakhov <dmonakhov@openvz.org>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
2012-09-29 00:55:23 -04:00
Dmitry Monakhov 17335dcc47 ext4: serialize dio nonlocked reads with defrag workers
Inode's block defrag and ext4_change_inode_journal_flag() may
affect nonlocked DIO reads result, so proper synchronization
required.

- Add missed inode_dio_wait() calls where appropriate
- Check inode state under extra i_dio_count reference.

Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Dmitry Monakhov <dmonakhov@openvz.org>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
2012-09-29 00:41:21 -04:00
Dmitry Monakhov 28a535f9a0 ext4: completed_io locking cleanup
Current unwritten extent conversion state-machine is very fuzzy.
- For unknown reason it performs conversion under i_mutex. What for?
  My diagnosis:
  We already protect extent tree with i_data_sem, truncate and punch_hole
  should wait for DIO, so the only data we have to protect is end_io->flags
  modification, but only flush_completed_IO and end_io_work modified this
  flags and we can serialize them via i_completed_io_lock.

  Currently all these games with mutex_trylock result in the following deadlock
   truncate:                          kworker:
    ext4_setattr                       ext4_end_io_work
    mutex_lock(i_mutex)
    inode_dio_wait(inode)  ->BLOCK
                             DEADLOCK<- mutex_trylock()
                                        inode_dio_done()
  #TEST_CASE1_BEGIN
  MNT=/mnt_scrach
  unlink $MNT/file
  fallocate -l $((1024*1024*1024)) $MNT/file
  aio-stress -I 100000 -O -s 100m -n -t 1 -c 10 -o 2 -o 3 $MNT/file
  sleep 2
  truncate -s 0 $MNT/file
  #TEST_CASE1_END

Or use 286's xfstests https://github.com/dmonakhov/xfstests/blob/devel/286

This patch makes state machine simple and clean:

(1) xxx_end_io schedule final extent conversion simply by calling
    ext4_add_complete_io(), which append it to ei->i_completed_io_list
    NOTE1: because of (2A) work should be queued only if
    ->i_completed_io_list was empty, otherwise the work is scheduled already.

(2) ext4_flush_completed_IO is responsible for handling all pending
    end_io from ei->i_completed_io_list
    Flushing sequence consists of following stages:
    A) LOCKED: Atomically drain completed_io_list to local_list
    B) Perform extents conversion
    C) LOCKED: move converted io's to to_free list for final deletion
       	     This logic depends on context which we was called from.
    D) Final end_io context destruction
    NOTE1: i_mutex is no longer required because end_io->flags modification
    is protected by ei->ext4_complete_io_lock

Full list of changes:
- Move all completion end_io related routines to page-io.c in order to improve
  logic locality
- Move open coded logic from various xx_end_xx routines to ext4_add_complete_io()
- remove EXT4_IO_END_FSYNC
- Improve SMP scalability by removing useless i_mutex which does not
  protect io->flags anymore.
- Reduce lock contention on i_completed_io_lock by optimizing list walk.
- Rename ext4_end_io_nolock to end4_end_io and make it static
- Check flush completion status to ext4_ext_punch_hole(). Because it is
  not good idea to punch blocks from corrupted inode.

Changes since V3 (in request to Jan's comments):
  Fall back to active flush_completed_IO() approach in order to prevent
  performance issues with nolocked DIO reads.
Changes since V2:
  Fix use-after-free caused by race truncate vs end_io_work

Signed-off-by: Dmitry Monakhov <dmonakhov@openvz.org>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
2012-09-29 00:14:55 -04:00
Dmitry Monakhov 82e5422911 ext4: fix unwritten counter leakage
ext4_set_io_unwritten_flag() will increment i_unwritten counter, so
once we mark end_io with EXT4_END_IO_UNWRITTEN we have to revert it back
on error path.

 - add missed error checks to prevent counter leakage
 - ext4_end_io_nolock() will clear EXT4_END_IO_UNWRITTEN flag to signal
   that conversion finished.
 - add BUG_ON to ext4_free_end_io() to prevent similar leakage in future.

Visible effect of this bug is that unaligned aio_stress may deadlock

Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Dmitry Monakhov <dmonakhov@openvz.org>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
2012-09-28 23:36:25 -04:00
Dmitry Monakhov e27f41e1b7 ext4: give i_aiodio_unwritten a more appropriate name
AIO/DIO prefix is wrong because it account unwritten extents which
also may be scheduled from buffered write endio

Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Dmitry Monakhov <dmonakhov@openvz.org>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
2012-09-28 23:24:52 -04:00
Dmitry Monakhov f45ee3a1ea ext4: ext4_inode_info diet
Generic inode has unused i_private pointer which may be used as cur_aio_dio
storage.

TODO: If cur_aio_dio will be passed as an argument to get_block_t this allow
      to have concurent AIO_DIO requests.

Reviewed-by: Zheng Liu <wenqing.lz@taobao.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Dmitry Monakhov <dmonakhov@openvz.org>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
2012-09-28 23:21:09 -04:00
Wei Yongjun ba39ebb614 ext4: convert to use leXX_add_cpu()
Convert cpu_to_leXX(leXX_to_cpu(E1) + E2) to use leXX_add_cpu().

dpatch engine is used to auto generate this patch.
(https://github.com/weiyj/dpatch)

Signed-off-by: Wei Yongjun <yongjun_wei@trendmicro.com.cn>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
2012-09-27 09:37:53 -04:00
Carlos Maiolino 6d1ab10e69 ext4: ext4_bread usage audit
When ext4_bread() returns NULL and err is set to zero, this means
there is no phyical block mapped to the specified logical block
number.  (Previous to commit 90b0a97323, err was uninitialized in this
case, which caused other problems.)

The directory handling routines use ext4_bread() in many places, the
fact that ext4_bread() now returns NULL with err set to zero could
cause problems since a number of these functions will simply return
the value of err if the result of ext4_bread() was the NULL pointer,
causing the caller of the function to think that the function was
successful.

Since directories should never contain holes, this case can only
happen if the file system is corrupted.  This commit audits all of the
callers of ext4_bread(), and makes sure they do the right thing if a
hole in a directory is found by ext4_bread().

Some ext4_bread() callers did not need any changes either because they
already had its own hole detector paths.

Signed-off-by: Carlos Maiolino <cmaiolino@redhat.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
2012-09-27 09:31:33 -04:00
Wang Sheng-Hui cbb4ee830e ext4: remove redundant offset check in mext_check_arguments()
In the check code above, if orig_start != donor_start, we would
return -EINVAL. So here, orig_start should be equal with donor_start.
Remove the redundant check here.

Signed-off-by: Wang Sheng-Hui <shhuiw@gmail.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
2012-09-27 08:00:01 -04:00
Eric Sandeen c25f9bc614 ext4: don't clear orphan list on ro mount with errors
If the file system contains errors and it is being mounted read-only,
don't clear the orphan list.  We should minimize changes to the file
system if it is mounted read-only.

Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
2012-09-26 23:30:12 -04:00
Djalal Harouni 9b68733273 ext4: release donor reference when EXT4_IOC_MOVE_EXT ioctl fails
When the EXT4_IOC_MOVE_EXT ioctl() fails on bigalloc file systems, we
should jump to the 'mext_out' label to release the donor file reference.

Signed-off-by: Djalal Harouni <tixxdz@opendz.org>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
2012-09-26 22:58:50 -04:00
Lukas Czerner aaf7d73e54 ext4: enable FITRIM ioctl on bigalloc file system
With a minor tweaks regarding minimum extent size to discard and
discarded bytes reporting the FITRIM can be enabled on bigalloc file
system and it works without any problem.

This patch fixes minlen handling and discarded bytes reporting to
take into consideration bigalloc enabled file systems and finally
removes the restriction and allow FITRIM to be used on file system with
bigalloc feature enabled.

Reviewed-by: Carlos Maiolino <cmaiolino@redhat.com>
Signed-off-by: Lukas Czerner <lczerner@redhat.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
2012-09-26 22:21:21 -04:00
Al Viro 2903ff019b switch simple cases of fget_light to fdget
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-09-26 22:20:08 -04:00
Jan Kara b71fc079b5 ext4: fix fdatasync() for files with only i_size changes
Code tracking when transaction needs to be committed on fdatasync(2) forgets
to handle a situation when only inode's i_size is changed. Thus in such
situations fdatasync(2) doesn't force transaction with new i_size to disk
and that can result in wrong i_size after a crash.

Fix the issue by updating inode's i_datasync_tid whenever its size is
updated.

CC: <stable@vger.kernel.org> # >= 2.6.32
Reported-by: Kristian Nielsen <knielsen@knielsen-hq.org>
Signed-off-by: Jan Kara <jack@suse.cz>
2012-09-26 21:52:20 -04:00
Bernd Schubert 6a08f447fa ext4: always set i_op in ext4_mknod()
ext4_special_inode_operations have their own ifdef CONFIG_EXT4_FS_XATTR
to mask those methods. And ext4_iget also always sets it, so there is
an inconsistency.

Signed-off-by: Bernd Schubert <bernd.schubert@itwm.fraunhofer.de>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Cc: stable@vger.kernel.org
2012-09-26 21:24:57 -04:00
Al Viro 6bdf295401 switch EXT4_IOC_MOVE_EXT to fget_light()
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-09-26 21:10:06 -04:00
Al Viro 399c9b862f ext4: close struct file leak on EXT4_IOC_MOVE_EXT
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-09-26 21:10:06 -04:00
Lukas Czerner 63fedaf1c2 ext4: remove unused function ext4_ext_check_cache
Remove unused function ext4_ext_check_cache() and merge the code back to
the ext4_ext_in_cache().

Reviewed-by: Carlos Maiolino <cmaiolino@redhat.com>
Signed-off-by: Lukas Czerner <lczerner@redhat.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
2012-09-26 21:09:06 -04:00
Wei Yongjun 85556c9a50 ext4: use kmem_cache_zalloc instead of kmem_cache_alloc/memset
Using kmem_cache_zalloc() instead of kmem_cache_alloc() and memset().

spatch with a semantic match is used to found this problem.
(http://coccinelle.lip6.fr/)

Signed-off-by: Wei Yongjun <yongjun_wei@trendmicro.com.cn>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
2012-09-26 20:43:37 -04:00
Dmitry Monakhov 8c85447391 ext4: reimplement uninit extent optimization for move_extent_per_page()
Uninitialized extent may became initialized(parallel writeback task)
at any moment after we drop i_data_sem, so we have to recheck extent's
state after we hold page's lock and i_data_sem.

If we about to change page's mapping we must hold page's lock in order to
serialize other users.

Signed-off-by: Dmitry Monakhov <dmonakhov@openvz.org>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
2012-09-26 12:54:52 -04:00
Dmitry Monakhov bb55748805 ext4: clean up online defrag bugs in move_extent_per_page()
Non-full list of bugs:
1) uninitialized extent optimization does not hold page's lock,
   and simply replace brunches after that writeback code goes
   crazy because block mapping changed under it's feets
   kernel BUG at fs/ext4/inode.c:1434!  ( 288'th xfstress)

2) uninitialized extent may became initialized right after we
   drop i_data_sem, so extent state must be rechecked

3) Locked pages goes uptodate via following sequence:
   ->readpage(page); lock_page(page); use_that_page(page)
   But after readpage() one may invalidate it because it is
   uptodate and unlocked (reclaimer does that)
   As result kernel bug at include/linux/buffer_head.c:133!

4) We call write_begin() with already opened stansaction which
   result in following deadlock:
->move_extent_per_page()
  ->ext4_journal_start()-> hold journal transaction
  ->write_begin()
    ->ext4_da_write_begin()
      ->ext4_nonda_switch()
        ->writeback_inodes_sb_if_idle()  --> will wait for journal_stop()

5) try_to_release_page() may fail and it does fail if one of page's bh was
   pinned by journal

6) If we about to change page's mapping we MUST hold it's lock during entire
   remapping procedure, this is true for both pages(original and donor one)

Fixes:

- Avoid (1) and (2) simply by temproraly drop uninitialized extent handling
  optimization, this will be reimplemented later.

- Fix (3) by manually forcing page to uptodate state w/o dropping it's lock

- Fix (4) by rearranging existing locking:
  from: journal_start(); ->write_begin
  to: write_begin(); journal_extend()
- Fix (5) simply by checking retvalue
- Fix (6) by locking both (original and donor one) pages during extent swap
  with help of mext_page_double_lock()

Signed-off-by: Dmitry Monakhov <dmonakhov@openvz.org>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
2012-09-26 12:52:07 -04:00
Dmitry Monakhov f066055a34 ext4: online defrag is not supported for journaled files
Proper block swap for inodes with full journaling enabled is
truly non obvious task. In order to be on a safe side let's
explicitly disable it for now.

Signed-off-by: Dmitry Monakhov <dmonakhov@openvz.org>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Cc: stable@vger.kernel.org
2012-09-26 12:32:54 -04:00
Dmitry Monakhov 03bd8b9b89 ext4: move_extent code cleanup
- Remove usless checks, because it is too late to check that inode != NULL
  at the moment it was referenced several times.
- Double lock routines looks very ugly and locking ordering relays on
  order of i_ino, but other kernel code rely on order of pointers.
  Let's make them simple and clean.
- check that inodes belongs to the same SB as soon as possible.

Signed-off-by: Dmitry Monakhov <dmonakhov@openvz.org>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Cc: stable@vger.kernel.org
2012-09-26 12:32:19 -04:00
Tao Ma 0acdb8876f ext4: don't call update_backups() multiple times for the same bg
When performing an online resize, we add a bunch of groups at one time
in ext4_flex_group_add, so in most cases a lot of group descriptors
will be in the same group block. But in the end of this function,
update_backups will be called for every group descriptor and the same
block will be copied and journalled again and again.  It is really a
waste.

Fix things so we only update a particular bg descriptor block once and
skip subsequent updates of the same block.

Signed-off-by: Tao Ma <boyu.mt@taobao.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
2012-09-26 00:08:57 -04:00
Dmitry Monakhov 7f1468d1d5 ext4: fix double unlock buffer mess during fs-resize
bh_submit_read() is responsible for unlock bh on endio.  In addition,
we need to use bh_uptodate_or_lock() to avoid races.

Signed-off-by: Dmitry Monakhov <dmonakhov@openvz.org>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
2012-09-25 23:19:25 -04:00
Yongqiang Yang f2a09af645 ext4: check free inode count before allocating an inode
Recently, I ecountered some corrupted filesystems in which some
groups' free inode counts were 65535, it seemed that free inode
count was overflow.  This patch teaches ext4 to check free inode
count before allocaing an inode.

Signed-off-by: Yongqiang Yang <xiaoqiangnk@gmail.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
2012-09-23 23:16:03 -04:00
Yongqiang Yang 838cd0cf9a ext4: check free block counters in ext4_mb_find_by_goal
Free block counters should be checked before doing allocation.

Signed-off-by: Yongqiang Yang <xiaoqiangnk@gmail.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
2012-09-23 23:10:51 -04:00
Herton Ronaldo Krzesinski 50df9fd55e ext4: fix crash when accessing /proc/mounts concurrently
The crash was caused by a variable being erronously declared static in
token2str().

In addition to /proc/mounts, the problem can also be easily replicated
by accessing /proc/fs/ext4/<partition>/options in parallel:

$ cat /proc/fs/ext4/<partition>/options > options.txt

... and then running the following command in two different terminals:

$ while diff /proc/fs/ext4/<partition>/options options.txt; do true; done

This is also the cause of the following a crash while running xfstests
#234, as reported in the following bug reports:

	https://bugs.launchpad.net/bugs/1053019
	https://bugzilla.kernel.org/show_bug.cgi?id=47731

Signed-off-by: Herton Ronaldo Krzesinski <herton.krzesinski@canonical.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Cc: Brad Figg <brad.figg@canonical.com>
Cc: stable@vger.kernel.org
2012-09-23 22:49:12 -04:00
Tao Ma bef53b01fa ext4: remove erroneous ext4_superblock_csum_set() in update_backups()
The update_backups() function is used to backup all the metadata
blocks, so we should not take it for granted that 'data' is pointed to
a super block and use ext4_superblock_csum_set to calculate the
checksum there.  In case where the data is a group descriptor block,
it will corrupt the last group descriptor, and then e2fsck will
complain about it it.

As all the metadata checksums should already be OK when we do the
backup, remove the wrong ext4_superblock_csum_set and it should be
just fine.

Reported-by: "Theodore Ts'o" <tytso@mit.edu>
Signed-off-by: Tao Ma <boyu.mt@taobao.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Cc: stable@vger.kernel.org
2012-09-20 11:35:38 -04:00
Theodore Ts'o 00d4e7362e ext4: fix potential deadlock in ext4_nonda_switch()
In ext4_nonda_switch(), if the file system is getting full we used to
call writeback_inodes_sb_if_idle().  The problem is that we can be
holding i_mutex already, and this causes a potential deadlock when
writeback_inodes_sb_if_idle() when it tries to take s_umount.  (See
lockdep output below).

As it turns out we don't need need to hold s_umount; the fact that we
are in the middle of the write(2) system call will keep the superblock
pinned.  Unfortunately writeback_inodes_sb() checks to make sure
s_umount is taken, and the VFS uses a different mechanism for making
sure the file system doesn't get unmounted out from under us.  The
simplest way of dealing with this is to just simply grab s_umount
using a trylock, and skip kicking the writeback flusher thread in the
very unlikely case that we can't take a read lock on s_umount without
blocking.

Also, we now check the cirteria for kicking the writeback thread
before we decide to whether to fall back to non-delayed writeback, so
if there are any outstanding delayed allocation writes, we try to get
them resolved as soon as possible.

   [ INFO: possible circular locking dependency detected ]
   3.6.0-rc1-00042-gce894ca #367 Not tainted
   -------------------------------------------------------
   dd/8298 is trying to acquire lock:
    (&type->s_umount_key#18){++++..}, at: [<c02277d4>] writeback_inodes_sb_if_idle+0x28/0x46

   but task is already holding lock:
    (&sb->s_type->i_mutex_key#8){+.+...}, at: [<c01ddcce>] generic_file_aio_write+0x5f/0xd3

   which lock already depends on the new lock.

   2 locks held by dd/8298:
    #0:  (sb_writers#2){.+.+.+}, at: [<c01ddcc5>] generic_file_aio_write+0x56/0xd3
    #1:  (&sb->s_type->i_mutex_key#8){+.+...}, at: [<c01ddcce>] generic_file_aio_write+0x5f/0xd3

   stack backtrace:
   Pid: 8298, comm: dd Not tainted 3.6.0-rc1-00042-gce894ca #367
   Call Trace:
    [<c015b79c>] ? console_unlock+0x345/0x372
    [<c06d62a1>] print_circular_bug+0x190/0x19d
    [<c019906c>] __lock_acquire+0x86d/0xb6c
    [<c01999db>] ? mark_held_locks+0x5c/0x7b
    [<c0199724>] lock_acquire+0x66/0xb9
    [<c02277d4>] ? writeback_inodes_sb_if_idle+0x28/0x46
    [<c06db935>] down_read+0x28/0x58
    [<c02277d4>] ? writeback_inodes_sb_if_idle+0x28/0x46
    [<c02277d4>] writeback_inodes_sb_if_idle+0x28/0x46
    [<c026f3b2>] ext4_nonda_switch+0xe1/0xf4
    [<c0271ece>] ext4_da_write_begin+0x27/0x193
    [<c01dcdb0>] generic_file_buffered_write+0xc8/0x1bb
    [<c01ddc47>] __generic_file_aio_write+0x1dd/0x205
    [<c01ddce7>] generic_file_aio_write+0x78/0xd3
    [<c026d336>] ext4_file_write+0x480/0x4a6
    [<c0198c1d>] ? __lock_acquire+0x41e/0xb6c
    [<c0180944>] ? sched_clock_cpu+0x11a/0x13e
    [<c01967e9>] ? trace_hardirqs_off+0xb/0xd
    [<c018099f>] ? local_clock+0x37/0x4e
    [<c0209f2c>] do_sync_write+0x67/0x9d
    [<c0209ec5>] ? wait_on_retry_sync_kiocb+0x44/0x44
    [<c020a7b9>] vfs_write+0x7b/0xe6
    [<c020a9a6>] sys_write+0x3b/0x64
    [<c06dd4bd>] syscall_call+0x7/0xb

Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Cc: stable@vger.kernel.org
2012-09-19 22:42:36 -04:00
Andrey Sidorov 18888cf088 ext4: speed up truncate/unlink by not using bforget() unless needed
Do not iterate over data blocks scanning for bh's to forget as they're
never exist. This improves time taken by unlink / truncate syscall.
Tested by continuously truncating file that is being written by dd.
Another test is rm -rf of linux tree while tar unpacks it. With
ordered data mode condition unlikely(!tbh) was always met in
ext4_free_blocks. With journal data mode tbh was found only few times,
so optimisation is also possible.

Unlinking fallocated 60G file after doing sync && echo 3 >
/proc/sys/vm/drop_caches && time rm --help

X86 before (linux 3.6-rc4):
# time rm -f test1
real    0m2.710s
user    0m0.000s
sys     0m1.530s

X86 after:
# time rm -f test1
real    0m0.644s
user    0m0.003s
sys     0m0.060s

MIPS before (linux 2.6.37):
# time rm -f test1
real    0m 4.93s
user    0m 0.00s
sys     0m 4.61s

MIPS after:
# time rm -f test1
real    0m 0.16s
user    0m 0.00s
sys     0m 0.06s

Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Signed-off-by: Andrey Sidorov <qrxd43@motorola.com>
2012-09-19 14:14:53 -04:00
Theodore Ts'o 59e31c156a ext4: fix online resizing when the # of block groups is constant
Commit 1c6bd7173d introduced a regression where an online resize
operation which did not change the number of block groups would fail,
i.e:

	mke2fs -t /dev/vdc 60000
	mount /dev/vdc
	resize2fs /dev/vdc 60001

This was due to a bug in the logic regarding when to try converting
the filesystem to use meta_bg.

Also fix up a number of other minor issues with the online resizing
code: (a) Fix a sparse warning; (b) only check to make sure the device
is large enough once, instead of multiple times through the resize
loop.

Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
2012-09-19 00:55:56 -04:00
Anatol Pomozov c9b92530a7 ext4: make orphan functions be no-op in no-journal mode
Instead of checking whether the handle is valid, we check if journal
is enabled. This avoids taking the s_orphan_lock mutex in all cases
when there is no journal in use, including the error paths where
ext4_orphan_del() is called with a handle set to NULL.

Signed-off-by: Anatol Pomozov <anatol.pomozov@gmail.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
2012-09-18 13:38:59 -04:00
Theodore Ts'o b5e2368bae ext4: re-enable -o discard functionality in no-journal mode
This is a revert of commit b56ff9d397, which removed the call to
ext4_issue_discard() to fix a BUG reported because
ext4_issue_discard() was being called from inside a block group
spinlock.  As it turns out this bug had already been fixed by Lukas
Czerner in commit 53fdcf992d by the simple expedient of moving when
we call ext4_issue_discard() outside the spinlock.

So it should be safe to re-enable this functionality, which I tested
by putting an BUG_ON(in_atomic) just after the restored callsite to
ext4_issue_discard().

Addresses-Google-Bug: #6750518

Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Cc: Anatol Pomozov <anatol.pomozov@gmail.com>
2012-09-18 13:33:44 -04:00
Eric W. Biederman 4c376dcae8 userns: Convert struct dquot dq_id to be a struct kqid
Change struct dquot dq_id to a struct kqid and remove the now
unecessary dq_type.

Make minimal changes to dquot, quota_tree, quota_v1, quota_v2, ext3,
ext4, and ocfs2 to deal with the change in quota structures and
signatures.  The ocfs2 changes are larger than most because of the
extensive tracing throughout the ocfs2 quota code that prints out
dq_id.

quota_tree.c:get_index is modified to take a struct kqid instead of a
qid_t because all of it's callers pass in dquot->dq_id and it allows
me to introduce only a single conversion.

The rest of the changes are either just replacing dq_type with dq_id.type,
adding conversions to deal with the change in type and occassionally
adding qid_eq to allow quota id comparisons in a user namespace safe way.

Cc: Mark Fasheh <mfasheh@suse.com>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Jan Kara <jack@suse.cz>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andreas Dilger <adilger.kernel@dilger.ca>
Cc: Theodore Tso <tytso@mit.edu>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
2012-09-18 01:01:41 -07:00
Eric W. Biederman af84df93ff userns: Convert extN to support kuids and kgids in posix acls
Convert ext2, ext3, and ext4 to fully support the posix acl changes,
using e_uid e_gid instead e_id.

Enabled building with posix acls enabled, all filesystems supporting
user namespaces, now also support posix acls when user namespaces are enabled.

Cc: Theodore Tso <tytso@mit.edu>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andreas Dilger <adilger.kernel@dilger.ca>
Cc: Jan Kara <jack@suse.cz>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
2012-09-18 01:01:36 -07:00
Eric W. Biederman 5f3a4a28ec userns: Pass a userns parameter into posix_acl_to_xattr and posix_acl_from_xattr
- Pass the user namespace the uid and gid values in the xattr are stored
   in into posix_acl_from_xattr.

 - Pass the user namespace kuid and kgid values should be converted into
   when storing uid and gid values in an xattr in posix_acl_to_xattr.

- Modify all callers of posix_acl_from_xattr and posix_acl_to_xattr to
  pass in &init_user_ns.

In the short term this change is not strictly needed but it makes the
code clearer.  In the longer term this change is necessary to be able to
mount filesystems outside of the initial user namespace that natively
store posix acls in the linux xattr format.

Cc: Theodore Tso <tytso@mit.edu>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andreas Dilger <adilger.kernel@dilger.ca>
Cc: Jan Kara <jack@suse.cz>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
2012-09-18 01:01:35 -07:00
Carlos Maiolino 90b0a97323 ext4: fix possible non-initialized variable in htree_dirblock_to_tree()
htree_dirblock_to_tree() declares a non-initialized 'err' variable,
which is passed as a reference to another functions expecting them to
set this variable with their error codes.

It's passed to ext4_bread(), which then passes it to ext4_getblk(). If
ext4_map_blocks() returns 0 due to a lookup failure, leaving the
ext4_getblk() buffer_head uninitialized, it will make ext4_getblk()
return to ext4_bread() without initialize the 'err' variable, and
ext4_bread() will return to htree_dirblock_to_tree() with this variable
still uninitialized.  htree_dirblock_to_tree() will pass this variable
with garbage back to ext4_htree_fill_tree(), which expects a number of
directory entries added to the rb-tree. which, in case, might return a
fake non-zero value due the garbage left in the 'err' variable, leading
the kernel to an Oops in ext4_dx_readdir(), once this is expecting a
filled rb-tree node, when in turn it will have a NULL-ed one, causing an
invalid page request when trying to get a fname struct from this NULL-ed
rb-tree node in this line:

fname = rb_entry(info->curr_node, struct fname, rb_hash);

The patch itself initializes the err variable in
htree_dirblock_to_tree() to avoid usage mistakes by the called
functions, and also fix ext4_getblk() to return a initialized 'err'
variable when ext4_map_blocks() fails a lookup.

Signed-off-by: Carlos Maiolino <cmaiolino@redhat.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
2012-09-17 23:39:12 -04:00