Set a in-memory superblock flag to indicate whether the file system is
designed to support the Hurd.

Also, add a sanity check to make sure the 64-bit feature is not set
for Hurd file systems, since i_file_acl_high conflicts with a
Hurd-specific field.
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

The Hurd file system uses uses the inode field which is now used for
i_version for its translator block.  This means that ext2 file systems
that are formatted for GNU Hurd can't be used to support NFSv4.  Given
that Hurd file systems don't support extents, and a huge number of
modern file system features, this is no great loss.

If we don't do this, the attempt to update the i_version field will
stomp over the translator block field, which will cause file system
corruption for Hurd file systems.  This can be replicated via:

mke2fs -t ext2 -o hurd /dev/vdc
mount -t ext4 /dev/vdc /vdc
touch /vdc/bug0000
umount /dev/vdc
e2fsck -f /dev/vdc

Addresses-Debian-Bug: #738758
Reported-By: NGabriele Giacone <1o5g4r8o@gmail.com>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

Introduce new FALLOC_FL_ZERO_RANGE flag for fallocate. This has the same
functionality as xfs ioctl XFS_IOC_ZERO_RANGE.

It can be used to convert a range of file to zeros preferably without
issuing data IO. Blocks should be preallocated for the regions that span
holes in the file, and the entire range is preferable converted to
unwritten extents

This can be also used to preallocate blocks past EOF in the same way as
with fallocate. Flag FALLOC_FL_KEEP_SIZE which should cause the inode
size to remain the same.

Also add appropriate tracepoints.
Signed-off-by: NLukas Czerner <lczerner@redhat.com>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

When doing filesystem wide sync, there's no need to force transaction
commit (or synchronously write inode buffer) separately for each inode
because ext4_sync_fs() takes care of forcing commit at the end (VFS
takes care of flushing buffer cache, respectively). Most of the time
this slowness doesn't manifest because previous WB_SYNC_NONE writeback
doesn't leave much to write but when there are processes aggressively
creating new files and several filesystems to sync, the sync slowness
can be noticeable. In the following test script sync(1) takes around 6
minutes when there are two ext4 filesystems mounted on a standard SATA
drive. After this patch sync takes a couple of seconds so we have about
two orders of magnitude improvement.

      function run_writers
      {
        for (( i = 0; i < 10; i++ )); do
          mkdir $1/dir$i
          for (( j = 0; j < 40000; j++ )); do
            dd if=/dev/zero of=$1/dir$i/$j bs=4k count=4 &>/dev/null
          done &
        done
      }

      for dir in "$@"; do
        run_writers $dir
      done

      sleep 40
      time sync
Signed-off-by: NJan Kara <jack@suse.cz>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

While handling punch-hole fallocate, it's useless to truncate page cache
before removing the range from extent tree (or block map in indirect case)
because page cache can be re-populated (by read-ahead or read(2) or mmap-ed
read) immediately after truncating page cache, but before updating extent
tree (or block map). In that case the user will see stale data even after
fallocate is completed.

Until the problem of data corruption resulting from pages backed by
already freed blocks is fully resolved, the simple thing we can do now
is to add another truncation of pagecache after punch hole is done.
Signed-off-by: NMaxim Patlasov <mpatlasov@parallels.com>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>
Reviewed-by: NJan Kara <jack@suse.cz>

The ext4_map_blocks() function returns the number of blocks which
satisfying the caller's request.  This number of blocks requested by
the caller is specified by an unsigned integer, but the return value
of ext4_map_blocks() is a signed integer (to accomodate error codes
per the kernel's standard error signalling convention).

Historically, overflows could never happen since mballoc() will refuse
to allocate more than 2048 blocks at a time (which is something we
should fix), and if the blocks were already allocated, the fact that
there would be some number of intervening metadata blocks pretty much
guaranteed that there could never be a contiguous region of data
blocks that was greater than 2**31 blocks.

However, this is now possible if there is a file system which is a bit
bigger than 8TB, and is created using the new mke2fs hugeblock
feature, which can create a perfectly contiguous file.  In that case,
if a userspace program attempted to call fallocate() on this already
fully allocated file, it's possible that ext4_map_blocks() could
return a number large enough that it would overflow a signed integer,
resulting in a ext4 thinking that the ext4_map_blocks() call had
failed with some strange error code.

Since ext4_map_blocks() is always free to return a smaller number of
blocks than what was requested by the caller, fix this by capping the
number of blocks that ext4_map_blocks() will ever try to map to 2**31
- 1.  In practice this should never get hit, except by someone
deliberately trying to provke the above-described bug.

Thanks to the PaX team for asking whethre this could possibly happen
in some off-line discussions about using some static code checking
technology they are developing to find bugs in kernel code.
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NJan Kara <jack@suse.cz>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

This is harmless, since ext4_walk_page_buffers only passes the handle
onto the callback function, and in this call site the function in
question, bput_one(), doesn't actually use the handle.  But there's no
point passing in an invalid handle, and it creates a Coverity warning,
so let's just clean it up.

Addresses-Coverity-Id: #1091168
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

Can be reproduced by xfstests 62 with bigalloc and 128bit size inode.
Signed-off-by: NYongqiang Yang <yangyongqiang01@baidu.com>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>
Reviewed-by: NCarlos Maiolino <cmaiolino@redhat.com>

After applied this commit (d23142c6), ext4 has supported punch hole for
a file system with bigalloc feature.  But we forgot to enable it.  This
commit fixes it.

Cc: Lukas Czerner <lczerner@redhat.com>
Signed-off-by: NZheng Liu <wenqing.lz@taobao.com>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

Akira-san has been reporting rare deadlocks of his machine when running
xfstests test 269 on ext4 filesystem. The problem turned out to be in
ext4_da_reserve_metadata() and ext4_da_reserve_space() which called
ext4_should_retry_alloc() while holding i_data_sem. Since
ext4_should_retry_alloc() can force a transaction commit, this is a
lock ordering violation and leads to deadlocks.

Fix the problem by just removing the retry loops. These functions should
just report ENOSPC to the caller (e.g. ext4_da_write_begin()) and that
function must take care of retrying after dropping all necessary locks.
Reported-and-tested-by: NAkira Fujita <a-fujita@rs.jp.nec.com>
Reviewed-by: NZheng Liu <wenqing.lz@taobao.com>
Signed-off-by: NJan Kara <jack@suse.cz>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>
Cc: stable@vger.kernel.org

Currently notify_change directly updates i_version for size updates,
which not only is counter to how all other fields are updated through
struct iattr, but also breaks XFS, which need inode updates to happen
under its own lock, and synchronized to the structure that gets written
to the log.

Remove the update in the common code, and it to btrfs and ext4,
XFS already does a proper updaste internally and currently gets a
double update with the existing code.

IMHO this is 3.13 and -stable material and should go in through the XFS
tree.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NAndreas Dilger <adilger@dilger.ca>
Acked-by: NJan Kara <jack@suse.cz>
Reviewed-by: NDave Chinner <dchinner@redhat.com>
Signed-off-by: NChris Mason <clm@fb.com>
Signed-off-by: NBen Myers <bpm@sgi.com>

Return a non-zero st_blocks to userspace for statfs() and friends.
Some versions of tar will assume that files with st_blocks == 0
do not contain any data and will skip reading them entirely.
Signed-off-by: NAndreas Dilger <andreas.dilger@intel.com>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

Pair the two trace events to make troubeshooting writepages
easier, and it should be more convinient to write a simple script
to parse the traces.

Cc: linux-ext4@vger.kernel.org
Cc: Jan Kara <jack@suse.cz>
Signed-off-by: NMing Lei <ming.lei@canonical.com>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

Commit 4e7ea81d(ext4: restructure writeback path) introduces another
performance regression on random write:

- one more page may be added to ext4 extent in
  mpage_prepare_extent_to_map, and will be submitted for I/O so
  nr_to_write will become -1 before 'done' is set

- the worse thing is that dirty pages may still be retrieved from page
  cache after nr_to_write becomes negative, so lots of small chunks
  can be submitted to block device when page writeback is catching up
  with write path, and performance is hurted.

On one arm A15 board with sata 3.0 SSD(CPU: 1.5GHz dura core, RAM:
2GB, SATA controller: 3.0Gbps), this patch can improve below test's
result from 157MB/sec to 174MB/sec(>10%):

	dd if=/dev/zero of=./z.img bs=8K count=512K

The above test is actually prototype of block write in bonnie++
utility.

This patch makes sure no more pages than nr_to_write can be added to
extent for mapping, so that nr_to_write won't become negative.

Cc: linux-ext4@vger.kernel.org
Acked-by: NJan Kara <jack@suse.cz>
Signed-off-by: NMing Lei <ming.lei@canonical.com>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

Document give_up_on_write argument of mpage_map_and_submit_extent().
Signed-off-by: NJan Kara <jack@suse.cz>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

The Linux Kernel Performance project guys have reported that commit
4e7ea81d introduces a performance regression for the following fio
workload:

[global]
direct=0
ioengine=mmap
size=1500M
bs=4k
pre_read=1
numjobs=1
overwrite=1
loops=5
runtime=300
group_reporting
invalidate=0
directory=/mnt/
file_service_type=random:36
file_service_type=random:36

[job0]
startdelay=0
rw=randrw
filename=data0/f1:data0/f2

[job1]
startdelay=0
rw=randrw
filename=data0/f2:data0/f1
...

[job7]
startdelay=0
rw=randrw
filename=data0/f2:data0/f1

The culprit of the problem is that after the commit ext4_writepages()
are more aggressive in writing back pages. Thus we have less consecutive
dirty pages resulting in more seeking.

This increased aggressivity is caused by a bug in the condition
terminating ext4_writepages(). We start writing from the beginning of
the file even if we should have terminated ext4_writepages() because
wbc->nr_to_write <= 0.

After fixing the condition the throughput of the fio workload is about 20%
better than before writeback reorganization.
Reported-by: N"Yan, Zheng" <zheng.z.yan@intel.com>
Signed-off-by: NJan Kara <jack@suse.cz>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

truncate_pagecache() doesn't care about old size since commit
cedabed4 ("vfs: Fix vmtruncate() regression").  Let's drop it.
Signed-off-by: NKirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Add support to the core direct-io code to defer AIO completions to user
context using a workqueue.  This replaces opencoded and less efficient
code in XFS and ext4 (we save a memory allocation for each direct IO)
and will be needed to properly support O_(D)SYNC for AIO.

The communication between the filesystem and the direct I/O code requires
a new buffer head flag, which is a bit ugly but not avoidable until the
direct I/O code stops abusing the buffer_head structure for communicating
with the filesystems.

Currently this creates a per-superblock unbound workqueue for these
completions, which is taken from an earlier patch by Jan Kara.  I'm
not really convinced about this use and would prefer a "normal" global
workqueue with a high concurrency limit, but this needs further discussion.

JK: Fixed ext4 part, dynamic allocation of the workqueue.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJan Kara <jack@suse.cz>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Signed-off-by: NAnatol Pomozov <anatol.pomozov@gmail.com>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

Use wait_for_stable_page() instead of wait_on_page_writeback()
Signed-off-by: NDmitry Monakhov <dmonakhov@openvz.org>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>
Reviewed-by: NJan Kara <jack@suse.cz>

The following race can lead to a loss of i_disksize update from truncate
thus resulting in a wrong inode size if the inode size isn't updated
again before inode is reclaimed:

ext4_setattr()				mpage_map_and_submit_extent()
  EXT4_I(inode)->i_disksize = attr->ia_size;
  ...					  ...
					  disksize = ((loff_t)mpd->first_page) << PAGE_CACHE_SHIFT
					  /* False because i_size isn't
					   * updated yet */
					  if (disksize > i_size_read(inode))
					  /* True, because i_disksize is
					   * already truncated */
					  if (disksize > EXT4_I(inode)->i_disksize)
					    /* Overwrite i_disksize
					     * update from truncate */
					    ext4_update_i_disksize()
  i_size_write(inode, attr->ia_size);

For other places updating i_disksize such race cannot happen because
i_mutex prevents these races. Writeback is the only place where we do
not hold i_mutex and we cannot grab it there because of lock ordering.

We fix the race by doing both i_disksize and i_size update in truncate
atomically under i_data_sem and in mpage_map_and_submit_extent() we move
the check against i_size under i_data_sem as well.
Signed-off-by: NJan Kara <jack@suse.cz>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>
Cc: stable@vger.kernel.org

Merge conditions in ext4_setattr() handling inode size changes, also
move ext4_begin_ordered_truncate() call somewhat earlier because it
simplifies error recovery in case of failure. Also add error handling in
case i_disksize update fails.
Signed-off-by: NJan Kara <jack@suse.cz>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>
Cc: stable@vger.kernel.org

Inode size can arbitrarily change while writeback is in progress. When
ext4_writepages() has prepared a long extent for mapping and truncate
then reduces i_size, mpage_map_and_submit_buffers() will always map just
one buffer in a page instead of all of them due to lblk < blocks check.
So we end up not using all blocks we've allocated (thus leaking them)
and also delalloc accounting goes wrong manifesting as a warning like:

ext4_da_release_space:1333: ext4_da_release_space: ino 12, to_free 1
with only 0 reserved data blocks

Note that the problem can happen only when blocksize < pagesize because
otherwise we have only a single buffer in the page.

Fix the problem by removing the size check from the mapping loop. We
have an extent allocated so we have to use it all before checking for
i_size. We also rename add_page_bufs_to_extent() to
mpage_process_page_bufs() and make that function submit the page for IO
if all buffers (upto EOF) in it are mapped.
Reported-by: NDave Jones <davej@redhat.com>
Reported-by: NZheng Liu <gnehzuil.liu@gmail.com>
Signed-off-by: NJan Kara <jack@suse.cz>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>
Cc: stable@vger.kernel.org

Currently the logic whether the current buffer can be added to an extent
of buffers to map is split between mpage_add_bh_to_extent() and
add_page_bufs_to_extent(). Move the whole logic to
mpage_add_bh_to_extent() which makes things a bit more straightforward
and make following i_size fixes easier.
Signed-off-by: NJan Kara <jack@suse.cz>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>
Cc: stable@vger.kernel.org

Don't use an unsigned long long for the es_status flags; this requires
that we pass 64-bit values around which is painful on 32-bit systems.
Instead pass the extent status flags around using the low 4 bits of an
unsigned int, and shift them into place when we are reading or writing
es_pblk.
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>
Reviewed-by: NZheng Liu <wenqing.lz@taobao.com>

Commit 0713ed0c added
jbd2_journal_file_inode() call into ext4_block_zero_page_range().
However that function gets called from truncate path and thus inode
needn't have jinode attached - that happens in ext4_file_open() but
the file needn't be ever open since mount. Calling
jbd2_journal_file_inode() without jinode attached results in the oops.

We fix the problem by attaching jinode to inode also in ext4_truncate()
and ext4_punch_hole() when we are going to zero out partial blocks.
Reported-by: Nmajianpeng <majianpeng@gmail.com>
Signed-off-by: NJan Kara <jack@suse.cz>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

In commit 921f266b: ext4: add self-testing infrastructure to do a
sanity check, some sanity checks were added in map_blocks to make sure
'retval == map->m_len'.

Enable these checks by default and report any assertion failures using
ext4_warning() and WARN_ON() since they can help us to figure out some
bugs that are otherwise hard to hit.
Signed-off-by: NZheng Liu <wenqing.lz@taobao.com>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

If there are no items in the extent status tree, ext4_es_lru_add() is
a no-op.  So it is not sufficient to call ext4_es_lru_add() before we
try to lookup an entry in the extent status tree.  We also need to
call it at the end of ext4_ext_map_blocks(), after items have been
added to the extent status tree.

This could lead to inodes with that have extent status trees but which
are not in the LRU list, which means they won't get considered for
eviction by the es_shrinker.
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>
Cc: Zheng Liu <wenqing.lz@taobao.com>
Cc: stable@vger.kernel.org

Replace "assertation" with "assertion" in lots and lots of debugging
messages.

Correct the comment stating when ext4_es_insert_extent() is used.  It
was no doubt tree at one point, but it is no longer true...
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>
Cc: Zheng Liu <gnehzuil.liu@gmail.com>

The loop in mpage_map_and_submit_extent() is guaranteed to always run
at least once since the caller of mpage_map_and_submit_extent() makes
sure map->m_len > 0. So make that explicit using do-while instead of
pure while which also silences the compiler warning about
uninitialized 'err' variable.
Signed-off-by: NJan Kara <jack@suse.cz>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>
Reviewed-by: NLukas Czerner <lczerner@redhat.com>

The function mpage_released_unused_page() must only be called once;
otherwise the kernel will BUG() when the second call to
mpage_released_unused_page() tries to unlock the pages which had been
unlocked by the first call.

Also restructure the error handling so that we only give up on writing
the dirty pages in the case of ENOSPC where retrying the allocation
won't help.  Otherwise, a transient failure, such as a kmalloc()
failure in calling ext4_map_blocks() might cause us to give up on
those pages, leading to a scary message in /var/log/messages plus data
loss.
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>
Reviewed-by: NJan Kara <jack@suse.cz>

Currently if we pass range into ext4_zero_partial_blocks() which covers
entire block we would attempt to zero it even though we should only zero
unaligned part of the block.

Fix this by checking whether the range covers the whole block skip
zeroing if so.
Signed-off-by: NLukas Czerner <lczerner@redhat.com>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

The function ext4_write_inline_data_end() can return an error.  So we
need to assign it to a signed integer variable to check for an error
return (since copied is an unsigned int).
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>
Cc: Zheng Liu <wenqing.lz@taobao.com>
Cc: stable@vger.kernel.org

Comparing unsigned variable with 0 always returns false.
err = 0 is duplicated and unnecessary.

[ tytso: Also cleaned up error handling in ext4_block_zero_page_range() ]
Signed-off-by: N"Jon Ernst" <jonernst07@gmx.com>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

No need to pass file pointer when we can directly pass inode pointer.
Signed-off-by: NAshish Sangwan <a.sangwan@samsung.com>
Signed-off-by: NNamjae Jeon <namjae.jeon@samsung.com>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

Now we maintain an proper in-order LRU list in ext4 to reclaim entries
from extent status tree when we are under heavy memory pressure.  For
keeping this order, a spin lock is used to protect this list.  But this
lock burns a lot of CPU time.  We can use the following steps to trigger
it.

  % cd /dev/shm
  % dd if=/dev/zero of=ext4-img bs=1M count=2k
  % mkfs.ext4 ext4-img
  % mount -t ext4 -o loop ext4-img /mnt
  % cd /mnt
  % for ((i=0;i<160;i++)); do truncate -s 64g $i; done
  % for ((i=0;i<160;i++)); do cp $i /dev/null &; done
  % perf record -a -g
  % perf report

This commit tries to fix this problem.  Now a new member called
i_touch_when is added into ext4_inode_info to record the last access
time for an inode.  Meanwhile we never need to keep a proper in-order
LRU list.  So this can avoid to burns some CPU time.  When we try to
reclaim some entries from extent status tree, we use list_sort() to get
a proper in-order list.  Then we traverse this list to discard some
entries.  In ext4_sb_info, we use s_es_last_sorted to record the last
time of sorting this list.  When we traverse the list, we skip the inode
that is newer than this time, and move this inode to the tail of LRU
list.  When the head of the list is newer than s_es_last_sorted, we will
sort the LRU list again.

In this commit, we break the loop if s_extent_cache_cnt == 0 because
that means that all extents in extent status tree have been reclaimed.

Meanwhile in this commit, ext4_es_{un}register_shrinker()'s prototype is
changed to save a local variable in these functions.
Reported-by: NDave Hansen <dave.hansen@intel.com>
Signed-off-by: NZheng Liu <wenqing.lz@taobao.com>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

Rename ext4_da_writepages() to ext4_writepages() and use it for all
modes.  We still need to iterate over all the pages in the case of
data=journalling, but in the case of nodelalloc/data=ordered (which is
what file systems mounted using ext3 backwards compatibility will use)
this will allow us to use a much more efficient I/O submission path.
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

Now that we clear PageWriteback after extent conversion, there's no
need to wait for io_end processing in ext4_evict_inode().  Running
AIO/DIO keeps file reference until aio_complete() is called so
ext4_evict_inode() cannot be called.  For io_end structures resulting
from buffered IO waiting is happening because we wait for
PageWriteback in truncate_inode_pages().
Reviewed-by: NZheng Liu <wenqing.lz@taobao.com>
Signed-off-by: NJan Kara <jack@suse.cz>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

We don't have to wait for extent conversion in ext4_punch_hole() as
buffered IO for the punched range has been flushed and waited upon
(thus all extent conversions for that range have completed).  Also we
wait for all DIO to finish using inode_dio_wait() so there cannot be
any extent conversions pending due to direct IO.

Also remove ext4_flush_unwritten_io() since it's unused now.
Reviewed-by: NZheng Liu <wenqing.lz@taobao.com>
Signed-off-by: NJan Kara <jack@suse.cz>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>