Reduce the object size ~10% could be useful for embedded systems.

Add #ifdef CONFIG_PRINTK #else #endif blocks to hold formats and
arguments, passing " " to functions when !CONFIG_PRINTK and still
verifying format and arguments with no_printk.

$ size fs/ext4/built-in.o*
   text	   data	    bss	    dec	    hex	filename
 239375	    610	    888	 240873	  3ace9	fs/ext4/built-in.o.new
 264167	    738	    888	 265793	  40e41	fs/ext4/built-in.o.old

    $ grep -E "CONFIG_EXT4|CONFIG_PRINTK" .config
    # CONFIG_PRINTK is not set
    CONFIG_EXT4_FS=y
    CONFIG_EXT4_USE_FOR_EXT23=y
    CONFIG_EXT4_FS_POSIX_ACL=y
    # CONFIG_EXT4_FS_SECURITY is not set
    # CONFIG_EXT4_DEBUG is not set
Signed-off-by: NJoe Perches <joe@perches.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>

If memory allocation in ext4_mb_new_group_pa() is failed,
it returns error code, ext4_mb_new_preallocation() propages it,
but ext4_mb_new_blocks() ignores it.

An observed result was:

- allocation fail means ext4_mb_new_group_pa() does not update
  ext4_allocation_context;

- ext4_mb_new_blocks() sets ext4_allocation_request->len (ar->len =
  ac->ac_b_ex.fe_len;) to number of blocks preallocated (512) instead
  of number of blocks requested (1);

- that activates update cycle in ext4_splice_branch():
    for (i = 1; i < blks; i++) <-- blks is 512 instead of 1 here
      *(where->p + i) = cpu_to_le32(current_block++);

- it iterates 511 times and corrupts a chunk of memory including inode
  structure;

- page fault happens at EXT4_SB(inode->i_sb) in ext4_mark_inode_dirty();

- system hangs with 'scheduling while atomic' BUG.

The patch implements a check for ext4_mb_new_preallocation() error
code and handles its failure as if ext4_mb_regular_allocator() fails.

Found by Linux File System Verification project (linuxtesting.org).

[ Patch restructed by tytso to make the flow of control easier to follow. ]
Signed-off-by: NAlexey Khoroshilov <khoroshilov@ispras.ru>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

Subtracting the number of the first data block places the superblock
backups one block too early, corrupting the file system. When the block
size is larger than 1K, the first data block is 0, so the subtraction
has no effect and no corruption occurs.
Signed-off-by: NMaarten ter Huurne <maarten@treewalker.org>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>
Reviewed-by: NJan Kara <jack@suse.cz>
CC: stable@vger.kernel.org

This patch removed several unused variables.
Signed-off-by: NJon Ernst <jonernst07@gmx.com>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

Return the FIEMAP_EXTENT_UNKNOWN flag as well except the
FIEMAP_EXTENT_DELALLOC because the data location of an
delayed allocation extent is unknown.
Signed-off-by: NJie Liu <jeff.liu@oracle.com>

If filesystem was aborted after inode's write back is complete
but before its metadata was updated we may return success
results in data loss.
In order to handle fs abort correctly we have to check
fs state once we discover that it is in MS_RDONLY state

Test case: http://patchwork.ozlabs.org/patch/244297Reviewed-by: NJan Kara <jack@suse.cz>
Signed-off-by: NDmitry Monakhov <dmonakhov@openvz.org>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

Inode's data or non journaled quota may be written w/o jounral so we
_must_ send a barrier at the end of ext4_sync_fs. But it can be
skipped if journal commit will do it for us.

Also fix data integrity for nojournal mode.
Signed-off-by: NDmitry Monakhov <dmonakhov@openvz.org>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

Commit 18888cf0: "ext4: speed up truncate/unlink by not using
bforget() unless needed" removed the use of EXT4_FREE_BLOCKS_FORGET in
the most important codepath for file systems using extents, but a
similar optimization also can be done for file systems using indirect
blocks, and for the two special cases in the ext4 extents code.

Cc: Andrey Sidorov <qrxd43@motorola.com>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

For a file systems with a very large number of block groups, if all of
the block group bitmaps are in memory and the file system is
relatively badly fragmented, it's possible ext4_mb_regular_allocator()
to take a long time trying to find a good match.  This is especially
true if the tuning parameter mb_max_to_scan has been sent to a very
large number.  So add a cond_resched() to avoid soft lockup warnings
and to provide better system responsiveness.

For ext4_free_blocks(), if we are deleting a large range of blocks,
and data=journal is enabled so that EXT4_FREE_BLOCKS_FORGET is passed,
the loop to call sb_find_get_block() and to call ext4_forget() can
take over 10-15 milliseocnds or more.  So it's better to add a
cond_resched() here a well.
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>

The test_root() function could potentially loop forever due to
overflow issues.  So rewrite test_root() to avoid this issue; as a
bonus, it is 38% faster when benchmarked via a test loop:

int main(int argc, char **argv)
{
	int  i;

	for (i = 0; i < 1 << 24; i++) {
		if (test_root(i, 7))
			printf("%d\n", i);
	}
}
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

The group number passed to ext4_get_group_info() should be valid, but
let's add an assert to check this before we start creating a pointer
based on that group number and dereferencing it.
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

Check the group number for sanity earilier, before calling routines
such as ext4_bg_has_super() or ext4_group_overhead_blocks().
Reported-by: NJonathan Salwan <jonathan.salwan@gmail.com>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

The bio_alloc() function can return NULL if the memory allocation
fails.  So we need to check for this.
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>

We don't have to wait for unwritten extent conversion in
ext4_ind_direct_IO() as all writes that happened before DIO are
flushed by the generic code and extent conversion has happened before
we cleared PageWriteback bit.
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>

After removal of ext4_flush_unwritten_io() call, ext4_file_sync()
doesn't need i_mutex anymore. Forcing of transaction commits doesn't
need i_mutex as there's nothing inode specific in that code apart from
grabbing transaction ids from the inode. So remove the lock.
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>

Just use the generic function instead of duplicating it.  We only need
to reshuffle the read-only check a bit (which is there to prevent
writing to a filesystem which has been remounted read-only after error
I assume).
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>

Since PageWriteback bit is now cleared after extents are converted
from unwritten to written ones, we have full exclusion of writeback
path from truncate (truncate_inode_pages() waits for PageWriteback
bits to get cleared on all invalidated pages).  Exclusion from DIO
path is achieved by inode_dio_wait() call in ext4_setattr().  So
there's no need to wait for extent convertion in ext4_truncate()
anymore.
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>

Make sure extent conversion after DIO happens while i_dio_count is
still elevated so that inode_dio_wait() waits until extent conversion
is done.  This removes the need for explicit waiting for extent
conversion in some cases.
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>

Currently PageWriteback bit gets cleared from put_io_page() called
from ext4_end_bio().  This is somewhat inconvenient as extent tree is
not fully updated at that time (unwritten extents are not marked as
written) so we cannot read the data back yet.  This design was
dictated by lock ordering as we cannot start a transaction while
PageWriteback bit is set (we could easily deadlock with
ext4_da_writepages()).  But now that we use transaction reservation
for extent conversion, locking issues are solved and we can move
PageWriteback bit clearing after extent conversion is done.  As a
result we can remove wait for unwritten extent conversion from
ext4_sync_file() because it already implicitely happens through
wait_on_page_writeback().

We implement deferring of PageWriteback clearing by queueing completed
bios to appropriate io_end and processing all the pages when io_end is
going to be freed instead of at the moment ext4_io_end() is called.
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>

Now that we have extent conversions with reserved transaction, we have
to prevent extent conversions without reserved transaction (from DIO
code) to block these (as that would effectively void any transaction
reservation we did).  So split lists, work items, and work queues to
reserved and unreserved parts.
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>

Later we would like to clear PageWriteback bit only after extent
conversion from unwritten to written extents is performed.  However it
is not possible to start a transaction after PageWriteback is set
because that violates lock ordering (and is easy to deadlock).  So we
have to reserve a transaction before locking pages and sending them
for IO and later we use the transaction for extent conversion from
ext4_end_io().
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>

There isn't any need for setting BH_Uninit on buffers anymore.  It was
only used to signal we need to mark io_end as needing extent
conversion in add_bh_to_extent() but now we can mark the io_end
directly when mapping extent.
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>

There are two issues with current writeback path in ext4.  For one we
don't necessarily map complete pages when blocksize < pagesize and
thus needn't do any writeback in one iteration.  We always map some
blocks though so we will eventually finish mapping the page.  Just if
writeback races with other operations on the file, forward progress is
not really guaranteed. The second problem is that current code
structure makes it hard to associate all the bios to some range of
pages with one io_end structure so that unwritten extents can be
converted after all the bios are finished.  This will be especially
difficult later when io_end will be associated with reserved
transaction handle.

We restructure the writeback path to a relatively simple loop which
first prepares extent of pages, then maps one or more extents so that
no page is partially mapped, and once page is fully mapped it is
submitted for IO. We keep all the mapping and IO submission
information in mpage_da_data structure to somewhat reduce stack usage.
Resulting code is somewhat shorter than the old one and hopefully also
easier to read.
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 limit the number of blocks written in a single loop of
ext4_da_writepages() to 64 when inode uses indirect blocks.  That is
unnecessary as credit estimates for mapping logically continguous run
of blocks is rather low even for inode with indirect blocks.  So just
lift this limitation and properly calculate the number of necessary
credits.

This better credit estimate will also later allow us to always write
at least a single page in one iteration.
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>

ext4_ind_trans_blocks() wrongly used 'chunk' argument to decide whether
blocks mapped are logically contiguous. That is wrong since the argument
informs whether the blocks are physically contiguous. As the blocks
mapped are always logically contiguous and that's all
ext4_ind_trans_blocks() cares about, just remove the 'chunk' argument.
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>

This attribute is now unused so deprecate it.  We still show the old
default value to keep some compatibility but we don't allow writing to
that attribute anymore.
Signed-off-by: NJan Kara <jack@suse.cz>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

Writeback code got better in how it submits IO and now the number of
pages requested to be written is usually higher than original 1024.
The number is now dynamically computed based on observed throughput
and is set to be about 0.5 s worth of writeback.  E.g. on ordinary
SATA drive this ends up somewhere around 10000 as my testing shows.
So remove the unnecessary smarts from ext4_da_writepages().
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>

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>

In some cases we cannot start a transaction because of locking
constraints and passing started transaction into those places is not
handy either because we could block transaction commit for too long.
Transaction reservation is designed to solve these issues.  It
reserves a handle with given number of credits in the journal and the
handle can be later attached to the running transaction without
blocking on commit or checkpointing.  Reserved handles do not block
transaction commit in any way, they only reduce maximum size of the
running transaction (because we have to always be prepared to
accomodate request for attaching reserved handle).
Signed-off-by: NJan Kara <jack@suse.cz>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

Change writeback path to create just one io_end structure for the
extent to which we submit IO and share it among bios writing that
extent. This prevents needless splitting and joining of unwritten
extents when they cannot be submitted as a single bio.

Bugs in ENOMEM handling found by Linux File System Verification project
(linuxtesting.org) and fixed by Alexey Khoroshilov
<khoroshilov@ispras.ru>.

CC: Alexey Khoroshilov <khoroshilov@ispras.ru>
Signed-off-by: NJan Kara <jack@suse.cz>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

The arithmetics adding delalloc blocks to the number of used blocks in
ext4_getattr() can easily overflow on 32-bit archs as we first multiply
number of blocks by blocksize and then divide back by 512. Make the
arithmetics more clever and also use proper type (unsigned long long
instead of unsigned long).
Signed-off-by: NJan Kara <jack@suse.cz>
Signed-off-by: NTheodore Ts'o <tytso@mit.edu>

On 32-bit architectures with 32-bit sector_t computation of data offset
in ext4_xattr_fiemap() can overflow resulting in reporting bogus data
location. Fix the problem by typing block number to proper type before
shifting.
Signed-off-by: NJan Kara <jack@suse.cz>
Signed-off-by: NTheodore Ts'o <tytso@mit.edu>

ext4_lblk_t is just u32 so multiplying it by blocksize can easily
overflow for files larger than 4 GB. Fix that by properly typing the
block offsets before shifting.
Signed-off-by: NJan Kara <jack@suse.cz>
Signed-off-by: NTheodore Ts'o <tytso@mit.edu>
Reviewed-by: NZheng Liu <wenqing.lz@taobao.com>

On 32-bit archs when sector_t is defined as 32-bit the logic computing
data offset in ext4_inline_data_fiemap(). Fix that by properly typing
the shifted value.
Signed-off-by: NJan Kara <jack@suse.cz>
Signed-off-by: NTheodore Ts'o <tytso@mit.edu>

Suppress the messages releating to processing the ext4 orphan list
("truncating inode" and "deleting unreferenced inode") unless the
debug option is on, since otherwise they end up taking up space in the
log that could be used for more useful information.

Tested by opening several files, unlinking them, then
crashing the system, rebooting the system and examining
/var/log/messages.

Addresses the problem described in http://crbug.com/220976Signed-off-by: NPaul Taysom <taysom@chromium.org>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

Currently punch hole is disabled in file systems with bigalloc
feature enabled. However the recent changes in punch hole patch should
make it easier to support punching holes on bigalloc enabled file
systems.

This commit changes partial_cluster handling in ext4_remove_blocks(),
ext4_ext_rm_leaf() and ext4_ext_remove_space(). Currently
partial_cluster is unsigned long long type and it makes sure that we
will free the partial cluster if all extents has been released from that
cluster. However it has been specifically designed only for truncate.

With punch hole we can be freeing just some extents in the cluster
leaving the rest untouched. So we have to make sure that we will notice
cluster which still has some extents. To do this I've changed
partial_cluster to be signed long long type. The only scenario where
this could be a problem is when cluster_size == block size, however in
that case there would not be any partial clusters so we're safe. For
bigger clusters the signed type is enough. Now we use the negative value
in partial_cluster to mark such cluster used, hence we know that we must
not free it even if all other extents has been freed from such cluster.

This scenario can be described in simple diagram:

|FFF...FF..FF.UUU|
 ^----------^
  punch hole

. - free space
| - cluster boundary
F - freed extent
U - used extent

Also update respective tracepoints to use signed long long type for
partial_cluster.
Signed-off-by: NLukas Czerner <lczerner@redhat.com>
Reviewed-by: NJan Kara <jack@suse.cz>
Signed-off-by: NTheodore Ts'o <tytso@mit.edu>