linux-toradex.git/fs/ext4, branch v2.6.27.57

ext4: Implement range_cyclic in ext4_da_writepages instead of write_cache_pages

2010-07-05T18:08:46+00:00

commit 2acf2c261b823d9d9ed954f348b97620297a36b5 upstream.

With delayed allocation we lock the page in write_cache_pages() and
try to build an in memory extent of contiguous blocks.  This is needed
so that we can get large contiguous blocks request.  If range_cyclic
mode is enabled, write_cache_pages() will loop back to the 0 index if
no I/O has been done yet, and try to start writing from the beginning
of the range.  That causes an attempt to take the page lock of lower
index page while holding the page lock of higher index page, which can
cause a dead lock with another writeback thread.

The solution is to implement the range_cyclic behavior in
ext4_da_writepages() instead.

http://bugzilla.kernel.org/show_bug.cgi?id=12579

Signed-off-by: Aneesh Kumar K.V 
Signed-off-by: "Theodore Ts'o" 
Signed-off-by: Jayson R. King 
Signed-off-by: Greg Kroah-Hartman

ext4: Fix file fragmentation during large file write.

2010-07-05T18:08:45+00:00

commit 22208dedbd7626e5fc4339c417f8d24cc21f79d7 upstream.

The range_cyclic writeback mode uses the address_space writeback_index
as the start index for writeback.  With delayed allocation we were
updating writeback_index wrongly resulting in highly fragmented file.
This patch reduces the number of extents reduced from 4000 to 27 for a
3GB file.

Signed-off-by: Aneesh Kumar K.V 
Signed-off-by: Theodore Ts'o 
[dev@jaysonking.com: Some changed lines from the original version of this patch were dropped, since they were rolled up with another cherry-picked patch applied to 2.6.27.y earlier.]
[dev@jaysonking.com: Use of wbc->no_nrwrite_index_update was dropped, since write_cache_pages_da() implies it.]
Signed-off-by: Jayson R. King 
Signed-off-by: Greg Kroah-Hartman

ext4: Use our own write_cache_pages()

2010-07-05T18:08:45+00:00

commit 8e48dcfbd7c0892b4cfd064d682cc4c95a29df32 upstream.

Make a copy of write_cache_pages() for the benefit of
ext4_da_writepages().  This allows us to simplify the code some, and
will allow us to further customize the code in future patches.

There are some nasty hacks in write_cache_pages(), which Linus has
(correctly) characterized as vile.  I've just copied it into
write_cache_pages_da(), without trying to clean those bits up lest I
break something in the ext4's delalloc implementation, which is a bit
fragile right now.  This will allow Dave Chinner to clean up
write_cache_pages() in mm/page-writeback.c, without worrying about
breaking ext4.  Eventually write_cache_pages_da() will go away when I
rewrite ext4's delayed allocation and create a general
ext4_writepages() which is used for all of ext4's writeback.  Until
now this is the lowest risk way to clean up the core
write_cache_pages() function.

Signed-off-by: "Theodore Ts'o" 
Cc: Dave Chinner 
[dev@jaysonking.com: Dropped the hunks which reverted the use of no_nrwrite_index_update, since those lines weren't ever created on 2.6.27.y]
[dev@jaysonking.com: Copied from 2.6.27.y's version of write_cache_pages(), plus the changes to it from patch "vfs: Add no_nrwrite_index_update writeback control flag"]
Signed-off-by: Jayson R. King 
Signed-off-by: Greg Kroah-Hartman

ext4: check s_log_groups_per_flex in online resize code

2010-07-05T18:08:45+00:00

commit 42007efd569f1cf3bfb9a61da60ef6c2179508ca upstream.

If groups_per_flex < 2, sbi->s_flex_groups[] doesn't get filled out,
and every other access to this first tests s_log_groups_per_flex;
same thing needs to happen in resize or we'll wander off into
a null pointer when doing an online resize of the file system.

Thanks to Christoph Biedl, who came up with the trivial testcase:

# truncate --size 128M fsfile
# mkfs.ext3 -F fsfile
# tune2fs -O extents,uninit_bg,dir_index,flex_bg,huge_file,dir_nlink,extra_isize fsfile
# e2fsck -yDf -C0 fsfile
# truncate --size 132M fsfile
# losetup /dev/loop0 fsfile
# mount /dev/loop0 mnt
# resize2fs -p /dev/loop0

	https://bugzilla.kernel.org/show_bug.cgi?id=13549

Reported-by: Alessandro Polverini 
Test-case-by: Christoph Biedl  
Signed-off-by: Eric Sandeen 
Signed-off-by: "Theodore Ts'o" 
Signed-off-by: Greg Kroah-Hartman

ext4: Use tag dirty lookup during mpage_da_submit_io

2010-05-26T21:27:06+00:00

commit af6f029d3836eb7264cd3fbb13a6baf0e5fdb5ea upstream.

This enables us to drop the range_cont writeback mode
use from ext4_da_writepages.

Signed-off-by: Aneesh Kumar K.V 
Signed-off-by: Jayson R. King 
Signed-off-by: Theodore Ts'o 
Signed-off-by: Greg Kroah-Hartman

ext4: Retry block allocation if we have free blocks left

2010-05-26T21:27:06+00:00

commit df22291ff0fde0d350cf15dac3e5cc33ac528875 upstream.

When we truncate files, the meta-data blocks released are not reused
untill we commit the truncate transaction.  That means delayed get_block
request will return ENOSPC even if we have free blocks left.  Force a
journal commit and retry block allocation if we get ENOSPC with free
blocks left.

Signed-off-by: Aneesh Kumar K.V 
Signed-off-by: Mingming Cao 
Signed-off-by: "Theodore Ts'o" 
Signed-off-by: Jayson R. King 
Signed-off-by: Theodore Ts'o 
Signed-off-by: Greg Kroah-Hartman

ext4: Retry block reservation

2010-05-26T21:27:06+00:00

commit 030ba6bc67b4f2bc5cd174f57785a1745c929abe upstream.

During block reservation if we don't have enough blocks left, retry
block reservation with smaller block counts.  This makes sure we try
fallocate and DIO with smaller request size and don't fail early.  The
delayed allocation reservation cannot try with smaller block count. So
retry block reservation to handle temporary disk full conditions.  Also
print free blocks details if we fail block allocation during writepages.

Signed-off-by: Aneesh Kumar K.V 
Signed-off-by: Mingming Cao 
Signed-off-by: "Theodore Ts'o" 
Signed-off-by: Jayson R. King 
Signed-off-by: Theodore Ts'o 
Signed-off-by: Greg Kroah-Hartman

ext4: Add percpu dirty block accounting.

2010-05-26T21:27:06+00:00

commit 6bc6e63fcd7dac9e633ea29f1fddd9580ab28f3f upstream.

This patch adds dirty block accounting using percpu_counters.  Delayed
allocation block reservation is now done by updating dirty block
counter.  In a later patch we switch to non delalloc mode if the
filesystem free blocks is greater than 150% of total filesystem dirty
blocks

Signed-off-by: Aneesh Kumar K.V 
Signed-off-by: Mingming Cao
Signed-off-by: "Theodore Ts'o" 
Signed-off-by: Jayson R. King 
Signed-off-by: Theodore Ts'o 
Signed-off-by: Greg Kroah-Hartman

ext4: Make sure all the block allocation paths reserve blocks

2010-05-26T21:27:05+00:00

commit a30d542a0035b886ffaafd0057ced0a2b28c3a4f upstream.

With delayed allocation we need to make sure block are reserved before
we attempt to allocate them. Otherwise we get block allocation failure
(ENOSPC) during writepages which cannot be handled. This would mean
silent data loss (We do a printk stating data will be lost). This patch
updates the DIO and fallocate code path to do block reservation before
block allocation. This is needed to make sure parallel DIO and fallocate
request doesn't take block out of delayed reserve space.

When free blocks count go below a threshold we switch to a slow patch
which looks at other CPU's accumulated percpu counter values.

Signed-off-by: Aneesh Kumar K.V 
Signed-off-by: "Theodore Ts'o" 
Signed-off-by: Jayson R. King 
Signed-off-by: Theodore Ts'o 
Signed-off-by: Greg Kroah-Hartman

percpu counter: clean up percpu_counter_sum_and_set()

2010-05-26T21:27:05+00:00

commit 1f7c14c62ce63805f9574664a6c6de3633d4a354 upstream.

percpu_counter_sum_and_set() and percpu_counter_sum() is the same except
the former updates the global counter after accounting.  Since we are
taking the fbc->lock to calculate the precise value of the counter in
percpu_counter_sum() anyway, it should simply set fbc->count too, as the
percpu_counter_sum_and_set() does.

This patch merges these two interfaces into one.

Signed-off-by: Mingming Cao 
Acked-by: Peter Zijlstra 
Cc: 
Signed-off-by: Andrew Morton 
Signed-off-by: "Theodore Ts'o" 
Signed-off-by: Jayson R. King 
Signed-off-by: Theodore Ts'o