Commit graph

59 commits

Author SHA1 Message Date
Chris Mason
dcbdd4dcb9 Btrfs: delete checksum items before marking blocks free
Btrfs maintains a cache of blocks available for allocation in ram.  The
code that frees extents was marking the extents free and then deleting
the checksum items.

This meant it was possible the extent would be reallocated before the
checksum item was actually deleted, leading to races and other
problems as the checksums were updated for the newly allocated extent.

The fix is to delete the checksum before marking the extent free.

Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-12-16 13:51:01 -05:00
Yan Zheng
17d217fe97 Btrfs: fix nodatasum handling in balancing code
Checksums on data can be disabled by mount option, so it's
possible some data extents don't have checksums or have
invalid checksums. This causes trouble for data relocation.
This patch contains following things to make data relocation
work.

1) make nodatasum/nodatacow mount option only affects new
files. Checksums and COW on data are only controlled by the
inode flags.

2) check the existence of checksum in the nodatacow checker.
If checksums exist, force COW the data extent. This ensure that
checksum for a given block is either valid or does not exist.

3) update data relocation code to properly handle the case
of checksum missing.

Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
2008-12-12 10:03:38 -05:00
Chris Mason
459931eca5 Btrfs: Delete csum items when freeing extents
This finishes off the new checksumming code by removing csum items
for extents that are no longer in use.

The trick is doing it without racing because a single csum item may
hold csums for more than one extent.  Extra checks are added to
btrfs_csum_file_blocks to make sure that we are using the correct
csum item after dropping locks.

A new btrfs_split_item is added to split a single csum item so it
can be split without dropping the leaf lock.  This is used to
remove csum bytes from the middle of an item.

Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-12-10 09:10:46 -05:00
Chris Mason
d20f7043fa Btrfs: move data checksumming into a dedicated tree
Btrfs stores checksums for each data block.  Until now, they have
been stored in the subvolume trees, indexed by the inode that is
referencing the data block.  This means that when we read the inode,
we've probably read in at least some checksums as well.

But, this has a few problems:

* The checksums are indexed by logical offset in the file.  When
compression is on, this means we have to do the expensive checksumming
on the uncompressed data.  It would be faster if we could checksum
the compressed data instead.

* If we implement encryption, we'll be checksumming the plain text and
storing that on disk.  This is significantly less secure.

* For either compression or encryption, we have to get the plain text
back before we can verify the checksum as correct.  This makes the raid
layer balancing and extent moving much more expensive.

* It makes the front end caching code more complex, as we have touch
the subvolume and inodes as we cache extents.

* There is potentitally one copy of the checksum in each subvolume
referencing an extent.

The solution used here is to store the extent checksums in a dedicated
tree.  This allows us to index the checksums by phyiscal extent
start and length.  It means:

* The checksum is against the data stored on disk, after any compression
or encryption is done.

* The checksum is stored in a central location, and can be verified without
following back references, or reading inodes.

This makes compression significantly faster by reducing the amount of
data that needs to be checksummed.  It will also allow much faster
raid management code in general.

The checksums are indexed by a key with a fixed objectid (a magic value
in ctree.h) and offset set to the starting byte of the extent.  This
allows us to copy the checksum items into the fsync log tree directly (or
any other tree), without having to invent a second format for them.

Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-12-08 16:58:54 -05:00
Josef Bacik
607d432da0 Btrfs: add support for multiple csum algorithms
This patch gives us the space we will need in order to have different csum
algorithims at some point in the future.  We save the csum algorithim type
in the superblock, and use those instead of define's.

Signed-off-by: Josef Bacik <jbacik@redhat.com>
2008-12-02 07:17:45 -05:00
Chris Mason
39be25cd89 Btrfs: Use invalidatepage when writepage finds a page outside of i_size
With all the recent fixes to the delalloc locking, it is now safe
again to use invalidatepage inside the writepage code for
pages outside of i_size.  This used to deadlock against some of the
code to write locked ranges of pages, but all of that has been fixed.

Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-11-10 11:50:50 -05:00
Chris Mason
c8b978188c Btrfs: Add zlib compression support
This is a large change for adding compression on reading and writing,
both for inline and regular extents.  It does some fairly large
surgery to the writeback paths.

Compression is off by default and enabled by mount -o compress.  Even
when the -o compress mount option is not used, it is possible to read
compressed extents off the disk.

If compression for a given set of pages fails to make them smaller, the
file is flagged to avoid future compression attempts later.

* While finding delalloc extents, the pages are locked before being sent down
to the delalloc handler.  This allows the delalloc handler to do complex things
such as cleaning the pages, marking them writeback and starting IO on their
behalf.

* Inline extents are inserted at delalloc time now.  This allows us to compress
the data before inserting the inline extent, and it allows us to insert
an inline extent that spans multiple pages.

* All of the in-memory extent representations (extent_map.c, ordered-data.c etc)
are changed to record both an in-memory size and an on disk size, as well
as a flag for compression.

From a disk format point of view, the extent pointers in the file are changed
to record the on disk size of a given extent and some encoding flags.
Space in the disk format is allocated for compression encoding, as well
as encryption and a generic 'other' field.  Neither the encryption or the
'other' field are currently used.

In order to limit the amount of data read for a single random read in the
file, the size of a compressed extent is limited to 128k.  This is a
software only limit, the disk format supports u64 sized compressed extents.

In order to limit the ram consumed while processing extents, the uncompressed
size of a compressed extent is limited to 256k.  This is a software only limit
and will be subject to tuning later.

Checksumming is still done on compressed extents, and it is done on the
uncompressed version of the data.  This way additional encodings can be
layered on without having to figure out which encoding to checksum.

Compression happens at delalloc time, which is basically singled threaded because
it is usually done by a single pdflush thread.  This makes it tricky to
spread the compression load across all the cpus on the box.  We'll have to
look at parallel pdflush walks of dirty inodes at a later time.

Decompression is hooked into readpages and it does spread across CPUs nicely.

Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-10-29 14:49:59 -04:00
Chris Mason
639cb58675 Btrfs: Fix variable init during csum creation
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-25 11:04:07 -04:00
Chris Mason
4d1b5fb4d7 Btrfs: Lookup readpage checksums on bio submission again
This optimization had been removed because I thought it was triggering
csum errors.  The real cause of the errors was elsewhere, and so
this optimization is back.

Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-25 11:04:06 -04:00
Chris Mason
53863232ef Btrfs: Lower contention on the csum mutex
This takes the csum mutex deeper in the call chain and releases it
more often.

Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-25 11:04:06 -04:00
Chris Mason
3de9d6b649 btrfs_lookup_bio_sums seems broken, go back to the readpage_io_hook for now
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-25 11:04:06 -04:00
Chris Mason
6dab815743 Btrfs: Hold csum mutex while reading in sums during readpages
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-25 11:04:06 -04:00
Chris Mason
61b4944018 Btrfs: Fix streaming read performance with checksumming on
Large streaming reads make for large bios, which means each entry on the
list async work queues represents a large amount of data.  IO
congestion throttling on the device was kicking in before the async
worker threads decided a single thread was busy and needed some help.

The end result was that a streaming read would result in a single CPU
running at 100% instead of balancing the work off to other CPUs.

This patch also changes the pre-IO checksum lookup done by reads to
work on a per-bio basis instead of a per-page.  This results in many
extra btree lookups on large streaming reads.  Doing the checksum lookup
right before bio submit allows us to reuse searches while processing
adjacent offsets.

Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-25 11:04:05 -04:00
Yan
bcc63abbf3 Btrfs: implement memory reclaim for leaf reference cache
The memory reclaiming issue happens when snapshot exists. In that
case, some cache entries may not be used during old snapshot dropping,
so they will remain in the cache until umount.

The patch adds a field to struct btrfs_leaf_ref to record create time. Besides,
the patch makes all dead roots of a given snapshot linked together in order of
create time. After a old snapshot was completely dropped, we check the dead
root list and remove all cache entries created before the oldest dead root in
the list.

Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-25 11:04:05 -04:00
Chris Mason
ed98b56a63 Btrfs: Take the csum mutex while reading checksums
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-25 11:04:05 -04:00
Chris Mason
e5a2217ef6 Fix btrfs_wait_ordered_extent_range to properly wait
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-25 11:04:05 -04:00
Chris Mason
7f3c74fb83 Btrfs: Keep extent mappings in ram until pending ordered extents are done
It was possible for stale mappings from disk to be used instead of the
new pending ordered extent.  This adds a flag to the extent map struct
to keep it pinned until the pending ordered extent is actually on disk.

Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-25 11:04:05 -04:00
Chris Mason
3edf7d33f4 Btrfs: Handle data checksumming on bios that span multiple ordered extents
Data checksumming is done right before the bio is sent down the IO stack,
which means a single bio might span more than one ordered extent.  In
this case, the checksumming data is split between two ordered extents.

Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-25 11:04:05 -04:00
Chris Mason
e6dcd2dc9c Btrfs: New data=ordered implementation
The old data=ordered code would force commit to wait until
all the data extents from the transaction were fully on disk.  This
introduced large latencies into the commit and stalled new writers
in the transaction for a long time.

The new code changes the way data allocations and extents work:

* When delayed allocation is filled, data extents are reserved, and
  the extent bit EXTENT_ORDERED is set on the entire range of the extent.
  A struct btrfs_ordered_extent is allocated an inserted into a per-inode
  rbtree to track the pending extents.

* As each page is written EXTENT_ORDERED is cleared on the bytes corresponding
  to that page.

* When all of the bytes corresponding to a single struct btrfs_ordered_extent
  are written, The previously reserved extent is inserted into the FS
  btree and into the extent allocation trees.  The checksums for the file
  data are also updated.

Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-25 11:04:04 -04:00
Sage Weil
f2eb0a241f Btrfs: Clone file data ioctl
Add a new ioctl to clone file data

Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-25 11:04:02 -04:00
Chris Mason
e015640f9c Btrfs: Write bio checksumming outside the FS mutex
This significantly improves streaming write performance by allowing
concurrency in the data checksumming.

Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-25 11:04:01 -04:00
Chris Mason
eb20978f31 Btrfs: Use KM_USERN instead of KM_IRQ during data summing
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-25 11:04:00 -04:00
Chris Mason
2e1a992e31 Btrfs: Make sure bio pages are adjacent during bulk csumming
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-25 11:04:00 -04:00
Chris Mason
6e92f5e651 Btrfs: While doing checksums on bios, cache the extent_buffer mapping
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-25 11:04:00 -04:00
Chris Mason
065631f6dc Btrfs: checksum file data at bio submission time instead of during writepage
When we checkum file data during writepage, the checksumming is done one
page at a time, making it difficult to do bulk metadata modifications
to insert checksums for large ranges of the file at once.

This patch changes btrfs to checksum on a per-bio basis instead.  The
bios are checksummed before they are handed off to the block layer, so
each bio is contiguous and only has pages from the same inode.

Checksumming on a bio basis allows us to insert and modify the file
checksum items in large groups.  It also allows the checksumming to
be done more easily by async worker threads.

Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-25 11:04:00 -04:00
Chris Mason
aadfeb6e39 Btrfs: Add some extra debugging around file data checksum failures
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-25 11:03:59 -04:00
Chris Mason
179e29e488 Btrfs: Fix a number of inline extent problems that Yan Zheng reported.
The fixes do a number of things:

1) Most btrfs_drop_extent callers will try to leave the inline extents in
place.  It can truncate bytes off the beginning of the inline extent if
required.

2) writepage can now update the inline extent, allowing mmap writes to
go directly into the inline extent.

3) btrfs_truncate_in_transaction truncates inline extents

4) extent_map.c fixed to not merge inline extent mappings and hole
mappings together

Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-25 11:03:57 -04:00
Yan
b56baf5bed Minor fix for btrfs_csum_file_block.
Execution should goto label 'insert' when 'btrfs_next_leaf' return a
non-zero value, otherwise the parameter 'slot' for
'btrfs_item_key_to_cpu' may be out of bounds. The original codes jump
to  label 'insert' only when 'btrfs_next_leaf' return a negative
value.

Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-25 11:03:57 -04:00
Chris Mason
f578d4bd7e Btrfs: Optimize csum insertion to create larger items when possible
This reduces the number of calls to btrfs_extend_item and greatly lowers
the cpu usage while writing large files.

Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-25 11:03:57 -04:00
Chris Mason
ff79f8190b Btrfs: Add back file data checksumming
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-25 11:03:57 -04:00
Chris Mason
db94535db7 Btrfs: Allow tree blocks larger than the page size
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-25 11:03:56 -04:00
Chris Mason
5f39d397df Btrfs: Create extent_buffer interface for large blocksizes
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-25 11:03:56 -04:00
Zach Brown
ec6b910fb3 Btrfs: trivial include fixups
Almost none of the files including module.h need to do so,
remove them.

Include sched.h in extent-tree.c to silence a warning about cond_resched()
being undeclared.

Signed-off-by: Zach Brown <zach.brown@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2007-07-11 10:00:37 -04:00
Chris Mason
54aa1f4dfd Btrfs: Audit callers and return codes to make sure -ENOSPC gets up the stack
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2007-06-22 14:16:25 -04:00
Chris Mason
8c2383c3dd Subject: Rework btrfs_file_write to only allocate while page locks are held
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2007-06-18 09:57:58 -04:00
Chris Mason
9ebefb180b Btrfs: patch queue: page_mkwrite
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2007-06-15 13:50:00 -04:00
Aneesh
f1ace244c8 btrfs: Code cleanup
Attaching below is some of the code cleanups that i came across while
reading the code.

a) alloc_path already calls init_path.
b) Mention that btrfs_inode is the in memory copy.Ext4 have ext4_inode_info as
the in memory copy ext4_inode as the disk copy

Signed-off-by: Chris Mason <chris.mason@oracle.com>
2007-06-13 16:18:26 -04:00
Chris Mason
6cbd557078 Btrfs: add GPLv2
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2007-06-12 09:07:21 -04:00
Chris Mason
5af3981c18 Btrfs: printk fixes
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2007-06-12 07:50:13 -04:00
Chris Mason
84f54cfa78 Btrfs: 64 bit div fixes
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2007-06-12 07:43:08 -04:00
Chris Mason
1de037a43e Btrfs: fixup various fsx failures
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2007-05-29 15:17:08 -04:00
Chris Mason
3a68637562 Btrfs: sparse files!
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2007-05-24 13:35:57 -04:00
Chris Mason
509659cde5 Btrfs: switch to crc32c instead of sha256
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2007-05-10 12:36:17 -04:00
Chris Mason
236454dfff Btrfs: many file_write fixes, inline data
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2007-04-19 13:37:44 -04:00
Chris Mason
a429e51371 Btrfs: working file_write, reorganized key flags
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2007-04-18 16:15:28 -04:00
Chris Mason
70b2befd0c Btrfs: rework csums and extent item ordering
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2007-04-17 15:39:32 -04:00
Chris Mason
b18c668581 Btrfs: progress on file_write
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2007-04-17 13:26:50 -04:00
Chris Mason
6567e837df Btrfs: early work to file_write in big extents
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2007-04-16 09:22:45 -04:00
Chris Mason
d0dbc6245c Btrfs: drop owner and parentid
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2007-04-10 12:36:36 -04:00
Chris Mason
2da566edd8 Btrfs: csum_verify_file_block locking fix
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2007-04-02 15:43:21 -04:00