linux.git/fs/btrfs/zlib.c, branch v4.2

btrfs: constify structs with op functions or static definitions

2015-02-16T17:48:44+00:00

There are some op tables that can be easily made const, similarly the
sysfs feature and raid tables. This is motivated by PaX CONSTIFY plugin.

Signed-off-by: David Sterba

btrfs: zero out left over bytes after processing compression streams

2014-11-30T17:33:51+00:00

Don Bailey noticed that our page zeroing for compression at end-io time
isn't complete.  This reworks a patch from Linus to push the zeroing
into the zlib and lzo specific functions instead of trying to handle the
corners inside btrfs_decompress_buf2page

Signed-off-by: Chris Mason 
Reviewed-by: Josef Bacik 
Reported-by: Don A. Bailey 
cc: stable@vger.kernel.org
Signed-off-by: Linus Torvalds

btrfs compression: merge inflate and deflate z_streams

2014-09-17T20:37:33+00:00

`struct workspace' used for zlib compression contains two zlib
z_stream-s: `def_strm' used in zlib_compress_pages(), and `inf_strm'
used in zlib_decompress/zlib_decompress_biovec(). None of these
functions use `inf_strm' and `def_strm' simultaniously, meaning that
for every compress/decompress operation we need only one z_stream
(out of two available).

`inf_strm' and `def_strm' are different in size of ->workspace. For
inflate stream we vmalloc() zlib_inflate_workspacesize() bytes, for
deflate stream - zlib_deflate_workspacesize() bytes. On my system zlib
returns the following workspace sizes, correspondingly: 42312 and 268104
(+ guard pages).

Keep only one `z_stream' in `struct workspace' and use it for both
compression and decompression. Hence, instead of vmalloc() of two
z_stream->worskpace-s, allocate only one of size:
	max(zlib_deflate_workspacesize(), zlib_inflate_workspacesize())

Reviewed-by: David Sterba 
Signed-off-by: Sergey Senozhatsky 
Signed-off-by: Chris Mason

btrfs: use DIV_ROUND_UP instead of open-coded variants

2014-09-17T20:37:17+00:00

The form

  (value + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT

is equivalent to

  (value + PAGE_CACHE_SIZE - 1) / PAGE_CACHE_SIZE

The rest is a simple subsitution, no difference in the generated
assembly code.

Signed-off-by: David Sterba 
Signed-off-by: Chris Mason

btrfs: use E2BIG instead of EIO if compression does not help

2014-07-03T14:04:13+00:00

Return codes got updated in 60e1975acb48fc3d74a3422b21dde74c977ac3d5
(btrfs: return errno instead of -1 from compression)
lzo wrapper returns E2BIG in this case, do the same for zlib.

Signed-off-by: David Sterba

btrfs: return errno instead of -1 from compression

2014-06-10T00:20:21+00:00

The compression layer seems to have been built to return -1 and have
callers make up errors that make sense.  This isn't great because there
are different errors that originate down in the compression layer.

Let's return real negative errnos from the compression layer so that
callers can pass on the error without having to guess what happened.
ENOMEM for allocation failure, E2BIG when compression exceeds the
uncompressed input, and EIO for everything else.

This helps a future path return errors from btrfs_decompress().

Signed-off-by: Zach Brown 
Signed-off-by: Chris Mason

Btrfs: convert printk to btrfs_ and fix BTRFS prefix

2014-01-28T21:20:05+00:00

Convert all applicable cases of printk and pr_* to the btrfs_* macros.

Fix all uses of the BTRFS prefix.

Signed-off-by: Frank Holton 
Signed-off-by: Josef Bacik 
Signed-off-by: Chris Mason

btrfs: fix message printing

2012-10-09T13:19:57+00:00

Fix various messages to include newline and module prefix.

Signed-off-by: Daniel J Blueman

btrfs: remove the second argument of k[un]map_atomic()

2012-03-20T13:48:21+00:00

Signed-off-by: Cong Wang

zlib: slim down zlib_deflate() workspace when possible

2011-03-23T00:44:17+00:00

Instead of always creating a huge (268K) deflate_workspace with the
maximum compression parameters (windowBits=15, memLevel=8), allow the
caller to obtain a smaller workspace by specifying smaller parameter
values.

For example, when capturing oops and panic reports to a medium with
limited capacity, such as NVRAM, compression may be the only way to
capture the whole report.  In this case, a small workspace (24K works
fine) is a win, whether you allocate the workspace when you need it (i.e.,
during an oops or panic) or at boot time.

I've verified that this patch works with all accepted values of windowBits
(positive and negative), memLevel, and compression level.

Signed-off-by: Jim Keniston 
Cc: Herbert Xu 
Cc: David Miller 
Cc: Chris Mason 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds