linux.git/fs/btrfs/compression.c, branch v4.11

btrfs: derive maximum output size in the compression implementation

2017-02-28T13:26:36+00:00

The value of max_out can be calculated from the parameters passed to the
compressors, which is number of pages and the page size, and we don't
have to needlessly pass it around.

Signed-off-by: David Sterba

btrfs: merge nr_pages input and output parameter in compress_pages

2017-02-28T13:26:35+00:00

The parameter saying how many pages can be allocated at maximum can be
merged with the output page counter, to save some stack space.  The
compression implementation will sink the parameter to a local variable
so everything works as before.

The nr_pages variables can also be simply merged in compress_file_range
into one.

Signed-off-by: David Sterba

btrfs: merge length input and output parameter in compress_pages

2017-02-28T13:26:35+00:00

The length parameter is basically duplicated for input and output in the
top level caller of the compress_pages chain. We can simply use one
variable for that and reduce stack consumption. The compression
implementation will sink the parameter to a local variable so everything
works as before.

Signed-off-by: David Sterba

btrfs: constify buffers used by compression helpers

2017-02-28T13:26:07+00:00

Signed-off-by: David Sterba

btrfs: make check_compressed_csum take btrfs_inode

2017-02-28T10:30:09+00:00

Signed-off-by: Nikolay Borisov 
Signed-off-by: David Sterba

btrfs: make btrfs_print_data_csum_error take btrfs_inode

2017-02-28T10:30:09+00:00

Signed-off-by: Nikolay Borisov 
Signed-off-by: David Sterba

btrfs: Better csum error message for data csum mismatch

2017-02-17T11:03:48+00:00

The original csum error message only outputs inode number, offset, check
sum and expected check sum.

However no root objectid is outputted, which sometimes makes debugging
quite painful under multi-subvolume case (including relocation).

Also the checksum output is decimal, which seldom makes sense for
users/developers and is hard to read in most time.

This patch will add root objectid, which will be %lld for rootid larger
than LAST_FREE_OBJECTID, and hex csum output for better readability.

Signed-off-by: Qu Wenruo 
Reviewed-by: David Sterba 
Signed-off-by: David Sterba

btrfs: Make btrfs_ino take a struct btrfs_inode

2017-02-14T14:50:51+00:00

Currently btrfs_ino takes a struct inode and this causes a lot of
internal btrfs functions which consume this ino to take a VFS inode,
rather than btrfs' own struct btrfs_inode. In order to fix this "leak"
of VFS structs into the internals of btrfs first it's necessary to
eliminate all uses of struct inode for the purpose of inode. This patch
does that by using BTRFS_I to convert an inode to btrfs_inode. With
this problem eliminated subsequent patches will start eliminating the
passing of struct inode altogether, eventually resulting in a lot cleaner
code.

Signed-off-by: Nikolay Borisov 
[ fix btrfs_get_extent tracepoint prototype ]
Signed-off-by: David Sterba

Btrfs: fix btrfs_decompress_buf2page()

2017-02-11T03:11:03+00:00

If btrfs_decompress_buf2page() is handed a bio with its page in the
middle of the working buffer, then we adjust the offset into the working
buffer. After we copy into the bio, we advance the iterator by the
number of bytes we copied. Then, we have some logic to handle the case
of discontiguous pages and adjust the offset into the working buffer
again. However, if we didn't advance the bio to a new page, we may enter
this case in error, essentially repeating the adjustment that we already
made when we entered the function. The end result is bogus data in the
bio.

Previously, we only checked for this case when we advanced to a new
page, but the conversion to bio iterators changed that. This restores
the old, correct behavior.

A case I saw when testing with zlib was:

    buf_start = 42769
    total_out = 46865
    working_bytes = total_out - buf_start = 4096
    start_byte = 45056

The condition (total_out > start_byte && buf_start < start_byte) is
true, so we adjust the offset:

    buf_offset = start_byte - buf_start = 2287
    working_bytes -= buf_offset = 1809
    current_buf_start = buf_start = 42769

Then, we copy

    bytes = min(bvec.bv_len, PAGE_SIZE - buf_offset, working_bytes) = 1809
    buf_offset += bytes = 4096
    working_bytes -= bytes = 0
    current_buf_start += bytes = 44578

After bio_advance(), we are still in the same page, so start_byte is the
same. Then, we check (total_out > start_byte && current_buf_start < start_byte),
which is true! So, we adjust the values again:

    buf_offset = start_byte - buf_start = 2287
    working_bytes = total_out - start_byte = 1809
    current_buf_start = buf_start + buf_offset = 45056

But note that working_bytes was already zero before this, so we should
have stopped copying.

Fixes: 974b1adc3b10 ("btrfs: use bio iterators for the decompression handlers")
Reported-by: Pat Erley 
Reviewed-by: Chris Mason 
Signed-off-by: Omar Sandoval 
Signed-off-by: Chris Mason 
Reviewed-by: Liu Bo 
Tested-by: Liu Bo

btrfs: take an fs_info directly when the root is not used otherwise

2016-12-06T15:06:59+00:00

There are loads of functions in btrfs that accept a root parameter
but only use it to obtain an fs_info pointer.  Let's convert those to
just accept an fs_info pointer directly.

Signed-off-by: Jeff Mahoney 
Signed-off-by: David Sterba