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btrfs: use bio iterators for the decompression handlers

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Pass the full bio to the decompression routines and use bio iterators
to iterate over the data in the bio.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: David Sterba <dsterba@suse.com>
This commit is contained in:
Christoph Hellwig
2016-11-25 09:07:46 +01:00
committed by David Sterba
parent 0c476a5d7f
commit 974b1adc3b
4 changed files with 56 additions and 113 deletions
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125
fs/btrfs/compression.c
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@@ -81,9 +81,9 @@ struct compressed_bio {
u32 sums;
};
static int btrfs_decompress_biovec(int type, struct page **pages_in,
u64 disk_start, struct bio_vec *bvec,
int vcnt, size_t srclen);
static int btrfs_decompress_bio(int type, struct page **pages_in,
u64 disk_start, struct bio *orig_bio,
size_t srclen);
static inline int compressed_bio_size(struct btrfs_root *root,
unsigned long disk_size)
@@ -175,11 +175,10 @@ static void end_compressed_bio_read(struct bio *bio)
/* ok, we're the last bio for this extent, lets start
* the decompression.
*/
ret = btrfs_decompress_biovec(cb->compress_type,
ret = btrfs_decompress_bio(cb->compress_type,
cb->compressed_pages,
cb->start,
cb->orig_bio->bi_io_vec,
cb->orig_bio->bi_vcnt,
cb->orig_bio,
cb->compressed_len);
csum_failed:
if (ret)
@@ -959,9 +958,7 @@ int btrfs_compress_pages(int type, struct address_space *mapping,
*
* disk_start is the starting logical offset of this array in the file
*
* bvec is a bio_vec of pages from the file that we want to decompress into
*
* vcnt is the count of pages in the biovec
* orig_bio contains the pages from the file that we want to decompress into
*
* srclen is the number of bytes in pages_in
*
@@ -970,18 +967,18 @@ int btrfs_compress_pages(int type, struct address_space *mapping,
* be contiguous. They all correspond to the range of bytes covered by
* the compressed extent.
*/
static int btrfs_decompress_biovec(int type, struct page **pages_in,
u64 disk_start, struct bio_vec *bvec,
int vcnt, size_t srclen)
static int btrfs_decompress_bio(int type, struct page **pages_in,
u64 disk_start, struct bio *orig_bio,
size_t srclen)
{
struct list_head *workspace;
int ret;
workspace = find_workspace(type);
ret = btrfs_compress_op[type-1]->decompress_biovec(workspace, pages_in,
disk_start,
bvec, vcnt, srclen);
ret = btrfs_compress_op[type-1]->decompress_bio(workspace, pages_in,
disk_start, orig_bio,
srclen);
free_workspace(type, workspace);
return ret;
}
@@ -1021,9 +1018,7 @@ void btrfs_exit_compress(void)
*/
int btrfs_decompress_buf2page(char *buf, unsigned long buf_start,
unsigned long total_out, u64 disk_start,
struct bio_vec *bvec, int vcnt,
unsigned long *pg_index,
unsigned long *pg_offset)
struct bio *bio)
{
unsigned long buf_offset;
unsigned long current_buf_start;
@@ -1031,13 +1026,13 @@ int btrfs_decompress_buf2page(char *buf, unsigned long buf_start,
unsigned long working_bytes = total_out - buf_start;
unsigned long bytes;
char *kaddr;
struct page *page_out = bvec[*pg_index].bv_page;
struct bio_vec bvec = bio_iter_iovec(bio, bio->bi_iter);
/*
* start byte is the first byte of the page we're currently
* copying into relative to the start of the compressed data.
*/
start_byte = page_offset(page_out) - disk_start;
start_byte = page_offset(bvec.bv_page) - disk_start;
/* we haven't yet hit data corresponding to this page */
if (total_out <= start_byte)
@@ -1057,80 +1052,46 @@ int btrfs_decompress_buf2page(char *buf, unsigned long buf_start,
/* copy bytes from the working buffer into the pages */
while (working_bytes > 0) {
bytes = min(PAGE_SIZE - *pg_offset,
PAGE_SIZE - buf_offset);
bytes = min_t(unsigned long, bvec.bv_len,
PAGE_SIZE - buf_offset);
bytes = min(bytes, working_bytes);
kaddr = kmap_atomic(page_out);
memcpy(kaddr + *pg_offset, buf + buf_offset, bytes);
kunmap_atomic(kaddr);
flush_dcache_page(page_out);
*pg_offset += bytes;
kaddr = kmap_atomic(bvec.bv_page);
memcpy(kaddr + bvec.bv_offset, buf + buf_offset, bytes);
kunmap_atomic(kaddr);
flush_dcache_page(bvec.bv_page);
buf_offset += bytes;
working_bytes -= bytes;
current_buf_start += bytes;
/* check if we need to pick another page */
if (*pg_offset == PAGE_SIZE) {
(*pg_index)++;
if (*pg_index >= vcnt)
return 0;
bio_advance(bio, bytes);
if (!bio->bi_iter.bi_size)
return 0;
bvec = bio_iter_iovec(bio, bio->bi_iter);
page_out = bvec[*pg_index].bv_page;
*pg_offset = 0;
start_byte = page_offset(page_out) - disk_start;
start_byte = page_offset(bvec.bv_page) - disk_start;
/*
* make sure our new page is covered by this
* working buffer
*/
if (total_out <= start_byte)
return 1;
/*
* make sure our new page is covered by this
* working buffer
*/
if (total_out <= start_byte)
return 1;
/*
* the next page in the biovec might not be adjacent
* to the last page, but it might still be found
* inside this working buffer. bump our offset pointer
*/
if (total_out > start_byte &&
current_buf_start < start_byte) {
buf_offset = start_byte - buf_start;
working_bytes = total_out - start_byte;
current_buf_start = buf_start + buf_offset;
}
/*
* the next page in the biovec might not be adjacent
* to the last page, but it might still be found
* inside this working buffer. bump our offset pointer
*/
if (total_out > start_byte &&
current_buf_start < start_byte) {
buf_offset = start_byte - buf_start;
working_bytes = total_out - start_byte;
current_buf_start = buf_start + buf_offset;
}
}
return 1;
}
/*
* When uncompressing data, we need to make sure and zero any parts of
* the biovec that were not filled in by the decompression code. pg_index
* and pg_offset indicate the last page and the last offset of that page
* that have been filled in. This will zero everything remaining in the
* biovec.
*/
void btrfs_clear_biovec_end(struct bio_vec *bvec, int vcnt,
unsigned long pg_index,
unsigned long pg_offset)
{
while (pg_index < vcnt) {
struct page *page = bvec[pg_index].bv_page;
unsigned long off = bvec[pg_index].bv_offset;
unsigned long len = bvec[pg_index].bv_len;
if (pg_offset < off)
pg_offset = off;
if (pg_offset < off + len) {
unsigned long bytes = off + len - pg_offset;
char *kaddr;
kaddr = kmap_atomic(page);
memset(kaddr + pg_offset, 0, bytes);
kunmap_atomic(kaddr);
}
pg_index++;
pg_offset = 0;
}
}