From mboxrd@z Thu Jan 1 00:00:00 1970 From: jim owens Subject: [PATCH V3 10/18] Btrfs: add direct I/O helper to process inline compressed extents. Date: Sun, 21 Mar 2010 23:27:18 -0400 Message-ID: <4BA6E396.1040104@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 To: linux-btrfs Return-path: List-ID: Use access_extent_buffer_page() to point at btree location of inline compressed data so it can be inflated without a memcopy. Signed-off-by: jim owens --- fs/btrfs/extent_io.c | 16 ++++++++++++++++ fs/btrfs/extent_io.h | 8 ++++++-- 2 files changed, 22 insertions(+), 2 deletions(-) diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c index c99121a..5a5370d 100644 --- a/fs/btrfs/extent_io.c +++ b/fs/btrfs/extent_io.c @@ -3072,6 +3072,22 @@ static inline struct page *extent_buffer_page(struct extent_buffer *eb, return p; } +void access_extent_buffer_page(struct bio_vec *vec, struct extent_buffer *eb, + unsigned long start, unsigned long len) +{ + size_t start_offset = eb->start & ((u64)PAGE_CACHE_SIZE - 1); + unsigned long i = (start_offset + start) >> PAGE_CACHE_SHIFT; + size_t offset = (start_offset + start) & + ((unsigned long)PAGE_CACHE_SIZE - 1); + + WARN_ON(start > eb->len); + WARN_ON(start + len > eb->start + eb->len); + + vec->bv_page = extent_buffer_page(eb, i); + vec->bv_offset = offset; + vec->bv_len = min(len, (PAGE_CACHE_SIZE - offset)); +} + static inline unsigned long num_extent_pages(u64 start, u64 len) { return ((start + len + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT) - diff --git a/fs/btrfs/extent_io.h b/fs/btrfs/extent_io.h index bbab481..9356be1 100644 --- a/fs/btrfs/extent_io.h +++ b/fs/btrfs/extent_io.h @@ -2,6 +2,7 @@ #define __EXTENTIO__ #include +#include /* bits for the extent state */ #define EXTENT_DIRTY 1 @@ -181,8 +182,8 @@ int test_range_bit(struct extent_io_tree *tree, u64 start, u64 end, int clear_extent_bits(struct extent_io_tree *tree, u64 start, u64 end, int bits, gfp_t mask); int clear_extent_bit(struct extent_io_tree *tree, u64 start, u64 end, - int bits, int wake, int delete, struct extent_state **cached, - gfp_t mask); + int bits, int wake, int delete, + struct extent_state **cached, gfp_t mask); int set_extent_bits(struct extent_io_tree *tree, u64 start, u64 end, int bits, gfp_t mask); int set_extent_uptodate(struct extent_io_tree *tree, u64 start, u64 end, @@ -304,4 +305,7 @@ int extent_clear_unlock_delalloc(struct inode *inode, struct extent_io_tree *tree, u64 start, u64 end, struct page *locked_page, unsigned long op); +extern void access_extent_buffer_page(struct bio_vec *vec, + struct extent_buffer *eb, + unsigned long start, unsigned long len); #endif -- 1.6.3.3