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| author | Chris Mason <chris.mason@oracle.com> | 2007-10-15 16:14:27 -0400 |
|---|---|---|
| committer | Chris Mason <chris.mason@oracle.com> | 2008-09-25 11:03:56 -0400 |
| commit | 479965d66e320f1a095bb76027171daa675a9c72 (patch) | |
| tree | e8b57bf49e2c0eb37e5dbd389f716e4dc21d54dc /fs/btrfs/extent_map.c | |
| parent | 5f39d397dfbe140a14edecd4e73c34ce23c4f9ee (diff) | |
| download | linux-stable-479965d66e320f1a095bb76027171daa675a9c72.tar.gz linux-stable-479965d66e320f1a095bb76027171daa675a9c72.tar.bz2 linux-stable-479965d66e320f1a095bb76027171daa675a9c72.zip | |
Btrfs: Optimizations for the extent_buffer code
Signed-off-by: Chris Mason <chris.mason@oracle.com>
Diffstat (limited to 'fs/btrfs/extent_map.c')
| -rw-r--r-- | fs/btrfs/extent_map.c | 11 |
1 files changed, 8 insertions, 3 deletions
diff --git a/fs/btrfs/extent_map.c b/fs/btrfs/extent_map.c index 55fefdfab84c..8bef309e1b37 100644 --- a/fs/btrfs/extent_map.c +++ b/fs/btrfs/extent_map.c @@ -2140,14 +2140,20 @@ void read_extent_buffer(struct extent_buffer *eb, void *dstv, EXPORT_SYMBOL(read_extent_buffer); int map_extent_buffer(struct extent_buffer *eb, unsigned long start, + unsigned long min_len, char **token, char **map, unsigned long *map_start, unsigned long *map_len, int km) { - size_t offset; + size_t offset = start & (PAGE_CACHE_SIZE - 1); char *kaddr; size_t start_offset = eb->start & ((u64)PAGE_CACHE_SIZE - 1); unsigned long i = (start_offset + start) >> PAGE_CACHE_SHIFT; + unsigned long end_i = (start_offset + start + min_len) >> + PAGE_CACHE_SHIFT; + + if (i != end_i) + return -EINVAL; WARN_ON(start > eb->len); @@ -2155,8 +2161,7 @@ int map_extent_buffer(struct extent_buffer *eb, unsigned long start, offset = start_offset; *map_start = 0; } else { - offset = 0; - *map_start = (i << PAGE_CACHE_SHIFT) - offset; + *map_start = (i << PAGE_CACHE_SHIFT) - start_offset; } // kaddr = kmap_atomic(eb->pages[i], km); |