diff options
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 55fefdfab84..8bef309e1b3 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); |