diff options
Diffstat (limited to 'fs/btrfs/extent_map.c')
-rw-r--r-- | fs/btrfs/extent_map.c | 91 |
1 files changed, 66 insertions, 25 deletions
diff --git a/fs/btrfs/extent_map.c b/fs/btrfs/extent_map.c index e081558d52f..f658703c42e 100644 --- a/fs/btrfs/extent_map.c +++ b/fs/btrfs/extent_map.c @@ -1963,18 +1963,27 @@ static inline struct page *extent_buffer_page(struct extent_buffer *eb, int i) struct page *p; if (i == 0) return eb->first_page; + i += eb->start >> PAGE_CACHE_SHIFT; + if (eb->last_page && eb->last_page->index == i) + return eb->last_page; + p = find_get_page(eb->first_page->mapping, i); page_cache_release(p); + eb->last_page = p; return p; } +static inline unsigned long num_extent_pages(u64 start, u64 len) +{ + return ((start + len + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT) - + (start >> PAGE_CACHE_SHIFT); +} struct extent_buffer *alloc_extent_buffer(struct extent_map_tree *tree, u64 start, unsigned long len, gfp_t mask) { - unsigned long num_pages = ((start + len - 1) >> PAGE_CACHE_SHIFT) - - (start >> PAGE_CACHE_SHIFT) + 1; + unsigned long num_pages = num_extent_pages(start, len); unsigned long i; unsigned long index = start >> PAGE_CACHE_SHIFT; struct extent_buffer *eb; @@ -1986,7 +1995,7 @@ struct extent_buffer *alloc_extent_buffer(struct extent_map_tree *tree, if (!eb || IS_ERR(eb)) return NULL; - eb->alloc_addr = __builtin_return_address(0); + eb->alloc_addr = (unsigned long)__builtin_return_address(0); eb->start = start; eb->len = len; atomic_set(&eb->refs, 1); @@ -1994,6 +2003,7 @@ struct extent_buffer *alloc_extent_buffer(struct extent_map_tree *tree, for (i = 0; i < num_pages; i++, index++) { p = find_or_create_page(mapping, index, mask | __GFP_HIGHMEM); if (!p) { + WARN_ON(1); /* make sure the free only frees the pages we've * grabbed a reference on */ @@ -2021,8 +2031,7 @@ struct extent_buffer *find_extent_buffer(struct extent_map_tree *tree, u64 start, unsigned long len, gfp_t mask) { - unsigned long num_pages = ((start + len - 1) >> PAGE_CACHE_SHIFT) - - (start >> PAGE_CACHE_SHIFT) + 1; + unsigned long num_pages = num_extent_pages(start, len); unsigned long i; unsigned long index = start >> PAGE_CACHE_SHIFT; struct extent_buffer *eb; @@ -2033,7 +2042,7 @@ struct extent_buffer *find_extent_buffer(struct extent_map_tree *tree, if (!eb || IS_ERR(eb)) return NULL; - eb->alloc_addr = __builtin_return_address(0); + eb->alloc_addr = (unsigned long)__builtin_return_address(0); eb->start = start; eb->len = len; atomic_set(&eb->refs, 1); @@ -2070,8 +2079,7 @@ void free_extent_buffer(struct extent_buffer *eb) if (!atomic_dec_and_test(&eb->refs)) return; - num_pages = ((eb->start + eb->len - 1) >> PAGE_CACHE_SHIFT) - - (eb->start >> PAGE_CACHE_SHIFT) + 1; + num_pages = num_extent_pages(eb->start, eb->len); if (eb->first_page) page_cache_release(eb->first_page); @@ -2094,8 +2102,7 @@ int clear_extent_buffer_dirty(struct extent_map_tree *tree, u64 end = start + eb->len - 1; set = clear_extent_dirty(tree, start, end, GFP_NOFS); - num_pages = ((eb->start + eb->len - 1) >> PAGE_CACHE_SHIFT) - - (eb->start >> PAGE_CACHE_SHIFT) + 1; + num_pages = num_extent_pages(eb->start, eb->len); for (i = 0; i < num_pages; i++) { page = extent_buffer_page(eb, i); @@ -2145,8 +2152,7 @@ int set_extent_buffer_uptodate(struct extent_map_tree *tree, struct page *page; unsigned long num_pages; - num_pages = ((eb->start + eb->len - 1) >> PAGE_CACHE_SHIFT) - - (eb->start >> PAGE_CACHE_SHIFT) + 1; + num_pages = num_extent_pages(eb->start, eb->len); set_extent_uptodate(tree, eb->start, eb->start + eb->len - 1, GFP_NOFS); @@ -2191,8 +2197,7 @@ int read_extent_buffer_pages(struct extent_map_tree *tree, return 0; } - num_pages = ((eb->start + eb->len - 1) >> PAGE_CACHE_SHIFT) - - (eb->start >> PAGE_CACHE_SHIFT) + 1; + num_pages = num_extent_pages(eb->start, eb->len); for (i = 0; i < num_pages; i++) { page = extent_buffer_page(eb, i); if (PageUptodate(page)) { @@ -2267,14 +2272,14 @@ 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) +static 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 = start & (PAGE_CACHE_SIZE - 1); char *kaddr; + struct page *p; 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) >> @@ -2283,21 +2288,59 @@ int map_extent_buffer(struct extent_buffer *eb, unsigned long start, if (i != end_i) return -EINVAL; - WARN_ON(start > eb->len); + if (start >= eb->len) { + printk("bad start in map eb start %Lu len %lu caller start %lu min %lu\n", eb->start, eb->len, start, min_len); + WARN_ON(1); + } if (i == 0) { offset = start_offset; *map_start = 0; } else { + offset = 0; *map_start = (i << PAGE_CACHE_SHIFT) - start_offset; } - kaddr = kmap_atomic(extent_buffer_page(eb, i), km); + p = extent_buffer_page(eb, i); + WARN_ON(!PageUptodate(p)); + kaddr = kmap_atomic(p, km); *token = kaddr; *map = kaddr + offset; *map_len = PAGE_CACHE_SIZE - offset; return 0; } + +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) +{ + int err; + int save = 0; + if (eb->map_token) { + if (start >= eb->map_start && + start + min_len <= eb->map_start + eb->map_len) { + *token = eb->map_token; + *map = eb->kaddr; + *map_start = eb->map_start; + *map_len = eb->map_len; + return 0; + } + unmap_extent_buffer(eb, eb->map_token, km); + eb->map_token = NULL; + save = 1; + } + err = __map_extent_buffer(eb, start, min_len, token, map, + map_start, map_len, km); + if (!err && save) { + eb->map_token = *token; + eb->kaddr = *map; + eb->map_start = *map_start; + eb->map_len = *map_len; + } + return err; +} EXPORT_SYMBOL(map_extent_buffer); void unmap_extent_buffer(struct extent_buffer *eb, char *token, int km) @@ -2574,7 +2617,6 @@ void memmove_extent_buffer(struct extent_buffer *dst, unsigned long dst_offset, ((unsigned long)PAGE_CACHE_SIZE - 1); src_off_in_page = src_end & ((unsigned long)PAGE_CACHE_SIZE - 1); - if (src_i == 0) src_off_in_page += start_offset; if (dst_i == 0) @@ -2582,14 +2624,13 @@ void memmove_extent_buffer(struct extent_buffer *dst, unsigned long dst_offset, cur = min(len, src_off_in_page + 1); cur = min(cur, dst_off_in_page + 1); - move_pages(extent_buffer_page(dst, dst_i), extent_buffer_page(dst, src_i), dst_off_in_page - cur + 1, src_off_in_page - cur + 1, cur); - dst_end -= cur - 1; - src_end -= cur - 1; + dst_end -= cur; + src_end -= cur; len -= cur; } } |