[PATCH v2 5/5] btrfs: fiemap: return extent physical size

[Sweet Tea Dorminy <sweettea-kernel@dorminy.me>]

Now that fiemap allows returning extent physical size, make btrfs return
the appropriate extent's actual disk size.

Signed-off-by: Sweet Tea Dorminy <sweettea-kernel@dorminy.me>
---
 fs/btrfs/extent_io.c | 70 ++++++++++++++++++++++++++++----------------
 1 file changed, 45 insertions(+), 25 deletions(-)

diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index 30fcbb9393fe..9921dc1567d6 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -2456,7 +2456,8 @@ int try_release_extent_mapping(struct page *page, gfp_t mask)
 struct btrfs_fiemap_entry {
 	u64 offset;
 	u64 phys;
-	u64 len;
+	u64 log_len;
+	u64 phys_len;
 	u32 flags;
 };
 
@@ -2514,7 +2515,8 @@ struct fiemap_cache {
 	/* Fields for the cached extent (unsubmitted, not ready, extent). */
 	u64 offset;
 	u64 phys;
-	u64 len;
+	u64 log_len;
+	u64 phys_len;
 	u32 flags;
 	bool cached;
 };
@@ -2527,8 +2529,8 @@ static int flush_fiemap_cache(struct fiemap_extent_info *fieinfo,
 		int ret;
 
 		ret = fiemap_fill_next_extent(fieinfo, entry->offset,
-					      entry->phys, entry->len, 0,
-					      entry->flags);
+					      entry->phys, entry->log_len,
+					      entry->phys_len, entry->flags);
 		/*
 		 * Ignore 1 (reached max entries) because we keep track of that
 		 * ourselves in emit_fiemap_extent().
@@ -2553,7 +2555,8 @@ static int flush_fiemap_cache(struct fiemap_extent_info *fieinfo,
  */
 static int emit_fiemap_extent(struct fiemap_extent_info *fieinfo,
 				struct fiemap_cache *cache,
-				u64 offset, u64 phys, u64 len, u32 flags)
+				u64 offset, u64 phys, u64 log_len,
+				u64 phys_len, u32 flags)
 {
 	struct btrfs_fiemap_entry *entry;
 	u64 cache_end;
@@ -2561,6 +2564,9 @@ static int emit_fiemap_extent(struct fiemap_extent_info *fieinfo,
 	/* Set at the end of extent_fiemap(). */
 	ASSERT((flags & FIEMAP_EXTENT_LAST) == 0);
 
+	/* We always set the correct physical length. */
+	flags |= FIEMAP_EXTENT_HAS_PHYS_LEN;
+
 	if (!cache->cached)
 		goto assign;
 
@@ -2596,7 +2602,7 @@ static int emit_fiemap_extent(struct fiemap_extent_info *fieinfo,
 	 * or equals to what we have in cache->offset. We deal with this as
 	 * described below.
 	 */
-	cache_end = cache->offset + cache->len;
+	cache_end = cache->offset + cache->log_len;
 	if (cache_end > offset) {
 		if (offset == cache->offset) {
 			/*
@@ -2620,10 +2626,10 @@ static int emit_fiemap_extent(struct fiemap_extent_info *fieinfo,
 			 * where a previously found file extent item was split
 			 * due to an ordered extent completing.
 			 */
-			cache->len = offset - cache->offset;
+			cache->log_len = offset - cache->offset;
 			goto emit;
 		} else {
-			const u64 range_end = offset + len;
+			const u64 range_end = offset + log_len;
 
 			/*
 			 * The offset of the file extent item we have just found
@@ -2656,11 +2662,13 @@ static int emit_fiemap_extent(struct fiemap_extent_info *fieinfo,
 			if (range_end <= cache_end)
 				return 0;
 
-			if (!(flags & (FIEMAP_EXTENT_DATA_COMPRESSED | FIEMAP_EXTENT_DELALLOC)))
+			if (!(flags & (FIEMAP_EXTENT_DATA_COMPRESSED | FIEMAP_EXTENT_DELALLOC))) {
 				phys += cache_end - offset;
+				phys_len -= cache_end - offset;
+			}
 
 			offset = cache_end;
-			len = range_end - cache_end;
+			log_len = range_end - cache_end;
 			goto emit;
 		}
 	}
@@ -2670,15 +2678,17 @@ static int emit_fiemap_extent(struct fiemap_extent_info *fieinfo,
 	 * 1) Their logical addresses are continuous
 	 *
 	 * 2) Their physical addresses are continuous
-	 *    So truly compressed (physical size smaller than logical size)
-	 *    extents won't get merged with each other
 	 *
 	 * 3) Share same flags
+	 *
+	 * 4) Not compressed
 	 */
-	if (cache->offset + cache->len  == offset &&
-	    cache->phys + cache->len == phys  &&
-	    cache->flags == flags) {
-		cache->len += len;
+	if (cache->offset + cache->log_len  == offset &&
+	    cache->phys + cache->log_len == phys  &&
+	    cache->flags == flags &&
+	    !(flags & FIEMAP_EXTENT_DATA_COMPRESSED)) {
+		cache->log_len += log_len;
+		cache->phys_len += phys_len;
 		return 0;
 	}
 
@@ -2695,7 +2705,7 @@ static int emit_fiemap_extent(struct fiemap_extent_info *fieinfo,
 		 * to miss it.
 		 */
 		entry = &cache->entries[cache->entries_size - 1];
-		cache->next_search_offset = entry->offset + entry->len;
+		cache->next_search_offset = entry->offset + entry->log_len;
 		cache->cached = false;
 
 		return BTRFS_FIEMAP_FLUSH_CACHE;
@@ -2704,7 +2714,8 @@ static int emit_fiemap_extent(struct fiemap_extent_info *fieinfo,
 	entry = &cache->entries[cache->entries_pos];
 	entry->offset = cache->offset;
 	entry->phys = cache->phys;
-	entry->len = cache->len;
+	entry->log_len = cache->log_len;
+	entry->phys_len = cache->phys_len;
 	entry->flags = cache->flags;
 	cache->entries_pos++;
 	cache->extents_mapped++;
@@ -2717,7 +2728,8 @@ static int emit_fiemap_extent(struct fiemap_extent_info *fieinfo,
 	cache->cached = true;
 	cache->offset = offset;
 	cache->phys = phys;
-	cache->len = len;
+	cache->log_len = log_len;
+	cache->phys_len = phys_len;
 	cache->flags = flags;
 
 	return 0;
@@ -2743,7 +2755,8 @@ static int emit_last_fiemap_cache(struct fiemap_extent_info *fieinfo,
 		return 0;
 
 	ret = fiemap_fill_next_extent(fieinfo, cache->offset, cache->phys,
-				      cache->len, 0, cache->flags);
+				      cache->log_len, cache->phys_len,
+				      cache->flags);
 	cache->cached = false;
 	if (ret > 0)
 		ret = 0;
@@ -2937,13 +2950,15 @@ static int fiemap_process_hole(struct btrfs_inode *inode,
 			}
 			ret = emit_fiemap_extent(fieinfo, cache, prealloc_start,
 						 disk_bytenr + extent_offset,
-						 prealloc_len, prealloc_flags);
+						 prealloc_len, prealloc_len,
+						 prealloc_flags);
 			if (ret)
 				return ret;
 			extent_offset += prealloc_len;
 		}
 
 		ret = emit_fiemap_extent(fieinfo, cache, delalloc_start, 0,
+					 delalloc_end + 1 - delalloc_start,
 					 delalloc_end + 1 - delalloc_start,
 					 FIEMAP_EXTENT_DELALLOC |
 					 FIEMAP_EXTENT_UNKNOWN);
@@ -2984,7 +2999,8 @@ static int fiemap_process_hole(struct btrfs_inode *inode,
 		}
 		ret = emit_fiemap_extent(fieinfo, cache, prealloc_start,
 					 disk_bytenr + extent_offset,
-					 prealloc_len, prealloc_flags);
+					 prealloc_len, prealloc_len,
+					 prealloc_flags);
 		if (ret)
 			return ret;
 	}
@@ -3130,6 +3146,7 @@ int extent_fiemap(struct btrfs_inode *inode, struct fiemap_extent_info *fieinfo,
 		u64 extent_offset = 0;
 		u64 extent_gen;
 		u64 disk_bytenr = 0;
+		u64 disk_size = 0;
 		u64 flags = 0;
 		int extent_type;
 		u8 compression;
@@ -3192,7 +3209,7 @@ int extent_fiemap(struct btrfs_inode *inode, struct fiemap_extent_info *fieinfo,
 			flags |= FIEMAP_EXTENT_DATA_INLINE;
 			flags |= FIEMAP_EXTENT_NOT_ALIGNED;
 			ret = emit_fiemap_extent(fieinfo, &cache, key.offset, 0,
-						 extent_len, flags);
+						 extent_len, extent_len, flags);
 		} else if (extent_type == BTRFS_FILE_EXTENT_PREALLOC) {
 			ret = fiemap_process_hole(inode, fieinfo, &cache,
 						  &delalloc_cached_state,
@@ -3207,6 +3224,7 @@ int extent_fiemap(struct btrfs_inode *inode, struct fiemap_extent_info *fieinfo,
 						  backref_ctx, 0, 0, 0,
 						  key.offset, extent_end - 1);
 		} else {
+			disk_size = btrfs_file_extent_disk_num_bytes(leaf, ei);
 			/* We have a regular extent. */
 			if (fieinfo->fi_extents_max) {
 				ret = btrfs_is_data_extent_shared(inode,
@@ -3221,7 +3239,9 @@ int extent_fiemap(struct btrfs_inode *inode, struct fiemap_extent_info *fieinfo,
 
 			ret = emit_fiemap_extent(fieinfo, &cache, key.offset,
 						 disk_bytenr + extent_offset,
-						 extent_len, flags);
+						 extent_len,
+						 disk_size - extent_offset,
+						 flags);
 		}
 
 		if (ret < 0) {
@@ -3259,7 +3279,7 @@ int extent_fiemap(struct btrfs_inode *inode, struct fiemap_extent_info *fieinfo,
 		prev_extent_end = range_end;
 	}
 
-	if (cache.cached && cache.offset + cache.len >= last_extent_end) {
+	if (cache.cached && cache.offset + cache.log_len >= last_extent_end) {
 		const u64 i_size = i_size_read(&inode->vfs_inode);
 
 		if (prev_extent_end < i_size) {
-- 
2.43.0