btrfs: separate defrag and property compression

Add new value for compression to distinguish between defrag and
property. Previously, a single variable was used and this caused clashes
when the per-file 'compression' was set and a defrag -c was called.

The property-compression is loaded when the file is open, defrag will
overwrite the same variable and reset to 0 (ie. NONE) at when the file
defragmentaion is finished. That's considered a usability bug.

Now we won't touch the property value, use the defrag-compression. The
precedence of defrag is higher than for property (and whole-filesystem).
Signed-off-by: David Sterba <dsterba@suse.com>

fs/btrfs/btrfs_inode.h

@@ -182,6 +182,11 @@ struct btrfs_inode {
 	 * Cached values of inode properties
 	 */
 	unsigned prop_compress;		/* per-file compression algorithm */
+	/*
+	 * Force compression on the file using the defrag ioctl, could be
+	 * different from prop_compress and takes precedence if set
+	 */
+	unsigned defrag_compress;
 
 	struct btrfs_delayed_node *delayed_node;
 

fs/btrfs/inode.c

@@ -402,6 +402,9 @@ static inline int inode_need_compress(struct inode *inode, u64 start, u64 end)
 	/* bad compression ratios */
 	if (BTRFS_I(inode)->flags & BTRFS_INODE_NOCOMPRESS)
 		return 0;
+	/* defrag ioctl */
+	if (BTRFS_I(inode)->defrag_compress)
+		return 1;
 	if (btrfs_test_opt(fs_info, COMPRESS) ||
 	    BTRFS_I(inode)->flags & BTRFS_INODE_COMPRESS ||
 	    BTRFS_I(inode)->prop_compress)
@@ -511,7 +514,9 @@ static noinline void compress_file_range(struct inode *inode,
 			goto cont;
 		}
 
-		if (BTRFS_I(inode)->prop_compress)
+		if (BTRFS_I(inode)->defrag_compress)
+			compress_type = BTRFS_I(inode)->defrag_compress;
+		else if (BTRFS_I(inode)->prop_compress)
 			compress_type = BTRFS_I(inode)->prop_compress;
 
 		/*
@@ -9434,6 +9439,7 @@ struct inode *btrfs_alloc_inode(struct super_block *sb)
 
 	ei->runtime_flags = 0;
 	ei->prop_compress = BTRFS_COMPRESS_NONE;
+	ei->defrag_compress = BTRFS_COMPRESS_NONE;
 
 	ei->delayed_node = NULL;
 

fs/btrfs/ioctl.c

@@ -1371,7 +1371,7 @@ int btrfs_defrag_file(struct inode *inode, struct file *file,
 
 		inode_lock(inode);
 		if (range->flags & BTRFS_DEFRAG_RANGE_COMPRESS)
-			BTRFS_I(inode)->prop_compress = compress_type;
+			BTRFS_I(inode)->defrag_compress = compress_type;
 		ret = cluster_pages_for_defrag(inode, pages, i, cluster);
 		if (ret < 0) {
 			inode_unlock(inode);
@@ -1442,7 +1442,7 @@ int btrfs_defrag_file(struct inode *inode, struct file *file,
 out_ra:
 	if (range->flags & BTRFS_DEFRAG_RANGE_COMPRESS) {
 		inode_lock(inode);
-		BTRFS_I(inode)->prop_compress = BTRFS_COMPRESS_NONE;
+		BTRFS_I(inode)->defrag_compress = BTRFS_COMPRESS_NONE;
 		inode_unlock(inode);
 	}
 	if (!file)