hfsplus: optimize fsync

Avoid doing unessecary work in fsync.  Do nothing unless the inode
was marked dirty, and only write the various metadata inodes out if
they contain any dirty state from this inode.  This is archived by
adding three new dirty bits to the hfsplus-specific inode which are
set in the correct places.

Signed-off-by: Christoph Hellwig <hch@tuxera.com>
diff --git a/fs/hfsplus/catalog.c b/fs/hfsplus/catalog.c
index 8af45fc..0aa40b3 100644
--- a/fs/hfsplus/catalog.c
+++ b/fs/hfsplus/catalog.c
@@ -227,7 +227,8 @@
 
 	dir->i_size++;
 	dir->i_mtime = dir->i_ctime = CURRENT_TIME_SEC;
-	mark_inode_dirty(dir);
+	hfsplus_mark_inode_dirty(dir, HFSPLUS_I_CAT_DIRTY);
+
 	hfs_find_exit(&fd);
 	return 0;
 
@@ -308,7 +309,7 @@
 
 	dir->i_size--;
 	dir->i_mtime = dir->i_ctime = CURRENT_TIME_SEC;
-	mark_inode_dirty(dir);
+	hfsplus_mark_inode_dirty(dir, HFSPLUS_I_CAT_DIRTY);
 out:
 	hfs_find_exit(&fd);
 
@@ -353,7 +354,6 @@
 		goto out;
 	dst_dir->i_size++;
 	dst_dir->i_mtime = dst_dir->i_ctime = CURRENT_TIME_SEC;
-	mark_inode_dirty(dst_dir);
 
 	/* finally remove the old entry */
 	hfsplus_cat_build_key(sb, src_fd.search_key, src_dir->i_ino, src_name);
@@ -365,7 +365,6 @@
 		goto out;
 	src_dir->i_size--;
 	src_dir->i_mtime = src_dir->i_ctime = CURRENT_TIME_SEC;
-	mark_inode_dirty(src_dir);
 
 	/* remove old thread entry */
 	hfsplus_cat_build_key(sb, src_fd.search_key, cnid, NULL);
@@ -387,6 +386,9 @@
 		goto out;
 	}
 	err = hfs_brec_insert(&dst_fd, &entry, entry_size);
+
+	hfsplus_mark_inode_dirty(dst_dir, HFSPLUS_I_CAT_DIRTY);
+	hfsplus_mark_inode_dirty(src_dir, HFSPLUS_I_CAT_DIRTY);
 out:
 	hfs_bnode_put(dst_fd.bnode);
 	hfs_find_exit(&src_fd);
diff --git a/fs/hfsplus/extents.c b/fs/hfsplus/extents.c
index 06b4fc3..b1127ef 100644
--- a/fs/hfsplus/extents.c
+++ b/fs/hfsplus/extents.c
@@ -108,6 +108,14 @@
 				fd->entryoffset, fd->entrylength);
 		hip->extent_state &= ~HFSPLUS_EXT_DIRTY;
 	}
+
+	/*
+	 * We can't just use hfsplus_mark_inode_dirty here, because we
+	 * also get called from hfsplus_write_inode, which should not
+	 * redirty the inode.  Instead the callers have to be careful
+	 * to explicily mark the inode dirty, too.
+	 */
+	set_bit(HFSPLUS_I_EXT_DIRTY, &hip->flags);
 }
 
 static void hfsplus_ext_write_extent_locked(struct inode *inode)
@@ -197,6 +205,7 @@
 	struct hfsplus_inode_info *hip = HFSPLUS_I(inode);
 	int res = -EIO;
 	u32 ablock, dblock, mask;
+	int was_dirty = 0;
 	int shift;
 
 	/* Convert inode block to disk allocation block */
@@ -223,14 +232,20 @@
 		return -EIO;
 
 	mutex_lock(&hip->extents_lock);
+
+	/*
+	 * hfsplus_ext_read_extent will write out a cached extent into
+	 * the extents btree.  In that case we may have to mark the inode
+	 * dirty even for a pure read of an extent here.
+	 */
+	was_dirty = (hip->extent_state & HFSPLUS_EXT_DIRTY);
 	res = hfsplus_ext_read_extent(inode, ablock);
-	if (!res) {
-		dblock = hfsplus_ext_find_block(hip->cached_extents,
-						ablock - hip->cached_start);
-	} else {
+	if (res) {
 		mutex_unlock(&hip->extents_lock);
 		return -EIO;
 	}
+	dblock = hfsplus_ext_find_block(hip->cached_extents,
+					ablock - hip->cached_start);
 	mutex_unlock(&hip->extents_lock);
 
 done:
@@ -242,8 +257,9 @@
 		hip->phys_size += sb->s_blocksize;
 		hip->fs_blocks++;
 		inode_add_bytes(inode, sb->s_blocksize);
-		mark_inode_dirty(inode);
 	}
+	if (create || was_dirty)
+		mark_inode_dirty(inode);
 	return 0;
 }
 
@@ -438,7 +454,7 @@
 	mutex_unlock(&hip->extents_lock);
 	if (!res) {
 		hip->alloc_blocks += len;
-		mark_inode_dirty(inode);
+		hfsplus_mark_inode_dirty(inode, HFSPLUS_I_ALLOC_DIRTY);
 	}
 	return res;
 
@@ -529,5 +545,5 @@
 	hip->phys_size = inode->i_size;
 	hip->fs_blocks = (inode->i_size + sb->s_blocksize - 1) >> sb->s_blocksize_bits;
 	inode_set_bytes(inode, hip->fs_blocks << sb->s_blocksize_bits);
-	mark_inode_dirty(inode);
+	hfsplus_mark_inode_dirty(inode, HFSPLUS_I_ALLOC_DIRTY);
 }
diff --git a/fs/hfsplus/hfsplus_fs.h b/fs/hfsplus/hfsplus_fs.h
index 9889d00..65c698f 100644
--- a/fs/hfsplus/hfsplus_fs.h
+++ b/fs/hfsplus/hfsplus_fs.h
@@ -157,6 +157,11 @@
 #define HFSPLUS_SB_HFSX		3
 #define HFSPLUS_SB_CASEFOLD	4
 
+static inline struct hfsplus_sb_info *HFSPLUS_SB(struct super_block *sb)
+{
+	return sb->s_fs_info;
+}
+
 
 struct hfsplus_inode_info {
 	atomic_t opencnt;
@@ -205,10 +210,31 @@
 #define HFSPLUS_EXT_NEW		0x0002
 
 #define HFSPLUS_I_RSRC		0	/* represents a resource fork */
+#define HFSPLUS_I_CAT_DIRTY	1	/* has changes in the catalog tree */
+#define HFSPLUS_I_EXT_DIRTY	2	/* has changes in the extent tree */
+#define HFSPLUS_I_ALLOC_DIRTY	3	/* has changes in the allocation file */
 
 #define HFSPLUS_IS_RSRC(inode) \
 	test_bit(HFSPLUS_I_RSRC, &HFSPLUS_I(inode)->flags)
 
+static inline struct hfsplus_inode_info *HFSPLUS_I(struct inode *inode)
+{
+	return list_entry(inode, struct hfsplus_inode_info, vfs_inode);
+}
+
+/*
+ * Mark an inode dirty, and also mark the btree in which the
+ * specific type of metadata is stored.
+ * For data or metadata that gets written back by into the catalog btree
+ * by hfsplus_write_inode a plain mark_inode_dirty call is enough.
+ */
+static inline void hfsplus_mark_inode_dirty(struct inode *inode,
+		unsigned int flag)
+{
+	set_bit(flag, &HFSPLUS_I(inode)->flags);
+	mark_inode_dirty(inode);
+}
+
 struct hfs_find_data {
 	/* filled by caller */
 	hfsplus_btree_key *search_key;
@@ -397,17 +423,6 @@
 int hfsplus_submit_bio(struct block_device *bdev, sector_t sector,
 		void *data, int rw);
 
-/* access macros */
-static inline struct hfsplus_sb_info *HFSPLUS_SB(struct super_block *sb)
-{
-	return sb->s_fs_info;
-}
-
-static inline struct hfsplus_inode_info *HFSPLUS_I(struct inode *inode)
-{
-	return list_entry(inode, struct hfsplus_inode_info, vfs_inode);
-}
-
 /* time macros */
 #define __hfsp_mt2ut(t)		(be32_to_cpu(t) - 2082844800U)
 #define __hfsp_ut2mt(t)		(cpu_to_be32(t + 2082844800U))
diff --git a/fs/hfsplus/inode.c b/fs/hfsplus/inode.c
index 0946e2c..bf6535b 100644
--- a/fs/hfsplus/inode.c
+++ b/fs/hfsplus/inode.c
@@ -307,8 +307,9 @@
 int hfsplus_file_fsync(struct file *file, int datasync)
 {
 	struct inode *inode = file->f_mapping->host;
+	struct hfsplus_inode_info *hip = HFSPLUS_I(inode);
 	struct hfsplus_sb_info *sbi = HFSPLUS_SB(inode->i_sb);
-	int error, error2;
+	int error = 0, error2;
 
 	/*
 	 * Sync inode metadata into the catalog and extent trees.
@@ -318,13 +319,21 @@
 	/*
 	 * And explicitly write out the btrees.
 	 */
-	error = filemap_write_and_wait(sbi->cat_tree->inode->i_mapping);
-	error2 = filemap_write_and_wait(sbi->ext_tree->inode->i_mapping);
-	if (!error)
-		error = error2;
-	error2 = filemap_write_and_wait(sbi->alloc_file->i_mapping);
-	if (!error)
-		error = error2;
+	if (test_and_clear_bit(HFSPLUS_I_CAT_DIRTY, &hip->flags))
+		error = filemap_write_and_wait(sbi->cat_tree->inode->i_mapping);
+
+	if (test_and_clear_bit(HFSPLUS_I_EXT_DIRTY, &hip->flags)) {
+		error2 = filemap_write_and_wait(sbi->ext_tree->inode->i_mapping);
+		if (!error)
+			error = error2;
+	}
+
+	if (test_and_clear_bit(HFSPLUS_I_ALLOC_DIRTY, &hip->flags)) {
+		error2 = filemap_write_and_wait(sbi->alloc_file->i_mapping);
+		if (!error)
+			error = error2;
+	}
+
 	return error;
 }
 
@@ -590,6 +599,8 @@
 		hfs_bnode_write(fd.bnode, &entry, fd.entryoffset,
 					 sizeof(struct hfsplus_cat_file));
 	}
+
+	set_bit(HFSPLUS_I_CAT_DIRTY, &HFSPLUS_I(inode)->flags);
 out:
 	hfs_find_exit(&fd);
 	return 0;
diff --git a/fs/hfsplus/ioctl.c b/fs/hfsplus/ioctl.c
index 40a85a3d..f5a7224 100644
--- a/fs/hfsplus/ioctl.c
+++ b/fs/hfsplus/ioctl.c
@@ -147,9 +147,11 @@
 			res = -ERANGE;
 	} else
 		res = -EOPNOTSUPP;
-	if (!res)
+	if (!res) {
 		hfs_bnode_write(fd.bnode, &entry, fd.entryoffset,
 				sizeof(struct hfsplus_cat_file));
+		hfsplus_mark_inode_dirty(inode, HFSPLUS_I_CAT_DIRTY);
+	}
 out:
 	hfs_find_exit(&fd);
 	return res;
diff --git a/fs/hfsplus/super.c b/fs/hfsplus/super.c
index 9854237..0366501 100644
--- a/fs/hfsplus/super.c
+++ b/fs/hfsplus/super.c
@@ -472,7 +472,7 @@
 				   &str, sbi->hidden_dir);
 		mutex_unlock(&sbi->vh_mutex);
 
-		mark_inode_dirty(sbi->hidden_dir);
+		hfsplus_mark_inode_dirty(sbi->hidden_dir, HFSPLUS_I_CAT_DIRTY);
 	}
 out:
 	unload_nls(sbi->nls);