Btrfs: set default max_inline to 8KiB instead of 8MiB

8MiB is way too large and likely set by mistake. This is not
a significant issue as in practice the max amount of data
added to an inline extent is also limited by the page cache
and btree leaf sizes.

Signed-off-by: Filipe David Borba Manana <fdmanana@gmail.com>
Reviewed-by: David Sterba <dsterba@suse.cz>
Signed-off-by: David Sterba <dsterba@suse.cz>

fs/btrfs/ctree.h

@@ -2089,6 +2089,7 @@ struct btrfs_ioctl_defrag_range_args {
 #define	BTRFS_MOUNT_CHANGE_INODE_CACHE	(1 << 24)
 
 #define BTRFS_DEFAULT_COMMIT_INTERVAL	(30)
+#define BTRFS_DEFAULT_MAX_INLINE	(8192)
 
 #define btrfs_clear_opt(o, opt)		((o) &= ~BTRFS_MOUNT_##opt)
 #define btrfs_set_opt(o, opt)		((o) |= BTRFS_MOUNT_##opt)

fs/btrfs/disk-io.c

@@ -2260,7 +2260,7 @@ int open_ctree(struct super_block *sb,
 	atomic_set(&fs_info->qgroup_op_seq, 0);
 	atomic64_set(&fs_info->tree_mod_seq, 0);
 	fs_info->sb = sb;
-	fs_info->max_inline = 8192 * 1024;
+	fs_info->max_inline = BTRFS_DEFAULT_MAX_INLINE;
 	fs_info->metadata_ratio = 0;
 	fs_info->defrag_inodes = RB_ROOT;
 	fs_info->free_chunk_space = 0;

fs/btrfs/super.c

@@ -1014,7 +1014,7 @@ static int btrfs_show_options(struct seq_file *seq, struct dentry *dentry)
 		seq_puts(seq, ",nodatacow");
 	if (btrfs_test_opt(root, NOBARRIER))
 		seq_puts(seq, ",nobarrier");
-	if (info->max_inline != 8192 * 1024)
+	if (info->max_inline != BTRFS_DEFAULT_MAX_INLINE)
 		seq_printf(seq, ",max_inline=%llu", info->max_inline);
 	if (info->alloc_start != 0)
 		seq_printf(seq, ",alloc_start=%llu", info->alloc_start);