diff --git a/fs/btrfs/btrfs_inode.h b/fs/btrfs/btrfs_inode.h
index c652e19ad74e21..1093b00130bec9 100644
--- a/fs/btrfs/btrfs_inode.h
+++ b/fs/btrfs/btrfs_inode.h
@@ -189,8 +189,10 @@ struct btrfs_inode {
 	 */
 	u64 csum_bytes;
 
-	/* flags field from the on disk inode */
+	/* Backwards incompatible flags, lower half of inode_item::flags  */
 	u32 flags;
+	/* Read-only compatibility flags, upper half of inode_item::flags */
+	u32 ro_flags;
 
 	/*
 	 * Counters to keep track of the number of extent item's we may use due
@@ -348,6 +350,22 @@ struct btrfs_dio_private {
 	u8 csums[];
 };
 
+/*
+ * btrfs_inode_item stores flags in a u64, btrfs_inode stores them in two
+ * separate u32s. These two functions convert between the two representations.
+ */
+static inline u64 btrfs_inode_combine_flags(u32 flags, u32 ro_flags)
+{
+	return (flags | ((u64)ro_flags << 32));
+}
+
+static inline void btrfs_inode_split_flags(u64 inode_item_flags,
+					   u32 *flags, u32 *ro_flags)
+{
+	*flags = (u32)inode_item_flags;
+	*ro_flags = (u32)(inode_item_flags >> 32);
+}
+
 /* Array of bytes with variable length, hexadecimal format 0x1234 */
 #define CSUM_FMT				"0x%*phN"
 #define CSUM_FMT_VALUE(size, bytes)		size, bytes
diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index e5e53e592d4f99..459b2e54e35bd9 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -1484,20 +1484,20 @@ do {                                                                   \
 /*
  * Inode flags
  */
-#define BTRFS_INODE_NODATASUM		(1 << 0)
-#define BTRFS_INODE_NODATACOW		(1 << 1)
-#define BTRFS_INODE_READONLY		(1 << 2)
-#define BTRFS_INODE_NOCOMPRESS		(1 << 3)
-#define BTRFS_INODE_PREALLOC		(1 << 4)
-#define BTRFS_INODE_SYNC		(1 << 5)
-#define BTRFS_INODE_IMMUTABLE		(1 << 6)
-#define BTRFS_INODE_APPEND		(1 << 7)
-#define BTRFS_INODE_NODUMP		(1 << 8)
-#define BTRFS_INODE_NOATIME		(1 << 9)
-#define BTRFS_INODE_DIRSYNC		(1 << 10)
-#define BTRFS_INODE_COMPRESS		(1 << 11)
-
-#define BTRFS_INODE_ROOT_ITEM_INIT	(1 << 31)
+#define BTRFS_INODE_NODATASUM		(1U << 0)
+#define BTRFS_INODE_NODATACOW		(1U << 1)
+#define BTRFS_INODE_READONLY		(1U << 2)
+#define BTRFS_INODE_NOCOMPRESS		(1U << 3)
+#define BTRFS_INODE_PREALLOC		(1U << 4)
+#define BTRFS_INODE_SYNC		(1U << 5)
+#define BTRFS_INODE_IMMUTABLE		(1U << 6)
+#define BTRFS_INODE_APPEND		(1U << 7)
+#define BTRFS_INODE_NODUMP		(1U << 8)
+#define BTRFS_INODE_NOATIME		(1U << 9)
+#define BTRFS_INODE_DIRSYNC		(1U << 10)
+#define BTRFS_INODE_COMPRESS		(1U << 11)
+
+#define BTRFS_INODE_ROOT_ITEM_INIT	(1U << 31)
 
 #define BTRFS_INODE_FLAG_MASK						\
 	(BTRFS_INODE_NODATASUM |					\
@@ -1514,6 +1514,8 @@ do {                                                                   \
 	 BTRFS_INODE_COMPRESS |						\
 	 BTRFS_INODE_ROOT_ITEM_INIT)
 
+#define BTRFS_INODE_RO_FLAG_MASK					(0)
+
 struct btrfs_map_token {
 	struct extent_buffer *eb;
 	char *kaddr;
diff --git a/fs/btrfs/delayed-inode.c b/fs/btrfs/delayed-inode.c
index 257c1e18abd4fa..27be3150e5372b 100644
--- a/fs/btrfs/delayed-inode.c
+++ b/fs/btrfs/delayed-inode.c
@@ -1711,6 +1711,8 @@ static void fill_stack_inode_item(struct btrfs_trans_handle *trans,
 				  struct btrfs_inode_item *inode_item,
 				  struct inode *inode)
 {
+	u64 flags;
+
 	btrfs_set_stack_inode_uid(inode_item, i_uid_read(inode));
 	btrfs_set_stack_inode_gid(inode_item, i_gid_read(inode));
 	btrfs_set_stack_inode_size(inode_item, BTRFS_I(inode)->disk_i_size);
@@ -1723,7 +1725,9 @@ static void fill_stack_inode_item(struct btrfs_trans_handle *trans,
 				       inode_peek_iversion(inode));
 	btrfs_set_stack_inode_transid(inode_item, trans->transid);
 	btrfs_set_stack_inode_rdev(inode_item, inode->i_rdev);
-	btrfs_set_stack_inode_flags(inode_item, BTRFS_I(inode)->flags);
+	flags = btrfs_inode_combine_flags(BTRFS_I(inode)->flags,
+					  BTRFS_I(inode)->ro_flags);
+	btrfs_set_stack_inode_flags(inode_item, flags);
 	btrfs_set_stack_inode_block_group(inode_item, 0);
 
 	btrfs_set_stack_timespec_sec(&inode_item->atime,
@@ -1781,7 +1785,8 @@ int btrfs_fill_inode(struct inode *inode, u32 *rdev)
 				   btrfs_stack_inode_sequence(inode_item));
 	inode->i_rdev = 0;
 	*rdev = btrfs_stack_inode_rdev(inode_item);
-	BTRFS_I(inode)->flags = btrfs_stack_inode_flags(inode_item);
+	btrfs_inode_split_flags(btrfs_stack_inode_flags(inode_item),
+				&BTRFS_I(inode)->flags, &BTRFS_I(inode)->ro_flags);
 
 	inode->i_atime.tv_sec = btrfs_stack_timespec_sec(&inode_item->atime);
 	inode->i_atime.tv_nsec = btrfs_stack_timespec_nsec(&inode_item->atime);
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index e6eb20987351d6..be27cccea1a943 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -3639,7 +3639,8 @@ static int btrfs_read_locked_inode(struct inode *inode,
 	rdev = btrfs_inode_rdev(leaf, inode_item);
 
 	BTRFS_I(inode)->index_cnt = (u64)-1;
-	BTRFS_I(inode)->flags = btrfs_inode_flags(leaf, inode_item);
+	btrfs_inode_split_flags(btrfs_inode_flags(leaf, inode_item),
+				&BTRFS_I(inode)->flags, &BTRFS_I(inode)->ro_flags);
 
 cache_index:
 	/*
@@ -3770,6 +3771,7 @@ static void fill_inode_item(struct btrfs_trans_handle *trans,
 			    struct inode *inode)
 {
 	struct btrfs_map_token token;
+	u64 flags;
 
 	btrfs_init_map_token(&token, leaf);
 
@@ -3805,7 +3807,9 @@ static void fill_inode_item(struct btrfs_trans_handle *trans,
 	btrfs_set_token_inode_sequence(&token, item, inode_peek_iversion(inode));
 	btrfs_set_token_inode_transid(&token, item, trans->transid);
 	btrfs_set_token_inode_rdev(&token, item, inode->i_rdev);
-	btrfs_set_token_inode_flags(&token, item, BTRFS_I(inode)->flags);
+	flags = btrfs_inode_combine_flags(BTRFS_I(inode)->flags,
+					  BTRFS_I(inode)->ro_flags);
+	btrfs_set_token_inode_flags(&token, item, flags);
 	btrfs_set_token_inode_block_group(&token, item, 0);
 }
 
@@ -8904,6 +8908,7 @@ struct inode *btrfs_alloc_inode(struct super_block *sb)
 	ei->defrag_bytes = 0;
 	ei->disk_i_size = 0;
 	ei->flags = 0;
+	ei->ro_flags = 0;
 	ei->csum_bytes = 0;
 	ei->index_cnt = (u64)-1;
 	ei->dir_index = 0;
diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index 0ba98e08a0290d..8007364f064dd4 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -103,9 +103,10 @@ static unsigned int btrfs_mask_fsflags_for_type(struct inode *inode,
  * Export internal inode flags to the format expected by the FS_IOC_GETFLAGS
  * ioctl.
  */
-static unsigned int btrfs_inode_flags_to_fsflags(unsigned int flags)
+static unsigned int btrfs_inode_flags_to_fsflags(struct btrfs_inode *binode)
 {
 	unsigned int iflags = 0;
+	u32 flags = binode->flags;
 
 	if (flags & BTRFS_INODE_SYNC)
 		iflags |= FS_SYNC_FL;
@@ -200,7 +201,7 @@ int btrfs_fileattr_get(struct dentry *dentry, struct fileattr *fa)
 {
 	struct btrfs_inode *binode = BTRFS_I(d_inode(dentry));
 
-	fileattr_fill_flags(fa, btrfs_inode_flags_to_fsflags(binode->flags));
+	fileattr_fill_flags(fa, btrfs_inode_flags_to_fsflags(binode));
 	return 0;
 }
 
@@ -224,7 +225,7 @@ int btrfs_fileattr_set(struct user_namespace *mnt_userns,
 		return -EOPNOTSUPP;
 
 	fsflags = btrfs_mask_fsflags_for_type(inode, fa->flags);
-	old_fsflags = btrfs_inode_flags_to_fsflags(binode->flags);
+	old_fsflags = btrfs_inode_flags_to_fsflags(binode);
 	ret = check_fsflags(old_fsflags, fsflags);
 	if (ret)
 		return ret;
diff --git a/fs/btrfs/tree-checker.c b/fs/btrfs/tree-checker.c
index a8b2e0d2c02576..a4a9620957a654 100644
--- a/fs/btrfs/tree-checker.c
+++ b/fs/btrfs/tree-checker.c
@@ -24,6 +24,7 @@
 #include "compression.h"
 #include "volumes.h"
 #include "misc.h"
+#include "btrfs_inode.h"
 
 /*
  * Error message should follow the following format:
@@ -999,6 +1000,8 @@ static int check_inode_item(struct extent_buffer *leaf,
 	u32 valid_mask = (S_IFMT | S_ISUID | S_ISGID | S_ISVTX | 0777);
 	u32 mode;
 	int ret;
+	u32 flags;
+	u32 ro_flags;
 
 	ret = check_inode_key(leaf, key, slot);
 	if (unlikely(ret < 0))
@@ -1054,11 +1057,18 @@ static int check_inode_item(struct extent_buffer *leaf,
 			btrfs_inode_nlink(leaf, iitem));
 		return -EUCLEAN;
 	}
-	if (unlikely(btrfs_inode_flags(leaf, iitem) & ~BTRFS_INODE_FLAG_MASK)) {
+	btrfs_inode_split_flags(btrfs_inode_flags(leaf, iitem),
+				&flags, &ro_flags);
+	if (unlikely(flags & ~BTRFS_INODE_FLAG_MASK)) {
 		inode_item_err(leaf, slot,
-			       "unknown flags detected: 0x%llx",
-			       btrfs_inode_flags(leaf, iitem) &
-			       ~BTRFS_INODE_FLAG_MASK);
+			       "unknown incompat flags detected: 0x%x", flags);
+		return -EUCLEAN;
+	}
+	if (unlikely(!sb_rdonly(fs_info->sb) &&
+		     (ro_flags & ~BTRFS_INODE_RO_FLAG_MASK))) {
+		inode_item_err(leaf, slot,
+			       "unknown ro-compat flags detected on writeable mount: 0x%x",
+			       ro_flags);
 		return -EUCLEAN;
 	}
 	return 0;
diff --git a/fs/btrfs/tree-log.c b/fs/btrfs/tree-log.c
index cab451d19547ae..25d8616692e446 100644
--- a/fs/btrfs/tree-log.c
+++ b/fs/btrfs/tree-log.c
@@ -3913,6 +3913,7 @@ static void fill_inode_item(struct btrfs_trans_handle *trans,
 			    u64 logged_isize)
 {
 	struct btrfs_map_token token;
+	u64 flags;
 
 	btrfs_init_map_token(&token, leaf);
 
@@ -3962,7 +3963,9 @@ static void fill_inode_item(struct btrfs_trans_handle *trans,
 	btrfs_set_token_inode_sequence(&token, item, inode_peek_iversion(inode));
 	btrfs_set_token_inode_transid(&token, item, trans->transid);
 	btrfs_set_token_inode_rdev(&token, item, inode->i_rdev);
-	btrfs_set_token_inode_flags(&token, item, BTRFS_I(inode)->flags);
+	flags = btrfs_inode_combine_flags(BTRFS_I(inode)->flags,
+					  BTRFS_I(inode)->ro_flags);
+	btrfs_set_token_inode_flags(&token, item, flags);
 	btrfs_set_token_inode_block_group(&token, item, 0);
 }