Merge tag 'for-5.8-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux

Pull btrfs updates from David Sterba:
 "Highlights:

   - speedup dead root detection during orphan cleanup, eg. when there
     are many deleted subvolumes waiting to be cleaned, the trees are
     now looked up in radix tree instead of a O(N^2) search

   - snapshot creation with inherited qgroup will mark the qgroup
     inconsistent, requires a rescan

   - send will emit file capabilities after chown, this produces a
     stream that does not need postprocessing to set the capabilities
     again

   - direct io ported to iomap infrastructure, cleaned up and simplified
     code, notably removing last use of struct buffer_head in btrfs code

  Core changes:

   - factor out backreference iteration, to be used by ordinary
     backreferences and relocation code

   - improved global block reserve utilization
      * better logic to serialize requests
      * increased maximum available for unlink
      * improved handling on large pages (64K)

   - direct io cleanups and fixes
      * simplify layering, where cloned bios were unnecessarily created
        for some cases
      * error handling fixes (submit, endio)
      * remove repair worker thread, used to avoid deadlocks during
        repair

   - refactored block group reading code, preparatory work for new type
     of block group storage that should improve mount time on large
     filesystems

  Cleanups:

   - cleaned up (and slightly sped up) set/get helpers for metadata data
     structure members

   - root bit REF_COWS got renamed to SHAREABLE to reflect the that the
     blocks of the tree get shared either among subvolumes or with the
     relocation trees

  Fixes:

   - when subvolume deletion fails due to ENOSPC, the filesystem is not
     turned read-only

   - device scan deals with devices from other filesystems that changed
     ownership due to overwrite (mkfs)

   - fix a race between scrub and block group removal/allocation

   - fix long standing bug of a runaway balance operation, printing the
     same line to the syslog, caused by a stale status bit on a reloc
     tree that prevented progress

   - fix corrupt log due to concurrent fsync of inodes with shared
     extents

   - fix space underflow for NODATACOW and buffered writes when it for
     some reason needs to fallback to COW mode"

* tag 'for-5.8-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux: (133 commits)
  btrfs: fix space_info bytes_may_use underflow during space cache writeout
  btrfs: fix space_info bytes_may_use underflow after nocow buffered write
  btrfs: fix wrong file range cleanup after an error filling dealloc range
  btrfs: remove redundant local variable in read_block_for_search
  btrfs: open code key_search
  btrfs: split btrfs_direct_IO to read and write part
  btrfs: remove BTRFS_INODE_READDIO_NEED_LOCK
  fs: remove dio_end_io()
  btrfs: switch to iomap_dio_rw() for dio
  iomap: remove lockdep_assert_held()
  iomap: add a filesystem hook for direct I/O bio submission
  fs: export generic_file_buffered_read()
  btrfs: turn space cache writeout failure messages into debug messages
  btrfs: include error on messages about failure to write space/inode caches
  btrfs: remove useless 'fail_unlock' label from btrfs_csum_file_blocks()
  btrfs: do not ignore error from btrfs_next_leaf() when inserting checksums
  btrfs: make checksum item extension more efficient
  btrfs: fix corrupt log due to concurrent fsync of inodes with shared extents
  btrfs: unexport btrfs_compress_set_level()
  btrfs: simplify iget helpers
  ...

1 files changed, 112 insertions, 111 deletions

diff --git a/fs/btrfs/struct-funcs.c b/fs/btrfs/struct-funcs.c
index 73f7987143df..079b059818e9 100644
--- a/fs/btrfs/struct-funcs.c
+++ b/fs/btrfs/struct-funcs.c
@@ -17,151 +17,152 @@ static inline void put_unaligned_le8(u8 val, void *p)
        *(u8 *)p = val;
 }
 
+static bool check_setget_bounds(const struct extent_buffer *eb,
+				const void *ptr, unsigned off, int size)
+{
+	const unsigned long member_offset = (unsigned long)ptr + off;
+
+	if (member_offset > eb->len) {
+		btrfs_warn(eb->fs_info,
+	"bad eb member start: ptr 0x%lx start %llu member offset %lu size %d",
+			(unsigned long)ptr, eb->start, member_offset, size);
+		return false;
+	}
+	if (member_offset + size > eb->len) {
+		btrfs_warn(eb->fs_info,
+	"bad eb member end: ptr 0x%lx start %llu member offset %lu size %d",
+			(unsigned long)ptr, eb->start, member_offset, size);
+		return false;
+	}
+
+	return true;
+}
+
 /*
- * this is some deeply nasty code.
+ * Macro templates that define helpers to read/write extent buffer data of a
+ * given size, that are also used via ctree.h for access to item members by
+ * specialized helpers.
  *
- * The end result is that anyone who #includes ctree.h gets a
- * declaration for the btrfs_set_foo functions and btrfs_foo functions,
- * which are wrappers of btrfs_set_token_#bits functions and
- * btrfs_get_token_#bits functions, which are defined in this file.
+ * Generic helpers:
+ * - btrfs_set_8 (for 8/16/32/64)
+ * - btrfs_get_8 (for 8/16/32/64)
  *
- * These setget functions do all the extent_buffer related mapping
- * required to efficiently read and write specific fields in the extent
- * buffers.  Every pointer to metadata items in btrfs is really just
- * an unsigned long offset into the extent buffer which has been
- * cast to a specific type.  This gives us all the gcc type checking.
+ * Generic helpers with a token (cached address of the most recently accessed
+ * page):
+ * - btrfs_set_token_8 (for 8/16/32/64)
+ * - btrfs_get_token_8 (for 8/16/32/64)
  *
- * The extent buffer api is used to do the page spanning work required to
- * have a metadata blocksize different from the page size.
+ * The set/get functions handle data spanning two pages transparently, in case
+ * metadata block size is larger than page.  Every pointer to metadata items is
+ * an offset into the extent buffer page array, cast to a specific type.  This
+ * gives us all the type checking.
  *
- * There are 2 variants defined, one with a token pointer and one without.
+ * The extent buffer pages stored in the array pages do not form a contiguous
+ * phyusical range, but the API functions assume the linear offset to the range
+ * from 0 to metadata node size.
  */
 
 #define DEFINE_BTRFS_SETGET_BITS(bits)					\
-u##bits btrfs_get_token_##bits(const struct extent_buffer *eb,		\
-			       const void *ptr, unsigned long off,	\
-			       struct btrfs_map_token *token)		\
+u##bits btrfs_get_token_##bits(struct btrfs_map_token *token,		\
+			       const void *ptr, unsigned long off)	\
 {									\
-	unsigned long part_offset = (unsigned long)ptr;			\
-	unsigned long offset = part_offset + off;			\
-	void *p;							\
-	int err;							\
-	char *kaddr;							\
-	unsigned long map_start;					\
-	unsigned long map_len;						\
-	int size = sizeof(u##bits);					\
-	u##bits res;							\
+	const unsigned long member_offset = (unsigned long)ptr + off;	\
+	const unsigned long idx = member_offset >> PAGE_SHIFT;		\
+	const unsigned long oip = offset_in_page(member_offset);	\
+	const int size = sizeof(u##bits);				\
+	u8 lebytes[sizeof(u##bits)];					\
+	const int part = PAGE_SIZE - oip;				\
 									\
 	ASSERT(token);							\
-	ASSERT(token->eb == eb);					\
-									\
-	if (token->kaddr && token->offset <= offset &&			\
-	   (token->offset + PAGE_SIZE >= offset + size)) {	\
-		kaddr = token->kaddr;					\
-		p = kaddr + part_offset - token->offset;		\
-		res = get_unaligned_le##bits(p + off);			\
-		return res;						\
+	ASSERT(token->kaddr);						\
+	ASSERT(check_setget_bounds(token->eb, ptr, off, size));		\
+	if (token->offset <= member_offset &&				\
+	    member_offset + size <= token->offset + PAGE_SIZE) {	\
+		return get_unaligned_le##bits(token->kaddr + oip);	\
 	}								\
-	err = map_private_extent_buffer(eb, offset, size,		\
-					&kaddr, &map_start, &map_len);	\
-	if (err) {							\
-		__le##bits leres;					\
+	token->kaddr = page_address(token->eb->pages[idx]);		\
+	token->offset = idx << PAGE_SHIFT;				\
+	if (oip + size <= PAGE_SIZE)					\
+		return get_unaligned_le##bits(token->kaddr + oip);	\
 									\
-		read_extent_buffer(eb, &leres, offset, size);		\
-		return le##bits##_to_cpu(leres);			\
-	}								\
-	p = kaddr + part_offset - map_start;				\
-	res = get_unaligned_le##bits(p + off);				\
-	token->kaddr = kaddr;						\
-	token->offset = map_start;					\
-	return res;							\
+	memcpy(lebytes, token->kaddr + oip, part);			\
+	token->kaddr = page_address(token->eb->pages[idx + 1]);		\
+	token->offset = (idx + 1) << PAGE_SHIFT;			\
+	memcpy(lebytes + part, token->kaddr, size - part);		\
+	return get_unaligned_le##bits(lebytes);				\
 }									\
 u##bits btrfs_get_##bits(const struct extent_buffer *eb,		\
 			 const void *ptr, unsigned long off)		\
 {									\
-	unsigned long part_offset = (unsigned long)ptr;			\
-	unsigned long offset = part_offset + off;			\
-	void *p;							\
-	int err;							\
-	char *kaddr;							\
-	unsigned long map_start;					\
-	unsigned long map_len;						\
-	int size = sizeof(u##bits);					\
-	u##bits res;							\
+	const unsigned long member_offset = (unsigned long)ptr + off;	\
+	const unsigned long oip = offset_in_page(member_offset);	\
+	const unsigned long idx = member_offset >> PAGE_SHIFT;		\
+	char *kaddr = page_address(eb->pages[idx]);			\
+	const int size = sizeof(u##bits);				\
+	const int part = PAGE_SIZE - oip;				\
+	u8 lebytes[sizeof(u##bits)];					\
 									\
-	err = map_private_extent_buffer(eb, offset, size,		\
-					&kaddr, &map_start, &map_len);	\
-	if (err) {							\
-		__le##bits leres;					\
+	ASSERT(check_setget_bounds(eb, ptr, off, size));		\
+	if (oip + size <= PAGE_SIZE)					\
+		return get_unaligned_le##bits(kaddr + oip);		\
 									\
-		read_extent_buffer(eb, &leres, offset, size);		\
-		return le##bits##_to_cpu(leres);			\
-	}								\
-	p = kaddr + part_offset - map_start;				\
-	res = get_unaligned_le##bits(p + off);				\
-	return res;							\
+	memcpy(lebytes, kaddr + oip, part);				\
+	kaddr = page_address(eb->pages[idx + 1]);			\
+	memcpy(lebytes + part, kaddr, size - part);			\
+	return get_unaligned_le##bits(lebytes);				\
 }									\
-void btrfs_set_token_##bits(struct extent_buffer *eb,			\
+void btrfs_set_token_##bits(struct btrfs_map_token *token,		\
 			    const void *ptr, unsigned long off,		\
-			    u##bits val,				\
-			    struct btrfs_map_token *token)		\
+			    u##bits val)				\
 {									\
-	unsigned long part_offset = (unsigned long)ptr;			\
-	unsigned long offset = part_offset + off;			\
-	void *p;							\
-	int err;							\
-	char *kaddr;							\
-	unsigned long map_start;					\
-	unsigned long map_len;						\
-	int size = sizeof(u##bits);					\
+	const unsigned long member_offset = (unsigned long)ptr + off;	\
+	const unsigned long idx = member_offset >> PAGE_SHIFT;		\
+	const unsigned long oip = offset_in_page(member_offset);	\
+	const int size = sizeof(u##bits);				\
+	u8 lebytes[sizeof(u##bits)];					\
+	const int part = PAGE_SIZE - oip;				\
 									\
 	ASSERT(token);							\
-	ASSERT(token->eb == eb);					\
-									\
-	if (token->kaddr && token->offset <= offset &&			\
-	   (token->offset + PAGE_SIZE >= offset + size)) {	\
-		kaddr = token->kaddr;					\
-		p = kaddr + part_offset - token->offset;		\
-		put_unaligned_le##bits(val, p + off);			\
+	ASSERT(token->kaddr);						\
+	ASSERT(check_setget_bounds(token->eb, ptr, off, size));		\
+	if (token->offset <= member_offset &&				\
+	    member_offset + size <= token->offset + PAGE_SIZE) {	\
+		put_unaligned_le##bits(val, token->kaddr + oip);	\
 		return;							\
 	}								\
-	err = map_private_extent_buffer(eb, offset, size,		\
-			&kaddr, &map_start, &map_len);			\
-	if (err) {							\
-		__le##bits val2;					\
-									\
-		val2 = cpu_to_le##bits(val);				\
-		write_extent_buffer(eb, &val2, offset, size);		\
+	token->kaddr = page_address(token->eb->pages[idx]);		\
+	token->offset = idx << PAGE_SHIFT;				\
+	if (oip + size <= PAGE_SIZE) {					\
+		put_unaligned_le##bits(val, token->kaddr + oip);	\
 		return;							\
 	}								\
-	p = kaddr + part_offset - map_start;				\
-	put_unaligned_le##bits(val, p + off);				\
-	token->kaddr = kaddr;						\
-	token->offset = map_start;					\
+	put_unaligned_le##bits(val, lebytes);				\
+	memcpy(token->kaddr + oip, lebytes, part);			\
+	token->kaddr = page_address(token->eb->pages[idx + 1]);		\
+	token->offset = (idx + 1) << PAGE_SHIFT;			\
+	memcpy(token->kaddr, lebytes + part, size - part);		\
 }									\
-void btrfs_set_##bits(struct extent_buffer *eb, void *ptr,		\
+void btrfs_set_##bits(const struct extent_buffer *eb, void *ptr,	\
 		      unsigned long off, u##bits val)			\
 {									\
-	unsigned long part_offset = (unsigned long)ptr;			\
-	unsigned long offset = part_offset + off;			\
-	void *p;							\
-	int err;							\
-	char *kaddr;							\
-	unsigned long map_start;					\
-	unsigned long map_len;						\
-	int size = sizeof(u##bits);					\
-									\
-	err = map_private_extent_buffer(eb, offset, size,		\
-			&kaddr, &map_start, &map_len);			\
-	if (err) {							\
-		__le##bits val2;					\
+	const unsigned long member_offset = (unsigned long)ptr + off;	\
+	const unsigned long oip = offset_in_page(member_offset);	\
+	const unsigned long idx = member_offset >> PAGE_SHIFT;		\
+	char *kaddr = page_address(eb->pages[idx]);			\
+	const int size = sizeof(u##bits);				\
+	const int part = PAGE_SIZE - oip;				\
+	u8 lebytes[sizeof(u##bits)];					\
 									\
-		val2 = cpu_to_le##bits(val);				\
-		write_extent_buffer(eb, &val2, offset, size);		\
+	ASSERT(check_setget_bounds(eb, ptr, off, size));		\
+	if (oip + size <= PAGE_SIZE) {					\
+		put_unaligned_le##bits(val, kaddr + oip);		\
 		return;							\
 	}								\
-	p = kaddr + part_offset - map_start;				\
-	put_unaligned_le##bits(val, p + off);				\
+									\
+	put_unaligned_le##bits(val, lebytes);				\
+	memcpy(kaddr + oip, lebytes, part);				\
+	kaddr = page_address(eb->pages[idx + 1]);			\
+	memcpy(kaddr, lebytes + part, size - part);			\
 }
 
 DEFINE_BTRFS_SETGET_BITS(8)