Merge tag 'xfs-4.19-merge-6' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux

Pull xfs updates from Darrick Wong:
 "This is the second part of the XFS changes for 4.19.

  The biggest changes are the removal of buffer heads frm XFS, a massive
  reworking of the deferred transaction operations handling code, the
  removal of the long defunct barrier/nobarrier mount options, and the
  addition of a few more online repair functions.

  Summary:

   - Use extent maps to track pagecache page status instead of
     bufferhead state.

   - Refactor pagecache read and write paths to use the new iomap
     library functions, which enable us to drop the old bufferhead code
     for pagesize == blocksize filesystems.

   - Set up parallel per-block-per-page metadata to track subpage
     information that was tracked by buffer heads, which enables us to
     drop the old bufferhead code for pagesize > blocksize filesystems.

   - Tie a deferred ops control structure to a transaction so that we
     can take advantage of an upper-level dfops without having to plumb
     pointer passing through the code.

   - Refactor the deferred ops code to track deferred ops as part of the
     transaction structure (instead of as a separate data structure) so
     that we can simplify the scoping rules around defer_ops.

   - Refactor twisty delwri buffer submission code to avoid deadlocks.

   - Shorten and fix indenting problems in the scrub code.

   - Detect obviously bad summary counts at mount and fix them.

   - Directly associate deferred ops control structure with a
     transaction so that callers no longer have to manage it themselves.

   - Remove a couple of IRIX-era inode macros.

   - Remove the long-deprecated 'barrier' and 'nobarrier' mount options.

   - Clean up the inode fork structure a bit.

   - Check for bad fs summary counter values in the superblock.

   - Reduce COW fork lookups during writeback.

   - Refactor the deferred ops control structures into the transaction
     structure, thereby eliminating the need for transaction users to
     handle the deferred ops as a separate data structure.

   - Add the ability to repair AG headers online.

   - Fix a crash due to insufficient return value checking.

   - Various fixes and cleanups"

* tag 'xfs-4.19-merge-6' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux: (155 commits)
  xfs: fix a null pointer dereference in xfs_bmap_extents_to_btree
  xfs: remove b_last_holder & associated macros
  iomap: Switch to offset_in_page for clarity
  xfs: Close race between direct IO and xfs_break_layouts()
  xfs: repair the AGI
  xfs: repair the AGFL
  xfs: repair the AGF
  xfs: remove dead error handling code in xfs_dquot_disk_alloc()
  xfs: use WRITE_ONCE to update if_seq
  xfs: fix a comment in xfs_log_reserve
  xfs: only validate summary counts on primary superblock
  xfs: substitute spaces with tabs
  xfs: fold dfops into the transaction
  xfs: always defer agfl block frees
  xfs: pass transaction to xfs_defer_add()
  xfs: replace xfs_defer_ops ->dop_pending with on-stack list
  xfs: cancel dfops on xfs_defer_finish() error
  xfs: clean out superfluous dfops dop params/vars
  xfs: drop dop param from xfs_defer_op_type ->finish_item() callback
  xfs: automatic dfops inode relogging
  ...

119 files changed, 5673 insertions, 5334 deletions

diff --git a/Documentation/filesystems/xfs.txt b/Documentation/filesystems/xfs.txt
index 4d9ff0a7f8e1..a9ae82fb9d13 100644
--- a/Documentation/filesystems/xfs.txt
+++ b/Documentation/filesystems/xfs.txt
@@ -223,8 +223,6 @@ Deprecated Mount Options
 
   Name				Removal Schedule
   ----				----------------
-  barrier			no earlier than v4.15
-  nobarrier			no earlier than v4.15
 
 
 Removed Mount Options
@@ -236,6 +234,8 @@ Removed Mount Options
   ihashsize			v4.0
   irixsgid			v4.0
   osyncisdsync/osyncisosync	v4.0
+  barrier			v4.19
+  nobarrier			v4.19
 
 
 sysctls
diff --git a/fs/iomap.c b/fs/iomap.c
index 530670608fc8..009071e73bc0 100644
--- a/fs/iomap.c
+++ b/fs/iomap.c
@@ -17,6 +17,7 @@
 #include <linux/iomap.h>
 #include <linux/uaccess.h>
 #include <linux/gfp.h>
+#include <linux/migrate.h>
 #include <linux/mm.h>
 #include <linux/mm_inline.h>
 #include <linux/swap.h>
@@ -104,6 +105,138 @@ iomap_sector(struct iomap *iomap, loff_t pos)
 	return (iomap->addr + pos - iomap->offset) >> SECTOR_SHIFT;
 }
 
+static struct iomap_page *
+iomap_page_create(struct inode *inode, struct page *page)
+{
+	struct iomap_page *iop = to_iomap_page(page);
+
+	if (iop || i_blocksize(inode) == PAGE_SIZE)
+		return iop;
+
+	iop = kmalloc(sizeof(*iop), GFP_NOFS | __GFP_NOFAIL);
+	atomic_set(&iop->read_count, 0);
+	atomic_set(&iop->write_count, 0);
+	bitmap_zero(iop->uptodate, PAGE_SIZE / SECTOR_SIZE);
+	set_page_private(page, (unsigned long)iop);
+	SetPagePrivate(page);
+	return iop;
+}
+
+static void
+iomap_page_release(struct page *page)
+{
+	struct iomap_page *iop = to_iomap_page(page);
+
+	if (!iop)
+		return;
+	WARN_ON_ONCE(atomic_read(&iop->read_count));
+	WARN_ON_ONCE(atomic_read(&iop->write_count));
+	ClearPagePrivate(page);
+	set_page_private(page, 0);
+	kfree(iop);
+}
+
+/*
+ * Calculate the range inside the page that we actually need to read.
+ */
+static void
+iomap_adjust_read_range(struct inode *inode, struct iomap_page *iop,
+		loff_t *pos, loff_t length, unsigned *offp, unsigned *lenp)
+{
+	unsigned block_bits = inode->i_blkbits;
+	unsigned block_size = (1 << block_bits);
+	unsigned poff = offset_in_page(*pos);
+	unsigned plen = min_t(loff_t, PAGE_SIZE - poff, length);
+	unsigned first = poff >> block_bits;
+	unsigned last = (poff + plen - 1) >> block_bits;
+	unsigned end = offset_in_page(i_size_read(inode)) >> block_bits;
+
+	/*
+	 * If the block size is smaller than the page size we need to check the
+	 * per-block uptodate status and adjust the offset and length if needed
+	 * to avoid reading in already uptodate ranges.
+	 */
+	if (iop) {
+		unsigned int i;
+
+		/* move forward for each leading block marked uptodate */
+		for (i = first; i <= last; i++) {
+			if (!test_bit(i, iop->uptodate))
+				break;
+			*pos += block_size;
+			poff += block_size;
+			plen -= block_size;
+			first++;
+		}
+
+		/* truncate len if we find any trailing uptodate block(s) */
+		for ( ; i <= last; i++) {
+			if (test_bit(i, iop->uptodate)) {
+				plen -= (last - i + 1) * block_size;
+				last = i - 1;
+				break;
+			}
+		}
+	}
+
+	/*