Merge tag 'xfs-for-linus-4.9-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/dgc/linux-xfs

Pull xfs and iomap updates from Dave Chinner:
 "The main things in this update are the iomap-based DAX infrastructure,
  an XFS delalloc rework, and a chunk of fixes to how log recovery
  schedules writeback to prevent spurious corruption detections when
  recovery of certain items was not required.

  The other main chunk of code is some preparation for the upcoming
  reflink functionality. Most of it is generic and cleanups that stand
  alone, but they were ready and reviewed so are in this pull request.

  Speaking of reflink, I'm currently planning to send you another pull
  request next week containing all the new reflink functionality. I'm
  working through a similar process to the last cycle, where I sent the
  reverse mapping code in a separate request because of how large it
  was. The reflink code merge is even bigger than reverse mapping, so
  I'll be doing the same thing again....

  Summary for this update:

   - change of XFS mailing list to linux-xfs@vger.kernel.org

   - iomap-based DAX infrastructure w/ XFS and ext2 support

   - small iomap fixes and additions

   - more efficient XFS delayed allocation infrastructure based on iomap

   - a rework of log recovery writeback scheduling to ensure we don't
     fail recovery when trying to replay items that are already on disk

   - some preparation patches for upcoming reflink support

   - configurable error handling fixes and documentation

   - aio access time update race fixes for XFS and
     generic_file_read_iter"

* tag 'xfs-for-linus-4.9-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/dgc/linux-xfs: (40 commits)
  fs: update atime before I/O in generic_file_read_iter
  xfs: update atime before I/O in xfs_file_dio_aio_read
  ext2: fix possible integer truncation in ext2_iomap_begin
  xfs: log recovery tracepoints to track current lsn and buffer submission
  xfs: update metadata LSN in buffers during log recovery
  xfs: don't warn on buffers not being recovered due to LSN
  xfs: pass current lsn to log recovery buffer validation
  xfs: rework log recovery to submit buffers on LSN boundaries
  xfs: quiesce the filesystem after recovery on readonly mount
  xfs: remote attribute blocks aren't really userdata
  ext2: use iomap to implement DAX
  ext2: stop passing buffer_head to ext2_get_blocks
  xfs: use iomap to implement DAX
  xfs: refactor xfs_setfilesize
  xfs: take the ilock shared if possible in xfs_file_iomap_begin
  xfs: fix locking for DAX writes
  dax: provide an iomap based fault handler
  dax: provide an iomap based dax read/write path
  dax: don't pass buffer_head to copy_user_dax
  dax: don't pass buffer_head to dax_insert_mapping
  ...

4 files changed, 152 insertions, 26 deletions

diff --git a/fs/ext2/Kconfig b/fs/ext2/Kconfig
index c634874e12d9..36bea5adcaba 100644
--- a/fs/ext2/Kconfig
+++ b/fs/ext2/Kconfig
@@ -1,5 +1,6 @@
 config EXT2_FS
 	tristate "Second extended fs support"
+	select FS_IOMAP if FS_DAX
 	help
 	  Ext2 is a standard Linux file system for hard disks.
 
diff --git a/fs/ext2/ext2.h b/fs/ext2/ext2.h
index 06af2f92226c..37e2be784ac7 100644
--- a/fs/ext2/ext2.h
+++ b/fs/ext2/ext2.h
@@ -814,6 +814,7 @@ extern const struct file_operations ext2_file_operations;
 /* inode.c */
 extern const struct address_space_operations ext2_aops;
 extern const struct address_space_operations ext2_nobh_aops;
+extern struct iomap_ops ext2_iomap_ops;
 
 /* namei.c */
 extern const struct inode_operations ext2_dir_inode_operations;
diff --git a/fs/ext2/file.c b/fs/ext2/file.c
index 5efeefe17abb..423cc01c9d41 100644
--- a/fs/ext2/file.c
+++ b/fs/ext2/file.c
@@ -22,11 +22,59 @@
 #include <linux/pagemap.h>
 #include <linux/dax.h>
 #include <linux/quotaops.h>
+#include <linux/iomap.h>
+#include <linux/uio.h>
 #include "ext2.h"
 #include "xattr.h"
 #include "acl.h"
 
 #ifdef CONFIG_FS_DAX
+static ssize_t ext2_dax_read_iter(struct kiocb *iocb, struct iov_iter *to)
+{
+	struct inode *inode = iocb->ki_filp->f_mapping->host;
+	ssize_t ret;
+
+	if (!iov_iter_count(to))
+		return 0; /* skip atime */
+
+	inode_lock_shared(inode);
+	ret = iomap_dax_rw(iocb, to, &ext2_iomap_ops);
+	inode_unlock_shared(inode);
+
+	file_accessed(iocb->ki_filp);
+	return ret;
+}
+
+static ssize_t ext2_dax_write_iter(struct kiocb *iocb, struct iov_iter *from)
+{
+	struct file *file = iocb->ki_filp;
+	struct inode *inode = file->f_mapping->host;
+	ssize_t ret;
+
+	inode_lock(inode);
+	ret = generic_write_checks(iocb, from);
+	if (ret <= 0)
+		goto out_unlock;
+	ret = file_remove_privs(file);
+	if (ret)
+		goto out_unlock;
+	ret = file_update_time(file);
+	if (ret)
+		goto out_unlock;
+
+	ret = iomap_dax_rw(iocb, from, &ext2_iomap_ops);
+	if (ret > 0 && iocb->ki_pos > i_size_read(inode)) {
+		i_size_write(inode, iocb->ki_pos);
+		mark_inode_dirty(inode);
+	}
+
+out_unlock:
+	inode_unlock(inode);
+	if (ret > 0)
+		ret = generic_write_sync(iocb, ret);
+	return ret;
+}
+
 /*
  * The lock ordering for ext2 DAX fault paths is:
  *
@@ -51,7 +99,7 @@ static int ext2_dax_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
 	}
 	down_read(&ei->dax_sem);
 
-	ret = dax_fault(vma, vmf, ext2_get_block);
+	ret = iomap_dax_fault(vma, vmf, &ext2_iomap_ops);
 
 	up_read(&ei->dax_sem);
 	if (vmf->flags & FAULT_FLAG_WRITE)
@@ -156,14 +204,28 @@ int ext2_fsync(struct file *file, loff_t start, loff_t end, int datasync)
 	return ret;
 }
 
-/*
- * We have mostly NULL's here: the current defaults are ok for
- * the ext2 filesystem.
- */
+static ssize_t ext2_file_read_iter(struct kiocb *iocb, struct iov_iter *to)
+{
+#ifdef CONFIG_FS_DAX
+	if (IS_DAX(iocb->ki_filp->f_mapping->host))
+		return ext2_dax_read_iter(iocb, to);
+#endif
+	return generic_file_read_iter(iocb, to);
+}
+
+static ssize_t ext2_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
+{
+#ifdef CONFIG_FS_DAX
+	if (IS_DAX(iocb->ki_filp->f_mapping->host))
+		return ext2_dax_write_iter(iocb, from);
+#endif
+	return generic_file_write_iter(iocb, from);
+}
+
 const struct file_operations ext2_file_operations = {
 	.llseek		= generic_file_llseek,
-	.read_iter	= generic_file_read_iter,
-	.write_iter	= generic_file_write_iter,
+	.read_iter	= ext2_file_read_iter,
+	.write_iter	= ext2_file_write_iter,
 	.unlocked_ioctl = ext2_ioctl,
 #ifdef CONFIG_COMPAT
 	.compat_ioctl	= ext2_compat_ioctl,
diff --git a/fs/ext2/inode.c b/fs/ext2/inode.c
index 303ae2bb269a..1e72d425fd3b 100644
--- a/fs/ext2/inode.c
+++ b/fs/ext2/inode.c
@@ -32,6 +32,7 @@
 #include <linux/buffer_head.h>
 #include <linux/mpage.h>
 #include <linux/fiemap.h>
+#include <linux/iomap.h>
 #include <linux/namei.h>
 #include <linux/uio.h>
 #include "ext2.h"
@@ -618,7 +619,7 @@ static void ext2_splice_branch(struct inode *inode,
  */
 static int ext2_get_blocks(struct inode *inode,
 			   sector_t iblock, unsigned long maxblocks,
-			   struct buffer_head *bh_result,
+			   u32 *bno, bool *new, bool *boundary,
 			   int create)
 {
 	int err = -EIO;
@@ -644,7 +645,6 @@ static int ext2_get_blocks(struct inode *inode,
 	/* Simplest case - block found, no allocation needed */
 	if (!partial) {
 		first_block = le32_to_cpu(chain[depth - 1].key);
-		clear_buffer_new(bh_result); /* What's this do? */
 		count++;
 		/*map more blocks*/
 		while (count < maxblocks && count <= blocks_to_boundary) {
@@ -699,7 +699,6 @@ static int ext2_get_blocks(struct inode *inode,
 			mutex_unlock(&ei->truncate_mutex);
 			if (err)
 				goto cleanup;
-			clear_buffer_new(bh_result);
 			goto got_it;
 		}
 	}
@@ -755,15 +754,16 @@ static int ext2_get_blocks(struct inode *inode,
 			mutex_unlock(&ei->truncate_mutex);
 			goto cleanup;
 		}
-	} else
-		set_buffer_new(bh_result);
+	} else {
+		*new = true;
+	}
 
 	ext2_splice_branch(inode, iblock, partial, indirect_blks, count);
 	mutex_unlock(&ei->truncate_mutex);
 got_it:
-	map_bh(bh_result, inode->i_sb, le32_to_cpu(chain[depth-1].key));
+	*bno = le32_to_cpu(chain[depth-1].key);
 	if (count > blocks_to_boundary)
-		set_buffer_boundary(bh_result);
+		*boundary = true;
 	err = count;
 	/* Clean up and exit */
 	partial = chain + depth - 1;	/* the whole chain */
@@ -775,19 +775,82 @@ cleanup:
 	return err;
 }
 
-int ext2_get_block(struct inode *inode, sector_t iblock, struct buffer_head *bh_result, int create)
+int ext2_get_block(struct inode *inode, sector_t iblock,
+		struct buffer_head *bh_result, int create)
 {
 	unsigned max_blocks = bh_result->b_size >> inode->i_blkbits;
-	int ret = ext2_get_blocks(inode, iblock, max_blocks,
-			      bh_result, create);
-	if (ret > 0) {
-		bh_result->b_size = (ret << inode->i_blkbits);
-		ret = 0;
+	bool new = false, boundary = false;
+	u32 bno;
+	int ret;
+
+	ret = ext2_get_blocks(inode, iblock, max_blocks, &bno, &new, &boundary,
+			create);
+	if (ret <= 0)
+		return ret;
+
+	map_bh(bh_result, inode->i_sb, bno);
+	bh_result->b_size = (ret << inode->i_blkbits);
+	if (new)
+		set_buffer_new(bh_result);
+	if (boundary)
+		set_buffer_boundary(bh_result);
+	return 0;
+
+}
+
+#ifdef CONFIG_FS_DAX
+static int ext2_iomap_begin(struct inode *inode, loff_t offset, loff_t length,
+		unsigned flags, struct iomap *iomap)
+{
+	unsigned int blkbits = inode->i_blkbits;
+	unsigned long first_block = offset >> blkbits;
+	unsigned long max_blocks = (length + (1 << blkbits) - 1) >> blkbits;
+	bool new = false, boundary = false;
+	u32 bno;
+	int ret;
+
+	ret = ext2_get_blocks(inode, first_block, max_blocks,
+			&bno, &new, &boundary, flags & IOMAP_WRITE);
+	if (ret < 0)
+		return ret;
+
+	iomap->flags = 0;
+	iomap->bdev = inode->i_sb->s_bdev;
+	iomap->offset = (u64)first_block << blkbits;
+
+	if (ret == 0) {
+		iomap->type = IOMAP_HOLE;
+		iomap->blkno = IOMAP_NULL_BLOCK;
+		iomap->length = 1 << blkbits;
+	} else {
+		iomap->type = IOMAP_MAPPED;
+		iomap->blkno = (sector_t)bno << (blkbits - 9);
+		iomap->length = (u64)ret << blkbits;
+		iomap->flags |= IOMAP_F_MERGED;
 	}
-	return ret;
 
+	if (new)
+		iomap->flags |= IOMAP_F_NEW;
+	return 0;
 }
 
+static int
+ext2_iomap_end(struct inode *inode, loff_t offset, loff_t length,
+		ssize_t written, unsigned flags, struct iomap *iomap)
+{
+	if (iomap->type == IOMAP_MAPPED &&
+	    written < length &&
+	    (flags & IOMAP_WRITE))
+		ext2_write_failed(inode->i_mapping, offset + length);
+	return 0;
+}
+
+struct iomap_ops ext2_iomap_ops = {
+	.iomap_begin		= ext2_iomap_begin,
+	.iomap_end		= ext2_iomap_end,
+};
+#endif /* CONFIG_FS_DAX */
+
 int ext2_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
 		u64 start, u64 len)
 {
@@ -873,11 +936,10 @@ ext2_direct_IO(struct kiocb *iocb, struct iov_iter *iter)
 	loff_t offset = iocb->ki_pos;
 	ssize_t ret;
 
-	if (IS_DAX(inode))
-		ret = dax_do_io(iocb, inode, iter, ext2_get_block, NULL,
-				DIO_LOCKING);
-	else
-		ret = blockdev_direct_IO(iocb, inode, iter, ext2_get_block);
+	if (WARN_ON_ONCE(IS_DAX(inode)))
+		return -EIO;
+
+	ret = blockdev_direct_IO(iocb, inode, iter, ext2_get_block);
 	if (ret < 0 && iov_iter_rw(iter) == WRITE)
 		ext2_write_failed(mapping, offset + count);
 	return ret;