1 files changed, 218 insertions, 187 deletions

diff --git a/fs/ext4/file.c b/fs/ext4/file.c
index 7ac0a81bd371..7a8b30932189 100644
--- a/fs/ext4/file.c
+++ b/fs/ext4/file.c
@@ -131,7 +131,7 @@ static ssize_t ext4_file_read_iter(struct kiocb *iocb, struct iov_iter *to)
 {
 	struct inode *inode = file_inode(iocb->ki_filp);
 
-	if (unlikely(ext4_forced_shutdown(EXT4_SB(inode->i_sb))))
+	if (unlikely(ext4_forced_shutdown(inode->i_sb)))
 		return -EIO;
 
 	if (!iov_iter_count(to))
@@ -147,6 +147,17 @@ static ssize_t ext4_file_read_iter(struct kiocb *iocb, struct iov_iter *to)
 	return generic_file_read_iter(iocb, to);
 }
 
+static ssize_t ext4_file_splice_read(struct file *in, loff_t *ppos,
+				     struct pipe_inode_info *pipe,
+				     size_t len, unsigned int flags)
+{
+	struct inode *inode = file_inode(in);
+
+	if (unlikely(ext4_forced_shutdown(inode->i_sb)))
+		return -EIO;
+	return filemap_splice_read(in, ppos, pipe, len, flags);
+}
+
 /*
  * Called when an inode is released. Note that this is different
  * from ext4_file_open: open gets called at every open, but release
@@ -163,7 +174,7 @@ static int ext4_release_file(struct inode *inode, struct file *filp)
 			(atomic_read(&inode->i_writecount) == 1) &&
 			!EXT4_I(inode)->i_reserved_data_blocks) {
 		down_write(&EXT4_I(inode)->i_data_sem);
-		ext4_discard_preallocations(inode, 0);
+		ext4_discard_preallocations(inode);
 		up_write(&EXT4_I(inode)->i_data_sem);
 	}
 	if (is_dx(inode) && filp->private_data)
@@ -202,8 +213,9 @@ ext4_extending_io(struct inode *inode, loff_t offset, size_t len)
 	return false;
 }
 
-/* Is IO overwriting allocated and initialized blocks? */
-static bool ext4_overwrite_io(struct inode *inode, loff_t pos, loff_t len)
+/* Is IO overwriting allocated or initialized blocks? */
+static bool ext4_overwrite_io(struct inode *inode,
+			      loff_t pos, loff_t len, bool *unwritten)
 {
 	struct ext4_map_blocks map;
 	unsigned int blkbits = inode->i_blkbits;
@@ -217,12 +229,15 @@ static bool ext4_overwrite_io(struct inode *inode, loff_t pos, loff_t len)
 	blklen = map.m_len;
 
 	err = ext4_map_blocks(NULL, inode, &map, 0);
+	if (err != blklen)
+		return false;
 	/*
 	 * 'err==len' means that all of the blocks have been preallocated,
-	 * regardless of whether they have been initialized or not. To exclude
-	 * unwritten extents, we need to check m_flags.
+	 * regardless of whether they have been initialized or not. We need to
+	 * check m_flags to distinguish the unwritten extents.
 	 */
-	return err == blklen && (map.m_flags & EXT4_MAP_MAPPED);
+	*unwritten = !(map.m_flags & EXT4_MAP_MAPPED);
+	return true;
 }
 
 static ssize_t ext4_generic_write_checks(struct kiocb *iocb,
@@ -281,95 +296,48 @@ static ssize_t ext4_buffered_write_iter(struct kiocb *iocb,
 	if (ret <= 0)
 		goto out;
 
-	current->backing_dev_info = inode_to_bdi(inode);
 	ret = generic_perform_write(iocb, from);
-	current->backing_dev_info = NULL;
 
 out:
 	inode_unlock(inode);
-	if (likely(ret > 0)) {
-		iocb->ki_pos += ret;
-		ret = generic_write_sync(iocb, ret);
-	}
-
-	return ret;
+	if (unlikely(ret <= 0))
+		return ret;
+	return generic_write_sync(iocb, ret);
 }
 
 static ssize_t ext4_handle_inode_extension(struct inode *inode, loff_t offset,
-					   ssize_t written, size_t count)
+					   ssize_t written, ssize_t count)
 {
 	handle_t *handle;
-	bool truncate = false;
-	u8 blkbits = inode->i_blkbits;
-	ext4_lblk_t written_blk, end_blk;
-	int ret;
-
-	/*
-	 * Note that EXT4_I(inode)->i_disksize can get extended up to
-	 * inode->i_size while the I/O was running due to writeback of delalloc
-	 * blocks. But, the code in ext4_iomap_alloc() is careful to use
-	 * zeroed/unwritten extents if this is possible; thus we won't leave
-	 * uninitialized blocks in a file even if we didn't succeed in writing
-	 * as much as we intended.
-	 */
-	WARN_ON_ONCE(i_size_read(inode) < EXT4_I(inode)->i_disksize);
-	if (offset + count <= EXT4_I(inode)->i_disksize) {
-		/*
-		 * We need to ensure that the inode is removed from the orphan
-		 * list if it has been added prematurely, due to writeback of
-		 * delalloc blocks.
-		 */
-		if (!list_empty(&EXT4_I(inode)->i_orphan) && inode->i_nlink) {
-			handle = ext4_journal_start(inode, EXT4_HT_INODE, 2);
-
-			if (IS_ERR(handle)) {
-				ext4_orphan_del(NULL, inode);
-				return PTR_ERR(handle);
-			}
-
-			ext4_orphan_del(handle, inode);
-			ext4_journal_stop(handle);
-		}
-
-		return written;
-	}
-
-	if (written < 0)
-		goto truncate;
 
+	lockdep_assert_held_write(&inode->i_rwsem);
 	handle = ext4_journal_start(inode, EXT4_HT_INODE, 2);
-	if (IS_ERR(handle)) {
-		written = PTR_ERR(handle);
-		goto truncate;
-	}
+	if (IS_ERR(handle))
+		return PTR_ERR(handle);
 
 	if (ext4_update_inode_size(inode, offset + written)) {
-		ret = ext4_mark_inode_dirty(handle, inode);
+		int ret = ext4_mark_inode_dirty(handle, inode);
 		if (unlikely(ret)) {
-			written = ret;
 			ext4_journal_stop(handle);
-			goto truncate;
+			return ret;
 		}
 	}
 
-	/*
-	 * We may need to truncate allocated but not written blocks beyond EOF.
-	 */
-	written_blk = ALIGN(offset + written, 1 << blkbits);
-	end_blk = ALIGN(offset + count, 1 << blkbits);
-	if (written_blk < end_blk && ext4_can_truncate(inode))
-		truncate = true;
-
-	/*
-	 * Remove the inode from the orphan list if it has been extended and
-	 * everything went OK.
-	 */
-	if (!truncate && inode->i_nlink)
+	if ((written == count) && inode->i_nlink)
 		ext4_orphan_del(handle, inode);
 	ext4_journal_stop(handle);
 
-	if (truncate) {
-truncate:
+	return written;
+}
+
+/*
+ * Clean up the inode after DIO or DAX extending write has completed and the
+ * inode size has been updated using ext4_handle_inode_extension().
+ */
+static void ext4_inode_extension_cleanup(struct inode *inode, bool need_trunc)
+{
+	lockdep_assert_held_write(&inode->i_rwsem);
+	if (need_trunc) {
 		ext4_truncate_failed_write(inode);
 		/*
 		 * If the truncate operation failed early, then the inode may
@@ -378,9 +346,29 @@ truncate:
 		 */
 		if (inode->i_nlink)
 			ext4_orphan_del(NULL, inode);
+		return;
 	}
+	/*
+	 * If i_disksize got extended either due to writeback of delalloc
+	 * blocks or extending truncate while the DIO was running we could fail
+	 * to cleanup the orphan list in ext4_handle_inode_extension(). Do it
+	 * now.
+	 */
+	if (ext4_inode_orphan_tracked(inode) && inode->i_nlink) {
+		handle_t *handle = ext4_journal_start(inode, EXT4_HT_INODE, 2);
 
-	return written;
+		if (IS_ERR(handle)) {
+			/*
+			 * The write has successfully completed. Not much to
+			 * do with the error here so just cleanup the orphan
+			 * list and hope for the best.
+			 */
+			ext4_orphan_del(NULL, inode);
+			return;
+		}
+		ext4_orphan_del(handle, inode);
+		ext4_journal_stop(handle);
+	}
 }
 
 static int ext4_dio_write_end_io(struct kiocb *iocb, ssize_t size,
@@ -389,31 +377,29 @@ static int ext4_dio_write_end_io(struct kiocb *iocb, ssize_t size,
 	loff_t pos = iocb->ki_pos;
 	struct inode *inode = file_inode(iocb->ki_filp);
 
-	if (error)
-		return error;
 
-	if (size && flags & IOMAP_DIO_UNWRITTEN) {
+	if (!error && size && (flags & IOMAP_DIO_UNWRITTEN) &&
+			(iocb->ki_flags & IOCB_ATOMIC))
+		error = ext4_convert_unwritten_extents_atomic(NULL, inode, pos,
+							      size);
+	else if (!error && size && flags & IOMAP_DIO_UNWRITTEN)
 		error = ext4_convert_unwritten_extents(NULL, inode, pos, size);
-		if (error < 0)
-			return error;
-	}
+	if (error)
+		return error;
 	/*
-	 * If we are extending the file, we have to update i_size here before
-	 * page cache gets invalidated in iomap_dio_rw(). Otherwise racing
-	 * buffered reads could zero out too much from page cache pages. Update
-	 * of on-disk size will happen later in ext4_dio_write_iter() where
-	 * we have enough information to also perform orphan list handling etc.
-	 * Note that we perform all extending writes synchronously under
-	 * i_rwsem held exclusively so i_size update is safe here in that case.
-	 * If the write was not extending, we cannot see pos > i_size here
-	 * because operations reducing i_size like truncate wait for all
-	 * outstanding DIO before updating i_size.
+	 * Note that EXT4_I(inode)->i_disksize can get extended up to
+	 * inode->i_size while the I/O was running due to writeback of delalloc
+	 * blocks. But the code in ext4_iomap_alloc() is careful to use
+	 * zeroed/unwritten extents if this is possible; thus we won't leave
+	 * uninitialized blocks in a file even if we didn't succeed in writing
+	 * as much as we intended. Also we can race with truncate or write
+	 * expanding the file so we have to be a bit careful here.
 	 */
-	pos += size;
-	if (pos > i_size_read(inode))
-		i_size_write(inode, pos);
-
-	return 0;
+	if (pos + size <= READ_ONCE(EXT4_I(inode)->i_disksize) &&
+	    pos + size <= i_size_read(inode))
+		return 0;
+	error = ext4_handle_inode_extension(inode, pos, size, size);
+	return error < 0 ? error : 0;
 }
 
 static const struct iomap_dio_ops ext4_dio_write_ops = {
@@ -431,17 +417,23 @@ static const struct iomap_dio_ops ext4_dio_write_ops = {
  * - For extending writes case we don't take the shared lock, since it requires
  *   updating inode i_disksize and/or orphan handling with exclusive lock.
  *
- * - shared locking will only be true mostly with overwrites. Otherwise we will
- *   switch to exclusive i_rwsem lock.
+ * - shared locking will only be true mostly with overwrites, including
+ *   initialized blocks and unwritten blocks. For overwrite unwritten blocks
+ *   we protect splitting extents by i_data_sem in ext4_inode_info, so we can
+ *   also release exclusive i_rwsem lock.
+ *
+ * - Otherwise we will switch to exclusive i_rwsem lock.
  */
 static ssize_t ext4_dio_write_checks(struct kiocb *iocb, struct iov_iter *from,
-				     bool *ilock_shared, bool *extend)
+				     bool *ilock_shared, bool *extend,
+				     bool *unwritten, int *dio_flags)
 {
 	struct file *file = iocb->ki_filp;
 	struct inode *inode = file_inode(file);
 	loff_t offset;
 	size_t count;
 	ssize_t ret;
+	bool overwrite, unaligned_io;
 
 restart:
 	ret = ext4_generic_write_checks(iocb, from);
@@ -450,16 +442,25 @@ restart:
 
 	offset = iocb->ki_pos;
 	count = ret;
-	if (ext4_extending_io(inode, offset, count))
-		*extend = true;
+
+	unaligned_io = ext4_unaligned_io(inode, from, offset);
+	*extend = ext4_extending_io(inode, offset, count);
+	overwrite = ext4_overwrite_io(inode, offset, count, unwritten);
+
 	/*
-	 * Determine whether the IO operation will overwrite allocated
-	 * and initialized blocks.
-	 * We need exclusive i_rwsem for changing security info
-	 * in file_modified().
+	 * Determine whether we need to upgrade to an exclusive lock. This is
+	 * required to change security info in file_modified(), for extending
+	 * I/O, any form of non-overwrite I/O, and unaligned I/O to unwritten
+	 * extents (as partial block zeroing may be required).
+	 *
+	 * Note that unaligned writes are allowed under shared lock so long as
+	 * they are pure overwrites. Otherwise, concurrent unaligned writes risk
+	 * data corruption due to partial block zeroing in the dio layer, and so
+	 * the I/O must occur exclusively.
 	 */
-	if (*ilock_shared && (!IS_NOSEC(inode) || *extend ||
-	     !ext4_overwrite_io(inode, offset, count))) {
+	if (*ilock_shared &&
+	    ((!IS_NOSEC(inode) || *extend || !overwrite ||
+	     (unaligned_io && *unwritten)))) {
 		if (iocb->ki_flags & IOCB_NOWAIT) {
 			ret = -EAGAIN;
 			goto out;
@@ -470,6 +471,23 @@ restart:
 		goto restart;
 	}
 
+	/*
+	 * Now that locking is settled, determine dio flags and exclusivity
+	 * requirements. We don't use DIO_OVERWRITE_ONLY because we enforce
+	 * behavior already. The inode lock is already held exclusive if the
+	 * write is non-overwrite or extending, so drain all outstanding dio and
+	 * set the force wait dio flag.
+	 */
+	if (!*ilock_shared && (unaligned_io || *extend)) {
+		if (iocb->ki_flags & IOCB_NOWAIT) {
+			ret = -EAGAIN;
+			goto out;
+		}
+		if (unaligned_io && (!overwrite || *unwritten))
+			inode_dio_wait(inode);
+		*dio_flags = IOMAP_DIO_FORCE_WAIT;
+	}
+
 	ret = file_modified(file);
 	if (ret < 0)
 		goto out;
@@ -491,18 +509,11 @@ static ssize_t ext4_dio_write_iter(struct kiocb *iocb, struct iov_iter *from)
 	loff_t offset = iocb->ki_pos;
 	size_t count = iov_iter_count(from);
 	const struct iomap_ops *iomap_ops = &ext4_iomap_ops;
-	bool extend = false, unaligned_io = false;
+	bool extend = false, unwritten = false;
 	bool ilock_shared = true;
+	int dio_flags = 0;
 
 	/*
-	 * We initially start with shared inode lock unless it is
-	 * unaligned IO which needs exclusive lock anyways.
-	 */
-	if (ext4_unaligned_io(inode, from, offset)) {
-		unaligned_io = true;
-		ilock_shared = false;
-	}
-	/*
 	 * Quick check here without any i_rwsem lock to see if it is extending
 	 * IO. A more reliable check is done in ext4_dio_write_checks() with
 	 * proper locking in place.
@@ -534,38 +545,23 @@ static ssize_t ext4_dio_write_iter(struct kiocb *iocb, struct iov_iter *from)
 		return ext4_buffered_write_iter(iocb, from);
 	}
 
-	ret = ext4_dio_write_checks(iocb, from, &ilock_shared, &extend);
-	if (ret <= 0)
-		return ret;
-
-	/* if we're going to block and IOCB_NOWAIT is set, return -EAGAIN */
-	if ((iocb->ki_flags & IOCB_NOWAIT) && (unaligned_io || extend)) {
-		ret = -EAGAIN;
-		goto out;
-	}
 	/*
-	 * Make sure inline data cannot be created anymore since we are going
-	 * to allocate blocks for DIO. We know the inode does not have any
-	 * inline data now because ext4_dio_supported() checked for that.
+	 * Prevent inline data from being created since we are going to allocate
+	 * blocks for DIO. We know the inode does not currently have inline data
+	 * because ext4_should_use_dio() checked for it, but we have to clear
+	 * the state flag before the write checks because a lock cycle could
+	 * introduce races with other writers.
 	 */
 	ext4_clear_inode_state(inode, EXT4_STATE_MAY_INLINE_DATA);
 
+	ret = ext4_dio_write_checks(iocb, from, &ilock_shared, &extend,
+				    &unwritten, &dio_flags);
+	if (ret <= 0)
+		return ret;
+
 	offset = iocb->ki_pos;
 	count = ret;
 
-	/*
-	 * Unaligned direct IO must be serialized among each other as zeroing
-	 * of partial blocks of two competing unaligned IOs can result in data
-	 * corruption.
-	 *
-	 * So we make sure we don't allow any unaligned IO in flight.
-	 * For IOs where we need not wait (like unaligned non-AIO DIO),
-	 * below inode_dio_wait() may anyway become a no-op, since we start
-	 * with exclusive lock.
-	 */
-	if (unaligned_io)
-		inode_dio_wait(inode);
-
 	if (extend) {
 		handle = ext4_journal_start(inode, EXT4_HT_INODE, 2);
 		if (IS_ERR(handle)) {
@@ -574,24 +570,27 @@ static ssize_t ext4_dio_write_iter(struct kiocb *iocb, struct iov_iter *from)
 		}
 
 		ret = ext4_orphan_add(handle, inode);
-		if (ret) {
-			ext4_journal_stop(handle);
-			goto out;
-		}
-
 		ext4_journal_stop(handle);
+		if (ret)
+			goto out;
 	}
 
-	if (ilock_shared)
+	if (ilock_shared && !unwritten)
 		iomap_ops = &ext4_iomap_overwrite_ops;
 	ret = iomap_dio_rw(iocb, from, iomap_ops, &ext4_dio_write_ops,
-			   (unaligned_io || extend) ? IOMAP_DIO_FORCE_WAIT : 0,
-			   NULL, 0);
+			   dio_flags, NULL, 0);
 	if (ret == -ENOTBLK)
 		ret = 0;
-
-	if (extend)
-		ret = ext4_handle_inode_extension(inode, offset, ret, count);
+	if (extend) {
+		/*
+		 * We always perform extending DIO write synchronously so by
+		 * now the IO is completed and ext4_handle_inode_extension()
+		 * was called. Cleanup the inode in case of error or race with
+		 * writeback of delalloc blocks.
+		 */
+		WARN_ON_ONCE(ret == -EIOCBQUEUED);
+		ext4_inode_extension_cleanup(inode, ret < 0);
+	}
 
 out:
 	if (ilock_shared)
@@ -603,6 +602,13 @@ out:
 		ssize_t err;
 		loff_t endbyte;
 
+		/*
+		 * There is no support for atomic writes on buffered-io yet,
+		 * we should never fallback to buffered-io for DIO atomic
+		 * writes.
+		 */
+		WARN_ON_ONCE(iocb->ki_flags & IOCB_ATOMIC);
+
 		offset = iocb->ki_pos;
 		err = ext4_buffered_write_iter(iocb, from);
 		if (err < 0)
@@ -672,8 +678,10 @@ ext4_dax_write_iter(struct kiocb *iocb, struct iov_iter *from)
 
 	ret = dax_iomap_rw(iocb, from, &ext4_iomap_ops);
 
-	if (extend)
+	if (extend) {
 		ret = ext4_handle_inode_extension(inode, offset, ret, count);
+		ext4_inode_extension_cleanup(inode, ret < (ssize_t)count);
+	}
 out:
 	inode_unlock(inode);
 	if (ret > 0)
@@ -685,15 +693,30 @@ out:
 static ssize_t
 ext4_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
 {
+	int ret;
 	struct inode *inode = file_inode(iocb->ki_filp);
 
-	if (unlikely(ext4_forced_shutdown(EXT4_SB(inode->i_sb))))
-		return -EIO;
+	ret = ext4_emergency_state(inode->i_sb);
+	if (unlikely(ret))
+		return ret;
 
 #ifdef CONFIG_FS_DAX
 	if (IS_DAX(inode))
 		return ext4_dax_write_iter(iocb, from);
 #endif
+
+	if (iocb->ki_flags & IOCB_ATOMIC) {
+		size_t len = iov_iter_count(from);
+
+		if (len < EXT4_SB(inode->i_sb)->s_awu_min ||
+		    len > EXT4_SB(inode->i_sb)->s_awu_max)
+			return -EINVAL;
+
+		ret = generic_atomic_write_valid(iocb, from);
+		if (ret)
+			return ret;
+	}
+
 	if (iocb->ki_flags & IOCB_DIRECT)
 		return ext4_dio_write_iter(iocb, from);
 	else
@@ -701,8 +724,7 @@ ext4_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
 }
 
 #ifdef CONFIG_FS_DAX
-static vm_fault_t ext4_dax_huge_fault(struct vm_fault *vmf,
-		enum page_entry_size pe_size)
+static vm_fault_t ext4_dax_huge_fault(struct vm_fault *vmf, unsigned int order)
 {
 	int error = 0;
 	vm_fault_t result;
@@ -718,14 +740,14 @@ static vm_fault_t ext4_dax_huge_fault(struct vm_fault *vmf,
 	 * read-only.
 	 *
 	 * We check for VM_SHARED rather than vmf->cow_page since the latter is
-	 * unset for pe_size != PE_SIZE_PTE (i.e. only in do_cow_fault); for
+	 * unset for order != 0 (i.e. only in do_cow_fault); for
 	 * other sizes, dax_iomap_fault will handle splitting / fallback so that
 	 * we eventually come back with a COW page.
 	 */
 	bool write = (vmf->flags & FAULT_FLAG_WRITE) &&
 		(vmf->vma->vm_flags & VM_SHARED);
 	struct address_space *mapping = vmf->vma->vm_file->f_mapping;
-	pfn_t pfn;
+	unsigned long pfn;
 
 	if (write) {
 		sb_start_pagefault(sb);
@@ -742,7 +764,7 @@ retry:
 	} else {
 		filemap_invalidate_lock_shared(mapping);
 	}
-	result = dax_iomap_fault(vmf, pe_size, &pfn, &error, &ext4_iomap_ops);
+	result = dax_iomap_fault(vmf, order, &pfn, &error, &ext4_iomap_ops);
 	if (write) {
 		ext4_journal_stop(handle);
 
@@ -751,7 +773,7 @@ retry:
 			goto retry;
 		/* Handling synchronous page fault? */
 		if (result & VM_FAULT_NEEDDSYNC)
-			result = dax_finish_sync_fault(vmf, pe_size, pfn);
+			result = dax_finish_sync_fault(vmf, order, pfn);
 		filemap_invalidate_unlock_shared(mapping);
 		sb_end_pagefault(sb);
 	} else {
@@ -763,7 +785,7 @@ retry:
 
 static vm_fault_t ext4_dax_fault(struct vm_fault *vmf)
 {
-	return ext4_dax_huge_fault(vmf, PE_SIZE_PTE);
+	return ext4_dax_huge_fault(vmf, 0);
 }
 
 static const struct vm_operations_struct ext4_dax_vm_ops = {
@@ -782,28 +804,33 @@ static const struct vm_operations_struct ext4_file_vm_ops = {
 	.page_mkwrite   = ext4_page_mkwrite,
 };
 
-static int ext4_file_mmap(struct file *file, struct vm_area_struct *vma)
+static int ext4_file_mmap_prepare(struct vm_area_desc *desc)
 {
+	int ret;
+	struct file *file = desc->file;
 	struct inode *inode = file->f_mapping->host;
-	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
-	struct dax_device *dax_dev = sbi->s_daxdev;
+	struct dax_device *dax_dev = EXT4_SB(inode->i_sb)->s_daxdev;
 
-	if (unlikely(ext4_forced_shutdown(sbi)))
-		return -EIO;
+	if (file->f_mode & FMODE_WRITE)
+		ret = ext4_emergency_state(inode->i_sb);
+	else
+		ret = ext4_forced_shutdown(inode->i_sb) ? -EIO : 0;
+	if (unlikely(ret))
+		return ret;
 
 	/*
 	 * We don't support synchronous mappings for non-DAX files and
 	 * for DAX files if underneath dax_device is not synchronous.
 	 */
-	if (!daxdev_mapping_supported(vma, dax_dev))
+	if (!daxdev_mapping_supported(desc->vm_flags, file_inode(file), dax_dev))
 		return -EOPNOTSUPP;
 
 	file_accessed(file);
 	if (IS_DAX(file_inode(file))) {
-		vma->vm_ops = &ext4_dax_vm_ops;
-		vma->vm_flags |= VM_HUGEPAGE;
+		desc->vm_ops = &ext4_dax_vm_ops;
+		desc->vm_flags |= VM_HUGEPAGE;
 	} else {
-		vma->vm_ops = &ext4_file_vm_ops;
+		desc->vm_ops = &ext4_file_vm_ops;
 	}
 	return 0;
 }
@@ -820,7 +847,8 @@ static int ext4_sample_last_mounted(struct super_block *sb,
 	if (likely(ext4_test_mount_flag(sb, EXT4_MF_MNTDIR_SAMPLED)))
 		return 0;
 
-	if (sb_rdonly(sb) || !sb_start_intwrite_trylock(sb))
+	if (ext4_emergency_state(sb) || sb_rdonly(sb) ||
+	    !sb_start_intwrite_trylock(sb))
 		return 0;
 
 	ext4_set_mount_flag(sb, EXT4_MF_MNTDIR_SAMPLED);
@@ -848,8 +876,7 @@ static int ext4_sample_last_mounted(struct super_block *sb,
 	if (err)
 		goto out_journal;
 	lock_buffer(sbi->s_sbh);
-	strncpy(sbi->s_es->s_last_mounted, cp,
-		sizeof(sbi->s_es->s_last_mounted));
+	strtomem_pad(sbi->s_es->s_last_mounted, cp, 0);
 	ext4_superblock_csum_set(sb);
 	unlock_buffer(sbi->s_sbh);
 	ext4_handle_dirty_metadata(handle, NULL, sbi->s_sbh);
@@ -864,8 +891,12 @@ static int ext4_file_open(struct inode *inode, struct file *filp)
 {
 	int ret;
 
-	if (unlikely(ext4_forced_shutdown(EXT4_SB(inode->i_sb))))
-		return -EIO;
+	if (filp->f_mode & FMODE_WRITE)
+		ret = ext4_emergency_state(inode->i_sb);
+	else
+		ret = ext4_forced_shutdown(inode->i_sb) ? -EIO : 0;
+	if (unlikely(ret))
+		return ret;
 
 	ret = ext4_sample_last_mounted(inode->i_sb, filp->f_path.mnt);
 	if (ret)
@@ -889,7 +920,10 @@ static int ext4_file_open(struct inode *inode, struct file *filp)
 			return ret;
 	}
 
-	filp->f_mode |= FMODE_NOWAIT | FMODE_BUF_RASYNC;
+	if (ext4_inode_can_atomic_write(inode))
+		filp->f_mode |= FMODE_CAN_ATOMIC_WRITE;
+
+	filp->f_mode |= FMODE_NOWAIT | FMODE_CAN_ODIRECT;
 	return dquot_file_open(inode, filp);
 }
 
@@ -901,12 +935,7 @@ static int ext4_file_open(struct inode *inode, struct file *filp)
 loff_t ext4_llseek(struct file *file, loff_t offset, int whence)
 {
 	struct inode *inode = file->f_mapping->host;
-	loff_t maxbytes;
-
-	if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
-		maxbytes = EXT4_SB(inode->i_sb)->s_bitmap_maxbytes;
-	else
-		maxbytes = inode->i_sb->s_maxbytes;
+	loff_t maxbytes = ext4_get_maxbytes(inode);
 
 	switch (whence) {
 	default:
@@ -940,15 +969,17 @@ const struct file_operations ext4_file_operations = {
 #ifdef CONFIG_COMPAT
 	.compat_ioctl	= ext4_compat_ioctl,
 #endif
-	.mmap		= ext4_file_mmap,
-	.mmap_supported_flags = MAP_SYNC,
+	.mmap_prepare	= ext4_file_mmap_prepare,
 	.open		= ext4_file_open,
 	.release	= ext4_release_file,
 	.fsync		= ext4_sync_file,
 	.get_unmapped_area = thp_get_unmapped_area,
-	.splice_read	= generic_file_splice_read,
+	.splice_read	= ext4_file_splice_read,
 	.splice_write	= iter_file_splice_write,
 	.fallocate	= ext4_fallocate,
+	.fop_flags	= FOP_MMAP_SYNC | FOP_BUFFER_RASYNC |
+			  FOP_DIO_PARALLEL_WRITE |
+			  FOP_DONTCACHE,
 };
 
 const struct inode_operations ext4_file_inode_operations = {