Merge tag 'i3c/for-7.3' of git://git.kernel.org/pub/scm/linux/kernel/git/i3c/linuxgrafted

Pull I3C updates from Alexandre Belloni:
 "A new driver this cycle, for the AMD AXI I3C controller.

  There are also new features such as IBI wakeup support, SETAASA device
  discovery and ACPI support for the the DAA methods, meaning we can now
  communicate with the SPD devices on DDR5 modules.

  New driver:
   - AMD AXI I3C master controller

  Subsystem:
   - I3C Common Command Code (CCC) handling improvements, especially
     around GET CCCs
   - SETAASA device discovery support
   - ACPI support for all existing DAA methods like SETDASA, SETNEWDA as
     well as I2C devices on I3C bus
   - IBI-based wakeup support

  Drivers:
   - dw: SETAASA support
   - mipi-i3c-hci: advertise IBI wakeup capability, AMD_PT I3C
     controller support, PIO queue management support for HCI v1.2
   - renesas: improve suspend to RAM support, add runtime PM support"

* tag 'i3c/for-7.3' of git://git.kernel.org/pub/scm/linux/kernel/git/i3c/linux: (70 commits)
  i3c: dw: reduce do_daa time if there's no client
  i3c: mipi-i3c-hci: Add support for AMD_PT I3C controller
  i3c: mipi-i3c-hci: Add PIO queue management support for HCI v1.2
  i3c: mipi-i3c-hci: Fix missing STAT_IBI_STATUS_THLD in PIO mode
  i3c: dw: rename "pclk" to "apb" to match dt-binding
  i3c: dw: make struct dw_i3c_cmd smaller
  i3c: dw: use COMMAND_PORT_TRANSFER_ARG instead of hardcoding
  i3c: renesas: Don't register devices when ENTDAA times out
  i3c: master: dw-i3c-master: fix OD timing for first broadcast
  i3c: mipi-i3c-hci: Advertise IBI wakeup capability
  i3c: mipi-i3c-hci: Factor out i3c_hci_sysdev()
  i3c: mipi-i3c-hci-pci: Propagate I3C wakeup requirements to PCI
  i3c: master: Reject IBI requests from non-IBI-capable devices
  i3c: master: Add helper to query bus wakeup requirements
  i3c: master: Report wakeup events for IBIs
  i3c: master: Support IBI-based wakeup capability
  i3c: master: Fix potential UAF in i3c_device_match()
  i3c: master: Fix potential UAF in i3c_device_uevent()
  i3c: Make dev->desc locking assumptions explicit
  i3c: master: Fix use-after-free of master->this
  ...

1 files changed, 1068 insertions, 0 deletions

diff --git a/fs/ext4/file.c b/fs/ext4/file.c
new file mode 100644
index 000000000..374b4bc25
--- /dev/null
+++ b/fs/ext4/file.c
@@ -0,0 +1,1068 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ *  linux/fs/ext4/file.c
+ *
+ * Copyright (C) 1992, 1993, 1994, 1995
+ * Remy Card (card@masi.ibp.fr)
+ * Laboratoire MASI - Institut Blaise Pascal
+ * Universite Pierre et Marie Curie (Paris VI)
+ *
+ *  from
+ *
+ *  linux/fs/minix/file.c
+ *
+ *  Copyright (C) 1991, 1992  Linus Torvalds
+ *
+ *  ext4 fs regular file handling primitives
+ *
+ *  64-bit file support on 64-bit platforms by Jakub Jelinek
+ *	(jj@sunsite.ms.mff.cuni.cz)
+ */
+
+#include <linux/time.h>
+#include <linux/fs.h>
+#include <linux/iomap.h>
+#include <linux/mount.h>
+#include <linux/path.h>
+#include <linux/dax.h>
+#include <linux/filelock.h>
+#include <linux/quotaops.h>
+#include <linux/uio.h>
+#include <linux/mman.h>
+#include <linux/backing-dev.h>
+#include "ext4.h"
+#include "ext4_jbd2.h"
+#include "xattr.h"
+#include "acl.h"
+#include "truncate.h"
+
+/*
+ * Returns %true if the given DIO request should be attempted with DIO, or
+ * %false if it should fall back to buffered I/O.
+ *
+ * DIO isn't well specified; when it's unsupported (either due to the request
+ * being misaligned, or due to the file not supporting DIO at all), filesystems
+ * either fall back to buffered I/O or return EINVAL.  For files that don't use
+ * any special features like encryption or verity, ext4 has traditionally
+ * returned EINVAL for misaligned DIO.  iomap_dio_rw() uses this convention too.
+ * In this case, we should attempt the DIO, *not* fall back to buffered I/O.
+ *
+ * In contrast, in cases where DIO is unsupported due to ext4 features, ext4
+ * traditionally falls back to buffered I/O.
+ *
+ * This function implements the traditional ext4 behavior in all these cases.
+ */
+static bool ext4_should_use_dio(struct kiocb *iocb, struct iov_iter *iter)
+{
+	struct inode *inode = file_inode(iocb->ki_filp);
+	u32 dio_align = ext4_dio_alignment(inode);
+
+	if (dio_align == 0)
+		return false;
+
+	if (dio_align == 1)
+		return true;
+
+	return IS_ALIGNED(iocb->ki_pos | iov_iter_alignment(iter), dio_align);
+}
+
+static ssize_t ext4_dio_read_iter(struct kiocb *iocb, struct iov_iter *to)
+{
+	ssize_t ret;
+	struct inode *inode = file_inode(iocb->ki_filp);
+
+	if (iocb->ki_flags & IOCB_NOWAIT) {
+		if (!inode_trylock_shared(inode))
+			return -EAGAIN;
+	} else {
+		inode_lock_shared(inode);
+	}
+
+	if (!ext4_should_use_dio(iocb, to)) {
+		inode_unlock_shared(inode);
+		/*
+		 * Fallback to buffered I/O if the operation being performed on
+		 * the inode is not supported by direct I/O. The IOCB_DIRECT
+		 * flag needs to be cleared here in order to ensure that the
+		 * direct I/O path within generic_file_read_iter() is not
+		 * taken.
+		 */
+		iocb->ki_flags &= ~IOCB_DIRECT;
+		return generic_file_read_iter(iocb, to);
+	}
+
+	ret = iomap_dio_read_simple(iocb, to, ext4_iomap_begin);
+	if (ret == -ENOTBLK)
+		ret = iomap_dio_rw(iocb, to, &ext4_iomap_ops, NULL, 0, NULL, 0);
+	inode_unlock_shared(inode);
+
+	file_accessed(iocb->ki_filp);
+	return ret;
+}
+
+#ifdef CONFIG_FS_DAX
+static ssize_t ext4_dax_read_iter(struct kiocb *iocb, struct iov_iter *to)
+{
+	struct inode *inode = file_inode(iocb->ki_filp);
+	ssize_t ret;
+
+	if (iocb->ki_flags & IOCB_NOWAIT) {
+		if (!inode_trylock_shared(inode))
+			return -EAGAIN;
+	} else {
+		inode_lock_shared(inode);
+	}
+	/*
+	 * Recheck under inode lock - at this point we are sure it cannot
+	 * change anymore
+	 */
+	if (!IS_DAX(inode)) {
+		inode_unlock_shared(inode);
+		/* Fallback to buffered IO in case we cannot support DAX */
+		return generic_file_read_iter(iocb, to);
+	}
+	ret = dax_iomap_rw(iocb, to, &ext4_iomap_ops);
+	inode_unlock_shared(inode);
+
+	file_accessed(iocb->ki_filp);
+	return ret;
+}
+#endif
+
+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(inode->i_sb)))
+		return -EIO;
+
+	if (!iov_iter_count(to))
+		return 0; /* skip atime */
+
+#ifdef CONFIG_FS_DAX
+	if (IS_DAX(inode))
+		return ext4_dax_read_iter(iocb, to);
+#endif
+	if (iocb->ki_flags & IOCB_DIRECT)
+		return ext4_dio_read_iter(iocb, 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
+ * gets called only when /all/ the files are closed.
+ */
+static int ext4_release_file(struct inode *inode, struct file *filp)
+{
+	if (ext4_test_inode_state(inode, EXT4_STATE_DA_ALLOC_CLOSE)) {
+		ext4_alloc_da_blocks(inode);
+		ext4_clear_inode_state(inode, EXT4_STATE_DA_ALLOC_CLOSE);
+	}
+	/* if we are the last writer on the inode, drop the block reservation */
+	if ((filp->f_mode & FMODE_WRITE) &&
+			(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);
+		up_write(&EXT4_I(inode)->i_data_sem);
+	}
+	if (is_dx(inode) && filp->private_data)
+		ext4_htree_free_dir_info(filp->private_data);
+
+	return 0;
+}
+
+/*
+ * This tests whether the IO in question is block-aligned or not.
+ * Ext4 utilizes unwritten extents when hole-filling during direct IO, and they
+ * are converted to written only after the IO is complete.  Until they are
+ * mapped, these blocks appear as holes, so dio_zero_block() will assume that
+ * it needs to zero out portions of the start and/or end block.  If 2 AIO
+ * threads are at work on the same unwritten block, they must be synchronized
+ * or one thread will zero the other's data, causing corruption.
+ */
+static bool
+ext4_unaligned_io(struct inode *inode, struct iov_iter *from, loff_t pos)
+{
+	struct super_block *sb = inode->i_sb;
+	unsigned long blockmask = sb->s_blocksize - 1;
+
+	if ((pos | iov_iter_alignment(from)) & blockmask)
+		return true;
+
+	return false;
+}
+
+static bool
+ext4_extending_io(struct inode *inode, loff_t offset, size_t len)
+{
+	if (offset + len > i_size_read(inode) ||
+	    offset + len > EXT4_I(inode)->i_disksize)
+		return true;
+	return false;
+}
+
+/*
+ * Does an unaligned DIO write require partial block zeroing?
+ *
+ * Partial block zeroing is performed only for the head and tail blocks
+ * when they are partially covered by the write and the underlying extent
+ * is a hole or unwritten. Middle blocks (fully covered by the write)
+ * are written as whole blocks without zeroing.
+ *
+ * When zeroing is required, two concurrent unaligned DIO writes to the
+ * same partial block can race and corrupt each other's data, so the
+ * caller must take the exclusive i_rwsem and drain in-flight DIO. When
+ * zeroing is not required, shared lock is safe -- block allocation and
+ * unwritten conversion for middle blocks are protected by i_data_sem
+ * and inode_dio_begin().
+ */
+static bool ext4_dio_needs_zeroing(struct inode *inode, loff_t pos, loff_t len)
+{
+	struct ext4_map_blocks map;
+	unsigned int blkbits = inode->i_blkbits;
+	unsigned long blockmask = inode->i_sb->s_blocksize - 1;
+	bool head_partial, tail_partial;
+	ext4_lblk_t head_lblk, tail_lblk;
+	int err;
+
+	if (pos + len > i_size_read(inode))
+		return true;
+
+	head_partial = (pos & blockmask) != 0;
+	tail_partial = ((pos + len) & blockmask) != 0;
+	head_lblk = pos >> blkbits;
+	tail_lblk = (pos + len - 1) >> blkbits;
+
+	/* Check the head partial block. */
+	if (head_partial) {
+		map.m_lblk = head_lblk;
+		map.m_len = tail_lblk - head_lblk + 1;
+		err = ext4_map_blocks(NULL, inode, &map, 0);
+		if (err <= 0 || !(map.m_flags & EXT4_MAP_MAPPED))
+			return true;
+		/* If this mapping already covers the tail block, we're done. */
+		if (!tail_partial || map.m_lblk + err > tail_lblk)
+			return false;
+	}
+
+	/* Check the tail partial block. */
+	if (tail_partial) {
+		map.m_lblk = tail_lblk;
+		map.m_len = 1;
+		err = ext4_map_blocks(NULL, inode, &map, 0);
+		if (err <= 0 || !(map.m_flags & EXT4_MAP_MAPPED))
+			return true;
+	}
+
+	return false;
+}
+
+static ssize_t ext4_generic_write_checks(struct kiocb *iocb,
+					 struct iov_iter *from)
+{
+	struct inode *inode = file_inode(iocb->ki_filp);
+	ssize_t ret;
+
+	if (unlikely(IS_IMMUTABLE(inode)))
+		return -EPERM;
+
+	ret = generic_write_checks(iocb, from);
+	if (ret <= 0)
+		return ret;
+
+	/*
+	 * If we have encountered a bitmap-format file, the size limit
+	 * is smaller than s_maxbytes, which is for extent-mapped files.
+	 */
+	if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))) {
+		struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
+
+		if (iocb->ki_pos >= sbi->s_bitmap_maxbytes)
+			return -EFBIG;
+		iov_iter_truncate(from, sbi->s_bitmap_maxbytes - iocb->ki_pos);
+	}
+
+	return iov_iter_count(from);
+}
+
+static ssize_t ext4_write_checks(struct kiocb *iocb, struct iov_iter *from)
+{
+	struct inode *inode = file_inode(iocb->ki_filp);
+	loff_t old_size = i_size_read(inode);
+	ssize_t ret, count;
+
+	count = ext4_generic_write_checks(iocb, from);
+	if (count <= 0)
+		return count;
+
+	ret = kiocb_modified(iocb);
+	if (ret)
+		return ret;
+
+	/*
+	 * If the position is beyond the EOF, it is necessary to zero out the
+	 * partial block that beyond the existing EOF, as it may contains
+	 * stale data written through mmap.
+	 */
+	if (iocb->ki_pos > old_size && !ext4_verity_in_progress(inode)) {
+		if (iocb->ki_flags & IOCB_NOWAIT)
+			return -EAGAIN;
+
+		ret = ext4_block_zero_eof(inode, old_size, iocb->ki_pos);
+		if (ret)
+			return ret;
+	}
+
+	return count;
+}
+
+static ssize_t ext4_buffered_write_iter(struct kiocb *iocb,
+					struct iov_iter *from)
+{
+	ssize_t ret;
+	struct inode *inode = file_inode(iocb->ki_filp);
+
+	if (iocb->ki_flags & IOCB_NOWAIT)
+		return -EOPNOTSUPP;
+
+	inode_lock(inode);
+
+	/*
+	 * Prevent concurrent direct I/O and buffered I/O to the same file
+	 * range. Wait for in-flight DIO to finish before dirtying pages.
+	 */
+	inode_dio_wait(inode);
+
+	ret = ext4_write_checks(iocb, from);
+	if (ret <= 0)
+		goto out;
+
+	ret = generic_perform_write(iocb, from);
+
+out:
+	inode_unlock(inode);
+	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, ssize_t count)
+{
+	handle_t *handle;
+
+	lockdep_assert_held_write(&inode->i_rwsem);
+	handle = ext4_journal_start(inode, EXT4_HT_INODE, 2);
+	if (IS_ERR(handle))
+		return PTR_ERR(handle);
+
+	if (ext4_update_inode_size(inode, offset + written)) {
+		int ret = ext4_mark_inode_dirty(handle, inode);
+		if (unlikely(ret)) {
+			ext4_journal_stop(handle);
+			return ret;
+		}
+	}
+
+	if ((written == count) && inode->i_nlink)
+		ext4_orphan_del(handle, inode);
+	ext4_journal_stop(handle);
+
+	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
+		 * still be on the orphan list. In that case, we need to try
+		 * remove the inode from the in-memory linked list.
+		 */
+		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);
+
+		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,
+				 int error, unsigned int flags)
+{
+	loff_t pos = iocb->ki_pos;
+	struct inode *inode = file_inode(iocb->ki_filp);
+
+
+	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,
+						       NULL);
+	if (error)
+		return error;
+	/*
+	 * 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.
+	 */
+	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 = {
+	.end_io = ext4_dio_write_end_io,
+};
+
+/*
+ * The intention here is to start with shared lock acquired then see if any
+ * condition requires an exclusive inode lock. If yes, then we restart the
+ * whole operation by releasing the shared lock and acquiring exclusive lock.
+ *
+ * The decision is layered, evaluated in this order:
+ *
+ * 1. If kiocb_modified() needs to update security info (!IS_NOSEC), upgrade
+ *    to the exclusive lock -- the security update itself requires it,
+ *    regardless of whether the write extends the file or is aligned.
+ *
+ * 2. If the write extends i_size or i_disksize, upgrade to the exclusive
+ *    lock to safely update i_disksize and the orphan list, regardless of
+ *    alignment.
+ *
+ * 3. Otherwise, for aligned non-extending writes, shared lock is always
+ *    sufficient regardless of extent state (written, unwritten, or hole).
+ *    truncate/punch_hole cannot run while we hold the shared i_rwsem
+ *    (they need it exclusively); after we release it, inode_dio_begin()
+ *    keeps their inode_dio_wait() blocked until in-flight bios complete.
+ *    i_data_sem serializes concurrent extent tree modifications.
+ *
+ * 4. Otherwise, the write is unaligned and non-extending. Shared lock is
+ *    safe unless the DIO layer needs to perform partial block zeroing --
+ *    i.e. the head or tail partial block sits on a hole or unwritten
+ *    extent. In that case upgrade to the exclusive lock and drain
+ *    in-flight DIO to avoid races with concurrent partial block zeroing.
+ */
+static ssize_t ext4_dio_write_checks(struct kiocb *iocb, struct iov_iter *from,
+				     bool *ilock_shared, bool *extend,
+				     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 needs_zeroing = false;
+
+restart:
+	ret = ext4_generic_write_checks(iocb, from);
+	if (ret <= 0)
+		goto out;
+
+	offset = iocb->ki_pos;
+	count = ret;
+
+	*extend = ext4_extending_io(inode, offset, count);
+
+	/*
+	 * For unaligned writes, check whether partial block zeroing will be
+	 * needed. If so, exclusive lock is required to serialize against
+	 * concurrent DIO that could race with the zeroing.
+	 *
+	 * For aligned writes we skip this check entirely since allocation
+	 * under shared lock is safe.
+	 */
+	if (ext4_unaligned_io(inode, from, offset))
+		needs_zeroing = ext4_dio_needs_zeroing(inode, offset, count);
+
+	/* Determine whether we need to upgrade to an exclusive lock. */
+	if (*ilock_shared &&
+	    (!IS_NOSEC(inode) || *extend || needs_zeroing)) {
+		if (iocb->ki_flags & IOCB_NOWAIT) {
+			ret = -EAGAIN;
+			goto out;
+		}
+		inode_unlock_shared(inode);
+		*ilock_shared = false;
+		inode_lock(inode);
+		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. When holding the exclusive lock for a write that
+	 * needs partial block zeroing or is extending the file, we must wait
+	 * for the I/O to complete synchronously:
+	 *
+	 *  - needs_zeroing: drain in-flight DIO whose end_io could race with
+	 *    our partial block zeroing, and force synchronous completion so we
+	 *    don't leave in-flight zeroing bios for the next writer to drain.
+	 *
+	 *  - extend: the caller must update i_disksize after I/O completion,
+	 *    which requires the data to be on disk first.
+	 */
+	if (!*ilock_shared && (needs_zeroing || *extend)) {
+		if (iocb->ki_flags & IOCB_NOWAIT) {
+			ret = -EAGAIN;
+			goto out;
+		}
+		if (needs_zeroing)
+			inode_dio_wait(inode);
+		*dio_flags = IOMAP_DIO_FORCE_WAIT;
+	}
+
+	ret = kiocb_modified(iocb);
+	if (ret < 0)
+		goto out;
+
+	return count;
+out:
+	if (*ilock_shared)
+		inode_unlock_shared(inode);
+	else
+		inode_unlock(inode);
+	return ret;
+}
+
+static ssize_t ext4_dio_write_iter(struct kiocb *iocb, struct iov_iter *from)
+{
+	ssize_t ret;
+	handle_t *handle;
+	struct inode *inode = file_inode(iocb->ki_filp);
+	loff_t offset = iocb->ki_pos;
+	size_t count = iov_iter_count(from);
+	bool extend = false;
+	bool ilock_shared = true;
+	int dio_flags = 0;
+
+	/*
+	 * 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.
+	 */
+	if (offset + count > i_size_read(inode))
+		ilock_shared = false;
+
+	if (iocb->ki_flags & IOCB_NOWAIT) {
+		if (ilock_shared) {
+			if (!inode_trylock_shared(inode))
+				return -EAGAIN;
+		} else {
+			if (!inode_trylock(inode))
+				return -EAGAIN;
+		}
+	} else {
+		if (ilock_shared)
+			inode_lock_shared(inode);
+		else
+			inode_lock(inode);
+	}
+
+	/* Fallback to buffered I/O if the inode does not support direct I/O. */
+	if (!ext4_should_use_dio(iocb, from)) {
+		if (ilock_shared)
+			inode_unlock_shared(inode);
+		else
+			inode_unlock(inode);
+		return ext4_buffered_write_iter(iocb, from);
+	}
+
+	/*
+	 * 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,
+				    &dio_flags);
+	if (ret <= 0)
+		return ret;
+
+	offset = iocb->ki_pos;
+	count = ret;
+
+	if (extend) {
+		handle = ext4_journal_start(inode, EXT4_HT_INODE, 2);
+		if (IS_ERR(handle)) {
+			ret = PTR_ERR(handle);
+			goto out;
+		}
+
+		ret = ext4_orphan_add(handle, inode);
+		ext4_journal_stop(handle);
+		if (ret)
+			goto out;
+	}
+
+	ret = iomap_dio_rw(iocb, from, &ext4_iomap_ops, &ext4_dio_write_ops,
+			   dio_flags, NULL, 0);
+	if (ret == -ENOTBLK)
+		ret = 0;
+	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)
+		inode_unlock_shared(inode);
+	else
+		inode_unlock(inode);
+
+	if (ret >= 0 && iov_iter_count(from)) {
+		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)
+			return err;
+
+		/*
+		 * We need to ensure that the pages within the page cache for
+		 * the range covered by this I/O are written to disk and
+		 * invalidated. This is in attempt to preserve the expected
+		 * direct I/O semantics in the case we fallback to buffered I/O
+		 * to complete off the I/O request.
+		 */
+		ret += err;
+		endbyte = offset + err - 1;
+		err = filemap_write_and_wait_range(iocb->ki_filp->f_mapping,
+						   offset, endbyte);
+		if (!err)
+			invalidate_mapping_pages(iocb->ki_filp->f_mapping,
+						 offset >> PAGE_SHIFT,
+						 endbyte >> PAGE_SHIFT);
+	}
+
+	return ret;
+}
+
+#ifdef CONFIG_FS_DAX
+static ssize_t
+ext4_dax_write_iter(struct kiocb *iocb, struct iov_iter *from)
+{
+	ssize_t ret;
+	size_t count;
+	loff_t offset;
+	handle_t *handle;
+	bool extend = false;
+	struct inode *inode = file_inode(iocb->ki_filp);
+
+	if (iocb->ki_flags & IOCB_NOWAIT) {
+		if (!inode_trylock(inode))
+			return -EAGAIN;
+	} else {
+		inode_lock(inode);
+	}
+
+	ret = ext4_write_checks(iocb, from);
+	if (ret <= 0)
+		goto out;
+
+	offset = iocb->ki_pos;
+	count = iov_iter_count(from);
+
+	if (offset + count > EXT4_I(inode)->i_disksize) {
+		if (iocb->ki_flags & IOCB_NOWAIT) {
+			ret = -EAGAIN;
+			goto out;
+		}
+
+		handle = ext4_journal_start(inode, EXT4_HT_INODE, 2);
+		if (IS_ERR(handle)) {
+			ret = PTR_ERR(handle);
+			goto out;
+		}
+
+		ret = ext4_orphan_add(handle, inode);
+		if (ret) {
+			ext4_journal_stop(handle);
+			goto out;
+		}
+
+		extend = true;
+		ext4_journal_stop(handle);
+	}
+
+	ret = dax_iomap_rw(iocb, from, &ext4_iomap_ops);
+
+	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)
+		ret = generic_write_sync(iocb, ret);
+	return ret;
+}
+#endif
+
+static ssize_t
+ext4_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
+{
+	int ret;
+	struct inode *inode = file_inode(iocb->ki_filp);
+
+	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
+		return ext4_buffered_write_iter(iocb, from);
+}
+
+#ifdef CONFIG_FS_DAX
+static vm_fault_t ext4_dax_huge_fault(struct vm_fault *vmf, unsigned int order)
+{
+	int error = 0;
+	vm_fault_t result;
+	int retries = 0;
+	handle_t *handle = NULL;
+	struct inode *inode = file_inode(vmf->vma->vm_file);
+	struct super_block *sb = inode->i_sb;
+
+	/*
+	 * We have to distinguish real writes from writes which will result in a
+	 * COW page; COW writes should *not* poke the journal (the file will not
+	 * be changed). Doing so would cause unintended failures when mounted
+	 * read-only.
+	 *
+	 * We check for VM_SHARED rather than vmf->cow_page since the latter is
+	 * 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;
+	unsigned long pfn;
+
+	if (write) {
+		sb_start_pagefault(sb);
+		file_update_time(vmf->vma->vm_file);
+		filemap_invalidate_lock_shared(mapping);
+retry:
+		handle = ext4_journal_start_sb(sb, EXT4_HT_WRITE_PAGE,
+					       EXT4_DATA_TRANS_BLOCKS(sb));
+		if (IS_ERR(handle)) {
+			filemap_invalidate_unlock_shared(mapping);
+			sb_end_pagefault(sb);
+			return VM_FAULT_SIGBUS;
+		}
+	} else {
+		filemap_invalidate_lock_shared(mapping);
+	}
+	result = dax_iomap_fault(vmf, order, &pfn, &error, &ext4_iomap_ops);
+	if (write) {
+		ext4_journal_stop(handle);
+
+		if ((result & VM_FAULT_ERROR) && error == -ENOSPC &&
+		    ext4_should_retry_alloc(sb, &retries))
+			goto retry;
+		/* Handling synchronous page fault? */
+		if (result & VM_FAULT_NEEDDSYNC)
+			result = dax_finish_sync_fault(vmf, order, pfn);
+		filemap_invalidate_unlock_shared(mapping);
+		sb_end_pagefault(sb);
+	} else {
+		filemap_invalidate_unlock_shared(mapping);
+	}
+
+	return result;
+}
+
+static vm_fault_t ext4_dax_fault(struct vm_fault *vmf)
+{
+	return ext4_dax_huge_fault(vmf, 0);
+}
+
+static const struct vm_operations_struct ext4_dax_vm_ops = {
+	.fault		= ext4_dax_fault,
+	.huge_fault	= ext4_dax_huge_fault,
+	.page_mkwrite	= ext4_dax_fault,
+	.pfn_mkwrite	= ext4_dax_fault,
+};
+#else
+#define ext4_dax_vm_ops	ext4_file_vm_ops
+#endif
+
+static const struct vm_operations_struct ext4_file_vm_ops = {
+	.fault		= filemap_fault,
+	.map_pages	= filemap_map_pages,
+	.page_mkwrite   = ext4_page_mkwrite,
+};
+
+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 dax_device *dax_dev = EXT4_SB(inode->i_sb)->s_daxdev;
+
+	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(desc, file_inode(file), dax_dev))
+		return -EOPNOTSUPP;
+
+	file_accessed(file);
+	if (IS_DAX(file_inode(file))) {
+		desc->vm_ops = &ext4_dax_vm_ops;
+		vma_desc_set_flags(desc, VMA_HUGEPAGE_BIT);
+	} else {
+		desc->vm_ops = &ext4_file_vm_ops;
+	}
+	return 0;
+}
+
+static int ext4_sample_last_mounted(struct super_block *sb,
+				    struct vfsmount *mnt)
+{
+	struct ext4_sb_info *sbi = EXT4_SB(sb);
+	struct path path;
+	char buf[64], *cp;
+	handle_t *handle;
+	int err;
+
+	if (likely(ext4_test_mount_flag(sb, EXT4_MF_MNTDIR_SAMPLED)))
+		return 0;
+
+	if (ext4_emergency_state(sb) || sb_rdonly(sb) ||
+	    !sb_start_intwrite_trylock(sb))
+		return 0;
+
+	ext4_set_mount_flag(sb, EXT4_MF_MNTDIR_SAMPLED);
+	/*
+	 * Sample where the filesystem has been mounted and
+	 * store it in the superblock for sysadmin convenience
+	 * when trying to sort through large numbers of block
+	 * devices or filesystem images.
+	 */
+	path.mnt = mnt;
+	path.dentry = mnt->mnt_root;
+	cp = d_path(&path, buf, sizeof(buf));
+	err = 0;
+	if (IS_ERR(cp))
+		goto out;
+
+	handle = ext4_journal_start_sb(sb, EXT4_HT_MISC, 1);
+	err = PTR_ERR(handle);
+	if (IS_ERR(handle))
+		goto out;
+	BUFFER_TRACE(sbi->s_sbh, "get_write_access");
+	err = ext4_journal_get_write_access(handle, sb, sbi->s_sbh,
+					    EXT4_JTR_NONE);
+	if (err)
+		goto out_journal;
+	lock_buffer(sbi->s_sbh);
+	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);
+out_journal:
+	ext4_journal_stop(handle);
+out:
+	sb_end_intwrite(sb);
+	return err;
+}
+
+static int ext4_file_open(struct inode *inode, struct file *filp)
+{
+	int ret;
+
+	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)
+		return ret;
+
+	ret = fscrypt_file_open(inode, filp);
+	if (ret)
+		return ret;
+
+	ret = fsverity_file_open(inode, filp);
+	if (ret)
+		return ret;
+
+	/*
+	 * Set up the jbd2_inode if we are opening the inode for
+	 * writing and the journal is present
+	 */
+	if (filp->f_mode & FMODE_WRITE) {
+		ret = ext4_inode_attach_jinode(inode);
+		if (ret < 0)
+			return ret;
+	}
+
+	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);
+}
+
+/*
+ * ext4_llseek() handles both block-mapped and extent-mapped maxbytes values
+ * by calling generic_file_llseek_size() with the appropriate maxbytes
+ * value for each.
+ */
+loff_t ext4_llseek(struct file *file, loff_t offset, int whence)
+{
+	struct inode *inode = file->f_mapping->host;
+	loff_t maxbytes = ext4_get_maxbytes(inode);
+
+	switch (whence) {
+	default:
+		return generic_file_llseek_size(file, offset, whence,
+						maxbytes, i_size_read(inode));
+	case SEEK_HOLE:
+		inode_lock_shared(inode);
+		offset = iomap_seek_hole(inode, offset,
+					 &ext4_iomap_report_ops);
+		inode_unlock_shared(inode);
+		break;
+	case SEEK_DATA:
+		inode_lock_shared(inode);
+		offset = iomap_seek_data(inode, offset,
+					 &ext4_iomap_report_ops);
+		inode_unlock_shared(inode);
+		break;
+	}
+
+	if (offset < 0)
+		return offset;
+	return vfs_setpos(file, offset, maxbytes);
+}
+
+const struct file_operations ext4_file_operations = {
+	.llseek		= ext4_llseek,
+	.read_iter	= ext4_file_read_iter,
+	.write_iter	= ext4_file_write_iter,
+	.iopoll		= iocb_bio_iopoll,
+	.unlocked_ioctl = ext4_ioctl,
+#ifdef CONFIG_COMPAT
+	.compat_ioctl	= ext4_compat_ioctl,
+#endif
+	.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	= 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,
+	.setlease	= generic_setlease,
+};
+
+const struct inode_operations ext4_file_inode_operations = {
+	.setattr	= ext4_setattr,
+	.getattr	= ext4_file_getattr,
+	.listxattr	= ext4_listxattr,
+	.get_inode_acl	= ext4_get_acl,
+	.set_acl	= ext4_set_acl,
+	.fiemap		= ext4_fiemap,
+	.fileattr_get	= ext4_fileattr_get,
+	.fileattr_set	= ext4_fileattr_set,
+};
+