Adding upstream version 6.1.76.upstream/6.1.76

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 3540 insertions, 0 deletions

diff --git a/fs/xfs/xfs_inode.c b/fs/xfs/xfs_inode.c
new file mode 100644
index 000000000..aa303be11
--- /dev/null
+++ b/fs/xfs/xfs_inode.c
@@ -0,0 +1,3540 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2000-2006 Silicon Graphics, Inc.
+ * All Rights Reserved.
+ */
+#include <linux/iversion.h>
+
+#include "xfs.h"
+#include "xfs_fs.h"
+#include "xfs_shared.h"
+#include "xfs_format.h"
+#include "xfs_log_format.h"
+#include "xfs_trans_resv.h"
+#include "xfs_mount.h"
+#include "xfs_defer.h"
+#include "xfs_inode.h"
+#include "xfs_dir2.h"
+#include "xfs_attr.h"
+#include "xfs_trans_space.h"
+#include "xfs_trans.h"
+#include "xfs_buf_item.h"
+#include "xfs_inode_item.h"
+#include "xfs_iunlink_item.h"
+#include "xfs_ialloc.h"
+#include "xfs_bmap.h"
+#include "xfs_bmap_util.h"
+#include "xfs_errortag.h"
+#include "xfs_error.h"
+#include "xfs_quota.h"
+#include "xfs_filestream.h"
+#include "xfs_trace.h"
+#include "xfs_icache.h"
+#include "xfs_symlink.h"
+#include "xfs_trans_priv.h"
+#include "xfs_log.h"
+#include "xfs_bmap_btree.h"
+#include "xfs_reflink.h"
+#include "xfs_ag.h"
+#include "xfs_log_priv.h"
+
+struct kmem_cache *xfs_inode_cache;
+
+/*
+ * Used in xfs_itruncate_extents().  This is the maximum number of extents
+ * freed from a file in a single transaction.
+ */
+#define	XFS_ITRUNC_MAX_EXTENTS	2
+
+STATIC int xfs_iunlink(struct xfs_trans *, struct xfs_inode *);
+STATIC int xfs_iunlink_remove(struct xfs_trans *tp, struct xfs_perag *pag,
+	struct xfs_inode *);
+
+/*
+ * helper function to extract extent size hint from inode
+ */
+xfs_extlen_t
+xfs_get_extsz_hint(
+	struct xfs_inode	*ip)
+{
+	/*
+	 * No point in aligning allocations if we need to COW to actually
+	 * write to them.
+	 */
+	if (xfs_is_always_cow_inode(ip))
+		return 0;
+	if ((ip->i_diflags & XFS_DIFLAG_EXTSIZE) && ip->i_extsize)
+		return ip->i_extsize;
+	if (XFS_IS_REALTIME_INODE(ip))
+		return ip->i_mount->m_sb.sb_rextsize;
+	return 0;
+}
+
+/*
+ * Helper function to extract CoW extent size hint from inode.
+ * Between the extent size hint and the CoW extent size hint, we
+ * return the greater of the two.  If the value is zero (automatic),
+ * use the default size.
+ */
+xfs_extlen_t
+xfs_get_cowextsz_hint(
+	struct xfs_inode	*ip)
+{
+	xfs_extlen_t		a, b;
+
+	a = 0;
+	if (ip->i_diflags2 & XFS_DIFLAG2_COWEXTSIZE)
+		a = ip->i_cowextsize;
+	b = xfs_get_extsz_hint(ip);
+
+	a = max(a, b);
+	if (a == 0)
+		return XFS_DEFAULT_COWEXTSZ_HINT;
+	return a;
+}
+
+/*
+ * These two are wrapper routines around the xfs_ilock() routine used to
+ * centralize some grungy code.  They are used in places that wish to lock the
+ * inode solely for reading the extents.  The reason these places can't just
+ * call xfs_ilock(ip, XFS_ILOCK_SHARED) is that the inode lock also guards to
+ * bringing in of the extents from disk for a file in b-tree format.  If the
+ * inode is in b-tree format, then we need to lock the inode exclusively until
+ * the extents are read in.  Locking it exclusively all the time would limit
+ * our parallelism unnecessarily, though.  What we do instead is check to see
+ * if the extents have been read in yet, and only lock the inode exclusively
+ * if they have not.
+ *
+ * The functions return a value which should be given to the corresponding
+ * xfs_iunlock() call.
+ */
+uint
+xfs_ilock_data_map_shared(
+	struct xfs_inode	*ip)
+{
+	uint			lock_mode = XFS_ILOCK_SHARED;
+
+	if (xfs_need_iread_extents(&ip->i_df))
+		lock_mode = XFS_ILOCK_EXCL;
+	xfs_ilock(ip, lock_mode);
+	return lock_mode;
+}
+
+uint
+xfs_ilock_attr_map_shared(
+	struct xfs_inode	*ip)
+{
+	uint			lock_mode = XFS_ILOCK_SHARED;
+
+	if (xfs_inode_has_attr_fork(ip) && xfs_need_iread_extents(&ip->i_af))
+		lock_mode = XFS_ILOCK_EXCL;
+	xfs_ilock(ip, lock_mode);
+	return lock_mode;
+}
+
+/*
+ * You can't set both SHARED and EXCL for the same lock,
+ * and only XFS_IOLOCK_SHARED, XFS_IOLOCK_EXCL, XFS_MMAPLOCK_SHARED,
+ * XFS_MMAPLOCK_EXCL, XFS_ILOCK_SHARED, XFS_ILOCK_EXCL are valid values
+ * to set in lock_flags.
+ */
+static inline void
+xfs_lock_flags_assert(
+	uint		lock_flags)
+{
+	ASSERT((lock_flags & (XFS_IOLOCK_SHARED | XFS_IOLOCK_EXCL)) !=
+		(XFS_IOLOCK_SHARED | XFS_IOLOCK_EXCL));
+	ASSERT((lock_flags & (XFS_MMAPLOCK_SHARED | XFS_MMAPLOCK_EXCL)) !=
+		(XFS_MMAPLOCK_SHARED | XFS_MMAPLOCK_EXCL));
+	ASSERT((lock_flags & (XFS_ILOCK_SHARED | XFS_ILOCK_EXCL)) !=
+		(XFS_ILOCK_SHARED | XFS_ILOCK_EXCL));
+	ASSERT((lock_flags & ~(XFS_LOCK_MASK | XFS_LOCK_SUBCLASS_MASK)) == 0);
+	ASSERT(lock_flags != 0);
+}
+
+/*
+ * In addition to i_rwsem in the VFS inode, the xfs inode contains 2
+ * multi-reader locks: invalidate_lock and the i_lock.  This routine allows
+ * various combinations of the locks to be obtained.
+ *
+ * The 3 locks should always be ordered so that the IO lock is obtained first,
+ * the mmap lock second and the ilock last in order to prevent deadlock.
+ *
+ * Basic locking order:
+ *
+ * i_rwsem -> invalidate_lock -> page_lock -> i_ilock
+ *
+ * mmap_lock locking order:
+ *
+ * i_rwsem -> page lock -> mmap_lock
+ * mmap_lock -> invalidate_lock -> page_lock
+ *
+ * The difference in mmap_lock locking order mean that we cannot hold the
+ * invalidate_lock over syscall based read(2)/write(2) based IO. These IO paths
+ * can fault in pages during copy in/out (for buffered IO) or require the
+ * mmap_lock in get_user_pages() to map the user pages into the kernel address
+ * space for direct IO. Similarly the i_rwsem cannot be taken inside a page
+ * fault because page faults already hold the mmap_lock.
+ *
+ * Hence to serialise fully against both syscall and mmap based IO, we need to
+ * take both the i_rwsem and the invalidate_lock. These locks should *only* be
+ * both taken in places where we need to invalidate the page cache in a race
+ * free manner (e.g. truncate, hole punch and other extent manipulation
+ * functions).
+ */
+void
+xfs_ilock(
+	xfs_inode_t		*ip,
+	uint			lock_flags)
+{
+	trace_xfs_ilock(ip, lock_flags, _RET_IP_);
+
+	xfs_lock_flags_assert(lock_flags);
+
+	if (lock_flags & XFS_IOLOCK_EXCL) {
+		down_write_nested(&VFS_I(ip)->i_rwsem,
+				  XFS_IOLOCK_DEP(lock_flags));
+	} else if (lock_flags & XFS_IOLOCK_SHARED) {
+		down_read_nested(&VFS_I(ip)->i_rwsem,
+				 XFS_IOLOCK_DEP(lock_flags));
+	}
+
+	if (lock_flags & XFS_MMAPLOCK_EXCL) {
+		down_write_nested(&VFS_I(ip)->i_mapping->invalidate_lock,
+				  XFS_MMAPLOCK_DEP(lock_flags));
+	} else if (lock_flags & XFS_MMAPLOCK_SHARED) {
+		down_read_nested(&VFS_I(ip)->i_mapping->invalidate_lock,
+				 XFS_MMAPLOCK_DEP(lock_flags));
+	}
+
+	if (lock_flags & XFS_ILOCK_EXCL)
+		mrupdate_nested(&ip->i_lock, XFS_ILOCK_DEP(lock_flags));
+	else if (lock_flags & XFS_ILOCK_SHARED)
+		mraccess_nested(&ip->i_lock, XFS_ILOCK_DEP(lock_flags));
+}
+
+/*
+ * This is just like xfs_ilock(), except that the caller
+ * is guaranteed not to sleep.  It returns 1 if it gets
+ * the requested locks and 0 otherwise.  If the IO lock is
+ * obtained but the inode lock cannot be, then the IO lock
+ * is dropped before returning.
+ *
+ * ip -- the inode being locked
+ * lock_flags -- this parameter indicates the inode's locks to be
+ *       to be locked.  See the comment for xfs_ilock() for a list
+ *	 of valid values.
+ */
+int
+xfs_ilock_nowait(
+	xfs_inode_t		*ip,
+	uint			lock_flags)
+{
+	trace_xfs_ilock_nowait(ip, lock_flags, _RET_IP_);
+
+	xfs_lock_flags_assert(lock_flags);
+
+	if (lock_flags & XFS_IOLOCK_EXCL) {
+		if (!down_write_trylock(&VFS_I(ip)->i_rwsem))
+			goto out;
+	} else if (lock_flags & XFS_IOLOCK_SHARED) {
+		if (!down_read_trylock(&VFS_I(ip)->i_rwsem))
+			goto out;
+	}
+
+	if (lock_flags & XFS_MMAPLOCK_EXCL) {
+		if (!down_write_trylock(&VFS_I(ip)->i_mapping->invalidate_lock))
+			goto out_undo_iolock;
+	} else if (lock_flags & XFS_MMAPLOCK_SHARED) {
+		if (!down_read_trylock(&VFS_I(ip)->i_mapping->invalidate_lock))
+			goto out_undo_iolock;
+	}
+
+	if (lock_flags & XFS_ILOCK_EXCL) {
+		if (!mrtryupdate(&ip->i_lock))
+			goto out_undo_mmaplock;
+	} else if (lock_flags & XFS_ILOCK_SHARED) {
+		if (!mrtryaccess(&ip->i_lock))
+			goto out_undo_mmaplock;
+	}
+	return 1;
+
+out_undo_mmaplock:
+	if (lock_flags & XFS_MMAPLOCK_EXCL)
+		up_write(&VFS_I(ip)->i_mapping->invalidate_lock);
+	else if (lock_flags & XFS_MMAPLOCK_SHARED)
+		up_read(&VFS_I(ip)->i_mapping->invalidate_lock);
+out_undo_iolock:
+	if (lock_flags & XFS_IOLOCK_EXCL)
+		up_write(&VFS_I(ip)->i_rwsem);
+	else if (lock_flags & XFS_IOLOCK_SHARED)
+		up_read(&VFS_I(ip)->i_rwsem);
+out:
+	return 0;
+}
+
+/*
+ * xfs_iunlock() is used to drop the inode locks acquired with
+ * xfs_ilock() and xfs_ilock_nowait().  The caller must pass
+ * in the flags given to xfs_ilock() or xfs_ilock_nowait() so
+ * that we know which locks to drop.
+ *
+ * ip -- the inode being unlocked
+ * lock_flags -- this parameter indicates the inode's locks to be
+ *       to be unlocked.  See the comment for xfs_ilock() for a list
+ *	 of valid values for this parameter.
+ *
+ */
+void
+xfs_iunlock(
+	xfs_inode_t		*ip,
+	uint			lock_flags)
+{
+	xfs_lock_flags_assert(lock_flags);
+
+	if (lock_flags & XFS_IOLOCK_EXCL)
+		up_write(&VFS_I(ip)->i_rwsem);
+	else if (lock_flags & XFS_IOLOCK_SHARED)
+		up_read(&VFS_I(ip)->i_rwsem);
+
+	if (lock_flags & XFS_MMAPLOCK_EXCL)
+		up_write(&VFS_I(ip)->i_mapping->invalidate_lock);
+	else if (lock_flags & XFS_MMAPLOCK_SHARED)
+		up_read(&VFS_I(ip)->i_mapping->invalidate_lock);
+
+	if (lock_flags & XFS_ILOCK_EXCL)
+		mrunlock_excl(&ip->i_lock);
+	else if (lock_flags & XFS_ILOCK_SHARED)
+		mrunlock_shared(&ip->i_lock);
+
+	trace_xfs_iunlock(ip, lock_flags, _RET_IP_);
+}
+
+/*
+ * give up write locks.  the i/o lock cannot be held nested
+ * if it is being demoted.
+ */
+void
+xfs_ilock_demote(
+	xfs_inode_t		*ip,
+	uint			lock_flags)
+{
+	ASSERT(lock_flags & (XFS_IOLOCK_EXCL|XFS_MMAPLOCK_EXCL|XFS_ILOCK_EXCL));
+	ASSERT((lock_flags &
+		~(XFS_IOLOCK_EXCL|XFS_MMAPLOCK_EXCL|XFS_ILOCK_EXCL)) == 0);
+
+	if (lock_flags & XFS_ILOCK_EXCL)
+		mrdemote(&ip->i_lock);
+	if (lock_flags & XFS_MMAPLOCK_EXCL)
+		downgrade_write(&VFS_I(ip)->i_mapping->invalidate_lock);
+	if (lock_flags & XFS_IOLOCK_EXCL)
+		downgrade_write(&VFS_I(ip)->i_rwsem);
+
+	trace_xfs_ilock_demote(ip, lock_flags, _RET_IP_);
+}
+
+#if defined(DEBUG) || defined(XFS_WARN)
+static inline bool
+__xfs_rwsem_islocked(
+	struct rw_semaphore	*rwsem,
+	bool			shared)
+{
+	if (!debug_locks)
+		return rwsem_is_locked(rwsem);
+
+	if (!shared)
+		return lockdep_is_held_type(rwsem, 0);
+
+	/*
+	 * We are checking that the lock is held at least in shared
+	 * mode but don't care that it might be held exclusively
+	 * (i.e. shared | excl). Hence we check if the lock is held
+	 * in any mode rather than an explicit shared mode.
+	 */
+	return lockdep_is_held_type(rwsem, -1);
+}
+
+bool
+xfs_isilocked(
+	struct xfs_inode	*ip,
+	uint			lock_flags)
+{
+	if (lock_flags & (XFS_ILOCK_EXCL|XFS_ILOCK_SHARED)) {
+		if (!(lock_flags & XFS_ILOCK_SHARED))
+			return !!ip->i_lock.mr_writer;
+		return rwsem_is_locked(&ip->i_lock.mr_lock);
+	}
+
+	if (lock_flags & (XFS_MMAPLOCK_EXCL|XFS_MMAPLOCK_SHARED)) {
+		return __xfs_rwsem_islocked(&VFS_I(ip)->i_mapping->invalidate_lock,
+				(lock_flags & XFS_MMAPLOCK_SHARED));
+	}
+
+	if (lock_flags & (XFS_IOLOCK_EXCL | XFS_IOLOCK_SHARED)) {
+		return __xfs_rwsem_islocked(&VFS_I(ip)->i_rwsem,
+				(lock_flags & XFS_IOLOCK_SHARED));
+	}
+
+	ASSERT(0);
+	return false;
+}
+#endif
+
+/*
+ * xfs_lockdep_subclass_ok() is only used in an ASSERT, so is only called when
+ * DEBUG or XFS_WARN is set. And MAX_LOCKDEP_SUBCLASSES is then only defined
+ * when CONFIG_LOCKDEP is set. Hence the complex define below to avoid build
+ * errors and warnings.
+ */
+#if (defined(DEBUG) || defined(XFS_WARN)) && defined(CONFIG_LOCKDEP)
+static bool
+xfs_lockdep_subclass_ok(
+	int subclass)
+{
+	return subclass < MAX_LOCKDEP_SUBCLASSES;
+}
+#else
+#define xfs_lockdep_subclass_ok(subclass)	(true)
+#endif
+
+/*
+ * Bump the subclass so xfs_lock_inodes() acquires each lock with a different
+ * value. This can be called for any type of inode lock combination, including
+ * parent locking. Care must be taken to ensure we don't overrun the subclass
+ * storage fields in the class mask we build.
+ */
+static inline uint
+xfs_lock_inumorder(
+	uint	lock_mode,
+	uint	subclass)
+{
+	uint	class = 0;
+
+	ASSERT(!(lock_mode & (XFS_ILOCK_PARENT | XFS_ILOCK_RTBITMAP |
+			      XFS_ILOCK_RTSUM)));
+	ASSERT(xfs_lockdep_subclass_ok(subclass));
+
+	if (lock_mode & (XFS_IOLOCK_SHARED|XFS_IOLOCK_EXCL)) {
+		ASSERT(subclass <= XFS_IOLOCK_MAX_SUBCLASS);
+		class += subclass << XFS_IOLOCK_SHIFT;
+	}
+
+	if (lock_mode & (XFS_MMAPLOCK_SHARED|XFS_MMAPLOCK_EXCL)) {
+		ASSERT(subclass <= XFS_MMAPLOCK_MAX_SUBCLASS);
+		class += subclass << XFS_MMAPLOCK_SHIFT;
+	}
+
+	if (lock_mode & (XFS_ILOCK_SHARED|XFS_ILOCK_EXCL)) {
+		ASSERT(subclass <= XFS_ILOCK_MAX_SUBCLASS);
+		class += subclass << XFS_ILOCK_SHIFT;
+	}
+
+	return (lock_mode & ~XFS_LOCK_SUBCLASS_MASK) | class;
+}
+
+/*
+ * The following routine will lock n inodes in exclusive mode.  We assume the
+ * caller calls us with the inodes in i_ino order.
+ *
+ * We need to detect deadlock where an inode that we lock is in the AIL and we
+ * start waiting for another inode that is locked by a thread in a long running
+ * transaction (such as truncate). This can result in deadlock since the long
+ * running trans might need to wait for the inode we just locked in order to
+ * push the tail and free space in the log.
+ *
+ * xfs_lock_inodes() can only be used to lock one type of lock at a time -
+ * the iolock, the mmaplock or the ilock, but not more than one at a time. If we
+ * lock more than one at a time, lockdep will report false positives saying we
+ * have violated locking orders.
+ */
+static void
+xfs_lock_inodes(
+	struct xfs_inode	**ips,
+	int			inodes,
+	uint			lock_mode)
+{
+	int			attempts = 0;
+	uint			i;
+	int			j;
+	bool			try_lock;
+	struct xfs_log_item	*lp;
+
+	/*
+	 * Currently supports between 2 and 5 inodes with exclusive locking.  We
+	 * support an arbitrary depth of locking here, but absolute limits on
+	 * inodes depend on the type of locking and the limits placed by
+	 * lockdep annotations in xfs_lock_inumorder.  These are all checked by
+	 * the asserts.
+	 */
+	ASSERT(ips && inodes >= 2 && inodes <= 5);
+	ASSERT(lock_mode & (XFS_IOLOCK_EXCL | XFS_MMAPLOCK_EXCL |
+			    XFS_ILOCK_EXCL));
+	ASSERT(!(lock_mode & (XFS_IOLOCK_SHARED | XFS_MMAPLOCK_SHARED |
+			      XFS_ILOCK_SHARED)));
+	ASSERT(!(lock_mode & XFS_MMAPLOCK_EXCL) ||
+		inodes <= XFS_MMAPLOCK_MAX_SUBCLASS + 1);
+	ASSERT(!(lock_mode & XFS_ILOCK_EXCL) ||
+		inodes <= XFS_ILOCK_MAX_SUBCLASS + 1);
+
+	if (lock_mode & XFS_IOLOCK_EXCL) {
+		ASSERT(!(lock_mode & (XFS_MMAPLOCK_EXCL | XFS_ILOCK_EXCL)));
+	} else if (lock_mode & XFS_MMAPLOCK_EXCL)
+		ASSERT(!(lock_mode & XFS_ILOCK_EXCL));
+
+again:
+	try_lock = false;
+	i = 0;
+	for (; i < inodes; i++) {
+		ASSERT(ips[i]);
+
+		if (i && (ips[i] == ips[i - 1]))	/* Already locked */
+			continue;
+
+		/*
+		 * If try_lock is not set yet, make sure all locked inodes are
+		 * not in the AIL.  If any are, set try_lock to be used later.
+		 */
+		if (!try_lock) {
+			for (j = (i - 1); j >= 0 && !try_lock; j--) {
+				lp = &ips[j]->i_itemp->ili_item;
+				if (lp && test_bit(XFS_LI_IN_AIL, &lp->li_flags))
+					try_lock = true;
+			}
+		}
+
+		/*
+		 * If any of the previous locks we have locked is in the AIL,
+		 * we must TRY to get the second and subsequent locks. If
+		 * we can't get any, we must release all we have
+		 * and try again.
+		 */
+		if (!try_lock) {
+			xfs_ilock(ips[i], xfs_lock_inumorder(lock_mode, i));
+			continue;
+		}
+
+		/* try_lock means we have an inode locked that is in the AIL. */
+		ASSERT(i != 0);
+		if (xfs_ilock_nowait(ips[i], xfs_lock_inumorder(lock_mode, i)))
+			continue;
+
+		/*
+		 * Unlock all previous guys and try again.  xfs_iunlock will try
+		 * to push the tail if the inode is in the AIL.
+		 */
+		attempts++;
+		for (j = i - 1; j >= 0; j--) {
+			/*
+			 * Check to see if we've already unlocked this one.  Not
+			 * the first one going back, and the inode ptr is the
+			 * same.
+			 */
+			if (j != (i - 1) && ips[j] == ips[j + 1])
+				continue;
+
+			xfs_iunlock(ips[j], lock_mode);
+		}
+
+		if ((attempts % 5) == 0) {
+			delay(1); /* Don't just spin the CPU */
+		}
+		goto again;
+	}
+}
+
+/*
+ * xfs_lock_two_inodes() can only be used to lock ilock. The iolock and
+ * mmaplock must be double-locked separately since we use i_rwsem and
+ * invalidate_lock for that. We now support taking one lock EXCL and the
+ * other SHARED.
+ */
+void
+xfs_lock_two_inodes(
+	struct xfs_inode	*ip0,
+	uint			ip0_mode,
+	struct xfs_inode	*ip1,
+	uint			ip1_mode)
+{
+	int			attempts = 0;
+	struct xfs_log_item	*lp;
+
+	ASSERT(hweight32(ip0_mode) == 1);
+	ASSERT(hweight32(ip1_mode) == 1);
+	ASSERT(!(ip0_mode & (XFS_IOLOCK_SHARED|XFS_IOLOCK_EXCL)));
+	ASSERT(!(ip1_mode & (XFS_IOLOCK_SHARED|XFS_IOLOCK_EXCL)));
+	ASSERT(!(ip0_mode & (XFS_MMAPLOCK_SHARED|XFS_MMAPLOCK_EXCL)));
+	ASSERT(!(ip1_mode & (XFS_MMAPLOCK_SHARED|XFS_MMAPLOCK_EXCL)));
+	ASSERT(ip0->i_ino != ip1->i_ino);
+
+	if (ip0->i_ino > ip1->i_ino) {
+		swap(ip0, ip1);
+		swap(ip0_mode, ip1_mode);
+	}
+
+ again:
+	xfs_ilock(ip0, xfs_lock_inumorder(ip0_mode, 0));
+
+	/*
+	 * If the first lock we have locked is in the AIL, we must TRY to get
+	 * the second lock. If we can't get it, we must release the first one
+	 * and try again.
+	 */
+	lp = &ip0->i_itemp->ili_item;
+	if (lp && test_bit(XFS_LI_IN_AIL, &lp->li_flags)) {
+		if (!xfs_ilock_nowait(ip1, xfs_lock_inumorder(ip1_mode, 1))) {
+			xfs_iunlock(ip0, ip0_mode);
+			if ((++attempts % 5) == 0)
+				delay(1); /* Don't just spin the CPU */
+			goto again;
+		}
+	} else {
+		xfs_ilock(ip1, xfs_lock_inumorder(ip1_mode, 1));
+	}
+}
+
+uint
+xfs_ip2xflags(
+	struct xfs_inode	*ip)
+{
+	uint			flags = 0;
+
+	if (ip->i_diflags & XFS_DIFLAG_ANY) {
+		if (ip->i_diflags & XFS_DIFLAG_REALTIME)
+			flags |= FS_XFLAG_REALTIME;
+		if (ip->i_diflags & XFS_DIFLAG_PREALLOC)
+			flags |= FS_XFLAG_PREALLOC;
+		if (ip->i_diflags & XFS_DIFLAG_IMMUTABLE)
+			flags |= FS_XFLAG_IMMUTABLE;
+		if (ip->i_diflags & XFS_DIFLAG_APPEND)
+			flags |= FS_XFLAG_APPEND;
+		if (ip->i_diflags & XFS_DIFLAG_SYNC)
+			flags |= FS_XFLAG_SYNC;
+		if (ip->i_diflags & XFS_DIFLAG_NOATIME)
+			flags |= FS_XFLAG_NOATIME;
+		if (ip->i_diflags & XFS_DIFLAG_NODUMP)
+			flags |= FS_XFLAG_NODUMP;
+		if (ip->i_diflags & XFS_DIFLAG_RTINHERIT)
+			flags |= FS_XFLAG_RTINHERIT;
+		if (ip->i_diflags & XFS_DIFLAG_PROJINHERIT)
+			flags |= FS_XFLAG_PROJINHERIT;
+		if (ip->i_diflags & XFS_DIFLAG_NOSYMLINKS)
+			flags |= FS_XFLAG_NOSYMLINKS;
+		if (ip->i_diflags & XFS_DIFLAG_EXTSIZE)
+			flags |= FS_XFLAG_EXTSIZE;
+		if (ip->i_diflags & XFS_DIFLAG_EXTSZINHERIT)
+			flags |= FS_XFLAG_EXTSZINHERIT;
+		if (ip->i_diflags & XFS_DIFLAG_NODEFRAG)
+			flags |= FS_XFLAG_NODEFRAG;
+		if (ip->i_diflags & XFS_DIFLAG_FILESTREAM)
+			flags |= FS_XFLAG_FILESTREAM;
+	}
+
+	if (ip->i_diflags2 & XFS_DIFLAG2_ANY) {
+		if (ip->i_diflags2 & XFS_DIFLAG2_DAX)
+			flags |= FS_XFLAG_DAX;
+		if (ip->i_diflags2 & XFS_DIFLAG2_COWEXTSIZE)
+			flags |= FS_XFLAG_COWEXTSIZE;
+	}
+
+	if (xfs_inode_has_attr_fork(ip))
+		flags |= FS_XFLAG_HASATTR;
+	return flags;
+}
+
+/*
+ * Lookups up an inode from "name". If ci_name is not NULL, then a CI match
+ * is allowed, otherwise it has to be an exact match. If a CI match is found,
+ * ci_name->name will point to a the actual name (caller must free) or
+ * will be set to NULL if an exact match is found.
+ */
+int
+xfs_lookup(
+	struct xfs_inode	*dp,
+	const struct xfs_name	*name,
+	struct xfs_inode	**ipp,
+	struct xfs_name		*ci_name)
+{
+	xfs_ino_t		inum;
+	int			error;
+
+	trace_xfs_lookup(dp, name);
+
+	if (xfs_is_shutdown(dp->i_mount))
+		return -EIO;
+
+	error = xfs_dir_lookup(NULL, dp, name, &inum, ci_name);
+	if (error)
+		goto out_unlock;
+
+	error = xfs_iget(dp->i_mount, NULL, inum, 0, 0, ipp);
+	if (error)
+		goto out_free_name;
+
+	return 0;
+
+out_free_name:
+	if (ci_name)
+		kmem_free(ci_name->name);
+out_unlock:
+	*ipp = NULL;
+	return error;
+}
+
+/* Propagate di_flags from a parent inode to a child inode. */
+static void
+xfs_inode_inherit_flags(
+	struct xfs_inode	*ip,
+	const struct xfs_inode	*pip)
+{
+	unsigned int		di_flags = 0;
+	xfs_failaddr_t		failaddr;
+	umode_t			mode = VFS_I(ip)->i_mode;
+
+	if (S_ISDIR(mode)) {
+		if (pip->i_diflags & XFS_DIFLAG_RTINHERIT)
+			di_flags |= XFS_DIFLAG_RTINHERIT;
+		if (pip->i_diflags & XFS_DIFLAG_EXTSZINHERIT) {
+			di_flags |= XFS_DIFLAG_EXTSZINHERIT;
+			ip->i_extsize = pip->i_extsize;
+		}
+		if (pip->i_diflags & XFS_DIFLAG_PROJINHERIT)
+			di_flags |= XFS_DIFLAG_PROJINHERIT;
+	} else if (S_ISREG(mode)) {
+		if ((pip->i_diflags & XFS_DIFLAG_RTINHERIT) &&
+		    xfs_has_realtime(ip->i_mount))
+			di_flags |= XFS_DIFLAG_REALTIME;
+		if (pip->i_diflags & XFS_DIFLAG_EXTSZINHERIT) {
+			di_flags |= XFS_DIFLAG_EXTSIZE;
+			ip->i_extsize = pip->i_extsize;
+		}
+	}
+	if ((pip->i_diflags & XFS_DIFLAG_NOATIME) &&
+	    xfs_inherit_noatime)
+		di_flags |= XFS_DIFLAG_NOATIME;
+	if ((pip->i_diflags & XFS_DIFLAG_NODUMP) &&
+	    xfs_inherit_nodump)
+		di_flags |= XFS_DIFLAG_NODUMP;
+	if ((pip->i_diflags & XFS_DIFLAG_SYNC) &&
+	    xfs_inherit_sync)
+		di_flags |= XFS_DIFLAG_SYNC;
+	if ((pip->i_diflags & XFS_DIFLAG_NOSYMLINKS) &&
+	    xfs_inherit_nosymlinks)
+		di_flags |= XFS_DIFLAG_NOSYMLINKS;
+	if ((pip->i_diflags & XFS_DIFLAG_NODEFRAG) &&
+	    xfs_inherit_nodefrag)
+		di_flags |= XFS_DIFLAG_NODEFRAG;
+	if (pip->i_diflags & XFS_DIFLAG_FILESTREAM)
+		di_flags |= XFS_DIFLAG_FILESTREAM;
+
+	ip->i_diflags |= di_flags;
+
+	/*
+	 * Inode verifiers on older kernels only check that the extent size
+	 * hint is an integer multiple of the rt extent size on realtime files.
+	 * They did not check the hint alignment on a directory with both
+	 * rtinherit and extszinherit flags set.  If the misaligned hint is
+	 * propagated from a directory into a new realtime file, new file
+	 * allocations will fail due to math errors in the rt allocator and/or
+	 * trip the verifiers.  Validate the hint settings in the new file so
+	 * that we don't let broken hints propagate.
+	 */
+	failaddr = xfs_inode_validate_extsize(ip->i_mount, ip->i_extsize,
+			VFS_I(ip)->i_mode, ip->i_diflags);
+	if (failaddr) {
+		ip->i_diflags &= ~(XFS_DIFLAG_EXTSIZE |
+				   XFS_DIFLAG_EXTSZINHERIT);
+		ip->i_extsize = 0;
+	}
+}
+
+/* Propagate di_flags2 from a parent inode to a child inode. */
+static void
+xfs_inode_inherit_flags2(
+	struct xfs_inode	*ip,
+	const struct xfs_inode	*pip)
+{
+	xfs_failaddr_t		failaddr;
+
+	if (pip->i_diflags2 & XFS_DIFLAG2_COWEXTSIZE) {
+		ip->i_diflags2 |= XFS_DIFLAG2_COWEXTSIZE;
+		ip->i_cowextsize = pip->i_cowextsize;
+	}
+	if (pip->i_diflags2 & XFS_DIFLAG2_DAX)
+		ip->i_diflags2 |= XFS_DIFLAG2_DAX;
+
+	/* Don't let invalid cowextsize hints propagate. */
+	failaddr = xfs_inode_validate_cowextsize(ip->i_mount, ip->i_cowextsize,
+			VFS_I(ip)->i_mode, ip->i_diflags, ip->i_diflags2);
+	if (failaddr) {
+		ip->i_diflags2 &= ~XFS_DIFLAG2_COWEXTSIZE;
+		ip->i_cowextsize = 0;
+	}
+}
+
+/*
+ * Initialise a newly allocated inode and return the in-core inode to the
+ * caller locked exclusively.
+ */
+int
+xfs_init_new_inode(
+	struct user_namespace	*mnt_userns,
+	struct xfs_trans	*tp,
+	struct xfs_inode	*pip,
+	xfs_ino_t		ino,
+	umode_t			mode,
+	xfs_nlink_t		nlink,
+	dev_t			rdev,
+	prid_t			prid,
+	bool			init_xattrs,
+	struct xfs_inode	**ipp)
+{
+	struct inode		*dir = pip ? VFS_I(pip) : NULL;
+	struct xfs_mount	*mp = tp->t_mountp;
+	struct xfs_inode	*ip;
+	unsigned int		flags;
+	int			error;
+	struct timespec64	tv;
+	struct inode		*inode;
+
+	/*
+	 * Protect against obviously corrupt allocation btree records. Later
+	 * xfs_iget checks will catch re-allocation of other active in-memory
+	 * and on-disk inodes. If we don't catch reallocating the parent inode
+	 * here we will deadlock in xfs_iget() so we have to do these checks
+	 * first.
+	 */
+	if ((pip && ino == pip->i_ino) || !xfs_verify_dir_ino(mp, ino)) {
+		xfs_alert(mp, "Allocated a known in-use inode 0x%llx!", ino);
+		return -EFSCORRUPTED;
+	}
+
+	/*
+	 * Get the in-core inode with the lock held exclusively to prevent
+	 * others from looking at until we're done.
+	 */
+	error = xfs_iget(mp, tp, ino, XFS_IGET_CREATE, XFS_ILOCK_EXCL, &ip);
+	if (error)
+		return error;
+
+	ASSERT(ip != NULL);
+	inode = VFS_I(ip);
+	set_nlink(inode, nlink);
+	inode->i_rdev = rdev;
+	ip->i_projid = prid;
+
+	if (dir && !(dir->i_mode & S_ISGID) && xfs_has_grpid(mp)) {
+		inode_fsuid_set(inode, mnt_userns);
+		inode->i_gid = dir->i_gid;
+		inode->i_mode = mode;
+	} else {
+		inode_init_owner(mnt_userns, inode, dir, mode);
+	}
+
+	/*
+	 * If the group ID of the new file does not match the effective group
+	 * ID or one of the supplementary group IDs, the S_ISGID bit is cleared
+	 * (and only if the irix_sgid_inherit compatibility variable is set).
+	 */
+	if (irix_sgid_inherit && (inode->i_mode & S_ISGID) &&
+	    !vfsgid_in_group_p(i_gid_into_vfsgid(mnt_userns, inode)))
+		inode->i_mode &= ~S_ISGID;
+
+	ip->i_disk_size = 0;
+	ip->i_df.if_nextents = 0;
+	ASSERT(ip->i_nblocks == 0);
+
+	tv = current_time(inode);
+	inode->i_mtime = tv;
+	inode->i_atime = tv;
+	inode->i_ctime = tv;
+
+	ip->i_extsize = 0;
+	ip->i_diflags = 0;
+
+	if (xfs_has_v3inodes(mp)) {
+		inode_set_iversion(inode, 1);
+		ip->i_cowextsize = 0;
+		ip->i_crtime = tv;
+	}
+
+	flags = XFS_ILOG_CORE;
+	switch (mode & S_IFMT) {
+	case S_IFIFO:
+	case S_IFCHR:
+	case S_IFBLK:
+	case S_IFSOCK:
+		ip->i_df.if_format = XFS_DINODE_FMT_DEV;
+		flags |= XFS_ILOG_DEV;
+		break;
+	case S_IFREG:
+	case S_IFDIR:
+		if (pip && (pip->i_diflags & XFS_DIFLAG_ANY))
+			xfs_inode_inherit_flags(ip, pip);
+		if (pip && (pip->i_diflags2 & XFS_DIFLAG2_ANY))
+			xfs_inode_inherit_flags2(ip, pip);
+		fallthrough;
+	case S_IFLNK:
+		ip->i_df.if_format = XFS_DINODE_FMT_EXTENTS;
+		ip->i_df.if_bytes = 0;
+		ip->i_df.if_u1.if_root = NULL;
+		break;
+	default:
+		ASSERT(0);
+	}
+
+	/*
+	 * If we need to create attributes immediately after allocating the
+	 * inode, initialise an empty attribute fork right now. We use the
+	 * default fork offset for attributes here as we don't know exactly what
+	 * size or how many attributes we might be adding. We can do this
+	 * safely here because we know the data fork is completely empty and
+	 * this saves us from needing to run a separate transaction to set the
+	 * fork offset in the immediate future.
+	 */
+	if (init_xattrs && xfs_has_attr(mp)) {
+		ip->i_forkoff = xfs_default_attroffset(ip) >> 3;
+		xfs_ifork_init_attr(ip, XFS_DINODE_FMT_EXTENTS, 0);
+	}
+
+	/*
+	 * Log the new values stuffed into the inode.
+	 */
+	xfs_trans_ijoin(tp, ip, XFS_ILOCK_EXCL);
+	xfs_trans_log_inode(tp, ip, flags);
+
+	/* now that we have an i_mode we can setup the inode structure */
+	xfs_setup_inode(ip);
+
+	*ipp = ip;
+	return 0;
+}
+
+/*
+ * Decrement the link count on an inode & log the change.  If this causes the
+ * link count to go to zero, move the inode to AGI unlinked list so that it can
+ * be freed when the last active reference goes away via xfs_inactive().
+ */
+static int			/* error */
+xfs_droplink(
+	xfs_trans_t *tp,
+	xfs_inode_t *ip)
+{
+	xfs_trans_ichgtime(tp, ip, XFS_ICHGTIME_CHG);
+
+	drop_nlink(VFS_I(ip));
+	xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
+
+	if (VFS_I(ip)->i_nlink)
+		return 0;
+
+	return xfs_iunlink(tp, ip);
+}
+
+/*
+ * Increment the link count on an inode & log the change.
+ */
+static void
+xfs_bumplink(
+	xfs_trans_t *tp,
+	xfs_inode_t *ip)
+{
+	xfs_trans_ichgtime(tp, ip, XFS_ICHGTIME_CHG);
+
+	inc_nlink(VFS_I(ip));
+	xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
+}
+
+int
+xfs_create(
+	struct user_namespace	*mnt_userns,
+	xfs_inode_t		*dp,
+	struct xfs_name		*name,
+	umode_t			mode,
+	dev_t			rdev,
+	bool			init_xattrs,
+	xfs_inode_t		**ipp)
+{
+	int			is_dir = S_ISDIR(mode);
+	struct xfs_mount	*mp = dp->i_mount;
+	struct xfs_inode	*ip = NULL;
+	struct xfs_trans	*tp = NULL;
+	int			error;
+	bool                    unlock_dp_on_error = false;
+	prid_t			prid;
+	struct xfs_dquot	*udqp = NULL;
+	struct xfs_dquot	*gdqp = NULL;
+	struct xfs_dquot	*pdqp = NULL;
+	struct xfs_trans_res	*tres;
+	uint			resblks;
+	xfs_ino_t		ino;
+
+	trace_xfs_create(dp, name);
+
+	if (xfs_is_shutdown(mp))
+		return -EIO;
+
+	prid = xfs_get_initial_prid(dp);
+
+	/*
+	 * Make sure that we have allocated dquot(s) on disk.
+	 */
+	error = xfs_qm_vop_dqalloc(dp, mapped_fsuid(mnt_userns, &init_user_ns),
+			mapped_fsgid(mnt_userns, &init_user_ns), prid,
+			XFS_QMOPT_QUOTALL | XFS_QMOPT_INHERIT,
+			&udqp, &gdqp, &pdqp);
+	if (error)
+		return error;
+
+	if (is_dir) {
+		resblks = XFS_MKDIR_SPACE_RES(mp, name->len);
+		tres = &M_RES(mp)->tr_mkdir;
+	} else {
+		resblks = XFS_CREATE_SPACE_RES(mp, name->len);
+		tres = &M_RES(mp)->tr_create;
+	}
+
+	/*
+	 * Initially assume that the file does not exist and
+	 * reserve the resources for that case.  If that is not
+	 * the case we'll drop the one we have and get a more
+	 * appropriate transaction later.
+	 */
+	error = xfs_trans_alloc_icreate(mp, tres, udqp, gdqp, pdqp, resblks,
+			&tp);
+	if (error == -ENOSPC) {
+		/* flush outstanding delalloc blocks and retry */
+		xfs_flush_inodes(mp);
+		error = xfs_trans_alloc_icreate(mp, tres, udqp, gdqp, pdqp,
+				resblks, &tp);
+	}
+	if (error)
+		goto out_release_dquots;
+
+	xfs_ilock(dp, XFS_ILOCK_EXCL | XFS_ILOCK_PARENT);
+	unlock_dp_on_error = true;
+
+	/*
+	 * A newly created regular or special file just has one directory
+	 * entry pointing to them, but a directory also the "." entry
+	 * pointing to itself.
+	 */
+	error = xfs_dialloc(&tp, dp->i_ino, mode, &ino);
+	if (!error)
+		error = xfs_init_new_inode(mnt_userns, tp, dp, ino, mode,
+				is_dir ? 2 : 1, rdev, prid, init_xattrs, &ip);
+	if (error)
+		goto out_trans_cancel;
+
+	/*
+	 * Now we join the directory inode to the transaction.  We do not do it
+	 * earlier because xfs_dialloc might commit the previous transaction
+	 * (and release all the locks).  An error from here on will result in
+	 * the transaction cancel unlocking dp so don't do it explicitly in the
+	 * error path.
+	 */
+	xfs_trans_ijoin(tp, dp, XFS_ILOCK_EXCL);
+	unlock_dp_on_error = false;
+
+	error = xfs_dir_createname(tp, dp, name, ip->i_ino,
+					resblks - XFS_IALLOC_SPACE_RES(mp));
+	if (error) {
+		ASSERT(error != -ENOSPC);
+		goto out_trans_cancel;
+	}
+	xfs_trans_ichgtime(tp, dp, XFS_ICHGTIME_MOD | XFS_ICHGTIME_CHG);
+	xfs_trans_log_inode(tp, dp, XFS_ILOG_CORE);
+
+	if (is_dir) {
+		error = xfs_dir_init(tp, ip, dp);
+		if (error)
+			goto out_trans_cancel;
+
+		xfs_bumplink(tp, dp);
+	}
+
+	/*
+	 * If this is a synchronous mount, make sure that the
+	 * create transaction goes to disk before returning to
+	 * the user.
+	 */
+	if (xfs_has_wsync(mp) || xfs_has_dirsync(mp))
+		xfs_trans_set_sync(tp);
+
+	/*
+	 * Attach the dquot(s) to the inodes and modify them incore.
+	 * These ids of the inode couldn't have changed since the new
+	 * inode has been locked ever since it was created.
+	 */
+	xfs_qm_vop_create_dqattach(tp, ip, udqp, gdqp, pdqp);
+
+	error = xfs_trans_commit(tp);
+	if (error)
+		goto out_release_inode;
+
+	xfs_qm_dqrele(udqp);
+	xfs_qm_dqrele(gdqp);
+	xfs_qm_dqrele(pdqp);
+
+	*ipp = ip;
+	return 0;
+
+ out_trans_cancel:
+	xfs_trans_cancel(tp);
+ out_release_inode:
+	/*
+	 * Wait until after the current transaction is aborted to finish the
+	 * setup of the inode and release the inode.  This prevents recursive
+	 * transactions and deadlocks from xfs_inactive.
+	 */
+	if (ip) {
+		xfs_finish_inode_setup(ip);
+		xfs_irele(ip);
+	}
+ out_release_dquots:
+	xfs_qm_dqrele(udqp);
+	xfs_qm_dqrele(gdqp);
+	xfs_qm_dqrele(pdqp);
+
+	if (unlock_dp_on_error)
+		xfs_iunlock(dp, XFS_ILOCK_EXCL);
+	return error;
+}
+
+int
+xfs_create_tmpfile(
+	struct user_namespace	*mnt_userns,
+	struct xfs_inode	*dp,
+	umode_t			mode,
+	struct xfs_inode	**ipp)
+{
+	struct xfs_mount	*mp = dp->i_mount;
+	struct xfs_inode	*ip = NULL;
+	struct xfs_trans	*tp = NULL;
+	int			error;
+	prid_t                  prid;
+	struct xfs_dquot	*udqp = NULL;
+	struct xfs_dquot	*gdqp = NULL;
+	struct xfs_dquot	*pdqp = NULL;
+	struct xfs_trans_res	*tres;
+	uint			resblks;
+	xfs_ino_t		ino;
+
+	if (xfs_is_shutdown(mp))
+		return -EIO;
+
+	prid = xfs_get_initial_prid(dp);
+
+	/*
+	 * Make sure that we have allocated dquot(s) on disk.
+	 */
+	error = xfs_qm_vop_dqalloc(dp, mapped_fsuid(mnt_userns, &init_user_ns),
+			mapped_fsgid(mnt_userns, &init_user_ns), prid,
+			XFS_QMOPT_QUOTALL | XFS_QMOPT_INHERIT,
+			&udqp, &gdqp, &pdqp);
+	if (error)
+		return error;
+
+	resblks = XFS_IALLOC_SPACE_RES(mp);
+	tres = &M_RES(mp)->tr_create_tmpfile;
+
+	error = xfs_trans_alloc_icreate(mp, tres, udqp, gdqp, pdqp, resblks,
+			&tp);
+	if (error)
+		goto out_release_dquots;
+
+	error = xfs_dialloc(&tp, dp->i_ino, mode, &ino);
+	if (!error)
+		error = xfs_init_new_inode(mnt_userns, tp, dp, ino, mode,
+				0, 0, prid, false, &ip);
+	if (error)
+		goto out_trans_cancel;
+
+	if (xfs_has_wsync(mp))
+		xfs_trans_set_sync(tp);
+
+	/*
+	 * Attach the dquot(s) to the inodes and modify them incore.
+	 * These ids of the inode couldn't have changed since the new
+	 * inode has been locked ever since it was created.
+	 */
+	xfs_qm_vop_create_dqattach(tp, ip, udqp, gdqp, pdqp);
+
+	error = xfs_iunlink(tp, ip);
+	if (error)
+		goto out_trans_cancel;
+
+	error = xfs_trans_commit(tp);
+	if (error)
+		goto out_release_inode;
+
+	xfs_qm_dqrele(udqp);
+	xfs_qm_dqrele(gdqp);
+	xfs_qm_dqrele(pdqp);
+
+	*ipp = ip;
+	return 0;
+
+ out_trans_cancel:
+	xfs_trans_cancel(tp);
+ out_release_inode:
+	/*
+	 * Wait until after the current transaction is aborted to finish the
+	 * setup of the inode and release the inode.  This prevents recursive
+	 * transactions and deadlocks from xfs_inactive.
+	 */
+	if (ip) {
+		xfs_finish_inode_setup(ip);
+		xfs_irele(ip);
+	}
+ out_release_dquots:
+	xfs_qm_dqrele(udqp);
+	xfs_qm_dqrele(gdqp);
+	xfs_qm_dqrele(pdqp);
+
+	return error;
+}
+
+int
+xfs_link(
+	xfs_inode_t		*tdp,
+	xfs_inode_t		*sip,
+	struct xfs_name		*target_name)
+{
+	xfs_mount_t		*mp = tdp->i_mount;
+	xfs_trans_t		*tp;
+	int			error, nospace_error = 0;
+	int			resblks;
+
+	trace_xfs_link(tdp, target_name);
+
+	ASSERT(!S_ISDIR(VFS_I(sip)->i_mode));
+
+	if (xfs_is_shutdown(mp))
+		return -EIO;
+
+	error = xfs_qm_dqattach(sip);
+	if (error)
+		goto std_return;
+
+	error = xfs_qm_dqattach(tdp);
+	if (error)
+		goto std_return;
+
+	resblks = XFS_LINK_SPACE_RES(mp, target_name->len);
+	error = xfs_trans_alloc_dir(tdp, &M_RES(mp)->tr_link, sip, &resblks,
+			&tp, &nospace_error);
+	if (error)
+		goto std_return;
+
+	/*
+	 * If we are using project inheritance, we only allow hard link
+	 * creation in our tree when the project IDs are the same; else
+	 * the tree quota mechanism could be circumvented.
+	 */
+	if (unlikely((tdp->i_diflags & XFS_DIFLAG_PROJINHERIT) &&
+		     tdp->i_projid != sip->i_projid)) {
+		error = -EXDEV;
+		goto error_return;
+	}
+
+	if (!resblks) {
+		error = xfs_dir_canenter(tp, tdp, target_name);
+		if (error)
+			goto error_return;
+	}
+
+	/*
+	 * Handle initial link state of O_TMPFILE inode
+	 */
+	if (VFS_I(sip)->i_nlink == 0) {
+		struct xfs_perag	*pag;
+
+		pag = xfs_perag_get(mp, XFS_INO_TO_AGNO(mp, sip->i_ino));
+		error = xfs_iunlink_remove(tp, pag, sip);
+		xfs_perag_put(pag);
+		if (error)
+			goto error_return;
+	}
+
+	error = xfs_dir_createname(tp, tdp, target_name, sip->i_ino,
+				   resblks);
+	if (error)
+		goto error_return;
+	xfs_trans_ichgtime(tp, tdp, XFS_ICHGTIME_MOD | XFS_ICHGTIME_CHG);
+	xfs_trans_log_inode(tp, tdp, XFS_ILOG_CORE);
+
+	xfs_bumplink(tp, sip);
+
+	/*
+	 * If this is a synchronous mount, make sure that the
+	 * link transaction goes to disk before returning to
+	 * the user.
+	 */
+	if (xfs_has_wsync(mp) || xfs_has_dirsync(mp))
+		xfs_trans_set_sync(tp);
+
+	return xfs_trans_commit(tp);
+
+ error_return:
+	xfs_trans_cancel(tp);
+ std_return:
+	if (error == -ENOSPC && nospace_error)
+		error = nospace_error;
+	return error;
+}
+
+/* Clear the reflink flag and the cowblocks tag if possible. */
+static void
+xfs_itruncate_clear_reflink_flags(
+	struct xfs_inode	*ip)
+{
+	struct xfs_ifork	*dfork;
+	struct xfs_ifork	*cfork;
+
+	if (!xfs_is_reflink_inode(ip))
+		return;
+	dfork = xfs_ifork_ptr(ip, XFS_DATA_FORK);
+	cfork = xfs_ifork_ptr(ip, XFS_COW_FORK);
+	if (dfork->if_bytes == 0 && cfork->if_bytes == 0)
+		ip->i_diflags2 &= ~XFS_DIFLAG2_REFLINK;
+	if (cfork->if_bytes == 0)
+		xfs_inode_clear_cowblocks_tag(ip);
+}
+
+/*
+ * Free up the underlying blocks past new_size.  The new size must be smaller
+ * than the current size.  This routine can be used both for the attribute and
+ * data fork, and does not modify the inode size, which is left to the caller.
+ *
+ * The transaction passed to this routine must have made a permanent log
+ * reservation of at least XFS_ITRUNCATE_LOG_RES.  This routine may commit the
+ * given transaction and start new ones, so make sure everything involved in
+ * the transaction is tidy before calling here.  Some transaction will be
+ * returned to the caller to be committed.  The incoming transaction must
+ * already include the inode, and both inode locks must be held exclusively.
+ * The inode must also be "held" within the transaction.  On return the inode
+ * will be "held" within the returned transaction.  This routine does NOT
+ * require any disk space to be reserved for it within the transaction.
+ *
+ * If we get an error, we must return with the inode locked and linked into the
+ * current transaction. This keeps things simple for the higher level code,
+ * because it always knows that the inode is locked and held in the transaction
+ * that returns to it whether errors occur or not.  We don't mark the inode
+ * dirty on error so that transactions can be easily aborted if possible.
+ */
+int
+xfs_itruncate_extents_flags(
+	struct xfs_trans	**tpp,
+	struct xfs_inode	*ip,
+	int			whichfork,
+	xfs_fsize_t		new_size,
+	int			flags)
+{
+	struct xfs_mount	*mp = ip->i_mount;
+	struct xfs_trans	*tp = *tpp;
+	xfs_fileoff_t		first_unmap_block;
+	xfs_filblks_t		unmap_len;
+	int			error = 0;
+
+	ASSERT(xfs_isilocked(ip, XFS_ILOCK_EXCL));
+	ASSERT(!atomic_read(&VFS_I(ip)->i_count) ||
+	       xfs_isilocked(ip, XFS_IOLOCK_EXCL));
+	ASSERT(new_size <= XFS_ISIZE(ip));
+	ASSERT(tp->t_flags & XFS_TRANS_PERM_LOG_RES);
+	ASSERT(ip->i_itemp != NULL);
+	ASSERT(ip->i_itemp->ili_lock_flags == 0);
+	ASSERT(!XFS_NOT_DQATTACHED(mp, ip));
+
+	trace_xfs_itruncate_extents_start(ip, new_size);
+
+	flags |= xfs_bmapi_aflag(whichfork);
+
+	/*
+	 * Since it is possible for space to become allocated beyond
+	 * the end of the file (in a crash where the space is allocated
+	 * but the inode size is not yet updated), simply remove any
+	 * blocks which show up between the new EOF and the maximum
+	 * possible file size.
+	 *
+	 * We have to free all the blocks to the bmbt maximum offset, even if
+	 * the page cache can't scale that far.
+	 */
+	first_unmap_block = XFS_B_TO_FSB(mp, (xfs_ufsize_t)new_size);
+	if (!xfs_verify_fileoff(mp, first_unmap_block)) {
+		WARN_ON_ONCE(first_unmap_block > XFS_MAX_FILEOFF);
+		return 0;
+	}
+
+	unmap_len = XFS_MAX_FILEOFF - first_unmap_block + 1;
+	while (unmap_len > 0) {
+		ASSERT(tp->t_firstblock == NULLFSBLOCK);
+		error = __xfs_bunmapi(tp, ip, first_unmap_block, &unmap_len,
+				flags, XFS_ITRUNC_MAX_EXTENTS);
+		if (error)
+			goto out;
+
+		/* free the just unmapped extents */
+		error = xfs_defer_finish(&tp);
+		if (error)
+			goto out;
+	}
+
+	if (whichfork == XFS_DATA_FORK) {
+		/* Remove all pending CoW reservations. */
+		error = xfs_reflink_cancel_cow_blocks(ip, &tp,
+				first_unmap_block, XFS_MAX_FILEOFF, true);
+		if (error)
+			goto out;
+
+		xfs_itruncate_clear_reflink_flags(ip);
+	}
+
+	/*
+	 * Always re-log the inode so that our permanent transaction can keep
+	 * on rolling it forward in the log.
+	 */
+	xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
+
+	trace_xfs_itruncate_extents_end(ip, new_size);
+
+out:
+	*tpp = tp;
+	return error;
+}
+
+int
+xfs_release(
+	xfs_inode_t	*ip)
+{
+	xfs_mount_t	*mp = ip->i_mount;
+	int		error = 0;
+
+	if (!S_ISREG(VFS_I(ip)->i_mode) || (VFS_I(ip)->i_mode == 0))
+		return 0;
+
+	/* If this is a read-only mount, don't do this (would generate I/O) */
+	if (xfs_is_readonly(mp))
+		return 0;
+
+	if (!xfs_is_shutdown(mp)) {
+		int truncated;
+
+		/*
+		 * If we previously truncated this file and removed old data
+		 * in the process, we want to initiate "early" writeout on
+		 * the last close.  This is an attempt to combat the notorious
+		 * NULL files problem which is particularly noticeable from a
+		 * truncate down, buffered (re-)write (delalloc), followed by
+		 * a crash.  What we are effectively doing here is
+		 * significantly reducing the time window where we'd otherwise
+		 * be exposed to that problem.
+		 */
+		truncated = xfs_iflags_test_and_clear(ip, XFS_ITRUNCATED);
+		if (truncated) {
+			xfs_iflags_clear(ip, XFS_IDIRTY_RELEASE);
+			if (ip->i_delayed_blks > 0) {
+				error = filemap_flush(VFS_I(ip)->i_mapping);
+				if (error)
+					return error;
+			}
+		}
+	}
+
+	if (VFS_I(ip)->i_nlink == 0)
+		return 0;
+
+	/*
+	 * If we can't get the iolock just skip truncating the blocks past EOF
+	 * because we could deadlock with the mmap_lock otherwise. We'll get
+	 * another chance to drop them once the last reference to the inode is
+	 * dropped, so we'll never leak blocks permanently.
+	 */
+	if (!xfs_ilock_nowait(ip, XFS_IOLOCK_EXCL))
+		return 0;
+
+	if (xfs_can_free_eofblocks(ip, false)) {
+		/*
+		 * Check if the inode is being opened, written and closed
+		 * frequently and we have delayed allocation blocks outstanding
+		 * (e.g. streaming writes from the NFS server), truncating the
+		 * blocks past EOF will cause fragmentation to occur.
+		 *
+		 * In this case don't do the truncation, but we have to be
+		 * careful how we detect this case. Blocks beyond EOF show up as
+		 * i_delayed_blks even when the inode is clean, so we need to
+		 * truncate them away first before checking for a dirty release.
+		 * Hence on the first dirty close we will still remove the
+		 * speculative allocation, but after that we will leave it in
+		 * place.
+		 */
+		if (xfs_iflags_test(ip, XFS_IDIRTY_RELEASE))
+			goto out_unlock;
+
+		error = xfs_free_eofblocks(ip);
+		if (error)
+			goto out_unlock;
+
+		/* delalloc blocks after truncation means it really is dirty */
+		if (ip->i_delayed_blks)
+			xfs_iflags_set(ip, XFS_IDIRTY_RELEASE);
+	}
+
+out_unlock:
+	xfs_iunlock(ip, XFS_IOLOCK_EXCL);
+	return error;
+}
+
+/*
+ * xfs_inactive_truncate
+ *
+ * Called to perform a truncate when an inode becomes unlinked.
+ */
+STATIC int
+xfs_inactive_truncate(
+	struct xfs_inode *ip)
+{
+	struct xfs_mount	*mp = ip->i_mount;
+	struct xfs_trans	*tp;
+	int			error;
+
+	error = xfs_trans_alloc(mp, &M_RES(mp)->tr_itruncate, 0, 0, 0, &tp);
+	if (error) {
+		ASSERT(xfs_is_shutdown(mp));
+		return error;
+	}
+	xfs_ilock(ip, XFS_ILOCK_EXCL);
+	xfs_trans_ijoin(tp, ip, 0);
+
+	/*
+	 * Log the inode size first to prevent stale data exposure in the event
+	 * of a system crash before the truncate completes. See the related
+	 * comment in xfs_vn_setattr_size() for details.
+	 */
+	ip->i_disk_size = 0;
+	xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
+
+	error = xfs_itruncate_extents(&tp, ip, XFS_DATA_FORK, 0);
+	if (error)
+		goto error_trans_cancel;
+
+	ASSERT(ip->i_df.if_nextents == 0);
+
+	error = xfs_trans_commit(tp);
+	if (error)
+		goto error_unlock;
+
+	xfs_iunlock(ip, XFS_ILOCK_EXCL);
+	return 0;
+
+error_trans_cancel:
+	xfs_trans_cancel(tp);
+error_unlock:
+	xfs_iunlock(ip, XFS_ILOCK_EXCL);
+	return error;
+}
+
+/*
+ * xfs_inactive_ifree()
+ *
+ * Perform the inode free when an inode is unlinked.
+ */
+STATIC int
+xfs_inactive_ifree(
+	struct xfs_inode *ip)
+{
+	struct xfs_mount	*mp = ip->i_mount;
+	struct xfs_trans	*tp;
+	int			error;
+
+	/*
+	 * We try to use a per-AG reservation for any block needed by the finobt
+	 * tree, but as the finobt feature predates the per-AG reservation
+	 * support a degraded file system might not have enough space for the
+	 * reservation at mount time.  In that case try to dip into the reserved
+	 * pool and pray.
+	 *
+	 * Send a warning if the reservation does happen to fail, as the inode
+	 * now remains allocated and sits on the unlinked list until the fs is
+	 * repaired.
+	 */
+	if (unlikely(mp->m_finobt_nores)) {
+		error = xfs_trans_alloc(mp, &M_RES(mp)->tr_ifree,
+				XFS_IFREE_SPACE_RES(mp), 0, XFS_TRANS_RESERVE,
+				&tp);
+	} else {
+		error = xfs_trans_alloc(mp, &M_RES(mp)->tr_ifree, 0, 0, 0, &tp);
+	}
+	if (error) {
+		if (error == -ENOSPC) {
+			xfs_warn_ratelimited(mp,
+			"Failed to remove inode(s) from unlinked list. "
+			"Please free space, unmount and run xfs_repair.");
+		} else {
+			ASSERT(xfs_is_shutdown(mp));
+		}
+		return error;
+	}
+
+	/*
+	 * We do not hold the inode locked across the entire rolling transaction
+	 * here. We only need to hold it for the first transaction that
+	 * xfs_ifree() builds, which may mark the inode XFS_ISTALE if the
+	 * underlying cluster buffer is freed. Relogging an XFS_ISTALE inode
+	 * here breaks the relationship between cluster buffer invalidation and
+	 * stale inode invalidation on cluster buffer item journal commit
+	 * completion, and can result in leaving dirty stale inodes hanging
+	 * around in memory.
+	 *
+	 * We have no need for serialising this inode operation against other
+	 * operations - we freed the inode and hence reallocation is required
+	 * and that will serialise on reallocating the space the deferops need
+	 * to free. Hence we can unlock the inode on the first commit of
+	 * the transaction rather than roll it right through the deferops. This
+	 * avoids relogging the XFS_ISTALE inode.
+	 *
+	 * We check that xfs_ifree() hasn't grown an internal transaction roll
+	 * by asserting that the inode is still locked when it returns.
+	 */
+	xfs_ilock(ip, XFS_ILOCK_EXCL);
+	xfs_trans_ijoin(tp, ip, XFS_ILOCK_EXCL);
+
+	error = xfs_ifree(tp, ip);
+	ASSERT(xfs_isilocked(ip, XFS_ILOCK_EXCL));
+	if (error) {
+		/*
+		 * If we fail to free the inode, shut down.  The cancel
+		 * might do that, we need to make sure.  Otherwise the
+		 * inode might be lost for a long time or forever.
+		 */
+		if (!xfs_is_shutdown(mp)) {
+			xfs_notice(mp, "%s: xfs_ifree returned error %d",
+				__func__, error);
+			xfs_force_shutdown(mp, SHUTDOWN_META_IO_ERROR);
+		}
+		xfs_trans_cancel(tp);
+		return error;
+	}
+
+	/*
+	 * Credit the quota account(s). The inode is gone.
+	 */
+	xfs_trans_mod_dquot_byino(tp, ip, XFS_TRANS_DQ_ICOUNT, -1);
+
+	/*
+	 * Just ignore errors at this point.  There is nothing we can do except
+	 * to try to keep going. Make sure it's not a silent error.
+	 */
+	error = xfs_trans_commit(tp);
+	if (error)
+		xfs_notice(mp, "%s: xfs_trans_commit returned error %d",
+			__func__, error);
+
+	return 0;
+}
+
+/*
+ * Returns true if we need to update the on-disk metadata before we can free
+ * the memory used by this inode.  Updates include freeing post-eof
+ * preallocations; freeing COW staging extents; and marking the inode free in
+ * the inobt if it is on the unlinked list.
+ */
+bool
+xfs_inode_needs_inactive(
+	struct xfs_inode	*ip)
+{
+	struct xfs_mount	*mp = ip->i_mount;
+	struct xfs_ifork	*cow_ifp = xfs_ifork_ptr(ip, XFS_COW_FORK);
+
+	/*
+	 * If the inode is already free, then there can be nothing
+	 * to clean up here.
+	 */
+	if (VFS_I(ip)->i_mode == 0)
+		return false;
+
+	/* If this is a read-only mount, don't do this (would generate I/O) */
+	if (xfs_is_readonly(mp))
+		return false;
+
+	/* If the log isn't running, push inodes straight to reclaim. */
+	if (xfs_is_shutdown(mp) || xfs_has_norecovery(mp))
+		return false;
+
+	/* Metadata inodes require explicit resource cleanup. */
+	if (xfs_is_metadata_inode(ip))
+		return false;
+
+	/* Want to clean out the cow blocks if there are any. */
+	if (cow_ifp && cow_ifp->if_bytes > 0)
+		return true;
+
+	/* Unlinked files must be freed. */
+	if (VFS_I(ip)->i_nlink == 0)
+		return true;
+
+	/*
+	 * This file isn't being freed, so check if there are post-eof blocks
+	 * to free.  @force is true because we are evicting an inode from the
+	 * cache.  Post-eof blocks must be freed, lest we end up with broken
+	 * free space accounting.
+	 *
+	 * Note: don't bother with iolock here since lockdep complains about
+	 * acquiring it in reclaim context. We have the only reference to the
+	 * inode at this point anyways.
+	 */
+	return xfs_can_free_eofblocks(ip, true);
+}
+
+/*
+ * xfs_inactive
+ *
+ * This is called when the vnode reference count for the vnode
+ * goes to zero.  If the file has been unlinked, then it must
+ * now be truncated.  Also, we clear all of the read-ahead state
+ * kept for the inode here since the file is now closed.
+ */
+void
+xfs_inactive(
+	xfs_inode_t	*ip)
+{
+	struct xfs_mount	*mp;
+	int			error;
+	int			truncate = 0;
+
+	/*
+	 * If the inode is already free, then there can be nothing
+	 * to clean up here.
+	 */
+	if (VFS_I(ip)->i_mode == 0) {
+		ASSERT(ip->i_df.if_broot_bytes == 0);
+		goto out;
+	}
+
+	mp = ip->i_mount;
+	ASSERT(!xfs_iflags_test(ip, XFS_IRECOVERY));
+
+	/* If this is a read-only mount, don't do this (would generate I/O) */
+	if (xfs_is_readonly(mp))
+		goto out;
+
+	/* Metadata inodes require explicit resource cleanup. */
+	if (xfs_is_metadata_inode(ip))
+		goto out;
+
+	/* Try to clean out the cow blocks if there are any. */
+	if (xfs_inode_has_cow_data(ip))
+		xfs_reflink_cancel_cow_range(ip, 0, NULLFILEOFF, true);
+
+	if (VFS_I(ip)->i_nlink != 0) {
+		/*
+		 * force is true because we are evicting an inode from the
+		 * cache. Post-eof blocks must be freed, lest we end up with
+		 * broken free space accounting.
+		 *
+		 * Note: don't bother with iolock here since lockdep complains
+		 * about acquiring it in reclaim context. We have the only
+		 * reference to the inode at this point anyways.
+		 */
+		if (xfs_can_free_eofblocks(ip, true))
+			xfs_free_eofblocks(ip);
+
+		goto out;
+	}
+
+	if (S_ISREG(VFS_I(ip)->i_mode) &&
+	    (ip->i_disk_size != 0 || XFS_ISIZE(ip) != 0 ||
+	     ip->i_df.if_nextents > 0 || ip->i_delayed_blks > 0))
+		truncate = 1;
+
+	error = xfs_qm_dqattach(ip);
+	if (error)
+		goto out;
+
+	if (S_ISLNK(VFS_I(ip)->i_mode))
+		error = xfs_inactive_symlink(ip);
+	else if (truncate)
+		error = xfs_inactive_truncate(ip);
+	if (error)
+		goto out;
+
+	/*
+	 * If there are attributes associated with the file then blow them away
+	 * now.  The code calls a routine that recursively deconstructs the
+	 * attribute fork. If also blows away the in-core attribute fork.
+	 */
+	if (xfs_inode_has_attr_fork(ip)) {
+		error = xfs_attr_inactive(ip);
+		if (error)
+			goto out;
+	}
+
+	ASSERT(ip->i_forkoff == 0);
+
+	/*
+	 * Free the inode.
+	 */
+	xfs_inactive_ifree(ip);
+
+out:
+	/*
+	 * We're done making metadata updates for this inode, so we can release
+	 * the attached dquots.
+	 */
+	xfs_qm_dqdetach(ip);
+}
+
+/*
+ * In-Core Unlinked List Lookups
+ * =============================
+ *
+ * Every inode is supposed to be reachable from some other piece of metadata
+ * with the exception of the root directory.  Inodes with a connection to a
+ * file descriptor but not linked from anywhere in the on-disk directory tree
+ * are collectively known as unlinked inodes, though the filesystem itself
+ * maintains links to these inodes so that on-disk metadata are consistent.
+ *
+ * XFS implements a per-AG on-disk hash table of unlinked inodes.  The AGI
+ * header contains a number of buckets that point to an inode, and each inode
+ * record has a pointer to the next inode in the hash chain.  This
+ * singly-linked list causes scaling problems in the iunlink remove function
+ * because we must walk that list to find the inode that points to the inode
+ * being removed from the unlinked hash bucket list.
+ *
+ * Hence we keep an in-memory double linked list to link each inode on an
+ * unlinked list. Because there are 64 unlinked lists per AGI, keeping pointer
+ * based lists would require having 64 list heads in the perag, one for each
+ * list. This is expensive in terms of memory (think millions of AGs) and cache
+ * misses on lookups. Instead, use the fact that inodes on the unlinked list
+ * must be referenced at the VFS level to keep them on the list and hence we
+ * have an existence guarantee for inodes on the unlinked list.
+ *
+ * Given we have an existence guarantee, we can use lockless inode cache lookups
+ * to resolve aginos to xfs inodes. This means we only need 8 bytes per inode
+ * for the double linked unlinked list, and we don't need any extra locking to
+ * keep the list safe as all manipulations are done under the AGI buffer lock.
+ * Keeping the list up to date does not require memory allocation, just finding
+ * the XFS inode and updating the next/prev unlinked list aginos.
+ */
+
+/*
+ * Find an inode on the unlinked list. This does not take references to the
+ * inode as we have existence guarantees by holding the AGI buffer lock and that
+ * only unlinked, referenced inodes can be on the unlinked inode list.  If we
+ * don't find the inode in cache, then let the caller handle the situation.
+ */
+static struct xfs_inode *
+xfs_iunlink_lookup(
+	struct xfs_perag	*pag,
+	xfs_agino_t		agino)
+{
+	struct xfs_inode	*ip;
+
+	rcu_read_lock();
+	ip = radix_tree_lookup(&pag->pag_ici_root, agino);
+
+	/*
+	 * Inode not in memory or in RCU freeing limbo should not happen.
+	 * Warn about this and let the caller handle the failure.
+	 */
+	if (WARN_ON_ONCE(!ip || !ip->i_ino)) {
+		rcu_read_unlock();
+		return NULL;
+	}
+	ASSERT(!xfs_iflags_test(ip, XFS_IRECLAIMABLE | XFS_IRECLAIM));
+	rcu_read_unlock();
+	return ip;
+}
+
+/* Update the prev pointer of the next agino. */
+static int
+xfs_iunlink_update_backref(
+	struct xfs_perag	*pag,
+	xfs_agino_t		prev_agino,
+	xfs_agino_t		next_agino)
+{
+	struct xfs_inode	*ip;
+
+	/* No update necessary if we are at the end of the list. */
+	if (next_agino == NULLAGINO)
+		return 0;
+
+	ip = xfs_iunlink_lookup(pag, next_agino);
+	if (!ip)
+		return -EFSCORRUPTED;
+	ip->i_prev_unlinked = prev_agino;
+	return 0;
+}
+
+/*
+ * Point the AGI unlinked bucket at an inode and log the results.  The caller
+ * is responsible for validating the old value.
+ */
+STATIC int
+xfs_iunlink_update_bucket(
+	struct xfs_trans	*tp,
+	struct xfs_perag	*pag,
+	struct xfs_buf		*agibp,
+	unsigned int		bucket_index,
+	xfs_agino_t		new_agino)
+{
+	struct xfs_agi		*agi = agibp->b_addr;
+	xfs_agino_t		old_value;
+	int			offset;
+
+	ASSERT(xfs_verify_agino_or_null(pag, new_agino));
+
+	old_value = be32_to_cpu(agi->agi_unlinked[bucket_index]);
+	trace_xfs_iunlink_update_bucket(tp->t_mountp, pag->pag_agno, bucket_index,
+			old_value, new_agino);
+
+	/*
+	 * We should never find the head of the list already set to the value
+	 * passed in because either we're adding or removing ourselves from the
+	 * head of the list.
+	 */
+	if (old_value == new_agino) {
+		xfs_buf_mark_corrupt(agibp);
+		return -EFSCORRUPTED;
+	}
+
+	agi->agi_unlinked[bucket_index] = cpu_to_be32(new_agino);
+	offset = offsetof(struct xfs_agi, agi_unlinked) +
+			(sizeof(xfs_agino_t) * bucket_index);
+	xfs_trans_log_buf(tp, agibp, offset, offset + sizeof(xfs_agino_t) - 1);
+	return 0;
+}
+
+static int
+xfs_iunlink_insert_inode(
+	struct xfs_trans	*tp,
+	struct xfs_perag	*pag,
+	struct xfs_buf		*agibp,
+	struct xfs_inode	*ip)
+{
+	struct xfs_mount	*mp = tp->t_mountp;
+	struct xfs_agi		*agi = agibp->b_addr;
+	xfs_agino_t		next_agino;
+	xfs_agino_t		agino = XFS_INO_TO_AGINO(mp, ip->i_ino);
+	short			bucket_index = agino % XFS_AGI_UNLINKED_BUCKETS;
+	int			error;
+
+	/*
+	 * Get the index into the agi hash table for the list this inode will
+	 * go on.  Make sure the pointer isn't garbage and that this inode
+	 * isn't already on the list.
+	 */
+	next_agino = be32_to_cpu(agi->agi_unlinked[bucket_index]);
+	if (next_agino == agino ||
+	    !xfs_verify_agino_or_null(pag, next_agino)) {
+		xfs_buf_mark_corrupt(agibp);
+		return -EFSCORRUPTED;
+	}
+
+	/*
+	 * Update the prev pointer in the next inode to point back to this
+	 * inode.
+	 */
+	error = xfs_iunlink_update_backref(pag, agino, next_agino);
+	if (error)
+		return error;
+
+	if (next_agino != NULLAGINO) {
+		/*
+		 * There is already another inode in the bucket, so point this
+		 * inode to the current head of the list.
+		 */
+		error = xfs_iunlink_log_inode(tp, ip, pag, next_agino);
+		if (error)
+			return error;
+		ip->i_next_unlinked = next_agino;
+	}
+
+	/* Point the head of the list to point to this inode. */
+	return xfs_iunlink_update_bucket(tp, pag, agibp, bucket_index, agino);
+}
+
+/*
+ * This is called when the inode's link count has gone to 0 or we are creating
+ * a tmpfile via O_TMPFILE.  The inode @ip must have nlink == 0.
+ *
+ * We place the on-disk inode on a list in the AGI.  It will be pulled from this
+ * list when the inode is freed.
+ */
+STATIC int
+xfs_iunlink(
+	struct xfs_trans	*tp,
+	struct xfs_inode	*ip)
+{
+	struct xfs_mount	*mp = tp->t_mountp;
+	struct xfs_perag	*pag;
+	struct xfs_buf		*agibp;
+	int			error;
+
+	ASSERT(VFS_I(ip)->i_nlink == 0);
+	ASSERT(VFS_I(ip)->i_mode != 0);
+	trace_xfs_iunlink(ip);
+
+	pag = xfs_perag_get(mp, XFS_INO_TO_AGNO(mp, ip->i_ino));
+
+	/* Get the agi buffer first.  It ensures lock ordering on the list. */
+	error = xfs_read_agi(pag, tp, &agibp);
+	if (error)
+		goto out;
+
+	error = xfs_iunlink_insert_inode(tp, pag, agibp, ip);
+out:
+	xfs_perag_put(pag);
+	return error;
+}
+
+static int
+xfs_iunlink_remove_inode(
+	struct xfs_trans	*tp,
+	struct xfs_perag	*pag,
+	struct xfs_buf		*agibp,
+	struct xfs_inode	*ip)
+{
+	struct xfs_mount	*mp = tp->t_mountp;
+	struct xfs_agi		*agi = agibp->b_addr;
+	xfs_agino_t		agino = XFS_INO_TO_AGINO(mp, ip->i_ino);
+	xfs_agino_t		head_agino;
+	short			bucket_index = agino % XFS_AGI_UNLINKED_BUCKETS;
+	int			error;
+
+	trace_xfs_iunlink_remove(ip);
+
+	/*
+	 * Get the index into the agi hash table for the list this inode will
+	 * go on.  Make sure the head pointer isn't garbage.
+	 */
+	head_agino = be32_to_cpu(agi->agi_unlinked[bucket_index]);
+	if (!xfs_verify_agino(pag, head_agino)) {
+		XFS_CORRUPTION_ERROR(__func__, XFS_ERRLEVEL_LOW, mp,
+				agi, sizeof(*agi));
+		return -EFSCORRUPTED;
+	}
+
+	/*
+	 * Set our inode's next_unlinked pointer to NULL and then return
+	 * the old pointer value so that we can update whatever was previous
+	 * to us in the list to point to whatever was next in the list.
+	 */
+	error = xfs_iunlink_log_inode(tp, ip, pag, NULLAGINO);
+	if (error)
+		return error;
+
+	/*
+	 * Update the prev pointer in the next inode to point back to previous
+	 * inode in the chain.
+	 */
+	error = xfs_iunlink_update_backref(pag, ip->i_prev_unlinked,
+			ip->i_next_unlinked);
+	if (error)
+		return error;
+
+	if (head_agino != agino) {
+		struct xfs_inode	*prev_ip;
+
+		prev_ip = xfs_iunlink_lookup(pag, ip->i_prev_unlinked);
+		if (!prev_ip)
+			return -EFSCORRUPTED;
+
+		error = xfs_iunlink_log_inode(tp, prev_ip, pag,
+				ip->i_next_unlinked);
+		prev_ip->i_next_unlinked = ip->i_next_unlinked;
+	} else {
+		/* Point the head of the list to the next unlinked inode. */
+		error = xfs_iunlink_update_bucket(tp, pag, agibp, bucket_index,
+				ip->i_next_unlinked);
+	}
+
+	ip->i_next_unlinked = NULLAGINO;
+	ip->i_prev_unlinked = NULLAGINO;
+	return error;
+}
+
+/*
+ * Pull the on-disk inode from the AGI unlinked list.
+ */
+STATIC int
+xfs_iunlink_remove(
+	struct xfs_trans	*tp,
+	struct xfs_perag	*pag,
+	struct xfs_inode	*ip)
+{
+	struct xfs_buf		*agibp;
+	int			error;
+
+	trace_xfs_iunlink_remove(ip);
+
+	/* Get the agi buffer first.  It ensures lock ordering on the list. */
+	error = xfs_read_agi(pag, tp, &agibp);
+	if (error)
+		return error;
+
+	return xfs_iunlink_remove_inode(tp, pag, agibp, ip);
+}
+
+/*
+ * Look up the inode number specified and if it is not already marked XFS_ISTALE
+ * mark it stale. We should only find clean inodes in this lookup that aren't
+ * already stale.
+ */
+static void
+xfs_ifree_mark_inode_stale(
+	struct xfs_perag	*pag,
+	struct xfs_inode	*free_ip,
+	xfs_ino_t		inum)
+{
+	struct xfs_mount	*mp = pag->pag_mount;
+	struct xfs_inode_log_item *iip;
+	struct xfs_inode	*ip;
+
+retry:
+	rcu_read_lock();
+	ip = radix_tree_lookup(&pag->pag_ici_root, XFS_INO_TO_AGINO(mp, inum));
+
+	/* Inode not in memory, nothing to do */
+	if (!ip) {
+		rcu_read_unlock();
+		return;
+	}
+
+	/*
+	 * because this is an RCU protected lookup, we could find a recently
+	 * freed or even reallocated inode during the lookup. We need to check
+	 * under the i_flags_lock for a valid inode here. Skip it if it is not
+	 * valid, the wrong inode or stale.
+	 */
+	spin_lock(&ip->i_flags_lock);
+	if (ip->i_ino != inum || __xfs_iflags_test(ip, XFS_ISTALE))
+		goto out_iflags_unlock;
+
+	/*
+	 * Don't try to lock/unlock the current inode, but we _cannot_ skip the
+	 * other inodes that we did not find in the list attached to the buffer
+	 * and are not already marked stale. If we can't lock it, back off and
+	 * retry.
+	 */
+	if (ip != free_ip) {
+		if (!xfs_ilock_nowait(ip, XFS_ILOCK_EXCL)) {
+			spin_unlock(&ip->i_flags_lock);
+			rcu_read_unlock();
+			delay(1);
+			goto retry;
+		}
+	}
+	ip->i_flags |= XFS_ISTALE;
+
+	/*
+	 * If the inode is flushing, it is already attached to the buffer.  All
+	 * we needed to do here is mark the inode stale so buffer IO completion
+	 * will remove it from the AIL.
+	 */
+	iip = ip->i_itemp;
+	if (__xfs_iflags_test(ip, XFS_IFLUSHING)) {
+		ASSERT(!list_empty(&iip->ili_item.li_bio_list));
+		ASSERT(iip->ili_last_fields);
+		goto out_iunlock;
+	}
+
+	/*
+	 * Inodes not attached to the buffer can be released immediately.
+	 * Everything else has to go through xfs_iflush_abort() on journal
+	 * commit as the flock synchronises removal of the inode from the
+	 * cluster buffer against inode reclaim.
+	 */
+	if (!iip || list_empty(&iip->ili_item.li_bio_list))
+		goto out_iunlock;
+
+	__xfs_iflags_set(ip, XFS_IFLUSHING);
+	spin_unlock(&ip->i_flags_lock);
+	rcu_read_unlock();
+
+	/* we have a dirty inode in memory that has not yet been flushed. */
+	spin_lock(&iip->ili_lock);
+	iip->ili_last_fields = iip->ili_fields;
+	iip->ili_fields = 0;
+	iip->ili_fsync_fields = 0;
+	spin_unlock(&iip->ili_lock);
+	ASSERT(iip->ili_last_fields);
+
+	if (ip != free_ip)
+		xfs_iunlock(ip, XFS_ILOCK_EXCL);
+	return;
+
+out_iunlock:
+	if (ip != free_ip)
+		xfs_iunlock(ip, XFS_ILOCK_EXCL);
+out_iflags_unlock:
+	spin_unlock(&ip->i_flags_lock);
+	rcu_read_unlock();
+}
+
+/*
+ * A big issue when freeing the inode cluster is that we _cannot_ skip any
+ * inodes that are in memory - they all must be marked stale and attached to
+ * the cluster buffer.
+ */
+static int
+xfs_ifree_cluster(
+	struct xfs_trans	*tp,
+	struct xfs_perag	*pag,
+	struct xfs_inode	*free_ip,
+	struct xfs_icluster	*xic)
+{
+	struct xfs_mount	*mp = free_ip->i_mount;
+	struct xfs_ino_geometry	*igeo = M_IGEO(mp);
+	struct xfs_buf		*bp;
+	xfs_daddr_t		blkno;
+	xfs_ino_t		inum = xic->first_ino;
+	int			nbufs;
+	int			i, j;
+	int			ioffset;
+	int			error;
+
+	nbufs = igeo->ialloc_blks / igeo->blocks_per_cluster;
+
+	for (j = 0; j < nbufs; j++, inum += igeo->inodes_per_cluster) {
+		/*
+		 * The allocation bitmap tells us which inodes of the chunk were
+		 * physically allocated. Skip the cluster if an inode falls into
+		 * a sparse region.
+		 */
+		ioffset = inum - xic->first_ino;
+		if ((xic->alloc & XFS_INOBT_MASK(ioffset)) == 0) {
+			ASSERT(ioffset % igeo->inodes_per_cluster == 0);
+			continue;
+		}
+
+		blkno = XFS_AGB_TO_DADDR(mp, XFS_INO_TO_AGNO(mp, inum),
+					 XFS_INO_TO_AGBNO(mp, inum));
+
+		/*
+		 * We obtain and lock the backing buffer first in the process
+		 * here to ensure dirty inodes attached to the buffer remain in
+		 * the flushing state while we mark them stale.
+		 *
+		 * If we scan the in-memory inodes first, then buffer IO can
+		 * complete before we get a lock on it, and hence we may fail
+		 * to mark all the active inodes on the buffer stale.
+		 */
+		error = xfs_trans_get_buf(tp, mp->m_ddev_targp, blkno,
+				mp->m_bsize * igeo->blocks_per_cluster,
+				XBF_UNMAPPED, &bp);
+		if (error)
+			return error;
+
+		/*
+		 * This buffer may not have been correctly initialised as we
+		 * didn't read it from disk. That's not important because we are
+		 * only using to mark the buffer as stale in the log, and to
+		 * attach stale cached inodes on it. That means it will never be
+		 * dispatched for IO. If it is, we want to know about it, and we
+		 * want it to fail. We can acheive this by adding a write
+		 * verifier to the buffer.
+		 */
+		bp->b_ops = &xfs_inode_buf_ops;
+
+		/*
+		 * Now we need to set all the cached clean inodes as XFS_ISTALE,
+		 * too. This requires lookups, and will skip inodes that we've
+		 * already marked XFS_ISTALE.
+		 */
+		for (i = 0; i < igeo->inodes_per_cluster; i++)
+			xfs_ifree_mark_inode_stale(pag, free_ip, inum + i);
+
+		xfs_trans_stale_inode_buf(tp, bp);
+		xfs_trans_binval(tp, bp);
+	}
+	return 0;
+}
+
+/*
+ * This is called to return an inode to the inode free list.  The inode should
+ * already be truncated to 0 length and have no pages associated with it.  This
+ * routine also assumes that the inode is already a part of the transaction.
+ *
+ * The on-disk copy of the inode will have been added to the list of unlinked
+ * inodes in the AGI. We need to remove the inode from that list atomically with
+ * respect to freeing it here.
+ */
+int
+xfs_ifree(
+	struct xfs_trans	*tp,
+	struct xfs_inode	*ip)
+{
+	struct xfs_mount	*mp = ip->i_mount;
+	struct xfs_perag	*pag;
+	struct xfs_icluster	xic = { 0 };
+	struct xfs_inode_log_item *iip = ip->i_itemp;
+	int			error;
+
+	ASSERT(xfs_isilocked(ip, XFS_ILOCK_EXCL));
+	ASSERT(VFS_I(ip)->i_nlink == 0);
+	ASSERT(ip->i_df.if_nextents == 0);
+	ASSERT(ip->i_disk_size == 0 || !S_ISREG(VFS_I(ip)->i_mode));
+	ASSERT(ip->i_nblocks == 0);
+
+	pag = xfs_perag_get(mp, XFS_INO_TO_AGNO(mp, ip->i_ino));
+
+	/*
+	 * Free the inode first so that we guarantee that the AGI lock is going
+	 * to be taken before we remove the inode from the unlinked list. This
+	 * makes the AGI lock -> unlinked list modification order the same as
+	 * used in O_TMPFILE creation.
+	 */
+	error = xfs_difree(tp, pag, ip->i_ino, &xic);
+	if (error)
+		goto out;
+
+	error = xfs_iunlink_remove(tp, pag, ip);
+	if (error)
+		goto out;
+
+	/*
+	 * Free any local-format data sitting around before we reset the
+	 * data fork to extents format.  Note that the attr fork data has
+	 * already been freed by xfs_attr_inactive.
+	 */
+	if (ip->i_df.if_format == XFS_DINODE_FMT_LOCAL) {
+		kmem_free(ip->i_df.if_u1.if_data);
+		ip->i_df.if_u1.if_data = NULL;
+		ip->i_df.if_bytes = 0;
+	}
+
+	VFS_I(ip)->i_mode = 0;		/* mark incore inode as free */
+	ip->i_diflags = 0;
+	ip->i_diflags2 = mp->m_ino_geo.new_diflags2;
+	ip->i_forkoff = 0;		/* mark the attr fork not in use */
+	ip->i_df.if_format = XFS_DINODE_FMT_EXTENTS;
+	if (xfs_iflags_test(ip, XFS_IPRESERVE_DM_FIELDS))
+		xfs_iflags_clear(ip, XFS_IPRESERVE_DM_FIELDS);
+
+	/* Don't attempt to replay owner changes for a deleted inode */
+	spin_lock(&iip->ili_lock);
+	iip->ili_fields &= ~(XFS_ILOG_AOWNER | XFS_ILOG_DOWNER);
+	spin_unlock(&iip->ili_lock);
+
+	/*
+	 * Bump the generation count so no one will be confused
+	 * by reincarnations of this inode.
+	 */
+	VFS_I(ip)->i_generation++;
+	xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
+
+	if (xic.deleted)
+		error = xfs_ifree_cluster(tp, pag, ip, &xic);
+out:
+	xfs_perag_put(pag);
+	return error;
+}
+
+/*
+ * This is called to unpin an inode.  The caller must have the inode locked
+ * in at least shared mode so that the buffer cannot be subsequently pinned
+ * once someone is waiting for it to be unpinned.
+ */
+static void
+xfs_iunpin(
+	struct xfs_inode	*ip)
+{
+	ASSERT(xfs_isilocked(ip, XFS_ILOCK_EXCL|XFS_ILOCK_SHARED));
+
+	trace_xfs_inode_unpin_nowait(ip, _RET_IP_);
+
+	/* Give the log a push to start the unpinning I/O */
+	xfs_log_force_seq(ip->i_mount, ip->i_itemp->ili_commit_seq, 0, NULL);
+
+}
+
+static void
+__xfs_iunpin_wait(
+	struct xfs_inode	*ip)
+{
+	wait_queue_head_t *wq = bit_waitqueue(&ip->i_flags, __XFS_IPINNED_BIT);
+	DEFINE_WAIT_BIT(wait, &ip->i_flags, __XFS_IPINNED_BIT);
+
+	xfs_iunpin(ip);
+
+	do {
+		prepare_to_wait(wq, &wait.wq_entry, TASK_UNINTERRUPTIBLE);
+		if (xfs_ipincount(ip))
+			io_schedule();
+	} while (xfs_ipincount(ip));
+	finish_wait(wq, &wait.wq_entry);
+}
+
+void
+xfs_iunpin_wait(
+	struct xfs_inode	*ip)
+{
+	if (xfs_ipincount(ip))
+		__xfs_iunpin_wait(ip);
+}
+
+/*
+ * Removing an inode from the namespace involves removing the directory entry
+ * and dropping the link count on the inode. Removing the directory entry can
+ * result in locking an AGF (directory blocks were freed) and removing a link
+ * count can result in placing the inode on an unlinked list which results in
+ * locking an AGI.
+ *
+ * The big problem here is that we have an ordering constraint on AGF and AGI
+ * locking - inode allocation locks the AGI, then can allocate a new extent for
+ * new inodes, locking the AGF after the AGI. Similarly, freeing the inode
+ * removes the inode from the unlinked list, requiring that we lock the AGI
+ * first, and then freeing the inode can result in an inode chunk being freed
+ * and hence freeing disk space requiring that we lock an AGF.
+ *
+ * Hence the ordering that is imposed by other parts of the code is AGI before
+ * AGF. This means we cannot remove the directory entry before we drop the inode
+ * reference count and put it on the unlinked list as this results in a lock
+ * order of AGF then AGI, and this can deadlock against inode allocation and
+ * freeing. Therefore we must drop the link counts before we remove the
+ * directory entry.
+ *
+ * This is still safe from a transactional point of view - it is not until we
+ * get to xfs_defer_finish() that we have the possibility of multiple
+ * transactions in this operation. Hence as long as we remove the directory
+ * entry and drop the link count in the first transaction of the remove
+ * operation, there are no transactional constraints on the ordering here.
+ */
+int
+xfs_remove(
+	xfs_inode_t             *dp,
+	struct xfs_name		*name,
+	xfs_inode_t		*ip)
+{
+	xfs_mount_t		*mp = dp->i_mount;
+	xfs_trans_t             *tp = NULL;
+	int			is_dir = S_ISDIR(VFS_I(ip)->i_mode);
+	int			dontcare;
+	int                     error = 0;
+	uint			resblks;
+
+	trace_xfs_remove(dp, name);
+
+	if (xfs_is_shutdown(mp))
+		return -EIO;
+
+	error = xfs_qm_dqattach(dp);
+	if (error)
+		goto std_return;
+
+	error = xfs_qm_dqattach(ip);
+	if (error)
+		goto std_return;
+
+	/*
+	 * We try to get the real space reservation first, allowing for
+	 * directory btree deletion(s) implying possible bmap insert(s).  If we
+	 * can't get the space reservation then we use 0 instead, and avoid the
+	 * bmap btree insert(s) in the directory code by, if the bmap insert
+	 * tries to happen, instead trimming the LAST block from the directory.
+	 *
+	 * Ignore EDQUOT and ENOSPC being returned via nospace_error because
+	 * the directory code can handle a reservationless update and we don't
+	 * want to prevent a user from trying to free space by deleting things.
+	 */
+	resblks = XFS_REMOVE_SPACE_RES(mp);
+	error = xfs_trans_alloc_dir(dp, &M_RES(mp)->tr_remove, ip, &resblks,
+			&tp, &dontcare);
+	if (error) {
+		ASSERT(error != -ENOSPC);
+		goto std_return;
+	}
+
+	/*
+	 * If we're removing a directory perform some additional validation.
+	 */
+	if (is_dir) {
+		ASSERT(VFS_I(ip)->i_nlink >= 2);
+		if (VFS_I(ip)->i_nlink != 2) {
+			error = -ENOTEMPTY;
+			goto out_trans_cancel;
+		}
+		if (!xfs_dir_isempty(ip)) {
+			error = -ENOTEMPTY;
+			goto out_trans_cancel;
+		}
+
+		/* Drop the link from ip's "..".  */
+		error = xfs_droplink(tp, dp);
+		if (error)
+			goto out_trans_cancel;
+
+		/* Drop the "." link from ip to self.  */
+		error = xfs_droplink(tp, ip);
+		if (error)
+			goto out_trans_cancel;
+
+		/*
+		 * Point the unlinked child directory's ".." entry to the root
+		 * directory to eliminate back-references to inodes that may
+		 * get freed before the child directory is closed.  If the fs
+		 * gets shrunk, this can lead to dirent inode validation errors.
+		 */
+		if (dp->i_ino != tp->t_mountp->m_sb.sb_rootino) {
+			error = xfs_dir_replace(tp, ip, &xfs_name_dotdot,
+					tp->t_mountp->m_sb.sb_rootino, 0);
+			if (error)
+				return error;
+		}
+	} else {
+		/*
+		 * When removing a non-directory we need to log the parent
+		 * inode here.  For a directory this is done implicitly
+		 * by the xfs_droplink call for the ".." entry.
+		 */
+		xfs_trans_log_inode(tp, dp, XFS_ILOG_CORE);
+	}
+	xfs_trans_ichgtime(tp, dp, XFS_ICHGTIME_MOD | XFS_ICHGTIME_CHG);
+
+	/* Drop the link from dp to ip. */
+	error = xfs_droplink(tp, ip);
+	if (error)
+		goto out_trans_cancel;
+
+	error = xfs_dir_removename(tp, dp, name, ip->i_ino, resblks);
+	if (error) {
+		ASSERT(error != -ENOENT);
+		goto out_trans_cancel;
+	}
+
+	/*
+	 * If this is a synchronous mount, make sure that the
+	 * remove transaction goes to disk before returning to
+	 * the user.
+	 */
+	if (xfs_has_wsync(mp) || xfs_has_dirsync(mp))
+		xfs_trans_set_sync(tp);
+
+	error = xfs_trans_commit(tp);
+	if (error)
+		goto std_return;
+
+	if (is_dir && xfs_inode_is_filestream(ip))
+		xfs_filestream_deassociate(ip);
+
+	return 0;
+
+ out_trans_cancel:
+	xfs_trans_cancel(tp);
+ std_return:
+	return error;
+}
+
+/*
+ * Enter all inodes for a rename transaction into a sorted array.
+ */
+#define __XFS_SORT_INODES	5
+STATIC void
+xfs_sort_for_rename(
+	struct xfs_inode	*dp1,	/* in: old (source) directory inode */
+	struct xfs_inode	*dp2,	/* in: new (target) directory inode */
+	struct xfs_inode	*ip1,	/* in: inode of old entry */
+	struct xfs_inode	*ip2,	/* in: inode of new entry */
+	struct xfs_inode	*wip,	/* in: whiteout inode */
+	struct xfs_inode	**i_tab,/* out: sorted array of inodes */
+	int			*num_inodes)  /* in/out: inodes in array */
+{
+	int			i, j;
+
+	ASSERT(*num_inodes == __XFS_SORT_INODES);
+	memset(i_tab, 0, *num_inodes * sizeof(struct xfs_inode *));
+
+	/*
+	 * i_tab contains a list of pointers to inodes.  We initialize
+	 * the table here & we'll sort it.  We will then use it to
+	 * order the acquisition of the inode locks.
+	 *
+	 * Note that the table may contain duplicates.  e.g., dp1 == dp2.
+	 */
+	i = 0;
+	i_tab[i++] = dp1;
+	i_tab[i++] = dp2;
+	i_tab[i++] = ip1;
+	if (ip2)
+		i_tab[i++] = ip2;
+	if (wip)
+		i_tab[i++] = wip;
+	*num_inodes = i;
+
+	/*
+	 * Sort the elements via bubble sort.  (Remember, there are at
+	 * most 5 elements to sort, so this is adequate.)
+	 */
+	for (i = 0; i < *num_inodes; i++) {
+		for (j = 1; j < *num_inodes; j++) {
+			if (i_tab[j]->i_ino < i_tab[j-1]->i_ino) {
+				struct xfs_inode *temp = i_tab[j];
+				i_tab[j] = i_tab[j-1];
+				i_tab[j-1] = temp;
+			}
+		}
+	}
+}
+
+static int
+xfs_finish_rename(
+	struct xfs_trans	*tp)
+{
+	/*
+	 * If this is a synchronous mount, make sure that the rename transaction
+	 * goes to disk before returning to the user.
+	 */
+	if (xfs_has_wsync(tp->t_mountp) || xfs_has_dirsync(tp->t_mountp))
+		xfs_trans_set_sync(tp);
+
+	return xfs_trans_commit(tp);
+}
+
+/*
+ * xfs_cross_rename()
+ *
+ * responsible for handling RENAME_EXCHANGE flag in renameat2() syscall
+ */
+STATIC int
+xfs_cross_rename(
+	struct xfs_trans	*tp,
+	struct xfs_inode	*dp1,
+	struct xfs_name		*name1,
+	struct xfs_inode	*ip1,
+	struct xfs_inode	*dp2,
+	struct xfs_name		*name2,
+	struct xfs_inode	*ip2,
+	int			spaceres)
+{
+	int		error = 0;
+	int		ip1_flags = 0;
+	int		ip2_flags = 0;
+	int		dp2_flags = 0;
+
+	/* Swap inode number for dirent in first parent */
+	error = xfs_dir_replace(tp, dp1, name1, ip2->i_ino, spaceres);
+	if (error)
+		goto out_trans_abort;
+
+	/* Swap inode number for dirent in second parent */
+	error = xfs_dir_replace(tp, dp2, name2, ip1->i_ino, spaceres);
+	if (error)
+		goto out_trans_abort;
+
+	/*
+	 * If we're renaming one or more directories across different parents,
+	 * update the respective ".." entries (and link counts) to match the new
+	 * parents.
+	 */
+	if (dp1 != dp2) {
+		dp2_flags = XFS_ICHGTIME_MOD | XFS_ICHGTIME_CHG;
+
+		if (S_ISDIR(VFS_I(ip2)->i_mode)) {
+			error = xfs_dir_replace(tp, ip2, &xfs_name_dotdot,
+						dp1->i_ino, spaceres);
+			if (error)
+				goto out_trans_abort;
+
+			/* transfer ip2 ".." reference to dp1 */
+			if (!S_ISDIR(VFS_I(ip1)->i_mode)) {
+				error = xfs_droplink(tp, dp2);
+				if (error)
+					goto out_trans_abort;
+				xfs_bumplink(tp, dp1);
+			}
+
+			/*
+			 * Although ip1 isn't changed here, userspace needs
+			 * to be warned about the change, so that applications
+			 * relying on it (like backup ones), will properly
+			 * notify the change
+			 */
+			ip1_flags |= XFS_ICHGTIME_CHG;
+			ip2_flags |= XFS_ICHGTIME_MOD | XFS_ICHGTIME_CHG;
+		}
+
+		if (S_ISDIR(VFS_I(ip1)->i_mode)) {
+			error = xfs_dir_replace(tp, ip1, &xfs_name_dotdot,
+						dp2->i_ino, spaceres);
+			if (error)
+				goto out_trans_abort;
+
+			/* transfer ip1 ".." reference to dp2 */
+			if (!S_ISDIR(VFS_I(ip2)->i_mode)) {
+				error = xfs_droplink(tp, dp1);
+				if (error)
+					goto out_trans_abort;
+				xfs_bumplink(tp, dp2);
+			}
+
+			/*
+			 * Although ip2 isn't changed here, userspace needs
+			 * to be warned about the change, so that applications
+			 * relying on it (like backup ones), will properly
+			 * notify the change
+			 */
+			ip1_flags |= XFS_ICHGTIME_MOD | XFS_ICHGTIME_CHG;
+			ip2_flags |= XFS_ICHGTIME_CHG;
+		}
+	}
+
+	if (ip1_flags) {
+		xfs_trans_ichgtime(tp, ip1, ip1_flags);
+		xfs_trans_log_inode(tp, ip1, XFS_ILOG_CORE);
+	}
+	if (ip2_flags) {
+		xfs_trans_ichgtime(tp, ip2, ip2_flags);
+		xfs_trans_log_inode(tp, ip2, XFS_ILOG_CORE);
+	}
+	if (dp2_flags) {
+		xfs_trans_ichgtime(tp, dp2, dp2_flags);
+		xfs_trans_log_inode(tp, dp2, XFS_ILOG_CORE);
+	}
+	xfs_trans_ichgtime(tp, dp1, XFS_ICHGTIME_MOD | XFS_ICHGTIME_CHG);
+	xfs_trans_log_inode(tp, dp1, XFS_ILOG_CORE);
+	return xfs_finish_rename(tp);
+
+out_trans_abort:
+	xfs_trans_cancel(tp);
+	return error;
+}
+
+/*
+ * xfs_rename_alloc_whiteout()
+ *
+ * Return a referenced, unlinked, unlocked inode that can be used as a
+ * whiteout in a rename transaction. We use a tmpfile inode here so that if we
+ * crash between allocating the inode and linking it into the rename transaction
+ * recovery will free the inode and we won't leak it.
+ */
+static int
+xfs_rename_alloc_whiteout(
+	struct user_namespace	*mnt_userns,
+	struct xfs_name		*src_name,
+	struct xfs_inode	*dp,
+	struct xfs_inode	**wip)
+{
+	struct xfs_inode	*tmpfile;
+	struct qstr		name;
+	int			error;
+
+	error = xfs_create_tmpfile(mnt_userns, dp, S_IFCHR | WHITEOUT_MODE,
+				   &tmpfile);
+	if (error)
+		return error;
+
+	name.name = src_name->name;
+	name.len = src_name->len;
+	error = xfs_inode_init_security(VFS_I(tmpfile), VFS_I(dp), &name);
+	if (error) {
+		xfs_finish_inode_setup(tmpfile);
+		xfs_irele(tmpfile);
+		return error;
+	}
+
+	/*
+	 * Prepare the tmpfile inode as if it were created through the VFS.
+	 * Complete the inode setup and flag it as linkable.  nlink is already
+	 * zero, so we can skip the drop_nlink.
+	 */
+	xfs_setup_iops(tmpfile);
+	xfs_finish_inode_setup(tmpfile);
+	VFS_I(tmpfile)->i_state |= I_LINKABLE;
+
+	*wip = tmpfile;
+	return 0;
+}
+
+/*
+ * xfs_rename
+ */
+int
+xfs_rename(
+	struct user_namespace	*mnt_userns,
+	struct xfs_inode	*src_dp,
+	struct xfs_name		*src_name,
+	struct xfs_inode	*src_ip,
+	struct xfs_inode	*target_dp,
+	struct xfs_name		*target_name,
+	struct xfs_inode	*target_ip,
+	unsigned int		flags)
+{
+	struct xfs_mount	*mp = src_dp->i_mount;
+	struct xfs_trans	*tp;
+	struct xfs_inode	*wip = NULL;		/* whiteout inode */
+	struct xfs_inode	*inodes[__XFS_SORT_INODES];
+	int			i;
+	int			num_inodes = __XFS_SORT_INODES;
+	bool			new_parent = (src_dp != target_dp);
+	bool			src_is_directory = S_ISDIR(VFS_I(src_ip)->i_mode);
+	int			spaceres;
+	bool			retried = false;
+	int			error, nospace_error = 0;
+
+	trace_xfs_rename(src_dp, target_dp, src_name, target_name);
+
+	if ((flags & RENAME_EXCHANGE) && !target_ip)
+		return -EINVAL;
+
+	/*
+	 * If we are doing a whiteout operation, allocate the whiteout inode
+	 * we will be placing at the target and ensure the type is set
+	 * appropriately.
+	 */
+	if (flags & RENAME_WHITEOUT) {
+		error = xfs_rename_alloc_whiteout(mnt_userns, src_name,
+						  target_dp, &wip);
+		if (error)
+			return error;
+
+		/* setup target dirent info as whiteout */
+		src_name->type = XFS_DIR3_FT_CHRDEV;
+	}
+
+	xfs_sort_for_rename(src_dp, target_dp, src_ip, target_ip, wip,
+				inodes, &num_inodes);
+
+retry:
+	nospace_error = 0;
+	spaceres = XFS_RENAME_SPACE_RES(mp, target_name->len);
+	error = xfs_trans_alloc(mp, &M_RES(mp)->tr_rename, spaceres, 0, 0, &tp);
+	if (error == -ENOSPC) {
+		nospace_error = error;
+		spaceres = 0;
+		error = xfs_trans_alloc(mp, &M_RES(mp)->tr_rename, 0, 0, 0,
+				&tp);
+	}
+	if (error)
+		goto out_release_wip;
+
+	/*
+	 * Attach the dquots to the inodes
+	 */
+	error = xfs_qm_vop_rename_dqattach(inodes);
+	if (error)
+		goto out_trans_cancel;
+
+	/*
+	 * Lock all the participating inodes. Depending upon whether
+	 * the target_name exists in the target directory, and
+	 * whether the target directory is the same as the source
+	 * directory, we can lock from 2 to 5 inodes.
+	 */
+	xfs_lock_inodes(inodes, num_inodes, XFS_ILOCK_EXCL);
+
+	/*
+	 * Join all the inodes to the transaction. From this point on,
+	 * we can rely on either trans_commit or trans_cancel to unlock
+	 * them.
+	 */
+	xfs_trans_ijoin(tp, src_dp, XFS_ILOCK_EXCL);
+	if (new_parent)
+		xfs_trans_ijoin(tp, target_dp, XFS_ILOCK_EXCL);
+	xfs_trans_ijoin(tp, src_ip, XFS_ILOCK_EXCL);
+	if (target_ip)
+		xfs_trans_ijoin(tp, target_ip, XFS_ILOCK_EXCL);
+	if (wip)
+		xfs_trans_ijoin(tp, wip, XFS_ILOCK_EXCL);
+
+	/*
+	 * If we are using project inheritance, we only allow renames
+	 * into our tree when the project IDs are the same; else the
+	 * tree quota mechanism would be circumvented.
+	 */
+	if (unlikely((target_dp->i_diflags & XFS_DIFLAG_PROJINHERIT) &&
+		     target_dp->i_projid != src_ip->i_projid)) {
+		error = -EXDEV;
+		goto out_trans_cancel;
+	}
+
+	/* RENAME_EXCHANGE is unique from here on. */
+	if (flags & RENAME_EXCHANGE)
+		return xfs_cross_rename(tp, src_dp, src_name, src_ip,
+					target_dp, target_name, target_ip,
+					spaceres);
+
+	/*
+	 * Try to reserve quota to handle an expansion of the target directory.
+	 * We'll allow the rename to continue in reservationless mode if we hit
+	 * a space usage constraint.  If we trigger reservationless mode, save
+	 * the errno if there isn't any free space in the target directory.
+	 */
+	if (spaceres != 0) {
+		error = xfs_trans_reserve_quota_nblks(tp, target_dp, spaceres,
+				0, false);
+		if (error == -EDQUOT || error == -ENOSPC) {
+			if (!retried) {
+				xfs_trans_cancel(tp);
+				xfs_blockgc_free_quota(target_dp, 0);
+				retried = true;
+				goto retry;
+			}
+
+			nospace_error = error;
+			spaceres = 0;
+			error = 0;
+		}
+		if (error)
+			goto out_trans_cancel;
+	}
+
+	/*
+	 * Check for expected errors before we dirty the transaction
+	 * so we can return an error without a transaction abort.
+	 */
+	if (target_ip == NULL) {
+		/*
+		 * If there's no space reservation, check the entry will
+		 * fit before actually inserting it.
+		 */
+		if (!spaceres) {
+			error = xfs_dir_canenter(tp, target_dp, target_name);
+			if (error)
+				goto out_trans_cancel;
+		}
+	} else {
+		/*
+		 * If target exists and it's a directory, check that whether
+		 * it can be destroyed.
+		 */
+		if (S_ISDIR(VFS_I(target_ip)->i_mode) &&
+		    (!xfs_dir_isempty(target_ip) ||
+		     (VFS_I(target_ip)->i_nlink > 2))) {
+			error = -EEXIST;
+			goto out_trans_cancel;
+		}
+	}
+
+	/*
+	 * Lock the AGI buffers we need to handle bumping the nlink of the
+	 * whiteout inode off the unlinked list and to handle dropping the
+	 * nlink of the target inode.  Per locking order rules, do this in
+	 * increasing AG order and before directory block allocation tries to
+	 * grab AGFs because we grab AGIs before AGFs.
+	 *
+	 * The (vfs) caller must ensure that if src is a directory then
+	 * target_ip is either null or an empty directory.
+	 */
+	for (i = 0; i < num_inodes && inodes[i] != NULL; i++) {
+		if (inodes[i] == wip ||
+		    (inodes[i] == target_ip &&
+		     (VFS_I(target_ip)->i_nlink == 1 || src_is_directory))) {
+			struct xfs_perag	*pag;
+			struct xfs_buf		*bp;
+
+			pag = xfs_perag_get(mp,
+					XFS_INO_TO_AGNO(mp, inodes[i]->i_ino));
+			error = xfs_read_agi(pag, tp, &bp);
+			xfs_perag_put(pag);
+			if (error)
+				goto out_trans_cancel;
+		}
+	}
+
+	/*
+	 * Directory entry creation below may acquire the AGF. Remove
+	 * the whiteout from the unlinked list first to preserve correct
+	 * AGI/AGF locking order. This dirties the transaction so failures
+	 * after this point will abort and log recovery will clean up the
+	 * mess.
+	 *
+	 * For whiteouts, we need to bump the link count on the whiteout
+	 * inode. After this point, we have a real link, clear the tmpfile
+	 * state flag from the inode so it doesn't accidentally get misused
+	 * in future.
+	 */
+	if (wip) {
+		struct xfs_perag	*pag;
+
+		ASSERT(VFS_I(wip)->i_nlink == 0);
+
+		pag = xfs_perag_get(mp, XFS_INO_TO_AGNO(mp, wip->i_ino));
+		error = xfs_iunlink_remove(tp, pag, wip);
+		xfs_perag_put(pag);
+		if (error)
+			goto out_trans_cancel;
+
+		xfs_bumplink(tp, wip);
+		VFS_I(wip)->i_state &= ~I_LINKABLE;
+	}
+
+	/*
+	 * Set up the target.
+	 */
+	if (target_ip == NULL) {
+		/*
+		 * If target does not exist and the rename crosses
+		 * directories, adjust the target directory link count
+		 * to account for the ".." reference from the new entry.
+		 */
+		error = xfs_dir_createname(tp, target_dp, target_name,
+					   src_ip->i_ino, spaceres);
+		if (error)
+			goto out_trans_cancel;
+
+		xfs_trans_ichgtime(tp, target_dp,
+					XFS_ICHGTIME_MOD | XFS_ICHGTIME_CHG);
+
+		if (new_parent && src_is_directory) {
+			xfs_bumplink(tp, target_dp);
+		}
+	} else { /* target_ip != NULL */
+		/*
+		 * Link the source inode under the target name.
+		 * If the source inode is a directory and we are moving
+		 * it across directories, its ".." entry will be
+		 * inconsistent until we replace that down below.
+		 *
+		 * In case there is already an entry with the same
+		 * name at the destination directory, remove it first.
+		 */
+		error = xfs_dir_replace(tp, target_dp, target_name,
+					src_ip->i_ino, spaceres);
+		if (error)
+			goto out_trans_cancel;
+
+		xfs_trans_ichgtime(tp, target_dp,
+					XFS_ICHGTIME_MOD | XFS_ICHGTIME_CHG);
+
+		/*
+		 * Decrement the link count on the target since the target
+		 * dir no longer points to it.
+		 */
+		error = xfs_droplink(tp, target_ip);
+		if (error)
+			goto out_trans_cancel;
+
+		if (src_is_directory) {
+			/*
+			 * Drop the link from the old "." entry.
+			 */
+			error = xfs_droplink(tp, target_ip);
+			if (error)
+				goto out_trans_cancel;
+		}
+	} /* target_ip != NULL */
+
+	/*
+	 * Remove the source.
+	 */
+	if (new_parent && src_is_directory) {
+		/*
+		 * Rewrite the ".." entry to point to the new
+		 * directory.
+		 */
+		error = xfs_dir_replace(tp, src_ip, &xfs_name_dotdot,
+					target_dp->i_ino, spaceres);
+		ASSERT(error != -EEXIST);
+		if (error)
+			goto out_trans_cancel;
+	}
+
+	/*
+	 * We always want to hit the ctime on the source inode.
+	 *
+	 * This isn't strictly required by the standards since the source
+	 * inode isn't really being changed, but old unix file systems did
+	 * it and some incremental backup programs won't work without it.
+	 */
+	xfs_trans_ichgtime(tp, src_ip, XFS_ICHGTIME_CHG);
+	xfs_trans_log_inode(tp, src_ip, XFS_ILOG_CORE);
+
+	/*
+	 * Adjust the link count on src_dp.  This is necessary when
+	 * renaming a directory, either within one parent when
+	 * the target existed, or across two parent directories.
+	 */
+	if (src_is_directory && (new_parent || target_ip != NULL)) {
+
+		/*
+		 * Decrement link count on src_directory since the
+		 * entry that's moved no longer points to it.
+		 */
+		error = xfs_droplink(tp, src_dp);
+		if (error)
+			goto out_trans_cancel;
+	}
+
+	/*
+	 * For whiteouts, we only need to update the source dirent with the
+	 * inode number of the whiteout inode rather than removing it
+	 * altogether.
+	 */
+	if (wip)
+		error = xfs_dir_replace(tp, src_dp, src_name, wip->i_ino,
+					spaceres);
+	else
+		error = xfs_dir_removename(tp, src_dp, src_name, src_ip->i_ino,
+					   spaceres);
+
+	if (error)
+		goto out_trans_cancel;
+
+	xfs_trans_ichgtime(tp, src_dp, XFS_ICHGTIME_MOD | XFS_ICHGTIME_CHG);
+	xfs_trans_log_inode(tp, src_dp, XFS_ILOG_CORE);
+	if (new_parent)
+		xfs_trans_log_inode(tp, target_dp, XFS_ILOG_CORE);
+
+	error = xfs_finish_rename(tp);
+	if (wip)
+		xfs_irele(wip);
+	return error;
+
+out_trans_cancel:
+	xfs_trans_cancel(tp);
+out_release_wip:
+	if (wip)
+		xfs_irele(wip);
+	if (error == -ENOSPC && nospace_error)
+		error = nospace_error;
+	return error;
+}
+
+static int
+xfs_iflush(
+	struct xfs_inode	*ip,
+	struct xfs_buf		*bp)
+{
+	struct xfs_inode_log_item *iip = ip->i_itemp;
+	struct xfs_dinode	*dip;
+	struct xfs_mount	*mp = ip->i_mount;
+	int			error;
+
+	ASSERT(xfs_isilocked(ip, XFS_ILOCK_EXCL|XFS_ILOCK_SHARED));
+	ASSERT(xfs_iflags_test(ip, XFS_IFLUSHING));
+	ASSERT(ip->i_df.if_format != XFS_DINODE_FMT_BTREE ||
+	       ip->i_df.if_nextents > XFS_IFORK_MAXEXT(ip, XFS_DATA_FORK));
+	ASSERT(iip->ili_item.li_buf == bp);
+
+	dip = xfs_buf_offset(bp, ip->i_imap.im_boffset);
+
+	/*
+	 * We don't flush the inode if any of the following checks fail, but we
+	 * do still update the log item and attach to the backing buffer as if
+	 * the flush happened. This is a formality to facilitate predictable
+	 * error handling as the caller will shutdown and fail the buffer.
+	 */
+	error = -EFSCORRUPTED;
+	if (XFS_TEST_ERROR(dip->di_magic != cpu_to_be16(XFS_DINODE_MAGIC),
+			       mp, XFS_ERRTAG_IFLUSH_1)) {
+		xfs_alert_tag(mp, XFS_PTAG_IFLUSH,
+			"%s: Bad inode %llu magic number 0x%x, ptr "PTR_FMT,
+			__func__, ip->i_ino, be16_to_cpu(dip->di_magic), dip);
+		goto flush_out;
+	}
+	if (S_ISREG(VFS_I(ip)->i_mode)) {
+		if (XFS_TEST_ERROR(
+		    ip->i_df.if_format != XFS_DINODE_FMT_EXTENTS &&
+		    ip->i_df.if_format != XFS_DINODE_FMT_BTREE,
+		    mp, XFS_ERRTAG_IFLUSH_3)) {
+			xfs_alert_tag(mp, XFS_PTAG_IFLUSH,
+				"%s: Bad regular inode %llu, ptr "PTR_FMT,
+				__func__, ip->i_ino, ip);
+			goto flush_out;
+		}
+	} else if (S_ISDIR(VFS_I(ip)->i_mode)) {
+		if (XFS_TEST_ERROR(
+		    ip->i_df.if_format != XFS_DINODE_FMT_EXTENTS &&
+		    ip->i_df.if_format != XFS_DINODE_FMT_BTREE &&
+		    ip->i_df.if_format != XFS_DINODE_FMT_LOCAL,
+		    mp, XFS_ERRTAG_IFLUSH_4)) {
+			xfs_alert_tag(mp, XFS_PTAG_IFLUSH,
+				"%s: Bad directory inode %llu, ptr "PTR_FMT,
+				__func__, ip->i_ino, ip);
+			goto flush_out;
+		}
+	}
+	if (XFS_TEST_ERROR(ip->i_df.if_nextents + xfs_ifork_nextents(&ip->i_af) >
+				ip->i_nblocks, mp, XFS_ERRTAG_IFLUSH_5)) {
+		xfs_alert_tag(mp, XFS_PTAG_IFLUSH,
+			"%s: detected corrupt incore inode %llu, "
+			"total extents = %llu nblocks = %lld, ptr "PTR_FMT,
+			__func__, ip->i_ino,
+			ip->i_df.if_nextents + xfs_ifork_nextents(&ip->i_af),
+			ip->i_nblocks, ip);
+		goto flush_out;
+	}
+	if (XFS_TEST_ERROR(ip->i_forkoff > mp->m_sb.sb_inodesize,
+				mp, XFS_ERRTAG_IFLUSH_6)) {
+		xfs_alert_tag(mp, XFS_PTAG_IFLUSH,
+			"%s: bad inode %llu, forkoff 0x%x, ptr "PTR_FMT,
+			__func__, ip->i_ino, ip->i_forkoff, ip);
+		goto flush_out;
+	}
+
+	/*
+	 * Inode item log recovery for v2 inodes are dependent on the flushiter
+	 * count for correct sequencing.  We bump the flush iteration count so
+	 * we can detect flushes which postdate a log record during recovery.
+	 * This is redundant as we now log every change and hence this can't
+	 * happen but we need to still do it to ensure backwards compatibility
+	 * with old kernels that predate logging all inode changes.
+	 */
+	if (!xfs_has_v3inodes(mp))
+		ip->i_flushiter++;
+
+	/*
+	 * If there are inline format data / attr forks attached to this inode,
+	 * make sure they are not corrupt.
+	 */
+	if (ip->i_df.if_format == XFS_DINODE_FMT_LOCAL &&
+	    xfs_ifork_verify_local_data(ip))
+		goto flush_out;
+	if (xfs_inode_has_attr_fork(ip) &&
+	    ip->i_af.if_format == XFS_DINODE_FMT_LOCAL &&
+	    xfs_ifork_verify_local_attr(ip))
+		goto flush_out;
+
+	/*
+	 * Copy the dirty parts of the inode into the on-disk inode.  We always
+	 * copy out the core of the inode, because if the inode is dirty at all
+	 * the core must be.
+	 */
+	xfs_inode_to_disk(ip, dip, iip->ili_item.li_lsn);
+
+	/* Wrap, we never let the log put out DI_MAX_FLUSH */
+	if (!xfs_has_v3inodes(mp)) {
+		if (ip->i_flushiter == DI_MAX_FLUSH)
+			ip->i_flushiter = 0;
+	}
+
+	xfs_iflush_fork(ip, dip, iip, XFS_DATA_FORK);
+	if (xfs_inode_has_attr_fork(ip))
+		xfs_iflush_fork(ip, dip, iip, XFS_ATTR_FORK);
+
+	/*
+	 * We've recorded everything logged in the inode, so we'd like to clear
+	 * the ili_fields bits so we don't log and flush things unnecessarily.
+	 * However, we can't stop logging all this information until the data
+	 * we've copied into the disk buffer is written to disk.  If we did we
+	 * might overwrite the copy of the inode in the log with all the data
+	 * after re-logging only part of it, and in the face of a crash we
+	 * wouldn't have all the data we need to recover.
+	 *
+	 * What we do is move the bits to the ili_last_fields field.  When
+	 * logging the inode, these bits are moved back to the ili_fields field.
+	 * In the xfs_buf_inode_iodone() routine we clear ili_last_fields, since
+	 * we know that the information those bits represent is permanently on
+	 * disk.  As long as the flush completes before the inode is logged
+	 * again, then both ili_fields and ili_last_fields will be cleared.
+	 */
+	error = 0;
+flush_out:
+	spin_lock(&iip->ili_lock);
+	iip->ili_last_fields = iip->ili_fields;
+	iip->ili_fields = 0;
+	iip->ili_fsync_fields = 0;
+	spin_unlock(&iip->ili_lock);
+
+	/*
+	 * Store the current LSN of the inode so that we can tell whether the
+	 * item has moved in the AIL from xfs_buf_inode_iodone().
+	 */
+	xfs_trans_ail_copy_lsn(mp->m_ail, &iip->ili_flush_lsn,
+				&iip->ili_item.li_lsn);
+
+	/* generate the checksum. */
+	xfs_dinode_calc_crc(mp, dip);
+	return error;
+}
+
+/*
+ * Non-blocking flush of dirty inode metadata into the backing buffer.
+ *
+ * The caller must have a reference to the inode and hold the cluster buffer
+ * locked. The function will walk across all the inodes on the cluster buffer it
+ * can find and lock without blocking, and flush them to the cluster buffer.
+ *
+ * On successful flushing of at least one inode, the caller must write out the
+ * buffer and release it. If no inodes are flushed, -EAGAIN will be returned and
+ * the caller needs to release the buffer. On failure, the filesystem will be
+ * shut down, the buffer will have been unlocked and released, and EFSCORRUPTED
+ * will be returned.
+ */
+int
+xfs_iflush_cluster(
+	struct xfs_buf		*bp)
+{
+	struct xfs_mount	*mp = bp->b_mount;
+	struct xfs_log_item	*lip, *n;
+	struct xfs_inode	*ip;
+	struct xfs_inode_log_item *iip;
+	int			clcount = 0;
+	int			error = 0;
+
+	/*
+	 * We must use the safe variant here as on shutdown xfs_iflush_abort()
+	 * will remove itself from the list.
+	 */
+	list_for_each_entry_safe(lip, n, &bp->b_li_list, li_bio_list) {
+		iip = (struct xfs_inode_log_item *)lip;
+		ip = iip->ili_inode;
+
+		/*
+		 * Quick and dirty check to avoid locks if possible.
+		 */
+		if (__xfs_iflags_test(ip, XFS_IRECLAIM | XFS_IFLUSHING))
+			continue;
+		if (xfs_ipincount(ip))
+			continue;
+
+		/*
+		 * The inode is still attached to the buffer, which means it is
+		 * dirty but reclaim might try to grab it. Check carefully for
+		 * that, and grab the ilock while still holding the i_flags_lock
+		 * to guarantee reclaim will not be able to reclaim this inode
+		 * once we drop the i_flags_lock.
+		 */
+		spin_lock(&ip->i_flags_lock);
+		ASSERT(!__xfs_iflags_test(ip, XFS_ISTALE));
+		if (__xfs_iflags_test(ip, XFS_IRECLAIM | XFS_IFLUSHING)) {
+			spin_unlock(&ip->i_flags_lock);
+			continue;
+		}
+
+		/*
+		 * ILOCK will pin the inode against reclaim and prevent
+		 * concurrent transactions modifying the inode while we are
+		 * flushing the inode. If we get the lock, set the flushing
+		 * state before we drop the i_flags_lock.
+		 */
+		if (!xfs_ilock_nowait(ip, XFS_ILOCK_SHARED)) {
+			spin_unlock(&ip->i_flags_lock);
+			continue;
+		}
+		__xfs_iflags_set(ip, XFS_IFLUSHING);
+		spin_unlock(&ip->i_flags_lock);
+
+		/*
+		 * Abort flushing this inode if we are shut down because the
+		 * inode may not currently be in the AIL. This can occur when
+		 * log I/O failure unpins the inode without inserting into the
+		 * AIL, leaving a dirty/unpinned inode attached to the buffer
+		 * that otherwise looks like it should be flushed.
+		 */
+		if (xlog_is_shutdown(mp->m_log)) {
+			xfs_iunpin_wait(ip);
+			xfs_iflush_abort(ip);
+			xfs_iunlock(ip, XFS_ILOCK_SHARED);
+			error = -EIO;
+			continue;
+		}
+
+		/* don't block waiting on a log force to unpin dirty inodes */
+		if (xfs_ipincount(ip)) {
+			xfs_iflags_clear(ip, XFS_IFLUSHING);
+			xfs_iunlock(ip, XFS_ILOCK_SHARED);
+			continue;
+		}
+
+		if (!xfs_inode_clean(ip))
+			error = xfs_iflush(ip, bp);
+		else
+			xfs_iflags_clear(ip, XFS_IFLUSHING);
+		xfs_iunlock(ip, XFS_ILOCK_SHARED);
+		if (error)
+			break;
+		clcount++;
+	}
+
+	if (error) {
+		/*
+		 * Shutdown first so we kill the log before we release this
+		 * buffer. If it is an INODE_ALLOC buffer and pins the tail
+		 * of the log, failing it before the _log_ is shut down can
+		 * result in the log tail being moved forward in the journal
+		 * on disk because log writes can still be taking place. Hence
+		 * unpinning the tail will allow the ICREATE intent to be
+		 * removed from the log an recovery will fail with uninitialised
+		 * inode cluster buffers.
+		 */
+		xfs_force_shutdown(mp, SHUTDOWN_CORRUPT_INCORE);
+		bp->b_flags |= XBF_ASYNC;
+		xfs_buf_ioend_fail(bp);
+		return error;
+	}
+
+	if (!clcount)
+		return -EAGAIN;
+
+	XFS_STATS_INC(mp, xs_icluster_flushcnt);
+	XFS_STATS_ADD(mp, xs_icluster_flushinode, clcount);
+	return 0;
+
+}
+
+/* Release an inode. */
+void
+xfs_irele(
+	struct xfs_inode	*ip)
+{
+	trace_xfs_irele(ip, _RET_IP_);
+	iput(VFS_I(ip));
+}
+
+/*
+ * Ensure all commited transactions touching the inode are written to the log.
+ */
+int
+xfs_log_force_inode(
+	struct xfs_inode	*ip)
+{
+	xfs_csn_t		seq = 0;
+
+	xfs_ilock(ip, XFS_ILOCK_SHARED);
+	if (xfs_ipincount(ip))
+		seq = ip->i_itemp->ili_commit_seq;
+	xfs_iunlock(ip, XFS_ILOCK_SHARED);
+
+	if (!seq)
+		return 0;
+	return xfs_log_force_seq(ip->i_mount, seq, XFS_LOG_SYNC, NULL);
+}
+
+/*
+ * Grab the exclusive iolock for a data copy from src to dest, making sure to
+ * abide vfs locking order (lowest pointer value goes first) and breaking the
+ * layout leases before proceeding.  The loop is needed because we cannot call
+ * the blocking break_layout() with the iolocks held, and therefore have to
+ * back out both locks.
+ */
+static int
+xfs_iolock_two_inodes_and_break_layout(
+	struct inode		*src,
+	struct inode		*dest)
+{
+	int			error;
+
+	if (src > dest)
+		swap(src, dest);
+
+retry:
+	/* Wait to break both inodes' layouts before we start locking. */
+	error = break_layout(src, true);
+	if (error)
+		return error;
+	if (src != dest) {
+		error = break_layout(dest, true);
+		if (error)
+			return error;
+	}
+
+	/* Lock one inode and make sure nobody got in and leased it. */
+	inode_lock(src);
+	error = break_layout(src, false);
+	if (error) {
+		inode_unlock(src);
+		if (error == -EWOULDBLOCK)
+			goto retry;
+		return error;
+	}
+
+	if (src == dest)
+		return 0;
+
+	/* Lock the other inode and make sure nobody got in and leased it. */
+	inode_lock_nested(dest, I_MUTEX_NONDIR2);
+	error = break_layout(dest, false);
+	if (error) {
+		inode_unlock(src);
+		inode_unlock(dest);
+		if (error == -EWOULDBLOCK)
+			goto retry;
+		return error;
+	}
+
+	return 0;
+}
+
+static int
+xfs_mmaplock_two_inodes_and_break_dax_layout(
+	struct xfs_inode	*ip1,
+	struct xfs_inode	*ip2)
+{
+	int			error;
+	bool			retry;
+	struct page		*page;
+
+	if (ip1->i_ino > ip2->i_ino)
+		swap(ip1, ip2);
+
+again:
+	retry = false;
+	/* Lock the first inode */
+	xfs_ilock(ip1, XFS_MMAPLOCK_EXCL);
+	error = xfs_break_dax_layouts(VFS_I(ip1), &retry);
+	if (error || retry) {
+		xfs_iunlock(ip1, XFS_MMAPLOCK_EXCL);
+		if (error == 0 && retry)
+			goto again;
+		return error;
+	}
+
+	if (ip1 == ip2)
+		return 0;
+
+	/* Nested lock the second inode */
+	xfs_ilock(ip2, xfs_lock_inumorder(XFS_MMAPLOCK_EXCL, 1));
+	/*
+	 * We cannot use xfs_break_dax_layouts() directly here because it may
+	 * need to unlock & lock the XFS_MMAPLOCK_EXCL which is not suitable
+	 * for this nested lock case.
+	 */
+	page = dax_layout_busy_page(VFS_I(ip2)->i_mapping);
+	if (page && page_ref_count(page) != 1) {
+		xfs_iunlock(ip2, XFS_MMAPLOCK_EXCL);
+		xfs_iunlock(ip1, XFS_MMAPLOCK_EXCL);
+		goto again;
+	}
+
+	return 0;
+}
+
+/*
+ * Lock two inodes so that userspace cannot initiate I/O via file syscalls or
+ * mmap activity.
+ */
+int
+xfs_ilock2_io_mmap(
+	struct xfs_inode	*ip1,
+	struct xfs_inode	*ip2)
+{
+	int			ret;
+
+	ret = xfs_iolock_two_inodes_and_break_layout(VFS_I(ip1), VFS_I(ip2));
+	if (ret)
+		return ret;
+
+	if (IS_DAX(VFS_I(ip1)) && IS_DAX(VFS_I(ip2))) {
+		ret = xfs_mmaplock_two_inodes_and_break_dax_layout(ip1, ip2);
+		if (ret) {
+			inode_unlock(VFS_I(ip2));
+			if (ip1 != ip2)
+				inode_unlock(VFS_I(ip1));
+			return ret;
+		}
+	} else
+		filemap_invalidate_lock_two(VFS_I(ip1)->i_mapping,
+					    VFS_I(ip2)->i_mapping);
+
+	return 0;
+}
+
+/* Unlock both inodes to allow IO and mmap activity. */
+void
+xfs_iunlock2_io_mmap(
+	struct xfs_inode	*ip1,
+	struct xfs_inode	*ip2)
+{
+	if (IS_DAX(VFS_I(ip1)) && IS_DAX(VFS_I(ip2))) {
+		xfs_iunlock(ip2, XFS_MMAPLOCK_EXCL);
+		if (ip1 != ip2)
+			xfs_iunlock(ip1, XFS_MMAPLOCK_EXCL);
+	} else
+		filemap_invalidate_unlock_two(VFS_I(ip1)->i_mapping,
+					      VFS_I(ip2)->i_mapping);
+
+	inode_unlock(VFS_I(ip2));
+	if (ip1 != ip2)
+		inode_unlock(VFS_I(ip1));
+}