x86/kprobes: Fix crash when probing CS CALL instructionsgrafted

When using eBPF to probe CS CALL instructions within a function,
a crash can be triggered.

The eBPF tool probes offset 257 of the __hrtimer_run_queues()
function:

<__hrtimer_run_queues+249>:  nopl   0x0(%rax,%rax,1)
<__hrtimer_run_queues+254>:  mov    %r14,%rdi
<__hrtimer_run_queues+257>:  cs call <__x86_indirect_thunk_r12>
<__hrtimer_run_queues+263>:  mov    %eax,%r12d
<__hrtimer_run_queues+266>:  xchg   %ax,%ax
<__hrtimer_run_queues+268>:  mov    %r13,%rdi

Which triggers this crash:

  BUG: unable to handle page fault for address: 00000000000f41c9
  #PF: supervisor write access in kernel mode
  #PF: error_code(0x0002) - not-present page
  PGD 0 P4D 0
  Oops: 0002 [#1] SMP NOPTI
  CPU: 1 PID: 0 Comm: swapper/1 Kdump: loaded Tainted: P
  RIP: 0010:__hrtimer_run_queues+0x106/0x230

Note that __hrtimer_run_queues+0x106 is __hrtimer_run_queues+262, which is
at the 6th byte of the above CS CALL instruction. Since the CS CALL
instruction occupies 6 bytes, the exception occurred in the middle of that
call instruction.

The root cause is that when using eBPF tools to probe in the middle of a
function, a kprobe with INT3 is used as the underlying implementation.

During single-step emulation of the original CALL instruction,
int3_emulate_call() assumes that the probed CALL instruction is 5 bytes
long. However, the actual CS-prefixed CALL instruction occupies 6 bytes,
so it constructs an incorrect exception return address. When the CPU
returns from the kprobe handler, the next instruction to be executed is at
the address of the last byte of that CS CALL instruction. Coincidentally,
starting from that address, the CPU fetches and decodes a completely
different instruction, which ultimately triggers a kernel crash.

Fix the issue by using the actual instruction length obtained from
the instruction decoder when constructing the exception return
address, rather than relying on the hardcoded CALL_INSN_SIZE macro.

[ mingo: Refined the changelog ]

Fixes: 6256e668b7af ("x86/kprobes: Use int3 instead of debug trap for single-step")
Suggested-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Jinke Han <jinkehan@didiglobal.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Acked-by: Yafang Shao <laoar.shao@gmail.com>
Acked-by: Borislav Petkov <bp@alien8.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://patch.msgid.link/20260908073742.GA10517@didi-ThinkCentre-M920t-N000

1 files changed, 636 insertions, 0 deletions

diff --git a/fs/hfsplus/extents.c b/fs/hfsplus/extents.c
new file mode 100644
index 000000000..eb7c11524
--- /dev/null
+++ b/fs/hfsplus/extents.c
@@ -0,0 +1,636 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ *  linux/fs/hfsplus/extents.c
+ *
+ * Copyright (C) 2001
+ * Brad Boyer (flar@allandria.com)
+ * (C) 2003 Ardis Technologies <roman@ardistech.com>
+ *
+ * Handling of Extents both in catalog and extents overflow trees
+ */
+
+#include <linux/errno.h>
+#include <linux/fs.h>
+#include <linux/pagemap.h>
+
+#include "hfsplus_fs.h"
+#include "hfsplus_raw.h"
+
+/* Compare two extents keys, returns 0 on same, pos/neg for difference */
+int hfsplus_ext_cmp_key(const hfsplus_btree_key *k1,
+			const hfsplus_btree_key *k2)
+{
+	__be32 k1id, k2id;
+	__be32 k1s, k2s;
+
+	k1id = k1->ext.cnid;
+	k2id = k2->ext.cnid;
+	if (k1id != k2id)
+		return be32_to_cpu(k1id) < be32_to_cpu(k2id) ? -1 : 1;
+
+	if (k1->ext.fork_type != k2->ext.fork_type)
+		return k1->ext.fork_type < k2->ext.fork_type ? -1 : 1;
+
+	k1s = k1->ext.start_block;
+	k2s = k2->ext.start_block;
+	if (k1s == k2s)
+		return 0;
+	return be32_to_cpu(k1s) < be32_to_cpu(k2s) ? -1 : 1;
+}
+
+static void hfsplus_ext_build_key(hfsplus_btree_key *key, u32 cnid,
+				  u32 block, u8 type)
+{
+	key->key_len = cpu_to_be16(HFSPLUS_EXT_KEYLEN - 2);
+	key->ext.cnid = cpu_to_be32(cnid);
+	key->ext.start_block = cpu_to_be32(block);
+	key->ext.fork_type = type;
+	key->ext.pad = 0;
+}
+
+static u32 hfsplus_ext_find_block(struct hfsplus_extent *ext, u32 off)
+{
+	int i;
+	u32 count;
+
+	for (i = 0; i < 8; ext++, i++) {
+		count = be32_to_cpu(ext->block_count);
+		if (off < count)
+			return be32_to_cpu(ext->start_block) + off;
+		off -= count;
+	}
+	/* panic? */
+	return 0;
+}
+
+static int hfsplus_ext_block_count(struct hfsplus_extent *ext)
+{
+	int i;
+	u32 count = 0;
+
+	for (i = 0; i < 8; ext++, i++)
+		count += be32_to_cpu(ext->block_count);
+	return count;
+}
+
+static u32 hfsplus_ext_lastblock(struct hfsplus_extent *ext)
+{
+	int i;
+
+	ext += 7;
+	for (i = 0; i < 7; ext--, i++)
+		if (ext->block_count)
+			break;
+	return be32_to_cpu(ext->start_block) + be32_to_cpu(ext->block_count);
+}
+
+static int __hfsplus_ext_write_extent(struct inode *inode,
+		struct hfs_find_data *fd)
+{
+	struct hfsplus_inode_info *hip = HFSPLUS_I(inode);
+	int res;
+
+	WARN_ON(!mutex_is_locked(&hip->extents_lock));
+
+	hfsplus_ext_build_key(fd->search_key, inode->i_ino, hip->cached_start,
+			      HFSPLUS_IS_RSRC(inode) ?
+				HFSPLUS_TYPE_RSRC : HFSPLUS_TYPE_DATA);
+
+	res = hfs_brec_find(fd, hfs_find_rec_by_key);
+	if (hip->extent_state & HFSPLUS_EXT_NEW) {
+		if (res != -ENOENT)
+			return res;
+		/* Fail early and avoid ENOSPC during the btree operation */
+		res = hfs_bmap_reserve(fd->tree, fd->tree->depth + 1);
+		if (res)
+			return res;
+		hfs_brec_insert(fd, hip->cached_extents,
+				sizeof(hfsplus_extent_rec));
+		hip->extent_state &= ~(HFSPLUS_EXT_DIRTY | HFSPLUS_EXT_NEW);
+	} else {
+		if (res)
+			return res;
+		if (fd->entrylength != sizeof(hfsplus_extent_rec))
+			return -EIO;
+		hfs_bnode_write(fd->bnode, hip->cached_extents,
+				fd->entryoffset, fd->entrylength);
+		hip->extent_state &= ~HFSPLUS_EXT_DIRTY;
+	}
+
+	/*
+	 * We can't just use hfsplus_mark_inode_dirty here, because we
+	 * also get called from hfsplus_write_inode, which should not
+	 * redirty the inode.  Instead the callers have to be careful
+	 * to explicily mark the inode dirty, too.
+	 */
+	set_bit(HFSPLUS_I_EXT_DIRTY,
+		&HFSPLUS_I(HFSPLUS_EXT_TREE_I(inode->i_sb))->flags);
+	set_bit(HFSPLUS_I_EXT_DIRTY, &hip->flags);
+
+	return 0;
+}
+
+static int hfsplus_ext_write_extent_locked(struct inode *inode)
+{
+	int res = 0;
+
+	if (HFSPLUS_I(inode)->extent_state & HFSPLUS_EXT_DIRTY) {
+		struct hfs_find_data fd;
+
+		res = hfs_find_init(HFSPLUS_SB(inode->i_sb)->ext_tree, &fd);
+		if (res)
+			return res;
+		res = __hfsplus_ext_write_extent(inode, &fd);
+		hfs_find_exit(&fd);
+	}
+	return res;
+}
+
+int hfsplus_ext_write_extent(struct inode *inode)
+{
+	int res;
+
+	mutex_lock(&HFSPLUS_I(inode)->extents_lock);
+	res = hfsplus_ext_write_extent_locked(inode);
+	mutex_unlock(&HFSPLUS_I(inode)->extents_lock);
+
+	return res;
+}
+
+static inline int __hfsplus_ext_read_extent(struct hfs_find_data *fd,
+					    struct hfsplus_extent *extent,
+					    u32 cnid, u32 block, u8 type)
+{
+	int res;
+
+	hfsplus_ext_build_key(fd->search_key, cnid, block, type);
+	fd->key->ext.cnid = 0;
+	res = hfs_brec_find(fd, hfs_find_rec_by_key);
+	if (res && res != -ENOENT)
+		return res;
+	if (fd->key->ext.cnid != fd->search_key->ext.cnid ||
+	    fd->key->ext.fork_type != fd->search_key->ext.fork_type)
+		return -ENOENT;
+	if (fd->entrylength != sizeof(hfsplus_extent_rec))
+		return -EIO;
+	hfs_bnode_read(fd->bnode, extent, fd->entryoffset,
+		sizeof(hfsplus_extent_rec));
+	return 0;
+}
+
+static inline int __hfsplus_ext_cache_extent(struct hfs_find_data *fd,
+		struct inode *inode, u32 block)
+{
+	struct hfsplus_inode_info *hip = HFSPLUS_I(inode);
+	int res;
+
+	WARN_ON(!mutex_is_locked(&hip->extents_lock));
+
+	if (hip->extent_state & HFSPLUS_EXT_DIRTY) {
+		res = __hfsplus_ext_write_extent(inode, fd);
+		if (res)
+			return res;
+	}
+
+	res = __hfsplus_ext_read_extent(fd, hip->cached_extents, inode->i_ino,
+					block, HFSPLUS_IS_RSRC(inode) ?
+						HFSPLUS_TYPE_RSRC :
+						HFSPLUS_TYPE_DATA);
+	if (!res) {
+		hip->cached_start = be32_to_cpu(fd->key->ext.start_block);
+		hip->cached_blocks =
+			hfsplus_ext_block_count(hip->cached_extents);
+	} else {
+		hip->cached_start = hip->cached_blocks = 0;
+		hip->extent_state &= ~(HFSPLUS_EXT_DIRTY | HFSPLUS_EXT_NEW);
+	}
+	return res;
+}
+
+static int hfsplus_ext_read_extent(struct inode *inode, u32 block)
+{
+	struct hfsplus_inode_info *hip = HFSPLUS_I(inode);
+	struct hfs_find_data fd;
+	int res;
+
+	if (block >= hip->cached_start &&
+	    block < hip->cached_start + hip->cached_blocks)
+		return 0;
+
+	res = hfs_find_init(HFSPLUS_SB(inode->i_sb)->ext_tree, &fd);
+	if (!res) {
+		res = __hfsplus_ext_cache_extent(&fd, inode, block);
+		hfs_find_exit(&fd);
+	}
+	return res;
+}
+
+/* Get a block at iblock for inode, possibly allocating if create */
+int hfsplus_get_block(struct inode *inode, sector_t iblock,
+		      struct buffer_head *bh_result, int create)
+{
+	struct super_block *sb = inode->i_sb;
+	struct hfsplus_sb_info *sbi = HFSPLUS_SB(sb);
+	struct hfsplus_inode_info *hip = HFSPLUS_I(inode);
+	int res = -EIO;
+	u32 ablock, dblock, mask;
+	sector_t sector;
+	int was_dirty = 0;
+
+	/* Convert inode block to disk allocation block */
+	ablock = iblock >> sbi->fs_shift;
+
+	if (iblock >= hip->fs_blocks) {
+		if (!create)
+			return 0;
+		if (iblock > hip->fs_blocks)
+			return -EIO;
+		if (ablock >= hip->alloc_blocks) {
+			res = hfsplus_file_extend(inode, false);
+			if (res)
+				return res;
+		}
+	} else
+		create = 0;
+
+	if (ablock < hip->first_blocks) {
+		dblock = hfsplus_ext_find_block(hip->first_extents, ablock);
+		goto done;
+	}
+
+	if (inode->i_ino == HFSPLUS_EXT_CNID)
+		return -EIO;
+
+	mutex_lock(&hip->extents_lock);
+
+	/*
+	 * hfsplus_ext_read_extent will write out a cached extent into
+	 * the extents btree.  In that case we may have to mark the inode
+	 * dirty even for a pure read of an extent here.
+	 */
+	was_dirty = (hip->extent_state & HFSPLUS_EXT_DIRTY);
+	res = hfsplus_ext_read_extent(inode, ablock);
+	if (res) {
+		mutex_unlock(&hip->extents_lock);
+		return -EIO;
+	}
+	dblock = hfsplus_ext_find_block(hip->cached_extents,
+					ablock - hip->cached_start);
+	mutex_unlock(&hip->extents_lock);
+
+done:
+	hfs_dbg("ino %llu, iblock %llu - dblock %u\n",
+		inode->i_ino, (long long)iblock, dblock);
+
+	mask = (1 << sbi->fs_shift) - 1;
+	sector = ((sector_t)dblock << sbi->fs_shift) +
+		  sbi->blockoffset + (iblock & mask);
+	map_bh(bh_result, sb, sector);
+
+	if (create) {
+		set_buffer_new(bh_result);
+		hip->phys_size += sb->s_blocksize;
+		hip->fs_blocks++;
+		inode_add_bytes(inode, sb->s_blocksize);
+	}
+	if (create || was_dirty)
+		mark_inode_dirty(inode);
+	return 0;
+}
+
+static void hfsplus_dump_extent(struct hfsplus_extent *extent)
+{
+	int i;
+
+	hfs_dbg("extent   ");
+	for (i = 0; i < 8; i++)
+		hfs_dbg(" start_block %u, block_count %u",
+			be32_to_cpu(extent[i].start_block),
+			be32_to_cpu(extent[i].block_count));
+	hfs_dbg("\n");
+}
+
+static int hfsplus_add_extent(struct hfsplus_extent *extent, u32 offset,
+			      u32 alloc_block, u32 block_count)
+{
+	u32 count, start;
+	int i;
+
+	hfsplus_dump_extent(extent);
+	for (i = 0; i < 8; extent++, i++) {
+		count = be32_to_cpu(extent->block_count);
+		if (offset == count) {
+			start = be32_to_cpu(extent->start_block);
+			if (alloc_block != start + count) {
+				if (++i >= 8)
+					return -ENOSPC;
+				extent++;
+				extent->start_block = cpu_to_be32(alloc_block);
+			} else
+				block_count += count;
+			extent->block_count = cpu_to_be32(block_count);
+			return 0;
+		} else if (offset < count)
+			break;
+		offset -= count;
+	}
+	/* panic? */
+	return -EIO;
+}
+
+static int hfsplus_free_extents(struct super_block *sb,
+				struct hfsplus_extent *extent,
+				u32 offset, u32 block_nr)
+{
+	u32 count, start;
+	int i;
+	int err = 0;
+
+	hfsplus_dump_extent(extent);
+	for (i = 0; i < 8; extent++, i++) {
+		count = be32_to_cpu(extent->block_count);
+		if (offset == count)
+			goto found;
+		else if (offset < count)
+			break;
+		offset -= count;
+	}
+	/* panic? */
+	return -EIO;
+found:
+	for (;;) {
+		start = be32_to_cpu(extent->start_block);
+		if (count <= block_nr) {
+			err = hfsplus_block_free(sb, start, count);
+			if (err) {
+				pr_err("can't free extent: start %u, count %u\n",
+					start, count);
+			}
+			extent->block_count = 0;
+			extent->start_block = 0;
+			block_nr -= count;
+		} else {
+			count -= block_nr;
+			err = hfsplus_block_free(sb, start + count, block_nr);
+			if (err) {
+				pr_err("can't free extent: start %u, count %u\n",
+					start, count);
+			}
+			extent->block_count = cpu_to_be32(count);
+			block_nr = 0;
+		}
+		if (!block_nr || !i) {
+			/*
+			 * Try to free all extents and
+			 * return only last error
+			 */
+			return err;
+		}
+		i--;
+		extent--;
+		count = be32_to_cpu(extent->block_count);
+	}
+}
+
+int hfsplus_free_fork(struct super_block *sb, u32 cnid,
+		struct hfsplus_fork_raw *fork, int type)
+{
+	struct hfs_find_data fd;
+	hfsplus_extent_rec ext_entry;
+	u32 total_blocks, blocks, start;
+	int res, i;
+
+	total_blocks = be32_to_cpu(fork->total_blocks);
+	if (!total_blocks)
+		return 0;
+
+	blocks = 0;
+	for (i = 0; i < 8; i++)
+		blocks += be32_to_cpu(fork->extents[i].block_count);
+
+	res = hfsplus_free_extents(sb, fork->extents, blocks, blocks);
+	if (res)
+		return res;
+	if (total_blocks == blocks)
+		return 0;
+
+	res = hfs_find_init(HFSPLUS_SB(sb)->ext_tree, &fd);
+	if (res)
+		return res;
+	do {
+		res = __hfsplus_ext_read_extent(&fd, ext_entry, cnid,
+						total_blocks, type);
+		if (res)
+			break;
+		start = be32_to_cpu(fd.key->ext.start_block);
+		hfs_brec_remove(&fd);
+
+		mutex_unlock(&fd.tree->tree_lock);
+		hfsplus_free_extents(sb, ext_entry, total_blocks - start,
+				     total_blocks);
+		total_blocks = start;
+		mutex_lock_nested(&fd.tree->tree_lock,
+			hfsplus_btree_lock_class(fd.tree));
+	} while (total_blocks > blocks);
+	hfs_find_exit(&fd);
+
+	return res;
+}
+
+int hfsplus_file_extend(struct inode *inode, bool zeroout)
+{
+	struct super_block *sb = inode->i_sb;
+	struct hfsplus_sb_info *sbi = HFSPLUS_SB(sb);
+	struct hfsplus_inode_info *hip = HFSPLUS_I(inode);
+	u32 start, len, goal;
+	int res;
+
+	if (sbi->alloc_file->i_size * 8 <
+	    sbi->total_blocks - sbi->free_blocks + 8) {
+		/* extend alloc file */
+		pr_err_ratelimited("extend alloc file! (%llu,%u,%u)\n",
+				   sbi->alloc_file->i_size * 8,
+				   sbi->total_blocks, sbi->free_blocks);
+		return -ENOSPC;
+	}
+
+	mutex_lock(&hip->extents_lock);
+	if (hip->alloc_blocks == hip->first_blocks)
+		goal = hfsplus_ext_lastblock(hip->first_extents);
+	else {
+		res = hfsplus_ext_read_extent(inode, hip->alloc_blocks);
+		if (res)
+			goto out;
+		goal = hfsplus_ext_lastblock(hip->cached_extents);
+	}
+
+	len = hip->clump_blocks;
+	start = hfsplus_block_allocate(sb, sbi->total_blocks, goal, &len);
+	if (start >= sbi->total_blocks) {
+		start = hfsplus_block_allocate(sb, goal, 0, &len);
+		if (start >= goal) {
+			res = -ENOSPC;
+			goto out;
+		}
+	}
+
+	if (zeroout) {
+		res = sb_issue_zeroout(sb, start, len, GFP_NOFS);
+		if (res)
+			goto out;
+	}
+
+	hfs_dbg("ino %llu, start %u, len %u\n", inode->i_ino, start, len);
+
+	if (hip->alloc_blocks <= hip->first_blocks) {
+		if (!hip->first_blocks) {
+			hfs_dbg("first_extent: start %u, len %u\n",
+				start, len);
+			/* no extents yet */
+			hip->first_extents[0].start_block = cpu_to_be32(start);
+			hip->first_extents[0].block_count = cpu_to_be32(len);
+			res = 0;
+		} else {
+			/* try to append to extents in inode */
+			res = hfsplus_add_extent(hip->first_extents,
+						 hip->alloc_blocks,
+						 start, len);
+			if (res == -ENOSPC)
+				goto insert_extent;
+		}
+		if (!res) {
+			hfsplus_dump_extent(hip->first_extents);
+			hip->first_blocks += len;
+		}
+	} else {
+		res = hfsplus_add_extent(hip->cached_extents,
+					 hip->alloc_blocks - hip->cached_start,
+					 start, len);
+		if (!res) {
+			hfsplus_dump_extent(hip->cached_extents);
+			hip->extent_state |= HFSPLUS_EXT_DIRTY;
+			hip->cached_blocks += len;
+		} else if (res == -ENOSPC)
+			goto insert_extent;
+	}
+out:
+	if (!res) {
+		hip->alloc_blocks += len;
+		mutex_unlock(&hip->extents_lock);
+		hfsplus_mark_inode_dirty(HFSPLUS_SB(sb)->alloc_file,
+					 HFSPLUS_I_ALLOC_DIRTY);
+		hfsplus_mark_inode_dirty(inode, HFSPLUS_I_ALLOC_DIRTY);
+		return 0;
+	}
+	mutex_unlock(&hip->extents_lock);
+	return res;
+
+insert_extent:
+	hfs_dbg("insert new extent\n");
+	res = hfsplus_ext_write_extent_locked(inode);
+	if (res)
+		goto out;
+
+	memset(hip->cached_extents, 0, sizeof(hfsplus_extent_rec));
+	hip->cached_extents[0].start_block = cpu_to_be32(start);
+	hip->cached_extents[0].block_count = cpu_to_be32(len);
+	hfsplus_dump_extent(hip->cached_extents);
+	hip->extent_state |= HFSPLUS_EXT_DIRTY | HFSPLUS_EXT_NEW;
+	hip->cached_start = hip->alloc_blocks;
+	hip->cached_blocks = len;
+
+	res = 0;
+	goto out;
+}
+
+void hfsplus_file_truncate(struct inode *inode)
+{
+	struct super_block *sb = inode->i_sb;
+	struct hfsplus_inode_info *hip = HFSPLUS_I(inode);
+	struct hfs_find_data fd;
+	u32 alloc_cnt, blk_cnt, start;
+	int res;
+
+	hfs_dbg("ino %llu, phys_size %llu -> i_size %llu\n",
+		inode->i_ino, (long long)hip->phys_size, inode->i_size);
+
+	if (inode->i_size > hip->phys_size) {
+		struct address_space *mapping = inode->i_mapping;
+		struct folio *folio;
+		void *fsdata = NULL;
+		loff_t size = inode->i_size;
+
+		res = hfsplus_write_begin(NULL, mapping, size, 0,
+					  &folio, &fsdata);
+		if (res)
+			return;
+		res = generic_write_end(NULL, mapping, size, 0, 0,
+					folio, fsdata);
+		if (res < 0)
+			return;
+		mark_inode_dirty(inode);
+		return;
+	} else if (inode->i_size == hip->phys_size)
+		return;
+
+	blk_cnt = (inode->i_size + HFSPLUS_SB(sb)->alloc_blksz - 1) >>
+			HFSPLUS_SB(sb)->alloc_blksz_shift;
+
+	mutex_lock(&hip->extents_lock);
+
+	alloc_cnt = hip->alloc_blocks;
+	if (blk_cnt == alloc_cnt)
+		goto out_unlock;
+
+	res = hfs_find_init(HFSPLUS_SB(sb)->ext_tree, &fd);
+	if (res) {
+		mutex_unlock(&hip->extents_lock);
+		/* XXX: We lack error handling of hfsplus_file_truncate() */
+		return;
+	}
+
+	while (1) {
+		if (alloc_cnt == hip->first_blocks) {
+			mutex_unlock(&fd.tree->tree_lock);
+			hfsplus_free_extents(sb, hip->first_extents,
+					     alloc_cnt, alloc_cnt - blk_cnt);
+			hfsplus_dump_extent(hip->first_extents);
+			hip->first_blocks = blk_cnt;
+			mutex_lock_nested(&fd.tree->tree_lock,
+				hfsplus_btree_lock_class(fd.tree));
+			break;
+		}
+		res = __hfsplus_ext_cache_extent(&fd, inode, alloc_cnt);
+		if (res)
+			break;
+
+		start = hip->cached_start;
+		if (blk_cnt <= start)
+			hfs_brec_remove(&fd);
+		mutex_unlock(&fd.tree->tree_lock);
+		hfsplus_free_extents(sb, hip->cached_extents,
+				     alloc_cnt - start, alloc_cnt - blk_cnt);
+		hfsplus_dump_extent(hip->cached_extents);
+		mutex_lock_nested(&fd.tree->tree_lock,
+				hfsplus_btree_lock_class(fd.tree));
+		if (blk_cnt > start) {
+			hip->extent_state |= HFSPLUS_EXT_DIRTY;
+			break;
+		}
+		alloc_cnt = start;
+		hip->cached_start = hip->cached_blocks = 0;
+		hip->extent_state &= ~(HFSPLUS_EXT_DIRTY | HFSPLUS_EXT_NEW);
+	}
+	hfs_find_exit(&fd);
+
+	hip->alloc_blocks = blk_cnt;
+out_unlock:
+	mutex_unlock(&hip->extents_lock);
+	hip->phys_size = inode->i_size;
+	hip->fs_blocks = (inode->i_size + sb->s_blocksize - 1) >>
+		sb->s_blocksize_bits;
+	inode_set_bytes(inode, hip->fs_blocks << sb->s_blocksize_bits);
+	hfsplus_mark_inode_dirty(HFSPLUS_SB(sb)->alloc_file,
+				 HFSPLUS_I_ALLOC_DIRTY);
+	hfsplus_mark_inode_dirty(inode, HFSPLUS_I_ALLOC_DIRTY);
+}