Merge tag 'ext4_for_linus_stable' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4

Pull ext4 fixes from Ted Ts'o:
 "Fix some syzbot-detected bugs, as well as other bugs found by I/O
  injection testing.

  Change ext4's fallocate to consistently drop set[ug]id bits when an
  fallocate operation might possibly change the user-visible contents of
  a file.

  Also, improve handling of potentially invalid values in the the
  s_overhead_cluster superblock field to avoid ext4 returning a negative
  number of free blocks"

* tag 'ext4_for_linus_stable' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4:
  jbd2: fix a potential race while discarding reserved buffers after an abort
  ext4: update the cached overhead value in the superblock
  ext4: force overhead calculation if the s_overhead_cluster makes no sense
  ext4: fix overhead calculation to account for the reserved gdt blocks
  ext4, doc: fix incorrect h_reserved size
  ext4: limit length to bitmap_maxbytes - blocksize in punch_hole
  ext4: fix use-after-free in ext4_search_dir
  ext4: fix bug_on in start_this_handle during umount filesystem
  ext4: fix symlink file size not match to file content
  ext4: fix fallocate to use file_modified to update permissions consistently

1 files changed, 16 insertions, 2 deletions

diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 13740f2d0e61..646ece9b3455 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -3953,12 +3953,14 @@ int ext4_break_layouts(struct inode *inode)
  * Returns: 0 on success or negative on failure
  */
 
-int ext4_punch_hole(struct inode *inode, loff_t offset, loff_t length)
+int ext4_punch_hole(struct file *file, loff_t offset, loff_t length)
 {
+	struct inode *inode = file_inode(file);
 	struct super_block *sb = inode->i_sb;
 	ext4_lblk_t first_block, stop_block;
 	struct address_space *mapping = inode->i_mapping;
-	loff_t first_block_offset, last_block_offset;
+	loff_t first_block_offset, last_block_offset, max_length;
+	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
 	handle_t *handle;
 	unsigned int credits;
 	int ret = 0, ret2 = 0;
@@ -4001,6 +4003,14 @@ int ext4_punch_hole(struct inode *inode, loff_t offset, loff_t length)
 		   offset;
 	}
 
+	/*
+	 * For punch hole the length + offset needs to be within one block
+	 * before last range. Adjust the length if it goes beyond that limit.
+	 */
+	max_length = sbi->s_bitmap_maxbytes - inode->i_sb->s_blocksize;
+	if (offset + length > max_length)
+		length = max_length - offset;
+
 	if (offset & (sb->s_blocksize - 1) ||
 	    (offset + length) & (sb->s_blocksize - 1)) {
 		/*
@@ -4016,6 +4026,10 @@ int ext4_punch_hole(struct inode *inode, loff_t offset, loff_t length)
 	/* Wait all existing dio workers, newcomers will block on i_rwsem */
 	inode_dio_wait(inode);
 
+	ret = file_modified(file);
+	if (ret)
+		goto out_mutex;
+
 	/*
 	 * Prevent page faults from reinstantiating pages we have released from
 	 * page cache.