Fix a number of ext4 bugs.

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

Pull ext4 bug fixes from Ted Ts'o:
 "Fix a number of ext4 bugs"

* tag 'ext4_for_linus_stable' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4:
  ext4: fix special inode number checks in __ext4_iget()
  ext4: track writeback errors using the generic tracking infrastructure
  ext4: use ext4_write_inode() when fsyncing w/o a journal
  ext4: avoid kernel warning when writing the superblock to a dead device
  ext4: fix a potential fiemap/page fault deadlock w/ inline_data
  ext4: make sure enough credits are reserved for dioread_nolock writes

fs/ext4/fsync.c

@@ -116,8 +116,16 @@ int ext4_sync_file(struct file *file, loff_t start, loff_t end, int datasync)
 		goto out;
 	}
 
+	ret = file_write_and_wait_range(file, start, end);
+	if (ret)
+		return ret;
+
 	if (!journal) {
-		ret = __generic_file_fsync(file, start, end, datasync);
+		struct writeback_control wbc = {
+			.sync_mode = WB_SYNC_ALL
+		};
+
+		ret = ext4_write_inode(inode, &wbc);
 		if (!ret)
 			ret = ext4_sync_parent(inode);
 		if (test_opt(inode->i_sb, BARRIER))
@@ -125,9 +133,6 @@ int ext4_sync_file(struct file *file, loff_t start, loff_t end, int datasync)
 		goto out;
 	}
 
-	ret = file_write_and_wait_range(file, start, end);
-	if (ret)
-		return ret;
 	/*
 	 * data=writeback,ordered:
 	 *  The caller's filemap_fdatawrite()/wait will sync the data.
@@ -159,6 +164,9 @@ int ext4_sync_file(struct file *file, loff_t start, loff_t end, int datasync)
 			ret = err;
 	}
 out:
+	err = file_check_and_advance_wb_err(file);
+	if (ret == 0)
+		ret = err;
 	trace_ext4_sync_file_exit(inode, ret);
 	return ret;
 }

fs/ext4/inline.c

@@ -1890,12 +1890,12 @@ int ext4_inline_data_fiemap(struct inode *inode,
 	physical += (char *)ext4_raw_inode(&iloc) - iloc.bh->b_data;
 	physical += offsetof(struct ext4_inode, i_block);
 
-	if (physical)
-		error = fiemap_fill_next_extent(fieinfo, start, physical,
-						inline_len, flags);
 	brelse(iloc.bh);
 out:
 	up_read(&EXT4_I(inode)->xattr_sem);
+	if (physical)
+		error = fiemap_fill_next_extent(fieinfo, start, physical,
+						inline_len, flags);
 	return (error < 0 ? error : 0);
 }
 

fs/ext4/inode.c

@@ -2778,7 +2778,8 @@ static int ext4_writepages(struct address_space *mapping,
 		 * We may need to convert up to one extent per block in
 		 * the page and we may dirty the inode.
 		 */
-		rsv_blocks = 1 + (PAGE_SIZE >> inode->i_blkbits);
+		rsv_blocks = 1 + ext4_chunk_trans_blocks(inode,
+						PAGE_SIZE >> inode->i_blkbits);
 	}
 
 	/*
@@ -4833,7 +4834,7 @@ struct inode *__ext4_iget(struct super_block *sb, unsigned long ino,
 	gid_t i_gid;
 	projid_t i_projid;
 
-	if (((flags & EXT4_IGET_NORMAL) &&
+	if ((!(flags & EXT4_IGET_SPECIAL) &&
 	     (ino < EXT4_FIRST_INO(sb) && ino != EXT4_ROOT_INO)) ||
 	    (ino < EXT4_ROOT_INO) ||
 	    (ino > le32_to_cpu(EXT4_SB(sb)->s_es->s_inodes_count))) {

fs/ext4/super.c

@@ -4902,7 +4902,7 @@ static int ext4_commit_super(struct super_block *sb, int sync)
 	ext4_superblock_csum_set(sb);
 	if (sync)
 		lock_buffer(sbh);
-	if (buffer_write_io_error(sbh)) {
+	if (buffer_write_io_error(sbh) || !buffer_uptodate(sbh)) {
 		/*
 		 * Oh, dear.  A previous attempt to write the
 		 * superblock failed.  This could happen because the