linux-kernel - [PATCH 4.14 37/53] f2fs: truncate preallocated blocks in error case

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Date:   Tue, 10 Jul 2018 20:25:13 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Chao Yu <yuchao0@...wei.com>,
        Jaegeuk Kim <jaegeuk@...nel.org>,
        Sudip Mukherjee <sudipm.mukherjee@...il.com>
Subject: [PATCH 4.14 37/53] f2fs: truncate preallocated blocks in error case

4.14-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Jaegeuk Kim <jaegeuk@...nel.org>

commit dc7a10ddee0c56c6d891dd18de5c4ee9869545e0 upstream.

If write is failed, we must deallocate the blocks that we couldn't write.

Cc: stable@...r.kernel.org
Reviewed-by: Chao Yu <yuchao0@...wei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@...nel.org>
Signed-off-by: Sudip Mukherjee <sudipm.mukherjee@...il.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
---
 fs/f2fs/file.c |    9 +++++++++
 1 file changed, 9 insertions(+)

--- a/fs/f2fs/file.c
+++ b/fs/f2fs/file.c
@@ -2694,11 +2694,16 @@ static ssize_t f2fs_file_write_iter(stru
 	inode_lock(inode);
 	ret = generic_write_checks(iocb, from);
 	if (ret > 0) {
+		bool preallocated = false;
+		size_t target_size = 0;
 		int err;
 
 		if (iov_iter_fault_in_readable(from, iov_iter_count(from)))
 			set_inode_flag(inode, FI_NO_PREALLOC);
 
+		preallocated = true;
+		target_size = iocb->ki_pos + iov_iter_count(from);
+
 		err = f2fs_preallocate_blocks(iocb, from);
 		if (err) {
 			clear_inode_flag(inode, FI_NO_PREALLOC);
@@ -2710,6 +2715,10 @@ static ssize_t f2fs_file_write_iter(stru
 		blk_finish_plug(&plug);
 		clear_inode_flag(inode, FI_NO_PREALLOC);
 
+		/* if we couldn't write data, we should deallocate blocks. */
+		if (preallocated && i_size_read(inode) < target_size)
+			f2fs_truncate(inode);
+
 		if (ret > 0)
 			f2fs_update_iostat(F2FS_I_SB(inode), APP_WRITE_IO, ret);
 	}