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From 1267a07be5ebbff2d2739290f3d043ae137c15b4 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Ernesto=20A=2E=20Fern=C3=A1ndez?=
 <ernesto.mnd.fernandez@gmail.com>
Date: Tue, 30 Oct 2018 15:06:24 -0700
Subject: [PATCH] hfs: fix return value of hfs_get_block()
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Git-commit: 1267a07be5ebbff2d2739290f3d043ae137c15b4
Patch-mainline: v4.20-rc1
References: git-fixes

Direct writes to empty inodes fail with EIO.  The generic direct-io code
is in part to blame (a patch has been submitted as "direct-io: allow
direct writes to empty inodes"), but hfs is worse affected than the other
filesystems because the fallback to buffered I/O doesn't happen.

The problem is the return value of hfs_get_block() when called with
!create.  Change it to be more consistent with the other modules.

Link: http://lkml.kernel.org/r/4538ab8c35ea37338490525f0f24cbc37227528c.1539195310.git.ernesto.mnd.fernandez@gmail.com
Signed-off-by: Ernesto A. Fernández <ernesto.mnd.fernandez@gmail.com>
Reviewed-by: Vyacheslav Dubeyko <slava@dubeyko.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Acked-by: Anthony Iliopoulos <ailiop@suse.com>

---
 fs/hfs/extent.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/fs/hfs/extent.c b/fs/hfs/extent.c
index 0c638c612152..5f1ff97a3b98 100644
--- a/fs/hfs/extent.c
+++ b/fs/hfs/extent.c
@@ -345,7 +345,9 @@ int hfs_get_block(struct inode *inode, sector_t block,
 	ablock = (u32)block / HFS_SB(sb)->fs_div;
 
 	if (block >= HFS_I(inode)->fs_blocks) {
-		if (block > HFS_I(inode)->fs_blocks || !create)
+		if (!create)
+			return 0;
+		if (block > HFS_I(inode)->fs_blocks)
 			return -EIO;
 		if (ablock >= HFS_I(inode)->alloc_blocks) {
 			res = hfs_extend_file(inode);
-- 
2.35.3