FAILED: patch "[PATCH] udf: Preserve link count of system files" failed to apply to 4.14-stable tree

[<gregkh@linuxfoundation.org>]

The patch below does not apply to the 4.14-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@vger.kernel.org>.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-4.14.y
git checkout FETCH_HEAD
git cherry-pick -x fc8033a34a3ca7d23353e645e6dde5d364ac5f12
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable@vger.kernel.org>' --in-reply-to '167810996089240@kroah.com' --subject-prefix 'PATCH 4.14.y' HEAD^..

Possible dependencies:

fc8033a34a3c ("udf: Preserve link count of system files")
382a2287bf9c ("udf: Remove pointless union in udf_inode_info")
044e2e26f214 ("udf: Avoid accessing uninitialized data on failed inode read")
ab9a3a737284 ("udf: reduce leakage of blocks related to named streams")
d288d95842f1 ("udf: Fix BUG on corrupted inode")

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From fc8033a34a3ca7d23353e645e6dde5d364ac5f12 Mon Sep 17 00:00:00 2001
From: Jan Kara <jack@suse.cz>
Date: Tue, 3 Jan 2023 09:56:56 +0100
Subject: [PATCH] udf: Preserve link count of system files

System files in UDF filesystem have link count 0. To not confuse VFS we
fudge the link count to be 1 when reading such inodes however we forget
to restore the link count of 0 when writing such inodes. Fix that.

CC: stable@vger.kernel.org
Signed-off-by: Jan Kara <jack@suse.cz>

diff --git a/fs/udf/inode.c b/fs/udf/inode.c
index 31965c3798f2..9ee269d3d546 100644
--- a/fs/udf/inode.c
+++ b/fs/udf/inode.c
@@ -1301,6 +1301,7 @@ static int udf_read_inode(struct inode *inode, bool hidden_inode)
 		ret = -EIO;
 		goto out;
 	}
+	iinfo->i_hidden = hidden_inode;
 	iinfo->i_unique = 0;
 	iinfo->i_lenEAttr = 0;
 	iinfo->i_lenExtents = 0;
@@ -1636,8 +1637,12 @@ static int udf_update_inode(struct inode *inode, int do_sync)
 
 	if (S_ISDIR(inode->i_mode) && inode->i_nlink > 0)
 		fe->fileLinkCount = cpu_to_le16(inode->i_nlink - 1);
-	else
-		fe->fileLinkCount = cpu_to_le16(inode->i_nlink);
+	else {
+		if (iinfo->i_hidden)
+			fe->fileLinkCount = cpu_to_le16(0);
+		else
+			fe->fileLinkCount = cpu_to_le16(inode->i_nlink);
+	}
 
 	fe->informationLength = cpu_to_le64(inode->i_size);
 
diff --git a/fs/udf/super.c b/fs/udf/super.c
index 06eda8177b5f..241b40e886b3 100644
--- a/fs/udf/super.c
+++ b/fs/udf/super.c
@@ -147,6 +147,7 @@ static struct inode *udf_alloc_inode(struct super_block *sb)
 	ei->i_next_alloc_goal = 0;
 	ei->i_strat4096 = 0;
 	ei->i_streamdir = 0;
+	ei->i_hidden = 0;
 	init_rwsem(&ei->i_data_sem);
 	ei->cached_extent.lstart = -1;
 	spin_lock_init(&ei->i_extent_cache_lock);
diff --git a/fs/udf/udf_i.h b/fs/udf/udf_i.h
index 06ff7006b822..312b7c9ef10e 100644
--- a/fs/udf/udf_i.h
+++ b/fs/udf/udf_i.h
@@ -44,7 +44,8 @@ struct udf_inode_info {
 	unsigned		i_use : 1;	/* unallocSpaceEntry */
 	unsigned		i_strat4096 : 1;
 	unsigned		i_streamdir : 1;
-	unsigned		reserved : 25;
+	unsigned		i_hidden : 1;	/* hidden system inode */
+	unsigned		reserved : 24;
 	__u8			*i_data;
 	struct kernel_lb_addr	i_locStreamdir;
 	__u64			i_lenStreams;