[PATCH v2 04/14] namei: clean up do_unlinkat retry logic

From: Dmitry Kadashev <dkadashev@gmail.com>
To: Jens Axboe <axboe@kernel.dk>,
	Alexander Viro <viro@zeniv.linux.org.uk>,
	Christian Brauner <christian.brauner@ubuntu.com>,
	Linus Torvalds <torvalds@linux-foundation.org>
Cc: linux-fsdevel@vger.kernel.org, io-uring@vger.kernel.org,
	Dmitry Kadashev <dkadashev@gmail.com>
Subject: [PATCH v2 04/14] namei: clean up do_unlinkat retry logic
Date: Thu, 15 Jul 2021 17:45:26 +0700	[thread overview]
Message-ID: <20210715104536.3598130-5-dkadashev@gmail.com> (raw)
In-Reply-To: <20210715104536.3598130-1-dkadashev@gmail.com>

No functional changes, just move the main logic to a helper function to
make the whole thing easier to follow.

Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Christian Brauner <christian.brauner@ubuntu.com>
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Link: https://lore.kernel.org/io-uring/CAHk-=wh=cpt_tQCirzFZRPawRpbuFTZ2MxNpXiyUF+eBXF=+sw@mail.gmail.com/
Signed-off-by: Dmitry Kadashev <dkadashev@gmail.com>
---
 fs/namei.c | 42 ++++++++++++++++++++++++------------------
 1 file changed, 24 insertions(+), 18 deletions(-)

diff --git a/fs/namei.c b/fs/namei.c
index 6253486718d5..703cce40d597 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -4091,7 +4091,9 @@ EXPORT_SYMBOL(vfs_unlink);
  * writeout happening, and we don't want to prevent access to the directory
  * while waiting on the I/O.
  */
-int do_unlinkat(int dfd, struct filename *name)
+
+static int try_unlinkat(int dfd, struct filename *name,
+			unsigned int lookup_flags)
 {
 	int error;
 	struct dentry *dentry;
@@ -4100,19 +4102,18 @@ int do_unlinkat(int dfd, struct filename *name)
 	int type;
 	struct inode *inode = NULL;
 	struct inode *delegated_inode = NULL;
-	unsigned int lookup_flags = 0;
-retry:
+
 	error = __filename_parentat(dfd, name, lookup_flags, &path, &last, &type);
 	if (error)
-		goto exit1;
+		return error;
 
 	error = -EISDIR;
 	if (type != LAST_NORM)
-		goto exit2;
+		goto exit1;
 
 	error = mnt_want_write(path.mnt);
 	if (error)
-		goto exit2;
+		goto exit1;
 retry_deleg:
 	inode_lock_nested(path.dentry->d_inode, I_MUTEX_PARENT);
 	dentry = __lookup_hash(&last, path.dentry, lookup_flags);
@@ -4129,11 +4130,11 @@ int do_unlinkat(int dfd, struct filename *name)
 		ihold(inode);
 		error = security_path_unlink(&path, dentry);
 		if (error)
-			goto exit3;
+			goto exit2;
 		mnt_userns = mnt_user_ns(path.mnt);
 		error = vfs_unlink(mnt_userns, path.dentry->d_inode, dentry,
 				   &delegated_inode);
-exit3:
+exit2:
 		dput(dentry);
 	}
 	inode_unlock(path.dentry->d_inode);
@@ -4146,17 +4147,9 @@ int do_unlinkat(int dfd, struct filename *name)
 			goto retry_deleg;
 	}
 	mnt_drop_write(path.mnt);
-exit2:
-	path_put(&path);
 exit1:
-	if (unlikely(retry_estale(error, lookup_flags))) {
-		lookup_flags |= LOOKUP_REVAL;
-		inode = NULL;
-		goto retry;
-	}
-	putname(name);
+	path_put(&path);
 	return error;
-
 slashes:
 	if (d_is_negative(dentry))
 		error = -ENOENT;
@@ -4164,7 +4157,20 @@ int do_unlinkat(int dfd, struct filename *name)
 		error = -EISDIR;
 	else
 		error = -ENOTDIR;
-	goto exit3;
+	goto exit2;
+}
+
+int do_unlinkat(int dfd, struct filename *name)
+{
+	int error;
+
+	error = try_unlinkat(dfd, name, 0);
+	if (unlikely(retry_estale(error, 0)))
+		error = try_unlinkat(dfd, name, LOOKUP_REVAL);
+
+	putname(name);
+	return error;
+
 }
 
 SYSCALL_DEFINE3(unlinkat, int, dfd, const char __user *, pathname, int, flag)
-- 
2.30.2

