[PATCH 01/16] fs: refactor file timestamp update logic

[Christoph Hellwig <hch@lst.de>]

Currently the two high-level APIs use two helper functions to implement
almost all of the logic.  Refactor the two helpers and the common logic
into a new file_update_time_flags routine that gets the iocb flags or
0 in case of file_update_time passed so that the entire logic is
contained in a single function and can be easily understood and modified.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
---
 fs/inode.c | 54 +++++++++++++++++-------------------------------------
 1 file changed, 17 insertions(+), 37 deletions(-)

diff --git a/fs/inode.c b/fs/inode.c
index cff1d3af0d57..540f4a28c202 100644
--- a/fs/inode.c
+++ b/fs/inode.c
@@ -2322,10 +2322,12 @@ struct timespec64 current_time(struct inode *inode)
 }
 EXPORT_SYMBOL(current_time);
 
-static int inode_needs_update_time(struct inode *inode)
+static int file_update_time_flags(struct file *file, unsigned int flags)
 {
+	struct inode *inode = file_inode(file);
 	struct timespec64 now, ts;
-	int sync_it = 0;
+	int sync_mode = 0;
+	int ret = 0;
 
 	/* First try to exhaust all avenues to not sync */
 	if (IS_NOCMTIME(inode))
@@ -2335,29 +2337,23 @@ static int inode_needs_update_time(struct inode *inode)
 
 	ts = inode_get_mtime(inode);
 	if (!timespec64_equal(&ts, &now))
-		sync_it |= S_MTIME;
-
+		sync_mode |= S_MTIME;
 	ts = inode_get_ctime(inode);
 	if (!timespec64_equal(&ts, &now))
-		sync_it |= S_CTIME;
-
+		sync_mode |= S_CTIME;
 	if (IS_I_VERSION(inode) && inode_iversion_need_inc(inode))
-		sync_it |= S_VERSION;
+		sync_mode |= S_VERSION;
 
-	return sync_it;
-}
-
-static int __file_update_time(struct file *file, int sync_mode)
-{
-	int ret = 0;
-	struct inode *inode = file_inode(file);
+	if (!sync_mode)
+		return 0;
 
-	/* try to update time settings */
-	if (!mnt_get_write_access_file(file)) {
-		ret = inode_update_time(inode, sync_mode);
-		mnt_put_write_access_file(file);
-	}
+	if (flags & IOCB_NOWAIT)
+		return -EAGAIN;
 
+	if (mnt_get_write_access_file(file))
+		return 0;
+	ret = inode_update_time(inode, sync_mode);
+	mnt_put_write_access_file(file);
 	return ret;
 }
 
@@ -2377,14 +2373,7 @@ static int __file_update_time(struct file *file, int sync_mode)
  */
 int file_update_time(struct file *file)
 {
-	int ret;
-	struct inode *inode = file_inode(file);
-
-	ret = inode_needs_update_time(inode);
-	if (ret <= 0)
-		return ret;
-
-	return __file_update_time(file, ret);
+	return file_update_time_flags(file, 0);
 }
 EXPORT_SYMBOL(file_update_time);
 
@@ -2406,7 +2395,6 @@ EXPORT_SYMBOL(file_update_time);
 static int file_modified_flags(struct file *file, int flags)
 {
 	int ret;
-	struct inode *inode = file_inode(file);
 
 	/*
 	 * Clear the security bits if the process is not being run by root.
@@ -2415,17 +2403,9 @@ static int file_modified_flags(struct file *file, int flags)
 	ret = file_remove_privs_flags(file, flags);
 	if (ret)
 		return ret;
-
 	if (unlikely(file->f_mode & FMODE_NOCMTIME))
 		return 0;
-
-	ret = inode_needs_update_time(inode);
-	if (ret <= 0)
-		return ret;
-	if (flags & IOCB_NOWAIT)
-		return -EAGAIN;
-
-	return __file_update_time(file, ret);
+	return file_update_time_flags(file, flags);
 }
 
 /**
-- 
2.47.3