fs: refactor file timestamp update logic

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>
Link: https://patch.msgid.link/20251120064859.2911749-2-hch@lst.de
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Christian Brauner <brauner@kernel.org>

diff --git a/fs/inode.c b/fs/inode.c
index ec9339024ac36e7ba893f7dcc0f55feb7efd2f91..4884ffa931e7bc3f96a2a1091f33b8f31f279594 100644 (file)
--- a/fs/inode.c
+++ b/fs/inode.c
@@ -2310,10 +2310,12 @@ out:
 }
 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))
@@ -2323,29 +2325,23 @@ 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;
 }
 
@@ -2365,14 +2361,7 @@ 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);
 
@@ -2394,7 +2383,6 @@ 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.
@@ -2403,17 +2391,9 @@ 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);
 }
 
 /**