Merge patch series "re-enable IOCB_NOWAIT writes to files v2"

Christoph Hellwig <hch@lst.de> says:

[Fix] the layering bypass in btrfs when updating timestamps on device
files for devices removed from btrfs usage, and FMODE_NOCMTIME handling
in the VFS now that nfsd started using it.  Note that I'm still not sure
that nfsd usage is fully correct for all file systems, as only XFS
explicitly supports FMODE_NOCMTIME, but at least the generic code does
the right thing now.

* patches from https://patch.msgid.link/20251120064859.2911749-1-hch@lst.de:
  orangefs: use inode_update_timestamps directly
  btrfs: fix the comment on btrfs_update_time
  btrfs: use vfs_utimes to update file timestamps
  fs: export vfs_utimes
  fs: lift the FMODE_NOCMTIME check into file_update_time_flags
  fs: refactor file timestamp update logic

Link: https://patch.msgid.link/20251120064859.2911749-1-hch@lst.de
Signed-off-by: Christian Brauner <brauner@kernel.org>

1 files changed, 19 insertions, 39 deletions

diff --git a/fs/inode.c b/fs/inode.c
index ec9339024ac3..24dab63844db 100644
--- a/fs/inode.c
+++ b/fs/inode.c
@@ -2310,42 +2310,40 @@ 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))
 		return 0;
+	if (unlikely(file->f_mode & FMODE_NOCMTIME))
+		return 0;
 
 	now = current_time(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;
-
-	return sync_it;
-}
+		sync_mode |= S_VERSION;
 
-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 +2363,7 @@ 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 +2385,6 @@ 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 +2393,7 @@ 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);
 }
 
 /**