[PATCH 11/16] fs: allow error returns from inode_update_timestamps

[Christoph Hellwig <hch@lst.de>]

Change flags to a by reference argument so that it can be updated so that
the return value can be used for error returns.  This will be used to
implement non-blocking timestamp updates.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 fs/btrfs/inode.c    |  8 +++++---
 fs/inode.c          | 24 ++++++++++++++++--------
 fs/nfs/inode.c      |  4 ++--
 fs/orangefs/inode.c |  5 ++++-
 fs/ubifs/file.c     |  2 +-
 include/linux/fs.h  |  2 +-
 6 files changed, 29 insertions(+), 16 deletions(-)

diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 05f6d272c5d7..668e4a1df7ae 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -6297,13 +6297,15 @@ static int btrfs_dirty_inode(struct btrfs_inode *inode)
 static int btrfs_update_time(struct inode *inode, int flags)
 {
 	struct btrfs_root *root = BTRFS_I(inode)->root;
-	bool dirty;
+	int error;
 
 	if (btrfs_root_readonly(root))
 		return -EROFS;
 
-	dirty = inode_update_timestamps(inode, flags);
-	return dirty ? btrfs_dirty_inode(BTRFS_I(inode)) : 0;
+	error = inode_update_timestamps(inode, &flags);
+	if (error || !flags)
+		return error;
+	return btrfs_dirty_inode(BTRFS_I(inode));
 }
 
 /*
diff --git a/fs/inode.c b/fs/inode.c
index edbc24a489ca..5b338de7a4c6 100644
--- a/fs/inode.c
+++ b/fs/inode.c
@@ -2057,14 +2057,18 @@ static bool relatime_need_update(struct vfsmount *mnt, struct inode *inode,
  * attempt to update all three of them. S_ATIME updates can be handled
  * independently of the rest.
  *
- * Returns a set of S_* flags indicating which values changed.
+ * Updates @flags to contain the S_* flags which actually need changing.  This
+ * can drop flags from the input when they don't need an update, or can add
+ * S_VERSION when the version needs to be bumped.
+ *
+ * Returns 0 or a negative errno.
  */
-int inode_update_timestamps(struct inode *inode, int flags)
+int inode_update_timestamps(struct inode *inode, int *flags)
 {
 	int updated = 0;
 	struct timespec64 now;
 
-	if (flags & (S_MTIME|S_CTIME|S_VERSION)) {
+	if (*flags & (S_MTIME | S_CTIME | S_VERSION)) {
 		struct timespec64 ctime = inode_get_ctime(inode);
 		struct timespec64 mtime = inode_get_mtime(inode);
 
@@ -2081,7 +2085,7 @@ int inode_update_timestamps(struct inode *inode, int flags)
 		now = current_time(inode);
 	}
 
-	if (flags & S_ATIME) {
+	if (*flags & S_ATIME) {
 		struct timespec64 atime = inode_get_atime(inode);
 
 		if (!timespec64_equal(&now, &atime)) {
@@ -2089,7 +2093,9 @@ int inode_update_timestamps(struct inode *inode, int flags)
 			updated |= S_ATIME;
 		}
 	}
-	return updated;
+
+	*flags = updated;
+	return 0;
 }
 EXPORT_SYMBOL(inode_update_timestamps);
 
@@ -2107,10 +2113,12 @@ EXPORT_SYMBOL(inode_update_timestamps);
  */
 int generic_update_time(struct inode *inode, int flags)
 {
-	flags = inode_update_timestamps(inode, flags);
-	if (flags)
+	int error;
+
+	error = inode_update_timestamps(inode, &flags);
+	if (!error && flags)
 		mark_inode_dirty_time(inode, flags);
-	return 0;
+	return error;
 }
 EXPORT_SYMBOL(generic_update_time);
 
diff --git a/fs/nfs/inode.c b/fs/nfs/inode.c
index 13ad70fc00d8..f7d5d23cd927 100644
--- a/fs/nfs/inode.c
+++ b/fs/nfs/inode.c
@@ -671,8 +671,8 @@ static void nfs_set_timestamps_to_ts(struct inode *inode, struct iattr *attr)
 
 static void nfs_update_timestamps(struct inode *inode, unsigned int ia_valid)
 {
-	enum file_time_flags time_flags = 0;
 	unsigned int cache_flags = 0;
+	int time_flags = 0;
 
 	if (ia_valid & ATTR_MTIME) {
 		time_flags |= S_MTIME | S_CTIME;
@@ -682,7 +682,7 @@ static void nfs_update_timestamps(struct inode *inode, unsigned int ia_valid)
 		time_flags |= S_ATIME;
 		cache_flags |= NFS_INO_INVALID_ATIME;
 	}
-	inode_update_timestamps(inode, time_flags);
+	inode_update_timestamps(inode, &time_flags);
 	NFS_I(inode)->cache_validity &= ~cache_flags;
 }
 
diff --git a/fs/orangefs/inode.c b/fs/orangefs/inode.c
index 55f6c8026812..ec56a777053d 100644
--- a/fs/orangefs/inode.c
+++ b/fs/orangefs/inode.c
@@ -875,11 +875,14 @@ int orangefs_permission(struct mnt_idmap *idmap,
 int orangefs_update_time(struct inode *inode, int flags)
 {
 	struct iattr iattr;
+	int error;
 
 	gossip_debug(GOSSIP_INODE_DEBUG, "orangefs_update_time: %pU\n",
 	    get_khandle_from_ino(inode));
 
-	flags = inode_update_timestamps(inode, flags);
+	error = inode_update_timestamps(inode, &flags);
+	if (error || !flags)
+		return error;
 
 	memset(&iattr, 0, sizeof iattr);
         if (flags & S_ATIME)
diff --git a/fs/ubifs/file.c b/fs/ubifs/file.c
index 3e119cb93ea9..7f631473da6c 100644
--- a/fs/ubifs/file.c
+++ b/fs/ubifs/file.c
@@ -1387,7 +1387,7 @@ int ubifs_update_time(struct inode *inode, int flags)
 		return err;
 
 	mutex_lock(&ui->ui_mutex);
-	inode_update_timestamps(inode, flags);
+	inode_update_timestamps(inode, &flags);
 	release = ui->dirty;
 	__mark_inode_dirty(inode, I_DIRTY_SYNC);
 	mutex_unlock(&ui->ui_mutex);
diff --git a/include/linux/fs.h b/include/linux/fs.h
index b4d82e5c6c32..a6a38e30c998 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -2825,7 +2825,7 @@ extern int current_umask(void);
 extern void ihold(struct inode * inode);
 extern void iput(struct inode *);
 void iput_not_last(struct inode *);
-int inode_update_timestamps(struct inode *inode, int flags);
+int inode_update_timestamps(struct inode *inode, int *flags);
 int generic_update_time(struct inode *inode, int flags);
 
 /* /sys/fs */
-- 
2.47.3