Reviewed-by: NeilBrown <neilb@xxxxxxx>
Signed-off-by: Jeff Layton <jlayton@xxxxxxxxxx>
---
fs/libfs.c | 36 ++++++++++++++++++++++++++++++++++++
include/linux/iversion.h | 38 ++------------------------------------
2 files changed, 38 insertions(+), 36 deletions(-)
diff --git a/fs/libfs.c b/fs/libfs.c
index 682d56345a1c..5ae81466a422 100644
--- a/fs/libfs.c
+++ b/fs/libfs.c
@@ -1566,3 +1566,39 @@ bool inode_maybe_inc_iversion(struct inode *inode, bool force)
return true;
}
EXPORT_SYMBOL(inode_maybe_inc_iversion);
+
+/**
+ * inode_query_iversion - read i_version for later use
+ * @inode: inode from which i_version should be read
+ *
+ * Read the inode i_version counter. This should be used by callers that wish
+ * to store the returned i_version for later comparison. This will guarantee
+ * that a later query of the i_version will result in a different value if
+ * anything has changed.
+ *
+ * In this implementation, we fetch the current value, set the QUERIED flag and
+ * then try to swap it into place with a cmpxchg, if it wasn't already set. If
+ * that fails, we try again with the newly fetched value from the cmpxchg.
+ */
+u64 inode_query_iversion(struct inode *inode)
+{
+ u64 cur, new;
+
+ cur = inode_peek_iversion_raw(inode);
+ do {
+ /* If flag is already set, then no need to swap */
+ if (cur & I_VERSION_QUERIED) {
+ /*
+ * This barrier (and the implicit barrier in the
+ * cmpxchg below) pairs with the barrier in
+ * inode_maybe_inc_iversion().
+ */
+ smp_mb();
+ break;
+ }
+
+ new = cur | I_VERSION_QUERIED;
+ } while (!atomic64_try_cmpxchg(&inode->i_version, &cur, new));
+ return cur >> I_VERSION_QUERIED_SHIFT;
+}
+EXPORT_SYMBOL(inode_query_iversion);
diff --git a/include/linux/iversion.h b/include/linux/iversion.h
index e27bd4f55d84..6755d8b4f20b 100644
--- a/include/linux/iversion.h
+++ b/include/linux/iversion.h
@@ -234,42 +234,6 @@ inode_peek_iversion(const struct inode *inode)
return inode_peek_iversion_raw(inode) >> I_VERSION_QUERIED_SHIFT;
}
-/**
- * inode_query_iversion - read i_version for later use
- * @inode: inode from which i_version should be read
- *
- * Read the inode i_version counter. This should be used by callers that wish
- * to store the returned i_version for later comparison. This will guarantee
- * that a later query of the i_version will result in a different value if
- * anything has changed.
- *
- * In this implementation, we fetch the current value, set the QUERIED flag and
- * then try to swap it into place with a cmpxchg, if it wasn't already set. If
- * that fails, we try again with the newly fetched value from the cmpxchg.
- */
-static inline u64
-inode_query_iversion(struct inode *inode)
-{
- u64 cur, new;
-
- cur = inode_peek_iversion_raw(inode);
- do {
- /* If flag is already set, then no need to swap */
- if (cur & I_VERSION_QUERIED) {
- /*
- * This barrier (and the implicit barrier in the
- * cmpxchg below) pairs with the barrier in
- * inode_maybe_inc_iversion().
- */
- smp_mb();
- break;
- }
-
- new = cur | I_VERSION_QUERIED;
- } while (!atomic64_try_cmpxchg(&inode->i_version, &cur, new));
- return cur >> I_VERSION_QUERIED_SHIFT;
-}
-
/*
* For filesystems without any sort of change attribute, the best we can
* do is fake one up from the ctime:
@@ -283,6 +247,8 @@ static inline u64 time_to_chattr(struct timespec64 *t)
return chattr;
}
+u64 inode_query_iversion(struct inode *inode);
+
/**
* inode_eq_iversion_raw - check whether the raw i_version counter has changed
* @inode: inode to check
--
2.37.3
