From: Darrick J. Wong <djwong@xxxxxxxxxx>
Move the directory entry update hook code to xfs_dir2 so that it is
mostly consolidated with the higher level directory functions. Retain
the exports so that online fsck can still send notifications through the
hooks.
Signed-off-by: Darrick J. Wong <djwong@xxxxxxxxxx>
---
libxfs/xfs_dir2.c | 125 +++++++++++++++++++++++++++++++++++++++++++++++++++--
libxfs/xfs_dir2.h | 24 ++++++++++
2 files changed, 144 insertions(+), 5 deletions(-)
diff --git a/libxfs/xfs_dir2.c b/libxfs/xfs_dir2.c
index 7a1d55dff69..bfdbcc3cd3e 100644
--- a/libxfs/xfs_dir2.c
+++ b/libxfs/xfs_dir2.c
@@ -788,6 +788,72 @@ xfs_dir2_compname(
return xfs_da_compname(args, name, len);
}
+#ifdef CONFIG_XFS_LIVE_HOOKS
+/*
+ * Use a static key here to reduce the overhead of directory live update hooks.
+ * If the compiler supports jump labels, the static branch will be replaced by
+ * a nop sled when there are no hook users. Online fsck is currently the only
+ * caller, so this is a reasonable tradeoff.
+ *
+ * Note: Patching the kernel code requires taking the cpu hotplug lock. Other
+ * parts of the kernel allocate memory with that lock held, which means that
+ * XFS callers cannot hold any locks that might be used by memory reclaim or
+ * writeback when calling the static_branch_{inc,dec} functions.
+ */
+DEFINE_STATIC_XFS_HOOK_SWITCH(xfs_dir_hooks_switch);
+
+void
+xfs_dir_hook_disable(void)
+{
+ xfs_hooks_switch_off(&xfs_dir_hooks_switch);
+}
+
+void
+xfs_dir_hook_enable(void)
+{
+ xfs_hooks_switch_on(&xfs_dir_hooks_switch);
+}
+
+/* Call hooks for a directory update relating to a child dirent update. */
+inline void
+xfs_dir_update_hook(
+ struct xfs_inode *dp,
+ struct xfs_inode *ip,
+ int delta,
+ const struct xfs_name *name)
+{
+ if (xfs_hooks_switched_on(&xfs_dir_hooks_switch)) {
+ struct xfs_dir_update_params p = {
+ .dp = dp,
+ .ip = ip,
+ .delta = delta,
+ .name = name,
+ };
+ struct xfs_mount *mp = ip->i_mount;
+
+ xfs_hooks_call(&mp->m_dir_update_hooks, 0, &p);
+ }
+}
+
+/* Call the specified function during a directory update. */
+int
+xfs_dir_hook_add(
+ struct xfs_mount *mp,
+ struct xfs_dir_hook *hook)
+{
+ return xfs_hooks_add(&mp->m_dir_update_hooks, &hook->dirent_hook);
+}
+
+/* Stop calling the specified function during a directory update. */
+void
+xfs_dir_hook_del(
+ struct xfs_mount *mp,
+ struct xfs_dir_hook *hook)
+{
+ xfs_hooks_del(&mp->m_dir_update_hooks, &hook->dirent_hook);
+}
+#endif /* CONFIG_XFS_LIVE_HOOKS */
+
/*
* Given a directory @dp, a newly allocated inode @ip, and a @name, link @ip
* into @dp under the given @name. If @ip is a directory, it will be
@@ -829,7 +895,12 @@ xfs_dir_create_child(
* If we have parent pointers, we need to add the attribute containing
* the parent information now.
*/
- return xfs_parent_add(tp, du->ppargs, dp, name, ip);
+ error = xfs_parent_add(tp, du->ppargs, dp, name, ip);
+ if (error)
+ return error;
+
+ xfs_dir_update_hook(dp, ip, 1, name);
+ return 0;
}
/*
@@ -887,7 +958,12 @@ xfs_dir_add_child(
* attribute, we need to create it correctly, otherwise we can just add
* the parent to the inode.
*/
- return xfs_parent_add(tp, du->ppargs, dp, name, ip);
+ error = xfs_parent_add(tp, du->ppargs, dp, name, ip);
+ if (error)
+ return error;
+
+ xfs_dir_update_hook(dp, ip, 1, name);
+ return 0;
}
/*
@@ -962,7 +1038,12 @@ xfs_dir_remove_child(
}
/* Remove parent pointer. */
- return xfs_parent_remove(tp, du->ppargs, dp, name, ip);
+ error = xfs_parent_remove(tp, du->ppargs, dp, name, ip);
+ if (error)
+ return error;
+
+ xfs_dir_update_hook(dp, ip, -1, name);
+ return 0;
}
/*
@@ -1078,8 +1159,24 @@ xfs_dir_exchange_children(
if (error)
return error;
- return xfs_parent_replace(tp, du2->ppargs, dp2, name2, dp1, name1,
+ error = xfs_parent_replace(tp, du2->ppargs, dp2, name2, dp1, name1,
ip2);
+ if (error)
+ return error;
+
+ /*
+ * Inform our hook clients that we've finished an exchange operation as
+ * follows: removed the source and target files from their directories;
+ * added the target to the source directory; and added the source to
+ * the target directory. All inodes are locked, so it's ok to model a
+ * rename this way so long as we say we deleted entries before we add
+ * new ones.
+ */
+ xfs_dir_update_hook(dp1, ip1, -1, name1);
+ xfs_dir_update_hook(dp2, ip2, -1, name2);
+ xfs_dir_update_hook(dp1, ip2, 1, name1);
+ xfs_dir_update_hook(dp2, ip1, 1, name2);
+ return 0;
}
/*
@@ -1294,6 +1391,24 @@ xfs_dir_rename_children(
if (error)
return error;
- return xfs_parent_remove(tp, du_tgt->ppargs, target_dp, target_name,
+ error = xfs_parent_remove(tp, du_tgt->ppargs, target_dp, target_name,
target_ip);
+ if (error)
+ return error;
+
+ /*
+ * Inform our hook clients that we've finished a rename operation as
+ * follows: removed the source and target files from their directories;
+ * that we've added the source to the target directory; and finally
+ * that we've added the whiteout, if there was one. All inodes are
+ * locked, so it's ok to model a rename this way so long as we say we
+ * deleted entries before we add new ones.
+ */
+ if (target_ip)
+ xfs_dir_update_hook(target_dp, target_ip, -1, target_name);
+ xfs_dir_update_hook(src_dp, src_ip, -1, src_name);
+ xfs_dir_update_hook(target_dp, src_ip, 1, target_name);
+ if (du_wip->ip)
+ xfs_dir_update_hook(src_dp, du_wip->ip, 1, src_name);
+ return 0;
}
diff --git a/libxfs/xfs_dir2.h b/libxfs/xfs_dir2.h
index 5e8b18f3f00..57b124abb17 100644
--- a/libxfs/xfs_dir2.h
+++ b/libxfs/xfs_dir2.h
@@ -293,6 +293,30 @@ static inline unsigned char xfs_ascii_ci_xfrm(unsigned char c)
return c;
}
+struct xfs_dir_update_params {
+ const struct xfs_inode *dp;
+ const struct xfs_inode *ip;
+ const struct xfs_name *name;
+ int delta;
+};
+
+#ifdef CONFIG_XFS_LIVE_HOOKS
+void xfs_dir_update_hook(struct xfs_inode *dp, struct xfs_inode *ip,
+ int delta, const struct xfs_name *name);
+
+struct xfs_dir_hook {
+ struct xfs_hook dirent_hook;
+};
+
+void xfs_dir_hook_disable(void);
+void xfs_dir_hook_enable(void);
+
+int xfs_dir_hook_add(struct xfs_mount *mp, struct xfs_dir_hook *hook);
+void xfs_dir_hook_del(struct xfs_mount *mp, struct xfs_dir_hook *hook);
+#else
+# define xfs_dir_update_hook(dp, ip, delta, name) ((void)0)
+#endif /* CONFIG_XFS_LIVE_HOOKS */
+
struct xfs_parent_args;
struct xfs_dir_update {
