2022-09-02 10:38:59

by Shiyang Ruan

[permalink] [raw]
Subject: [PATCH 2/3] fs: move drop_pagecache_sb() for others to use

xfs_notify_failure requires a method to invalidate all mappings.
drop_pagecache_sb() can do this but it is a static function and only
build with CONFIG_SYSCTL. Now, move it to super.c and make it available
for others.

Signed-off-by: Shiyang Ruan <[email protected]>
---
fs/drop_caches.c | 33 ---------------------------------
fs/super.c | 34 ++++++++++++++++++++++++++++++++++
include/linux/fs.h | 1 +
3 files changed, 35 insertions(+), 33 deletions(-)

diff --git a/fs/drop_caches.c b/fs/drop_caches.c
index e619c31b6bd9..5c8406076f9b 100644
--- a/fs/drop_caches.c
+++ b/fs/drop_caches.c
@@ -3,7 +3,6 @@
* Implement the manual drop-all-pagecache function
*/

-#include <linux/pagemap.h>
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/fs.h>
@@ -15,38 +14,6 @@
/* A global variable is a bit ugly, but it keeps the code simple */
int sysctl_drop_caches;

-static void drop_pagecache_sb(struct super_block *sb, void *unused)
-{
- struct inode *inode, *toput_inode = NULL;
-
- spin_lock(&sb->s_inode_list_lock);
- list_for_each_entry(inode, &sb->s_inodes, i_sb_list) {
- spin_lock(&inode->i_lock);
- /*
- * We must skip inodes in unusual state. We may also skip
- * inodes without pages but we deliberately won't in case
- * we need to reschedule to avoid softlockups.
- */
- if ((inode->i_state & (I_FREEING|I_WILL_FREE|I_NEW)) ||
- (mapping_empty(inode->i_mapping) && !need_resched())) {
- spin_unlock(&inode->i_lock);
- continue;
- }
- __iget(inode);
- spin_unlock(&inode->i_lock);
- spin_unlock(&sb->s_inode_list_lock);
-
- invalidate_mapping_pages(inode->i_mapping, 0, -1);
- iput(toput_inode);
- toput_inode = inode;
-
- cond_resched();
- spin_lock(&sb->s_inode_list_lock);
- }
- spin_unlock(&sb->s_inode_list_lock);
- iput(toput_inode);
-}
-
int drop_caches_sysctl_handler(struct ctl_table *table, int write,
void *buffer, size_t *length, loff_t *ppos)
{
diff --git a/fs/super.c b/fs/super.c
index 734ed584a946..bdf53dbe834c 100644
--- a/fs/super.c
+++ b/fs/super.c
@@ -36,6 +36,7 @@
#include <linux/lockdep.h>
#include <linux/user_namespace.h>
#include <linux/fs_context.h>
+#include <linux/pagemap.h>
#include <uapi/linux/mount.h>
#include "internal.h"

@@ -677,6 +678,39 @@ void drop_super_exclusive(struct super_block *sb)
}
EXPORT_SYMBOL(drop_super_exclusive);

+void drop_pagecache_sb(struct super_block *sb, void *unused)
+{
+ struct inode *inode, *toput_inode = NULL;
+
+ spin_lock(&sb->s_inode_list_lock);
+ list_for_each_entry(inode, &sb->s_inodes, i_sb_list) {
+ spin_lock(&inode->i_lock);
+ /*
+ * We must skip inodes in unusual state. We may also skip
+ * inodes without pages but we deliberately won't in case
+ * we need to reschedule to avoid softlockups.
+ */
+ if ((inode->i_state & (I_FREEING|I_WILL_FREE|I_NEW)) ||
+ (mapping_empty(inode->i_mapping) && !need_resched())) {
+ spin_unlock(&inode->i_lock);
+ continue;
+ }
+ __iget(inode);
+ spin_unlock(&inode->i_lock);
+ spin_unlock(&sb->s_inode_list_lock);
+
+ invalidate_mapping_pages(inode->i_mapping, 0, -1);
+ iput(toput_inode);
+ toput_inode = inode;
+
+ cond_resched();
+ spin_lock(&sb->s_inode_list_lock);
+ }
+ spin_unlock(&sb->s_inode_list_lock);
+ iput(toput_inode);
+}
+EXPORT_SYMBOL(drop_pagecache_sb);
+
static void __iterate_supers(void (*f)(struct super_block *))
{
struct super_block *sb, *p = NULL;
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 9eced4cc286e..5ded28c0d2c9 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -3292,6 +3292,7 @@ extern struct super_block *get_super(struct block_device *);
extern struct super_block *get_active_super(struct block_device *bdev);
extern void drop_super(struct super_block *sb);
extern void drop_super_exclusive(struct super_block *sb);
+void drop_pagecache_sb(struct super_block *sb, void *unused);
extern void iterate_supers(void (*)(struct super_block *, void *), void *);
extern void iterate_supers_type(struct file_system_type *,
void (*)(struct super_block *, void *), void *);
--
2.37.2


2022-09-14 19:13:02

by Darrick J. Wong

[permalink] [raw]
Subject: Re: [PATCH 2/3] fs: move drop_pagecache_sb() for others to use

On Fri, Sep 02, 2022 at 10:36:00AM +0000, Shiyang Ruan wrote:
> xfs_notify_failure requires a method to invalidate all mappings.
> drop_pagecache_sb() can do this but it is a static function and only
> build with CONFIG_SYSCTL. Now, move it to super.c and make it available
> for others.
>
> Signed-off-by: Shiyang Ruan <[email protected]>
> ---
> fs/drop_caches.c | 33 ---------------------------------
> fs/super.c | 34 ++++++++++++++++++++++++++++++++++
> include/linux/fs.h | 1 +
> 3 files changed, 35 insertions(+), 33 deletions(-)
>
> diff --git a/fs/drop_caches.c b/fs/drop_caches.c
> index e619c31b6bd9..5c8406076f9b 100644
> --- a/fs/drop_caches.c
> +++ b/fs/drop_caches.c
> @@ -3,7 +3,6 @@
> * Implement the manual drop-all-pagecache function
> */
>
> -#include <linux/pagemap.h>
> #include <linux/kernel.h>
> #include <linux/mm.h>
> #include <linux/fs.h>
> @@ -15,38 +14,6 @@
> /* A global variable is a bit ugly, but it keeps the code simple */
> int sysctl_drop_caches;
>
> -static void drop_pagecache_sb(struct super_block *sb, void *unused)
> -{
> - struct inode *inode, *toput_inode = NULL;
> -
> - spin_lock(&sb->s_inode_list_lock);
> - list_for_each_entry(inode, &sb->s_inodes, i_sb_list) {
> - spin_lock(&inode->i_lock);
> - /*
> - * We must skip inodes in unusual state. We may also skip
> - * inodes without pages but we deliberately won't in case
> - * we need to reschedule to avoid softlockups.
> - */
> - if ((inode->i_state & (I_FREEING|I_WILL_FREE|I_NEW)) ||
> - (mapping_empty(inode->i_mapping) && !need_resched())) {
> - spin_unlock(&inode->i_lock);
> - continue;
> - }
> - __iget(inode);
> - spin_unlock(&inode->i_lock);
> - spin_unlock(&sb->s_inode_list_lock);
> -
> - invalidate_mapping_pages(inode->i_mapping, 0, -1);
> - iput(toput_inode);
> - toput_inode = inode;
> -
> - cond_resched();
> - spin_lock(&sb->s_inode_list_lock);
> - }
> - spin_unlock(&sb->s_inode_list_lock);
> - iput(toput_inode);
> -}
> -
> int drop_caches_sysctl_handler(struct ctl_table *table, int write,
> void *buffer, size_t *length, loff_t *ppos)
> {
> diff --git a/fs/super.c b/fs/super.c
> index 734ed584a946..bdf53dbe834c 100644
> --- a/fs/super.c
> +++ b/fs/super.c
> @@ -36,6 +36,7 @@
> #include <linux/lockdep.h>
> #include <linux/user_namespace.h>
> #include <linux/fs_context.h>
> +#include <linux/pagemap.h>
> #include <uapi/linux/mount.h>
> #include "internal.h"
>
> @@ -677,6 +678,39 @@ void drop_super_exclusive(struct super_block *sb)
> }
> EXPORT_SYMBOL(drop_super_exclusive);
>
> +void drop_pagecache_sb(struct super_block *sb, void *unused)
> +{
> + struct inode *inode, *toput_inode = NULL;
> +
> + spin_lock(&sb->s_inode_list_lock);
> + list_for_each_entry(inode, &sb->s_inodes, i_sb_list) {
> + spin_lock(&inode->i_lock);
> + /*
> + * We must skip inodes in unusual state. We may also skip
> + * inodes without pages but we deliberately won't in case
> + * we need to reschedule to avoid softlockups.
> + */
> + if ((inode->i_state & (I_FREEING|I_WILL_FREE|I_NEW)) ||
> + (mapping_empty(inode->i_mapping) && !need_resched())) {
> + spin_unlock(&inode->i_lock);
> + continue;
> + }
> + __iget(inode);
> + spin_unlock(&inode->i_lock);
> + spin_unlock(&sb->s_inode_list_lock);
> +
> + invalidate_mapping_pages(inode->i_mapping, 0, -1);
> + iput(toput_inode);
> + toput_inode = inode;
> +
> + cond_resched();
> + spin_lock(&sb->s_inode_list_lock);
> + }
> + spin_unlock(&sb->s_inode_list_lock);
> + iput(toput_inode);
> +}
> +EXPORT_SYMBOL(drop_pagecache_sb);

You might want to rename this "super_drop_pagecache" to fit with the
other functions that all have "super" in the name somewhere.

--D

> +
> static void __iterate_supers(void (*f)(struct super_block *))
> {
> struct super_block *sb, *p = NULL;
> diff --git a/include/linux/fs.h b/include/linux/fs.h
> index 9eced4cc286e..5ded28c0d2c9 100644
> --- a/include/linux/fs.h
> +++ b/include/linux/fs.h
> @@ -3292,6 +3292,7 @@ extern struct super_block *get_super(struct block_device *);
> extern struct super_block *get_active_super(struct block_device *bdev);
> extern void drop_super(struct super_block *sb);
> extern void drop_super_exclusive(struct super_block *sb);
> +void drop_pagecache_sb(struct super_block *sb, void *unused);
> extern void iterate_supers(void (*)(struct super_block *, void *), void *);
> extern void iterate_supers_type(struct file_system_type *,
> void (*)(struct super_block *, void *), void *);
> --
> 2.37.2
>