linux-kernel - [PATCH RFC 7/9] cachefiles: free content map on invalidate

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Message-Id: <20220802030342.46302-8-jefflexu@linux.alibaba.com>
Date:   Tue,  2 Aug 2022 11:03:40 +0800
From:   Jingbo Xu <jefflexu@...ux.alibaba.com>
To:     dhowells@...hat.com, linux-cachefs@...hat.com
Cc:     linux-kernel@...r.kernel.org, xiang@...nel.org
Subject: [PATCH RFC 7/9] cachefiles: free content map on invalidate

Free the content map when the cached file is invalidated. Also hole
punch the backing content map file if any.

Signed-off-by: Jingbo Xu <jefflexu@...ux.alibaba.com>
---
 fs/cachefiles/content-map.c | 21 +++++++++++++++++++++
 fs/cachefiles/interface.c   |  1 +
 fs/cachefiles/internal.h    |  1 +
 3 files changed, 23 insertions(+)

diff --git a/fs/cachefiles/content-map.c b/fs/cachefiles/content-map.c
index 949ec5d9e4c9..b73a109844ca 100644
--- a/fs/cachefiles/content-map.c
+++ b/fs/cachefiles/content-map.c
@@ -250,3 +250,24 @@ loff_t cachefiles_find_next_hole(struct cachefiles_object *object,
 	return min_t(loff_t, result * CACHEFILES_GRAN_SIZE,
 			     object->cookie->object_size);
 }
+
+void cachefiles_invalidate_content_map(struct cachefiles_object *object)
+{
+	struct file *file = object->volume->content_map[(u8)object->cookie->key_hash];
+
+	if (object->content_info != CACHEFILES_CONTENT_MAP)
+		return;
+
+	write_lock_bh(&object->content_map_lock);
+	free_pages((unsigned long)object->content_map,
+		   get_order(object->content_map_size));
+	object->content_map = NULL;
+	object->content_map_size = 0;
+
+	if (object->content_map_off != CACHEFILES_CONTENT_MAP_OFF_INVAL) {
+		vfs_fallocate(file, FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE,
+				object->content_map_off, object->content_map_size);
+		object->content_map_off = CACHEFILES_CONTENT_MAP_OFF_INVAL;
+	}
+	write_unlock_bh(&object->content_map_lock);
+}
diff --git a/fs/cachefiles/interface.c b/fs/cachefiles/interface.c
index 4cfbdc87b635..f87b9a665d85 100644
--- a/fs/cachefiles/interface.c
+++ b/fs/cachefiles/interface.c
@@ -409,6 +409,7 @@ static bool cachefiles_invalidate_cookie(struct fscache_cookie *cookie)
 
 	old_file = object->file;
 	object->file = new_file;
+	cachefiles_invalidate_content_map(object);
 	object->content_info = CACHEFILES_CONTENT_NO_DATA;
 	set_bit(CACHEFILES_OBJECT_USING_TMPFILE, &object->flags);
 	set_bit(FSCACHE_COOKIE_NEEDS_UPDATE, &object->cookie->flags);
diff --git a/fs/cachefiles/internal.h b/fs/cachefiles/internal.h
index 506700809a6d..c674c4e42529 100644
--- a/fs/cachefiles/internal.h
+++ b/fs/cachefiles/internal.h
@@ -187,6 +187,7 @@ extern loff_t cachefiles_find_next_granule(struct cachefiles_object *object,
 					   loff_t start);
 extern loff_t cachefiles_find_next_hole(struct cachefiles_object *object,
 					loff_t start);
+extern void cachefiles_invalidate_content_map(struct cachefiles_object *object);
 
 /*
  * daemon.c
-- 
2.27.0