[PATCH v5 09/20] sunrpc: add a new cache_detail operation for when a cache is flushed

Jeff Layton
2015-10-05T11:02:58Z

When the exports table is changed, exportfs will usually write a new
time to the "flush" file in the nfsd.export cache procfile. This tells
the kernel to flush any entries that are older than that value.

This gives us a mechanism to tell whether an unexport might have
occurred. Add a new ->flush cache_detail operation that is called after
flushing the cache whenever someone writes to a "flush" file.

Signed-off-by: Jeff Layton <jeff.layton@primarydata.com>
---
include/linux/sunrpc/cache.h | 1 +
net/sunrpc/cache.c | 3 +++
2 files changed, 4 insertions(+)

diff --git a/include/linux/sunrpc/cache.h b/include/linux/sunrpc/cache.h
index 03d3b4c92d9f..d1c10a978bb2 100644
--- a/include/linux/sunrpc/cache.h
+++ b/include/linux/sunrpc/cache.h
@@ -98,6 +98,7 @@ struct cache_detail {
int has_died);

struct cache_head * (*alloc)(void);
+ void (*flush)(void);
int (*match)(struct cache_head *orig, struct cache_head *new);
void (*init)(struct cache_head *orig, struct cache_head *new);
void (*update)(struct cache_head *orig, struct cache_head *new);
diff --git a/net/sunrpc/cache.c b/net/sunrpc/cache.c
index 4a2340a54401..60da9aa2bdc5 100644
--- a/net/sunrpc/cache.c
+++ b/net/sunrpc/cache.c
@@ -1451,6 +1451,9 @@ static ssize_t write_flush(struct file *file, const char __user *buf,
cd->nextcheck = seconds_since_boot();
cache_flush();

+ if (cd->flush)
+ cd->flush();
+
*ppos += count;
return count;
}
--
2.4.3