sunrpc: add a new cache_detail operation for when a cache is flushed

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>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
This commit is contained in:
Jeff Layton 2019-08-18 14:18:44 -04:00 committed by J. Bruce Fields
parent 4866073e6d
commit f69d6d8eef
2 changed files with 4 additions and 0 deletions

View File

@ -87,6 +87,7 @@ 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);

View File

@ -1524,6 +1524,9 @@ static ssize_t write_flush(struct file *file, const char __user *buf,
cd->nextcheck = now;
cache_flush();
if (cd->flush)
cd->flush();
*ppos += count;
return count;
}