fs: Introduce DCACHE_DONTCACHE
DCACHE_DONTCACHE indicates a dentry should not be cached on final
dput().
Also add a helper function to mark DCACHE_DONTCACHE on all dentries
pointing to a specific inode when that inode is being set I_DONTCACHE.
This facilitates dropping dentry references to inodes sooner which
require eviction to swap S_DAX mode.
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Ira Weiny <ira.weiny@intel.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
diff --git a/fs/dcache.c b/fs/dcache.c
index b280e07..0d07fb3 100644
--- a/fs/dcache.c
+++ b/fs/dcache.c
@@ -647,6 +647,10 @@ static inline bool retain_dentry(struct dentry *dentry)
if (dentry->d_op->d_delete(dentry))
return false;
}
+
+ if (unlikely(dentry->d_flags & DCACHE_DONTCACHE))
+ return false;
+
/* retain; LRU fodder */
dentry->d_lockref.count--;
if (unlikely(!(dentry->d_flags & DCACHE_LRU_LIST)))
@@ -656,6 +660,21 @@ static inline bool retain_dentry(struct dentry *dentry)
return true;
}
+void d_mark_dontcache(struct inode *inode)
+{
+ struct dentry *de;
+
+ spin_lock(&inode->i_lock);
+ hlist_for_each_entry(de, &inode->i_dentry, d_u.d_alias) {
+ spin_lock(&de->d_lock);
+ de->d_flags |= DCACHE_DONTCACHE;
+ spin_unlock(&de->d_lock);
+ }
+ inode->i_state |= I_DONTCACHE;
+ spin_unlock(&inode->i_lock);
+}
+EXPORT_SYMBOL(d_mark_dontcache);
+
/*
* Finish off a dentry we've decided to kill.
* dentry->d_lock must be held, returns with it unlocked.
