From 590fb51f1cf99c4a48a3b1bd65885192e877b561 Mon Sep 17 00:00:00 2001 From: "Yan, Zheng" Date: Tue, 13 Aug 2013 15:42:02 +0800 Subject: [PATCH] vfs: call d_op->d_prune() before unhashing dentry The d_prune dentry operation is used to notify filesystem when VFS about to prune a hashed dentry from the dcache. There are three code paths that prune dentries: shrink_dcache_for_umount_subtree(), prune_dcache_sb() and d_prune_aliases(). For the d_prune_aliases() case, VFS unhashes the dentry first, then call the d_prune dentry operation. This confuses ceph_d_prune() (ceph uses the d_prune dentry operation to maintain a flag indicating whether the complete contents of a directory are in the dcache, pruning unhashed dentry does not affect dir's completeness) This patch fixes the issue by calling the d_prune dentry operation in d_prune_aliases(), before unhashing the dentry. Also make VFS only call the d_prune dentry operation for hashed dentry, to avoid calling the d_prune dentry operation twice when dentry is pruned by d_prune_aliases(). Signed-off-by: Yan, Zheng Signed-off-by: Al Viro --- fs/dcache.c | 13 +++++++++++-- 1 file changed, 11 insertions(+), 2 deletions(-) diff --git a/fs/dcache.c b/fs/dcache.c index 83cfb834db03..2e5f9ca83285 100644 --- a/fs/dcache.c +++ b/fs/dcache.c @@ -472,7 +472,7 @@ relock: * inform the fs via d_prune that this dentry is about to be * unhashed and destroyed. */ - if (dentry->d_flags & DCACHE_OP_PRUNE) + if ((dentry->d_flags & DCACHE_OP_PRUNE) && !d_unhashed(dentry)) dentry->d_op->d_prune(dentry); dentry_lru_del(dentry); @@ -719,6 +719,14 @@ restart: hlist_for_each_entry(dentry, &inode->i_dentry, d_alias) { spin_lock(&dentry->d_lock); if (!dentry->d_count) { + /* + * inform the fs via d_prune that this dentry + * is about to be unhashed and destroyed. + */ + if ((dentry->d_flags & DCACHE_OP_PRUNE) && + !d_unhashed(dentry)) + dentry->d_op->d_prune(dentry); + __dget_dlock(dentry); __d_drop(dentry); spin_unlock(&dentry->d_lock); @@ -907,7 +915,8 @@ static void shrink_dcache_for_umount_subtree(struct dentry *dentry) * inform the fs that this dentry is about to be * unhashed and destroyed. */ - if (dentry->d_flags & DCACHE_OP_PRUNE) + if ((dentry->d_flags & DCACHE_OP_PRUNE) && + !d_unhashed(dentry)) dentry->d_op->d_prune(dentry); dentry_lru_del(dentry); -- 2.20.1