From 5dc84855b0fc7e1db182b55c5564fd539d6eff92 Mon Sep 17 00:00:00 2001 From: David Howells Date: Tue, 30 Jul 2019 14:38:51 +0100 Subject: afs: Only update d_fsdata if different in afs_d_revalidate() In the in-kernel afs filesystem, d_fsdata is set with the data version of the parent directory. afs_d_revalidate() will update this to the current directory version, but it shouldn't do this if it the value it read from d_fsdata is the same as no lock is held and cmpxchg() is not used. Fix the code to only change the value if it is different from the current directory version. Fixes: 260a980317da ("[AFS]: Add "directory write" support.") Signed-off-by: David Howells --- fs/afs/dir.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'fs') diff --git a/fs/afs/dir.c b/fs/afs/dir.c index 20aa18b38a49..618e26cea887 100644 --- a/fs/afs/dir.c +++ b/fs/afs/dir.c @@ -1017,7 +1017,7 @@ static int afs_d_revalidate(struct dentry *dentry, unsigned int flags) dir_version = (long)dir->status.data_version; de_version = (long)dentry->d_fsdata; if (de_version == dir_version) - goto out_valid; + goto out_valid_noupdate; dir_version = (long)dir->invalid_before; if (de_version - dir_version >= 0) @@ -1081,6 +1081,7 @@ static int afs_d_revalidate(struct dentry *dentry, unsigned int flags) out_valid: dentry->d_fsdata = (void *)dir_version; +out_valid_noupdate: dput(parent); key_put(key); _leave(" = 1 [valid]"); -- cgit v1.2.3-55-g7522