From 773783681d87185e553b0a145e67e64d7967f0ce Mon Sep 17 00:00:00 2001 From: Miklos Szeredi Date: Wed, 28 Feb 2024 16:50:49 +0100 Subject: [PATCH] fuse: fix root lookup with nonzero generation [ Upstream commit 68ca1b49e430f6534d0774a94147a823e3b8b26e ] The root inode has a fixed nodeid and generation (1, 0). Prior to the commit 15db16837a35 ("fuse: fix illegal access to inode with reused nodeid") generation number on lookup was ignored. After this commit lookup with the wrong generation number resulted in the inode being unhashed. This is correct for non-root inodes, but replacing the root inode is wrong and results in weird behavior. Fix by reverting to the old behavior if ignoring the generation for the root inode, but issuing a warning in dmesg. Reported-by: Antonio SJ Musumeci Closes: https://lore.kernel.org/all/CAOQ4uxhek5ytdN8Yz2tNEOg5ea4NkBb4nk0FGPjPk_9nz-VG3g@mail.gmail.com/ Fixes: 15db16837a35 ("fuse: fix illegal access to inode with reused nodeid") Cc: # v5.14 Signed-off-by: Miklos Szeredi Signed-off-by: Sasha Levin --- fs/fuse/dir.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/fs/fuse/dir.c b/fs/fuse/dir.c index 4ea52906ae15..44d1c8cc58a4 100644 --- a/fs/fuse/dir.c +++ b/fs/fuse/dir.c @@ -390,6 +390,10 @@ int fuse_lookup_name(struct super_block *sb, u64 nodeid, const struct qstr *name goto out_put_forget; if (fuse_invalid_attr(&outarg->attr)) goto out_put_forget; + if (outarg->nodeid == FUSE_ROOT_ID && outarg->generation != 0) { + pr_warn_once("root generation should be zero\n"); + outarg->generation = 0; + } *inode = fuse_iget(sb, outarg->nodeid, outarg->generation, &outarg->attr, entry_attr_timeout(outarg),