[ Upstream commit 5dc84855b0fc7e1db182b55c5564fd539d6eff92 ]
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 dhowells@redhat.com Signed-off-by: Sasha Levin sashal@kernel.org --- fs/afs/dir.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/fs/afs/dir.c b/fs/afs/dir.c index 855bf2b79fed4..54e7f6f1405e2 100644 --- a/fs/afs/dir.c +++ b/fs/afs/dir.c @@ -937,7 +937,7 @@ 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) @@ -1001,6 +1001,7 @@ 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]");