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| author | Amir Goldstein <amir73il@gmail.com> | 2023-06-26 15:34:25 +0200 |
|---|---|---|
| committer | Amir Goldstein <amir73il@gmail.com> | 2023-08-12 18:02:50 +0200 |
| commit | b0504bfe1b8acdcfb5ef466581d930835ef3c49e (patch) | |
| tree | 69074291700ec64db7789139faca31b5f5d05f58 /fs/overlayfs/namei.c | |
| parent | ovl: support encoding non-decodable file handles (diff) | |
| download | linux-b0504bfe1b8acdcfb5ef466581d930835ef3c49e.tar.xz linux-b0504bfe1b8acdcfb5ef466581d930835ef3c49e.zip | |
ovl: add support for unique fsid per instance
The legacy behavior of ovl_statfs() reports the f_fsid filled by
underlying upper fs. This fsid is not unique among overlayfs instances
on the same upper fs.
With mount option uuid=on, generate a non-persistent uuid per overlayfs
instance and use it as the seed for f_fsid, similar to tmpfs.
This is useful for reporting fanotify events with fid info from different
instances of overlayfs over the same upper fs.
The old behavior of null uuid and upper fs fsid is retained with the
mount option uuid=null, which is the default.
The mount option uuid=off that disables uuid checks in underlying layers
also retains the legacy behavior.
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Diffstat (limited to 'fs/overlayfs/namei.c')
| -rw-r--r-- | fs/overlayfs/namei.c | 5 |
1 files changed, 3 insertions, 2 deletions
diff --git a/fs/overlayfs/namei.c b/fs/overlayfs/namei.c index d00ec43f2376..84c06512fb71 100644 --- a/fs/overlayfs/namei.c +++ b/fs/overlayfs/namei.c @@ -171,8 +171,9 @@ struct dentry *ovl_decode_real_fh(struct ovl_fs *ofs, struct ovl_fh *fh, * layer where file handle will be decoded. * In case of uuid=off option just make sure that stored uuid is null. */ - if (ofs->config.uuid ? !uuid_equal(&fh->fb.uuid, &mnt->mnt_sb->s_uuid) : - !uuid_is_null(&fh->fb.uuid)) + if (ovl_origin_uuid(ofs) ? + !uuid_equal(&fh->fb.uuid, &mnt->mnt_sb->s_uuid) : + !uuid_is_null(&fh->fb.uuid)) return NULL; bytes = (fh->fb.len - offsetof(struct ovl_fb, fid)); |