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| author | Miklos Szeredi <mszeredi@redhat.com> | 2018-11-01 21:31:39 +0100 |
|---|---|---|
| committer | Miklos Szeredi <mszeredi@redhat.com> | 2018-11-01 21:31:39 +0100 |
| commit | d47748e5ae5af6572e520cc9767bbe70c22ea498 (patch) | |
| tree | ae33bdfffaaa6c1e9297d33f39dff2ddee4ddb24 /fs/overlayfs/super.c | |
| parent | 5e1275808630ea3b2c97c776f40e475017535f72 (diff) | |
| download | linux-d47748e5ae5af6572e520cc9767bbe70c22ea498.tar.bz2 | |
ovl: automatically enable redirect_dir on metacopy=on
Current behavior is to automatically disable metacopy if redirect_dir is
not enabled and proceed with the mount.
If "metacopy=on" mount option was given, then this behavior can confuse the
user: no mount failure, yet metacopy is disabled.
This patch makes metacopy=on imply redirect_dir=on.
The converse is also true: turning off full redirect with redirect_dir=
{off|follow|nofollow} will disable metacopy.
If both metacopy=on and redirect_dir={off|follow|nofollow} is specified,
then mount will fail, since there's no way to correctly resolve the
conflict.
Reported-by: Daniel Walsh <dwalsh@redhat.com>
Fixes: d5791044d2e5 ("ovl: Provide a mount option metacopy=on/off...")
Cc: <stable@vger.kernel.org> # v4.19
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Diffstat (limited to 'fs/overlayfs/super.c')
| -rw-r--r-- | fs/overlayfs/super.c | 36 |
1 files changed, 29 insertions, 7 deletions
diff --git a/fs/overlayfs/super.c b/fs/overlayfs/super.c index 22ffb23ea44d..0116735cc321 100644 --- a/fs/overlayfs/super.c +++ b/fs/overlayfs/super.c @@ -472,6 +472,7 @@ static int ovl_parse_opt(char *opt, struct ovl_config *config) { char *p; int err; + bool metacopy_opt = false, redirect_opt = false; config->redirect_mode = kstrdup(ovl_redirect_mode_def(), GFP_KERNEL); if (!config->redirect_mode) @@ -516,6 +517,7 @@ static int ovl_parse_opt(char *opt, struct ovl_config *config) config->redirect_mode = match_strdup(&args[0]); if (!config->redirect_mode) return -ENOMEM; + redirect_opt = true; break; case OPT_INDEX_ON: @@ -548,6 +550,7 @@ static int ovl_parse_opt(char *opt, struct ovl_config *config) case OPT_METACOPY_ON: config->metacopy = true; + metacopy_opt = true; break; case OPT_METACOPY_OFF: @@ -572,13 +575,32 @@ static int ovl_parse_opt(char *opt, struct ovl_config *config) if (err) return err; - /* metacopy feature with upper requires redirect_dir=on */ - if (config->upperdir && config->metacopy && !config->redirect_dir) { - pr_warn("overlayfs: metadata only copy up requires \"redirect_dir=on\", falling back to metacopy=off.\n"); - config->metacopy = false; - } else if (config->metacopy && !config->redirect_follow) { - pr_warn("overlayfs: metadata only copy up requires \"redirect_dir=follow\" on non-upper mount, falling back to metacopy=off.\n"); - config->metacopy = false; + /* + * This is to make the logic below simpler. It doesn't make any other + * difference, since config->redirect_dir is only used for upper. + */ + if (!config->upperdir && config->redirect_follow) + config->redirect_dir = true; + + /* Resolve metacopy -> redirect_dir dependency */ + if (config->metacopy && !config->redirect_dir) { + if (metacopy_opt && redirect_opt) { + pr_err("overlayfs: conflicting options: metacopy=on,redirect_dir=%s\n", + config->redirect_mode); + return -EINVAL; + } + if (redirect_opt) { + /* + * There was an explicit redirect_dir=... that resulted + * in this conflict. + */ + pr_info("overlayfs: disabling metacopy due to redirect_dir=%s\n", + config->redirect_mode); + config->metacopy = false; + } else { + /* Automatically enable redirect otherwise. */ + config->redirect_follow = config->redirect_dir = true; + } } return 0; |