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path: root/fs/overlayfs/super.c
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Diffstat (limited to 'fs/overlayfs/super.c')
-rw-r--r--fs/overlayfs/super.c73
1 files changed, 49 insertions, 24 deletions
diff --git a/fs/overlayfs/super.c b/fs/overlayfs/super.c
index 91476bc422f9..4b38141c2985 100644
--- a/fs/overlayfs/super.c
+++ b/fs/overlayfs/super.c
@@ -580,12 +580,19 @@ static int ovl_parse_opt(char *opt, struct ovl_config *config)
}
}
- /* Workdir is useless in non-upper mount */
- if (!config->upperdir && config->workdir) {
- pr_info("option \"workdir=%s\" is useless in a non-upper mount, ignore\n",
- config->workdir);
- kfree(config->workdir);
- config->workdir = NULL;
+ /* Workdir/index are useless in non-upper mount */
+ if (!config->upperdir) {
+ if (config->workdir) {
+ pr_info("option \"workdir=%s\" is useless in a non-upper mount, ignore\n",
+ config->workdir);
+ kfree(config->workdir);
+ config->workdir = NULL;
+ }
+ if (config->index && index_opt) {
+ pr_info("option \"index=on\" is useless in a non-upper mount, ignore\n");
+ index_opt = false;
+ }
+ config->index = false;
}
err = ovl_parse_redirect_mode(config, config->redirect_mode);
@@ -622,11 +629,13 @@ static int ovl_parse_opt(char *opt, struct ovl_config *config)
/* Resolve nfs_export -> index dependency */
if (config->nfs_export && !config->index) {
- if (nfs_export_opt && index_opt) {
+ if (!config->upperdir && config->redirect_follow) {
+ pr_info("NFS export requires \"redirect_dir=nofollow\" on non-upper mount, falling back to nfs_export=off.\n");
+ config->nfs_export = false;
+ } else if (nfs_export_opt && index_opt) {
pr_err("conflicting options: nfs_export=on,index=off\n");
return -EINVAL;
- }
- if (index_opt) {
+ } else if (index_opt) {
/*
* There was an explicit index=off that resulted
* in this conflict.
@@ -1352,8 +1361,15 @@ static int ovl_get_indexdir(struct super_block *sb, struct ovl_fs *ofs,
goto out;
}
+ /* index dir will act also as workdir */
+ iput(ofs->workdir_trap);
+ ofs->workdir_trap = NULL;
+ dput(ofs->workdir);
+ ofs->workdir = NULL;
ofs->indexdir = ovl_workdir_create(ofs, OVL_INDEXDIR_NAME, true);
if (ofs->indexdir) {
+ ofs->workdir = dget(ofs->indexdir);
+
err = ovl_setup_trap(sb, ofs->indexdir, &ofs->indexdir_trap,
"indexdir");
if (err)
@@ -1396,6 +1412,18 @@ static bool ovl_lower_uuid_ok(struct ovl_fs *ofs, const uuid_t *uuid)
if (!ofs->config.nfs_export && !ovl_upper_mnt(ofs))
return true;
+ /*
+ * We allow using single lower with null uuid for index and nfs_export
+ * for example to support those features with single lower squashfs.
+ * To avoid regressions in setups of overlay with re-formatted lower
+ * squashfs, do not allow decoding origin with lower null uuid unless
+ * user opted-in to one of the new features that require following the
+ * lower inode of non-dir upper.
+ */
+ if (!ofs->config.index && !ofs->config.metacopy && !ofs->config.xino &&
+ uuid_is_null(uuid))
+ return false;
+
for (i = 0; i < ofs->numfs; i++) {
/*
* We use uuid to associate an overlay lower file handle with a
@@ -1493,14 +1521,23 @@ static int ovl_get_layers(struct super_block *sb, struct ovl_fs *ofs,
if (err < 0)
goto out;
+ /*
+ * Check if lower root conflicts with this overlay layers before
+ * checking if it is in-use as upperdir/workdir of "another"
+ * mount, because we do not bother to check in ovl_is_inuse() if
+ * the upperdir/workdir is in fact in-use by our
+ * upperdir/workdir.
+ */
err = ovl_setup_trap(sb, stack[i].dentry, &trap, "lowerdir");
if (err)
goto out;
if (ovl_is_inuse(stack[i].dentry)) {
err = ovl_report_in_use(ofs, "lowerdir");
- if (err)
+ if (err) {
+ iput(trap);
goto out;
+ }
}
mnt = clone_private_mount(&stack[i]);
@@ -1575,10 +1612,6 @@ static struct ovl_entry *ovl_get_lowerstack(struct super_block *sb,
if (!ofs->config.upperdir && numlower == 1) {
pr_err("at least 2 lowerdir are needed while upperdir nonexistent\n");
return ERR_PTR(-EINVAL);
- } else if (!ofs->config.upperdir && ofs->config.nfs_export &&
- ofs->config.redirect_follow) {
- pr_warn("NFS export requires \"redirect_dir=nofollow\" on non-upper mount, falling back to nfs_export=off.\n");
- ofs->config.nfs_export = false;
}
stack = kcalloc(numlower, sizeof(struct path), GFP_KERNEL);
@@ -1842,21 +1875,13 @@ static int ovl_fill_super(struct super_block *sb, void *data, int silent)
if (!ovl_upper_mnt(ofs))
sb->s_flags |= SB_RDONLY;
- if (!(ovl_force_readonly(ofs)) && ofs->config.index) {
- /* index dir will act also as workdir */
- dput(ofs->workdir);
- ofs->workdir = NULL;
- iput(ofs->workdir_trap);
- ofs->workdir_trap = NULL;
-
+ if (!ovl_force_readonly(ofs) && ofs->config.index) {
err = ovl_get_indexdir(sb, ofs, oe, &upperpath);
if (err)
goto out_free_oe;
/* Force r/o mount with no index dir */
- if (ofs->indexdir)
- ofs->workdir = dget(ofs->indexdir);
- else
+ if (!ofs->indexdir)
sb->s_flags |= SB_RDONLY;
}