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-rw-r--r--fs/overlayfs/copy_up.c3
-rw-r--r--fs/overlayfs/dir.c33
-rw-r--r--fs/overlayfs/super.c41
3 files changed, 62 insertions, 15 deletions
diff --git a/fs/overlayfs/copy_up.c b/fs/overlayfs/copy_up.c
index 24f640441bd9..84d693d37428 100644
--- a/fs/overlayfs/copy_up.c
+++ b/fs/overlayfs/copy_up.c
@@ -299,6 +299,9 @@ int ovl_copy_up_one(struct dentry *parent, struct dentry *dentry,
struct cred *override_cred;
char *link = NULL;
+ if (WARN_ON(!workdir))
+ return -EROFS;
+
ovl_path_upper(parent, &parentpath);
upperdir = parentpath.dentry;
diff --git a/fs/overlayfs/dir.c b/fs/overlayfs/dir.c
index d139405d2bfa..692ceda3bc21 100644
--- a/fs/overlayfs/dir.c
+++ b/fs/overlayfs/dir.c
@@ -222,6 +222,9 @@ static struct dentry *ovl_clear_empty(struct dentry *dentry,
struct kstat stat;
int err;
+ if (WARN_ON(!workdir))
+ return ERR_PTR(-EROFS);
+
err = ovl_lock_rename_workdir(workdir, upperdir);
if (err)
goto out;
@@ -322,6 +325,9 @@ static int ovl_create_over_whiteout(struct dentry *dentry, struct inode *inode,
struct dentry *newdentry;
int err;
+ if (WARN_ON(!workdir))
+ return -EROFS;
+
err = ovl_lock_rename_workdir(workdir, upperdir);
if (err)
goto out;
@@ -506,11 +512,28 @@ static int ovl_remove_and_whiteout(struct dentry *dentry, bool is_dir)
struct dentry *opaquedir = NULL;
int err;
- if (is_dir && OVL_TYPE_MERGE_OR_LOWER(ovl_path_type(dentry))) {
- opaquedir = ovl_check_empty_and_clear(dentry);
- err = PTR_ERR(opaquedir);
- if (IS_ERR(opaquedir))
- goto out;
+ if (WARN_ON(!workdir))
+ return -EROFS;
+
+ if (is_dir) {
+ if (OVL_TYPE_MERGE_OR_LOWER(ovl_path_type(dentry))) {
+ opaquedir = ovl_check_empty_and_clear(dentry);
+ err = PTR_ERR(opaquedir);
+ if (IS_ERR(opaquedir))
+ goto out;
+ } else {
+ LIST_HEAD(list);
+
+ /*
+ * When removing an empty opaque directory, then it
+ * makes no sense to replace it with an exact replica of
+ * itself. But emptiness still needs to be checked.
+ */
+ err = ovl_check_empty_dir(dentry, &list);
+ ovl_cache_free(&list);
+ if (err)
+ goto out;
+ }
}
err = ovl_lock_rename_workdir(workdir, upperdir);
diff --git a/fs/overlayfs/super.c b/fs/overlayfs/super.c
index b90952f528b1..bf8537c7f455 100644
--- a/fs/overlayfs/super.c
+++ b/fs/overlayfs/super.c
@@ -529,8 +529,7 @@ static int ovl_remount(struct super_block *sb, int *flags, char *data)
{
struct ovl_fs *ufs = sb->s_fs_info;
- if (!(*flags & MS_RDONLY) &&
- (!ufs->upper_mnt || (ufs->upper_mnt->mnt_sb->s_flags & MS_RDONLY)))
+ if (!(*flags & MS_RDONLY) && (!ufs->upper_mnt || !ufs->workdir))
return -EROFS;
return 0;
@@ -615,9 +614,19 @@ static int ovl_parse_opt(char *opt, struct ovl_config *config)
break;
default:
+ pr_err("overlayfs: unrecognized mount option \"%s\" or missing value\n", p);
return -EINVAL;
}
}
+
+ /* Workdir is useless in non-upper mount */
+ if (!config->upperdir && config->workdir) {
+ pr_info("overlayfs: option \"workdir=%s\" is useless in a non-upper mount, ignore\n",
+ config->workdir);
+ kfree(config->workdir);
+ config->workdir = NULL;
+ }
+
return 0;
}
@@ -837,7 +846,6 @@ static int ovl_fill_super(struct super_block *sb, void *data, int silent)
sb->s_stack_depth = 0;
if (ufs->config.upperdir) {
- /* FIXME: workdir is not needed for a R/O mount */
if (!ufs->config.workdir) {
pr_err("overlayfs: missing 'workdir'\n");
goto out_free_config;
@@ -847,6 +855,13 @@ static int ovl_fill_super(struct super_block *sb, void *data, int silent)
if (err)
goto out_free_config;
+ /* Upper fs should not be r/o */
+ if (upperpath.mnt->mnt_sb->s_flags & MS_RDONLY) {
+ pr_err("overlayfs: upper fs is r/o, try multi-lower layers mount\n");
+ err = -EINVAL;
+ goto out_put_upperpath;
+ }
+
err = ovl_mount_dir(ufs->config.workdir, &workpath);
if (err)
goto out_put_upperpath;
@@ -869,8 +884,14 @@ static int ovl_fill_super(struct super_block *sb, void *data, int silent)
err = -EINVAL;
stacklen = ovl_split_lowerdirs(lowertmp);
- if (stacklen > OVL_MAX_STACK)
+ if (stacklen > OVL_MAX_STACK) {
+ pr_err("overlayfs: too many lower directries, limit is %d\n",
+ OVL_MAX_STACK);
goto out_free_lowertmp;
+ } else if (!ufs->config.upperdir && stacklen == 1) {
+ pr_err("overlayfs: at least 2 lowerdir are needed while upperdir nonexistent\n");
+ goto out_free_lowertmp;
+ }
stack = kcalloc(stacklen, sizeof(struct path), GFP_KERNEL);
if (!stack)
@@ -904,9 +925,10 @@ static int ovl_fill_super(struct super_block *sb, void *data, int silent)
ufs->workdir = ovl_workdir_create(ufs->upper_mnt, workpath.dentry);
err = PTR_ERR(ufs->workdir);
if (IS_ERR(ufs->workdir)) {
- pr_err("overlayfs: failed to create directory %s/%s\n",
- ufs->config.workdir, OVL_WORKDIR_NAME);
- goto out_put_upper_mnt;
+ pr_warn("overlayfs: failed to create directory %s/%s (errno: %i); mounting read-only\n",
+ ufs->config.workdir, OVL_WORKDIR_NAME, -err);
+ sb->s_flags |= MS_RDONLY;
+ ufs->workdir = NULL;
}
}
@@ -932,8 +954,8 @@ static int ovl_fill_super(struct super_block *sb, void *data, int silent)
ufs->numlower++;
}
- /* If the upper fs is r/o or nonexistent, we mark overlayfs r/o too */
- if (!ufs->upper_mnt || (ufs->upper_mnt->mnt_sb->s_flags & MS_RDONLY))
+ /* If the upper fs is nonexistent, we mark overlayfs r/o too */
+ if (!ufs->upper_mnt)
sb->s_flags |= MS_RDONLY;
sb->s_d_op = &ovl_dentry_operations;
@@ -976,7 +998,6 @@ out_put_lower_mnt:
kfree(ufs->lower_mnt);
out_put_workdir:
dput(ufs->workdir);
-out_put_upper_mnt:
mntput(ufs->upper_mnt);
out_put_lowerpath:
for (i = 0; i < numlower; i++)
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