ovl: check whiteout on lowest layer as well
Not checking whiteouts on lowest layer was an optimization (there's nothing to white out there), but it could result in inconsitent behavior when a layer previously used as upper/middle is later used as lowest. Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
This commit is contained in:
Miklos Szeredi
Родитель
3d3c6b8939
Коммит
3e01cee3b9
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@ -80,23 +80,50 @@ static struct ovl_cache_entry *ovl_cache_entry_find(struct rb_root *root,
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return NULL;
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}
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static struct ovl_cache_entry *ovl_cache_entry_new(const char *name, int len,
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static struct ovl_cache_entry *ovl_cache_entry_new(struct dentry *dir,
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const char *name, int len,
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u64 ino, unsigned int d_type)
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{
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struct ovl_cache_entry *p;
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size_t size = offsetof(struct ovl_cache_entry, name[len + 1]);
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p = kmalloc(size, GFP_KERNEL);
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if (p) {
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memcpy(p->name, name, len);
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p->name[len] = '\0';
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p->len = len;
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p->type = d_type;
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p->ino = ino;
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p->is_whiteout = false;
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p->is_cursor = false;
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}
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if (!p)
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return NULL;
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memcpy(p->name, name, len);
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p->name[len] = '\0';
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p->len = len;
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p->type = d_type;
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p->ino = ino;
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p->is_whiteout = false;
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p->is_cursor = false;
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if (d_type == DT_CHR) {
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struct dentry *dentry;
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const struct cred *old_cred;
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struct cred *override_cred;
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override_cred = prepare_creds();
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if (!override_cred) {
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kfree(p);
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return NULL;
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}
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/*
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* CAP_DAC_OVERRIDE for lookup
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*/
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cap_raise(override_cred->cap_effective, CAP_DAC_OVERRIDE);
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old_cred = override_creds(override_cred);
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dentry = lookup_one_len(name, dir, len);
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if (!IS_ERR(dentry)) {
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p->is_whiteout = ovl_is_whiteout(dentry);
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dput(dentry);
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}
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revert_creds(old_cred);
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put_cred(override_cred);
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}
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return p;
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}
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@ -123,36 +150,10 @@ static int ovl_cache_entry_add_rb(struct ovl_readdir_data *rdd,
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return 0;
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}
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p = ovl_cache_entry_new(name, len, ino, d_type);
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p = ovl_cache_entry_new(rdd->dir, name, len, ino, d_type);
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if (p == NULL)
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return -ENOMEM;
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if (d_type == DT_CHR) {
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struct dentry *dentry;
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const struct cred *old_cred;
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struct cred *override_cred;
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override_cred = prepare_creds();
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if (!override_cred) {
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kfree(p);
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return -ENOMEM;
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}
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/*
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* CAP_DAC_OVERRIDE for lookup
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*/
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cap_raise(override_cred->cap_effective, CAP_DAC_OVERRIDE);
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old_cred = override_creds(override_cred);
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dentry = lookup_one_len(name, rdd->dir, len);
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if (!IS_ERR(dentry)) {
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p->is_whiteout = ovl_is_whiteout(dentry);
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dput(dentry);
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}
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revert_creds(old_cred);
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put_cred(override_cred);
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}
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list_add_tail(&p->l_node, rdd->list);
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rb_link_node(&p->node, parent, newp);
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rb_insert_color(&p->node, &rdd->root);
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@ -170,7 +171,7 @@ static int ovl_fill_lower(struct ovl_readdir_data *rdd,
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if (p) {
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list_move_tail(&p->l_node, &rdd->middle);
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} else {
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p = ovl_cache_entry_new(name, namelen, ino, d_type);
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p = ovl_cache_entry_new(rdd->dir, name, namelen, ino, d_type);
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if (p == NULL)
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rdd->err = -ENOMEM;
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else
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@ -229,6 +230,7 @@ static inline int ovl_dir_read(struct path *realpath,
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if (IS_ERR(realfile))
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return PTR_ERR(realfile);
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rdd->dir = realpath->dentry;
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rdd->ctx.pos = 0;
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do {
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rdd->count = 0;
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@ -274,7 +276,6 @@ static int ovl_dir_read_merged(struct dentry *dentry, struct list_head *list)
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next = ovl_path_next(idx, dentry, &realpath);
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if (next != -1) {
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rdd.dir = realpath.dentry;
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err = ovl_dir_read(&realpath, &rdd);
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if (err)
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break;
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@ -350,16 +350,12 @@ struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry,
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if (IS_ERR(this))
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goto out;
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/*
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* If this is not the lowermost layer, check whiteout and opaque
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* directory.
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*/
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if (poe->numlower && this) {
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if (this) {
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if (ovl_is_whiteout(this)) {
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dput(this);
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this = NULL;
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upperopaque = true;
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} else if (ovl_is_opaquedir(this)) {
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} else if (poe->numlower && ovl_is_opaquedir(this)) {
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upperopaque = true;
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}
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}
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@ -384,19 +380,16 @@ struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry,
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goto out_put;
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if (!this)
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continue;
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/*
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* If this is not the lowermost layer, check whiteout and opaque
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* directory.
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*/
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if (i < poe->numlower - 1) {
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if (ovl_is_whiteout(this)) {
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dput(this);
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break;
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} else if (ovl_is_opaquedir(this)) {
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opaque = true;
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}
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if (ovl_is_whiteout(this)) {
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dput(this);
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break;
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}
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/*
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* Only makes sense to check opaque dir if this is not the
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* lowermost layer.
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*/
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if (i < poe->numlower - 1 && ovl_is_opaquedir(this))
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opaque = true;
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/*
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* If this is a non-directory then stop here.
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*
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