kernel: fix an overlayfs deadlock on rmdir
SVN-Revision: 26215v19.07.3_mercusys_ac12_duma
Felix Fietkau
13 years ago
parent
4e2339b032
commit
473ac1f87d
@ -0,0 +1,76 @@
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--- a/fs/overlayfs/overlayfs.c
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+++ b/fs/overlayfs/overlayfs.c
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@@ -1686,37 +1686,56 @@ static int ovl_check_empty_dir(struct de
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return err;
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}
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-static int ovl_unlink_whiteout(void *buf, const char *name, int namelen,
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- loff_t offset, u64 ino, unsigned int d_type)
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+static int ovl_fill_links(void *buf, const char *name, int namelen,
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+ loff_t offset, u64 ino, unsigned int d_type)
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{
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struct ovl_readdir_data *rdd = buf;
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+ struct ovl_cache_entry *p;
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- rdd->count++;
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- /* check d_type to filter out "." and ".." */
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- if (d_type == DT_LNK) {
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- struct dentry *dentry;
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+ if (d_type != DT_LNK)
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+ return 0;
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- dentry = lookup_one_len(name, rdd->dir, namelen);
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- if (IS_ERR(dentry)) {
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- rdd->err = PTR_ERR(dentry);
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- } else {
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- rdd->err = vfs_unlink(rdd->dir->d_inode, dentry);
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- dput(dentry);
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- }
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- }
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+ p = ovl_cache_entry_new(name, namelen, ino, d_type);
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+ if (!p)
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+ return -ENOMEM;
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- return rdd->err;
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+ list_add(&p->l_node, rdd->list);
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+ return 0;
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}
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static int ovl_remove_whiteouts(struct dentry *dentry)
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{
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struct path upperpath;
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- struct ovl_readdir_data rdd = { .list = NULL };
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+ LIST_HEAD(list);
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+ struct ovl_readdir_data rdd = { .list = &list };
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+ struct ovl_cache_entry *p, *t;
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+ int ret;
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ovl_path_upper(dentry, &upperpath);
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rdd.dir = upperpath.dentry;
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- return ovl_dir_read(&upperpath, &rdd, ovl_unlink_whiteout);
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+ ret = ovl_dir_read(&upperpath, &rdd, ovl_fill_links);
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+
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+ mutex_lock(&rdd.dir->d_inode->i_mutex);
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+ list_for_each_entry_safe(p, t, &list, l_node) {
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+ struct dentry *dentry;
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+
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+ if (!ret) {
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+ dentry = lookup_one_len(p->name, rdd.dir, p->len);
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+ if (IS_ERR(dentry)) {
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+ ret = PTR_ERR(dentry);
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+ } else {
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+ ret = vfs_unlink(rdd.dir->d_inode, dentry);
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+ dput(dentry);
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+ }
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+ }
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+
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+ list_del(&p->l_node);
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+ kfree(p);
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+ }
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+ mutex_unlock(&rdd.dir->d_inode->i_mutex);
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+
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+ return ret;
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}
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static int ovl_rmdir(struct inode *dir, struct dentry *dentry)
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@ -0,0 +1,76 @@
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--- a/fs/overlayfs/overlayfs.c
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+++ b/fs/overlayfs/overlayfs.c
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@@ -1700,37 +1700,56 @@ static int ovl_check_empty_dir(struct de
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return err;
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}
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-static int ovl_unlink_whiteout(void *buf, const char *name, int namelen,
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- loff_t offset, u64 ino, unsigned int d_type)
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+static int ovl_fill_links(void *buf, const char *name, int namelen,
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+ loff_t offset, u64 ino, unsigned int d_type)
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{
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struct ovl_readdir_data *rdd = buf;
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+ struct ovl_cache_entry *p;
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- rdd->count++;
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- /* check d_type to filter out "." and ".." */
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- if (d_type == DT_LNK) {
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- struct dentry *dentry;
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+ if (d_type != DT_LNK)
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+ return 0;
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- dentry = lookup_one_len(name, rdd->dir, namelen);
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- if (IS_ERR(dentry)) {
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- rdd->err = PTR_ERR(dentry);
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- } else {
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- rdd->err = vfs_unlink(rdd->dir->d_inode, dentry);
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- dput(dentry);
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- }
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- }
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+ p = ovl_cache_entry_new(name, namelen, ino, d_type);
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+ if (!p)
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+ return -ENOMEM;
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- return rdd->err;
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+ list_add(&p->l_node, rdd->list);
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+ return 0;
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}
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static int ovl_remove_whiteouts(struct dentry *dentry)
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{
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struct path upperpath;
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- struct ovl_readdir_data rdd = { .list = NULL };
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+ LIST_HEAD(list);
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+ struct ovl_readdir_data rdd = { .list = &list };
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+ struct ovl_cache_entry *p, *t;
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+ int ret;
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ovl_path_upper(dentry, &upperpath);
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rdd.dir = upperpath.dentry;
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- return ovl_dir_read(&upperpath, &rdd, ovl_unlink_whiteout);
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+ ret = ovl_dir_read(&upperpath, &rdd, ovl_fill_links);
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+
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+ mutex_lock(&rdd.dir->d_inode->i_mutex);
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+ list_for_each_entry_safe(p, t, &list, l_node) {
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+ struct dentry *dentry;
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+
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+ if (!ret) {
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+ dentry = lookup_one_len(p->name, rdd.dir, p->len);
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+ if (IS_ERR(dentry)) {
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+ ret = PTR_ERR(dentry);
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+ } else {
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+ ret = vfs_unlink(rdd.dir->d_inode, dentry);
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+ dput(dentry);
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+ }
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+ }
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+
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+ list_del(&p->l_node);
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+ kfree(p);
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+ }
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+ mutex_unlock(&rdd.dir->d_inode->i_mutex);
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+
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+ return ret;
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}
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static int ovl_rmdir(struct inode *dir, struct dentry *dentry)
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