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-rw-r--r--fs/overlayfs/copy_up.c20
-rw-r--r--fs/overlayfs/dir.c138
-rw-r--r--fs/overlayfs/overlayfs.h4
-rw-r--r--fs/overlayfs/ovl_entry.h1
-rw-r--r--fs/overlayfs/super.c12
-rw-r--r--fs/overlayfs/util.c29
6 files changed, 176 insertions, 28 deletions
diff --git a/fs/overlayfs/copy_up.c b/fs/overlayfs/copy_up.c
index f18c1a616e9e..e191c631b17f 100644
--- a/fs/overlayfs/copy_up.c
+++ b/fs/overlayfs/copy_up.c
@@ -324,17 +324,11 @@ out_cleanup:
/*
* Copy up a single dentry
*
- * Directory renames only allowed on "pure upper" (already created on
- * upper filesystem, never copied up). Directories which are on lower or
- * are merged may not be renamed. For these -EXDEV is returned and
- * userspace has to deal with it. This means, when copying up a
- * directory we can rely on it and ancestors being stable.
- *
- * Non-directory renames start with copy up of source if necessary. The
- * actual rename will only proceed once the copy up was successful. Copy
- * up uses upper parent i_mutex for exclusion. Since rename can change
- * d_parent it is possible that the copy up will lock the old parent. At
- * that point the file will have already been copied up anyway.
+ * All renames start with copy up of source if necessary. The actual
+ * rename will only proceed once the copy up was successful. Copy up uses
+ * upper parent i_mutex for exclusion. Since rename can change d_parent it
+ * is possible that the copy up will lock the old parent. At that point
+ * the file will have already been copied up anyway.
*/
int ovl_copy_up_one(struct dentry *parent, struct dentry *dentry,
struct path *lowerpath, struct kstat *stat)
@@ -346,7 +340,6 @@ int ovl_copy_up_one(struct dentry *parent, struct dentry *dentry,
struct path parentpath;
struct dentry *lowerdentry = lowerpath->dentry;
struct dentry *upperdir;
- struct dentry *upperdentry;
const char *link = NULL;
if (WARN_ON(!workdir))
@@ -372,8 +365,7 @@ int ovl_copy_up_one(struct dentry *parent, struct dentry *dentry,
pr_err("overlayfs: failed to lock workdir+upperdir\n");
goto out_unlock;
}
- upperdentry = ovl_dentry_upper(dentry);
- if (upperdentry) {
+ if (ovl_dentry_upper(dentry)) {
/* Raced with another copy-up? Nothing to do, then... */
err = 0;
goto out_unlock;
diff --git a/fs/overlayfs/dir.c b/fs/overlayfs/dir.c
index f24b6b967901..c1de84c1c5ec 100644
--- a/fs/overlayfs/dir.c
+++ b/fs/overlayfs/dir.c
@@ -15,6 +15,7 @@
#include <linux/posix_acl.h>
#include <linux/posix_acl_xattr.h>
#include <linux/atomic.h>
+#include <linux/ratelimit.h>
#include "overlayfs.h"
void ovl_cleanup(struct inode *wdir, struct dentry *wdentry)
@@ -757,6 +758,104 @@ static bool ovl_type_merge_or_lower(struct dentry *dentry)
return OVL_TYPE_MERGE(type) || !OVL_TYPE_UPPER(type);
}
+static bool ovl_can_move(struct dentry *dentry)
+{
+ return ovl_redirect_dir(dentry->d_sb) ||
+ !d_is_dir(dentry) || !ovl_type_merge_or_lower(dentry);
+}
+
+#define OVL_REDIRECT_MAX 256
+
+static char *ovl_get_redirect(struct dentry *dentry, bool samedir)
+{
+ char *buf, *ret;
+ struct dentry *d, *tmp;
+ int buflen = OVL_REDIRECT_MAX + 1;
+
+ if (samedir) {
+ ret = kstrndup(dentry->d_name.name, dentry->d_name.len,
+ GFP_KERNEL);
+ goto out;
+ }
+
+ buf = ret = kmalloc(buflen, GFP_TEMPORARY);
+ if (!buf)
+ goto out;
+
+ buflen--;
+ buf[buflen] = '\0';
+ for (d = dget(dentry); !IS_ROOT(d);) {
+ const char *name;
+ int thislen;
+
+ spin_lock(&d->d_lock);
+ name = ovl_dentry_get_redirect(d);
+ if (name) {
+ thislen = strlen(name);
+ } else {
+ name = d->d_name.name;
+ thislen = d->d_name.len;
+ }
+
+ /* If path is too long, fall back to userspace move */
+ if (thislen + (name[0] != '/') > buflen) {
+ ret = ERR_PTR(-EXDEV);
+ spin_unlock(&d->d_lock);
+ goto out_put;
+ }
+
+ buflen -= thislen;
+ memcpy(&buf[buflen], name, thislen);
+ tmp = dget_dlock(d->d_parent);
+ spin_unlock(&d->d_lock);
+
+ dput(d);
+ d = tmp;
+
+ /* Absolute redirect: finished */
+ if (buf[buflen] == '/')
+ break;
+ buflen--;
+ buf[buflen] = '/';
+ }
+ ret = kstrdup(&buf[buflen], GFP_KERNEL);
+out_put:
+ dput(d);
+ kfree(buf);
+out:
+ return ret ? ret : ERR_PTR(-ENOMEM);
+}
+
+static int ovl_set_redirect(struct dentry *dentry, bool samedir)
+{
+ int err;
+ const char *redirect = ovl_dentry_get_redirect(dentry);
+
+ if (redirect && (samedir || redirect[0] == '/'))
+ return 0;
+
+ redirect = ovl_get_redirect(dentry, samedir);
+ if (IS_ERR(redirect))
+ return PTR_ERR(redirect);
+
+ err = ovl_do_setxattr(ovl_dentry_upper(dentry), OVL_XATTR_REDIRECT,
+ redirect, strlen(redirect), 0);
+ if (!err) {
+ spin_lock(&dentry->d_lock);
+ ovl_dentry_set_redirect(dentry, redirect);
+ spin_unlock(&dentry->d_lock);
+ } else {
+ kfree(redirect);
+ if (err == -EOPNOTSUPP)
+ ovl_clear_redirect_dir(dentry->d_sb);
+ else
+ pr_warn_ratelimited("overlay: failed to set redirect (%i)\n", err);
+ /* Fall back to userspace copy-up */
+ err = -EXDEV;
+ }
+ return err;
+}
+
static int ovl_rename(struct inode *olddir, struct dentry *old,
struct inode *newdir, struct dentry *new,
unsigned int flags)
@@ -773,6 +872,7 @@ static int ovl_rename(struct inode *olddir, struct dentry *old,
bool overwrite = !(flags & RENAME_EXCHANGE);
bool is_dir = d_is_dir(old);
bool new_is_dir = d_is_dir(new);
+ bool samedir = olddir == newdir;
struct dentry *opaquedir = NULL;
const struct cred *old_cred = NULL;
@@ -784,9 +884,9 @@ static int ovl_rename(struct inode *olddir, struct dentry *old,
/* Don't copy up directory trees */
err = -EXDEV;
- if (is_dir && ovl_type_merge_or_lower(old))
+ if (!ovl_can_move(old))
goto out;
- if (!overwrite && new_is_dir && ovl_type_merge_or_lower(new))
+ if (!overwrite && !ovl_can_move(new))
goto out;
err = ovl_want_write(old);
@@ -837,7 +937,6 @@ static int ovl_rename(struct inode *olddir, struct dentry *old,
trap = lock_rename(new_upperdir, old_upperdir);
-
olddentry = lookup_one_len(old->d_name.name, old_upperdir,
old->d_name.len);
err = PTR_ERR(olddentry);
@@ -880,18 +979,29 @@ static int ovl_rename(struct inode *olddir, struct dentry *old,
if (WARN_ON(olddentry->d_inode == newdentry->d_inode))
goto out_dput;
- if (is_dir && !old_opaque && ovl_lower_positive(new)) {
- err = ovl_set_opaque(olddentry);
- if (err)
- goto out_dput;
- ovl_dentry_set_opaque(old, true);
+ if (is_dir) {
+ if (ovl_type_merge_or_lower(old)) {
+ err = ovl_set_redirect(old, samedir);
+ if (err)
+ goto out_dput;
+ } else if (!old_opaque && ovl_lower_positive(new)) {
+ err = ovl_set_opaque(olddentry);
+ if (err)
+ goto out_dput;
+ ovl_dentry_set_opaque(old, true);
+ }
}
- if (!overwrite &&
- new_is_dir && !new_opaque && ovl_lower_positive(old)) {
- err = ovl_set_opaque(newdentry);
- if (err)
- goto out_dput;
- ovl_dentry_set_opaque(new, true);
+ if (!overwrite && new_is_dir) {
+ if (ovl_type_merge_or_lower(new)) {
+ err = ovl_set_redirect(new, samedir);
+ if (err)
+ goto out_dput;
+ } else if (!new_opaque && ovl_lower_positive(old)) {
+ err = ovl_set_opaque(newdentry);
+ if (err)
+ goto out_dput;
+ ovl_dentry_set_opaque(new, true);
+ }
}
err = ovl_do_rename(old_upperdir->d_inode, olddentry,
diff --git a/fs/overlayfs/overlayfs.h b/fs/overlayfs/overlayfs.h
index e76d9d529e64..bdda37fa3f67 100644
--- a/fs/overlayfs/overlayfs.h
+++ b/fs/overlayfs/overlayfs.h
@@ -157,6 +157,10 @@ void ovl_set_dir_cache(struct dentry *dentry, struct ovl_dir_cache *cache);
bool ovl_dentry_is_opaque(struct dentry *dentry);
bool ovl_dentry_is_whiteout(struct dentry *dentry);
void ovl_dentry_set_opaque(struct dentry *dentry, bool opaque);
+bool ovl_redirect_dir(struct super_block *sb);
+void ovl_clear_redirect_dir(struct super_block *sb);
+const char *ovl_dentry_get_redirect(struct dentry *dentry);
+void ovl_dentry_set_redirect(struct dentry *dentry, const char *redirect);
void ovl_dentry_update(struct dentry *dentry, struct dentry *upperdentry);
void ovl_inode_init(struct inode *inode, struct inode *realinode,
bool is_upper);
diff --git a/fs/overlayfs/ovl_entry.h b/fs/overlayfs/ovl_entry.h
index eb29882b6a54..d14bca1850d9 100644
--- a/fs/overlayfs/ovl_entry.h
+++ b/fs/overlayfs/ovl_entry.h
@@ -13,6 +13,7 @@ struct ovl_config {
char *upperdir;
char *workdir;
bool default_permissions;
+ bool redirect_dir;
};
/* private information held for overlayfs's superblock */
diff --git a/fs/overlayfs/super.c b/fs/overlayfs/super.c
index 4e44e865b716..520f9ab0e9ef 100644
--- a/fs/overlayfs/super.c
+++ b/fs/overlayfs/super.c
@@ -226,6 +226,8 @@ enum {
OPT_UPPERDIR,
OPT_WORKDIR,
OPT_DEFAULT_PERMISSIONS,
+ OPT_REDIRECT_DIR_ON,
+ OPT_REDIRECT_DIR_OFF,
OPT_ERR,
};
@@ -234,6 +236,8 @@ static const match_table_t ovl_tokens = {
{OPT_UPPERDIR, "upperdir=%s"},
{OPT_WORKDIR, "workdir=%s"},
{OPT_DEFAULT_PERMISSIONS, "default_permissions"},
+ {OPT_REDIRECT_DIR_ON, "redirect_dir=on"},
+ {OPT_REDIRECT_DIR_OFF, "redirect_dir=off"},
{OPT_ERR, NULL}
};
@@ -298,6 +302,14 @@ static int ovl_parse_opt(char *opt, struct ovl_config *config)
config->default_permissions = true;
break;
+ case OPT_REDIRECT_DIR_ON:
+ config->redirect_dir = true;
+ break;
+
+ case OPT_REDIRECT_DIR_OFF:
+ config->redirect_dir = false;
+ break;
+
default:
pr_err("overlayfs: unrecognized mount option \"%s\" or missing value\n", p);
return -EINVAL;
diff --git a/fs/overlayfs/util.c b/fs/overlayfs/util.c
index 0d45a84468d2..260b215852a3 100644
--- a/fs/overlayfs/util.c
+++ b/fs/overlayfs/util.c
@@ -176,6 +176,35 @@ void ovl_dentry_set_opaque(struct dentry *dentry, bool opaque)
oe->opaque = opaque;
}
+bool ovl_redirect_dir(struct super_block *sb)
+{
+ struct ovl_fs *ofs = sb->s_fs_info;
+
+ return ofs->config.redirect_dir;
+}
+
+void ovl_clear_redirect_dir(struct super_block *sb)
+{
+ struct ovl_fs *ofs = sb->s_fs_info;
+
+ ofs->config.redirect_dir = false;
+}
+
+const char *ovl_dentry_get_redirect(struct dentry *dentry)
+{
+ struct ovl_entry *oe = dentry->d_fsdata;
+
+ return oe->redirect;
+}
+
+void ovl_dentry_set_redirect(struct dentry *dentry, const char *redirect)
+{
+ struct ovl_entry *oe = dentry->d_fsdata;
+
+ kfree(oe->redirect);
+ oe->redirect = redirect;
+}
+
void ovl_dentry_update(struct dentry *dentry, struct dentry *upperdentry)
{
struct ovl_entry *oe = dentry->d_fsdata;
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-03 16:59:28 +0000