#include <linux/xattr.h>
#include <linux/security.h>
#include <linux/cred.h>
+#include <linux/module.h>
#include <linux/posix_acl.h>
#include <linux/posix_acl_xattr.h>
#include <linux/atomic.h>
+#include <linux/ratelimit.h>
#include "overlayfs.h"
+static unsigned short ovl_redirect_max = 256;
+module_param_named(redirect_max, ovl_redirect_max, ushort, 0644);
+MODULE_PARM_DESC(ovl_redirect_max,
+ "Maximum length of absolute redirect xattr value");
+
void ovl_cleanup(struct inode *wdir, struct dentry *wdentry)
{
int err;
}
int ovl_create_real(struct inode *dir, struct dentry *newdentry,
- struct kstat *stat, const char *link,
- struct dentry *hardlink, bool debug)
+ struct cattr *attr, struct dentry *hardlink, bool debug)
{
int err;
if (hardlink) {
err = ovl_do_link(hardlink, dir, newdentry, debug);
} else {
- switch (stat->mode & S_IFMT) {
+ switch (attr->mode & S_IFMT) {
case S_IFREG:
- err = ovl_do_create(dir, newdentry, stat->mode, debug);
+ err = ovl_do_create(dir, newdentry, attr->mode, debug);
break;
case S_IFDIR:
- err = ovl_do_mkdir(dir, newdentry, stat->mode, debug);
+ err = ovl_do_mkdir(dir, newdentry, attr->mode, debug);
break;
case S_IFCHR:
case S_IFIFO:
case S_IFSOCK:
err = ovl_do_mknod(dir, newdentry,
- stat->mode, stat->rdev, debug);
+ attr->mode, attr->rdev, debug);
break;
case S_IFLNK:
- err = ovl_do_symlink(dir, newdentry, link, debug);
+ err = ovl_do_symlink(dir, newdentry, attr->link, debug);
break;
default:
return err;
}
-static int ovl_set_opaque(struct dentry *upperdentry)
-{
- return ovl_do_setxattr(upperdentry, OVL_XATTR_OPAQUE, "y", 1, 0);
-}
-
-static void ovl_remove_opaque(struct dentry *upperdentry)
+static int ovl_set_opaque(struct dentry *dentry, struct dentry *upperdentry)
{
int err;
- err = ovl_do_removexattr(upperdentry, OVL_XATTR_OPAQUE);
- if (err) {
- pr_warn("overlayfs: failed to remove opaque from '%s' (%i)\n",
- upperdentry->d_name.name, err);
- }
+ err = ovl_do_setxattr(upperdentry, OVL_XATTR_OPAQUE, "y", 1, 0);
+ if (!err)
+ ovl_dentry_set_opaque(dentry);
+
+ return err;
}
static int ovl_dir_getattr(struct vfsmount *mnt, struct dentry *dentry,
d_instantiate(dentry, inode);
}
+static bool ovl_type_merge(struct dentry *dentry)
+{
+ return OVL_TYPE_MERGE(ovl_path_type(dentry));
+}
+
static int ovl_create_upper(struct dentry *dentry, struct inode *inode,
- struct kstat *stat, const char *link,
- struct dentry *hardlink)
+ struct cattr *attr, struct dentry *hardlink)
{
struct dentry *upperdir = ovl_dentry_upper(dentry->d_parent);
struct inode *udir = upperdir->d_inode;
int err;
if (!hardlink && !IS_POSIXACL(udir))
- stat->mode &= ~current_umask();
+ attr->mode &= ~current_umask();
inode_lock_nested(udir, I_MUTEX_PARENT);
newdentry = lookup_one_len(dentry->d_name.name, upperdir,
err = PTR_ERR(newdentry);
if (IS_ERR(newdentry))
goto out_unlock;
- err = ovl_create_real(udir, newdentry, stat, link, hardlink, false);
+ err = ovl_create_real(udir, newdentry, attr, hardlink, false);
if (err)
goto out_dput;
+ if (ovl_type_merge(dentry->d_parent)) {
+ /* Setting opaque here is just an optimization, allow to fail */
+ ovl_set_opaque(dentry, newdentry);
+ }
+
ovl_instantiate(dentry, inode, newdentry, !!hardlink);
newdentry = NULL;
out_dput:
if (IS_ERR(opaquedir))
goto out_unlock;
- err = ovl_create_real(wdir, opaquedir, &stat, NULL, NULL, true);
+ err = ovl_create_real(wdir, opaquedir,
+ &(struct cattr){.mode = stat.mode}, NULL, true);
if (err)
goto out_dput;
if (err)
goto out_cleanup;
- err = ovl_set_opaque(opaquedir);
+ err = ovl_set_opaque(dentry, opaquedir);
if (err)
goto out_cleanup;
}
static int ovl_create_over_whiteout(struct dentry *dentry, struct inode *inode,
- struct kstat *stat, const char *link,
+ struct cattr *cattr,
struct dentry *hardlink)
{
struct dentry *workdir = ovl_workdir(dentry);
if (!hardlink) {
err = posix_acl_create(dentry->d_parent->d_inode,
- &stat->mode, &default_acl, &acl);
+ &cattr->mode, &default_acl, &acl);
if (err)
return err;
}
if (IS_ERR(upper))
goto out_dput;
- err = ovl_create_real(wdir, newdentry, stat, link, hardlink, true);
+ err = ovl_create_real(wdir, newdentry, cattr, hardlink, true);
if (err)
goto out_dput2;
* mode could have been mutilated due to umask (e.g. sgid directory)
*/
if (!hardlink &&
- !S_ISLNK(stat->mode) && newdentry->d_inode->i_mode != stat->mode) {
+ !S_ISLNK(cattr->mode) &&
+ newdentry->d_inode->i_mode != cattr->mode) {
struct iattr attr = {
.ia_valid = ATTR_MODE,
- .ia_mode = stat->mode,
+ .ia_mode = cattr->mode,
};
inode_lock(newdentry->d_inode);
err = notify_change(newdentry, &attr, NULL);
goto out_cleanup;
}
- if (!hardlink && S_ISDIR(stat->mode)) {
- err = ovl_set_opaque(newdentry);
+ if (!hardlink && S_ISDIR(cattr->mode)) {
+ err = ovl_set_opaque(dentry, newdentry);
if (err)
goto out_cleanup;
}
static int ovl_create_or_link(struct dentry *dentry, struct inode *inode,
- struct kstat *stat, const char *link,
- struct dentry *hardlink)
+ struct cattr *attr, struct dentry *hardlink)
{
int err;
const struct cred *old_cred;
override_cred->fsgid = inode->i_gid;
if (!hardlink) {
err = security_dentry_create_files_as(dentry,
- stat->mode, &dentry->d_name, old_cred,
+ attr->mode, &dentry->d_name, old_cred,
override_cred);
if (err) {
put_cred(override_cred);
put_cred(override_creds(override_cred));
put_cred(override_cred);
- if (!ovl_dentry_is_opaque(dentry))
- err = ovl_create_upper(dentry, inode, stat, link,
+ if (!ovl_dentry_is_whiteout(dentry))
+ err = ovl_create_upper(dentry, inode, attr,
hardlink);
else
- err = ovl_create_over_whiteout(dentry, inode, stat,
- link, hardlink);
+ err = ovl_create_over_whiteout(dentry, inode, attr,
+ hardlink);
}
out_revert_creds:
revert_creds(old_cred);
{
int err;
struct inode *inode;
- struct kstat stat = {
+ struct cattr attr = {
.rdev = rdev,
+ .link = link,
};
err = ovl_want_write(dentry);
goto out;
err = -ENOMEM;
- inode = ovl_new_inode(dentry->d_sb, mode);
+ inode = ovl_new_inode(dentry->d_sb, mode, rdev);
if (!inode)
goto out_drop_write;
inode_init_owner(inode, dentry->d_parent->d_inode, mode);
- stat.mode = inode->i_mode;
+ attr.mode = inode->i_mode;
- err = ovl_create_or_link(dentry, inode, &stat, link, NULL);
+ err = ovl_create_or_link(dentry, inode, &attr, NULL);
if (err)
iput(inode);
inode = d_inode(old);
ihold(inode);
- err = ovl_create_or_link(new, inode, NULL, NULL, ovl_dentry_upper(old));
+ err = ovl_create_or_link(new, inode, NULL, ovl_dentry_upper(old));
if (err)
iput(inode);
struct dentry *upperdir = ovl_dentry_upper(dentry->d_parent);
struct inode *dir = upperdir->d_inode;
struct dentry *upper;
+ struct dentry *opaquedir = NULL;
int err;
+ /* Redirect dir can be !ovl_lower_positive && OVL_TYPE_MERGE */
+ if (is_dir && ovl_dentry_get_redirect(dentry)) {
+ opaquedir = ovl_check_empty_and_clear(dentry);
+ err = PTR_ERR(opaquedir);
+ if (IS_ERR(opaquedir))
+ goto out;
+ }
+
inode_lock_nested(dir, I_MUTEX_PARENT);
upper = lookup_one_len(dentry->d_name.name, upperdir,
dentry->d_name.len);
goto out_unlock;
err = -ESTALE;
- if (upper == ovl_dentry_upper(dentry)) {
- if (is_dir)
- err = vfs_rmdir(dir, upper);
- else
- err = vfs_unlink(dir, upper, NULL);
- ovl_dentry_version_inc(dentry->d_parent);
- }
- dput(upper);
+ if ((opaquedir && upper != opaquedir) ||
+ (!opaquedir && upper != ovl_dentry_upper(dentry)))
+ goto out_dput_upper;
+
+ if (is_dir)
+ err = vfs_rmdir(dir, upper);
+ else
+ err = vfs_unlink(dir, upper, NULL);
+ ovl_dentry_version_inc(dentry->d_parent);
/*
* Keeping this dentry hashed would mean having to release
*/
if (!err)
d_drop(dentry);
+out_dput_upper:
+ dput(upper);
out_unlock:
inode_unlock(dir);
-
+ dput(opaquedir);
+out:
return err;
}
-static inline int ovl_check_sticky(struct dentry *dentry)
-{
- struct inode *dir = ovl_dentry_real(dentry->d_parent)->d_inode;
- struct inode *inode = ovl_dentry_real(dentry)->d_inode;
-
- if (check_sticky(dir, inode))
- return -EPERM;
-
- return 0;
-}
-
static int ovl_do_remove(struct dentry *dentry, bool is_dir)
{
enum ovl_path_type type;
int err;
const struct cred *old_cred;
-
- err = ovl_check_sticky(dentry);
- if (err)
- goto out;
-
err = ovl_want_write(dentry);
if (err)
goto out;
type = ovl_path_type(dentry);
old_cred = ovl_override_creds(dentry->d_sb);
- if (OVL_TYPE_PURE_UPPER(type))
+ if (!ovl_lower_positive(dentry))
err = ovl_remove_upper(dentry, is_dir);
else
err = ovl_remove_and_whiteout(dentry, is_dir);
return ovl_do_remove(dentry, true);
}
-static int ovl_rename2(struct inode *olddir, struct dentry *old,
- struct inode *newdir, struct dentry *new,
- unsigned int flags)
+static bool ovl_type_merge_or_lower(struct dentry *dentry)
+{
+ enum ovl_path_type type = ovl_path_type(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);
+}
+
+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)
{
int err;
- enum ovl_path_type old_type;
- enum ovl_path_type new_type;
struct dentry *old_upperdir;
struct dentry *new_upperdir;
struct dentry *olddentry;
bool cleanup_whiteout = false;
bool overwrite = !(flags & RENAME_EXCHANGE);
bool is_dir = d_is_dir(old);
- bool new_is_dir = false;
+ bool new_is_dir = d_is_dir(new);
+ bool samedir = olddir == newdir;
struct dentry *opaquedir = NULL;
const struct cred *old_cred = NULL;
flags &= ~RENAME_NOREPLACE;
- err = ovl_check_sticky(old);
- if (err)
- goto out;
-
/* Don't copy up directory trees */
- old_type = ovl_path_type(old);
err = -EXDEV;
- if (OVL_TYPE_MERGE_OR_LOWER(old_type) && is_dir)
+ if (!ovl_can_move(old))
+ goto out;
+ if (!overwrite && !ovl_can_move(new))
goto out;
-
- if (new->d_inode) {
- err = ovl_check_sticky(new);
- if (err)
- goto out;
-
- if (d_is_dir(new))
- new_is_dir = true;
-
- new_type = ovl_path_type(new);
- err = -EXDEV;
- if (!overwrite && OVL_TYPE_MERGE_OR_LOWER(new_type) && new_is_dir)
- goto out;
-
- err = 0;
- if (!OVL_TYPE_UPPER(new_type) && !OVL_TYPE_UPPER(old_type)) {
- if (ovl_dentry_lower(old)->d_inode ==
- ovl_dentry_lower(new)->d_inode)
- goto out;
- }
- if (OVL_TYPE_UPPER(new_type) && OVL_TYPE_UPPER(old_type)) {
- if (ovl_dentry_upper(old)->d_inode ==
- ovl_dentry_upper(new)->d_inode)
- goto out;
- }
- } else {
- if (ovl_dentry_is_opaque(new))
- new_type = __OVL_PATH_UPPER;
- else
- new_type = __OVL_PATH_UPPER | __OVL_PATH_PURE;
- }
err = ovl_want_write(old);
if (err)
goto out_drop_write;
}
- old_opaque = !OVL_TYPE_PURE_UPPER(old_type);
- new_opaque = !OVL_TYPE_PURE_UPPER(new_type);
-
old_cred = ovl_override_creds(old->d_sb);
- if (overwrite && OVL_TYPE_MERGE_OR_LOWER(new_type) && new_is_dir) {
+ if (overwrite && new_is_dir && ovl_type_merge_or_lower(new)) {
opaquedir = ovl_check_empty_and_clear(new);
err = PTR_ERR(opaquedir);
if (IS_ERR(opaquedir)) {
}
if (overwrite) {
- if (old_opaque) {
- if (new->d_inode || !new_opaque) {
+ if (ovl_lower_positive(old)) {
+ if (!ovl_dentry_is_whiteout(new)) {
/* Whiteout source */
flags |= RENAME_WHITEOUT;
} else {
/* Switch whiteouts */
flags |= RENAME_EXCHANGE;
}
- } else if (is_dir && !new->d_inode && new_opaque) {
+ } else if (is_dir && ovl_dentry_is_whiteout(new)) {
flags |= RENAME_EXCHANGE;
cleanup_whiteout = true;
}
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);
if (IS_ERR(newdentry))
goto out_dput_old;
+ old_opaque = ovl_dentry_is_opaque(old);
+ new_opaque = ovl_dentry_is_opaque(new);
+
err = -ESTALE;
if (ovl_dentry_upper(new)) {
if (opaquedir) {
if (newdentry == trap)
goto out_dput;
- if (is_dir && !old_opaque && new_opaque) {
- err = ovl_set_opaque(olddentry);
+ if (WARN_ON(olddentry->d_inode == newdentry->d_inode))
+ goto out_dput;
+
+ err = 0;
+ if (is_dir) {
+ if (ovl_type_merge_or_lower(old))
+ err = ovl_set_redirect(old, samedir);
+ else if (!old_opaque && ovl_type_merge(new->d_parent))
+ err = ovl_set_opaque(old, olddentry);
if (err)
goto out_dput;
}
- if (!overwrite && new_is_dir && old_opaque && !new_opaque) {
- err = ovl_set_opaque(newdentry);
+ if (!overwrite && new_is_dir) {
+ if (ovl_type_merge_or_lower(new))
+ err = ovl_set_redirect(new, samedir);
+ else if (!new_opaque && ovl_type_merge(old->d_parent))
+ err = ovl_set_opaque(new, newdentry);
if (err)
goto out_dput;
}
- if (old_opaque || new_opaque) {
- err = ovl_do_rename(old_upperdir->d_inode, olddentry,
- new_upperdir->d_inode, newdentry,
- flags);
- } else {
- /* No debug for the plain case */
- BUG_ON(flags & ~RENAME_EXCHANGE);
- err = vfs_rename(old_upperdir->d_inode, olddentry,
- new_upperdir->d_inode, newdentry,
- NULL, flags);
- }
-
- if (err) {
- if (is_dir && !old_opaque && new_opaque)
- ovl_remove_opaque(olddentry);
- if (!overwrite && new_is_dir && old_opaque && !new_opaque)
- ovl_remove_opaque(newdentry);
+ err = ovl_do_rename(old_upperdir->d_inode, olddentry,
+ new_upperdir->d_inode, newdentry, flags);
+ if (err)
goto out_dput;
- }
-
- if (is_dir && old_opaque && !new_opaque)
- ovl_remove_opaque(olddentry);
- if (!overwrite && new_is_dir && !old_opaque && new_opaque)
- ovl_remove_opaque(newdentry);
-
- /*
- * Old dentry now lives in different location. Dentries in
- * lowerstack are stale. We cannot drop them here because
- * access to them is lockless. This could be only pure upper
- * or opaque directory - numlower is zero. Or upper non-dir
- * entry - its pureness is tracked by flag opaque.
- */
- if (old_opaque != new_opaque) {
- ovl_dentry_set_opaque(old, new_opaque);
- if (!overwrite)
- ovl_dentry_set_opaque(new, old_opaque);
- }
if (cleanup_whiteout)
ovl_cleanup(old_upperdir->d_inode, newdentry);
.symlink = ovl_symlink,
.unlink = ovl_unlink,
.rmdir = ovl_rmdir,
- .rename = ovl_rename2,
+ .rename = ovl_rename,
.link = ovl_link,
.setattr = ovl_setattr,
.create = ovl_create,
projects / linux-2.6-block.git / blobdiff