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authorLinus Torvalds <torvalds@linux-foundation.org>2016-12-16 21:58:12 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2016-12-16 21:58:12 +0300
commitff0f962ca3c38239b299a70e7eea27abfbb979c3 (patch)
treeab37876cf2e8af4900f11f44ac4b96cb0f15e548 /fs/overlayfs
parent087a76d390cbb8c0d21ea0cb3672ab4a7bb76362 (diff)
parentc3c8699664800a68600f1988302173067eaeaffa (diff)
downloadlinux-ff0f962ca3c38239b299a70e7eea27abfbb979c3.tar.xz
Merge branch 'overlayfs-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs
Pull overlayfs updates from Miklos Szeredi: "This update contains: - try to clone on copy-up - allow renaming a directory - split source into managable chunks - misc cleanups and fixes It does not contain the read-only fd data inconsistency fix, which Al didn't like. I'll leave that to the next year..." * 'overlayfs-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs: (36 commits) ovl: fix reStructuredText syntax errors in documentation ovl: fix return value of ovl_fill_super ovl: clean up kstat usage ovl: fold ovl_copy_up_truncate() into ovl_copy_up() ovl: create directories inside merged parent opaque ovl: opaque cleanup ovl: show redirect_dir mount option ovl: allow setting max size of redirect ovl: allow redirect_dir to default to "on" ovl: check for emptiness of redirect dir ovl: redirect on rename-dir ovl: lookup redirects ovl: consolidate lookup for underlying layers ovl: fix nested overlayfs mount ovl: check namelen ovl: split super.c ovl: use d_is_dir() ovl: simplify lookup ovl: check lower existence of rename target ovl: rename: simplify handling of lower/merged directory ...
Diffstat (limited to 'fs/overlayfs')
-rw-r--r--fs/overlayfs/Kconfig14
-rw-r--r--fs/overlayfs/Makefile2
-rw-r--r--fs/overlayfs/copy_up.c61
-rw-r--r--fs/overlayfs/dir.c375
-rw-r--r--fs/overlayfs/inode.c78
-rw-r--r--fs/overlayfs/namei.c401
-rw-r--r--fs/overlayfs/overlayfs.h62
-rw-r--r--fs/overlayfs/ovl_entry.h53
-rw-r--r--fs/overlayfs/super.c557
-rw-r--r--fs/overlayfs/util.c265
10 files changed, 1084 insertions, 784 deletions
diff --git a/fs/overlayfs/Kconfig b/fs/overlayfs/Kconfig
index 34355818a2e0..0daac5112f7a 100644
--- a/fs/overlayfs/Kconfig
+++ b/fs/overlayfs/Kconfig
@@ -8,3 +8,17 @@ config OVERLAY_FS
merged with the 'upper' object.
For more information see Documentation/filesystems/overlayfs.txt
+
+config OVERLAY_FS_REDIRECT_DIR
+ bool "Overlayfs: turn on redirect dir feature by default"
+ depends on OVERLAY_FS
+ help
+ If this config option is enabled then overlay filesystems will use
+ redirects when renaming directories by default. In this case it is
+ still possible to turn off redirects globally with the
+ "redirect_dir=off" module option or on a filesystem instance basis
+ with the "redirect_dir=off" mount option.
+
+ Note, that redirects are not backward compatible. That is, mounting
+ an overlay which has redirects on a kernel that doesn't support this
+ feature will have unexpected results.
diff --git a/fs/overlayfs/Makefile b/fs/overlayfs/Makefile
index 900daed3e91d..99373bbc1478 100644
--- a/fs/overlayfs/Makefile
+++ b/fs/overlayfs/Makefile
@@ -4,4 +4,4 @@
obj-$(CONFIG_OVERLAY_FS) += overlay.o
-overlay-objs := super.o inode.o dir.o readdir.o copy_up.o
+overlay-objs := super.o namei.o util.o inode.o dir.o readdir.o copy_up.o
diff --git a/fs/overlayfs/copy_up.c b/fs/overlayfs/copy_up.c
index 2838bddb1f91..f57043dace62 100644
--- a/fs/overlayfs/copy_up.c
+++ b/fs/overlayfs/copy_up.c
@@ -153,6 +153,13 @@ static int ovl_copy_up_data(struct path *old, struct path *new, loff_t len)
goto out_fput;
}
+ /* Try to use clone_file_range to clone up within the same fs */
+ error = vfs_clone_file_range(old_file, 0, new_file, 0, len);
+ if (!error)
+ goto out;
+ /* Couldn't clone, so now we try to copy the data */
+ error = 0;
+
/* FIXME: copy up sparse files efficiently */
while (len) {
size_t this_len = OVL_COPY_UP_CHUNK_SIZE;
@@ -177,7 +184,7 @@ static int ovl_copy_up_data(struct path *old, struct path *new, loff_t len)
len -= bytes;
}
-
+out:
if (!error)
error = vfs_fsync(new_file, 0);
fput(new_file);
@@ -231,10 +238,15 @@ static int ovl_copy_up_locked(struct dentry *workdir, struct dentry *upperdir,
struct inode *udir = upperdir->d_inode;
struct dentry *newdentry = NULL;
struct dentry *upper = NULL;
- umode_t mode = stat->mode;
int err;
const struct cred *old_creds = NULL;
struct cred *new_creds = NULL;
+ struct cattr cattr = {
+ /* Can't properly set mode on creation because of the umask */
+ .mode = stat->mode & S_IFMT,
+ .rdev = stat->rdev,
+ .link = link
+ };
newdentry = ovl_lookup_temp(workdir, dentry);
err = PTR_ERR(newdentry);
@@ -254,10 +266,7 @@ static int ovl_copy_up_locked(struct dentry *workdir, struct dentry *upperdir,
if (new_creds)
old_creds = override_creds(new_creds);
- /* Can't properly set mode on creation because of the umask */
- stat->mode &= S_IFMT;
- err = ovl_create_real(wdir, newdentry, stat, link, NULL, true);
- stat->mode = mode;
+ err = ovl_create_real(wdir, newdentry, &cattr, NULL, true);
if (new_creds) {
revert_creds(old_creds);
@@ -296,12 +305,6 @@ static int ovl_copy_up_locked(struct dentry *workdir, struct dentry *upperdir,
ovl_dentry_update(dentry, newdentry);
ovl_inode_update(d_inode(dentry), d_inode(newdentry));
newdentry = NULL;
-
- /*
- * Non-directores become opaque when copied up.
- */
- if (!S_ISDIR(stat->mode))
- ovl_dentry_set_opaque(dentry, true);
out2:
dput(upper);
out1:
@@ -317,20 +320,14 @@ 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)
+static int ovl_copy_up_one(struct dentry *parent, struct dentry *dentry,
+ struct path *lowerpath, struct kstat *stat)
{
DEFINE_DELAYED_CALL(done);
struct dentry *workdir = ovl_workdir(dentry);
@@ -339,7 +336,6 @@ 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))
@@ -365,8 +361,7 @@ 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;
@@ -385,7 +380,7 @@ out_unlock:
return err;
}
-int ovl_copy_up(struct dentry *dentry)
+int ovl_copy_up_flags(struct dentry *dentry, int flags)
{
int err = 0;
const struct cred *old_cred = ovl_override_creds(dentry->d_sb);
@@ -415,6 +410,9 @@ int ovl_copy_up(struct dentry *dentry)
ovl_path_lower(next, &lowerpath);
err = vfs_getattr(&lowerpath, &stat);
+ /* maybe truncate regular file. this has no effect on dirs */
+ if (flags & O_TRUNC)
+ stat.size = 0;
if (!err)
err = ovl_copy_up_one(parent, next, &lowerpath, &stat);
@@ -425,3 +423,8 @@ int ovl_copy_up(struct dentry *dentry)
return err;
}
+
+int ovl_copy_up(struct dentry *dentry)
+{
+ return ovl_copy_up_flags(dentry, 0);
+}
diff --git a/fs/overlayfs/dir.c b/fs/overlayfs/dir.c
index 306b6c161840..16e06dd89457 100644
--- a/fs/overlayfs/dir.c
+++ b/fs/overlayfs/dir.c
@@ -12,11 +12,18 @@
#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;
@@ -75,8 +82,7 @@ static struct dentry *ovl_whiteout(struct dentry *workdir,
}
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;
@@ -86,13 +92,13 @@ int ovl_create_real(struct inode *dir, struct dentry *newdentry,
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:
@@ -100,11 +106,11 @@ int ovl_create_real(struct inode *dir, struct dentry *newdentry,
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:
@@ -121,20 +127,15 @@ int ovl_create_real(struct inode *dir, struct dentry *newdentry,
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,
@@ -182,9 +183,13 @@ static void ovl_instantiate(struct dentry *dentry, struct inode *inode,
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;
@@ -192,7 +197,7 @@ static int ovl_create_upper(struct dentry *dentry, struct inode *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,
@@ -200,10 +205,15 @@ static int ovl_create_upper(struct dentry *dentry, struct inode *inode,
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:
@@ -270,7 +280,8 @@ static struct dentry *ovl_clear_empty(struct dentry *dentry,
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;
@@ -278,7 +289,7 @@ static struct dentry *ovl_clear_empty(struct dentry *dentry,
if (err)
goto out_cleanup;
- err = ovl_set_opaque(opaquedir);
+ err = ovl_set_opaque(dentry, opaquedir);
if (err)
goto out_cleanup;
@@ -370,7 +381,7 @@ out_free:
}
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);
@@ -387,7 +398,7 @@ static int ovl_create_over_whiteout(struct dentry *dentry, struct inode *inode,
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;
}
@@ -407,7 +418,7 @@ static int ovl_create_over_whiteout(struct dentry *dentry, struct inode *inode,
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;
@@ -415,10 +426,11 @@ static int ovl_create_over_whiteout(struct dentry *dentry, struct inode *inode,
* 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);
@@ -438,8 +450,8 @@ static int ovl_create_over_whiteout(struct dentry *dentry, struct inode *inode,
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;
@@ -475,8 +487,7 @@ 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;
@@ -494,7 +505,7 @@ static int ovl_create_or_link(struct dentry *dentry, struct inode *inode,
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);
@@ -504,12 +515,12 @@ static int ovl_create_or_link(struct dentry *dentry, struct inode *inode,
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);
@@ -528,8 +539,9 @@ static int ovl_create_object(struct dentry *dentry, int mode, dev_t rdev,
{
int err;
struct inode *inode;
- struct kstat stat = {
+ struct cattr attr = {
.rdev = rdev,
+ .link = link,
};
err = ovl_want_write(dentry);
@@ -537,14 +549,14 @@ static int ovl_create_object(struct dentry *dentry, int mode, dev_t rdev,
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);
@@ -598,7 +610,7 @@ static int ovl_link(struct dentry *old, struct inode *newdir,
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);
@@ -684,8 +696,17 @@ static int ovl_remove_upper(struct dentry *dentry, bool is_dir)
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);
@@ -694,14 +715,15 @@ static int ovl_remove_upper(struct dentry *dentry, bool is_dir)
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
@@ -711,34 +733,21 @@ static int ovl_remove_upper(struct dentry *dentry, bool is_dir)
*/
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;
@@ -750,7 +759,7 @@ static int ovl_do_remove(struct dentry *dentry, bool is_dir)
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);
@@ -777,13 +786,114 @@ static int ovl_rmdir(struct inode *dir, struct dentry *dentry)
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;
@@ -794,7 +904,8 @@ static int ovl_rename2(struct inode *olddir, struct dentry *old,
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;
@@ -804,46 +915,12 @@ static int ovl_rename2(struct inode *olddir, struct dentry *old,
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)
@@ -862,12 +939,9 @@ static int ovl_rename2(struct inode *olddir, struct dentry *old,
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)) {
@@ -877,15 +951,15 @@ static int ovl_rename2(struct inode *olddir, struct dentry *old,
}
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;
}
@@ -896,7 +970,6 @@ static int ovl_rename2(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);
@@ -913,6 +986,9 @@ static int ovl_rename2(struct inode *olddir, struct dentry *old,
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) {
@@ -933,54 +1009,31 @@ static int ovl_rename2(struct inode *olddir, struct dentry *old,
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);
@@ -1009,7 +1062,7 @@ const struct inode_operations ovl_dir_inode_operations = {
.symlink = ovl_symlink,
.unlink = ovl_unlink,
.rmdir = ovl_rmdir,
- .rename = ovl_rename2,
+ .rename = ovl_rename,
.link = ovl_link,
.setattr = ovl_setattr,
.create = ovl_create,
diff --git a/fs/overlayfs/inode.c b/fs/overlayfs/inode.c
index 7fb53d055537..1ab8b0dbc237 100644
--- a/fs/overlayfs/inode.c
+++ b/fs/overlayfs/inode.c
@@ -13,34 +13,6 @@
#include <linux/posix_acl.h>
#include "overlayfs.h"
-static int ovl_copy_up_truncate(struct dentry *dentry)
-{
- int err;
- struct dentry *parent;
- struct kstat stat;
- struct path lowerpath;
- const struct cred *old_cred;
-
- parent = dget_parent(dentry);
- err = ovl_copy_up(parent);
- if (err)
- goto out_dput_parent;
-
- ovl_path_lower(dentry, &lowerpath);
-
- old_cred = ovl_override_creds(dentry->d_sb);
- err = vfs_getattr(&lowerpath, &stat);
- if (!err) {
- stat.size = 0;
- err = ovl_copy_up_one(parent, dentry, &lowerpath, &stat);
- }
- revert_creds(old_cred);
-
-out_dput_parent:
- dput(parent);
- return err;
-}
-
int ovl_setattr(struct dentry *dentry, struct iattr *attr)
{
int err;
@@ -64,27 +36,10 @@ int ovl_setattr(struct dentry *dentry, struct iattr *attr)
if (err)
goto out;
- if (attr->ia_valid & ATTR_SIZE) {
- struct inode *realinode = d_inode(ovl_dentry_real(dentry));
-
- err = -ETXTBSY;
- if (atomic_read(&realinode->i_writecount) < 0)
- goto out_drop_write;
- }
-
err = ovl_copy_up(dentry);
if (!err) {
- struct inode *winode = NULL;
-
upperdentry = ovl_dentry_upper(dentry);
- if (attr->ia_valid & ATTR_SIZE) {
- winode = d_inode(upperdentry);
- err = get_write_access(winode);
- if (err)
- goto out_drop_write;
- }
-
if (attr->ia_valid & (ATTR_KILL_SUID|ATTR_KILL_SGID))
attr->ia_valid &= ~ATTR_MODE;
@@ -95,11 +50,7 @@ int ovl_setattr(struct dentry *dentry, struct iattr *attr)
if (!err)
ovl_copyattr(upperdentry->d_inode, dentry->d_inode);
inode_unlock(upperdentry->d_inode);
-
- if (winode)
- put_write_access(winode);
}
-out_drop_write:
ovl_drop_write(dentry);
out:
return err;
@@ -302,10 +253,7 @@ int ovl_open_maybe_copy_up(struct dentry *dentry, unsigned int file_flags)
if (ovl_open_need_copy_up(file_flags, type, realpath.dentry)) {
err = ovl_want_write(dentry);
if (!err) {
- if (file_flags & O_TRUNC)
- err = ovl_copy_up_truncate(dentry);
- else
- err = ovl_copy_up(dentry);
+ err = ovl_copy_up_flags(dentry, file_flags);
ovl_drop_write(dentry);
}
}
@@ -354,7 +302,7 @@ static const struct inode_operations ovl_symlink_inode_operations = {
.update_time = ovl_update_time,
};
-static void ovl_fill_inode(struct inode *inode, umode_t mode)
+static void ovl_fill_inode(struct inode *inode, umode_t mode, dev_t rdev)
{
inode->i_ino = get_next_ino();
inode->i_mode = mode;
@@ -363,8 +311,11 @@ static void ovl_fill_inode(struct inode *inode, umode_t mode)
inode->i_acl = inode->i_default_acl = ACL_DONT_CACHE;
#endif
- mode &= S_IFMT;
- switch (mode) {
+ switch (mode & S_IFMT) {
+ case S_IFREG:
+ inode->i_op = &ovl_file_inode_operations;
+ break;
+
case S_IFDIR:
inode->i_op = &ovl_dir_inode_operations;
inode->i_fop = &ovl_dir_operations;
@@ -375,26 +326,19 @@ static void ovl_fill_inode(struct inode *inode, umode_t mode)
break;
default:
- WARN(1, "illegal file type: %i\n", mode);
- /* Fall through */
-
- case S_IFREG:
- case S_IFSOCK:
- case S_IFBLK:
- case S_IFCHR:
- case S_IFIFO:
inode->i_op = &ovl_file_inode_operations;
+ init_special_inode(inode, mode, rdev);
break;
}
}
-struct inode *ovl_new_inode(struct super_block *sb, umode_t mode)
+struct inode *ovl_new_inode(struct super_block *sb, umode_t mode, dev_t rdev)
{
struct inode *inode;
inode = new_inode(sb);
if (inode)
- ovl_fill_inode(inode, mode);
+ ovl_fill_inode(inode, mode, rdev);
return inode;
}
@@ -418,7 +362,7 @@ struct inode *ovl_get_inode(struct super_block *sb, struct inode *realinode)
inode = iget5_locked(sb, (unsigned long) realinode,
ovl_inode_test, ovl_inode_set, realinode);
if (inode && inode->i_state & I_NEW) {
- ovl_fill_inode(inode, realinode->i_mode);
+ ovl_fill_inode(inode, realinode->i_mode, realinode->i_rdev);
set_nlink(inode, realinode->i_nlink);
unlock_new_inode(inode);
}
diff --git a/fs/overlayfs/namei.c b/fs/overlayfs/namei.c
new file mode 100644
index 000000000000..9ad48d9202a9
--- /dev/null
+++ b/fs/overlayfs/namei.c
@@ -0,0 +1,401 @@
+/*
+ * Copyright (C) 2011 Novell Inc.
+ * Copyright (C) 2016 Red Hat, Inc.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 as published by
+ * the Free Software Foundation.
+ */
+
+#include <linux/fs.h>
+#include <linux/namei.h>
+#include <linux/xattr.h>
+#include <linux/ratelimit.h>
+#include "overlayfs.h"
+#include "ovl_entry.h"
+
+struct ovl_lookup_data {
+ struct qstr name;
+ bool is_dir;
+ bool opaque;
+ bool stop;
+ bool last;
+ char *redirect;
+};
+
+static int ovl_check_redirect(struct dentry *dentry, struct ovl_lookup_data *d,
+ size_t prelen, const char *post)
+{
+ int res;
+ char *s, *next, *buf = NULL;
+
+ res = vfs_getxattr(dentry, OVL_XATTR_REDIRECT, NULL, 0);
+ if (res < 0) {
+ if (res == -ENODATA || res == -EOPNOTSUPP)
+ return 0;
+ goto fail;
+ }
+ buf = kzalloc(prelen + res + strlen(post) + 1, GFP_TEMPORARY);
+ if (!buf)
+ return -ENOMEM;
+
+ if (res == 0)
+ goto invalid;
+
+ res = vfs_getxattr(dentry, OVL_XATTR_REDIRECT, buf, res);
+ if (res < 0)
+ goto fail;
+ if (res == 0)
+ goto invalid;
+ if (buf[0] == '/') {
+ for (s = buf; *s++ == '/'; s = next) {
+ next = strchrnul(s, '/');
+ if (s == next)
+ goto invalid;
+ }
+ } else {
+ if (strchr(buf, '/') != NULL)
+ goto invalid;
+
+ memmove(buf + prelen, buf, res);
+ memcpy(buf, d->name.name, prelen);
+ }
+
+ strcat(buf, post);
+ kfree(d->redirect);
+ d->redirect = buf;
+ d->name.name = d->redirect;
+ d->name.len = strlen(d->redirect);
+
+ return 0;
+
+err_free:
+ kfree(buf);
+ return 0;
+fail:
+ pr_warn_ratelimited("overlayfs: failed to get redirect (%i)\n", res);
+ goto err_free;
+invalid:
+ pr_warn_ratelimited("overlayfs: invalid redirect (%s)\n", buf);
+ goto err_free;
+}
+
+static bool ovl_is_opaquedir(struct dentry *dentry)
+{
+ int res;
+ char val;
+
+ if (!d_is_dir(dentry))
+ return false;
+
+ res = vfs_getxattr(dentry, OVL_XATTR_OPAQUE, &val, 1);
+ if (res == 1 && val == 'y')
+ return true;
+
+ return false;
+}
+
+static int ovl_lookup_single(struct dentry *base, struct ovl_lookup_data *d,
+ const char *name, unsigned int namelen,
+ size_t prelen, const char *post,
+ struct dentry **ret)
+{
+ struct dentry *this;
+ int err;
+
+ this = lookup_one_len_unlocked(name, base, namelen);
+ if (IS_ERR(this)) {
+ err = PTR_ERR(this);
+ this = NULL;
+ if (err == -ENOENT || err == -ENAMETOOLONG)
+ goto out;
+ goto out_err;
+ }
+ if (!this->d_inode)
+ goto put_and_out;
+
+ if (ovl_dentry_weird(this)) {
+ /* Don't support traversing automounts and other weirdness */
+ err = -EREMOTE;
+ goto out_err;
+ }
+ if (ovl_is_whiteout(this)) {
+ d->stop = d->opaque = true;
+ goto put_and_out;
+ }
+ if (!d_can_lookup(this)) {
+ d->stop = true;
+ if (d->is_dir)
+ goto put_and_out;
+ goto out;
+ }
+ d->is_dir = true;
+ if (!d->last && ovl_is_opaquedir(this)) {
+ d->stop = d->opaque = true;
+ goto out;
+ }
+ err = ovl_check_redirect(this, d, prelen, post);
+ if (err)
+ goto out_err;
+out:
+ *ret = this;
+ return 0;
+
+put_and_out:
+ dput(this);
+ this = NULL;
+ goto out;
+
+out_err:
+ dput(this);
+ return err;
+}
+
+static int ovl_lookup_layer(struct dentry *base, struct ovl_lookup_data *d,
+ struct dentry **ret)
+{
+ const char *s = d->name.name;
+ struct dentry *dentry = NULL;
+ int err;
+
+ if (*s != '/')
+ return ovl_lookup_single(base, d, d->name.name, d->name.len,
+ 0, "", ret);
+
+ while (*s++ == '/' && !IS_ERR_OR_NULL(base) && d_can_lookup(base)) {
+ const char *next = strchrnul(s, '/');
+ size_t slen = strlen(s);
+
+ if (WARN_ON(slen > d->name.len) ||
+ WARN_ON(strcmp(d->name.name + d->name.len - slen, s)))
+ return -EIO;
+
+ err = ovl_lookup_single(base, d, s, next - s,
+ d->name.len - slen, next, &base);
+ dput(dentry);
+ if (err)
+ return err;
+ dentry = base;
+ s = next;
+ }
+ *ret = dentry;
+ return 0;
+}
+
+/*
+ * Returns next layer in stack starting from top.
+ * Returns -1 if this is the last layer.
+ */
+int ovl_path_next(int idx, struct dentry *dentry, struct path *path)
+{
+ struct ovl_entry *oe = dentry->d_fsdata;
+
+ BUG_ON(idx < 0);
+ if (idx == 0) {
+ ovl_path_upper(dentry, path);
+ if (path->dentry)
+ return oe->numlower ? 1 : -1;
+ idx++;
+ }
+ BUG_ON(idx > oe->numlower);
+ *path = oe->lowerstack[idx - 1];
+
+ return (idx < oe->numlower) ? idx + 1 : -1;
+}
+
+struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry,
+ unsigned int flags)
+{
+ struct ovl_entry *oe;
+ const struct cred *old_cred;
+ struct ovl_fs *ofs = dentry->d_sb->s_fs_info;
+ struct ovl_entry *poe = dentry->d_parent->d_fsdata;
+ struct path *stack = NULL;
+ struct dentry *upperdir, *upperdentry = NULL;
+ unsigned int ctr = 0;
+ struct inode *inode = NULL;
+ bool upperopaque = false;
+ char *upperredirect = NULL;
+ struct dentry *this;
+ unsigned int i;
+ int err;
+ struct ovl_lookup_data d = {
+ .name = dentry->d_name,
+ .is_dir = false,
+ .opaque = false,
+ .stop = false,
+ .last = !poe->numlower,
+ .redirect = NULL,
+ };
+
+ if (dentry->d_name.len > ofs->namelen)
+ return ERR_PTR(-ENAMETOOLONG);
+
+ old_cred = ovl_override_creds(dentry->d_sb);
+ upperdir = ovl_upperdentry_dereference(poe);
+ if (upperdir) {
+ err = ovl_lookup_layer(upperdir, &d, &upperdentry);
+ if (err)
+ goto out;
+
+ if (upperdentry && unlikely(ovl_dentry_remote(upperdentry))) {
+ dput(upperdentry);
+ err = -EREMOTE;
+ goto out;
+ }
+
+ if (d.redirect) {
+ upperredirect = kstrdup(d.redirect, GFP_KERNEL);
+ if (!upperredirect)
+ goto out_put_upper;
+ if (d.redirect[0] == '/')
+ poe = dentry->d_sb->s_root->d_fsdata;
+ }
+ upperopaque = d.opaque;
+ }
+
+ if (!d.stop && poe->numlower) {
+ err = -ENOMEM;
+ stack = kcalloc(ofs->numlower, sizeof(struct path),
+ GFP_TEMPORARY);
+ if (!stack)
+ goto out_put_upper;
+ }
+
+ for (i = 0; !d.stop && i < poe->numlower; i++) {
+ struct path lowerpath = poe->lowerstack[i];
+
+ d.last = i == poe->numlower - 1;
+ err = ovl_lookup_layer(lowerpath.dentry, &d, &this);
+ if (err)
+ goto out_put;
+
+ if (!this)
+ continue;
+
+ stack[ctr].dentry = this;
+ stack[ctr].mnt = lowerpath.mnt;
+ ctr++;
+
+ if (d.stop)
+ break;
+
+ if (d.redirect &&
+ d.redirect[0] == '/' &&
+ poe != dentry->d_sb->s_root->d_fsdata) {
+ poe = dentry->d_sb->s_root->d_fsdata;
+
+ /* Find the current layer on the root dentry */
+ for (i = 0; i < poe->numlower; i++)
+ if (poe->lowerstack[i].mnt == lowerpath.mnt)
+ break;
+ if (WARN_ON(i == poe->numlower))
+ break;
+ }
+ }
+
+ oe = ovl_alloc_entry(ctr);
+ err = -ENOMEM;
+ if (!oe)
+ goto out_put;
+
+ if (upperdentry || ctr) {
+ struct dentry *realdentry;
+ struct inode *realinode;
+
+ realdentry = upperdentry ? upperdentry : stack[0].dentry;
+ realinode = d_inode(realdentry);
+
+ err = -ENOMEM;
+ if (upperdentry && !d_is_dir(upperdentry)) {
+ inode = ovl_get_inode(dentry->d_sb, realinode);
+ } else {
+ inode = ovl_new_inode(dentry->d_sb, realinode->i_mode,
+ realinode->i_rdev);
+ if (inode)
+ ovl_inode_init(inode, realinode, !!upperdentry);
+ }
+ if (!inode)
+ goto out_free_oe;
+ ovl_copyattr(realdentry->d_inode, inode);
+ }
+
+ revert_creds(old_cred);
+ oe->opaque = upperopaque;
+ oe->redirect = upperredirect;
+ oe->__upperdentry = upperdentry;
+ memcpy(oe->lowerstack, stack, sizeof(struct path) * ctr);
+ kfree(stack);
+ kfree(d.redirect);
+ dentry->d_fsdata = oe;
+ d_add(dentry, inode);
+
+ return NULL;
+
+out_free_oe:
+ kfree(oe);
+out_put:
+ for (i = 0; i < ctr; i++)
+ dput(stack[i].dentry);
+ kfree(stack);
+out_put_upper:
+ dput(upperdentry);
+ kfree(upperredirect);
+out:
+ kfree(d.redirect);
+ revert_creds(old_cred);
+ return ERR_PTR(err);
+}
+
+bool ovl_lower_positive(struct dentry *dentry)
+{
+ struct ovl_entry *oe = dentry->d_fsdata;
+ struct ovl_entry *poe = dentry->d_parent->d_fsdata;
+ const struct qstr *name = &dentry->d_name;
+ unsigned int i;
+ bool positive = false;
+ bool done = false;
+
+ /*
+ * If dentry is negative, then lower is positive iff this is a
+ * whiteout.
+ */
+ if (!dentry->d_inode)
+ return oe->opaque;
+
+ /* Negative upper -> positive lower */
+ if (!oe->__upperdentry)
+ return true;
+
+ /* Positive upper -> have to look up lower to see whether it exists */
+ for (i = 0; !done && !positive && i < poe->numlower; i++) {
+ struct dentry *this;
+ struct dentry *lowerdir = poe->lowerstack[i].dentry;
+
+ this = lookup_one_len_unlocked(name->name, lowerdir,
+ name->len);
+ if (IS_ERR(this)) {
+ switch (PTR_ERR(this)) {
+ case -ENOENT:
+ case -ENAMETOOLONG:
+ break;
+
+ default:
+ /*
+ * Assume something is there, we just couldn't
+ * access it.
+ */
+ positive = true;
+ break;
+ }
+ } else {
+ if (this->d_inode) {
+ positive = !ovl_is_whiteout(this);
+ done = true;
+ }
+ dput(this);
+ }
+ }
+
+ return positive;
+}
diff --git a/fs/overlayfs/overlayfs.h b/fs/overlayfs/overlayfs.h
index e218e741cb99..8af450b0e57a 100644
--- a/fs/overlayfs/overlayfs.h
+++ b/fs/overlayfs/overlayfs.h
@@ -9,23 +9,17 @@
#include <linux/kernel.h>
-struct ovl_entry;
-
enum ovl_path_type {
- __OVL_PATH_PURE = (1 << 0),
- __OVL_PATH_UPPER = (1 << 1),
- __OVL_PATH_MERGE = (1 << 2),
+ __OVL_PATH_UPPER = (1 << 0),
+ __OVL_PATH_MERGE = (1 << 1),
};
#define OVL_TYPE_UPPER(type) ((type) & __OVL_PATH_UPPER)
#define OVL_TYPE_MERGE(type) ((type) & __OVL_PATH_MERGE)
-#define OVL_TYPE_PURE_UPPER(type) ((type) & __OVL_PATH_PURE)
-#define OVL_TYPE_MERGE_OR_LOWER(type) \
- (OVL_TYPE_MERGE(type) || !OVL_TYPE_UPPER(type))
-
#define OVL_XATTR_PREFIX XATTR_TRUSTED_PREFIX "overlay."
#define OVL_XATTR_OPAQUE OVL_XATTR_PREFIX "opaque"
+#define OVL_XATTR_REDIRECT OVL_XATTR_PREFIX "redirect"
#define OVL_ISUPPER_MASK 1UL
@@ -143,35 +137,43 @@ static inline struct inode *ovl_inode_real(struct inode *inode, bool *is_upper)
return (struct inode *) (x & ~OVL_ISUPPER_MASK);
}
+/* util.c */
+int ovl_want_write(struct dentry *dentry);
+void ovl_drop_write(struct dentry *dentry);
+struct dentry *ovl_workdir(struct dentry *dentry);
+const struct cred *ovl_override_creds(struct super_block *sb);
+struct ovl_entry *ovl_alloc_entry(unsigned int numlower);
+bool ovl_dentry_remote(struct dentry *dentry);
+bool ovl_dentry_weird(struct dentry *dentry);
enum ovl_path_type ovl_path_type(struct dentry *dentry);
-u64 ovl_dentry_version_get(struct dentry *dentry);
-void ovl_dentry_version_inc(struct dentry *dentry);
void ovl_path_upper(struct dentry *dentry, struct path *path);
void ovl_path_lower(struct dentry *dentry, struct path *path);
enum ovl_path_type ovl_path_real(struct dentry *dentry, struct path *path);
-int ovl_path_next(int idx, struct dentry *dentry, struct path *path);
struct dentry *ovl_dentry_upper(struct dentry *dentry);
struct dentry *ovl_dentry_lower(struct dentry *dentry);
struct dentry *ovl_dentry_real(struct dentry *dentry);
-struct vfsmount *ovl_entry_mnt_real(struct ovl_entry *oe, struct inode *inode,
- bool is_upper);
struct ovl_dir_cache *ovl_dir_cache(struct dentry *dentry);
void ovl_set_dir_cache(struct dentry *dentry, struct ovl_dir_cache *cache);
-struct dentry *ovl_workdir(struct dentry *dentry);
-int ovl_want_write(struct dentry *dentry);
-void ovl_drop_write(struct dentry *dentry);
bool ovl_dentry_is_opaque(struct dentry *dentry);
-void ovl_dentry_set_opaque(struct dentry *dentry, bool opaque);
-bool ovl_is_whiteout(struct dentry *dentry);
-const struct cred *ovl_override_creds(struct super_block *sb);
+bool ovl_dentry_is_whiteout(struct dentry *dentry);
+void ovl_dentry_set_opaque(struct dentry *dentry);
+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);
void ovl_inode_update(struct inode *inode, struct inode *upperinode);
-struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry,
- unsigned int flags);
+void ovl_dentry_version_inc(struct dentry *dentry);
+u64 ovl_dentry_version_get(struct dentry *dentry);
+bool ovl_is_whiteout(struct dentry *dentry);
struct file *ovl_path_open(struct path *path, int flags);
-struct dentry *ovl_upper_create(struct dentry *upperdir, struct dentry *dentry,
- struct kstat *stat, const char *link);
+/* namei.c */
+int ovl_path_next(int idx, struct dentry *dentry, struct path *path);
+struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags);
+bool ovl_lower_positive(struct dentry *dentry);
/* readdir.c */
extern const struct file_operations ovl_dir_operations;
@@ -195,7 +197,7 @@ int ovl_open_maybe_copy_up(struct dentry *dentry, unsigned int file_flags);
int ovl_update_time(struct inode *inode, struct timespec *ts, int flags);
bool ovl_is_private_xattr(const char *name);
-struct inode *ovl_new_inode(struct super_block *sb, umode_t mode);
+struct inode *ovl_new_inode(struct super_block *sb, umode_t mode, dev_t rdev);
struct inode *ovl_get_inode(struct super_block *sb, struct inode *realinode);
static inline void ovl_copyattr(struct inode *from, struct inode *to)
{
@@ -210,14 +212,18 @@ static inline void ovl_copyattr(struct inode *from, struct inode *to)
/* dir.c */
extern const struct inode_operations ovl_dir_inode_operations;
struct dentry *ovl_lookup_temp(struct dentry *workdir, struct dentry *dentry);
+struct cattr {
+ dev_t rdev;
+ umode_t mode;
+ const char *link;
+};
int ovl_create_real(struct inode *dir, struct dentry *newdentry,
- struct kstat *stat, const char *link,
+ struct cattr *attr,
struct dentry *hardlink, bool debug);
void ovl_cleanup(struct inode *dir, struct dentry *dentry);
/* copy_up.c */
int ovl_copy_up(struct dentry *dentry);
-int ovl_copy_up_one(struct dentry *parent, struct dentry *dentry,
- struct path *lowerpath, struct kstat *stat);
+int ovl_copy_up_flags(struct dentry *dentry, int flags);
int ovl_copy_xattr(struct dentry *old, struct dentry *new);
int ovl_set_attr(struct dentry *upper, struct kstat *stat);
diff --git a/fs/overlayfs/ovl_entry.h b/fs/overlayfs/ovl_entry.h
new file mode 100644
index 000000000000..d14bca1850d9
--- /dev/null
+++ b/fs/overlayfs/ovl_entry.h
@@ -0,0 +1,53 @@
+/*
+ *
+ * Copyright (C) 2011 Novell Inc.
+ * Copyright (C) 2016 Red Hat, Inc.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 as published by
+ * the Free Software Foundation.
+ */
+
+struct ovl_config {
+ char *lowerdir;
+ char *upperdir;
+ char *workdir;
+ bool default_permissions;
+ bool redirect_dir;
+};
+
+/* private information held for overlayfs's superblock */
+struct ovl_fs {
+ struct vfsmount *upper_mnt;
+ unsigned numlower;
+ struct vfsmount **lower_mnt;
+ struct dentry *workdir;
+ long namelen;
+ /* pathnames of lower and upper dirs, for show_options */
+ struct ovl_config config;
+ /* creds of process who forced instantiation of super block */
+ const struct cred *creator_cred;
+};
+
+/* private information held for every overlayfs dentry */
+struct ovl_entry {
+ struct dentry *__upperdentry;
+ struct ovl_dir_cache *cache;
+ union {
+ struct {
+ u64 version;
+ const char *redirect;
+ bool opaque;
+ };
+ struct rcu_head rcu;
+ };
+ unsigned numlower;
+ struct path lowerstack[];
+};
+
+struct ovl_entry *ovl_alloc_entry(unsigned int numlower);
+
+static inline struct dentry *ovl_upperdentry_dereference(struct ovl_entry *oe)
+{
+ return lockless_dereference(oe->__upperdentry);
+}
diff --git a/fs/overlayfs/super.c b/fs/overlayfs/super.c
index 0e100856c7b8..20f48abbb82f 100644
--- a/fs/overlayfs/super.c
+++ b/fs/overlayfs/super.c
@@ -9,280 +9,29 @@
#include <linux/fs.h>
#include <linux/namei.h>
-#include <linux/pagemap.h>
#include <linux/xattr.h>
-#include <linux/security.h>
#include <linux/mount.h>
-#include <linux/slab.h>
#include <linux/parser.h>
#include <linux/module.h>
-#include <linux/sched.h>
#include <linux/statfs.h>
#include <linux/seq_file.h>
#include <linux/posix_acl_xattr.h>
#include "overlayfs.h"
+#include "ovl_entry.h"
MODULE_AUTHOR("Miklos Szeredi <miklos@szeredi.hu>");
MODULE_DESCRIPTION("Overlay filesystem");
MODULE_LICENSE("GPL");
-struct ovl_config {
- char *lowerdir;
- char *upperdir;
- char *workdir;
- bool default_permissions;
-};
-
-/* private information held for overlayfs's superblock */
-struct ovl_fs {
- struct vfsmount *upper_mnt;
- unsigned numlower;
- struct vfsmount **lower_mnt;
- struct dentry *workdir;
- long lower_namelen;
- /* pathnames of lower and upper dirs, for show_options */
- struct ovl_config config;
- /* creds of process who forced instantiation of super block */
- const struct cred *creator_cred;
-};
struct ovl_dir_cache;
-/* private information held for every overlayfs dentry */
-struct ovl_entry {
- struct dentry *__upperdentry;
- struct ovl_dir_cache *cache;
- union {
- struct {
- u64 version;
- bool opaque;
- };
- struct rcu_head rcu;
- };
- unsigned numlower;
- struct path lowerstack[];
-};
-
#define OVL_MAX_STACK 500
-static struct dentry *__ovl_dentry_lower(struct ovl_entry *oe)
-{
- return oe->numlower ? oe->lowerstack[0].dentry : NULL;
-}
-
-enum ovl_path_type ovl_path_type(struct dentry *dentry)
-{
- struct ovl_entry *oe = dentry->d_fsdata;
- enum ovl_path_type type = 0;
-
- if (oe->__upperdentry) {
- type = __OVL_PATH_UPPER;
-
- /*
- * Non-dir dentry can hold lower dentry from previous
- * location. Its purity depends only on opaque flag.
- */
- if (oe->numlower && S_ISDIR(dentry->d_inode->i_mode))
- type |= __OVL_PATH_MERGE;
- else if (!oe->opaque)
- type |= __OVL_PATH_PURE;
- } else {
- if (oe->numlower > 1)
- type |= __OVL_PATH_MERGE;
- }
- return type;
-}
-
-static struct dentry *ovl_upperdentry_dereference(struct ovl_entry *oe)
-{
- return lockless_dereference(oe->__upperdentry);
-}
-
-void ovl_path_upper(struct dentry *dentry, struct path *path)
-{
- struct ovl_fs *ofs = dentry->d_sb->s_fs_info;
- struct ovl_entry *oe = dentry->d_fsdata;
-
- path->mnt = ofs->upper_mnt;
- path->dentry = ovl_upperdentry_dereference(oe);
-}
-
-enum ovl_path_type ovl_path_real(struct dentry *dentry, struct path *path)
-{
- enum ovl_path_type type = ovl_path_type(dentry);
-
- if (!OVL_TYPE_UPPER(type))
- ovl_path_lower(dentry, path);
- else
- ovl_path_upper(dentry, path);
-
- return type;
-}
-
-struct dentry *ovl_dentry_upper(struct dentry *dentry)
-{
- struct ovl_entry *oe = dentry->d_fsdata;
-
- return ovl_upperdentry_dereference(oe);
-}
-
-struct dentry *ovl_dentry_lower(struct dentry *dentry)
-{
- struct ovl_entry *oe = dentry->d_fsdata;
-
- return __ovl_dentry_lower(oe);
-}
-
-struct dentry *ovl_dentry_real(struct dentry *dentry)
-{
- struct ovl_entry *oe = dentry->d_fsdata;
- struct dentry *realdentry;
-
- realdentry = ovl_upperdentry_dereference(oe);
- if (!realdentry)
- realdentry = __ovl_dentry_lower(oe);
-
- return realdentry;
-}
-
-static void ovl_inode_init(struct inode *inode, struct inode *realinode,
- bool is_upper)
-{
- WRITE_ONCE(inode->i_private, (unsigned long) realinode |
- (is_upper ? OVL_ISUPPER_MASK : 0));
-}
-
-struct vfsmount *ovl_entry_mnt_real(struct ovl_entry *oe, struct inode *inode,
- bool is_upper)
-{
- if (is_upper) {
- struct ovl_fs *ofs = inode->i_sb->s_fs_info;
-
- return ofs->upper_mnt;
- } else {
- return oe->numlower ? oe->lowerstack[0].mnt : NULL;
- }
-}
-
-struct ovl_dir_cache *ovl_dir_cache(struct dentry *dentry)
-{
- struct ovl_entry *oe = dentry->d_fsdata;
-
- return oe->cache;
-}
-
-void ovl_set_dir_cache(struct dentry *dentry, struct ovl_dir_cache *cache)
-{
- struct ovl_entry *oe = dentry->d_fsdata;
-
- oe->cache = cache;
-}
-
-void ovl_path_lower(struct dentry *dentry, struct path *path)
-{
- struct ovl_entry *oe = dentry->d_fsdata;
-
- *path = oe->numlower ? oe->lowerstack[0] : (struct path) { NULL, NULL };
-}
-
-int ovl_want_write(struct dentry *dentry)
-{
- struct ovl_fs *ofs = dentry->d_sb->s_fs_info;
- return mnt_want_write(ofs->upper_mnt);
-}
-
-void ovl_drop_write(struct dentry *dentry)
-{
- struct ovl_fs *ofs = dentry->d_sb->s_fs_info;
- mnt_drop_write(ofs->upper_mnt);
-}
-
-struct dentry *ovl_workdir(struct dentry *dentry)
-{
- struct ovl_fs *ofs = dentry->d_sb->s_fs_info;
- return ofs->workdir;
-}
-
-bool ovl_dentry_is_opaque(struct dentry *dentry)
-{
- struct ovl_entry *oe = dentry->d_fsdata;
- return oe->opaque;
-}
-
-void ovl_dentry_set_opaque(struct dentry *dentry, bool opaque)
-{
- struct ovl_entry *oe = dentry->d_fsdata;
- oe->opaque = opaque;
-}
-
-void ovl_dentry_update(struct dentry *dentry, struct dentry *upperdentry)
-{
- struct ovl_entry *oe = dentry->d_fsdata;
-
- WARN_ON(!inode_is_locked(upperdentry->d_parent->d_inode));
- WARN_ON(oe->__upperdentry);
- /*
- * Make sure upperdentry is consistent before making it visible to
- * ovl_upperdentry_dereference().
- */
- smp_wmb();
- oe->__upperdentry = upperdentry;
-}
-
-void ovl_inode_update(struct inode *inode, struct inode *upperinode)
-{
- WARN_ON(!upperinode);
- WARN_ON(!inode_unhashed(inode));
- WRITE_ONCE(inode->i_private,
- (unsigned long) upperinode | OVL_ISUPPER_MASK);
- if (!S_ISDIR(upperinode->i_mode))
- __insert_inode_hash(inode, (unsigned long) upperinode);
-}
-
-void ovl_dentry_version_inc(struct dentry *dentry)
-{
- struct ovl_entry *oe = dentry->d_fsdata;
-
- WARN_ON(!inode_is_locked(dentry->d_inode));
- oe->version++;
-}
-
-u64 ovl_dentry_version_get(struct dentry *dentry)
-{
- struct ovl_entry *oe = dentry->d_fsdata;
-
- WARN_ON(!inode_is_locked(dentry->d_inode));
- return oe->version;
-}
-
-bool ovl_is_whiteout(struct dentry *dentry)
-{
- struct inode *inode = dentry->d_inode;
-
- return inode && IS_WHITEOUT(inode);
-}
-
-const struct cred *ovl_override_creds(struct super_block *sb)
-{
- struct ovl_fs *ofs = sb->s_fs_info;
-
- return override_creds(ofs->creator_cred);
-}
-
-static bool ovl_is_opaquedir(struct dentry *dentry)
-{
- int res;
- char val;
-
- if (!d_is_dir(dentry))
- return false;
-
- res = vfs_getxattr(dentry, OVL_XATTR_OPAQUE, &val, 1);
- if (res == 1 && val == 'y')
- return true;
-
- return false;
-}
+static bool ovl_redirect_dir_def = IS_ENABLED(CONFIG_OVERLAY_FS_REDIRECT_DIR);
+module_param_named(redirect_dir, ovl_redirect_dir_def, bool, 0644);
+MODULE_PARM_DESC(ovl_redirect_dir_def,
+ "Default to on or off for the redirect_dir feature");
static void ovl_dentry_release(struct dentry *dentry)
{
@@ -292,6 +41,7 @@ static void ovl_dentry_release(struct dentry *dentry)
unsigned int i;
dput(oe->__upperdentry);
+ kfree(oe->redirect);
for (i = 0; i < oe->numlower; i++)
dput(oe->lowerstack[i].dentry);
kfree_rcu(oe, rcu);
@@ -304,7 +54,7 @@ static struct dentry *ovl_d_real(struct dentry *dentry,
{
struct dentry *real;
- if (d_is_dir(dentry)) {
+ if (!d_is_reg(dentry)) {
if (!inode || inode == d_inode(dentry))
return dentry;
goto bug;
@@ -392,226 +142,6 @@ static const struct dentry_operations ovl_reval_dentry_operations = {
.d_weak_revalidate = ovl_dentry_weak_revalidate,
};
-static struct ovl_entry *ovl_alloc_entry(unsigned int numlower)
-{
- size_t size = offsetof(struct ovl_entry, lowerstack[numlower]);
- struct ovl_entry *oe = kzalloc(size, GFP_KERNEL);
-
- if (oe)
- oe->numlower = numlower;
-
- return oe;
-}
-
-static bool ovl_dentry_remote(struct dentry *dentry)
-{
- return dentry->d_flags &
- (DCACHE_OP_REVALIDATE | DCACHE_OP_WEAK_REVALIDATE |
- DCACHE_OP_REAL);
-}
-
-static bool ovl_dentry_weird(struct dentry *dentry)
-{
- return dentry->d_flags & (DCACHE_NEED_AUTOMOUNT |
- DCACHE_MANAGE_TRANSIT |
- DCACHE_OP_HASH |
- DCACHE_OP_COMPARE);
-}
-
-static inline struct dentry *ovl_lookup_real(struct dentry *dir,
- const struct qstr *name)
-{
- struct dentry *dentry;
-
- dentry = lookup_one_len_unlocked(name->name, dir, name->len);
-
- if (IS_ERR(dentry)) {
- if (PTR_ERR(dentry) == -ENOENT)
- dentry = NULL;
- } else if (!dentry->d_inode) {
- dput(dentry);
- dentry = NULL;
- } else if (ovl_dentry_weird(dentry)) {
- dput(dentry);
- /* Don't support traversing automounts and other weirdness */
- dentry = ERR_PTR(-EREMOTE);
- }
- return dentry;
-}
-
-/*
- * Returns next layer in stack starting from top.
- * Returns -1 if this is the last layer.
- */
-int ovl_path_next(int idx, struct dentry *dentry, struct path *path)
-{
- struct ovl_entry *oe = dentry->d_fsdata;
-
- BUG_ON(idx < 0);
- if (idx == 0) {
- ovl_path_upper(dentry, path);
- if (path->dentry)
- return oe->numlower ? 1 : -1;
- idx++;
- }
- BUG_ON(idx > oe->numlower);
- *path = oe->lowerstack[idx - 1];
-
- return (idx < oe->numlower) ? idx + 1 : -1;
-}
-
-struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry,
- unsigned int flags)
-{
- struct ovl_entry *oe;
- const struct cred *old_cred;
- struct ovl_entry *poe = dentry->d_parent->d_fsdata;
- struct path *stack = NULL;
- struct dentry *upperdir, *upperdentry = NULL;
- unsigned int ctr = 0;
- struct inode *inode = NULL;
- bool upperopaque = false;
- struct dentry *this, *prev = NULL;
- unsigned int i;
- int err;
-
- old_cred = ovl_override_creds(dentry->d_sb);
- upperdir = ovl_upperdentry_dereference(poe);
- if (upperdir) {
- this = ovl_lookup_real(upperdir, &dentry->d_name);
- err = PTR_ERR(this);
- if (IS_ERR(this))
- goto out;
-
- if (this) {
- if (unlikely(ovl_dentry_remote(this))) {
- dput(this);
- err = -EREMOTE;
- goto out;
- }
- if (ovl_is_whiteout(this)) {
- dput(this);
- this = NULL;
- upperopaque = true;
- } else if (poe->numlower && ovl_is_opaquedir(this)) {
- upperopaque = true;
- }
- }
- upperdentry = prev = this;
- }
-
- if (!upperopaque && poe->numlower) {
- err = -ENOMEM;
- stack = kcalloc(poe->numlower, sizeof(struct path), GFP_KERNEL);
- if (!stack)
- goto out_put_upper;
- }
-
- for (i = 0; !upperopaque && i < poe->numlower; i++) {
- bool opaque = false;
- struct path lowerpath = poe->lowerstack[i];
-
- this = ovl_lookup_real(lowerpath.dentry, &dentry->d_name);
- err = PTR_ERR(this);
- if (IS_ERR(this)) {
- /*
- * If it's positive, then treat ENAMETOOLONG as ENOENT.
- */
- if (err == -ENAMETOOLONG && (upperdentry || ctr))
- continue;
- goto out_put;
- }
- if (!this)
- continue;
- if (ovl_is_whiteout(this)) {
- dput(this);
- break;
- }
- /*
- * Only makes sense to check opaque dir if this is not the
- * lowermost layer.
- */
- if (i < poe->numlower - 1 && ovl_is_opaquedir(this))
- opaque = true;
-
- if (prev && (!S_ISDIR(prev->d_inode->i_mode) ||
- !S_ISDIR(this->d_inode->i_mode))) {
- /*
- * FIXME: check for upper-opaqueness maybe better done
- * in remove code.
- */
- if (prev == upperdentry)
- upperopaque = true;
- dput(this);
- break;
- }
- /*
- * If this is a non-directory then stop here.
- */
- if (!S_ISDIR(this->d_inode->i_mode))
- opaque = true;
-
- stack[ctr].dentry = this;
- stack[ctr].mnt = lowerpath.mnt;
- ctr++;
- prev = this;
- if (opaque)
- break;
- }
-
- oe = ovl_alloc_entry(ctr);
- err = -ENOMEM;
- if (!oe)
- goto out_put;
-
- if (upperdentry || ctr) {
- struct dentry *realdentry;
- struct inode *realinode;
-
- realdentry = upperdentry ? upperdentry : stack[0].dentry;
- realinode = d_inode(realdentry);
-
- err = -ENOMEM;
- if (upperdentry && !d_is_dir(upperdentry)) {
- inode = ovl_get_inode(dentry->d_sb, realinode);
- } else {
- inode = ovl_new_inode(dentry->d_sb, realinode->i_mode);
- if (inode)
- ovl_inode_init(inode, realinode, !!upperdentry);
- }
- if (!inode)
- goto out_free_oe;
- ovl_copyattr(realdentry->d_inode, inode);
- }
-
- revert_creds(old_cred);
- oe->opaque = upperopaque;
- oe->__upperdentry = upperdentry;
- memcpy(oe->lowerstack, stack, sizeof(struct path) * ctr);
- kfree(stack);
- dentry->d_fsdata = oe;
- d_add(dentry, inode);
-
- return NULL;
-
-out_free_oe:
- kfree(oe);
-out_put:
- for (i = 0; i < ctr; i++)
- dput(stack[i].dentry);
- kfree(stack);
-out_put_upper:
- dput(upperdentry);
-out:
- revert_creds(old_cred);
- return ERR_PTR(err);
-}
-
-struct file *ovl_path_open(struct path *path, int flags)
-{
- return dentry_open(path, flags | O_NOATIME, current_cred());
-}
-
static void ovl_put_super(struct super_block *sb)
{
struct ovl_fs *ufs = sb->s_fs_info;
@@ -649,7 +179,7 @@ static int ovl_statfs(struct dentry *dentry, struct kstatfs *buf)
err = vfs_statfs(&path, buf);
if (!err) {
- buf->f_namelen = max(buf->f_namelen, ofs->lower_namelen);
+ buf->f_namelen = ofs->namelen;
buf->f_type = OVERLAYFS_SUPER_MAGIC;
}
@@ -674,6 +204,9 @@ static int ovl_show_options(struct seq_file *m, struct dentry *dentry)
}
if (ufs->config.default_permissions)
seq_puts(m, ",default_permissions");
+ if (ufs->config.redirect_dir != ovl_redirect_dir_def)
+ seq_printf(m, ",redirect_dir=%s",
+ ufs->config.redirect_dir ? "on" : "off");
return 0;
}
@@ -700,6 +233,8 @@ enum {
OPT_UPPERDIR,
OPT_WORKDIR,
OPT_DEFAULT_PERMISSIONS,
+ OPT_REDIRECT_DIR_ON,
+ OPT_REDIRECT_DIR_OFF,
OPT_ERR,
};
@@ -708,6 +243,8 @@ 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}
};
@@ -772,6 +309,14 @@ 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;
@@ -809,12 +354,9 @@ retry:
strlen(OVL_WORKDIR_NAME));
if (!IS_ERR(work)) {
- struct kstat stat = {
- .mode = S_IFDIR | 0,
- };
struct iattr attr = {
.ia_valid = ATTR_MODE,
- .ia_mode = stat.mode,
+ .ia_mode = S_IFDIR | 0,
};
if (work->d_inode) {
@@ -828,7 +370,9 @@ retry:
goto retry;
}
- err = ovl_create_real(dir, work, &stat, NULL, NULL, true);
+ err = ovl_create_real(dir, work,
+ &(struct cattr){.mode = S_IFDIR | 0},
+ NULL, true);
if (err)
goto out_dput;
@@ -903,7 +447,7 @@ static int ovl_mount_dir_noesc(const char *name, struct path *path)
pr_err("overlayfs: filesystem on '%s' not supported\n", name);
goto out_put;
}
- if (!S_ISDIR(path->dentry->d_inode->i_mode)) {
+ if (!d_is_dir(path->dentry)) {
pr_err("overlayfs: '%s' not a directory\n", name);
goto out_put;
}
@@ -936,22 +480,33 @@ static int ovl_mount_dir(const char *name, struct path *path)
return err;
}
-static int ovl_lower_dir(const char *name, struct path *path, long *namelen,
- int *stack_depth, bool *remote)
+static int ovl_check_namelen(struct path *path, struct ovl_fs *ofs,
+ const char *name)
{
- int err;
struct kstatfs statfs;
+ int err = vfs_statfs(path, &statfs);
+
+ if (err)
+ pr_err("overlayfs: statfs failed on '%s'\n", name);
+ else
+ ofs->namelen = max(ofs->namelen, statfs.f_namelen);
+
+ return err;
+}
+
+static int ovl_lower_dir(const char *name, struct path *path,
+ struct ovl_fs *ofs, int *stack_depth, bool *remote)
+{
+ int err;
err = ovl_mount_dir_noesc(name, path);
if (err)
goto out;
- err = vfs_statfs(path, &statfs);
- if (err) {
- pr_err("overlayfs: statfs failed on '%s'\n", name);
+ err = ovl_check_namelen(path, ofs, name);
+ if (err)
goto out_put;
- }
- *namelen = max(*namelen, statfs.f_namelen);
+
*stack_depth = max(*stack_depth, path->mnt->mnt_sb->s_stack_depth);
if (ovl_dentry_remote(path->dentry))
@@ -1067,7 +622,7 @@ static int ovl_own_xattr_get(const struct xattr_handler *handler,
struct dentry *dentry, struct inode *inode,
const char *name, void *buffer, size_t size)
{
- return -EPERM;
+ return -EOPNOTSUPP;
}
static int ovl_own_xattr_set(const struct xattr_handler *handler,
@@ -1075,7 +630,7 @@ static int ovl_own_xattr_set(const struct xattr_handler *handler,
const char *name, const void *value,
size_t size, int flags)
{
- return -EPERM;
+ return -EOPNOTSUPP;
}
static int ovl_other_xattr_get(const struct xattr_handler *handler,
@@ -1153,6 +708,7 @@ static int ovl_fill_super(struct super_block *sb, void *data, int silent)
if (!ufs)
goto out;
+ ufs->config.redirect_dir = ovl_redirect_dir_def;
err = ovl_parse_opt((char *) data, &ufs->config);
if (err)
goto out_free_config;
@@ -1183,6 +739,10 @@ static int ovl_fill_super(struct super_block *sb, void *data, int silent)
goto out_put_upperpath;
}
+ err = ovl_check_namelen(&upperpath, ufs, ufs->config.upperdir);
+ if (err)
+ goto out_put_upperpath;
+
err = ovl_mount_dir(ufs->config.workdir, &workpath);
if (err)
goto out_put_upperpath;
@@ -1214,15 +774,16 @@ static int ovl_fill_super(struct super_block *sb, void *data, int silent)
goto out_free_lowertmp;
}
+ err = -ENOMEM;
stack = kcalloc(stacklen, sizeof(struct path), GFP_KERNEL);
if (!stack)
goto out_free_lowertmp;
+ err = -EINVAL;
lower = lowertmp;
for (numlower = 0; numlower < stacklen; numlower++) {
- err = ovl_lower_dir(lower, &stack[numlower],
- &ufs->lower_namelen, &sb->s_stack_depth,
- &remote);
+ err = ovl_lower_dir(lower, &stack[numlower], ufs,
+ &sb->s_stack_depth, &remote);
if (err)
goto out_put_lowerpath;
@@ -1324,7 +885,7 @@ static int ovl_fill_super(struct super_block *sb, void *data, int silent)
sb->s_fs_info = ufs;
sb->s_flags |= MS_POSIXACL | MS_NOREMOTELOCK;
- root_dentry = d_make_root(ovl_new_inode(sb, S_IFDIR));
+ root_dentry = d_make_root(ovl_new_inode(sb, S_IFDIR, 0));
if (!root_dentry)
goto out_free_oe;
diff --git a/fs/overlayfs/util.c b/fs/overlayfs/util.c
new file mode 100644
index 000000000000..952286f4826c
--- /dev/null
+++ b/fs/overlayfs/util.c
@@ -0,0 +1,265 @@
+/*
+ * Copyright (C) 2011 Novell Inc.
+ * Copyright (C) 2016 Red Hat, Inc.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 as published by
+ * the Free Software Foundation.
+ */
+
+#include <linux/fs.h>
+#include <linux/mount.h>
+#include <linux/slab.h>
+#include <linux/xattr.h>
+#include "overlayfs.h"
+#include "ovl_entry.h"
+
+int ovl_want_write(struct dentry *dentry)
+{
+ struct ovl_fs *ofs = dentry->d_sb->s_fs_info;
+ return mnt_want_write(ofs->upper_mnt);
+}
+
+void ovl_drop_write(struct dentry *dentry)
+{
+ struct ovl_fs *ofs = dentry->d_sb->s_fs_info;
+ mnt_drop_write(ofs->upper_mnt);
+}
+
+struct dentry *ovl_workdir(struct dentry *dentry)
+{
+ struct ovl_fs *ofs = dentry->d_sb->s_fs_info;
+ return ofs->workdir;
+}
+
+const struct cred *ovl_override_creds(struct super_block *sb)
+{
+ struct ovl_fs *ofs = sb->s_fs_info;
+
+ return override_creds(ofs->creator_cred);
+}
+
+struct ovl_entry *ovl_alloc_entry(unsigned int numlower)
+{
+ size_t size = offsetof(struct ovl_entry, lowerstack[numlower]);
+ struct ovl_entry *oe = kzalloc(size, GFP_KERNEL);
+
+ if (oe)
+ oe->numlower = numlower;
+
+ return oe;
+}
+
+bool ovl_dentry_remote(struct dentry *dentry)
+{
+ return dentry->d_flags &
+ (DCACHE_OP_REVALIDATE | DCACHE_OP_WEAK_REVALIDATE |
+ DCACHE_OP_REAL);
+}
+
+bool ovl_dentry_weird(struct dentry *dentry)
+{
+ return dentry->d_flags & (DCACHE_NEED_AUTOMOUNT |
+ DCACHE_MANAGE_TRANSIT |
+ DCACHE_OP_HASH |
+ DCACHE_OP_COMPARE);
+}
+
+enum ovl_path_type ovl_path_type(struct dentry *dentry)
+{
+ struct ovl_entry *oe = dentry->d_fsdata;
+ enum ovl_path_type type = 0;
+
+ if (oe->__upperdentry) {
+ type = __OVL_PATH_UPPER;
+
+ /*
+ * Non-dir dentry can hold lower dentry from previous
+ * location.
+ */
+ if (oe->numlower && d_is_dir(dentry))
+ type |= __OVL_PATH_MERGE;
+ } else {
+ if (oe->numlower > 1)
+ type |= __OVL_PATH_MERGE;
+ }
+ return type;
+}
+
+void ovl_path_upper(struct dentry *dentry, struct path *path)
+{
+ struct ovl_fs *ofs = dentry->d_sb->s_fs_info;
+ struct ovl_entry *oe = dentry->d_fsdata;
+
+ path->mnt = ofs->upper_mnt;
+ path->dentry = ovl_upperdentry_dereference(oe);
+}
+
+void ovl_path_lower(struct dentry *dentry, struct path *path)
+{
+ struct ovl_entry *oe = dentry->d_fsdata;
+
+ *path = oe->numlower ? oe->lowerstack[0] : (struct path) { NULL, NULL };
+}
+
+enum ovl_path_type ovl_path_real(struct dentry *dentry, struct path *path)
+{
+ enum ovl_path_type type = ovl_path_type(dentry);
+
+ if (!OVL_TYPE_UPPER(type))
+ ovl_path_lower(dentry, path);
+ else
+ ovl_path_upper(dentry, path);
+
+ return type;
+}
+
+struct dentry *ovl_dentry_upper(struct dentry *dentry)
+{
+ struct ovl_entry *oe = dentry->d_fsdata;
+
+ return ovl_upperdentry_dereference(oe);
+}
+
+static struct dentry *__ovl_dentry_lower(struct ovl_entry *oe)
+{
+ return oe->numlower ? oe->lowerstack[0].dentry : NULL;
+}
+
+struct dentry *ovl_dentry_lower(struct dentry *dentry)
+{
+ struct ovl_entry *oe = dentry->d_fsdata;
+
+ return __ovl_dentry_lower(oe);
+}
+
+struct dentry *ovl_dentry_real(struct dentry *dentry)
+{
+ struct ovl_entry *oe = dentry->d_fsdata;
+ struct dentry *realdentry;
+
+ realdentry = ovl_upperdentry_dereference(oe);
+ if (!realdentry)
+ realdentry = __ovl_dentry_lower(oe);
+
+ return realdentry;
+}
+
+struct ovl_dir_cache *ovl_dir_cache(struct dentry *dentry)
+{
+ struct ovl_entry *oe = dentry->d_fsdata;
+
+ return oe->cache;
+}
+
+void ovl_set_dir_cache(struct dentry *dentry, struct ovl_dir_cache *cache)
+{
+ struct ovl_entry *oe = dentry->d_fsdata;
+
+ oe->cache = cache;
+}
+
+bool ovl_dentry_is_opaque(struct dentry *dentry)
+{
+ struct ovl_entry *oe = dentry->d_fsdata;
+ return oe->opaque;
+}
+
+bool ovl_dentry_is_whiteout(struct dentry *dentry)
+{
+ return !dentry->d_inode && ovl_dentry_is_opaque(dentry);
+}
+
+void ovl_dentry_set_opaque(struct dentry *dentry)
+{
+ struct ovl_entry *oe = dentry->d_fsdata;
+
+ oe->opaque = true;
+}
+
+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;
+
+ WARN_ON(!inode_is_locked(upperdentry->d_parent->d_inode));
+ WARN_ON(oe->__upperdentry);
+ /*
+ * Make sure upperdentry is consistent before making it visible to
+ * ovl_upperdentry_dereference().
+ */
+ smp_wmb();
+ oe->__upperdentry = upperdentry;
+}
+
+void ovl_inode_init(struct inode *inode, struct inode *realinode, bool is_upper)
+{
+ WRITE_ONCE(inode->i_private, (unsigned long) realinode |
+ (is_upper ? OVL_ISUPPER_MASK : 0));
+}
+
+void ovl_inode_update(struct inode *inode, struct inode *upperinode)
+{
+ WARN_ON(!upperinode);
+ WARN_ON(!inode_unhashed(inode));
+ WRITE_ONCE(inode->i_private,
+ (unsigned long) upperinode | OVL_ISUPPER_MASK);
+ if (!S_ISDIR(upperinode->i_mode))
+ __insert_inode_hash(inode, (unsigned long) upperinode);
+}
+
+void ovl_dentry_version_inc(struct dentry *dentry)
+{
+ struct ovl_entry *oe = dentry->d_fsdata;
+
+ WARN_ON(!inode_is_locked(dentry->d_inode));
+ oe->version++;
+}
+
+u64 ovl_dentry_version_get(struct dentry *dentry)
+{
+ struct ovl_entry *oe = dentry->d_fsdata;
+
+ WARN_ON(!inode_is_locked(dentry->d_inode));
+ return oe->version;
+}
+
+bool ovl_is_whiteout(struct dentry *dentry)
+{
+ struct inode *inode = dentry->d_inode;
+
+ return inode && IS_WHITEOUT(inode);
+}
+
+struct file *ovl_path_open(struct path *path, int flags)
+{
+ return dentry_open(path, flags | O_NOATIME, current_cred());
+}