mount -t overlay overlay -olowerdir=/a\:lower\:\:dir /merged
-Since kernel version v6.5, directory names containing colons can also
-be provided as lower layer using the fsconfig syscall from new mount api:
+Since kernel version v6.8, directory names containing colons can also
+be configured as lower layer using the "lowerdir+" mount options and the
+fsconfig syscall from new mount api. For example:
- fsconfig(fs_fd, FSCONFIG_SET_STRING, "lowerdir", "/a:lower::dir", 0);
+ fsconfig(fs_fd, FSCONFIG_SET_STRING, "lowerdir+", "/a:lower::dir", 0);
In the latter case, colons in lower layer directory names will be escaped
as an octal characters (\072) when displayed in /proc/self/mountinfo.
when a "metacopy" file in one of the lower layers above it, has a "redirect"
to the absolute path of the "lower data" file in the "data-only" lower layer.
+Since kernel version v6.8, "data-only" lower layers can also be added using
+the "datadir+" mount options and the fsconfig syscall from new mount api.
+For example:
+
+ fsconfig(fs_fd, FSCONFIG_SET_STRING, "lowerdir+", "/l1", 0);
+ fsconfig(fs_fd, FSCONFIG_SET_STRING, "lowerdir+", "/l2", 0);
+ fsconfig(fs_fd, FSCONFIG_SET_STRING, "lowerdir+", "/l3", 0);
+ fsconfig(fs_fd, FSCONFIG_SET_STRING, "datadir+", "/do1", 0);
+ fsconfig(fs_fd, FSCONFIG_SET_STRING, "datadir+", "/do2", 0);
+
fs-verity support
----------------------
to a different machine. With the "inodes index" feature, trying to mount
the copied layers will fail the verification of the lower root file handle.
+Nesting overlayfs mounts
+------------------------
+
+It is possible to use a lower directory that is stored on an overlayfs
+mount. For regular files this does not need any special care. However, files
+that have overlayfs attributes, such as whiteouts or "overlay.*" xattrs will be
+interpreted by the underlying overlayfs mount and stripped out. In order to
+allow the second overlayfs mount to see the attributes they must be escaped.
+
+Overlayfs specific xattrs are escaped by using a special prefix of
+"overlay.overlay.". So, a file with a "trusted.overlay.overlay.metacopy" xattr
+in the lower dir will be exposed as a regular file with a
+"trusted.overlay.metacopy" xattr in the overlayfs mount. This can be nested by
+repeating the prefix multiple time, as each instance only removes one prefix.
+
+A lower dir with a regular whiteout will always be handled by the overlayfs
+mount, so to support storing an effective whiteout file in an overlayfs mount an
+alternative form of whiteout is supported. This form is a regular, zero-size
+file with the "overlay.whiteout" xattr set, inside a directory with the
+"overlay.whiteouts" xattr set. Such whiteouts are never created by overlayfs,
+but can be used by userspace tools (like containers) that generate lower layers.
+These alternative whiteouts can be escaped using the standard xattr escape
+mechanism in order to properly nest to any depth.
Non-standard behavior
---------------------
obj-$(CONFIG_OVERLAY_FS) += overlay.o
overlay-objs := super.o namei.o util.o inode.o file.o dir.o readdir.o \
- copy_up.o export.o params.o
+ copy_up.o export.o params.o xattrs.o
return PTR_ERR(old_file);
/* Try to use clone_file_range to clone up within the same fs */
+ ovl_start_write(dentry);
cloned = do_clone_file_range(old_file, 0, new_file, 0, len, 0);
+ ovl_end_write(dentry);
if (cloned == len)
goto out_fput;
/* Couldn't clone, so now we try to copy the data */
* it may not recognize all kind of holes and sometimes
* only skips partial of hole area. However, it will be
* enough for most of the use cases.
+ *
+ * We do not hold upper sb_writers throughout the loop to avert
+ * lockdep warning with llseek of lower file in nested overlay:
+ * - upper sb_writers
+ * -- lower ovl_inode_lock (ovl_llseek)
*/
-
if (skip_hole && data_pos < old_pos) {
data_pos = vfs_llseek(old_file, old_pos, SEEK_DATA);
if (data_pos > old_pos) {
}
}
+ ovl_start_write(dentry);
bytes = do_splice_direct(old_file, &old_pos,
new_file, &new_pos,
this_len, SPLICE_F_MOVE);
+ ovl_end_write(dentry);
if (bytes <= 0) {
error = bytes;
break;
return ERR_PTR(err);
}
-int ovl_set_origin(struct ovl_fs *ofs, struct dentry *lower,
- struct dentry *upper)
+struct ovl_fh *ovl_get_origin_fh(struct ovl_fs *ofs, struct dentry *origin)
{
- const struct ovl_fh *fh = NULL;
- int err;
-
/*
* When lower layer doesn't support export operations store a 'null' fh,
* so we can use the overlay.origin xattr to distignuish between a copy
* up and a pure upper inode.
*/
- if (ovl_can_decode_fh(lower->d_sb)) {
- fh = ovl_encode_real_fh(ofs, lower, false);
- if (IS_ERR(fh))
- return PTR_ERR(fh);
- }
+ if (!ovl_can_decode_fh(origin->d_sb))
+ return NULL;
+
+ return ovl_encode_real_fh(ofs, origin, false);
+}
+
+int ovl_set_origin_fh(struct ovl_fs *ofs, const struct ovl_fh *fh,
+ struct dentry *upper)
+{
+ int err;
/*
* Do not fail when upper doesn't support xattrs.
*/
err = ovl_check_setxattr(ofs, upper, OVL_XATTR_ORIGIN, fh->buf,
fh ? fh->fb.len : 0, 0);
- kfree(fh);
/* Ignore -EPERM from setting "user.*" on symlink/special */
return err == -EPERM ? 0 : err;
*
* Caller must hold i_mutex on indexdir.
*/
-static int ovl_create_index(struct dentry *dentry, struct dentry *origin,
+static int ovl_create_index(struct dentry *dentry, const struct ovl_fh *fh,
struct dentry *upper)
{
struct ovl_fs *ofs = OVL_FS(dentry->d_sb);
if (WARN_ON(ovl_test_flag(OVL_INDEX, d_inode(dentry))))
return -EIO;
- err = ovl_get_index_name(ofs, origin, &name);
+ err = ovl_get_index_name_fh(fh, &name);
if (err)
return err;
struct dentry *destdir;
struct qstr destname;
struct dentry *workdir;
+ const struct ovl_fh *origin_fh;
bool origin;
bool indexed;
bool metacopy;
struct ovl_fs *ofs = OVL_FS(c->dentry->d_sb);
struct inode *udir = d_inode(upperdir);
+ ovl_start_write(c->dentry);
+
/* Mark parent "impure" because it may now contain non-pure upper */
err = ovl_set_impure(c->parent, upperdir);
if (err)
- return err;
+ goto out;
err = ovl_set_nlink_lower(c->dentry);
if (err)
- return err;
+ goto out;
inode_lock_nested(udir, I_MUTEX_PARENT);
upper = ovl_lookup_upper(ofs, c->dentry->d_name.name, upperdir,
}
inode_unlock(udir);
if (err)
- return err;
+ goto out;
err = ovl_set_nlink_upper(c->dentry);
+out:
+ ovl_end_write(c->dentry);
return err;
}
* hard link.
*/
if (c->origin) {
- err = ovl_set_origin(ofs, c->lowerpath.dentry, temp);
+ err = ovl_set_origin_fh(ofs, c->origin_fh, temp);
if (err)
return err;
}
.link = c->link
};
- /* workdir and destdir could be the same when copying up to indexdir */
- err = -EIO;
- if (lock_rename(c->workdir, c->destdir) != NULL)
- goto unlock;
-
err = ovl_prep_cu_creds(c->dentry, &cc);
if (err)
- goto unlock;
+ return err;
+ ovl_start_write(c->dentry);
+ inode_lock(wdir);
temp = ovl_create_temp(ofs, c->workdir, &cattr);
+ inode_unlock(wdir);
+ ovl_end_write(c->dentry);
ovl_revert_cu_creds(&cc);
- err = PTR_ERR(temp);
if (IS_ERR(temp))
- goto unlock;
+ return PTR_ERR(temp);
/*
* Copy up data first and then xattrs. Writing data after
*/
path.dentry = temp;
err = ovl_copy_up_data(c, &path);
- if (err)
+ /*
+ * We cannot hold lock_rename() throughout this helper, because or
+ * lock ordering with sb_writers, which shouldn't be held when calling
+ * ovl_copy_up_data(), so lock workdir and destdir and make sure that
+ * temp wasn't moved before copy up completion or cleanup.
+ * If temp was moved, abort without the cleanup.
+ */
+ ovl_start_write(c->dentry);
+ if (lock_rename(c->workdir, c->destdir) != NULL ||
+ temp->d_parent != c->workdir) {
+ err = -EIO;
+ goto unlock;
+ } else if (err) {
goto cleanup;
+ }
err = ovl_copy_up_metadata(c, temp);
if (err)
goto cleanup;
if (S_ISDIR(c->stat.mode) && c->indexed) {
- err = ovl_create_index(c->dentry, c->lowerpath.dentry, temp);
+ err = ovl_create_index(c->dentry, c->origin_fh, temp);
if (err)
goto cleanup;
}
ovl_set_flag(OVL_WHITEOUTS, inode);
unlock:
unlock_rename(c->workdir, c->destdir);
+ ovl_end_write(c->dentry);
return err;
if (err)
return err;
+ ovl_start_write(c->dentry);
tmpfile = ovl_do_tmpfile(ofs, c->workdir, c->stat.mode);
+ ovl_end_write(c->dentry);
ovl_revert_cu_creds(&cc);
-
if (IS_ERR(tmpfile))
return PTR_ERR(tmpfile);
goto out_fput;
}
+ ovl_start_write(c->dentry);
+
err = ovl_copy_up_metadata(c, temp);
if (err)
- goto out_fput;
+ goto out;
inode_lock_nested(udir, I_MUTEX_PARENT);
inode_unlock(udir);
if (err)
- goto out_fput;
+ goto out;
if (c->metacopy_digest)
ovl_set_flag(OVL_HAS_DIGEST, d_inode(c->dentry));
ovl_set_upperdata(d_inode(c->dentry));
ovl_inode_update(d_inode(c->dentry), dget(temp));
+out:
+ ovl_end_write(c->dentry);
out_fput:
fput(tmpfile);
return err;
{
int err;
struct ovl_fs *ofs = OVL_FS(c->dentry->d_sb);
+ struct dentry *origin = c->lowerpath.dentry;
+ struct ovl_fh *fh = NULL;
bool to_index = false;
/*
to_index = true;
}
- if (S_ISDIR(c->stat.mode) || c->stat.nlink == 1 || to_index)
+ if (S_ISDIR(c->stat.mode) || c->stat.nlink == 1 || to_index) {
+ fh = ovl_get_origin_fh(ofs, origin);
+ if (IS_ERR(fh))
+ return PTR_ERR(fh);
+
+ /* origin_fh may be NULL */
+ c->origin_fh = fh;
c->origin = true;
+ }
if (to_index) {
c->destdir = ovl_indexdir(c->dentry->d_sb);
- err = ovl_get_index_name(ofs, c->lowerpath.dentry, &c->destname);
+ err = ovl_get_index_name(ofs, origin, &c->destname);
if (err)
- return err;
+ goto out_free_fh;
} else if (WARN_ON(!c->parent)) {
/* Disconnected dentry must be copied up to index dir */
- return -EIO;
+ err = -EIO;
+ goto out_free_fh;
} else {
/*
* Mark parent "impure" because it may now contain non-pure
* upper
*/
+ ovl_start_write(c->dentry);
err = ovl_set_impure(c->parent, c->destdir);
+ ovl_end_write(c->dentry);
if (err)
- return err;
+ goto out_free_fh;
}
/* Should we copyup with O_TMPFILE or with workdir? */
if (c->indexed)
ovl_set_flag(OVL_INDEX, d_inode(c->dentry));
+ ovl_start_write(c->dentry);
if (to_index) {
/* Initialize nlink for copy up of disconnected dentry */
err = ovl_set_nlink_upper(c->dentry);
ovl_dentry_set_upper_alias(c->dentry);
ovl_dentry_update_reval(c->dentry, ovl_dentry_upper(c->dentry));
}
+ ovl_end_write(c->dentry);
out:
if (to_index)
kfree(c->destname.name);
+out_free_fh:
+ kfree(fh);
return err;
}
* Writing to upper file will clear security.capability xattr. We
* don't want that to happen for normal copy-up operation.
*/
+ ovl_start_write(c->dentry);
if (capability) {
err = ovl_do_setxattr(ofs, upperpath.dentry, XATTR_NAME_CAPS,
capability, cap_size, 0);
- if (err)
- goto out_free;
}
-
-
- err = ovl_removexattr(ofs, upperpath.dentry, OVL_XATTR_METACOPY);
+ if (!err) {
+ err = ovl_removexattr(ofs, upperpath.dentry,
+ OVL_XATTR_METACOPY);
+ }
+ ovl_end_write(c->dentry);
if (err)
goto out_free;
int ovl_maybe_copy_up(struct dentry *dentry, int flags)
{
- int err = 0;
-
- if (ovl_open_need_copy_up(dentry, flags)) {
- err = ovl_want_write(dentry);
- if (!err) {
- err = ovl_copy_up_flags(dentry, flags);
- ovl_drop_write(dentry);
- }
- }
+ if (!ovl_open_need_copy_up(dentry, flags))
+ return 0;
- return err;
+ return ovl_copy_up_flags(dentry, flags);
}
int ovl_copy_up_with_data(struct dentry *dentry)
goto out_unlock;
err = -ESTALE;
- if (d_is_negative(upper) || !IS_WHITEOUT(d_inode(upper)))
+ if (d_is_negative(upper) || !ovl_upper_is_whiteout(ofs, upper))
goto out_dput;
newdentry = ovl_create_temp(ofs, workdir, cattr);
struct cred *override_cred;
struct dentry *parent = dentry->d_parent;
- err = ovl_copy_up(parent);
- if (err)
- return err;
-
old_cred = ovl_override_creds(dentry->d_sb);
/*
.link = link,
};
+ err = ovl_copy_up(dentry->d_parent);
+ if (err)
+ return err;
+
err = ovl_want_write(dentry);
if (err)
goto out;
int err;
struct inode *inode;
- err = ovl_want_write(old);
+ err = ovl_copy_up(old);
if (err)
goto out;
- err = ovl_copy_up(old);
+ err = ovl_copy_up(new->d_parent);
if (err)
- goto out_drop_write;
+ goto out;
- err = ovl_copy_up(new->d_parent);
+ err = ovl_nlink_start(old);
if (err)
- goto out_drop_write;
+ goto out;
if (ovl_is_metacopy_dentry(old)) {
err = ovl_set_link_redirect(old);
if (err)
- goto out_drop_write;
+ goto out_nlink_end;
}
- err = ovl_nlink_start(old);
- if (err)
- goto out_drop_write;
-
inode = d_inode(old);
ihold(inode);
if (err)
iput(inode);
+out_nlink_end:
ovl_nlink_end(old);
-out_drop_write:
- ovl_drop_write(old);
out:
return err;
}
goto out;
}
- err = ovl_want_write(dentry);
- if (err)
- goto out;
-
err = ovl_copy_up(dentry->d_parent);
if (err)
- goto out_drop_write;
+ goto out;
err = ovl_nlink_start(dentry);
if (err)
- goto out_drop_write;
+ goto out;
old_cred = ovl_override_creds(dentry->d_sb);
if (!lower_positive)
if (ovl_dentry_upper(dentry))
ovl_copyattr(d_inode(dentry));
-out_drop_write:
- ovl_drop_write(dentry);
out:
ovl_cache_free(&list);
return err;
}
}
- err = ovl_want_write(old);
- if (err)
- goto out;
-
err = ovl_copy_up(old);
if (err)
- goto out_drop_write;
+ goto out;
err = ovl_copy_up(new->d_parent);
if (err)
- goto out_drop_write;
+ goto out;
if (!overwrite) {
err = ovl_copy_up(new);
if (err)
- goto out_drop_write;
+ goto out;
} else if (d_inode(new)) {
err = ovl_nlink_start(new);
if (err)
- goto out_drop_write;
+ goto out;
update_nlink = true;
}
+ if (!update_nlink) {
+ /* ovl_nlink_start() took ovl_want_write() */
+ err = ovl_want_write(old);
+ if (err)
+ goto out;
+ }
+
old_cred = ovl_override_creds(old->d_sb);
if (!list_empty(&list)) {
}
} else {
if (!d_is_negative(newdentry)) {
- if (!new_opaque || !ovl_is_whiteout(newdentry))
+ if (!new_opaque || !ovl_upper_is_whiteout(ofs, newdentry))
goto out_dput;
} else {
if (flags & RENAME_EXCHANGE)
revert_creds(old_cred);
if (update_nlink)
ovl_nlink_end(new);
-out_drop_write:
- ovl_drop_write(old);
+ else
+ ovl_drop_write(old);
out:
dput(opaquedir);
ovl_cache_free(&list);
if (ovl_dentry_upper(dentry))
return 0;
- err = ovl_want_write(dentry);
- if (!err) {
- err = ovl_copy_up(dentry);
- ovl_drop_write(dentry);
- }
-
+ err = ovl_copy_up(dentry);
if (err) {
pr_warn_ratelimited("failed to copy up on encode (%pd2, err=%i)\n",
dentry, err);
#include <linux/fs.h>
#include "overlayfs.h"
+#include "../internal.h" /* for sb_init_dio_done_wq */
+
struct ovl_aio_req {
struct kiocb iocb;
refcount_t ref;
struct kiocb *orig_iocb;
+ /* used for aio completion */
+ struct work_struct work;
+ long res;
};
static struct kmem_cache *ovl_aio_request_cachep;
return ret;
}
+static void ovl_file_modified(struct file *file)
+{
+ /* Update size/mtime */
+ ovl_copyattr(file_inode(file));
+}
+
static void ovl_file_accessed(struct file *file)
{
struct inode *inode, *upperinode;
touch_atime(&file->f_path);
}
-static rwf_t ovl_iocb_to_rwf(int ifl)
+#define OVL_IOCB_MASK \
+ (IOCB_NOWAIT | IOCB_HIPRI | IOCB_DSYNC | IOCB_SYNC | IOCB_APPEND)
+
+static rwf_t iocb_to_rw_flags(int flags)
{
- rwf_t flags = 0;
-
- if (ifl & IOCB_NOWAIT)
- flags |= RWF_NOWAIT;
- if (ifl & IOCB_HIPRI)
- flags |= RWF_HIPRI;
- if (ifl & IOCB_DSYNC)
- flags |= RWF_DSYNC;
- if (ifl & IOCB_SYNC)
- flags |= RWF_SYNC;
-
- return flags;
+ return (__force rwf_t)(flags & OVL_IOCB_MASK);
}
static inline void ovl_aio_put(struct ovl_aio_req *aio_req)
struct kiocb *orig_iocb = aio_req->orig_iocb;
if (iocb->ki_flags & IOCB_WRITE) {
- struct inode *inode = file_inode(orig_iocb->ki_filp);
-
kiocb_end_write(iocb);
- ovl_copyattr(inode);
+ ovl_file_modified(orig_iocb->ki_filp);
}
orig_iocb->ki_pos = iocb->ki_pos;
orig_iocb->ki_complete(orig_iocb, res);
}
+static void ovl_aio_complete_work(struct work_struct *work)
+{
+ struct ovl_aio_req *aio_req = container_of(work,
+ struct ovl_aio_req, work);
+
+ ovl_aio_rw_complete(&aio_req->iocb, aio_req->res);
+}
+
+static void ovl_aio_queue_completion(struct kiocb *iocb, long res)
+{
+ struct ovl_aio_req *aio_req = container_of(iocb,
+ struct ovl_aio_req, iocb);
+ struct kiocb *orig_iocb = aio_req->orig_iocb;
+
+ /*
+ * Punt to a work queue to serialize updates of mtime/size.
+ */
+ aio_req->res = res;
+ INIT_WORK(&aio_req->work, ovl_aio_complete_work);
+ queue_work(file_inode(orig_iocb->ki_filp)->i_sb->s_dio_done_wq,
+ &aio_req->work);
+}
+
+static int ovl_init_aio_done_wq(struct super_block *sb)
+{
+ if (sb->s_dio_done_wq)
+ return 0;
+
+ return sb_init_dio_done_wq(sb);
+}
+
static ssize_t ovl_read_iter(struct kiocb *iocb, struct iov_iter *iter)
{
struct file *file = iocb->ki_filp;
old_cred = ovl_override_creds(file_inode(file)->i_sb);
if (is_sync_kiocb(iocb)) {
- ret = vfs_iter_read(real.file, iter, &iocb->ki_pos,
- ovl_iocb_to_rwf(iocb->ki_flags));
+ rwf_t rwf = iocb_to_rw_flags(iocb->ki_flags);
+
+ ret = vfs_iter_read(real.file, iter, &iocb->ki_pos, rwf);
} else {
struct ovl_aio_req *aio_req;
old_cred = ovl_override_creds(file_inode(file)->i_sb);
if (is_sync_kiocb(iocb)) {
+ rwf_t rwf = iocb_to_rw_flags(ifl);
+
file_start_write(real.file);
- ret = vfs_iter_write(real.file, iter, &iocb->ki_pos,
- ovl_iocb_to_rwf(ifl));
+ ret = vfs_iter_write(real.file, iter, &iocb->ki_pos, rwf);
file_end_write(real.file);
/* Update size */
- ovl_copyattr(inode);
+ ovl_file_modified(file);
} else {
struct ovl_aio_req *aio_req;
+ ret = ovl_init_aio_done_wq(inode->i_sb);
+ if (ret)
+ goto out;
+
ret = -ENOMEM;
aio_req = kmem_cache_zalloc(ovl_aio_request_cachep, GFP_KERNEL);
if (!aio_req)
aio_req->orig_iocb = iocb;
kiocb_clone(&aio_req->iocb, iocb, get_file(real.file));
aio_req->iocb.ki_flags = ifl;
- aio_req->iocb.ki_complete = ovl_aio_rw_complete;
+ aio_req->iocb.ki_complete = ovl_aio_queue_completion;
refcount_set(&aio_req->ref, 2);
kiocb_start_write(&aio_req->iocb);
ret = vfs_iocb_iter_write(real.file, &aio_req->iocb, iter);
file_end_write(real.file);
/* Update size */
- ovl_copyattr(inode);
+ ovl_file_modified(out);
revert_creds(old_cred);
fdput(real);
revert_creds(old_cred);
/* Update size */
- ovl_copyattr(inode);
+ ovl_file_modified(file);
fdput(real);
revert_creds(old_cred);
/* Update size */
- ovl_copyattr(inode_out);
+ ovl_file_modified(file_out);
fdput(real_in);
fdput(real_out);
if (err)
return err;
- err = ovl_want_write(dentry);
- if (err)
- goto out;
-
if (attr->ia_valid & ATTR_SIZE) {
/* Truncate should trigger data copy up as well */
full_copy_up = true;
winode = d_inode(upperdentry);
err = get_write_access(winode);
if (err)
- goto out_drop_write;
+ goto out;
}
if (attr->ia_valid & (ATTR_KILL_SUID|ATTR_KILL_SGID))
*/
attr->ia_valid &= ~ATTR_OPEN;
+ err = ovl_want_write(dentry);
+ if (err)
+ goto out_put_write;
+
inode_lock(upperdentry->d_inode);
old_cred = ovl_override_creds(dentry->d_sb);
err = ovl_do_notify_change(ofs, upperdentry, attr);
if (!err)
ovl_copyattr(dentry->d_inode);
inode_unlock(upperdentry->d_inode);
+ ovl_drop_write(dentry);
+out_put_write:
if (winode)
put_write_access(winode);
}
-out_drop_write:
- ovl_drop_write(dentry);
out:
return err;
}
return p;
}
-bool ovl_is_private_xattr(struct super_block *sb, const char *name)
-{
- struct ovl_fs *ofs = OVL_FS(sb);
-
- if (ofs->config.userxattr)
- return strncmp(name, OVL_XATTR_USER_PREFIX,
- sizeof(OVL_XATTR_USER_PREFIX) - 1) == 0;
- else
- return strncmp(name, OVL_XATTR_TRUSTED_PREFIX,
- sizeof(OVL_XATTR_TRUSTED_PREFIX) - 1) == 0;
-}
-
-int ovl_xattr_set(struct dentry *dentry, struct inode *inode, const char *name,
- const void *value, size_t size, int flags)
-{
- int err;
- struct ovl_fs *ofs = OVL_FS(dentry->d_sb);
- struct dentry *upperdentry = ovl_i_dentry_upper(inode);
- struct dentry *realdentry = upperdentry ?: ovl_dentry_lower(dentry);
- struct path realpath;
- const struct cred *old_cred;
-
- err = ovl_want_write(dentry);
- if (err)
- goto out;
-
- if (!value && !upperdentry) {
- ovl_path_lower(dentry, &realpath);
- old_cred = ovl_override_creds(dentry->d_sb);
- err = vfs_getxattr(mnt_idmap(realpath.mnt), realdentry, name, NULL, 0);
- revert_creds(old_cred);
- if (err < 0)
- goto out_drop_write;
- }
-
- if (!upperdentry) {
- err = ovl_copy_up(dentry);
- if (err)
- goto out_drop_write;
-
- realdentry = ovl_dentry_upper(dentry);
- }
-
- old_cred = ovl_override_creds(dentry->d_sb);
- if (value) {
- err = ovl_do_setxattr(ofs, realdentry, name, value, size,
- flags);
- } else {
- WARN_ON(flags != XATTR_REPLACE);
- err = ovl_do_removexattr(ofs, realdentry, name);
- }
- revert_creds(old_cred);
-
- /* copy c/mtime */
- ovl_copyattr(inode);
-
-out_drop_write:
- ovl_drop_write(dentry);
-out:
- return err;
-}
-
-int ovl_xattr_get(struct dentry *dentry, struct inode *inode, const char *name,
- void *value, size_t size)
-{
- ssize_t res;
- const struct cred *old_cred;
- struct path realpath;
-
- ovl_i_path_real(inode, &realpath);
- old_cred = ovl_override_creds(dentry->d_sb);
- res = vfs_getxattr(mnt_idmap(realpath.mnt), realpath.dentry, name, value, size);
- revert_creds(old_cred);
- return res;
-}
-
-static bool ovl_can_list(struct super_block *sb, const char *s)
-{
- /* Never list private (.overlay) */
- if (ovl_is_private_xattr(sb, s))
- return false;
-
- /* List all non-trusted xattrs */
- if (strncmp(s, XATTR_TRUSTED_PREFIX, XATTR_TRUSTED_PREFIX_LEN) != 0)
- return true;
-
- /* list other trusted for superuser only */
- return ns_capable_noaudit(&init_user_ns, CAP_SYS_ADMIN);
-}
-
-ssize_t ovl_listxattr(struct dentry *dentry, char *list, size_t size)
-{
- struct dentry *realdentry = ovl_dentry_real(dentry);
- ssize_t res;
- size_t len;
- char *s;
- const struct cred *old_cred;
-
- old_cred = ovl_override_creds(dentry->d_sb);
- res = vfs_listxattr(realdentry, list, size);
- revert_creds(old_cred);
- if (res <= 0 || size == 0)
- return res;
-
- /* filter out private xattrs */
- for (s = list, len = res; len;) {
- size_t slen = strnlen(s, len) + 1;
-
- /* underlying fs providing us with an broken xattr list? */
- if (WARN_ON(slen > len))
- return -EIO;
-
- len -= slen;
- if (!ovl_can_list(dentry->d_sb, s)) {
- res -= slen;
- memmove(s, s + slen, len);
- } else {
- s += slen;
- }
- }
-
- return res;
-}
-
#ifdef CONFIG_FS_POSIX_ACL
/*
* Apply the idmapping of the layer to POSIX ACLs. The caller must pass a clone
struct dentry *upperdentry = ovl_dentry_upper(dentry);
struct dentry *realdentry = upperdentry ?: ovl_dentry_lower(dentry);
- err = ovl_want_write(dentry);
- if (err)
- return err;
-
/*
* If ACL is to be removed from a lower file, check if it exists in
* the first place before copying it up.
revert_creds(old_cred);
if (IS_ERR(real_acl)) {
err = PTR_ERR(real_acl);
- goto out_drop_write;
+ goto out;
}
posix_acl_release(real_acl);
}
if (!upperdentry) {
err = ovl_copy_up(dentry);
if (err)
- goto out_drop_write;
+ goto out;
realdentry = ovl_dentry_upper(dentry);
}
+ err = ovl_want_write(dentry);
+ if (err)
+ goto out;
+
old_cred = ovl_override_creds(dentry->d_sb);
if (acl)
err = ovl_do_set_acl(ofs, realdentry, acl_name, acl);
else
err = ovl_do_remove_acl(ofs, realdentry, acl_name);
revert_creds(old_cred);
+ ovl_drop_write(dentry);
/* copy c/mtime */
ovl_copyattr(inode);
-
-out_drop_write:
- ovl_drop_write(dentry);
+out:
return err;
}
unsigned int flags;
int err;
- err = ovl_want_write(dentry);
- if (err)
- goto out;
-
err = ovl_copy_up(dentry);
if (!err) {
ovl_path_real(dentry, &upperpath);
+ err = ovl_want_write(dentry);
+ if (err)
+ goto out;
+
old_cred = ovl_override_creds(inode->i_sb);
/*
* Store immutable/append-only flags in xattr and clear them
if (!err)
err = ovl_real_fileattr_set(&upperpath, fa);
revert_creds(old_cred);
+ ovl_drop_write(dentry);
/*
* Merge real inode flags with inode flags read from
/* Update ctime */
ovl_copyattr(inode);
}
- ovl_drop_write(dentry);
out:
return err;
}
err = -EREMOTE;
goto out_err;
}
- if (ovl_is_whiteout(this)) {
+
+ path.dentry = this;
+ path.mnt = d->mnt;
+ if (ovl_path_is_whiteout(OVL_FS(d->sb), &path)) {
d->stop = d->opaque = true;
goto put_and_out;
}
goto put_and_out;
}
- path.dentry = this;
- path.mnt = d->mnt;
if (!d_can_lookup(this)) {
if (d->is_dir || !last_element) {
d->stop = true;
else if (IS_ERR(origin))
return PTR_ERR(origin);
- if (upperdentry && !ovl_is_whiteout(upperdentry) &&
+ if (upperdentry && !ovl_upper_is_whiteout(ofs, upperdentry) &&
inode_wrong_type(d_inode(upperdentry), d_inode(origin)->i_mode))
goto invalid;
return err;
}
+int ovl_verify_set_fh(struct ovl_fs *ofs, struct dentry *dentry,
+ enum ovl_xattr ox, const struct ovl_fh *fh,
+ bool is_upper, bool set)
+{
+ int err;
+
+ err = ovl_verify_fh(ofs, dentry, ox, fh);
+ if (set && err == -ENODATA)
+ err = ovl_setxattr(ofs, dentry, ox, fh->buf, fh->fb.len);
+
+ return err;
+}
+
/*
* Verify that @real dentry matches the file handle stored in xattr @name.
*
*
* Return 0 on match, -ESTALE on mismatch, -ENODATA on no xattr, < 0 on error.
*/
-int ovl_verify_set_fh(struct ovl_fs *ofs, struct dentry *dentry,
- enum ovl_xattr ox, struct dentry *real, bool is_upper,
- bool set)
+int ovl_verify_origin_xattr(struct ovl_fs *ofs, struct dentry *dentry,
+ enum ovl_xattr ox, struct dentry *real,
+ bool is_upper, bool set)
{
struct inode *inode;
struct ovl_fh *fh;
goto fail;
}
- err = ovl_verify_fh(ofs, dentry, ox, fh);
- if (set && err == -ENODATA)
- err = ovl_setxattr(ofs, dentry, ox, fh->buf, fh->fb.len);
+ err = ovl_verify_set_fh(ofs, dentry, ox, fh, is_upper, set);
if (err)
goto fail;
goto out;
}
+
/* Get upper dentry from index */
struct dentry *ovl_index_upper(struct ovl_fs *ofs, struct dentry *index,
bool connected)
goto out;
}
-static int ovl_get_index_name_fh(struct ovl_fh *fh, struct qstr *name)
+int ovl_get_index_name_fh(const struct ovl_fh *fh, struct qstr *name)
{
char *n, *s;
static int ovl_fix_origin(struct ovl_fs *ofs, struct dentry *dentry,
struct dentry *lower, struct dentry *upper)
{
+ const struct ovl_fh *fh;
int err;
if (ovl_check_origin_xattr(ofs, upper))
return 0;
+ fh = ovl_get_origin_fh(ofs, lower);
+ if (IS_ERR(fh))
+ return PTR_ERR(fh);
+
err = ovl_want_write(dentry);
if (err)
- return err;
+ goto out;
- err = ovl_set_origin(ofs, lower, upper);
+ err = ovl_set_origin_fh(ofs, fh, upper);
if (!err)
err = ovl_set_impure(dentry->d_parent, upper->d_parent);
ovl_drop_write(dentry);
+out:
+ kfree(fh);
return err;
}
break;
}
} else {
- positive = !ovl_is_whiteout(this);
+ struct path path = {
+ .dentry = this,
+ .mnt = parentpath->layer->mnt,
+ };
+ positive = !ovl_path_is_whiteout(OVL_FS(dentry->d_sb), &path);
done = true;
dput(this);
}
#define OVL_XATTR_NAMESPACE "overlay."
#define OVL_XATTR_TRUSTED_PREFIX XATTR_TRUSTED_PREFIX OVL_XATTR_NAMESPACE
+#define OVL_XATTR_TRUSTED_PREFIX_LEN (sizeof(OVL_XATTR_TRUSTED_PREFIX) - 1)
#define OVL_XATTR_USER_PREFIX XATTR_USER_PREFIX OVL_XATTR_NAMESPACE
+#define OVL_XATTR_USER_PREFIX_LEN (sizeof(OVL_XATTR_USER_PREFIX) - 1)
+
+#define OVL_XATTR_ESCAPE_PREFIX OVL_XATTR_NAMESPACE
+#define OVL_XATTR_ESCAPE_PREFIX_LEN (sizeof(OVL_XATTR_ESCAPE_PREFIX) - 1)
+#define OVL_XATTR_ESCAPE_TRUSTED_PREFIX OVL_XATTR_TRUSTED_PREFIX OVL_XATTR_ESCAPE_PREFIX
+#define OVL_XATTR_ESCAPE_TRUSTED_PREFIX_LEN (sizeof(OVL_XATTR_ESCAPE_TRUSTED_PREFIX) - 1)
+#define OVL_XATTR_ESCAPE_USER_PREFIX OVL_XATTR_USER_PREFIX OVL_XATTR_ESCAPE_PREFIX
+#define OVL_XATTR_ESCAPE_USER_PREFIX_LEN (sizeof(OVL_XATTR_ESCAPE_USER_PREFIX) - 1)
enum ovl_xattr {
OVL_XATTR_OPAQUE,
OVL_XATTR_UUID,
OVL_XATTR_METACOPY,
OVL_XATTR_PROTATTR,
+ OVL_XATTR_XWHITEOUT,
+ OVL_XATTR_XWHITEOUTS,
};
enum ovl_inode_flag {
}
/* util.c */
+int ovl_get_write_access(struct dentry *dentry);
+void ovl_put_write_access(struct dentry *dentry);
+void ovl_start_write(struct dentry *dentry);
+void ovl_end_write(struct dentry *dentry);
int ovl_want_write(struct dentry *dentry);
void ovl_drop_write(struct dentry *dentry);
struct dentry *ovl_workdir(struct dentry *dentry);
void ovl_dir_modified(struct dentry *dentry, bool impurity);
u64 ovl_inode_version_get(struct inode *inode);
bool ovl_is_whiteout(struct dentry *dentry);
+bool ovl_path_is_whiteout(struct ovl_fs *ofs, const struct path *path);
struct file *ovl_path_open(const struct path *path, int flags);
int ovl_copy_up_start(struct dentry *dentry, int flags);
void ovl_copy_up_end(struct dentry *dentry);
bool ovl_path_check_dir_xattr(struct ovl_fs *ofs, const struct path *path,
enum ovl_xattr ox);
bool ovl_path_check_origin_xattr(struct ovl_fs *ofs, const struct path *path);
+bool ovl_path_check_xwhiteout_xattr(struct ovl_fs *ofs, const struct path *path);
+bool ovl_path_check_xwhiteouts_xattr(struct ovl_fs *ofs, const struct path *path);
bool ovl_init_uuid_xattr(struct super_block *sb, struct ovl_fs *ofs,
const struct path *upperpath);
+static inline bool ovl_upper_is_whiteout(struct ovl_fs *ofs,
+ struct dentry *upperdentry)
+{
+ struct path upperpath = {
+ .dentry = upperdentry,
+ .mnt = ovl_upper_mnt(ofs),
+ };
+ return ovl_path_is_whiteout(ofs, &upperpath);
+}
+
static inline bool ovl_check_origin_xattr(struct ovl_fs *ofs,
struct dentry *upperdentry)
{
int ovl_check_origin_fh(struct ovl_fs *ofs, struct ovl_fh *fh, bool connected,
struct dentry *upperdentry, struct ovl_path **stackp);
int ovl_verify_set_fh(struct ovl_fs *ofs, struct dentry *dentry,
- enum ovl_xattr ox, struct dentry *real, bool is_upper,
- bool set);
+ enum ovl_xattr ox, const struct ovl_fh *fh,
+ bool is_upper, bool set);
+int ovl_verify_origin_xattr(struct ovl_fs *ofs, struct dentry *dentry,
+ enum ovl_xattr ox, struct dentry *real,
+ bool is_upper, bool set);
struct dentry *ovl_index_upper(struct ovl_fs *ofs, struct dentry *index,
bool connected);
int ovl_verify_index(struct ovl_fs *ofs, struct dentry *index);
+int ovl_get_index_name_fh(const struct ovl_fh *fh, struct qstr *name);
int ovl_get_index_name(struct ovl_fs *ofs, struct dentry *origin,
struct qstr *name);
struct dentry *ovl_get_index_fh(struct ovl_fs *ofs, struct ovl_fh *fh);
unsigned int flags);
bool ovl_lower_positive(struct dentry *dentry);
+static inline int ovl_verify_origin_fh(struct ovl_fs *ofs, struct dentry *upper,
+ const struct ovl_fh *fh, bool set)
+{
+ return ovl_verify_set_fh(ofs, upper, OVL_XATTR_ORIGIN, fh, false, set);
+}
+
static inline int ovl_verify_origin(struct ovl_fs *ofs, struct dentry *upper,
struct dentry *origin, bool set)
{
- return ovl_verify_set_fh(ofs, upper, OVL_XATTR_ORIGIN, origin,
- false, set);
+ return ovl_verify_origin_xattr(ofs, upper, OVL_XATTR_ORIGIN, origin,
+ false, set);
}
static inline int ovl_verify_upper(struct ovl_fs *ofs, struct dentry *index,
struct dentry *upper, bool set)
{
- return ovl_verify_set_fh(ofs, index, OVL_XATTR_UPPER, upper, true, set);
+ return ovl_verify_origin_xattr(ofs, index, OVL_XATTR_UPPER, upper,
+ true, set);
}
/* readdir.c */
unsigned int ovl_get_nlink(struct ovl_fs *ofs, struct dentry *lowerdentry,
struct dentry *upperdentry,
unsigned int fallback);
-int ovl_setattr(struct mnt_idmap *idmap, struct dentry *dentry,
- struct iattr *attr);
-int ovl_getattr(struct mnt_idmap *idmap, const struct path *path,
- struct kstat *stat, u32 request_mask, unsigned int flags);
int ovl_permission(struct mnt_idmap *idmap, struct inode *inode,
int mask);
-int ovl_xattr_set(struct dentry *dentry, struct inode *inode, const char *name,
- const void *value, size_t size, int flags);
-int ovl_xattr_get(struct dentry *dentry, struct inode *inode, const char *name,
- void *value, size_t size);
-ssize_t ovl_listxattr(struct dentry *dentry, char *list, size_t size);
#ifdef CONFIG_FS_POSIX_ACL
struct posix_acl *do_ovl_get_acl(struct mnt_idmap *idmap,
int ovl_set_attr(struct ovl_fs *ofs, struct dentry *upper, struct kstat *stat);
struct ovl_fh *ovl_encode_real_fh(struct ovl_fs *ofs, struct dentry *real,
bool is_upper);
-int ovl_set_origin(struct ovl_fs *ofs, struct dentry *lower,
- struct dentry *upper);
+struct ovl_fh *ovl_get_origin_fh(struct ovl_fs *ofs, struct dentry *origin);
+int ovl_set_origin_fh(struct ovl_fs *ofs, const struct ovl_fh *fh,
+ struct dentry *upper);
/* export.c */
extern const struct export_operations ovl_export_operations;
{
return (!ovl_upper_mnt(ofs) || !ofs->workdir);
}
+
+/* xattr.c */
+
+const struct xattr_handler * const *ovl_xattr_handlers(struct ovl_fs *ofs);
+int ovl_setattr(struct mnt_idmap *idmap, struct dentry *dentry,
+ struct iattr *attr);
+int ovl_getattr(struct mnt_idmap *idmap, const struct path *path,
+ struct kstat *stat, u32 request_mask, unsigned int flags);
+ssize_t ovl_listxattr(struct dentry *dentry, char *list, size_t size);
MODULE_PARM_DESC(metacopy,
"Default to on or off for the metadata only copy up feature");
-enum {
+enum ovl_opt {
Opt_lowerdir,
+ Opt_lowerdir_add,
+ Opt_datadir_add,
Opt_upperdir,
Opt_workdir,
Opt_default_permissions,
#define fsparam_string_empty(NAME, OPT) \
__fsparam(fs_param_is_string, NAME, OPT, fs_param_can_be_empty, NULL)
+
const struct fs_parameter_spec ovl_parameter_spec[] = {
fsparam_string_empty("lowerdir", Opt_lowerdir),
+ fsparam_string("lowerdir+", Opt_lowerdir_add),
+ fsparam_string("datadir+", Opt_datadir_add),
fsparam_string("upperdir", Opt_upperdir),
fsparam_string("workdir", Opt_workdir),
fsparam_flag("default_permissions", Opt_default_permissions),
pr_err("failed to resolve '%s': %i\n", name, err);
goto out;
}
- err = -EINVAL;
- if (ovl_dentry_weird(path->dentry)) {
- pr_err("filesystem on '%s' not supported\n", name);
- goto out_put;
- }
- if (!d_is_dir(path->dentry)) {
- pr_err("'%s' not a directory\n", name);
- goto out_put;
- }
return 0;
-out_put:
- path_put_init(path);
out:
return err;
}
}
}
-static int ovl_mount_dir(const char *name, struct path *path, bool upper)
+static int ovl_mount_dir(const char *name, struct path *path)
{
int err = -ENOMEM;
char *tmp = kstrdup(name, GFP_KERNEL);
if (tmp) {
ovl_unescape(tmp);
err = ovl_mount_dir_noesc(tmp, path);
-
- if (!err && upper && path->dentry->d_flags & DCACHE_OP_REAL) {
- pr_err("filesystem on '%s' not supported as upperdir\n",
- tmp);
- path_put_init(path);
- err = -EINVAL;
- }
kfree(tmp);
}
return err;
}
-static int ovl_parse_param_upperdir(const char *name, struct fs_context *fc,
- bool workdir)
+static int ovl_mount_dir_check(struct fs_context *fc, const struct path *path,
+ enum ovl_opt layer, const char *name, bool upper)
{
- int err;
- struct ovl_fs *ofs = fc->s_fs_info;
- struct ovl_config *config = &ofs->config;
struct ovl_fs_context *ctx = fc->fs_private;
- struct path path;
- char *dup;
- err = ovl_mount_dir(name, &path, true);
- if (err)
- return err;
+ if (ovl_dentry_weird(path->dentry))
+ return invalfc(fc, "filesystem on %s not supported", name);
+
+ if (!d_is_dir(path->dentry))
+ return invalfc(fc, "%s is not a directory", name);
+
/*
* Check whether upper path is read-only here to report failures
* early. Don't forget to recheck when the superblock is created
* as the mount attributes could change.
*/
- if (__mnt_is_readonly(path.mnt)) {
- path_put(&path);
- return -EINVAL;
+ if (upper) {
+ if (path->dentry->d_flags & DCACHE_OP_REAL)
+ return invalfc(fc, "filesystem on %s not supported as upperdir", name);
+ if (__mnt_is_readonly(path->mnt))
+ return invalfc(fc, "filesystem on %s is read-only", name);
+ } else {
+ if (ctx->lowerdir_all && layer != Opt_lowerdir)
+ return invalfc(fc, "lowerdir+ and datadir+ cannot follow lowerdir");
+ if (ctx->nr_data && layer == Opt_lowerdir_add)
+ return invalfc(fc, "regular lower layers cannot follow data layers");
+ if (ctx->nr == OVL_MAX_STACK)
+ return invalfc(fc, "too many lower directories, limit is %d",
+ OVL_MAX_STACK);
}
+ return 0;
+}
- dup = kstrdup(name, GFP_KERNEL);
- if (!dup) {
- path_put(&path);
+static int ovl_ctx_realloc_lower(struct fs_context *fc)
+{
+ struct ovl_fs_context *ctx = fc->fs_private;
+ struct ovl_fs_context_layer *l;
+ size_t nr;
+
+ if (ctx->nr < ctx->capacity)
+ return 0;
+
+ nr = min_t(size_t, max(4096 / sizeof(*l), ctx->capacity * 2),
+ OVL_MAX_STACK);
+ l = krealloc_array(ctx->lower, nr, sizeof(*l), GFP_KERNEL_ACCOUNT);
+ if (!l)
return -ENOMEM;
+
+ ctx->lower = l;
+ ctx->capacity = nr;
+ return 0;
+}
+
+static void ovl_add_layer(struct fs_context *fc, enum ovl_opt layer,
+ struct path *path, char **pname)
+{
+ struct ovl_fs *ofs = fc->s_fs_info;
+ struct ovl_config *config = &ofs->config;
+ struct ovl_fs_context *ctx = fc->fs_private;
+ struct ovl_fs_context_layer *l;
+
+ switch (layer) {
+ case Opt_workdir:
+ swap(config->workdir, *pname);
+ swap(ctx->work, *path);
+ break;
+ case Opt_upperdir:
+ swap(config->upperdir, *pname);
+ swap(ctx->upper, *path);
+ break;
+ case Opt_datadir_add:
+ ctx->nr_data++;
+ fallthrough;
+ case Opt_lowerdir_add:
+ WARN_ON(ctx->nr >= ctx->capacity);
+ l = &ctx->lower[ctx->nr++];
+ memset(l, 0, sizeof(*l));
+ swap(l->name, *pname);
+ swap(l->path, *path);
+ break;
+ default:
+ WARN_ON(1);
}
+}
- if (workdir) {
- kfree(config->workdir);
- config->workdir = dup;
- path_put(&ctx->work);
- ctx->work = path;
- } else {
- kfree(config->upperdir);
- config->upperdir = dup;
- path_put(&ctx->upper);
- ctx->upper = path;
+static int ovl_parse_layer(struct fs_context *fc, struct fs_parameter *param,
+ enum ovl_opt layer)
+{
+ char *name = kstrdup(param->string, GFP_KERNEL);
+ bool upper = (layer == Opt_upperdir || layer == Opt_workdir);
+ struct path path;
+ int err;
+
+ if (!name)
+ return -ENOMEM;
+
+ if (upper)
+ err = ovl_mount_dir(name, &path);
+ else
+ err = ovl_mount_dir_noesc(name, &path);
+ if (err)
+ goto out_free;
+
+ err = ovl_mount_dir_check(fc, &path, layer, name, upper);
+ if (err)
+ goto out_put;
+
+ if (!upper) {
+ err = ovl_ctx_realloc_lower(fc);
+ if (err)
+ goto out_put;
}
- return 0;
+
+ /* Store the user provided path string in ctx to show in mountinfo */
+ ovl_add_layer(fc, layer, &path, &name);
+
+out_put:
+ path_put(&path);
+out_free:
+ kfree(name);
+ return err;
}
-static void ovl_parse_param_drop_lowerdir(struct ovl_fs_context *ctx)
+static void ovl_reset_lowerdirs(struct ovl_fs_context *ctx)
{
- for (size_t nr = 0; nr < ctx->nr; nr++) {
- path_put(&ctx->lower[nr].path);
- kfree(ctx->lower[nr].name);
- ctx->lower[nr].name = NULL;
+ struct ovl_fs_context_layer *l = ctx->lower;
+
+ // Reset old user provided lowerdir string
+ kfree(ctx->lowerdir_all);
+ ctx->lowerdir_all = NULL;
+
+ for (size_t nr = 0; nr < ctx->nr; nr++, l++) {
+ path_put(&l->path);
+ kfree(l->name);
+ l->name = NULL;
}
ctx->nr = 0;
ctx->nr_data = 0;
/*
* Parse lowerdir= mount option:
*
- * (1) lowerdir=/lower1:/lower2:/lower3::/data1::/data2
+ * e.g.: lowerdir=/lower1:/lower2:/lower3::/data1::/data2
* Set "/lower1", "/lower2", and "/lower3" as lower layers and
* "/data1" and "/data2" as data lower layers. Any existing lower
* layers are replaced.
int err;
struct ovl_fs_context *ctx = fc->fs_private;
struct ovl_fs_context_layer *l;
- char *dup = NULL, *dup_iter;
+ char *dup = NULL, *iter;
ssize_t nr_lower = 0, nr = 0, nr_data = 0;
- bool append = false, data_layer = false;
+ bool data_layer = false;
/*
* Ensure we're backwards compatible with mount(2)
*/
/* drop all existing lower layers */
- if (!*name) {
- ovl_parse_param_drop_lowerdir(ctx);
+ ovl_reset_lowerdirs(ctx);
+
+ if (!*name)
return 0;
- }
if (*name == ':') {
pr_err("cannot append lower layer");
return -EINVAL;
}
+ // Store user provided lowerdir string to show in mount options
+ ctx->lowerdir_all = kstrdup(name, GFP_KERNEL);
+ if (!ctx->lowerdir_all)
+ return -ENOMEM;
+
dup = kstrdup(name, GFP_KERNEL);
if (!dup)
return -ENOMEM;
if (nr_lower < 0)
goto out_err;
- if ((nr_lower > OVL_MAX_STACK) ||
- (append && (size_add(ctx->nr, nr_lower) > OVL_MAX_STACK))) {
+ if (nr_lower > OVL_MAX_STACK) {
pr_err("too many lower directories, limit is %d\n", OVL_MAX_STACK);
goto out_err;
}
- if (!append)
- ovl_parse_param_drop_lowerdir(ctx);
-
- /*
- * (1) append
- *
- * We want nr <= nr_lower <= capacity We know nr > 0 and nr <=
- * capacity. If nr == 0 this wouldn't be append. If nr +
- * nr_lower is <= capacity then nr <= nr_lower <= capacity
- * already holds. If nr + nr_lower exceeds capacity, we realloc.
- *
- * (2) replace
- *
- * Ensure we're backwards compatible with mount(2) which allows
- * "lowerdir=/a:/b:/c,lowerdir=/d:/e:/f" causing the last
- * specified lowerdir mount option to win.
- *
- * We want nr <= nr_lower <= capacity We know either (i) nr == 0
- * or (ii) nr > 0. We also know nr_lower > 0. The capacity
- * could've been changed multiple times already so we only know
- * nr <= capacity. If nr + nr_lower > capacity we realloc,
- * otherwise nr <= nr_lower <= capacity holds already.
- */
- nr_lower += ctx->nr;
if (nr_lower > ctx->capacity) {
err = -ENOMEM;
l = krealloc_array(ctx->lower, nr_lower, sizeof(*ctx->lower),
ctx->capacity = nr_lower;
}
- /*
- * (3) By (1) and (2) we know nr <= nr_lower <= capacity.
- * (4) If ctx->nr == 0 => replace
- * We have verified above that the lowerdir mount option
- * isn't an append, i.e., the lowerdir mount option
- * doesn't start with ":" or "::".
- * (4.1) The lowerdir mount options only contains regular lower
- * layers ":".
- * => Nothing to verify.
- * (4.2) The lowerdir mount options contains regular ":" and
- * data "::" layers.
- * => We need to verify that data lower layers "::" aren't
- * followed by regular ":" lower layers
- * (5) If ctx->nr > 0 => append
- * We know that there's at least one regular layer
- * otherwise we would've failed when parsing the previous
- * lowerdir mount option.
- * (5.1) The lowerdir mount option is a regular layer ":" append
- * => We need to verify that no data layers have been
- * specified before.
- * (5.2) The lowerdir mount option is a data layer "::" append
- * We know that there's at least one regular layer or
- * other data layers. => There's nothing to verify.
- */
- dup_iter = dup;
- for (nr = ctx->nr; nr < nr_lower; nr++) {
- l = &ctx->lower[nr];
+ iter = dup;
+ l = ctx->lower;
+ for (nr = 0; nr < nr_lower; nr++, l++) {
memset(l, 0, sizeof(*l));
- err = ovl_mount_dir(dup_iter, &l->path, false);
+ err = ovl_mount_dir(iter, &l->path);
+ if (err)
+ goto out_put;
+
+ err = ovl_mount_dir_check(fc, &l->path, Opt_lowerdir, iter, false);
if (err)
goto out_put;
err = -ENOMEM;
- l->name = kstrdup(dup_iter, GFP_KERNEL_ACCOUNT);
+ l->name = kstrdup(iter, GFP_KERNEL_ACCOUNT);
if (!l->name)
goto out_put;
break;
err = -EINVAL;
- dup_iter = strchr(dup_iter, '\0') + 1;
- if (*dup_iter) {
+ iter = strchr(iter, '\0') + 1;
+ if (*iter) {
/*
* This is a regular layer so we require that
* there are no data layers.
/* This is a data lower layer. */
data_layer = true;
- dup_iter++;
+ iter++;
}
ctx->nr = nr_lower;
ctx->nr_data += nr_data;
return 0;
out_put:
- /*
- * We know nr >= ctx->nr < nr_lower. If we failed somewhere
- * we want to undo until nr == ctx->nr. This is correct for
- * both ctx->nr == 0 and ctx->nr > 0.
- */
- for (; nr >= ctx->nr; nr--) {
- l = &ctx->lower[nr];
- kfree(l->name);
- l->name = NULL;
- path_put(&l->path);
-
- /* don't overflow */
- if (nr == 0)
- break;
- }
+ ovl_reset_lowerdirs(ctx);
out_err:
kfree(dup);
case Opt_lowerdir:
err = ovl_parse_param_lowerdir(param->string, fc);
break;
+ case Opt_lowerdir_add:
+ case Opt_datadir_add:
case Opt_upperdir:
- fallthrough;
case Opt_workdir:
- err = ovl_parse_param_upperdir(param->string, fc,
- (Opt_workdir == opt));
+ err = ovl_parse_layer(fc, param, opt);
break;
case Opt_default_permissions:
config->default_permissions = true;
static inline void ovl_fs_context_free(struct ovl_fs_context *ctx)
{
- ovl_parse_param_drop_lowerdir(ctx);
+ ovl_reset_lowerdirs(ctx);
path_put(&ctx->upper);
path_put(&ctx->work);
kfree(ctx->lower);
{
struct super_block *sb = dentry->d_sb;
struct ovl_fs *ofs = OVL_FS(sb);
- size_t nr, nr_merged_lower = ofs->numlayer - ofs->numdatalayer;
+ size_t nr, nr_merged_lower, nr_lower = 0;
+ char **lowerdirs = ofs->config.lowerdirs;
/*
- * lowerdirs[] starts from offset 1, then
- * >= 0 regular lower layers prefixed with : and
- * >= 0 data-only lower layers prefixed with ::
- *
- * we need to escase comma and space like seq_show_option() does and
- * we also need to escape the colon separator from lowerdir paths.
+ * lowerdirs[0] holds the colon separated list that user provided
+ * with lowerdir mount option.
+ * lowerdirs[1..numlayer] hold the lowerdir paths that were added
+ * using the lowerdir+ and datadir+ mount options.
+ * For now, we do not allow mixing the legacy lowerdir mount option
+ * with the new lowerdir+ and datadir+ mount options.
*/
- seq_puts(m, ",lowerdir=");
- for (nr = 1; nr < ofs->numlayer; nr++) {
- if (nr > 1)
- seq_putc(m, ':');
- if (nr >= nr_merged_lower)
- seq_putc(m, ':');
- seq_escape(m, ofs->config.lowerdirs[nr], ":, \t\n\\");
+ if (lowerdirs[0]) {
+ seq_show_option(m, "lowerdir", lowerdirs[0]);
+ } else {
+ nr_lower = ofs->numlayer;
+ nr_merged_lower = nr_lower - ofs->numdatalayer;
+ }
+ for (nr = 1; nr < nr_lower; nr++) {
+ if (nr < nr_merged_lower)
+ seq_show_option(m, "lowerdir+", lowerdirs[nr]);
+ else
+ seq_show_option(m, "datadir+", lowerdirs[nr]);
}
if (ofs->config.upperdir) {
seq_show_option(m, "upperdir", ofs->config.upperdir);
size_t nr_data;
struct ovl_opt_set set;
struct ovl_fs_context_layer *lower;
+ char *lowerdir_all; /* user provided lowerdir string */
};
int ovl_init_fs_context(struct fs_context *fc);
struct ovl_cache_entry *next_maybe_whiteout;
bool is_upper;
bool is_whiteout;
+ bool check_xwhiteout;
char name[];
};
int err;
bool is_upper;
bool d_type_supported;
+ bool in_xwhiteouts_dir;
};
struct ovl_dir_file {
p->ino = 0;
p->is_upper = rdd->is_upper;
p->is_whiteout = false;
+ /* Defer check for overlay.whiteout to ovl_iterate() */
+ p->check_xwhiteout = rdd->in_xwhiteouts_dir && d_type == DT_REG;
if (d_type == DT_CHR) {
p->next_maybe_whiteout = rdd->first_maybe_whiteout;
if (IS_ERR(realfile))
return PTR_ERR(realfile);
+ rdd->in_xwhiteouts_dir = rdd->dentry &&
+ ovl_path_check_xwhiteouts_xattr(OVL_FS(rdd->dentry->d_sb), realpath);
rdd->first_maybe_whiteout = NULL;
rdd->ctx.pos = 0;
do {
}
/*
- * Set d_ino for upper entries. Non-upper entries should always report
+ * Set d_ino for upper entries if needed. Non-upper entries should always report
* the uppermost real inode ino and should not call this function.
*
* When not all layer are on same fs, report real ino also for upper.
* When all layers are on the same fs, and upper has a reference to
* copy up origin, call vfs_getattr() on the overlay entry to make
* sure that d_ino will be consistent with st_ino from stat(2).
+ *
+ * Also checks the overlay.whiteout xattr by doing a full lookup which will return
+ * negative in this case.
*/
-static int ovl_cache_update_ino(const struct path *path, struct ovl_cache_entry *p)
+static int ovl_cache_update(const struct path *path, struct ovl_cache_entry *p, bool update_ino)
{
struct dentry *dir = path->dentry;
int xinobits = ovl_xino_bits(ofs);
int err = 0;
- if (!ovl_same_dev(ofs))
+ if (!ovl_same_dev(ofs) && !p->check_xwhiteout)
goto out;
if (p->name[0] == '.') {
goto get;
}
}
+ /* This checks also for xwhiteouts */
this = lookup_one(mnt_idmap(path->mnt), p->name, dir, p->len);
if (IS_ERR_OR_NULL(this) || !this->d_inode) {
/* Mark a stale entry */
}
get:
+ if (!ovl_same_dev(ofs) || !update_ino)
+ goto out;
+
type = ovl_path_type(this);
if (OVL_TYPE_ORIGIN(type)) {
struct kstat stat;
list_for_each_entry_safe(p, n, list, l_node) {
if (strcmp(p->name, ".") != 0 &&
strcmp(p->name, "..") != 0) {
- err = ovl_cache_update_ino(path, p);
+ err = ovl_cache_update(path, p, true);
if (err)
return err;
}
while (od->cursor != &od->cache->entries) {
p = list_entry(od->cursor, struct ovl_cache_entry, l_node);
if (!p->is_whiteout) {
- if (!p->ino) {
- err = ovl_cache_update_ino(&file->f_path, p);
+ if (!p->ino || p->check_xwhiteout) {
+ err = ovl_cache_update(&file->f_path, p, !p->ino);
if (err)
goto out;
}
}
- /* ovl_cache_update_ino() sets is_whiteout on stale entry */
+ /* ovl_cache_update() sets is_whiteout on stale entry */
if (!p->is_whiteout) {
if (!dir_emit(ctx, p->name, p->len, p->ino, p->type))
break;
return ok;
}
-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 -EOPNOTSUPP;
-}
-
-static int ovl_own_xattr_set(const struct xattr_handler *handler,
- struct mnt_idmap *idmap,
- struct dentry *dentry, struct inode *inode,
- const char *name, const void *value,
- size_t size, int flags)
-{
- return -EOPNOTSUPP;
-}
-
-static int ovl_other_xattr_get(const struct xattr_handler *handler,
- struct dentry *dentry, struct inode *inode,
- const char *name, void *buffer, size_t size)
-{
- return ovl_xattr_get(dentry, inode, name, buffer, size);
-}
-
-static int ovl_other_xattr_set(const struct xattr_handler *handler,
- struct mnt_idmap *idmap,
- struct dentry *dentry, struct inode *inode,
- const char *name, const void *value,
- size_t size, int flags)
-{
- return ovl_xattr_set(dentry, inode, name, value, size, flags);
-}
-
-static const struct xattr_handler ovl_own_trusted_xattr_handler = {
- .prefix = OVL_XATTR_TRUSTED_PREFIX,
- .get = ovl_own_xattr_get,
- .set = ovl_own_xattr_set,
-};
-
-static const struct xattr_handler ovl_own_user_xattr_handler = {
- .prefix = OVL_XATTR_USER_PREFIX,
- .get = ovl_own_xattr_get,
- .set = ovl_own_xattr_set,
-};
-
-static const struct xattr_handler ovl_other_xattr_handler = {
- .prefix = "", /* catch all */
- .get = ovl_other_xattr_get,
- .set = ovl_other_xattr_set,
-};
-
-static const struct xattr_handler * const ovl_trusted_xattr_handlers[] = {
- &ovl_own_trusted_xattr_handler,
- &ovl_other_xattr_handler,
- NULL
-};
-
-static const struct xattr_handler * const ovl_user_xattr_handlers[] = {
- &ovl_own_user_xattr_handler,
- &ovl_other_xattr_handler,
- NULL
-};
-
static int ovl_setup_trap(struct super_block *sb, struct dentry *dir,
struct inode **ptrap, const char *name)
{
if (IS_ERR(whiteout))
goto cleanup_temp;
- err = ovl_is_whiteout(whiteout);
+ err = ovl_upper_is_whiteout(ofs, whiteout);
/* Best effort cleanup of whiteout and temp file */
if (err)
{
struct vfsmount *mnt = ovl_upper_mnt(ofs);
struct dentry *indexdir;
+ struct dentry *origin = ovl_lowerstack(oe)->dentry;
+ const struct ovl_fh *fh;
int err;
+ fh = ovl_get_origin_fh(ofs, origin);
+ if (IS_ERR(fh))
+ return PTR_ERR(fh);
+
err = mnt_want_write(mnt);
if (err)
- return err;
+ goto out_free_fh;
/* Verify lower root is upper root origin */
- err = ovl_verify_origin(ofs, upperpath->dentry,
- ovl_lowerstack(oe)->dentry, true);
+ err = ovl_verify_origin_fh(ofs, upperpath->dentry, fh, true);
if (err) {
pr_err("failed to verify upper root origin\n");
goto out;
* directory entries.
*/
if (ovl_check_origin_xattr(ofs, ofs->indexdir)) {
- err = ovl_verify_set_fh(ofs, ofs->indexdir,
- OVL_XATTR_ORIGIN,
- upperpath->dentry, true, false);
+ err = ovl_verify_origin_xattr(ofs, ofs->indexdir,
+ OVL_XATTR_ORIGIN,
+ upperpath->dentry, true,
+ false);
if (err)
pr_err("failed to verify index dir 'origin' xattr\n");
}
out:
mnt_drop_write(mnt);
+out_free_fh:
+ kfree(fh);
return err;
}
ofs->layers = layers;
/*
* Layer 0 is reserved for upper even if there's no upper.
- * For consistency, config.lowerdirs[0] is NULL.
+ * config.lowerdirs[0] is used for storing the user provided colon
+ * separated lowerdir string.
*/
+ ofs->config.lowerdirs[0] = ctx->lowerdir_all;
+ ctx->lowerdir_all = NULL;
ofs->numlayer = 1;
sb->s_stack_depth = 0;
cap_lower(cred->cap_effective, CAP_SYS_RESOURCE);
sb->s_magic = OVERLAYFS_SUPER_MAGIC;
- sb->s_xattr = ofs->config.userxattr ? ovl_user_xattr_handlers :
- ovl_trusted_xattr_handlers;
+ sb->s_xattr = ovl_xattr_handlers(ofs);
sb->s_fs_info = ofs;
#ifdef CONFIG_FS_POSIX_ACL
sb->s_flags |= SB_POSIXACL;
#include <linux/ratelimit.h>
#include "overlayfs.h"
+/* Get write access to upper mnt - may fail if upper sb was remounted ro */
+int ovl_get_write_access(struct dentry *dentry)
+{
+ struct ovl_fs *ofs = OVL_FS(dentry->d_sb);
+ return mnt_get_write_access(ovl_upper_mnt(ofs));
+}
+
+/* Get write access to upper sb - may block if upper sb is frozen */
+void ovl_start_write(struct dentry *dentry)
+{
+ struct ovl_fs *ofs = OVL_FS(dentry->d_sb);
+ sb_start_write(ovl_upper_mnt(ofs)->mnt_sb);
+}
+
int ovl_want_write(struct dentry *dentry)
{
struct ovl_fs *ofs = OVL_FS(dentry->d_sb);
return mnt_want_write(ovl_upper_mnt(ofs));
}
+void ovl_put_write_access(struct dentry *dentry)
+{
+ struct ovl_fs *ofs = OVL_FS(dentry->d_sb);
+ mnt_put_write_access(ovl_upper_mnt(ofs));
+}
+
+void ovl_end_write(struct dentry *dentry)
+{
+ struct ovl_fs *ofs = OVL_FS(dentry->d_sb);
+ sb_end_write(ovl_upper_mnt(ofs)->mnt_sb);
+}
+
void ovl_drop_write(struct dentry *dentry)
{
struct ovl_fs *ofs = OVL_FS(dentry->d_sb);
return inode && IS_WHITEOUT(inode);
}
+/*
+ * Use this over ovl_is_whiteout for upper and lower files, as it also
+ * handles overlay.whiteout xattr whiteout files.
+ */
+bool ovl_path_is_whiteout(struct ovl_fs *ofs, const struct path *path)
+{
+ return ovl_is_whiteout(path->dentry) ||
+ ovl_path_check_xwhiteout_xattr(ofs, path);
+}
+
struct file *ovl_path_open(const struct path *path, int flags)
{
struct inode *inode = d_inode(path->dentry);
return false;
}
+/*
+ * The copy up "transaction" keeps an elevated mnt write count on upper mnt,
+ * but leaves taking freeze protection on upper sb to lower level helpers.
+ */
int ovl_copy_up_start(struct dentry *dentry, int flags)
{
struct inode *inode = d_inode(dentry);
int err;
err = ovl_inode_lock_interruptible(inode);
- if (!err && ovl_already_copied_up_locked(dentry, flags)) {
+ if (err)
+ return err;
+
+ if (ovl_already_copied_up_locked(dentry, flags))
err = 1; /* Already copied up */
- ovl_inode_unlock(inode);
- }
+ else
+ err = ovl_get_write_access(dentry);
+ if (err)
+ goto out_unlock;
+
+ return 0;
+out_unlock:
+ ovl_inode_unlock(inode);
return err;
}
void ovl_copy_up_end(struct dentry *dentry)
{
+ ovl_put_write_access(dentry);
ovl_inode_unlock(d_inode(dentry));
}
return false;
}
+bool ovl_path_check_xwhiteout_xattr(struct ovl_fs *ofs, const struct path *path)
+{
+ struct dentry *dentry = path->dentry;
+ int res;
+
+ /* xattr.whiteout must be a zero size regular file */
+ if (!d_is_reg(dentry) || i_size_read(d_inode(dentry)) != 0)
+ return false;
+
+ res = ovl_path_getxattr(ofs, path, OVL_XATTR_XWHITEOUT, NULL, 0);
+ return res >= 0;
+}
+
+bool ovl_path_check_xwhiteouts_xattr(struct ovl_fs *ofs, const struct path *path)
+{
+ struct dentry *dentry = path->dentry;
+ int res;
+
+ /* xattr.whiteouts must be a directory */
+ if (!d_is_dir(dentry))
+ return false;
+
+ res = ovl_path_getxattr(ofs, path, OVL_XATTR_XWHITEOUTS, NULL, 0);
+ return res >= 0;
+}
+
/*
* Load persistent uuid from xattr into s_uuid if found, or store a new
* random generated value in s_uuid and in xattr.
#define OVL_XATTR_UUID_POSTFIX "uuid"
#define OVL_XATTR_METACOPY_POSTFIX "metacopy"
#define OVL_XATTR_PROTATTR_POSTFIX "protattr"
+#define OVL_XATTR_XWHITEOUT_POSTFIX "whiteout"
+#define OVL_XATTR_XWHITEOUTS_POSTFIX "whiteouts"
#define OVL_XATTR_TAB_ENTRY(x) \
[x] = { [false] = OVL_XATTR_TRUSTED_PREFIX x ## _POSTFIX, \
OVL_XATTR_TAB_ENTRY(OVL_XATTR_UUID),
OVL_XATTR_TAB_ENTRY(OVL_XATTR_METACOPY),
OVL_XATTR_TAB_ENTRY(OVL_XATTR_PROTATTR),
+ OVL_XATTR_TAB_ENTRY(OVL_XATTR_XWHITEOUT),
+ OVL_XATTR_TAB_ENTRY(OVL_XATTR_XWHITEOUTS),
};
int ovl_check_setxattr(struct ovl_fs *ofs, struct dentry *upperdentry,
struct dentry *index = NULL;
struct inode *inode;
struct qstr name = { };
+ bool got_write = false;
int err;
err = ovl_get_index_name(ofs, lowerdentry, &name);
if (err)
goto fail;
+ err = ovl_want_write(dentry);
+ if (err)
+ goto fail;
+
+ got_write = true;
inode = d_inode(upperdentry);
if (!S_ISDIR(inode->i_mode) && inode->i_nlink != 1) {
pr_warn_ratelimited("cleanup linked index (%pd2, ino=%lu, nlink=%u)\n",
goto fail;
out:
+ if (got_write)
+ ovl_drop_write(dentry);
kfree(name.name);
dput(index);
return;
if (err)
return err;
+ err = ovl_want_write(dentry);
+ if (err)
+ goto out_unlock;
+
if (d_is_dir(dentry) || !ovl_test_flag(OVL_INDEX, inode))
- goto out;
+ return 0;
old_cred = ovl_override_creds(dentry->d_sb);
/*
*/
err = ovl_set_nlink_upper(dentry);
revert_creds(old_cred);
-
-out:
if (err)
- ovl_inode_unlock(inode);
+ goto out_drop_write;
+
+ return 0;
+
+out_drop_write:
+ ovl_drop_write(dentry);
+out_unlock:
+ ovl_inode_unlock(inode);
return err;
}
{
struct inode *inode = d_inode(dentry);
+ ovl_drop_write(dentry);
+
if (ovl_test_flag(OVL_INDEX, inode) && inode->i_nlink == 0) {
const struct cred *old_cred;
realinode = ovl_i_path_real(inode, &realpath);
real_idmap = mnt_idmap(realpath.mnt);
+ spin_lock(&inode->i_lock);
vfsuid = i_uid_into_vfsuid(real_idmap, realinode);
vfsgid = i_gid_into_vfsgid(real_idmap, realinode);
inode_set_mtime_to_ts(inode, inode_get_mtime(realinode));
inode_set_ctime_to_ts(inode, inode_get_ctime(realinode));
i_size_write(inode, i_size_read(realinode));
+ spin_unlock(&inode->i_lock);
}
--- /dev/null
+// SPDX-License-Identifier: GPL-2.0-only
+
+#include <linux/fs.h>
+#include <linux/xattr.h>
+#include "overlayfs.h"
+
+static bool ovl_is_escaped_xattr(struct super_block *sb, const char *name)
+{
+ struct ovl_fs *ofs = sb->s_fs_info;
+
+ if (ofs->config.userxattr)
+ return strncmp(name, OVL_XATTR_ESCAPE_USER_PREFIX,
+ OVL_XATTR_ESCAPE_USER_PREFIX_LEN) == 0;
+ else
+ return strncmp(name, OVL_XATTR_ESCAPE_TRUSTED_PREFIX,
+ OVL_XATTR_ESCAPE_TRUSTED_PREFIX_LEN - 1) == 0;
+}
+
+static bool ovl_is_own_xattr(struct super_block *sb, const char *name)
+{
+ struct ovl_fs *ofs = OVL_FS(sb);
+
+ if (ofs->config.userxattr)
+ return strncmp(name, OVL_XATTR_USER_PREFIX,
+ OVL_XATTR_USER_PREFIX_LEN) == 0;
+ else
+ return strncmp(name, OVL_XATTR_TRUSTED_PREFIX,
+ OVL_XATTR_TRUSTED_PREFIX_LEN) == 0;
+}
+
+bool ovl_is_private_xattr(struct super_block *sb, const char *name)
+{
+ return ovl_is_own_xattr(sb, name) && !ovl_is_escaped_xattr(sb, name);
+}
+
+static int ovl_xattr_set(struct dentry *dentry, struct inode *inode, const char *name,
+ const void *value, size_t size, int flags)
+{
+ int err;
+ struct ovl_fs *ofs = OVL_FS(dentry->d_sb);
+ struct dentry *upperdentry = ovl_i_dentry_upper(inode);
+ struct dentry *realdentry = upperdentry ?: ovl_dentry_lower(dentry);
+ struct path realpath;
+ const struct cred *old_cred;
+
+ if (!value && !upperdentry) {
+ ovl_path_lower(dentry, &realpath);
+ old_cred = ovl_override_creds(dentry->d_sb);
+ err = vfs_getxattr(mnt_idmap(realpath.mnt), realdentry, name, NULL, 0);
+ revert_creds(old_cred);
+ if (err < 0)
+ goto out;
+ }
+
+ if (!upperdentry) {
+ err = ovl_copy_up(dentry);
+ if (err)
+ goto out;
+
+ realdentry = ovl_dentry_upper(dentry);
+ }
+
+ err = ovl_want_write(dentry);
+ if (err)
+ goto out;
+
+ old_cred = ovl_override_creds(dentry->d_sb);
+ if (value) {
+ err = ovl_do_setxattr(ofs, realdentry, name, value, size,
+ flags);
+ } else {
+ WARN_ON(flags != XATTR_REPLACE);
+ err = ovl_do_removexattr(ofs, realdentry, name);
+ }
+ revert_creds(old_cred);
+ ovl_drop_write(dentry);
+
+ /* copy c/mtime */
+ ovl_copyattr(inode);
+out:
+ return err;
+}
+
+static int ovl_xattr_get(struct dentry *dentry, struct inode *inode, const char *name,
+ void *value, size_t size)
+{
+ ssize_t res;
+ const struct cred *old_cred;
+ struct path realpath;
+
+ ovl_i_path_real(inode, &realpath);
+ old_cred = ovl_override_creds(dentry->d_sb);
+ res = vfs_getxattr(mnt_idmap(realpath.mnt), realpath.dentry, name, value, size);
+ revert_creds(old_cred);
+ return res;
+}
+
+static bool ovl_can_list(struct super_block *sb, const char *s)
+{
+ /* Never list private (.overlay) */
+ if (ovl_is_private_xattr(sb, s))
+ return false;
+
+ /* List all non-trusted xattrs */
+ if (strncmp(s, XATTR_TRUSTED_PREFIX, XATTR_TRUSTED_PREFIX_LEN) != 0)
+ return true;
+
+ /* list other trusted for superuser only */
+ return ns_capable_noaudit(&init_user_ns, CAP_SYS_ADMIN);
+}
+
+ssize_t ovl_listxattr(struct dentry *dentry, char *list, size_t size)
+{
+ struct dentry *realdentry = ovl_dentry_real(dentry);
+ struct ovl_fs *ofs = OVL_FS(dentry->d_sb);
+ ssize_t res;
+ size_t len;
+ char *s;
+ const struct cred *old_cred;
+ size_t prefix_len, name_len;
+
+ old_cred = ovl_override_creds(dentry->d_sb);
+ res = vfs_listxattr(realdentry, list, size);
+ revert_creds(old_cred);
+ if (res <= 0 || size == 0)
+ return res;
+
+ prefix_len = ofs->config.userxattr ?
+ OVL_XATTR_USER_PREFIX_LEN : OVL_XATTR_TRUSTED_PREFIX_LEN;
+
+ /* filter out private xattrs */
+ for (s = list, len = res; len;) {
+ size_t slen = strnlen(s, len) + 1;
+
+ /* underlying fs providing us with an broken xattr list? */
+ if (WARN_ON(slen > len))
+ return -EIO;
+
+ len -= slen;
+ if (!ovl_can_list(dentry->d_sb, s)) {
+ res -= slen;
+ memmove(s, s + slen, len);
+ } else if (ovl_is_escaped_xattr(dentry->d_sb, s)) {
+ res -= OVL_XATTR_ESCAPE_PREFIX_LEN;
+ name_len = slen - prefix_len - OVL_XATTR_ESCAPE_PREFIX_LEN;
+ s += prefix_len;
+ memmove(s, s + OVL_XATTR_ESCAPE_PREFIX_LEN, name_len + len);
+ s += name_len;
+ } else {
+ s += slen;
+ }
+ }
+
+ return res;
+}
+
+static char *ovl_xattr_escape_name(const char *prefix, const char *name)
+{
+ size_t prefix_len = strlen(prefix);
+ size_t name_len = strlen(name);
+ size_t escaped_len;
+ char *escaped, *s;
+
+ escaped_len = prefix_len + OVL_XATTR_ESCAPE_PREFIX_LEN + name_len;
+ if (escaped_len > XATTR_NAME_MAX)
+ return ERR_PTR(-EOPNOTSUPP);
+
+ escaped = kmalloc(escaped_len + 1, GFP_KERNEL);
+ if (escaped == NULL)
+ return ERR_PTR(-ENOMEM);
+
+ s = escaped;
+ memcpy(s, prefix, prefix_len);
+ s += prefix_len;
+ memcpy(s, OVL_XATTR_ESCAPE_PREFIX, OVL_XATTR_ESCAPE_PREFIX_LEN);
+ s += OVL_XATTR_ESCAPE_PREFIX_LEN;
+ memcpy(s, name, name_len + 1);
+
+ return escaped;
+}
+
+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)
+{
+ char *escaped;
+ int r;
+
+ escaped = ovl_xattr_escape_name(handler->prefix, name);
+ if (IS_ERR(escaped))
+ return PTR_ERR(escaped);
+
+ r = ovl_xattr_get(dentry, inode, escaped, buffer, size);
+
+ kfree(escaped);
+
+ return r;
+}
+
+static int ovl_own_xattr_set(const struct xattr_handler *handler,
+ struct mnt_idmap *idmap,
+ struct dentry *dentry, struct inode *inode,
+ const char *name, const void *value,
+ size_t size, int flags)
+{
+ char *escaped;
+ int r;
+
+ escaped = ovl_xattr_escape_name(handler->prefix, name);
+ if (IS_ERR(escaped))
+ return PTR_ERR(escaped);
+
+ r = ovl_xattr_set(dentry, inode, escaped, value, size, flags);
+
+ kfree(escaped);
+
+ return r;
+}
+
+static int ovl_other_xattr_get(const struct xattr_handler *handler,
+ struct dentry *dentry, struct inode *inode,
+ const char *name, void *buffer, size_t size)
+{
+ return ovl_xattr_get(dentry, inode, name, buffer, size);
+}
+
+static int ovl_other_xattr_set(const struct xattr_handler *handler,
+ struct mnt_idmap *idmap,
+ struct dentry *dentry, struct inode *inode,
+ const char *name, const void *value,
+ size_t size, int flags)
+{
+ return ovl_xattr_set(dentry, inode, name, value, size, flags);
+}
+
+static const struct xattr_handler ovl_own_trusted_xattr_handler = {
+ .prefix = OVL_XATTR_TRUSTED_PREFIX,
+ .get = ovl_own_xattr_get,
+ .set = ovl_own_xattr_set,
+};
+
+static const struct xattr_handler ovl_own_user_xattr_handler = {
+ .prefix = OVL_XATTR_USER_PREFIX,
+ .get = ovl_own_xattr_get,
+ .set = ovl_own_xattr_set,
+};
+
+static const struct xattr_handler ovl_other_xattr_handler = {
+ .prefix = "", /* catch all */
+ .get = ovl_other_xattr_get,
+ .set = ovl_other_xattr_set,
+};
+
+static const struct xattr_handler * const ovl_trusted_xattr_handlers[] = {
+ &ovl_own_trusted_xattr_handler,
+ &ovl_other_xattr_handler,
+ NULL
+};
+
+static const struct xattr_handler * const ovl_user_xattr_handlers[] = {
+ &ovl_own_user_xattr_handler,
+ &ovl_other_xattr_handler,
+ NULL
+};
+
+const struct xattr_handler * const *ovl_xattr_handlers(struct ovl_fs *ofs)
+{
+ return ofs->config.userxattr ? ovl_user_xattr_handlers :
+ ovl_trusted_xattr_handlers;
+}
+
destroy_workqueue(wq);
return 0;
}
+EXPORT_SYMBOL_GPL(sb_init_dio_done_wq);
projects / linux-2.6-microblaze.git / commitdiff