Adding upstream version 6.1.76.upstream/6.1.76

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1037 insertions, 0 deletions

diff --git a/fs/reiserfs/xattr.c b/fs/reiserfs/xattr.c
new file mode 100644
index 000000000..8b2d52443
--- /dev/null
+++ b/fs/reiserfs/xattr.c
@@ -0,0 +1,1037 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * linux/fs/reiserfs/xattr.c
+ *
+ * Copyright (c) 2002 by Jeff Mahoney, <jeffm@suse.com>
+ *
+ */
+
+/*
+ * In order to implement EA/ACLs in a clean, backwards compatible manner,
+ * they are implemented as files in a "private" directory.
+ * Each EA is in it's own file, with the directory layout like so (/ is assumed
+ * to be relative to fs root). Inside the /.reiserfs_priv/xattrs directory,
+ * directories named using the capital-hex form of the objectid and
+ * generation number are used. Inside each directory are individual files
+ * named with the name of the extended attribute.
+ *
+ * So, for objectid 12648430, we could have:
+ * /.reiserfs_priv/xattrs/C0FFEE.0/system.posix_acl_access
+ * /.reiserfs_priv/xattrs/C0FFEE.0/system.posix_acl_default
+ * /.reiserfs_priv/xattrs/C0FFEE.0/user.Content-Type
+ * .. or similar.
+ *
+ * The file contents are the text of the EA. The size is known based on the
+ * stat data describing the file.
+ *
+ * In the case of system.posix_acl_access and system.posix_acl_default, since
+ * these are special cases for filesystem ACLs, they are interpreted by the
+ * kernel, in addition, they are negatively and positively cached and attached
+ * to the inode so that unnecessary lookups are avoided.
+ *
+ * Locking works like so:
+ * Directory components (xattr root, xattr dir) are protectd by their i_mutex.
+ * The xattrs themselves are protected by the xattr_sem.
+ */
+
+#include "reiserfs.h"
+#include <linux/capability.h>
+#include <linux/dcache.h>
+#include <linux/namei.h>
+#include <linux/errno.h>
+#include <linux/gfp.h>
+#include <linux/fs.h>
+#include <linux/file.h>
+#include <linux/pagemap.h>
+#include <linux/xattr.h>
+#include "xattr.h"
+#include "acl.h"
+#include <linux/uaccess.h>
+#include <net/checksum.h>
+#include <linux/stat.h>
+#include <linux/quotaops.h>
+#include <linux/security.h>
+#include <linux/posix_acl_xattr.h>
+
+#define PRIVROOT_NAME ".reiserfs_priv"
+#define XAROOT_NAME   "xattrs"
+
+
+/*
+ * Helpers for inode ops. We do this so that we don't have all the VFS
+ * overhead and also for proper i_mutex annotation.
+ * dir->i_mutex must be held for all of them.
+ */
+#ifdef CONFIG_REISERFS_FS_XATTR
+static int xattr_create(struct inode *dir, struct dentry *dentry, int mode)
+{
+	BUG_ON(!inode_is_locked(dir));
+	return dir->i_op->create(&init_user_ns, dir, dentry, mode, true);
+}
+#endif
+
+static int xattr_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
+{
+	BUG_ON(!inode_is_locked(dir));
+	return dir->i_op->mkdir(&init_user_ns, dir, dentry, mode);
+}
+
+/*
+ * We use I_MUTEX_CHILD here to silence lockdep. It's safe because xattr
+ * mutation ops aren't called during rename or splace, which are the
+ * only other users of I_MUTEX_CHILD. It violates the ordering, but that's
+ * better than allocating another subclass just for this code.
+ */
+static int xattr_unlink(struct inode *dir, struct dentry *dentry)
+{
+	int error;
+
+	BUG_ON(!inode_is_locked(dir));
+
+	inode_lock_nested(d_inode(dentry), I_MUTEX_CHILD);
+	error = dir->i_op->unlink(dir, dentry);
+	inode_unlock(d_inode(dentry));
+
+	if (!error)
+		d_delete(dentry);
+	return error;
+}
+
+static int xattr_rmdir(struct inode *dir, struct dentry *dentry)
+{
+	int error;
+
+	BUG_ON(!inode_is_locked(dir));
+
+	inode_lock_nested(d_inode(dentry), I_MUTEX_CHILD);
+	error = dir->i_op->rmdir(dir, dentry);
+	if (!error)
+		d_inode(dentry)->i_flags |= S_DEAD;
+	inode_unlock(d_inode(dentry));
+	if (!error)
+		d_delete(dentry);
+
+	return error;
+}
+
+#define xattr_may_create(flags)	(!flags || flags & XATTR_CREATE)
+
+static struct dentry *open_xa_root(struct super_block *sb, int flags)
+{
+	struct dentry *privroot = REISERFS_SB(sb)->priv_root;
+	struct dentry *xaroot;
+
+	if (d_really_is_negative(privroot))
+		return ERR_PTR(-EOPNOTSUPP);
+
+	inode_lock_nested(d_inode(privroot), I_MUTEX_XATTR);
+
+	xaroot = dget(REISERFS_SB(sb)->xattr_root);
+	if (!xaroot)
+		xaroot = ERR_PTR(-EOPNOTSUPP);
+	else if (d_really_is_negative(xaroot)) {
+		int err = -ENODATA;
+
+		if (xattr_may_create(flags))
+			err = xattr_mkdir(d_inode(privroot), xaroot, 0700);
+		if (err) {
+			dput(xaroot);
+			xaroot = ERR_PTR(err);
+		}
+	}
+
+	inode_unlock(d_inode(privroot));
+	return xaroot;
+}
+
+static struct dentry *open_xa_dir(const struct inode *inode, int flags)
+{
+	struct dentry *xaroot, *xadir;
+	char namebuf[17];
+
+	xaroot = open_xa_root(inode->i_sb, flags);
+	if (IS_ERR(xaroot))
+		return xaroot;
+
+	snprintf(namebuf, sizeof(namebuf), "%X.%X",
+		 le32_to_cpu(INODE_PKEY(inode)->k_objectid),
+		 inode->i_generation);
+
+	inode_lock_nested(d_inode(xaroot), I_MUTEX_XATTR);
+
+	xadir = lookup_one_len(namebuf, xaroot, strlen(namebuf));
+	if (!IS_ERR(xadir) && d_really_is_negative(xadir)) {
+		int err = -ENODATA;
+
+		if (xattr_may_create(flags))
+			err = xattr_mkdir(d_inode(xaroot), xadir, 0700);
+		if (err) {
+			dput(xadir);
+			xadir = ERR_PTR(err);
+		}
+	}
+
+	inode_unlock(d_inode(xaroot));
+	dput(xaroot);
+	return xadir;
+}
+
+/*
+ * The following are side effects of other operations that aren't explicitly
+ * modifying extended attributes. This includes operations such as permissions
+ * or ownership changes, object deletions, etc.
+ */
+struct reiserfs_dentry_buf {
+	struct dir_context ctx;
+	struct dentry *xadir;
+	int count;
+	int err;
+	struct dentry *dentries[8];
+};
+
+static bool
+fill_with_dentries(struct dir_context *ctx, const char *name, int namelen,
+		   loff_t offset, u64 ino, unsigned int d_type)
+{
+	struct reiserfs_dentry_buf *dbuf =
+		container_of(ctx, struct reiserfs_dentry_buf, ctx);
+	struct dentry *dentry;
+
+	WARN_ON_ONCE(!inode_is_locked(d_inode(dbuf->xadir)));
+
+	if (dbuf->count == ARRAY_SIZE(dbuf->dentries))
+		return false;
+
+	if (name[0] == '.' && (namelen < 2 ||
+			       (namelen == 2 && name[1] == '.')))
+		return true;
+
+	dentry = lookup_one_len(name, dbuf->xadir, namelen);
+	if (IS_ERR(dentry)) {
+		dbuf->err = PTR_ERR(dentry);
+		return false;
+	} else if (d_really_is_negative(dentry)) {
+		/* A directory entry exists, but no file? */
+		reiserfs_error(dentry->d_sb, "xattr-20003",
+			       "Corrupted directory: xattr %pd listed but "
+			       "not found for file %pd.\n",
+			       dentry, dbuf->xadir);
+		dput(dentry);
+		dbuf->err = -EIO;
+		return false;
+	}
+
+	dbuf->dentries[dbuf->count++] = dentry;
+	return true;
+}
+
+static void
+cleanup_dentry_buf(struct reiserfs_dentry_buf *buf)
+{
+	int i;
+
+	for (i = 0; i < buf->count; i++)
+		if (buf->dentries[i])
+			dput(buf->dentries[i]);
+}
+
+static int reiserfs_for_each_xattr(struct inode *inode,
+				   int (*action)(struct dentry *, void *),
+				   void *data)
+{
+	struct dentry *dir;
+	int i, err = 0;
+	struct reiserfs_dentry_buf buf = {
+		.ctx.actor = fill_with_dentries,
+	};
+
+	/* Skip out, an xattr has no xattrs associated with it */
+	if (IS_PRIVATE(inode) || get_inode_sd_version(inode) == STAT_DATA_V1)
+		return 0;
+
+	dir = open_xa_dir(inode, XATTR_REPLACE);
+	if (IS_ERR(dir)) {
+		err = PTR_ERR(dir);
+		goto out;
+	} else if (d_really_is_negative(dir)) {
+		err = 0;
+		goto out_dir;
+	}
+
+	inode_lock_nested(d_inode(dir), I_MUTEX_XATTR);
+
+	buf.xadir = dir;
+	while (1) {
+		err = reiserfs_readdir_inode(d_inode(dir), &buf.ctx);
+		if (err)
+			break;
+		if (buf.err) {
+			err = buf.err;
+			break;
+		}
+		if (!buf.count)
+			break;
+		for (i = 0; !err && i < buf.count && buf.dentries[i]; i++) {
+			struct dentry *dentry = buf.dentries[i];
+
+			if (!d_is_dir(dentry))
+				err = action(dentry, data);
+
+			dput(dentry);
+			buf.dentries[i] = NULL;
+		}
+		if (err)
+			break;
+		buf.count = 0;
+	}
+	inode_unlock(d_inode(dir));
+
+	cleanup_dentry_buf(&buf);
+
+	if (!err) {
+		/*
+		 * We start a transaction here to avoid a ABBA situation
+		 * between the xattr root's i_mutex and the journal lock.
+		 * This doesn't incur much additional overhead since the
+		 * new transaction will just nest inside the
+		 * outer transaction.
+		 */
+		int blocks = JOURNAL_PER_BALANCE_CNT * 2 + 2 +
+			     4 * REISERFS_QUOTA_TRANS_BLOCKS(inode->i_sb);
+		struct reiserfs_transaction_handle th;
+
+		reiserfs_write_lock(inode->i_sb);
+		err = journal_begin(&th, inode->i_sb, blocks);
+		reiserfs_write_unlock(inode->i_sb);
+		if (!err) {
+			int jerror;
+
+			inode_lock_nested(d_inode(dir->d_parent),
+					  I_MUTEX_XATTR);
+			err = action(dir, data);
+			reiserfs_write_lock(inode->i_sb);
+			jerror = journal_end(&th);
+			reiserfs_write_unlock(inode->i_sb);
+			inode_unlock(d_inode(dir->d_parent));
+			err = jerror ?: err;
+		}
+	}
+out_dir:
+	dput(dir);
+out:
+	/*
+	 * -ENODATA: this object doesn't have any xattrs
+	 * -EOPNOTSUPP: this file system doesn't have xattrs enabled on disk.
+	 * Neither are errors
+	 */
+	if (err == -ENODATA || err == -EOPNOTSUPP)
+		err = 0;
+	return err;
+}
+
+static int delete_one_xattr(struct dentry *dentry, void *data)
+{
+	struct inode *dir = d_inode(dentry->d_parent);
+
+	/* This is the xattr dir, handle specially. */
+	if (d_is_dir(dentry))
+		return xattr_rmdir(dir, dentry);
+
+	return xattr_unlink(dir, dentry);
+}
+
+static int chown_one_xattr(struct dentry *dentry, void *data)
+{
+	struct iattr *attrs = data;
+	int ia_valid = attrs->ia_valid;
+	int err;
+
+	/*
+	 * We only want the ownership bits. Otherwise, we'll do
+	 * things like change a directory to a regular file if
+	 * ATTR_MODE is set.
+	 */
+	attrs->ia_valid &= (ATTR_UID|ATTR_GID);
+	err = reiserfs_setattr(&init_user_ns, dentry, attrs);
+	attrs->ia_valid = ia_valid;
+
+	return err;
+}
+
+/* No i_mutex, but the inode is unconnected. */
+int reiserfs_delete_xattrs(struct inode *inode)
+{
+	int err = reiserfs_for_each_xattr(inode, delete_one_xattr, NULL);
+
+	if (err)
+		reiserfs_warning(inode->i_sb, "jdm-20004",
+				 "Couldn't delete all xattrs (%d)\n", err);
+	return err;
+}
+
+/* inode->i_mutex: down */
+int reiserfs_chown_xattrs(struct inode *inode, struct iattr *attrs)
+{
+	int err = reiserfs_for_each_xattr(inode, chown_one_xattr, attrs);
+
+	if (err)
+		reiserfs_warning(inode->i_sb, "jdm-20007",
+				 "Couldn't chown all xattrs (%d)\n", err);
+	return err;
+}
+
+#ifdef CONFIG_REISERFS_FS_XATTR
+/*
+ * Returns a dentry corresponding to a specific extended attribute file
+ * for the inode. If flags allow, the file is created. Otherwise, a
+ * valid or negative dentry, or an error is returned.
+ */
+static struct dentry *xattr_lookup(struct inode *inode, const char *name,
+				    int flags)
+{
+	struct dentry *xadir, *xafile;
+	int err = 0;
+
+	xadir = open_xa_dir(inode, flags);
+	if (IS_ERR(xadir))
+		return ERR_CAST(xadir);
+
+	inode_lock_nested(d_inode(xadir), I_MUTEX_XATTR);
+	xafile = lookup_one_len(name, xadir, strlen(name));
+	if (IS_ERR(xafile)) {
+		err = PTR_ERR(xafile);
+		goto out;
+	}
+
+	if (d_really_is_positive(xafile) && (flags & XATTR_CREATE))
+		err = -EEXIST;
+
+	if (d_really_is_negative(xafile)) {
+		err = -ENODATA;
+		if (xattr_may_create(flags))
+			err = xattr_create(d_inode(xadir), xafile,
+					      0700|S_IFREG);
+	}
+
+	if (err)
+		dput(xafile);
+out:
+	inode_unlock(d_inode(xadir));
+	dput(xadir);
+	if (err)
+		return ERR_PTR(err);
+	return xafile;
+}
+
+/* Internal operations on file data */
+static inline void reiserfs_put_page(struct page *page)
+{
+	kunmap(page);
+	put_page(page);
+}
+
+static struct page *reiserfs_get_page(struct inode *dir, size_t n)
+{
+	struct address_space *mapping = dir->i_mapping;
+	struct page *page;
+	/*
+	 * We can deadlock if we try to free dentries,
+	 * and an unlink/rmdir has just occurred - GFP_NOFS avoids this
+	 */
+	mapping_set_gfp_mask(mapping, GFP_NOFS);
+	page = read_mapping_page(mapping, n >> PAGE_SHIFT, NULL);
+	if (!IS_ERR(page))
+		kmap(page);
+	return page;
+}
+
+static inline __u32 xattr_hash(const char *msg, int len)
+{
+	/*
+	 * csum_partial() gives different results for little-endian and
+	 * big endian hosts. Images created on little-endian hosts and
+	 * mounted on big-endian hosts(and vice versa) will see csum mismatches
+	 * when trying to fetch xattrs. Treating the hash as __wsum_t would
+	 * lower the frequency of mismatch.  This is an endianness bug in
+	 * reiserfs.  The return statement would result in a sparse warning. Do
+	 * not fix the sparse warning so as to not hide a reminder of the bug.
+	 */
+	return csum_partial(msg, len, 0);
+}
+
+int reiserfs_commit_write(struct file *f, struct page *page,
+			  unsigned from, unsigned to);
+
+static void update_ctime(struct inode *inode)
+{
+	struct timespec64 now = current_time(inode);
+
+	if (inode_unhashed(inode) || !inode->i_nlink ||
+	    timespec64_equal(&inode->i_ctime, &now))
+		return;
+
+	inode->i_ctime = current_time(inode);
+	mark_inode_dirty(inode);
+}
+
+static int lookup_and_delete_xattr(struct inode *inode, const char *name)
+{
+	int err = 0;
+	struct dentry *dentry, *xadir;
+
+	xadir = open_xa_dir(inode, XATTR_REPLACE);
+	if (IS_ERR(xadir))
+		return PTR_ERR(xadir);
+
+	inode_lock_nested(d_inode(xadir), I_MUTEX_XATTR);
+	dentry = lookup_one_len(name, xadir, strlen(name));
+	if (IS_ERR(dentry)) {
+		err = PTR_ERR(dentry);
+		goto out_dput;
+	}
+
+	if (d_really_is_positive(dentry)) {
+		err = xattr_unlink(d_inode(xadir), dentry);
+		update_ctime(inode);
+	}
+
+	dput(dentry);
+out_dput:
+	inode_unlock(d_inode(xadir));
+	dput(xadir);
+	return err;
+}
+
+
+/* Generic extended attribute operations that can be used by xa plugins */
+
+/*
+ * inode->i_mutex: down
+ */
+int
+reiserfs_xattr_set_handle(struct reiserfs_transaction_handle *th,
+			  struct inode *inode, const char *name,
+			  const void *buffer, size_t buffer_size, int flags)
+{
+	int err = 0;
+	struct dentry *dentry;
+	struct page *page;
+	char *data;
+	size_t file_pos = 0;
+	size_t buffer_pos = 0;
+	size_t new_size;
+	__u32 xahash = 0;
+
+	if (get_inode_sd_version(inode) == STAT_DATA_V1)
+		return -EOPNOTSUPP;
+
+	if (!buffer) {
+		err = lookup_and_delete_xattr(inode, name);
+		return err;
+	}
+
+	dentry = xattr_lookup(inode, name, flags);
+	if (IS_ERR(dentry))
+		return PTR_ERR(dentry);
+
+	down_write(&REISERFS_I(inode)->i_xattr_sem);
+
+	xahash = xattr_hash(buffer, buffer_size);
+	while (buffer_pos < buffer_size || buffer_pos == 0) {
+		size_t chunk;
+		size_t skip = 0;
+		size_t page_offset = (file_pos & (PAGE_SIZE - 1));
+
+		if (buffer_size - buffer_pos > PAGE_SIZE)
+			chunk = PAGE_SIZE;
+		else
+			chunk = buffer_size - buffer_pos;
+
+		page = reiserfs_get_page(d_inode(dentry), file_pos);
+		if (IS_ERR(page)) {
+			err = PTR_ERR(page);
+			goto out_unlock;
+		}
+
+		lock_page(page);
+		data = page_address(page);
+
+		if (file_pos == 0) {
+			struct reiserfs_xattr_header *rxh;
+
+			skip = file_pos = sizeof(struct reiserfs_xattr_header);
+			if (chunk + skip > PAGE_SIZE)
+				chunk = PAGE_SIZE - skip;
+			rxh = (struct reiserfs_xattr_header *)data;
+			rxh->h_magic = cpu_to_le32(REISERFS_XATTR_MAGIC);
+			rxh->h_hash = cpu_to_le32(xahash);
+		}
+
+		reiserfs_write_lock(inode->i_sb);
+		err = __reiserfs_write_begin(page, page_offset, chunk + skip);
+		if (!err) {
+			if (buffer)
+				memcpy(data + skip, buffer + buffer_pos, chunk);
+			err = reiserfs_commit_write(NULL, page, page_offset,
+						    page_offset + chunk +
+						    skip);
+		}
+		reiserfs_write_unlock(inode->i_sb);
+		unlock_page(page);
+		reiserfs_put_page(page);
+		buffer_pos += chunk;
+		file_pos += chunk;
+		skip = 0;
+		if (err || buffer_size == 0 || !buffer)
+			break;
+	}
+
+	new_size = buffer_size + sizeof(struct reiserfs_xattr_header);
+	if (!err && new_size < i_size_read(d_inode(dentry))) {
+		struct iattr newattrs = {
+			.ia_ctime = current_time(inode),
+			.ia_size = new_size,
+			.ia_valid = ATTR_SIZE | ATTR_CTIME,
+		};
+
+		inode_lock_nested(d_inode(dentry), I_MUTEX_XATTR);
+		inode_dio_wait(d_inode(dentry));
+
+		err = reiserfs_setattr(&init_user_ns, dentry, &newattrs);
+		inode_unlock(d_inode(dentry));
+	} else
+		update_ctime(inode);
+out_unlock:
+	up_write(&REISERFS_I(inode)->i_xattr_sem);
+	dput(dentry);
+	return err;
+}
+
+/* We need to start a transaction to maintain lock ordering */
+int reiserfs_xattr_set(struct inode *inode, const char *name,
+		       const void *buffer, size_t buffer_size, int flags)
+{
+
+	struct reiserfs_transaction_handle th;
+	int error, error2;
+	size_t jbegin_count = reiserfs_xattr_nblocks(inode, buffer_size);
+
+	/* Check before we start a transaction and then do nothing. */
+	if (!d_really_is_positive(REISERFS_SB(inode->i_sb)->priv_root))
+		return -EOPNOTSUPP;
+
+	if (!(flags & XATTR_REPLACE))
+		jbegin_count += reiserfs_xattr_jcreate_nblocks(inode);
+
+	reiserfs_write_lock(inode->i_sb);
+	error = journal_begin(&th, inode->i_sb, jbegin_count);
+	reiserfs_write_unlock(inode->i_sb);
+	if (error) {
+		return error;
+	}
+
+	error = reiserfs_xattr_set_handle(&th, inode, name,
+					  buffer, buffer_size, flags);
+
+	reiserfs_write_lock(inode->i_sb);
+	error2 = journal_end(&th);
+	reiserfs_write_unlock(inode->i_sb);
+	if (error == 0)
+		error = error2;
+
+	return error;
+}
+
+/*
+ * inode->i_mutex: down
+ */
+int
+reiserfs_xattr_get(struct inode *inode, const char *name, void *buffer,
+		   size_t buffer_size)
+{
+	ssize_t err = 0;
+	struct dentry *dentry;
+	size_t isize;
+	size_t file_pos = 0;
+	size_t buffer_pos = 0;
+	struct page *page;
+	__u32 hash = 0;
+
+	if (name == NULL)
+		return -EINVAL;
+
+	/*
+	 * We can't have xattrs attached to v1 items since they don't have
+	 * generation numbers
+	 */
+	if (get_inode_sd_version(inode) == STAT_DATA_V1)
+		return -EOPNOTSUPP;
+
+	/*
+	 * priv_root needn't be initialized during mount so allow initial
+	 * lookups to succeed.
+	 */
+	if (!REISERFS_SB(inode->i_sb)->priv_root)
+		return 0;
+
+	dentry = xattr_lookup(inode, name, XATTR_REPLACE);
+	if (IS_ERR(dentry)) {
+		err = PTR_ERR(dentry);
+		goto out;
+	}
+
+	down_read(&REISERFS_I(inode)->i_xattr_sem);
+
+	isize = i_size_read(d_inode(dentry));
+
+	/* Just return the size needed */
+	if (buffer == NULL) {
+		err = isize - sizeof(struct reiserfs_xattr_header);
+		goto out_unlock;
+	}
+
+	if (buffer_size < isize - sizeof(struct reiserfs_xattr_header)) {
+		err = -ERANGE;
+		goto out_unlock;
+	}
+
+	while (file_pos < isize) {
+		size_t chunk;
+		char *data;
+		size_t skip = 0;
+
+		if (isize - file_pos > PAGE_SIZE)
+			chunk = PAGE_SIZE;
+		else
+			chunk = isize - file_pos;
+
+		page = reiserfs_get_page(d_inode(dentry), file_pos);
+		if (IS_ERR(page)) {
+			err = PTR_ERR(page);
+			goto out_unlock;
+		}
+
+		lock_page(page);
+		data = page_address(page);
+		if (file_pos == 0) {
+			struct reiserfs_xattr_header *rxh =
+			    (struct reiserfs_xattr_header *)data;
+			skip = file_pos = sizeof(struct reiserfs_xattr_header);
+			chunk -= skip;
+			/* Magic doesn't match up.. */
+			if (rxh->h_magic != cpu_to_le32(REISERFS_XATTR_MAGIC)) {
+				unlock_page(page);
+				reiserfs_put_page(page);
+				reiserfs_warning(inode->i_sb, "jdm-20001",
+						 "Invalid magic for xattr (%s) "
+						 "associated with %k", name,
+						 INODE_PKEY(inode));
+				err = -EIO;
+				goto out_unlock;
+			}
+			hash = le32_to_cpu(rxh->h_hash);
+		}
+		memcpy(buffer + buffer_pos, data + skip, chunk);
+		unlock_page(page);
+		reiserfs_put_page(page);
+		file_pos += chunk;
+		buffer_pos += chunk;
+		skip = 0;
+	}
+	err = isize - sizeof(struct reiserfs_xattr_header);
+
+	if (xattr_hash(buffer, isize - sizeof(struct reiserfs_xattr_header)) !=
+	    hash) {
+		reiserfs_warning(inode->i_sb, "jdm-20002",
+				 "Invalid hash for xattr (%s) associated "
+				 "with %k", name, INODE_PKEY(inode));
+		err = -EIO;
+	}
+
+out_unlock:
+	up_read(&REISERFS_I(inode)->i_xattr_sem);
+	dput(dentry);
+
+out:
+	return err;
+}
+
+/*
+ * In order to implement different sets of xattr operations for each xattr
+ * prefix with the generic xattr API, a filesystem should create a
+ * null-terminated array of struct xattr_handler (one for each prefix) and
+ * hang a pointer to it off of the s_xattr field of the superblock.
+ *
+ * The generic_fooxattr() functions will use this list to dispatch xattr
+ * operations to the correct xattr_handler.
+ */
+#define for_each_xattr_handler(handlers, handler)		\
+		for ((handler) = *(handlers)++;			\
+			(handler) != NULL;			\
+			(handler) = *(handlers)++)
+
+/* This is the implementation for the xattr plugin infrastructure */
+static inline const struct xattr_handler *
+find_xattr_handler_prefix(const struct xattr_handler **handlers,
+			   const char *name)
+{
+	const struct xattr_handler *xah;
+
+	if (!handlers)
+		return NULL;
+
+	for_each_xattr_handler(handlers, xah) {
+		const char *prefix = xattr_prefix(xah);
+		if (strncmp(prefix, name, strlen(prefix)) == 0)
+			break;
+	}
+
+	return xah;
+}
+
+struct listxattr_buf {
+	struct dir_context ctx;
+	size_t size;
+	size_t pos;
+	char *buf;
+	struct dentry *dentry;
+};
+
+static bool listxattr_filler(struct dir_context *ctx, const char *name,
+			    int namelen, loff_t offset, u64 ino,
+			    unsigned int d_type)
+{
+	struct listxattr_buf *b =
+		container_of(ctx, struct listxattr_buf, ctx);
+	size_t size;
+
+	if (name[0] != '.' ||
+	    (namelen != 1 && (name[1] != '.' || namelen != 2))) {
+		const struct xattr_handler *handler;
+
+		handler = find_xattr_handler_prefix(b->dentry->d_sb->s_xattr,
+						    name);
+		if (!handler /* Unsupported xattr name */ ||
+		    (handler->list && !handler->list(b->dentry)))
+			return true;
+		size = namelen + 1;
+		if (b->buf) {
+			if (b->pos + size > b->size) {
+				b->pos = -ERANGE;
+				return false;
+			}
+			memcpy(b->buf + b->pos, name, namelen);
+			b->buf[b->pos + namelen] = 0;
+		}
+		b->pos += size;
+	}
+	return true;
+}
+
+/*
+ * Inode operation listxattr()
+ *
+ * We totally ignore the generic listxattr here because it would be stupid
+ * not to. Since the xattrs are organized in a directory, we can just
+ * readdir to find them.
+ */
+ssize_t reiserfs_listxattr(struct dentry * dentry, char *buffer, size_t size)
+{
+	struct dentry *dir;
+	int err = 0;
+	struct listxattr_buf buf = {
+		.ctx.actor = listxattr_filler,
+		.dentry = dentry,
+		.buf = buffer,
+		.size = buffer ? size : 0,
+	};
+
+	if (d_really_is_negative(dentry))
+		return -EINVAL;
+
+	if (get_inode_sd_version(d_inode(dentry)) == STAT_DATA_V1)
+		return -EOPNOTSUPP;
+
+	dir = open_xa_dir(d_inode(dentry), XATTR_REPLACE);
+	if (IS_ERR(dir)) {
+		err = PTR_ERR(dir);
+		if (err == -ENODATA)
+			err = 0;  /* Not an error if there aren't any xattrs */
+		goto out;
+	}
+
+	inode_lock_nested(d_inode(dir), I_MUTEX_XATTR);
+	err = reiserfs_readdir_inode(d_inode(dir), &buf.ctx);
+	inode_unlock(d_inode(dir));
+
+	if (!err)
+		err = buf.pos;
+
+	dput(dir);
+out:
+	return err;
+}
+
+static int create_privroot(struct dentry *dentry)
+{
+	int err;
+	struct inode *inode = d_inode(dentry->d_parent);
+
+	WARN_ON_ONCE(!inode_is_locked(inode));
+
+	err = xattr_mkdir(inode, dentry, 0700);
+	if (err || d_really_is_negative(dentry)) {
+		reiserfs_warning(dentry->d_sb, "jdm-20006",
+				 "xattrs/ACLs enabled and couldn't "
+				 "find/create .reiserfs_priv. "
+				 "Failing mount.");
+		return -EOPNOTSUPP;
+	}
+
+	d_inode(dentry)->i_flags |= S_PRIVATE;
+	d_inode(dentry)->i_opflags &= ~IOP_XATTR;
+	reiserfs_info(dentry->d_sb, "Created %s - reserved for xattr "
+		      "storage.\n", PRIVROOT_NAME);
+
+	return 0;
+}
+
+#else
+int __init reiserfs_xattr_register_handlers(void) { return 0; }
+void reiserfs_xattr_unregister_handlers(void) {}
+static int create_privroot(struct dentry *dentry) { return 0; }
+#endif
+
+/* Actual operations that are exported to VFS-land */
+const struct xattr_handler *reiserfs_xattr_handlers[] = {
+#ifdef CONFIG_REISERFS_FS_XATTR
+	&reiserfs_xattr_user_handler,
+	&reiserfs_xattr_trusted_handler,
+#endif
+#ifdef CONFIG_REISERFS_FS_SECURITY
+	&reiserfs_xattr_security_handler,
+#endif
+#ifdef CONFIG_REISERFS_FS_POSIX_ACL
+	&posix_acl_access_xattr_handler,
+	&posix_acl_default_xattr_handler,
+#endif
+	NULL
+};
+
+static int xattr_mount_check(struct super_block *s)
+{
+	/*
+	 * We need generation numbers to ensure that the oid mapping is correct
+	 * v3.5 filesystems don't have them.
+	 */
+	if (old_format_only(s)) {
+		if (reiserfs_xattrs_optional(s)) {
+			/*
+			 * Old format filesystem, but optional xattrs have
+			 * been enabled. Error out.
+			 */
+			reiserfs_warning(s, "jdm-2005",
+					 "xattrs/ACLs not supported "
+					 "on pre-v3.6 format filesystems. "
+					 "Failing mount.");
+			return -EOPNOTSUPP;
+		}
+	}
+
+	return 0;
+}
+
+int reiserfs_permission(struct user_namespace *mnt_userns, struct inode *inode,
+			int mask)
+{
+	/*
+	 * We don't do permission checks on the internal objects.
+	 * Permissions are determined by the "owning" object.
+	 */
+	if (IS_PRIVATE(inode))
+		return 0;
+
+	return generic_permission(&init_user_ns, inode, mask);
+}
+
+static int xattr_hide_revalidate(struct dentry *dentry, unsigned int flags)
+{
+	return -EPERM;
+}
+
+static const struct dentry_operations xattr_lookup_poison_ops = {
+	.d_revalidate = xattr_hide_revalidate,
+};
+
+int reiserfs_lookup_privroot(struct super_block *s)
+{
+	struct dentry *dentry;
+	int err = 0;
+
+	/* If we don't have the privroot located yet - go find it */
+	inode_lock(d_inode(s->s_root));
+	dentry = lookup_one_len(PRIVROOT_NAME, s->s_root,
+				strlen(PRIVROOT_NAME));
+	if (!IS_ERR(dentry)) {
+		REISERFS_SB(s)->priv_root = dentry;
+		d_set_d_op(dentry, &xattr_lookup_poison_ops);
+		if (d_really_is_positive(dentry)) {
+			d_inode(dentry)->i_flags |= S_PRIVATE;
+			d_inode(dentry)->i_opflags &= ~IOP_XATTR;
+		}
+	} else
+		err = PTR_ERR(dentry);
+	inode_unlock(d_inode(s->s_root));
+
+	return err;
+}
+
+/*
+ * We need to take a copy of the mount flags since things like
+ * SB_RDONLY don't get set until *after* we're called.
+ * mount_flags != mount_options
+ */
+int reiserfs_xattr_init(struct super_block *s, int mount_flags)
+{
+	int err = 0;
+	struct dentry *privroot = REISERFS_SB(s)->priv_root;
+
+	err = xattr_mount_check(s);
+	if (err)
+		goto error;
+
+	if (d_really_is_negative(privroot) && !(mount_flags & SB_RDONLY)) {
+		inode_lock(d_inode(s->s_root));
+		err = create_privroot(REISERFS_SB(s)->priv_root);
+		inode_unlock(d_inode(s->s_root));
+	}
+
+	if (d_really_is_positive(privroot)) {
+		inode_lock(d_inode(privroot));
+		if (!REISERFS_SB(s)->xattr_root) {
+			struct dentry *dentry;
+
+			dentry = lookup_one_len(XAROOT_NAME, privroot,
+						strlen(XAROOT_NAME));
+			if (!IS_ERR(dentry))
+				REISERFS_SB(s)->xattr_root = dentry;
+			else
+				err = PTR_ERR(dentry);
+		}
+		inode_unlock(d_inode(privroot));
+	}
+
+error:
+	if (err) {
+		clear_bit(REISERFS_XATTRS_USER, &REISERFS_SB(s)->s_mount_opt);
+		clear_bit(REISERFS_POSIXACL, &REISERFS_SB(s)->s_mount_opt);
+	}
+
+	/* The super_block SB_POSIXACL must mirror the (no)acl mount option. */
+	if (reiserfs_posixacl(s))
+		s->s_flags |= SB_POSIXACL;
+	else
+		s->s_flags &= ~SB_POSIXACL;
+
+	return err;
+}