1028 lines
25 KiB
C
1028 lines
25 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* linux/fs/reiserfs/xattr.c
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*
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* Copyright (c) 2002 by Jeff Mahoney, <jeffm@suse.com>
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*
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*/
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/*
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* In order to implement EA/ACLs in a clean, backwards compatible manner,
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* they are implemented as files in a "private" directory.
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* Each EA is in it's own file, with the directory layout like so (/ is assumed
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* to be relative to fs root). Inside the /.reiserfs_priv/xattrs directory,
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* directories named using the capital-hex form of the objectid and
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* generation number are used. Inside each directory are individual files
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* named with the name of the extended attribute.
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*
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* So, for objectid 12648430, we could have:
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* /.reiserfs_priv/xattrs/C0FFEE.0/system.posix_acl_access
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* /.reiserfs_priv/xattrs/C0FFEE.0/system.posix_acl_default
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* /.reiserfs_priv/xattrs/C0FFEE.0/user.Content-Type
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* .. or similar.
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*
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* The file contents are the text of the EA. The size is known based on the
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* stat data describing the file.
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*
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* In the case of system.posix_acl_access and system.posix_acl_default, since
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* these are special cases for filesystem ACLs, they are interpreted by the
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* kernel, in addition, they are negatively and positively cached and attached
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* to the inode so that unnecessary lookups are avoided.
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*
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* Locking works like so:
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* Directory components (xattr root, xattr dir) are protectd by their i_mutex.
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* The xattrs themselves are protected by the xattr_sem.
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*/
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#include "reiserfs.h"
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#include <linux/capability.h>
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#include <linux/dcache.h>
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#include <linux/namei.h>
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#include <linux/errno.h>
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#include <linux/gfp.h>
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#include <linux/fs.h>
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#include <linux/file.h>
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#include <linux/pagemap.h>
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#include <linux/xattr.h>
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#include "xattr.h"
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#include "acl.h"
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#include <linux/uaccess.h>
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#include <net/checksum.h>
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#include <linux/stat.h>
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#include <linux/quotaops.h>
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#include <linux/security.h>
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#include <linux/posix_acl_xattr.h>
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#define PRIVROOT_NAME ".reiserfs_priv"
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#define XAROOT_NAME "xattrs"
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/*
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* Helpers for inode ops. We do this so that we don't have all the VFS
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* overhead and also for proper i_mutex annotation.
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* dir->i_mutex must be held for all of them.
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*/
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#ifdef CONFIG_REISERFS_FS_XATTR
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static int xattr_create(struct inode *dir, struct dentry *dentry, int mode)
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{
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BUG_ON(!inode_is_locked(dir));
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return dir->i_op->create(dir, dentry, mode, true);
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}
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#endif
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static int xattr_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
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{
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BUG_ON(!inode_is_locked(dir));
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return dir->i_op->mkdir(dir, dentry, mode);
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}
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/*
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* We use I_MUTEX_CHILD here to silence lockdep. It's safe because xattr
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* mutation ops aren't called during rename or splace, which are the
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* only other users of I_MUTEX_CHILD. It violates the ordering, but that's
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* better than allocating another subclass just for this code.
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*/
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static int xattr_unlink(struct inode *dir, struct dentry *dentry)
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{
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int error;
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BUG_ON(!inode_is_locked(dir));
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inode_lock_nested(d_inode(dentry), I_MUTEX_CHILD);
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error = dir->i_op->unlink(dir, dentry);
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inode_unlock(d_inode(dentry));
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if (!error)
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d_delete(dentry);
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return error;
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}
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static int xattr_rmdir(struct inode *dir, struct dentry *dentry)
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{
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int error;
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BUG_ON(!inode_is_locked(dir));
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inode_lock_nested(d_inode(dentry), I_MUTEX_CHILD);
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error = dir->i_op->rmdir(dir, dentry);
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if (!error)
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d_inode(dentry)->i_flags |= S_DEAD;
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inode_unlock(d_inode(dentry));
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if (!error)
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d_delete(dentry);
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return error;
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}
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#define xattr_may_create(flags) (!flags || flags & XATTR_CREATE)
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static struct dentry *open_xa_root(struct super_block *sb, int flags)
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{
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struct dentry *privroot = REISERFS_SB(sb)->priv_root;
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struct dentry *xaroot;
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if (d_really_is_negative(privroot))
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return ERR_PTR(-ENODATA);
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inode_lock_nested(d_inode(privroot), I_MUTEX_XATTR);
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xaroot = dget(REISERFS_SB(sb)->xattr_root);
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if (!xaroot)
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xaroot = ERR_PTR(-ENODATA);
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else if (d_really_is_negative(xaroot)) {
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int err = -ENODATA;
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if (xattr_may_create(flags))
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err = xattr_mkdir(d_inode(privroot), xaroot, 0700);
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if (err) {
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dput(xaroot);
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xaroot = ERR_PTR(err);
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}
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}
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inode_unlock(d_inode(privroot));
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return xaroot;
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}
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static struct dentry *open_xa_dir(const struct inode *inode, int flags)
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{
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struct dentry *xaroot, *xadir;
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char namebuf[17];
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xaroot = open_xa_root(inode->i_sb, flags);
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if (IS_ERR(xaroot))
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return xaroot;
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snprintf(namebuf, sizeof(namebuf), "%X.%X",
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le32_to_cpu(INODE_PKEY(inode)->k_objectid),
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inode->i_generation);
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inode_lock_nested(d_inode(xaroot), I_MUTEX_XATTR);
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xadir = lookup_one_len(namebuf, xaroot, strlen(namebuf));
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if (!IS_ERR(xadir) && d_really_is_negative(xadir)) {
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int err = -ENODATA;
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if (xattr_may_create(flags))
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err = xattr_mkdir(d_inode(xaroot), xadir, 0700);
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if (err) {
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dput(xadir);
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xadir = ERR_PTR(err);
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}
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}
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inode_unlock(d_inode(xaroot));
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dput(xaroot);
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return xadir;
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}
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/*
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* The following are side effects of other operations that aren't explicitly
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* modifying extended attributes. This includes operations such as permissions
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* or ownership changes, object deletions, etc.
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*/
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struct reiserfs_dentry_buf {
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struct dir_context ctx;
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struct dentry *xadir;
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int count;
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int err;
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struct dentry *dentries[8];
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};
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static int
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fill_with_dentries(struct dir_context *ctx, const char *name, int namelen,
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loff_t offset, u64 ino, unsigned int d_type)
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{
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struct reiserfs_dentry_buf *dbuf =
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container_of(ctx, struct reiserfs_dentry_buf, ctx);
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struct dentry *dentry;
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WARN_ON_ONCE(!inode_is_locked(d_inode(dbuf->xadir)));
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if (dbuf->count == ARRAY_SIZE(dbuf->dentries))
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return -ENOSPC;
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if (name[0] == '.' && (namelen < 2 ||
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(namelen == 2 && name[1] == '.')))
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return 0;
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dentry = lookup_one_len(name, dbuf->xadir, namelen);
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if (IS_ERR(dentry)) {
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dbuf->err = PTR_ERR(dentry);
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return PTR_ERR(dentry);
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} else if (d_really_is_negative(dentry)) {
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/* A directory entry exists, but no file? */
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reiserfs_error(dentry->d_sb, "xattr-20003",
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"Corrupted directory: xattr %pd listed but "
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"not found for file %pd.\n",
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dentry, dbuf->xadir);
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dput(dentry);
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dbuf->err = -EIO;
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return -EIO;
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}
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dbuf->dentries[dbuf->count++] = dentry;
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return 0;
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}
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static void
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cleanup_dentry_buf(struct reiserfs_dentry_buf *buf)
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{
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int i;
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for (i = 0; i < buf->count; i++)
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if (buf->dentries[i])
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dput(buf->dentries[i]);
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}
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static int reiserfs_for_each_xattr(struct inode *inode,
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int (*action)(struct dentry *, void *),
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void *data)
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{
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struct dentry *dir;
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int i, err = 0;
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struct reiserfs_dentry_buf buf = {
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.ctx.actor = fill_with_dentries,
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};
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/* Skip out, an xattr has no xattrs associated with it */
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if (IS_PRIVATE(inode) || get_inode_sd_version(inode) == STAT_DATA_V1)
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return 0;
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dir = open_xa_dir(inode, XATTR_REPLACE);
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if (IS_ERR(dir)) {
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err = PTR_ERR(dir);
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goto out;
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} else if (d_really_is_negative(dir)) {
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err = 0;
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goto out_dir;
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}
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inode_lock_nested(d_inode(dir), I_MUTEX_XATTR);
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buf.xadir = dir;
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while (1) {
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err = reiserfs_readdir_inode(d_inode(dir), &buf.ctx);
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if (err)
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break;
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if (buf.err) {
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err = buf.err;
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break;
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}
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if (!buf.count)
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break;
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for (i = 0; !err && i < buf.count && buf.dentries[i]; i++) {
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struct dentry *dentry = buf.dentries[i];
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if (!d_is_dir(dentry))
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err = action(dentry, data);
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dput(dentry);
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buf.dentries[i] = NULL;
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}
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if (err)
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break;
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buf.count = 0;
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}
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inode_unlock(d_inode(dir));
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cleanup_dentry_buf(&buf);
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if (!err) {
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/*
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* We start a transaction here to avoid a ABBA situation
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* between the xattr root's i_mutex and the journal lock.
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* This doesn't incur much additional overhead since the
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* new transaction will just nest inside the
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* outer transaction.
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*/
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int blocks = JOURNAL_PER_BALANCE_CNT * 2 + 2 +
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4 * REISERFS_QUOTA_TRANS_BLOCKS(inode->i_sb);
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struct reiserfs_transaction_handle th;
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reiserfs_write_lock(inode->i_sb);
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err = journal_begin(&th, inode->i_sb, blocks);
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reiserfs_write_unlock(inode->i_sb);
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if (!err) {
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int jerror;
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inode_lock_nested(d_inode(dir->d_parent),
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I_MUTEX_XATTR);
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err = action(dir, data);
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reiserfs_write_lock(inode->i_sb);
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jerror = journal_end(&th);
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reiserfs_write_unlock(inode->i_sb);
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inode_unlock(d_inode(dir->d_parent));
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err = jerror ?: err;
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}
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}
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out_dir:
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dput(dir);
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out:
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/* -ENODATA isn't an error */
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if (err == -ENODATA)
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err = 0;
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return err;
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}
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static int delete_one_xattr(struct dentry *dentry, void *data)
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{
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struct inode *dir = d_inode(dentry->d_parent);
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/* This is the xattr dir, handle specially. */
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if (d_is_dir(dentry))
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return xattr_rmdir(dir, dentry);
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return xattr_unlink(dir, dentry);
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}
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static int chown_one_xattr(struct dentry *dentry, void *data)
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{
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struct iattr *attrs = data;
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int ia_valid = attrs->ia_valid;
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int err;
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/*
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* We only want the ownership bits. Otherwise, we'll do
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* things like change a directory to a regular file if
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* ATTR_MODE is set.
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*/
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attrs->ia_valid &= (ATTR_UID|ATTR_GID);
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err = reiserfs_setattr(dentry, attrs);
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attrs->ia_valid = ia_valid;
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return err;
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}
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/* No i_mutex, but the inode is unconnected. */
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int reiserfs_delete_xattrs(struct inode *inode)
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{
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int err = reiserfs_for_each_xattr(inode, delete_one_xattr, NULL);
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|
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if (err)
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reiserfs_warning(inode->i_sb, "jdm-20004",
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"Couldn't delete all xattrs (%d)\n", err);
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return err;
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}
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|
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/* inode->i_mutex: down */
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int reiserfs_chown_xattrs(struct inode *inode, struct iattr *attrs)
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{
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int err = reiserfs_for_each_xattr(inode, chown_one_xattr, attrs);
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|
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if (err)
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reiserfs_warning(inode->i_sb, "jdm-20007",
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"Couldn't chown all xattrs (%d)\n", err);
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return err;
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}
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#ifdef CONFIG_REISERFS_FS_XATTR
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/*
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* Returns a dentry corresponding to a specific extended attribute file
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* for the inode. If flags allow, the file is created. Otherwise, a
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* valid or negative dentry, or an error is returned.
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*/
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static struct dentry *xattr_lookup(struct inode *inode, const char *name,
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int flags)
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{
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struct dentry *xadir, *xafile;
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int err = 0;
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xadir = open_xa_dir(inode, flags);
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if (IS_ERR(xadir))
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return ERR_CAST(xadir);
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inode_lock_nested(d_inode(xadir), I_MUTEX_XATTR);
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xafile = lookup_one_len(name, xadir, strlen(name));
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if (IS_ERR(xafile)) {
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err = PTR_ERR(xafile);
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goto out;
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}
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if (d_really_is_positive(xafile) && (flags & XATTR_CREATE))
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err = -EEXIST;
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|
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if (d_really_is_negative(xafile)) {
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err = -ENODATA;
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if (xattr_may_create(flags))
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err = xattr_create(d_inode(xadir), xafile,
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0700|S_IFREG);
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}
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|
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if (err)
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dput(xafile);
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out:
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inode_unlock(d_inode(xadir));
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dput(xadir);
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if (err)
|
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return ERR_PTR(err);
|
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return xafile;
|
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}
|
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|
|
/* Internal operations on file data */
|
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static inline void reiserfs_put_page(struct page *page)
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{
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kunmap(page);
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put_page(page);
|
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}
|
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|
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static struct page *reiserfs_get_page(struct inode *dir, size_t n)
|
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{
|
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struct address_space *mapping = dir->i_mapping;
|
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struct page *page;
|
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/*
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* We can deadlock if we try to free dentries,
|
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* and an unlink/rmdir has just occurred - GFP_NOFS avoids this
|
|
*/
|
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mapping_set_gfp_mask(mapping, GFP_NOFS);
|
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page = read_mapping_page(mapping, n >> PAGE_SHIFT, NULL);
|
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if (!IS_ERR(page)) {
|
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kmap(page);
|
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if (PageError(page))
|
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goto fail;
|
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}
|
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return page;
|
|
|
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fail:
|
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reiserfs_put_page(page);
|
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return ERR_PTR(-EIO);
|
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}
|
|
|
|
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
|
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* when trying to fetch xattrs. Treating the hash as __wsum_t would
|
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* lower the frequency of mismatch. This is an endianness bug in
|
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* 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.
|
|
*/
|
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return csum_partial(msg, len, 0);
|
|
}
|
|
|
|
int reiserfs_commit_write(struct file *f, struct page *page,
|
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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))
|
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return;
|
|
|
|
inode->i_ctime = current_time(inode);
|
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mark_inode_dirty(inode);
|
|
}
|
|
|
|
static int lookup_and_delete_xattr(struct inode *inode, const char *name)
|
|
{
|
|
int err = 0;
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struct dentry *dentry, *xadir;
|
|
|
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xadir = open_xa_dir(inode, XATTR_REPLACE);
|
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if (IS_ERR(xadir))
|
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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);
|
|
}
|
|
|
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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(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);
|
|
|
|
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;
|
|
|
|
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 int 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 0;
|
|
size = namelen + 1;
|
|
if (b->buf) {
|
|
if (b->pos + size > b->size) {
|
|
b->pos = -ERANGE;
|
|
return -ERANGE;
|
|
}
|
|
memcpy(b->buf + b->pos, name, namelen);
|
|
b->buf[b->pos + namelen] = 0;
|
|
}
|
|
b->pos += size;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* 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 (!dentry->d_sb->s_xattr ||
|
|
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;
|
|
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 */
|
|
static 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 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(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;
|
|
} 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)) {
|
|
s->s_xattr = reiserfs_xattr_handlers;
|
|
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;
|
|
}
|