![Jan Kara](/assets/img/avatar_default.png)
Forbid user from changing file flags on quota files. User has no bussiness in playing with these flags when quota is on. Furthermore there is a remote possibility of deadlock due to a lock inversion between quota file's i_mutex and transaction's start (i_mutex for quota file is locked only when trasaction is started in quota operations) in ext3 and ext4. Signed-off-by: Jan Kara <jack@suse.cz> Cc: LIOU Payphone <lioupayphone@gmail.com> Cc: <linux-ext4@vger.kernel.org> Acked-by: Dave Kleikamp <shaggy@austin.ibm.com> Cc: <reiserfs-dev@namesys.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
203 lines
5.1 KiB
C
203 lines
5.1 KiB
C
/*
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* Copyright 2000 by Hans Reiser, licensing governed by reiserfs/README
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*/
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#include <linux/capability.h>
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#include <linux/fs.h>
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#include <linux/reiserfs_fs.h>
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#include <linux/time.h>
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#include <asm/uaccess.h>
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#include <linux/pagemap.h>
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#include <linux/smp_lock.h>
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#include <linux/compat.h>
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static int reiserfs_unpack(struct inode *inode, struct file *filp);
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/*
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** reiserfs_ioctl - handler for ioctl for inode
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** supported commands:
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** 1) REISERFS_IOC_UNPACK - try to unpack tail from direct item into indirect
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** and prevent packing file (argument arg has to be non-zero)
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** 2) REISERFS_IOC_[GS]ETFLAGS, REISERFS_IOC_[GS]ETVERSION
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** 3) That's all for a while ...
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*/
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int reiserfs_ioctl(struct inode *inode, struct file *filp, unsigned int cmd,
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unsigned long arg)
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{
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unsigned int flags;
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switch (cmd) {
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case REISERFS_IOC_UNPACK:
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if (S_ISREG(inode->i_mode)) {
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if (arg)
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return reiserfs_unpack(inode, filp);
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else
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return 0;
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} else
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return -ENOTTY;
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/* following two cases are taken from fs/ext2/ioctl.c by Remy
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Card (card@masi.ibp.fr) */
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case REISERFS_IOC_GETFLAGS:
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if (!reiserfs_attrs(inode->i_sb))
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return -ENOTTY;
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flags = REISERFS_I(inode)->i_attrs;
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i_attrs_to_sd_attrs(inode, (__u16 *) & flags);
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return put_user(flags, (int __user *)arg);
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case REISERFS_IOC_SETFLAGS:{
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if (!reiserfs_attrs(inode->i_sb))
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return -ENOTTY;
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if (IS_RDONLY(inode))
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return -EROFS;
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if (!is_owner_or_cap(inode))
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return -EPERM;
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if (get_user(flags, (int __user *)arg))
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return -EFAULT;
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/* Is it quota file? Do not allow user to mess with it. */
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if (IS_NOQUOTA(inode))
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return -EPERM;
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if (((flags ^ REISERFS_I(inode)->
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i_attrs) & (REISERFS_IMMUTABLE_FL |
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REISERFS_APPEND_FL))
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&& !capable(CAP_LINUX_IMMUTABLE))
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return -EPERM;
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if ((flags & REISERFS_NOTAIL_FL) &&
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S_ISREG(inode->i_mode)) {
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int result;
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result = reiserfs_unpack(inode, filp);
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if (result)
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return result;
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}
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sd_attrs_to_i_attrs(flags, inode);
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REISERFS_I(inode)->i_attrs = flags;
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inode->i_ctime = CURRENT_TIME_SEC;
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mark_inode_dirty(inode);
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return 0;
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}
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case REISERFS_IOC_GETVERSION:
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return put_user(inode->i_generation, (int __user *)arg);
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case REISERFS_IOC_SETVERSION:
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if (!is_owner_or_cap(inode))
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return -EPERM;
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if (IS_RDONLY(inode))
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return -EROFS;
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if (get_user(inode->i_generation, (int __user *)arg))
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return -EFAULT;
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inode->i_ctime = CURRENT_TIME_SEC;
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mark_inode_dirty(inode);
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return 0;
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default:
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return -ENOTTY;
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}
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}
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#ifdef CONFIG_COMPAT
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long reiserfs_compat_ioctl(struct file *file, unsigned int cmd,
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unsigned long arg)
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{
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struct inode *inode = file->f_path.dentry->d_inode;
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int ret;
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/* These are just misnamed, they actually get/put from/to user an int */
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switch (cmd) {
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case REISERFS_IOC32_UNPACK:
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cmd = REISERFS_IOC_UNPACK;
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break;
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case REISERFS_IOC32_GETFLAGS:
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cmd = REISERFS_IOC_GETFLAGS;
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break;
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case REISERFS_IOC32_SETFLAGS:
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cmd = REISERFS_IOC_SETFLAGS;
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break;
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case REISERFS_IOC32_GETVERSION:
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cmd = REISERFS_IOC_GETVERSION;
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break;
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case REISERFS_IOC32_SETVERSION:
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cmd = REISERFS_IOC_SETVERSION;
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break;
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default:
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return -ENOIOCTLCMD;
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}
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lock_kernel();
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ret = reiserfs_ioctl(inode, file, cmd, (unsigned long) compat_ptr(arg));
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unlock_kernel();
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return ret;
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}
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#endif
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int reiserfs_commit_write(struct file *f, struct page *page,
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unsigned from, unsigned to);
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int reiserfs_prepare_write(struct file *f, struct page *page,
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unsigned from, unsigned to);
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/*
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** reiserfs_unpack
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** Function try to convert tail from direct item into indirect.
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** It set up nopack attribute in the REISERFS_I(inode)->nopack
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*/
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static int reiserfs_unpack(struct inode *inode, struct file *filp)
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{
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int retval = 0;
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int index;
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struct page *page;
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struct address_space *mapping;
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unsigned long write_from;
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unsigned long blocksize = inode->i_sb->s_blocksize;
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if (inode->i_size == 0) {
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REISERFS_I(inode)->i_flags |= i_nopack_mask;
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return 0;
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}
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/* ioctl already done */
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if (REISERFS_I(inode)->i_flags & i_nopack_mask) {
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return 0;
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}
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/* we need to make sure nobody is changing the file size beneath
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** us
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*/
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mutex_lock(&inode->i_mutex);
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reiserfs_write_lock(inode->i_sb);
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write_from = inode->i_size & (blocksize - 1);
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/* if we are on a block boundary, we are already unpacked. */
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if (write_from == 0) {
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REISERFS_I(inode)->i_flags |= i_nopack_mask;
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goto out;
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}
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/* we unpack by finding the page with the tail, and calling
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** reiserfs_prepare_write on that page. This will force a
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** reiserfs_get_block to unpack the tail for us.
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*/
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index = inode->i_size >> PAGE_CACHE_SHIFT;
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mapping = inode->i_mapping;
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page = grab_cache_page(mapping, index);
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retval = -ENOMEM;
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if (!page) {
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goto out;
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}
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retval = reiserfs_prepare_write(NULL, page, write_from, write_from);
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if (retval)
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goto out_unlock;
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/* conversion can change page contents, must flush */
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flush_dcache_page(page);
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retval = reiserfs_commit_write(NULL, page, write_from, write_from);
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REISERFS_I(inode)->i_flags |= i_nopack_mask;
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out_unlock:
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unlock_page(page);
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page_cache_release(page);
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out:
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mutex_unlock(&inode->i_mutex);
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reiserfs_write_unlock(inode->i_sb);
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return retval;
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}
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