e2b4657453
Calculate & store the max offset for bitmapped files, and catch too-large seeks, truncates, and writes in ext4, shortening or rejecting as appropriate. Signed-off-by: Eric Sandeen <sandeen@redhat.com>
156 lines
4.1 KiB
C
156 lines
4.1 KiB
C
/*
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* linux/fs/ext4/file.c
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*
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* Copyright (C) 1992, 1993, 1994, 1995
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* Remy Card (card@masi.ibp.fr)
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* Laboratoire MASI - Institut Blaise Pascal
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* Universite Pierre et Marie Curie (Paris VI)
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*
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* from
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*
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* linux/fs/minix/file.c
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*
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* Copyright (C) 1991, 1992 Linus Torvalds
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*
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* ext4 fs regular file handling primitives
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*
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* 64-bit file support on 64-bit platforms by Jakub Jelinek
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* (jj@sunsite.ms.mff.cuni.cz)
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*/
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#include <linux/time.h>
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#include <linux/fs.h>
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#include <linux/jbd2.h>
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#include <linux/ext4_fs.h>
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#include <linux/ext4_jbd2.h>
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#include "xattr.h"
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#include "acl.h"
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/*
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* Called when an inode is released. Note that this is different
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* from ext4_file_open: open gets called at every open, but release
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* gets called only when /all/ the files are closed.
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*/
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static int ext4_release_file (struct inode * inode, struct file * filp)
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{
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/* if we are the last writer on the inode, drop the block reservation */
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if ((filp->f_mode & FMODE_WRITE) &&
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(atomic_read(&inode->i_writecount) == 1))
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{
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down_write(&EXT4_I(inode)->i_data_sem);
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ext4_discard_reservation(inode);
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up_write(&EXT4_I(inode)->i_data_sem);
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}
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if (is_dx(inode) && filp->private_data)
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ext4_htree_free_dir_info(filp->private_data);
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return 0;
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}
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static ssize_t
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ext4_file_write(struct kiocb *iocb, const struct iovec *iov,
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unsigned long nr_segs, loff_t pos)
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{
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struct file *file = iocb->ki_filp;
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struct inode *inode = file->f_path.dentry->d_inode;
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ssize_t ret;
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int err;
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/*
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* If we have encountered a bitmap-format file, the size limit
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* is smaller than s_maxbytes, which is for extent-mapped files.
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*/
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if (!(EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL)) {
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struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
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size_t length = iov_length(iov, nr_segs);
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if (pos > sbi->s_bitmap_maxbytes)
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return -EFBIG;
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if (pos + length > sbi->s_bitmap_maxbytes) {
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nr_segs = iov_shorten((struct iovec *)iov, nr_segs,
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sbi->s_bitmap_maxbytes - pos);
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}
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}
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ret = generic_file_aio_write(iocb, iov, nr_segs, pos);
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/*
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* Skip flushing if there was an error, or if nothing was written.
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*/
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if (ret <= 0)
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return ret;
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/*
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* If the inode is IS_SYNC, or is O_SYNC and we are doing data
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* journalling then we need to make sure that we force the transaction
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* to disk to keep all metadata uptodate synchronously.
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*/
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if (file->f_flags & O_SYNC) {
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/*
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* If we are non-data-journaled, then the dirty data has
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* already been flushed to backing store by generic_osync_inode,
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* and the inode has been flushed too if there have been any
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* modifications other than mere timestamp updates.
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*
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* Open question --- do we care about flushing timestamps too
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* if the inode is IS_SYNC?
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*/
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if (!ext4_should_journal_data(inode))
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return ret;
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goto force_commit;
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}
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/*
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* So we know that there has been no forced data flush. If the inode
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* is marked IS_SYNC, we need to force one ourselves.
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*/
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if (!IS_SYNC(inode))
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return ret;
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/*
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* Open question #2 --- should we force data to disk here too? If we
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* don't, the only impact is that data=writeback filesystems won't
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* flush data to disk automatically on IS_SYNC, only metadata (but
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* historically, that is what ext2 has done.)
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*/
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force_commit:
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err = ext4_force_commit(inode->i_sb);
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if (err)
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return err;
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return ret;
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}
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const struct file_operations ext4_file_operations = {
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.llseek = generic_file_llseek,
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.read = do_sync_read,
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.write = do_sync_write,
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.aio_read = generic_file_aio_read,
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.aio_write = ext4_file_write,
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.ioctl = ext4_ioctl,
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#ifdef CONFIG_COMPAT
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.compat_ioctl = ext4_compat_ioctl,
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#endif
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.mmap = generic_file_mmap,
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.open = generic_file_open,
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.release = ext4_release_file,
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.fsync = ext4_sync_file,
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.splice_read = generic_file_splice_read,
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.splice_write = generic_file_splice_write,
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};
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const struct inode_operations ext4_file_inode_operations = {
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.truncate = ext4_truncate,
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.setattr = ext4_setattr,
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#ifdef CONFIG_EXT4DEV_FS_XATTR
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.setxattr = generic_setxattr,
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.getxattr = generic_getxattr,
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.listxattr = ext4_listxattr,
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.removexattr = generic_removexattr,
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#endif
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.permission = ext4_permission,
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.fallocate = ext4_fallocate,
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};
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