file.c 4.4 KB
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/*
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 *  linux/fs/ext4/file.c
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 *
 * Copyright (C) 1992, 1993, 1994, 1995
 * Remy Card (card@masi.ibp.fr)
 * Laboratoire MASI - Institut Blaise Pascal
 * Universite Pierre et Marie Curie (Paris VI)
 *
 *  from
 *
 *  linux/fs/minix/file.c
 *
 *  Copyright (C) 1991, 1992  Linus Torvalds
 *
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 *  ext4 fs regular file handling primitives
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 *
 *  64-bit file support on 64-bit platforms by Jakub Jelinek
 *	(jj@sunsite.ms.mff.cuni.cz)
 */

#include <linux/time.h>
#include <linux/fs.h>
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#include <linux/jbd2.h>
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#include <linux/mount.h>
#include <linux/path.h>
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#include <linux/quotaops.h>
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#include "ext4.h"
#include "ext4_jbd2.h"
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#include "xattr.h"
#include "acl.h"

/*
 * 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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static int ext4_release_file(struct inode *inode, struct file *filp)
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{
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	if (ext4_test_inode_state(inode, EXT4_STATE_DA_ALLOC_CLOSE)) {
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		ext4_alloc_da_blocks(inode);
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		ext4_clear_inode_state(inode, EXT4_STATE_DA_ALLOC_CLOSE);
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	}
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	/* if we are the last writer on the inode, drop the block reservation */
	if ((filp->f_mode & FMODE_WRITE) &&
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			(atomic_read(&inode->i_writecount) == 1) &&
		        !EXT4_I(inode)->i_reserved_data_blocks)
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	{
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		down_write(&EXT4_I(inode)->i_data_sem);
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		ext4_discard_preallocations(inode);
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		up_write(&EXT4_I(inode)->i_data_sem);
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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;
}

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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	struct inode *inode = iocb->ki_filp->f_path.dentry->d_inode;
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	/*
	 * If we have encountered a bitmap-format file, the size limit
	 * is smaller than s_maxbytes, which is for extent-mapped files.
	 */

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	if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))) {
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		struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
		size_t length = iov_length(iov, nr_segs);
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		if ((pos > sbi->s_bitmap_maxbytes ||
		    (pos == sbi->s_bitmap_maxbytes && length > 0)))
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			return -EFBIG;

		if (pos + length > sbi->s_bitmap_maxbytes) {
			nr_segs = iov_shorten((struct iovec *)iov, nr_segs,
					      sbi->s_bitmap_maxbytes - pos);
		}
	}

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	return generic_file_aio_write(iocb, iov, nr_segs, pos);
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}

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static const struct vm_operations_struct ext4_file_vm_ops = {
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	.fault		= filemap_fault,
	.page_mkwrite   = ext4_page_mkwrite,
};

static int ext4_file_mmap(struct file *file, struct vm_area_struct *vma)
{
	struct address_space *mapping = file->f_mapping;

	if (!mapping->a_ops->readpage)
		return -ENOEXEC;
	file_accessed(file);
	vma->vm_ops = &ext4_file_vm_ops;
	vma->vm_flags |= VM_CAN_NONLINEAR;
	return 0;
}

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static int ext4_file_open(struct inode * inode, struct file * filp)
{
	struct super_block *sb = inode->i_sb;
	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
	struct vfsmount *mnt = filp->f_path.mnt;
	struct path path;
	char buf[64], *cp;

	if (unlikely(!(sbi->s_mount_flags & EXT4_MF_MNTDIR_SAMPLED) &&
		     !(sb->s_flags & MS_RDONLY))) {
		sbi->s_mount_flags |= EXT4_MF_MNTDIR_SAMPLED;
		/*
		 * Sample where the filesystem has been mounted and
		 * store it in the superblock for sysadmin convenience
		 * when trying to sort through large numbers of block
		 * devices or filesystem images.
		 */
		memset(buf, 0, sizeof(buf));
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		path.mnt = mnt;
		path.dentry = mnt->mnt_root;
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		cp = d_path(&path, buf, sizeof(buf));
		if (!IS_ERR(cp)) {
			memcpy(sbi->s_es->s_last_mounted, cp,
			       sizeof(sbi->s_es->s_last_mounted));
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			ext4_mark_super_dirty(sb);
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		}
	}
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	return dquot_file_open(inode, filp);
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}

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const struct file_operations ext4_file_operations = {
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	.llseek		= generic_file_llseek,
	.read		= do_sync_read,
	.write		= do_sync_write,
	.aio_read	= generic_file_aio_read,
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	.aio_write	= ext4_file_write,
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	.unlocked_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		= ext4_file_mmap,
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	.open		= ext4_file_open,
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	.release	= ext4_release_file,
	.fsync		= ext4_sync_file,
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	.splice_read	= generic_file_splice_read,
	.splice_write	= generic_file_splice_write,
};

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const struct inode_operations ext4_file_inode_operations = {
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	.truncate	= ext4_truncate,
	.setattr	= ext4_setattr,
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	.getattr	= ext4_getattr,
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#ifdef CONFIG_EXT4_FS_XATTR
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	.setxattr	= generic_setxattr,
	.getxattr	= generic_getxattr,
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	.listxattr	= ext4_listxattr,
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	.removexattr	= generic_removexattr,
#endif
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	.check_acl	= ext4_check_acl,
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	.fallocate	= ext4_fallocate,
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	.fiemap		= ext4_fiemap,
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};