1/*
2 *  linux/fs/ext4/file.c
3 *
4 * Copyright (C) 1992, 1993, 1994, 1995
5 * Remy Card (card@masi.ibp.fr)
6 * Laboratoire MASI - Institut Blaise Pascal
7 * Universite Pierre et Marie Curie (Paris VI)
8 *
9 *  from
10 *
11 *  linux/fs/minix/file.c
12 *
13 *  Copyright (C) 1991, 1992  Linus Torvalds
14 *
15 *  ext4 fs regular file handling primitives
16 *
17 *  64-bit file support on 64-bit platforms by Jakub Jelinek
18 *	(jj@sunsite.ms.mff.cuni.cz)
19 */
20
21#include <linux/time.h>
22#include <linux/fs.h>
23#include <linux/jbd2.h>
24#include <linux/mount.h>
25#include <linux/path.h>
26#include <linux/quotaops.h>
27#include "ext4.h"
28#include "ext4_jbd2.h"
29#include "xattr.h"
30#include "acl.h"
31
32/*
33 * Called when an inode is released. Note that this is different
34 * from ext4_file_open: open gets called at every open, but release
35 * gets called only when /all/ the files are closed.
36 */
37static int ext4_release_file(struct inode *inode, struct file *filp)
38{
39	if (ext4_test_inode_state(inode, EXT4_STATE_DA_ALLOC_CLOSE)) {
40		ext4_alloc_da_blocks(inode);
41		ext4_clear_inode_state(inode, EXT4_STATE_DA_ALLOC_CLOSE);
42	}
43	/* if we are the last writer on the inode, drop the block reservation */
44	if ((filp->f_mode & FMODE_WRITE) &&
45			(atomic_read(&inode->i_writecount) == 1) &&
46		        !EXT4_I(inode)->i_reserved_data_blocks)
47	{
48		down_write(&EXT4_I(inode)->i_data_sem);
49		ext4_discard_preallocations(inode);
50		up_write(&EXT4_I(inode)->i_data_sem);
51	}
52	if (is_dx(inode) && filp->private_data)
53		ext4_htree_free_dir_info(filp->private_data);
54
55	return 0;
56}
57
58static ssize_t
59ext4_file_write(struct kiocb *iocb, const struct iovec *iov,
60		unsigned long nr_segs, loff_t pos)
61{
62	struct inode *inode = iocb->ki_filp->f_path.dentry->d_inode;
63
64	/*
65	 * If we have encountered a bitmap-format file, the size limit
66	 * is smaller than s_maxbytes, which is for extent-mapped files.
67	 */
68
69	if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))) {
70		struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
71		size_t length = iov_length(iov, nr_segs);
72
73		if ((pos > sbi->s_bitmap_maxbytes ||
74		    (pos == sbi->s_bitmap_maxbytes && length > 0)))
75			return -EFBIG;
76
77		if (pos + length > sbi->s_bitmap_maxbytes) {
78			nr_segs = iov_shorten((struct iovec *)iov, nr_segs,
79					      sbi->s_bitmap_maxbytes - pos);
80		}
81	}
82
83	return generic_file_aio_write(iocb, iov, nr_segs, pos);
84}
85
86static const struct vm_operations_struct ext4_file_vm_ops = {
87	.fault		= filemap_fault,
88	.page_mkwrite   = ext4_page_mkwrite,
89};
90
91static int ext4_file_mmap(struct file *file, struct vm_area_struct *vma)
92{
93	struct address_space *mapping = file->f_mapping;
94
95	if (!mapping->a_ops->readpage)
96		return -ENOEXEC;
97	file_accessed(file);
98	vma->vm_ops = &ext4_file_vm_ops;
99	vma->vm_flags |= VM_CAN_NONLINEAR;
100	return 0;
101}
102
103static int ext4_file_open(struct inode * inode, struct file * filp)
104{
105	struct super_block *sb = inode->i_sb;
106	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
107	struct vfsmount *mnt = filp->f_path.mnt;
108	struct path path;
109	char buf[64], *cp;
110
111	if (unlikely(!(sbi->s_mount_flags & EXT4_MF_MNTDIR_SAMPLED) &&
112		     !(sb->s_flags & MS_RDONLY))) {
113		sbi->s_mount_flags |= EXT4_MF_MNTDIR_SAMPLED;
114		/*
115		 * Sample where the filesystem has been mounted and
116		 * store it in the superblock for sysadmin convenience
117		 * when trying to sort through large numbers of block
118		 * devices or filesystem images.
119		 */
120		memset(buf, 0, sizeof(buf));
121		path.mnt = mnt;
122		path.dentry = mnt->mnt_root;
123		cp = d_path(&path, buf, sizeof(buf));
124		if (!IS_ERR(cp)) {
125			memcpy(sbi->s_es->s_last_mounted, cp,
126			       sizeof(sbi->s_es->s_last_mounted));
127			ext4_mark_super_dirty(sb);
128		}
129	}
130	return dquot_file_open(inode, filp);
131}
132
133const struct file_operations ext4_file_operations = {
134	.llseek		= generic_file_llseek,
135	.read		= do_sync_read,
136	.write		= do_sync_write,
137	.aio_read	= generic_file_aio_read,
138	.aio_write	= ext4_file_write,
139	.unlocked_ioctl = ext4_ioctl,
140#ifdef CONFIG_COMPAT
141	.compat_ioctl	= ext4_compat_ioctl,
142#endif
143	.mmap		= ext4_file_mmap,
144	.open		= ext4_file_open,
145	.release	= ext4_release_file,
146	.fsync		= ext4_sync_file,
147	.splice_read	= generic_file_splice_read,
148	.splice_write	= generic_file_splice_write,
149};
150
151const struct inode_operations ext4_file_inode_operations = {
152	.truncate	= ext4_truncate,
153	.setattr	= ext4_setattr,
154	.getattr	= ext4_getattr,
155#ifdef CONFIG_EXT4_FS_XATTR
156	.setxattr	= generic_setxattr,
157	.getxattr	= generic_getxattr,
158	.listxattr	= ext4_listxattr,
159	.removexattr	= generic_removexattr,
160#endif
161	.check_acl	= ext4_check_acl,
162	.fallocate	= ext4_fallocate,
163	.fiemap		= ext4_fiemap,
164};
165