C++ EXT4_I函数代码示例

/**
 * ext4_get_crypto_ctx() - Gets an encryption context
 * @inode:       The inode for which we are doing the crypto
 *
 * Allocates and initializes an encryption context.
 *
 * Return: An allocated and initialized encryption context on success; error
 * value or NULL otherwise.
 */
struct ext4_crypto_ctx *ext4_get_crypto_ctx(struct inode *inode)
{
	struct ext4_crypto_ctx *ctx = NULL;
	int res = 0;
	unsigned long flags;
	struct ext4_crypt_info *ci = EXT4_I(inode)->i_crypt_info;

	if (ci == NULL)
		return ERR_PTR(-ENOKEY);

	/*
	 * We first try getting the ctx from a free list because in
	 * the common case the ctx will have an allocated and
	 * initialized crypto tfm, so it's probably a worthwhile
	 * optimization. For the bounce page, we first try getting it
	 * from the kernel allocator because that's just about as fast
	 * as getting it from a list and because a cache of free pages
	 * should generally be a "last resort" option for a filesystem
	 * to be able to do its job.
	 */
	spin_lock_irqsave(&ext4_crypto_ctx_lock, flags);
	ctx = list_first_entry_or_null(&ext4_free_crypto_ctxs,
				       struct ext4_crypto_ctx, free_list);
	if (ctx)
		list_del(&ctx->free_list);
	spin_unlock_irqrestore(&ext4_crypto_ctx_lock, flags);
	if (!ctx) {
		ctx = kmem_cache_zalloc(ext4_crypto_ctx_cachep, GFP_NOFS);
		if (!ctx) {
			res = -ENOMEM;
			goto out;
		}
		ctx->flags |= EXT4_CTX_REQUIRES_FREE_ENCRYPT_FL;
	} else {
		ctx->flags &= ~EXT4_CTX_REQUIRES_FREE_ENCRYPT_FL;
	}
	ctx->flags &= ~EXT4_WRITE_PATH_FL;

out:
	if (res) {
		if (!IS_ERR_OR_NULL(ctx))
			ext4_release_crypto_ctx(ctx);
		ctx = ERR_PTR(res);
	}
	return ctx;
}

int ext4_sync_file(struct file *file, struct dentry *dentry, int datasync)
{
	struct inode *inode = dentry->d_inode;
	struct ext4_inode_info *ei = EXT4_I(inode);
	journal_t *journal = EXT4_SB(inode->i_sb)->s_journal;
	int ret;
	tid_t commit_tid;

	J_ASSERT(ext4_journal_current_handle() == NULL);

	trace_ext4_sync_file(file, dentry, datasync);

	if (inode->i_sb->s_flags & MS_RDONLY)
		return 0;

	ret = flush_aio_dio_completed_IO(inode);
	if (ret < 0)
		return ret;
	
	if (!journal)
		return simple_fsync(file, dentry, datasync);

	/*
	 * data=writeback,ordered:
	 *  The caller's filemap_fdatawrite()/wait will sync the data.
	 *  Metadata is in the journal, we wait for proper transaction to
	 *  commit here.
	 *
	 * data=journal:
	 *  filemap_fdatawrite won't do anything (the buffers are clean).
	 *  ext4_force_commit will write the file data into the journal and
	 *  will wait on that.
	 *  filemap_fdatawait() will encounter a ton of newly-dirtied pages
	 *  (they were dirtied by commit).  But that's OK - the blocks are
	 *  safe in-journal, which is all fsync() needs to ensure.
	 */
	if (ext4_should_journal_data(inode))
		return ext4_force_commit(inode->i_sb);

	commit_tid = datasync ? ei->i_datasync_tid : ei->i_sync_tid;
	if (jbd2_log_start_commit(journal, commit_tid))
		jbd2_log_wait_commit(journal, commit_tid);
	else if (journal->j_flags & JBD2_BARRIER)
		blkdev_issue_flush(inode->i_sb->s_bdev, NULL);
	return ret;
}

void ext4_free_io_end(ext4_io_end_t *io)
{
	int i;
	wait_queue_head_t *wq;

	BUG_ON(!io);
	if (io->page)
		put_page(io->page);
	for (i = 0; i < io->num_io_pages; i++)
		put_io_page(io->pages[i]);
	io->num_io_pages = 0;
	wq = to_ioend_wq(io->inode);
	if (atomic_dec_and_test(&EXT4_I(io->inode)->i_ioend_count) &&
	    waitqueue_active(wq))
		wake_up_all(wq);
	kmem_cache_free(io_end_cachep, io);
}

static int ext4_finish_convert_inline_dir(handle_t *handle,
					  struct inode *inode,
					  struct buffer_head *dir_block,
					  void *buf,
					  int inline_size)
{
	int err, csum_size = 0, header_size = 0;
	struct ext4_dir_entry_2 *de;
	struct ext4_dir_entry_tail *t;
	void *target = dir_block->b_data;

	/*
	 * First create "." and ".." and then copy the dir information
	 * back to the block.
	 */
	de = (struct ext4_dir_entry_2 *)target;
	de = ext4_init_dot_dotdot(inode, de,
		inode->i_sb->s_blocksize, csum_size,
		le32_to_cpu(((struct ext4_dir_entry_2 *)buf)->inode), 1);
	header_size = (void *)de - target;

	memcpy((void *)de, buf + EXT4_INLINE_DOTDOT_SIZE,
		inline_size - EXT4_INLINE_DOTDOT_SIZE);

	if (ext4_has_metadata_csum(inode->i_sb))
		csum_size = sizeof(struct ext4_dir_entry_tail);

	inode->i_size = inode->i_sb->s_blocksize;
	i_size_write(inode, inode->i_sb->s_blocksize);
	EXT4_I(inode)->i_disksize = inode->i_sb->s_blocksize;
	ext4_update_final_de(dir_block->b_data,
			inline_size - EXT4_INLINE_DOTDOT_SIZE + header_size,
			inode->i_sb->s_blocksize - csum_size);

	if (csum_size) {
		t = EXT4_DIRENT_TAIL(dir_block->b_data,
				     inode->i_sb->s_blocksize);
		initialize_dirent_tail(t, inode->i_sb->s_blocksize);
	}
	set_buffer_uptodate(dir_block);
	err = ext4_handle_dirty_dirent_node(handle, inode, dir_block);
	if (err)
		return err;
	set_buffer_verified(dir_block);
	return ext4_mark_inode_dirty(handle, inode);
}

/*
 * Validate dentries for encrypted directories to make sure we aren't
 * potentially caching stale data after a key has been added or
 * removed.
 */
static int ext4_d_revalidate(struct dentry *dentry, unsigned int flags)
{
	struct inode *dir = d_inode(dentry->d_parent);
	struct ext4_crypt_info *ci = EXT4_I(dir)->i_crypt_info;
	int dir_has_key, cached_with_key;

	if (!ext4_encrypted_inode(dir))
		return 0;

	if (ci && ci->ci_keyring_key &&
	    (ci->ci_keyring_key->flags & ((1 << KEY_FLAG_INVALIDATED) |
					  (1 << KEY_FLAG_REVOKED) |
					  (1 << KEY_FLAG_DEAD))))
		ci = NULL;

	/* this should eventually be an flag in d_flags */
	cached_with_key = dentry->d_fsdata != NULL;
	dir_has_key = (ci != NULL);

	/*
	 * If the dentry was cached without the key, and it is a
	 * negative dentry, it might be a valid name.  We can't check
	 * if the key has since been made available due to locking
	 * reasons, so we fail the validation so ext4_lookup() can do
	 * this check.
	 *
	 * We also fail the validation if the dentry was created with
	 * the key present, but we no longer have the key, or vice versa.
	 */
	if ((!cached_with_key && d_is_negative(dentry)) ||
	    (!cached_with_key && dir_has_key) ||
	    (cached_with_key && !dir_has_key)) {
#if 0				/* Revalidation debug */
		char buf[80];
		char *cp = simple_dname(dentry, buf, sizeof(buf));

		if (IS_ERR(cp))
			cp = (char *) "???";
		pr_err("revalidate: %s %p %d %d %d\n", cp, dentry->d_fsdata,
		       cached_with_key, d_is_negative(dentry),
		       dir_has_key);
#endif
		return 0;
	}
	return 1;
}

static void ext4_release_io_end(ext4_io_end_t *io_end)
{
	struct bio *bio, *next_bio;

	BUG_ON(!list_empty(&io_end->list));
	BUG_ON(io_end->flag & EXT4_IO_END_UNWRITTEN);
	WARN_ON(io_end->handle);

	if (atomic_dec_and_test(&EXT4_I(io_end->inode)->i_ioend_count))
		wake_up_all(ext4_ioend_wq(io_end->inode));

	for (bio = io_end->bio; bio; bio = next_bio) {
		next_bio = bio->bi_private;
		ext4_finish_bio(bio);
		bio_put(bio);
	}
	kmem_cache_free(io_end_cachep, io_end);
}

static void ext4_es_print_tree(struct inode *inode)
{
	struct ext4_es_tree *tree;
	struct rb_node *node;

	printk(KERN_DEBUG "status extents for inode %lu:", inode->i_ino);
	tree = &EXT4_I(inode)->i_es_tree;
	node = rb_first(&tree->root);
	while (node) {
		struct extent_status *es;
		es = rb_entry(node, struct extent_status, rb_node);
		printk(KERN_DEBUG " [%u/%u) %llu %x",
		       es->es_lblk, es->es_len,
		       ext4_es_pblock(es), ext4_es_status(es));
		node = rb_next(node);
	}
	printk(KERN_DEBUG "\n");
}

static unsigned long ext4_inode_by_name(struct inode *inode, struct qstr *unit)
{
	struct super_block *sb = inode->i_sb;
	struct ext4_sb_info *e4_sbi;
	struct ext4_inode_info *e4_ini = EXT4_I(inode);
	struct ext4_dir_entry_2 *e4_de;
	struct ext4_inode *parent = e4_ini->i_e4in;
	char buff[inode->i_sb->s_blocksize];
	size_t len = 0;
	int blocks, i;
	size_t block_size;

	e4_sbi = sb->s_fs_info;
	block_size = 1024 << e4_sbi->e4_sb.s_log_block_size;

	blocks = (parent->i_size_lo + block_size - 1) / block_size;
	__le32 block_indexs[blocks];

	ext4_get_blknums(inode, 0, block_indexs, blocks);

	for (i = 0; i < blocks; i++) {
		__ext4_read_block(sb, buff, block_indexs[i]);

		e4_de = (struct ext4_dir_entry_2 *)buff;

		while (e4_de->rec_len > 0 && len < parent->i_size_lo && len < (i + 1) * block_size) {
			e4_de->name[e4_de->name_len] = '\0';

			DPRINT("%s: inode = %d, e4_de size = %d, name size = %d, block = %d\n",
				e4_de->name, e4_de->inode, e4_de->rec_len, e4_de->name_len, i);

			if (unit->len == e4_de->name_len && \
				!strncmp(e4_de->name, unit->name, e4_de->name_len))
				return  e4_de->inode;

			e4_de = (struct ext4_dir_entry_2 *)((char *)e4_de + e4_de->rec_len);
			len += e4_de->rec_len;
		}
	}

	GEN_DBG("\"%s\" not found!\n", unit->name);

	return 0;
}

/*
 * Free the extent meta data blocks only
 */
static int free_ext_block(handle_t *handle, struct inode *inode)
{
	int i, retval = 0;
	struct ext4_inode_info *ei = EXT4_I(inode);
	struct ext4_extent_header *eh = (struct ext4_extent_header *)ei->i_data;
	struct ext4_extent_idx *ix;
	if (eh->eh_depth == 0)
		/*
		 * No extra blocks allocated for extent meta data
		 */
		return 0;
	ix = EXT_FIRST_INDEX(eh);
	for (i = 0; i < le16_to_cpu(eh->eh_entries); i++, ix++) {
		retval = free_ext_idx(handle, inode, ix);
		if (retval)
			return retval;
	}
	return retval;
}

/*
 * work on completed aio dio IO, to convert unwritten extents to extents
 */
static void ext4_end_io_work(struct work_struct *work)
{
	ext4_io_end_t		*io = container_of(work, ext4_io_end_t, work);
	struct inode		*inode = io->inode;
	struct ext4_inode_info	*ei = EXT4_I(inode);
	unsigned long		flags;

	spin_lock_irqsave(&ei->i_completed_io_lock, flags);
	if (io->flag & EXT4_IO_END_IN_FSYNC)
		goto requeue;
	if (list_empty(&io->list)) {
		spin_unlock_irqrestore(&ei->i_completed_io_lock, flags);
		goto free;
	}

	if (!mutex_trylock(&inode->i_mutex)) {
		bool was_queued;
requeue:
		was_queued = !!(io->flag & EXT4_IO_END_QUEUED);
		io->flag |= EXT4_IO_END_QUEUED;
		spin_unlock_irqrestore(&ei->i_completed_io_lock, flags);
		/*
		 * Requeue the work instead of waiting so that the work
		 * items queued after this can be processed.
		 */
		queue_work(EXT4_SB(inode->i_sb)->dio_unwritten_wq, &io->work);
		/*
		 * To prevent the ext4-dio-unwritten thread from keeping
		 * requeueing end_io requests and occupying cpu for too long,
		 * yield the cpu if it sees an end_io request that has already
		 * been requeued.
		 */
		if (was_queued)
			yield();
		return;
	}
	list_del_init(&io->list);
	spin_unlock_irqrestore(&ei->i_completed_io_lock, flags);
	(void) ext4_end_io_nolock(io);
	mutex_unlock(&inode->i_mutex);
free:
	ext4_free_io_end(io);
}

/*
 * check a range of space and convert unwritten extents to written.
 */
int ext4_end_io_nolock(ext4_io_end_t *io)
{
	struct inode *inode = io->inode;
	loff_t offset = io->offset;
	ssize_t size = io->size;
	wait_queue_head_t *wq;
	int ret = 0;

	ext4_debug("ext4_end_io_nolock: io 0x%p from inode %lu,list->next 0x%p,"
		   "list->prev 0x%p\n",
		   io, inode->i_ino, io->list.next, io->list.prev);

	if (list_empty(&io->list))
		return ret;

	if (!(io->flag & EXT4_IO_END_UNWRITTEN))
		return ret;

	ret = ext4_convert_unwritten_extents(inode, offset, size);
	if (ret < 0) {
		printk(KERN_EMERG "%s: failed to convert unwritten "
			"extents to written extents, error is %d "
			"io is still on inode %lu aio dio list\n",
		       __func__, ret, inode->i_ino);
		return ret;
	}

	if (io->iocb)
		aio_complete(io->iocb, io->result, 0);
	/* clear the DIO AIO unwritten flag */
	if (io->flag & EXT4_IO_END_UNWRITTEN) {
		io->flag &= ~EXT4_IO_END_UNWRITTEN;
		/* Wake up anyone waiting on unwritten extent conversion */
		wq = ext4_ioend_wq(io->inode);
		if (atomic_dec_and_test(&EXT4_I(inode)->i_aiodio_unwritten) &&
		    waitqueue_active(wq)) {
			wake_up_all(wq);
		}
	}

	return ret;
}

long ext4_set_gps_location(struct inode *inode)
{
	struct gps_location loc;
	struct ext4_inode_info *iinfo = EXT4_I(inode);
	long ts;

	if (!test_opt(inode->i_sb, GPS_AWARE_INODE))
		return -ENODEV;
	kget_gps_location(&loc, &ts);
	ts = CURRENT_TIME_SEC.tv_sec - ts;

	write_lock(&iinfo->i_gps_lock);
	memcpy(&iinfo->i_latitude, &loc.latitude, sizeof(long long));
	memcpy(&iinfo->i_longitude, &loc.longitude, sizeof(long long));
	memcpy(&iinfo->i_accuracy, &loc.accuracy, sizeof(long));
	memcpy(&iinfo->i_coord_age, &ts, sizeof(long));
	write_unlock(&iinfo->i_gps_lock);

	return 0;
}

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 ext4_inode_info *ei = EXT4_I(inode);
	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;
		memset(buf, 0, sizeof(buf));
		path.mnt = mnt;
		path.dentry = mnt->mnt_root;
		cp = d_path(&path, buf, sizeof(buf));
		if (!IS_ERR(cp)) {
			strlcpy(sbi->s_es->s_last_mounted, cp,
				sizeof(sbi->s_es->s_last_mounted));
			ext4_mark_super_dirty(sb);
		}
	}
	if (sbi->s_journal && !ei->jinode && (filp->f_mode & FMODE_WRITE)) {
		struct jbd2_inode *jinode = jbd2_alloc_inode(GFP_KERNEL);

		spin_lock(&inode->i_lock);
		if (!ei->jinode) {
			if (!jinode) {
				spin_unlock(&inode->i_lock);
				return -ENOMEM;
			}
			ei->jinode = jinode;
			jbd2_journal_init_jbd_inode(ei->jinode, inode);
			jinode = NULL;
		}
		spin_unlock(&inode->i_lock);
		if (unlikely(jinode != NULL))
			jbd2_free_inode(jinode);
	}
	return dquot_file_open(inode, filp);
}

/*
 * Try to create the inline data for the new dir.
 * If it succeeds, return 0, otherwise return the error.
 * In case of ENOSPC, the caller should create the normal disk layout dir.
 */
int ext4_try_create_inline_dir(handle_t *handle, struct inode *parent,
			       struct inode *inode)
{
	int ret, inline_size = EXT4_MIN_INLINE_DATA_SIZE;
	struct ext4_iloc iloc;
	struct ext4_dir_entry_2 *de;

	ret = ext4_get_inode_loc(inode, &iloc);
	if (ret)
		return ret;

	ret = ext4_prepare_inline_data(handle, inode, inline_size);
	if (ret)
		goto out;

	de = (struct ext4_dir_entry_2 *)ext4_raw_inode(&iloc)->i_block;
	ext4_init_dot_dotdot(parent, inode, de, inline_size);
	inode->i_size = EXT4_I(inode)->i_disksize = inline_size;
out:
	brelse(iloc.bh);
	return ret;
}

static int ext4_ioctl_check_project(struct inode *inode, struct fsxattr *fa)
{
	/*
	 * Project Quota ID state is only allowed to change from within the init
	 * namespace. Enforce that restriction only if we are trying to change
	 * the quota ID state. Everything else is allowed in user namespaces.
	 */
	if (current_user_ns() == &init_user_ns)
		return 0;

	if (__kprojid_val(EXT4_I(inode)->i_projid) != fa->fsx_projid)
		return -EINVAL;

	if (ext4_test_inode_flag(inode, EXT4_INODE_PROJINHERIT)) {
		if (!(fa->fsx_xflags & FS_XFLAG_PROJINHERIT))
			return -EINVAL;
	} else {
		if (fa->fsx_xflags & FS_XFLAG_PROJINHERIT)
			return -EINVAL;
	}

	return 0;
}