예제 #1
0
/* unionfs_open helper function: open a directory */
static int __open_dir(struct inode *inode, struct file *file)
{
	struct dentry *lower_dentry;
	struct file *lower_file;
	int bindex, bstart, bend;
	struct vfsmount *mnt;

	bstart = fbstart(file) = dbstart(file->f_path.dentry);
	bend = fbend(file) = dbend(file->f_path.dentry);

	for (bindex = bstart; bindex <= bend; bindex++) {
		lower_dentry =
			unionfs_lower_dentry_idx(file->f_path.dentry, bindex);
		if (!lower_dentry)
			continue;

		dget(lower_dentry);
		unionfs_mntget(file->f_path.dentry, bindex);
		mnt = unionfs_lower_mnt_idx(file->f_path.dentry, bindex);
		lower_file = dentry_open(lower_dentry, mnt, file->f_flags,
					 current_cred());
		if (IS_ERR(lower_file))
			return PTR_ERR(lower_file);

		unionfs_set_lower_file_idx(file, bindex, lower_file);

		/*
		 * The branchget goes after the open, because otherwise
		 * we would miss the reference on release.
		 */
		branchget(inode->i_sb, bindex);
	}

	return 0;
}
예제 #2
0
/* open all lower files for a given file */
static int open_all_files(struct file *file)
{
	int bindex, bstart, bend, err = 0;
	struct file *lower_file;
	struct dentry *lower_dentry;
	struct dentry *dentry = file->f_path.dentry;
	struct super_block *sb = dentry->d_sb;

	bstart = dbstart(dentry);
	bend = dbend(dentry);

	for (bindex = bstart; bindex <= bend; bindex++) {
		lower_dentry = unionfs_lower_dentry_idx(dentry, bindex);
		if (!lower_dentry)
			continue;

		dget(lower_dentry);
		unionfs_mntget(dentry, bindex);
		branchget(sb, bindex);

		lower_file =
			dentry_open(lower_dentry,
				    unionfs_lower_mnt_idx(dentry, bindex),
				    file->f_flags, current_cred());
		if (IS_ERR(lower_file)) {
			branchput(sb, bindex);
			err = PTR_ERR(lower_file);
			goto out;
		} else {
			unionfs_set_lower_file_idx(file, bindex, lower_file);
		}
	}
out:
	return err;
}
예제 #3
0
/* open the highest priority file for a given upper file */
static int open_highest_file(struct file *file, bool willwrite)
{
	int bindex, bstart, bend, err = 0;
	struct file *lower_file;
	struct dentry *lower_dentry;
	struct dentry *dentry = file->f_path.dentry;
	struct dentry *parent = dget_parent(dentry);
	struct inode *parent_inode = parent->d_inode;
	struct super_block *sb = dentry->d_sb;

	bstart = dbstart(dentry);
	bend = dbend(dentry);

	lower_dentry = unionfs_lower_dentry(dentry);
	if (willwrite && IS_WRITE_FLAG(file->f_flags) && is_robranch(dentry)) {
		for (bindex = bstart - 1; bindex >= 0; bindex--) {
			err = copyup_file(parent_inode, file, bstart, bindex,
					  i_size_read(dentry->d_inode));
			if (!err)
				break;
		}
		atomic_set(&UNIONFS_F(file)->generation,
			   atomic_read(&UNIONFS_I(dentry->d_inode)->
				       generation));
		goto out;
	}

	dget(lower_dentry);
	unionfs_mntget(dentry, bstart);
	lower_file = dentry_open(lower_dentry,
				 unionfs_lower_mnt_idx(dentry, bstart),
				 file->f_flags, current_cred());
	if (IS_ERR(lower_file)) {
		err = PTR_ERR(lower_file);
		goto out;
	}
	branchget(sb, bstart);
	unionfs_set_lower_file(file, lower_file);
	/* Fix up the position. */
	lower_file->f_pos = file->f_pos;

	memcpy(&lower_file->f_ra, &file->f_ra, sizeof(struct file_ra_state));
out:
	dput(parent);
	return err;
}
예제 #4
0
/*
 * Post-copyup helper to ensure we have valid mnts: set lower mnt of
 * dentry+parents to the first parent node that has an mnt.
 */
void unionfs_postcopyup_setmnt(struct dentry *dentry)
{
	struct dentry *parent, *hasone;
	int bindex = dbstart(dentry);

	if (unionfs_lower_mnt_idx(dentry, bindex))
		return;
	hasone = dentry->d_parent;
	/* this loop should stop at root dentry */
	while (!unionfs_lower_mnt_idx(hasone, bindex))
		hasone = hasone->d_parent;
	parent = dentry;
	while (!unionfs_lower_mnt_idx(parent, bindex)) {
		unionfs_set_lower_mnt_idx(parent, bindex,
					  unionfs_mntget(hasone, bindex));
		parent = parent->d_parent;
	}
}
예제 #5
0
파일: lookup.c 프로젝트: Mr-Aloof/wl500g
/*
 * Main (and complex) driver function for Unionfs's lookup
 *
 * Returns: NULL (ok), ERR_PTR if an error occurred, or a non-null non-error
 * PTR if d_splice returned a different dentry.
 *
 * If lookupmode is INTERPOSE_PARTIAL/REVAL/REVAL_NEG, the passed dentry's
 * inode info must be locked.  If lookupmode is INTERPOSE_LOOKUP (i.e., a
 * newly looked-up dentry), then unionfs_lookup_backend will return a locked
 * dentry's info, which the caller must unlock.
 */
struct dentry *unionfs_lookup_full(struct dentry *dentry,
				   struct dentry *parent, int lookupmode)
{
	int err = 0;
	struct dentry *lower_dentry = NULL;
	struct vfsmount *lower_mnt;
	struct vfsmount *lower_dir_mnt;
	struct dentry *wh_lower_dentry = NULL;
	struct dentry *lower_dir_dentry = NULL;
	struct dentry *d_interposed = NULL;
	int bindex, bstart, bend, bopaque;
	int opaque, num_positive = 0;
	const char *name;
	int namelen;
	int pos_start, pos_end;

	/*
	 * We should already have a lock on this dentry in the case of a
	 * partial lookup, or a revalidation.  Otherwise it is returned from
	 * new_dentry_private_data already locked.
	 */
	verify_locked(dentry);
	verify_locked(parent);

	/* must initialize dentry operations */
	dentry->d_op = &unionfs_dops;

	/* We never partial lookup the root directory. */
	if (IS_ROOT(dentry))
		goto out;

	name = dentry->d_name.name;
	namelen = dentry->d_name.len;

	/* No dentries should get created for possible whiteout names. */
	if (!is_validname(name)) {
		err = -EPERM;
		goto out_free;
	}

	/* Now start the actual lookup procedure. */
	bstart = dbstart(parent);
	bend = dbend(parent);
	bopaque = dbopaque(parent);
	BUG_ON(bstart < 0);

	/* adjust bend to bopaque if needed */
	if ((bopaque >= 0) && (bopaque < bend))
		bend = bopaque;

	/* lookup all possible dentries */
	for (bindex = bstart; bindex <= bend; bindex++) {

		lower_dentry = unionfs_lower_dentry_idx(dentry, bindex);
		lower_mnt = unionfs_lower_mnt_idx(dentry, bindex);

		/* skip if we already have a positive lower dentry */
		if (lower_dentry) {
			if (dbstart(dentry) < 0)
				dbstart(dentry) = bindex;
			if (bindex > dbend(dentry))
				dbend(dentry) = bindex;
			if (lower_dentry->d_inode)
				num_positive++;
			continue;
		}

		lower_dir_dentry =
			unionfs_lower_dentry_idx(parent, bindex);
		/* if the lower dentry's parent does not exist, skip this */
		if (!lower_dir_dentry || !lower_dir_dentry->d_inode)
			continue;

		/* also skip it if the parent isn't a directory. */
		if (!S_ISDIR(lower_dir_dentry->d_inode->i_mode))
			continue; /* XXX: should be BUG_ON */

		/* check for whiteouts: stop lookup if found */
		wh_lower_dentry = lookup_whiteout(name, lower_dir_dentry);
		if (IS_ERR(wh_lower_dentry)) {
			err = PTR_ERR(wh_lower_dentry);
			goto out_free;
		}
		if (wh_lower_dentry->d_inode) {
			dbend(dentry) = dbopaque(dentry) = bindex;
			if (dbstart(dentry) < 0)
				dbstart(dentry) = bindex;
			dput(wh_lower_dentry);
			break;
		}
		dput(wh_lower_dentry);

		/* Now do regular lookup; lookup @name */
		lower_dir_mnt = unionfs_lower_mnt_idx(parent, bindex);
		lower_mnt = NULL; /* XXX: needed? */

		lower_dentry = __lookup_one(lower_dir_dentry, lower_dir_mnt,
					    name, &lower_mnt);

		if (IS_ERR(lower_dentry)) {
			err = PTR_ERR(lower_dentry);
			goto out_free;
		}
		unionfs_set_lower_dentry_idx(dentry, bindex, lower_dentry);
		if (!lower_mnt)
			lower_mnt = unionfs_mntget(dentry->d_sb->s_root,
						   bindex);
		unionfs_set_lower_mnt_idx(dentry, bindex, lower_mnt);

		/* adjust dbstart/end */
		if (dbstart(dentry) < 0)
			dbstart(dentry) = bindex;
		if (bindex > dbend(dentry))
			dbend(dentry) = bindex;
		/*
		 * We always store the lower dentries above, and update
		 * dbstart/dbend, even if the whole unionfs dentry is
		 * negative (i.e., no lower inodes).
		 */
		if (!lower_dentry->d_inode)
			continue;
		num_positive++;

		/*
		 * check if we just found an opaque directory, if so, stop
		 * lookups here.
		 */
		if (!S_ISDIR(lower_dentry->d_inode->i_mode))
			continue;
		opaque = is_opaque_dir(dentry, bindex);
		if (opaque < 0) {
			err = opaque;
			goto out_free;
		} else if (opaque) {
			dbend(dentry) = dbopaque(dentry) = bindex;
			break;
		}
		dbend(dentry) = bindex;

		/* update parent directory's atime with the bindex */
		fsstack_copy_attr_atime(parent->d_inode,
					lower_dir_dentry->d_inode);
	}

	/* sanity checks, then decide if to process a negative dentry */
	BUG_ON(dbstart(dentry) < 0 && dbend(dentry) >= 0);
	BUG_ON(dbstart(dentry) >= 0 && dbend(dentry) < 0);

	if (num_positive > 0)
		goto out_positive;

	/*** handle NEGATIVE dentries ***/

	/*
	 * If negative, keep only first lower negative dentry, to save on
	 * memory.
	 */
	if (dbstart(dentry) < dbend(dentry)) {
		path_put_lowers(dentry, dbstart(dentry) + 1,
				dbend(dentry), false);
		dbend(dentry) = dbstart(dentry);
	}
	if (lookupmode == INTERPOSE_PARTIAL)
		goto out;
	if (lookupmode == INTERPOSE_LOOKUP) {
		/*
		 * If all we found was a whiteout in the first available
		 * branch, then create a negative dentry for a possibly new
		 * file to be created.
		 */
		if (dbopaque(dentry) < 0)
			goto out;
		/* XXX: need to get mnt here */
		bindex = dbstart(dentry);
		if (unionfs_lower_dentry_idx(dentry, bindex))
			goto out;
		lower_dir_dentry =
			unionfs_lower_dentry_idx(parent, bindex);
		if (!lower_dir_dentry || !lower_dir_dentry->d_inode)
			goto out;
		if (!S_ISDIR(lower_dir_dentry->d_inode->i_mode))
			goto out; /* XXX: should be BUG_ON */
		/* XXX: do we need to cross bind mounts here? */
		lower_dentry = lookup_one_len(name, lower_dir_dentry, namelen);
		if (IS_ERR(lower_dentry)) {
			err = PTR_ERR(lower_dentry);
			goto out;
		}
		/* XXX: need to mntget/mntput as needed too! */
		unionfs_set_lower_dentry_idx(dentry, bindex, lower_dentry);
		/* XXX: wrong mnt for crossing bind mounts! */
		lower_mnt = unionfs_mntget(dentry->d_sb->s_root, bindex);
		unionfs_set_lower_mnt_idx(dentry, bindex, lower_mnt);

		goto out;
	}

	/* if we're revalidating a positive dentry, don't make it negative */
	if (lookupmode != INTERPOSE_REVAL)
		d_add(dentry, NULL);

	goto out;

out_positive:
	/*** handle POSITIVE dentries ***/

	/*
	 * This unionfs dentry is positive (at least one lower inode
	 * exists), so scan entire dentry from beginning to end, and remove
	 * any negative lower dentries, if any.  Then, update dbstart/dbend
	 * to reflect the start/end of positive dentries.
	 */
	pos_start = pos_end = -1;
	for (bindex = bstart; bindex <= bend; bindex++) {
		lower_dentry = unionfs_lower_dentry_idx(dentry,
							bindex);
		if (lower_dentry && lower_dentry->d_inode) {
			if (pos_start < 0)
				pos_start = bindex;
			if (bindex > pos_end)
				pos_end = bindex;
			continue;
		}
		path_put_lowers(dentry, bindex, bindex, false);
	}
	if (pos_start >= 0)
		dbstart(dentry) = pos_start;
	if (pos_end >= 0)
		dbend(dentry) = pos_end;

	/* Partial lookups need to re-interpose, or throw away older negs. */
	if (lookupmode == INTERPOSE_PARTIAL) {
		if (dentry->d_inode) {
			unionfs_reinterpose(dentry);
			goto out;
		}

		/*
		 * This dentry was positive, so it is as if we had a
		 * negative revalidation.
		 */
		lookupmode = INTERPOSE_REVAL_NEG;
		update_bstart(dentry);
	}

	/*
	 * Interpose can return a dentry if d_splice returned a different
	 * dentry.
	 */
	d_interposed = unionfs_interpose(dentry, dentry->d_sb, lookupmode);
	if (IS_ERR(d_interposed))
		err = PTR_ERR(d_interposed);
	else if (d_interposed)
		dentry = d_interposed;

	if (!err)
		goto out;
	d_drop(dentry);

out_free:
	/* should dput/mntput all the underlying dentries on error condition */
	if (dbstart(dentry) >= 0)
		path_put_lowers_all(dentry, false);
	/* free lower_paths unconditionally */
	kfree(UNIONFS_D(dentry)->lower_paths);
	UNIONFS_D(dentry)->lower_paths = NULL;

out:
	if (dentry && UNIONFS_D(dentry)) {
		BUG_ON(dbstart(dentry) < 0 && dbend(dentry) >= 0);
		BUG_ON(dbstart(dentry) >= 0 && dbend(dentry) < 0);
	}
	if (d_interposed && UNIONFS_D(d_interposed)) {
		BUG_ON(dbstart(d_interposed) < 0 && dbend(d_interposed) >= 0);
		BUG_ON(dbstart(d_interposed) >= 0 && dbend(d_interposed) < 0);
	}

	if (!err && d_interposed)
		return d_interposed;
	return ERR_PTR(err);
}
예제 #6
0
/* Is a directory logically empty? */
int check_empty(struct dentry *dentry, struct dentry *parent,
		struct unionfs_dir_state **namelist)
{
	int err = 0;
	struct dentry *lower_dentry = NULL;
	struct vfsmount *mnt;
	struct super_block *sb;
	struct file *lower_file;
	struct unionfs_rdutil_callback *buf = NULL;
	int bindex, bstart, bend, bopaque;

	sb = dentry->d_sb;


	BUG_ON(!S_ISDIR(dentry->d_inode->i_mode));

	err = unionfs_partial_lookup(dentry, parent);
	if (err)
		goto out;

	bstart = dbstart(dentry);
	bend = dbend(dentry);
	bopaque = dbopaque(dentry);
	if (0 <= bopaque && bopaque < bend)
		bend = bopaque;

	buf = kmalloc(sizeof(struct unionfs_rdutil_callback), GFP_KERNEL);
	if (unlikely(!buf)) {
		err = -ENOMEM;
		goto out;
	}
	buf->err = 0;
	buf->mode = RD_CHECK_EMPTY;
	buf->rdstate = alloc_rdstate(dentry->d_inode, bstart);
	if (unlikely(!buf->rdstate)) {
		err = -ENOMEM;
		goto out;
	}

	/* Process the lower directories with rdutil_callback as a filldir. */
	for (bindex = bstart; bindex <= bend; bindex++) {
		lower_dentry = unionfs_lower_dentry_idx(dentry, bindex);
		if (!lower_dentry)
			continue;
		if (!lower_dentry->d_inode)
			continue;
		if (!S_ISDIR(lower_dentry->d_inode->i_mode))
			continue;

		dget(lower_dentry);
		mnt = unionfs_mntget(dentry, bindex);
		branchget(sb, bindex);
		lower_file = dentry_open(lower_dentry, mnt, O_RDONLY);
		if (IS_ERR(lower_file)) {
			err = PTR_ERR(lower_file);
			branchput(sb, bindex);
			goto out;
		}

		do {
			buf->filldir_called = 0;
			buf->rdstate->bindex = bindex;
			err = vfs_readdir(lower_file,
					  readdir_util_callback, buf);
			if (buf->err)
				err = buf->err;
		} while ((err >= 0) && buf->filldir_called);

		/* fput calls dput for lower_dentry */
		fput(lower_file);
		branchput(sb, bindex);

		if (err < 0)
			goto out;
	}

out:
	if (buf) {
		if (namelist && !err)
			*namelist = buf->rdstate;
		else if (buf->rdstate)
			free_rdstate(buf->rdstate);
		kfree(buf);
	}


	return err;
}
예제 #7
0
static int __copyup_reg_data(struct dentry *dentry,
			     struct dentry *new_lower_dentry, int new_bindex,
			     struct dentry *old_lower_dentry, int old_bindex,
			     struct file **copyup_file, loff_t len)
{
	struct super_block *sb = dentry->d_sb;
	struct file *input_file;
	struct file *output_file;
	struct vfsmount *output_mnt;
	mm_segment_t old_fs;
	char *buf = NULL;
	ssize_t read_bytes, write_bytes;
	loff_t size;
	int err = 0;

	/* open old file */
	unionfs_mntget(dentry, old_bindex);
	branchget(sb, old_bindex);
	/* dentry_open calls dput and mntput if it returns an error */
	input_file = dentry_open(old_lower_dentry,
				 unionfs_lower_mnt_idx(dentry, old_bindex),
				 O_RDONLY | O_LARGEFILE);
	if (IS_ERR(input_file)) {
		dput(old_lower_dentry);
		err = PTR_ERR(input_file);
		goto out;
	}
	if (unlikely(!input_file->f_op || !input_file->f_op->read)) {
		err = -EINVAL;
		goto out_close_in;
	}

	/* open new file */
	dget(new_lower_dentry);
	output_mnt = unionfs_mntget(sb->s_root, new_bindex);
	branchget(sb, new_bindex);
	output_file = dentry_open(new_lower_dentry, output_mnt,
				  O_RDWR | O_LARGEFILE);
	if (IS_ERR(output_file)) {
		err = PTR_ERR(output_file);
		goto out_close_in2;
	}
	if (unlikely(!output_file->f_op || !output_file->f_op->write)) {
		err = -EINVAL;
		goto out_close_out;
	}

	/* allocating a buffer */
	buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
	if (unlikely(!buf)) {
		err = -ENOMEM;
		goto out_close_out;
	}

	input_file->f_pos = 0;
	output_file->f_pos = 0;

	old_fs = get_fs();
	set_fs(KERNEL_DS);

	size = len;
	err = 0;
	do {
		if (len >= PAGE_SIZE)
			size = PAGE_SIZE;
		else if ((len < PAGE_SIZE) && (len > 0))
			size = len;

		len -= PAGE_SIZE;

		read_bytes =
			input_file->f_op->read(input_file,
					       (char __user *)buf, size,
					       &input_file->f_pos);
		if (read_bytes <= 0) {
			err = read_bytes;
			break;
		}

		/* see Documentation/filesystems/unionfs/issues.txt */
		lockdep_off();
		write_bytes =
			output_file->f_op->write(output_file,
						 (char __user *)buf,
						 read_bytes,
						 &output_file->f_pos);
		lockdep_on();
		if ((write_bytes < 0) || (write_bytes < read_bytes)) {
			err = write_bytes;
			break;
		}
	} while ((read_bytes > 0) && (len > 0));

	set_fs(old_fs);

	kfree(buf);

	if (!err)
		err = output_file->f_op->fsync(output_file,
					       new_lower_dentry, 0);

	if (err)
		goto out_close_out;

	if (copyup_file) {
		*copyup_file = output_file;
		goto out_close_in;
	}

out_close_out:
	fput(output_file);

out_close_in2:
	branchput(sb, new_bindex);

out_close_in:
	fput(input_file);

out:
	branchput(sb, old_bindex);

	return err;
}
예제 #8
0
/* unionfs_open helper function: open a file */
static int __open_file(struct inode *inode, struct file *file,
		       struct dentry *parent)
{
	struct dentry *lower_dentry;
	struct file *lower_file;
	int lower_flags;
	int bindex, bstart, bend;

	lower_dentry = unionfs_lower_dentry(file->f_path.dentry);
	lower_flags = file->f_flags;

	bstart = fbstart(file) = dbstart(file->f_path.dentry);
	bend = fbend(file) = dbend(file->f_path.dentry);

	/*
	 * check for the permission for lower file.  If the error is
	 * COPYUP_ERR, copyup the file.
	 */
	if (lower_dentry->d_inode && is_robranch(file->f_path.dentry)) {
		/*
		 * if the open will change the file, copy it up otherwise
		 * defer it.
		 */
		if (lower_flags & O_TRUNC) {
			int size = 0;
			int err = -EROFS;

			/* copyup the file */
			for (bindex = bstart - 1; bindex >= 0; bindex--) {
				err = copyup_file(parent->d_inode, file,
						  bstart, bindex, size);
				if (!err) {
					/* only one regular file open */
					fbend(file) = fbstart(file);
					break;
				}
			}
			return err;
		} else {
			/*
			 * turn off writeable flags, to force delayed copyup
			 * by caller.
			 */
			lower_flags &= ~(OPEN_WRITE_FLAGS);
		}
	}

	dget(lower_dentry);

	/*
	 * dentry_open will decrement mnt refcnt if err.
	 * otherwise fput() will do an mntput() for us upon file close.
	 */
	unionfs_mntget(file->f_path.dentry, bstart);
	lower_file =
		dentry_open(lower_dentry,
			    unionfs_lower_mnt_idx(file->f_path.dentry, bstart),
			    lower_flags, current_cred());
	if (IS_ERR(lower_file))
		return PTR_ERR(lower_file);

	unionfs_set_lower_file(file, lower_file);
	branchget(inode->i_sb, bstart);

	return 0;
}
예제 #9
0
/*
 * Helper function for unionfs_file_revalidate/locked.
 * Expects dentry/parent to be locked already, and revalidated.
 */
static int __unionfs_file_revalidate(struct file *file, struct dentry *dentry,
				     struct dentry *parent,
				     struct super_block *sb, int sbgen,
				     int dgen, bool willwrite)
{
	int fgen;
	int bstart, bend, orig_brid;
	int size;
	int err = 0;

	fgen = atomic_read(&UNIONFS_F(file)->generation);

	/*
	 * There are two cases we are interested in.  The first is if the
	 * generation is lower than the super-block.  The second is if
	 * someone has copied up this file from underneath us, we also need
	 * to refresh things.
	 */
	if (d_deleted(dentry) ||
	    (sbgen <= fgen &&
	     dbstart(dentry) == fbstart(file) &&
	     unionfs_lower_file(file)))
		goto out_may_copyup;

	/* save orig branch ID */
	orig_brid = UNIONFS_F(file)->saved_branch_ids[fbstart(file)];

	/* First we throw out the existing files. */
	cleanup_file(file);

	/* Now we reopen the file(s) as in unionfs_open. */
	bstart = fbstart(file) = dbstart(dentry);
	bend = fbend(file) = dbend(dentry);

	size = sizeof(struct file *) * sbmax(sb);
	UNIONFS_F(file)->lower_files = kzalloc(size, GFP_KERNEL);
	if (unlikely(!UNIONFS_F(file)->lower_files)) {
		err = -ENOMEM;
		goto out;
	}
	size = sizeof(int) * sbmax(sb);
	UNIONFS_F(file)->saved_branch_ids = kzalloc(size, GFP_KERNEL);
	if (unlikely(!UNIONFS_F(file)->saved_branch_ids)) {
		err = -ENOMEM;
		goto out;
	}

	if (S_ISDIR(dentry->d_inode->i_mode)) {
		/* We need to open all the files. */
		err = open_all_files(file);
		if (err)
			goto out;
	} else {
		int new_brid;
		/* We only open the highest priority branch. */
		err = open_highest_file(file, willwrite);
		if (err)
			goto out;
		new_brid = UNIONFS_F(file)->saved_branch_ids[fbstart(file)];
		if (unlikely(new_brid != orig_brid && sbgen > fgen)) {
			/*
			 * If we re-opened the file on a different branch
			 * than the original one, and this was due to a new
			 * branch inserted, then update the mnt counts of
			 * the old and new branches accordingly.
			 */
			unionfs_mntget(dentry, bstart);
			unionfs_mntput(sb->s_root,
				       branch_id_to_idx(sb, orig_brid));
		}
		/* regular files have only one open lower file */
		fbend(file) = fbstart(file);
	}
	atomic_set(&UNIONFS_F(file)->generation,
		   atomic_read(&UNIONFS_I(dentry->d_inode)->generation));

out_may_copyup:
	/* Copyup on the first write to a file on a readonly branch. */
	if (willwrite && IS_WRITE_FLAG(file->f_flags) &&
	    !IS_WRITE_FLAG(unionfs_lower_file(file)->f_flags) &&
	    is_robranch(dentry)) {
		pr_debug("unionfs: do delay copyup of \"%s\"\n",
			 dentry->d_name.name);
		err = do_delayed_copyup(file, parent);
		/* regular files have only one open lower file */
		if (!err && !S_ISDIR(dentry->d_inode->i_mode))
			fbend(file) = fbstart(file);
	}

out:
	if (err) {
		kfree(UNIONFS_F(file)->lower_files);
		kfree(UNIONFS_F(file)->saved_branch_ids);
	}
	return err;
}
예제 #10
0
/* Is a directory logically empty? */
int check_empty(struct dentry *dentry, struct dentry *parent,
		struct unionfs_dir_state **namelist)
{
	int err = 0;
	struct dentry *lower_dentry = NULL;
	struct vfsmount *mnt;
	struct super_block *sb;
	struct file *lower_file;
	struct unionfs_rdutil_callback buf = {
		.ctx.actor = readdir_util_callback,
	};
	int bindex, bstart, bend, bopaque;
	struct path path;

	sb = dentry->d_sb;


	BUG_ON(!S_ISDIR(dentry->d_inode->i_mode));

	err = unionfs_partial_lookup(dentry, parent);
	if (err)
		goto out;

	bstart = dbstart(dentry);
	bend = dbend(dentry);
	bopaque = dbopaque(dentry);
	if (0 <= bopaque && bopaque < bend)
		bend = bopaque;

	buf.err = 0;
	buf.filldir_called = 0;
	buf.mode = RD_CHECK_EMPTY;
	buf.ctx.pos = 0; /* XXX: needed?! */
	buf.rdstate = alloc_rdstate(dentry->d_inode, bstart);
	if (unlikely(!buf.rdstate)) {
		err = -ENOMEM;
		goto out;
	}

	/* Process the lower directories with rdutil_callback as a filldir. */
	for (bindex = bstart; bindex <= bend; bindex++) {
		lower_dentry = unionfs_lower_dentry_idx(dentry, bindex);
		if (!lower_dentry)
			continue;
		if (!lower_dentry->d_inode)
			continue;
		if (!S_ISDIR(lower_dentry->d_inode->i_mode))
			continue;

		dget(lower_dentry);
		mnt = unionfs_mntget(dentry, bindex);
		branchget(sb, bindex);
		path.dentry = lower_dentry;
		path.mnt = mnt;
		lower_file = dentry_open(&path, O_RDONLY, current_cred());
		path_put(&path);
		if (IS_ERR(lower_file)) {
			err = PTR_ERR(lower_file);
			branchput(sb, bindex);
			goto out;
		}

		do {
			buf.filldir_called = 0;
			buf.rdstate->bindex = bindex;
			err = iterate_dir(lower_file, &buf.ctx);
			if (buf.err)
				err = buf.err;
		} while ((err >= 0) && buf.filldir_called);

		/* fput calls dput for lower_dentry */
		fput(lower_file);
		branchput(sb, bindex);

		if (err < 0)
			goto out;
	}

out:
	if (namelist && !err)
		*namelist = buf.rdstate;
	else if (buf.rdstate)
		free_rdstate(buf.rdstate);

	return err;
}