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Commit 24b33ee1 authored by Amir Goldstein's avatar Amir Goldstein Committed by Miklos Szeredi
Browse files

ovl: create ovl_need_index() helper 



The helper determines which lower file needs to be indexed
on copy up and before nlink changes.

For index=on, the helper evaluates to true for lower hardlinks.

Signed-off-by: default avatarAmir Goldstein <amir73il@gmail.com>
Signed-off-by: default avatarMiklos Szeredi <mszeredi@redhat.com>
parent 9ee60ce2

fs/overlayfs/copy_up.c

+1 −5
Original line number Diff line number Diff line
@@ -536,11 +536,7 @@ static int ovl_do_copy_up(struct ovl_copy_up_ctx *c) 
{

	int err;

	struct ovl_fs *ofs = c->dentry->d_sb->s_fs_info;

	bool indexed = false;



	if (ovl_indexdir(c->dentry->d_sb) && !S_ISDIR(c->stat.mode) &&

	    c->stat.nlink > 1)

		indexed = true;

	bool indexed = ovl_need_index(c->dentry);



	if (S_ISDIR(c->stat.mode) || c->stat.nlink == 1 || indexed)

		c->origin = true;

fs/overlayfs/overlayfs.h

+1 −0
Original line number Diff line number Diff line
@@ -241,6 +241,7 @@ void ovl_clear_flag(unsigned long flag, struct inode *inode); 
bool ovl_test_flag(unsigned long flag, struct inode *inode);

bool ovl_inuse_trylock(struct dentry *dentry);

void ovl_inuse_unlock(struct dentry *dentry);

bool ovl_need_index(struct dentry *dentry);

int ovl_nlink_start(struct dentry *dentry, bool *locked);

void ovl_nlink_end(struct dentry *dentry, bool locked);

int ovl_lock_rename_workdir(struct dentry *workdir, struct dentry *upperdir);

fs/overlayfs/util.c

+20 −4
Original line number Diff line number Diff line
@@ -463,6 +463,23 @@ void ovl_inuse_unlock(struct dentry *dentry) 
	}

}



/*

 * Does this overlay dentry need to be indexed on copy up?

 */

bool ovl_need_index(struct dentry *dentry)

{

	struct dentry *lower = ovl_dentry_lower(dentry);



	if (!lower || !ovl_indexdir(dentry->d_sb))

		return false;



	/* Index only lower hardlinks on copy up */

	if (!d_is_dir(lower) && d_inode(lower)->i_nlink > 1)

		return true;



	return false;

}



/* Caller must hold OVL_I(inode)->lock */

static void ovl_cleanup_index(struct dentry *dentry)

{
@@ -533,11 +550,11 @@ int ovl_nlink_start(struct dentry *dentry, bool *locked) 


	/*

	 * With inodes index is enabled, we store the union overlay nlink

	 * in an xattr on the index inode. When whiting out lower hardlinks

	 * in an xattr on the index inode. When whiting out an indexed lower,

	 * we need to decrement the overlay persistent nlink, but before the

	 * first copy up, we have no upper index inode to store the xattr.

	 *

	 * As a workaround, before whiteout/rename over of a lower hardlink,

	 * As a workaround, before whiteout/rename over an indexed lower,

	 * copy up to create the upper index. Creating the upper index will

	 * initialize the overlay nlink, so it could be dropped if unlink

	 * or rename succeeds.
@@ -545,8 +562,7 @@ int ovl_nlink_start(struct dentry *dentry, bool *locked) 
	 * TODO: implement metadata only index copy up when called with

	 *       ovl_copy_up_flags(dentry, O_PATH).

	 */

	if (ovl_indexdir(dentry->d_sb) && !ovl_dentry_has_upper_alias(dentry) &&

	    d_inode(ovl_dentry_lower(dentry))->i_nlink > 1) {

	if (ovl_need_index(dentry) && !ovl_dentry_has_upper_alias(dentry)) {

		err = ovl_copy_up(dentry);

		if (err)

			return err;