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Commit 2c887e23 authored by KaiGai Kohei's avatar KaiGai Kohei Committed by David Woodhouse
Browse files

[JFFS2][XATTR] Re-define xd->refcnt as atomic_t 



In jffs2_release_xattr_datum(), it refers xd->refcnt to ensure
whether releasing xd is allowed or not.
But we can't hold xattr_sem since this function is called under
spin_lock(&c->erase_completion_lock). Thus we have to refer it
without any locking.

This patch redefine xd->refcnt as atomic_t. It enables to refer
xd->refcnt without any locking.

Signed-off-by: default avatarKaiGai Kohei <kaigai@ak.jp.nec.com>
Signed-off-by: default avatarDavid Woodhouse <dwmw2@infradead.org>
parent 355ed4e1

fs/jffs2/xattr.c

+11 −14
Original line number Diff line number Diff line
@@ -345,7 +345,7 @@ static struct jffs2_xattr_datum *create_xattr_datum(struct jffs2_sb_info *c, 
		    && xd->value_len==xsize

		    && !strcmp(xd->xname, xname)

		    && !memcmp(xd->xvalue, xvalue, xsize)) {

			xd->refcnt++;

			atomic_inc(&xd->refcnt);

			return xd;

		}

	}
@@ -365,7 +365,7 @@ static struct jffs2_xattr_datum *create_xattr_datum(struct jffs2_sb_info *c, 
	strcpy(data, xname);

	memcpy(data + name_len + 1, xvalue, xsize);



	xd->refcnt = 1;

	atomic_set(&xd->refcnt, 1);

	xd->xid = ++c->highest_xid;

	xd->flags |= JFFS2_XFLAGS_HOT;

	xd->xprefix = xprefix;
@@ -397,7 +397,7 @@ static struct jffs2_xattr_datum *create_xattr_datum(struct jffs2_sb_info *c, 
static void delete_xattr_datum(struct jffs2_sb_info *c, struct jffs2_xattr_datum *xd)

{

	/* must be called under down_write(xattr_sem) */

	BUG_ON(xd->refcnt);

	BUG_ON(atomic_read(&xd->refcnt));



	unload_xattr_datum(c, xd);

	xd->flags |= JFFS2_XFLAGS_DEAD;
@@ -580,7 +580,7 @@ static void delete_xattr_ref(struct jffs2_sb_info *c, struct jffs2_xattr_ref *re 
	dbg_xattr("xref(ino=%u, xid=%u, xseqno=%u) was removed.\n",

		  ref->ino, ref->xid, ref->xseqno);



	if (!--xd->refcnt)

	if (atomic_dec_and_test(&xd->refcnt))

		delete_xattr_datum(c, xd);

}
@@ -612,8 +612,7 @@ void jffs2_xattr_free_inode(struct jffs2_sb_info *c, struct jffs2_inode_cache *i 
	for (ref = ic->xref; ref; ref = _ref) {

		_ref = ref->next;

		xd = ref->xd;

		xd->refcnt--;

		if (!xd->refcnt) {

		if (atomic_dec_and_test(&xd->refcnt)) {

			unload_xattr_datum(c, xd);

			jffs2_free_xattr_datum(xd);

		}
@@ -835,7 +834,7 @@ void jffs2_build_xattr_subsystem(struct jffs2_sb_info *c) 
			}

			ref->xd = xd;

			ref->ic = ic;

			xd->refcnt++;

			atomic_inc(&xd->refcnt);

			ref->next = ic->xref;

			ic->xref = ref;

		}
@@ -846,7 +845,7 @@ void jffs2_build_xattr_subsystem(struct jffs2_sb_info *c) 
		list_for_each_entry_safe(xd, _xd, &c->xattrindex[i], xindex) {

			xdatum_count++;

			list_del_init(&xd->xindex);

			if (!xd->refcnt) {

			if (!atomic_read(&xd->refcnt)) {

				dbg_xattr("xdatum(xid=%u, version=%u) is orphan.\n",

					  xd->xid, xd->version);

				xd->flags |= JFFS2_XFLAGS_DEAD;
@@ -1120,7 +1119,7 @@ int do_jffs2_setxattr(struct inode *inode, int xprefix, const char *xname, 
					ref->next = c->xref_dead_list;

					c->xref_dead_list = ref;

					spin_unlock(&c->erase_completion_lock);

					if (!--xd->refcnt)

					if (atomic_dec_and_test(&xd->refcnt))

						delete_xattr_datum(c, xd);

				} else {

					ref->ic = ic;
@@ -1157,8 +1156,7 @@ int do_jffs2_setxattr(struct inode *inode, int xprefix, const char *xname, 
	down_write(&c->xattr_sem);

	if (rc) {

		JFFS2_WARNING("jffs2_reserve_space()=%d, request=%u\n", rc, request);

		xd->refcnt--;

		if (!xd->refcnt)

		if (atomic_dec_and_test(&xd->refcnt))

			delete_xattr_datum(c, xd);

		up_write(&c->xattr_sem);

		return rc;
@@ -1172,8 +1170,7 @@ int do_jffs2_setxattr(struct inode *inode, int xprefix, const char *xname, 
			ic->xref = ref;

		}

		rc = PTR_ERR(newref);

		xd->refcnt--;

		if (!xd->refcnt)

		if (atomic_dec_and_test(&xd->refcnt))

			delete_xattr_datum(c, xd);

	} else if (ref) {

		delete_xattr_ref(c, ref);
@@ -1304,7 +1301,7 @@ int jffs2_verify_xattr(struct jffs2_sb_info *c) 
void jffs2_release_xattr_datum(struct jffs2_sb_info *c, struct jffs2_xattr_datum *xd)

{

	/* must be called under spin_lock(&c->erase_completion_lock) */

	if (xd->refcnt > 0 || xd->node != (void *)xd)

	if (atomic_read(&xd->refcnt) || xd->node != (void *)xd)

		return;



	list_del(&xd->xindex);

fs/jffs2/xattr.h

+1 −1
Original line number Diff line number Diff line
@@ -28,7 +28,7 @@ struct jffs2_xattr_datum 
	uint16_t xprefix;		/* see JFFS2_XATTR_PREFIX_* */



	struct list_head xindex;	/* chained from c->xattrindex[n] */

	uint32_t refcnt;		/* # of xattr_ref refers this */

	atomic_t refcnt;		/* # of xattr_ref refers this */

	uint32_t xid;

	uint32_t version;