[XFS] shrink mrlock_t

The writer field is not needed for non_DEBU builds so remove it. While
we're at i also clean up the interface for is locked asserts to go through
and xfs_iget.c helper with an interface like the xfs_ilock routines to
isolated the XFS codebase from mrlock internals. That way we can kill
mrlock_t entirely once rw_semaphores grow an islocked facility. Also
remove unused flags to the ilock family of functions.

SGI-PV: 976035
SGI-Modid: xfs-linux-melb:xfs-kern:30902a

Signed-off-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Lachlan McIlroy <lachlan@sgi.com>

fs/xfs/linux-2.6/mrlock.h

@@ -20,29 +20,24 @@
 
 #include <linux/rwsem.h>
 
-enum { MR_NONE, MR_ACCESS, MR_UPDATE };
-
 typedef struct {
 	struct rw_semaphore	mr_lock;
+#ifdef DEBUG
 	int			mr_writer;
+#endif
 } mrlock_t;
 
+#ifdef DEBUG
 #define mrinit(mrp, name)	\
 	do { (mrp)->mr_writer = 0; init_rwsem(&(mrp)->mr_lock); } while (0)
+#else
+#define mrinit(mrp, name)	\
+	do { init_rwsem(&(mrp)->mr_lock); } while (0)
+#endif
+
 #define mrlock_init(mrp, t,n,s)	mrinit(mrp, n)
 #define mrfree(mrp)		do { } while (0)
 
-static inline void mraccess(mrlock_t *mrp)
-{
-	down_read(&mrp->mr_lock);
-}
-
-static inline void mrupdate(mrlock_t *mrp)
-{
-	down_write(&mrp->mr_lock);
-	mrp->mr_writer = 1;
-}
-
 static inline void mraccess_nested(mrlock_t *mrp, int subclass)
 {
 	down_read_nested(&mrp->mr_lock, subclass);
@@ -51,10 +46,11 @@ static inline void mraccess_nested(mrlock_t *mrp, int subclass)
 static inline void mrupdate_nested(mrlock_t *mrp, int subclass)
 {
 	down_write_nested(&mrp->mr_lock, subclass);
+#ifdef DEBUG
 	mrp->mr_writer = 1;
+#endif
 }
 
-
 static inline int mrtryaccess(mrlock_t *mrp)
 {
 	return down_read_trylock(&mrp->mr_lock);
@@ -64,39 +60,31 @@ static inline int mrtryupdate(mrlock_t *mrp)
 {
 	if (!down_write_trylock(&mrp->mr_lock))
 		return 0;
+#ifdef DEBUG
 	mrp->mr_writer = 1;
+#endif
 	return 1;
 }
 
-static inline void mrunlock(mrlock_t *mrp)
+static inline void mrunlock_excl(mrlock_t *mrp)
 {
-	if (mrp->mr_writer) {
-		mrp->mr_writer = 0;
-		up_write(&mrp->mr_lock);
-	} else {
-		up_read(&mrp->mr_lock);
-	}
+#ifdef DEBUG
+	mrp->mr_writer = 0;
+#endif
+	up_write(&mrp->mr_lock);
 }
 
-static inline void mrdemote(mrlock_t *mrp)
+static inline void mrunlock_shared(mrlock_t *mrp)
 {
-	mrp->mr_writer = 0;
-	downgrade_write(&mrp->mr_lock);
+	up_read(&mrp->mr_lock);
 }
 
-#ifdef DEBUG
-/*
- * Debug-only routine, without some platform-specific asm code, we can
- * now only answer requests regarding whether we hold the lock for write
- * (reader state is outside our visibility, we only track writer state).
- * Note: means !ismrlocked would give false positives, so don't do that.
- */
-static inline int ismrlocked(mrlock_t *mrp, int type)
+static inline void mrdemote(mrlock_t *mrp)
 {
-	if (mrp && type == MR_UPDATE)
-		return mrp->mr_writer;
-	return 1;
-}
+#ifdef DEBUG
+	mrp->mr_writer = 0;
 #endif
+	downgrade_write(&mrp->mr_lock);
+}
 
 #endif /* __XFS_SUPPORT_MRLOCK_H__ */

fs/xfs/linux-2.6/xfs_lrw.c

@@ -394,7 +394,7 @@ xfs_zero_last_block(
 	int		error = 0;
 	xfs_bmbt_irec_t	imap;
 
-	ASSERT(ismrlocked(&ip->i_lock, MR_UPDATE) != 0);
+	ASSERT(xfs_isilocked(ip, XFS_ILOCK_EXCL));
 
 	zero_offset = XFS_B_FSB_OFFSET(mp, isize);
 	if (zero_offset == 0) {
@@ -425,14 +425,14 @@ xfs_zero_last_block(
 	 * out sync.  We need to drop the ilock while we do this so we
 	 * don't deadlock when the buffer cache calls back to us.
 	 */
-	xfs_iunlock(ip, XFS_ILOCK_EXCL| XFS_EXTSIZE_RD);
+	xfs_iunlock(ip, XFS_ILOCK_EXCL);
 
 	zero_len = mp->m_sb.sb_blocksize - zero_offset;
 	if (isize + zero_len > offset)
 		zero_len = offset - isize;
 	error = xfs_iozero(ip, isize, zero_len);
 
-	xfs_ilock(ip, XFS_ILOCK_EXCL|XFS_EXTSIZE_RD);
+	xfs_ilock(ip, XFS_ILOCK_EXCL);
 	ASSERT(error >= 0);
 	return error;
 }
@@ -465,8 +465,7 @@ xfs_zero_eof(
 	int		error = 0;
 	xfs_bmbt_irec_t	imap;
 
-	ASSERT(ismrlocked(&ip->i_lock, MR_UPDATE));
-	ASSERT(ismrlocked(&ip->i_iolock, MR_UPDATE));
+	ASSERT(xfs_isilocked(ip, XFS_ILOCK_EXCL|XFS_IOLOCK_EXCL));
 	ASSERT(offset > isize);
 
 	/*
@@ -475,8 +474,7 @@ xfs_zero_eof(
 	 */
 	error = xfs_zero_last_block(ip, offset, isize);
 	if (error) {
-		ASSERT(ismrlocked(&ip->i_lock, MR_UPDATE));
-		ASSERT(ismrlocked(&ip->i_iolock, MR_UPDATE));
+		ASSERT(xfs_isilocked(ip, XFS_ILOCK_EXCL|XFS_IOLOCK_EXCL));
 		return error;
 	}
 
@@ -507,8 +505,7 @@ xfs_zero_eof(
 		error = xfs_bmapi(NULL, ip, start_zero_fsb, zero_count_fsb,
 				  0, NULL, 0, &imap, &nimaps, NULL, NULL);
 		if (error) {
-			ASSERT(ismrlocked(&ip->i_lock, MR_UPDATE));
-			ASSERT(ismrlocked(&ip->i_iolock, MR_UPDATE));
+			ASSERT(xfs_isilocked(ip, XFS_ILOCK_EXCL|XFS_IOLOCK_EXCL));
 			return error;
 		}
 		ASSERT(nimaps > 0);
@@ -532,7 +529,7 @@ xfs_zero_eof(
 		 * Drop the inode lock while we're doing the I/O.
 		 * We'll still have the iolock to protect us.
 		 */
-		xfs_iunlock(ip, XFS_ILOCK_EXCL|XFS_EXTSIZE_RD);
+		xfs_iunlock(ip, XFS_ILOCK_EXCL);
 
 		zero_off = XFS_FSB_TO_B(mp, start_zero_fsb);
 		zero_len = XFS_FSB_TO_B(mp, imap.br_blockcount);
@@ -548,13 +545,13 @@ xfs_zero_eof(
 		start_zero_fsb = imap.br_startoff + imap.br_blockcount;
 		ASSERT(start_zero_fsb <= (end_zero_fsb + 1));
 
-		xfs_ilock(ip, XFS_ILOCK_EXCL|XFS_EXTSIZE_RD);
+		xfs_ilock(ip, XFS_ILOCK_EXCL);
 	}
 
 	return 0;
 
 out_lock:
-	xfs_ilock(ip, XFS_ILOCK_EXCL|XFS_EXTSIZE_RD);
+	xfs_ilock(ip, XFS_ILOCK_EXCL);
 	ASSERT(error >= 0);
 	return error;
 }

fs/xfs/quota/xfs_dquot.c

@@ -933,7 +933,7 @@ xfs_qm_dqget(
 	       type == XFS_DQ_PROJ ||
 	       type == XFS_DQ_GROUP);
 	if (ip) {
-		ASSERT(XFS_ISLOCKED_INODE_EXCL(ip));
+		ASSERT(xfs_isilocked(ip, XFS_ILOCK_EXCL));
 		if (type == XFS_DQ_USER)
 			ASSERT(ip->i_udquot == NULL);
 		else
@@ -1088,7 +1088,7 @@ xfs_qm_dqget(
 	xfs_qm_mplist_unlock(mp);
 	XFS_DQ_HASH_UNLOCK(h);
  dqret:
-	ASSERT((ip == NULL) || XFS_ISLOCKED_INODE_EXCL(ip));
+	ASSERT((ip == NULL) || xfs_isilocked(ip, XFS_ILOCK_EXCL));
 	xfs_dqtrace_entry(dqp, "DQGET DONE");
 	*O_dqpp = dqp;
 	return (0);

fs/xfs/quota/xfs_qm.c

@@ -670,7 +670,7 @@ xfs_qm_dqattach_one(
 	xfs_dquot_t	*dqp;
 	int		error;
 
-	ASSERT(XFS_ISLOCKED_INODE_EXCL(ip));
+	ASSERT(xfs_isilocked(ip, XFS_ILOCK_EXCL));
 	error = 0;
 	/*
 	 * See if we already have it in the inode itself. IO_idqpp is
@@ -874,7 +874,7 @@ xfs_qm_dqattach(
 		return 0;
 
 	ASSERT((flags & XFS_QMOPT_ILOCKED) == 0 ||
-	       XFS_ISLOCKED_INODE_EXCL(ip));
+	       xfs_isilocked(ip, XFS_ILOCK_EXCL));
 
 	if (! (flags & XFS_QMOPT_ILOCKED))
 		xfs_ilock(ip, XFS_ILOCK_EXCL);
@@ -888,7 +888,8 @@ xfs_qm_dqattach(
 			goto done;
 		nquotas++;
 	}
-	ASSERT(XFS_ISLOCKED_INODE_EXCL(ip));
+
+	ASSERT(xfs_isilocked(ip, XFS_ILOCK_EXCL));
 	if (XFS_IS_OQUOTA_ON(mp)) {
 		error = XFS_IS_GQUOTA_ON(mp) ?
 			xfs_qm_dqattach_one(ip, ip->i_d.di_gid, XFS_DQ_GROUP,
@@ -913,7 +914,7 @@ xfs_qm_dqattach(
 	 * This WON'T, in general, result in a thrash.
 	 */
 	if (nquotas == 2) {
-		ASSERT(XFS_ISLOCKED_INODE_EXCL(ip));
+		ASSERT(xfs_isilocked(ip, XFS_ILOCK_EXCL));
 		ASSERT(ip->i_udquot);
 		ASSERT(ip->i_gdquot);
 
@@ -956,7 +957,7 @@ xfs_qm_dqattach(
 
 #ifdef QUOTADEBUG
 	else
-		ASSERT(XFS_ISLOCKED_INODE_EXCL(ip));
+		ASSERT(xfs_isilocked(ip, XFS_ILOCK_EXCL));
 #endif
 	return error;
 }
@@ -1291,7 +1292,7 @@ xfs_qm_dqget_noattach(
 	xfs_mount_t	*mp;
 	xfs_dquot_t	*udqp, *gdqp;
 
-	ASSERT(XFS_ISLOCKED_INODE_EXCL(ip));
+	ASSERT(xfs_isilocked(ip, XFS_ILOCK_EXCL));
 	mp = ip->i_mount;
 	udqp = NULL;
 	gdqp = NULL;
@@ -1392,7 +1393,7 @@ xfs_qm_qino_alloc(
 	 * Keep an extra reference to this quota inode. This inode is
 	 * locked exclusively and joined to the transaction already.
 	 */
-	ASSERT(XFS_ISLOCKED_INODE_EXCL(*ip));
+	ASSERT(xfs_isilocked(*ip, XFS_ILOCK_EXCL));
 	VN_HOLD(XFS_ITOV((*ip)));
 
 	/*
@@ -2557,7 +2558,7 @@ xfs_qm_vop_chown(
 	uint		bfield = XFS_IS_REALTIME_INODE(ip) ?
 				 XFS_TRANS_DQ_RTBCOUNT : XFS_TRANS_DQ_BCOUNT;
 
-	ASSERT(XFS_ISLOCKED_INODE_EXCL(ip));
+	ASSERT(xfs_isilocked(ip, XFS_ILOCK_EXCL));
 	ASSERT(XFS_IS_QUOTA_RUNNING(ip->i_mount));
 
 	/* old dquot */
@@ -2601,7 +2602,7 @@ xfs_qm_vop_chown_reserve(
 	uint		delblks, blkflags, prjflags = 0;
 	xfs_dquot_t	*unresudq, *unresgdq, *delblksudq, *delblksgdq;
 
-	ASSERT(XFS_ISLOCKED_INODE(ip));
+	ASSERT(xfs_isilocked(ip, XFS_ILOCK_EXCL|XFS_ILOCK_SHARED));
 	mp = ip->i_mount;
 	ASSERT(XFS_IS_QUOTA_RUNNING(mp));
 
@@ -2711,7 +2712,7 @@ xfs_qm_vop_dqattach_and_dqmod_newinode(
 	if (!XFS_IS_QUOTA_ON(tp->t_mountp))
 		return;
 
-	ASSERT(XFS_ISLOCKED_INODE_EXCL(ip));
+	ASSERT(xfs_isilocked(ip, XFS_ILOCK_EXCL));
 	ASSERT(XFS_IS_QUOTA_RUNNING(tp->t_mountp));
 
 	if (udqp) {

fs/xfs/quota/xfs_quota_priv.h

@@ -27,11 +27,6 @@
 /* Number of dquots that fit in to a dquot block */
 #define XFS_QM_DQPERBLK(mp)	((mp)->m_quotainfo->qi_dqperchunk)
 
-#define XFS_ISLOCKED_INODE(ip)		(ismrlocked(&(ip)->i_lock, \
-					    MR_UPDATE | MR_ACCESS) != 0)
-#define XFS_ISLOCKED_INODE_EXCL(ip)	(ismrlocked(&(ip)->i_lock, \
-					    MR_UPDATE) != 0)
-
 #define XFS_DQ_IS_ADDEDTO_TRX(t, d)	((d)->q_transp == (t))
 
 #define XFS_QI_MPLRECLAIMS(mp)	((mp)->m_quotainfo->qi_dqreclaims)

fs/xfs/quota/xfs_trans_dquot.c

@@ -834,7 +834,7 @@ xfs_trans_reserve_quota_nblks(
 	ASSERT(ip->i_ino != mp->m_sb.sb_uquotino);
 	ASSERT(ip->i_ino != mp->m_sb.sb_gquotino);
 
-	ASSERT(XFS_ISLOCKED_INODE_EXCL(ip));
+	ASSERT(xfs_isilocked(ip, XFS_ILOCK_EXCL));
 	ASSERT(XFS_IS_QUOTA_RUNNING(ip->i_mount));
 	ASSERT((flags & ~(XFS_QMOPT_FORCE_RES | XFS_QMOPT_ENOSPC)) ==
 				XFS_TRANS_DQ_RES_RTBLKS ||

fs/xfs/xfs_bmap.c

@@ -4074,7 +4074,6 @@ xfs_bmap_add_attrfork(
 error2:
 	xfs_bmap_cancel(&flist);
 error1:
-	ASSERT(ismrlocked(&ip->i_lock,MR_UPDATE));
 	xfs_iunlock(ip, XFS_ILOCK_EXCL);
 error0:
 	xfs_trans_cancel(tp, XFS_TRANS_RELEASE_LOG_RES|XFS_TRANS_ABORT);