[PATCH V3 05/12] xfs: Introduce xfs_dfork_nextents() helper

[Chandan Babu R <chandan.babu@oracle.com>]

This commit replaces the macro XFS_DFORK_NEXTENTS() with the helper function
xfs_dfork_nextents(). As of this commit, xfs_dfork_nextents() returns the same
value as XFS_DFORK_NEXTENTS(). A future commit which extends inode's extent
counter fields will add more logic to this helper.

This commit also replaces direct accesses to xfs_dinode->di_[a]nextents
with calls to xfs_dfork_nextents().

No functional changes have been made.

Signed-off-by: Chandan Babu R <chandan.babu@oracle.com>
---
 fs/xfs/libxfs/xfs_format.h     | 28 +++++++++++++++++++++----
 fs/xfs/libxfs/xfs_inode_buf.c  | 16 +++++++++-----
 fs/xfs/libxfs/xfs_inode_fork.c | 10 +++++----
 fs/xfs/scrub/inode.c           | 18 +++++++++-------
 fs/xfs/scrub/inode_repair.c    | 38 +++++++++++++++++++++-------------
 5 files changed, 75 insertions(+), 35 deletions(-)

diff --git a/fs/xfs/libxfs/xfs_format.h b/fs/xfs/libxfs/xfs_format.h
index ed8a5354bcbf..b4638052801f 100644
--- a/fs/xfs/libxfs/xfs_format.h
+++ b/fs/xfs/libxfs/xfs_format.h
@@ -930,10 +930,30 @@ enum xfs_dinode_fmt {
 	((w) == XFS_DATA_FORK ? \
 		(dip)->di_format : \
 		(dip)->di_aformat)
-#define XFS_DFORK_NEXTENTS(dip,w) \
-	((w) == XFS_DATA_FORK ? \
-		be32_to_cpu((dip)->di_nextents) : \
-		be16_to_cpu((dip)->di_anextents))
+
+static inline xfs_extnum_t
+xfs_dfork_nextents(
+	struct xfs_dinode	*dip,
+	int			whichfork)
+{
+	xfs_extnum_t		nextents = 0;
+
+	switch (whichfork) {
+	case XFS_DATA_FORK:
+		nextents = be32_to_cpu(dip->di_nextents);
+		break;
+
+	case XFS_ATTR_FORK:
+		nextents = be16_to_cpu(dip->di_anextents);
+		break;
+
+	default:
+		ASSERT(0);
+		break;
+	}
+
+	return nextents;
+}
 
 /*
  * For block and character special files the 32bit dev_t is stored at the
diff --git a/fs/xfs/libxfs/xfs_inode_buf.c b/fs/xfs/libxfs/xfs_inode_buf.c
index ea4469b5114e..176c98798aa4 100644
--- a/fs/xfs/libxfs/xfs_inode_buf.c
+++ b/fs/xfs/libxfs/xfs_inode_buf.c
@@ -342,9 +342,11 @@ xfs_dinode_verify_fork(
 	struct xfs_mount	*mp,
 	int			whichfork)
 {
-	xfs_extnum_t		di_nextents = XFS_DFORK_NEXTENTS(dip, whichfork);
+	xfs_extnum_t		di_nextents;
 	xfs_extnum_t		max_extents;
 
+	di_nextents = xfs_dfork_nextents(dip, whichfork);
+
 	switch (XFS_DFORK_FORMAT(dip, whichfork)) {
 	case XFS_DINODE_FMT_LOCAL:
 		/*
@@ -474,6 +476,8 @@ xfs_dinode_verify(
 	uint16_t		flags;
 	uint64_t		flags2;
 	uint64_t		di_size;
+	xfs_extnum_t            nextents;
+	xfs_rfsblock_t		nblocks;
 
 	if (dip->di_magic != cpu_to_be16(XFS_DINODE_MAGIC))
 		return __this_address;
@@ -504,10 +508,12 @@ xfs_dinode_verify(
 	if ((S_ISLNK(mode) || S_ISDIR(mode)) && di_size == 0)
 		return __this_address;
 
+	nextents = xfs_dfork_nextents(dip, XFS_DATA_FORK);
+	nextents += xfs_dfork_nextents(dip, XFS_ATTR_FORK);
+	nblocks = be64_to_cpu(dip->di_nblocks);
+
 	/* Fork checks carried over from xfs_iformat_fork */
-	if (mode &&
-	    be32_to_cpu(dip->di_nextents) + be16_to_cpu(dip->di_anextents) >
-			be64_to_cpu(dip->di_nblocks))
+	if (mode && nextents > nblocks)
 		return __this_address;
 
 	if (mode && XFS_DFORK_BOFF(dip) > mp->m_sb.sb_inodesize)
@@ -564,7 +570,7 @@ xfs_dinode_verify(
 		default:
 			return __this_address;
 		}
-		if (dip->di_anextents)
+		if (xfs_dfork_nextents(dip, XFS_ATTR_FORK))
 			return __this_address;
 	}
 
diff --git a/fs/xfs/libxfs/xfs_inode_fork.c b/fs/xfs/libxfs/xfs_inode_fork.c
index e7bb3ba22912..7d1efccfea59 100644
--- a/fs/xfs/libxfs/xfs_inode_fork.c
+++ b/fs/xfs/libxfs/xfs_inode_fork.c
@@ -107,7 +107,7 @@ xfs_iformat_extents(
 	struct xfs_mount	*mp = ip->i_mount;
 	struct xfs_ifork	*ifp = XFS_IFORK_PTR(ip, whichfork);
 	int			state = xfs_bmap_fork_to_state(whichfork);
-	xfs_extnum_t		nex = XFS_DFORK_NEXTENTS(dip, whichfork);
+	xfs_extnum_t		nex = xfs_dfork_nextents(dip, whichfork);
 	int			size = nex * sizeof(xfs_bmbt_rec_t);
 	struct xfs_iext_cursor	icur;
 	struct xfs_bmbt_rec	*dp;
@@ -234,7 +234,7 @@ xfs_iformat_data_fork(
 	 * depend on it.
 	 */
 	ip->i_df.if_format = dip->di_format;
-	ip->i_df.if_nextents = be32_to_cpu(dip->di_nextents);
+	ip->i_df.if_nextents = xfs_dfork_nextents(dip, XFS_DATA_FORK);
 
 	switch (inode->i_mode & S_IFMT) {
 	case S_IFIFO:
@@ -301,14 +301,16 @@ xfs_iformat_attr_fork(
 	struct xfs_inode	*ip,
 	struct xfs_dinode	*dip)
 {
+	xfs_extnum_t		naextents;
 	int			error = 0;
 
+	naextents = xfs_dfork_nextents(dip, XFS_ATTR_FORK);
+
 	/*
 	 * Initialize the extent count early, as the per-format routines may
 	 * depend on it.
 	 */
-	ip->i_afp = xfs_ifork_alloc(dip->di_aformat,
-				be16_to_cpu(dip->di_anextents));
+	ip->i_afp = xfs_ifork_alloc(dip->di_aformat, naextents);
 
 	switch (ip->i_afp->if_format) {
 	case XFS_DINODE_FMT_LOCAL:
diff --git a/fs/xfs/scrub/inode.c b/fs/xfs/scrub/inode.c
index 87925761e174..4177b85c941d 100644
--- a/fs/xfs/scrub/inode.c
+++ b/fs/xfs/scrub/inode.c
@@ -233,6 +233,7 @@ xchk_dinode(
 	unsigned long long	isize;
 	uint64_t		flags2;
 	xfs_extnum_t		nextents;
+	xfs_extnum_t		naextents;
 	prid_t			prid;
 	uint16_t		flags;
 	uint16_t		mode;
@@ -391,7 +392,7 @@ xchk_dinode(
 	xchk_inode_extsize(sc, dip, ino, mode, flags);
 
 	/* di_nextents */
-	nextents = be32_to_cpu(dip->di_nextents);
+	nextents = xfs_dfork_nextents(dip, XFS_DATA_FORK);
 	fork_recs =  XFS_DFORK_DSIZE(dip, mp) / sizeof(struct xfs_bmbt_rec);
 	switch (dip->di_format) {
 	case XFS_DINODE_FMT_EXTENTS:
@@ -408,10 +409,12 @@ xchk_dinode(
 		break;
 	}
 
+	naextents = xfs_dfork_nextents(dip, XFS_ATTR_FORK);
+
 	/* di_forkoff */
 	if (XFS_DFORK_APTR(dip) >= (char *)dip + mp->m_sb.sb_inodesize)
 		xchk_ino_set_corrupt(sc, ino);
-	if (dip->di_anextents != 0 && dip->di_forkoff == 0)
+	if (naextents != 0 && dip->di_forkoff == 0)
 		xchk_ino_set_corrupt(sc, ino);
 	if (dip->di_forkoff == 0 && dip->di_aformat != XFS_DINODE_FMT_EXTENTS)
 		xchk_ino_set_corrupt(sc, ino);
@@ -423,19 +426,18 @@ xchk_dinode(
 		xchk_ino_set_corrupt(sc, ino);
 
 	/* di_anextents */
-	nextents = be16_to_cpu(dip->di_anextents);
 	fork_recs =  XFS_DFORK_ASIZE(dip, mp) / sizeof(struct xfs_bmbt_rec);
 	switch (dip->di_aformat) {
 	case XFS_DINODE_FMT_EXTENTS:
-		if (nextents > fork_recs)
+		if (naextents > fork_recs)
 			xchk_ino_set_corrupt(sc, ino);
 		break;
 	case XFS_DINODE_FMT_BTREE:
-		if (nextents <= fork_recs)
+		if (naextents <= fork_recs)
 			xchk_ino_set_corrupt(sc, ino);
 		break;
 	default:
-		if (nextents != 0)
+		if (naextents != 0)
 			xchk_ino_set_corrupt(sc, ino);
 	}
 
@@ -513,14 +515,14 @@ xchk_inode_xref_bmap(
 			&nextents, &count);
 	if (!xchk_should_check_xref(sc, &error, NULL))
 		return;
-	if (nextents < be32_to_cpu(dip->di_nextents))
+	if (nextents < xfs_dfork_nextents(dip, XFS_DATA_FORK))
 		xchk_ino_xref_set_corrupt(sc, sc->ip->i_ino);
 
 	error = xfs_bmap_count_blocks(sc->tp, sc->ip, XFS_ATTR_FORK,
 			&nextents, &acount);
 	if (!xchk_should_check_xref(sc, &error, NULL))
 		return;
-	if (nextents != be16_to_cpu(dip->di_anextents))
+	if (nextents != xfs_dfork_nextents(dip, XFS_ATTR_FORK))
 		xchk_ino_xref_set_corrupt(sc, sc->ip->i_ino);
 
 	/* Check nblocks against the inode. */
diff --git a/fs/xfs/scrub/inode_repair.c b/fs/xfs/scrub/inode_repair.c
index bebc1fd33667..ec8360b3b13b 100644
--- a/fs/xfs/scrub/inode_repair.c
+++ b/fs/xfs/scrub/inode_repair.c
@@ -606,7 +606,7 @@ xrep_dinode_bad_extents_fork(
 	xfs_extnum_t		nex;
 	int			fork_size;
 
-	nex = XFS_DFORK_NEXTENTS(dip, whichfork);
+	nex = xfs_dfork_nextents(dip, whichfork);
 	fork_size = nex * sizeof(struct xfs_bmbt_rec);
 	if (fork_size < 0 || fork_size > dfork_size)
 		return true;
@@ -640,7 +640,7 @@ xrep_dinode_bad_btree_fork(
 	int			nrecs;
 	int			level;
 
-	if (XFS_DFORK_NEXTENTS(dip, whichfork) <=
+	if (xfs_dfork_nextents(dip, whichfork) <=
 			dfork_size / sizeof(struct xfs_bmbt_rec))
 		return true;
 
@@ -835,12 +835,16 @@ xrep_dinode_ensure_forkoff(
 	struct xrep_dinode_stats	*dis)
 {
 	struct xfs_bmdr_block		*bmdr;
+	xfs_extnum_t			anextents, dnextents;
 	size_t				bmdr_minsz = xfs_bmdr_space_calc(1);
 	unsigned int			lit_sz = XFS_LITINO(sc->mp);
 	unsigned int			afork_min, dfork_min;
 
 	trace_xrep_dinode_ensure_forkoff(sc, dip);
 
+	dnextents = xfs_dfork_nextents(dip, XFS_DATA_FORK);
+	anextents = xfs_dfork_nextents(dip, XFS_ATTR_FORK);
+
 	/*
 	 * Before calling this function, xrep_dinode_core ensured that both
 	 * forks actually fit inside their respective literal areas.  If this
@@ -861,15 +865,14 @@ xrep_dinode_ensure_forkoff(
 		afork_min = XFS_DFORK_SIZE(dip, sc->mp, XFS_ATTR_FORK);
 		break;
 	case XFS_DINODE_FMT_EXTENTS:
-		if (dip->di_anextents) {
+		if (anextents) {
 			/*
 			 * We must maintain sufficient space to hold the entire
 			 * extent map array in the data fork.  Note that we
 			 * previously zapped the fork if it had no chance of
 			 * fitting in the inode.
 			 */
-			afork_min = sizeof(struct xfs_bmbt_rec) *
-						be16_to_cpu(dip->di_anextents);
+			afork_min = sizeof(struct xfs_bmbt_rec) * anextents;
 		} else if (dis->attr_extents > 0) {
 			/*
 			 * The attr fork thinks it has zero extents, but we
@@ -912,15 +915,14 @@ xrep_dinode_ensure_forkoff(
 		dfork_min = be64_to_cpu(dip->di_size);
 		break;
 	case XFS_DINODE_FMT_EXTENTS:
-		if (dip->di_nextents) {
+		if (dnextents) {
 			/*
 			 * We must maintain sufficient space to hold the entire
 			 * extent map array in the data fork.  Note that we
 			 * previously zapped the fork if it had no chance of
 			 * fitting in the inode.
 			 */
-			dfork_min = sizeof(struct xfs_bmbt_rec) *
-						be32_to_cpu(dip->di_nextents);
+			dfork_min = sizeof(struct xfs_bmbt_rec) * dnextents;
 		} else if (dis->data_extents > 0 || dis->rt_extents > 0) {
 			/*
 			 * The data fork thinks it has zero extents, but we
@@ -960,7 +962,7 @@ xrep_dinode_ensure_forkoff(
 	 * recovery fork, move the attr fork up.
 	 */
 	if (dip->di_format == XFS_DINODE_FMT_EXTENTS &&
-	    dip->di_nextents == 0 &&
+	    dnextents == 0 &&
 	    (dis->data_extents > 0 || dis->rt_extents > 0) &&
 	    bmdr_minsz > XFS_DFORK_DSIZE(dip, sc->mp)) {
 		if (bmdr_minsz + afork_min > lit_sz) {
@@ -986,7 +988,7 @@ xrep_dinode_ensure_forkoff(
 	 * recovery fork, move the attr fork down.
 	 */
 	if (dip->di_aformat == XFS_DINODE_FMT_EXTENTS &&
-	    dip->di_anextents == 0 &&
+	    anextents == 0 &&
 	    dis->attr_extents > 0 &&
 	    bmdr_minsz > XFS_DFORK_ASIZE(dip, sc->mp)) {
 		if (dip->di_format == XFS_DINODE_FMT_BTREE) {
@@ -1023,6 +1025,9 @@ xrep_dinode_zap_forks(
 	struct xfs_dinode		*dip,
 	struct xrep_dinode_stats	*dis)
 {
+	xfs_rfsblock_t			nblocks;
+	xfs_extnum_t			nextents;
+	xfs_extnum_t			naextents;
 	uint16_t			mode;
 	bool				zap_datafork = false;
 	bool				zap_attrfork = false;
@@ -1032,12 +1037,17 @@ xrep_dinode_zap_forks(
 	mode = be16_to_cpu(dip->di_mode);
 
 	/* Inode counters don't make sense? */
-	if (be32_to_cpu(dip->di_nextents) > be64_to_cpu(dip->di_nblocks))
+	nblocks = be64_to_cpu(dip->di_nblocks);
+
+	nextents = xfs_dfork_nextents(dip, XFS_DATA_FORK);
+	if (nextents > nblocks)
 		zap_datafork = true;
-	if (be16_to_cpu(dip->di_anextents) > be64_to_cpu(dip->di_nblocks))
+
+	naextents = xfs_dfork_nextents(dip, XFS_ATTR_FORK);
+	if (naextents > nblocks)
 		zap_attrfork = true;
-	if (be32_to_cpu(dip->di_nextents) + be16_to_cpu(dip->di_anextents) >
-			be64_to_cpu(dip->di_nblocks))
+
+	if (nextents + naextents > nblocks)
 		zap_datafork = zap_attrfork = true;
 
 	if (!zap_datafork)
-- 
2.30.2