xfs: update for 4.1-rc6

Changes in this update:
 o regression fix for new rename whiteout code
 o regression fixes for new superblock generic per-cpu counter code
 o fix for incorrect error return sign introduced in 3.17
 o metadata corruption fixes that need to go back to -stable kernels
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Merge tag 'xfs-for-linus-4.1-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/dgc/linux-xfs

Pull xfs fixes from Dave Chinner:
 "This is a little larger than I'd like late in the release cycle, but
  all the fixes are for regressions introduced in the 4.1-rc1 merge, or
  are needed back in -stable kernels fairly quickly as they are
  filesystem corruption or userspace visible correctness issues.

  Changes in this update:

   - regression fix for new rename whiteout code

   - regression fixes for new superblock generic per-cpu counter code

   - fix for incorrect error return sign introduced in 3.17

   - metadata corruption fixes that need to go back to -stable kernels"

* tag 'xfs-for-linus-4.1-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/dgc/linux-xfs:
  xfs: fix broken i_nlink accounting for whiteout tmpfile inode
  xfs: xfs_iozero can return positive errno
  xfs: xfs_attr_inactive leaves inconsistent attr fork state behind
  xfs: extent size hints can round up extents past MAXEXTLEN
  xfs: inode and free block counters need to use __percpu_counter_compare
  percpu_counter: batch size aware __percpu_counter_compare()
  xfs: use percpu_counter_read_positive for mp->m_icount

fs/xfs/libxfs/xfs_attr_leaf.c

@@ -574,8 +574,8 @@ xfs_attr_shortform_add(xfs_da_args_t *args, int forkoff)
  * After the last attribute is removed revert to original inode format,
  * making all literal area available to the data fork once more.
  */
-STATIC void
+void
-xfs_attr_fork_reset(
+xfs_attr_fork_remove(
 	struct xfs_inode	*ip,
 	struct xfs_trans	*tp)
 {
@@ -641,7 +641,7 @@ xfs_attr_shortform_remove(xfs_da_args_t *args)
 	    (mp->m_flags & XFS_MOUNT_ATTR2) &&
 	    (dp->i_d.di_format != XFS_DINODE_FMT_BTREE) &&
 	    !(args->op_flags & XFS_DA_OP_ADDNAME)) {
-		xfs_attr_fork_reset(dp, args->trans);
+		xfs_attr_fork_remove(dp, args->trans);
 	} else {
 		xfs_idata_realloc(dp, -size, XFS_ATTR_FORK);
 		dp->i_d.di_forkoff = xfs_attr_shortform_bytesfit(dp, totsize);
@@ -905,7 +905,7 @@ xfs_attr3_leaf_to_shortform(
 	if (forkoff == -1) {
 		ASSERT(dp->i_mount->m_flags & XFS_MOUNT_ATTR2);
 		ASSERT(dp->i_d.di_format != XFS_DINODE_FMT_BTREE);
-		xfs_attr_fork_reset(dp, args->trans);
+		xfs_attr_fork_remove(dp, args->trans);
 		goto out;
 	}
 

fs/xfs/libxfs/xfs_attr_leaf.h

@@ -53,7 +53,7 @@ int	xfs_attr_shortform_remove(struct xfs_da_args *args);
 int	xfs_attr_shortform_list(struct xfs_attr_list_context *context);
 int	xfs_attr_shortform_allfit(struct xfs_buf *bp, struct xfs_inode *dp);
 int	xfs_attr_shortform_bytesfit(xfs_inode_t *dp, int bytes);
-
+void	xfs_attr_fork_remove(struct xfs_inode *ip, struct xfs_trans *tp);
 
 /*
  * Internal routines when attribute fork size == XFS_LBSIZE(mp).

fs/xfs/libxfs/xfs_bmap.c

@@ -3224,12 +3224,24 @@ xfs_bmap_extsize_align(
 		align_alen += temp;
 		align_off -= temp;
 	}
-	/*
+
-	 * Same adjustment for the end of the requested area.
+	/* Same adjustment for the end of the requested area. */
-	 */
+	temp = (align_alen % extsz);
-	if ((temp = (align_alen % extsz))) {
+	if (temp)
 		align_alen += extsz - temp;
-	}
+
+	/*
+	 * For large extent hint sizes, the aligned extent might be larger than
+	 * MAXEXTLEN. In that case, reduce the size by an extsz so that it pulls
+	 * the length back under MAXEXTLEN. The outer allocation loops handle
+	 * short allocation just fine, so it is safe to do this. We only want to
+	 * do it when we are forced to, though, because it means more allocation
+	 * operations are required.
+	 */
+	while (align_alen > MAXEXTLEN)
+		align_alen -= extsz;
+	ASSERT(align_alen <= MAXEXTLEN);
+
 	/*
 	 * If the previous block overlaps with this proposed allocation
 	 * then move the start forward without adjusting the length.
@@ -3318,7 +3330,9 @@ xfs_bmap_extsize_align(
 			return -EINVAL;
 	} else {
 		ASSERT(orig_off >= align_off);
-		ASSERT(orig_end <= align_off + align_alen);
+		/* see MAXEXTLEN handling above */
+		ASSERT(orig_end <= align_off + align_alen ||
+		       align_alen + extsz > MAXEXTLEN);
 	}
 
 #ifdef DEBUG
@@ -4099,13 +4113,6 @@ xfs_bmapi_reserve_delalloc(
 	/* Figure out the extent size, adjust alen */
 	extsz = xfs_get_extsz_hint(ip);
 	if (extsz) {
-		/*
-		 * Make sure we don't exceed a single extent length when we
-		 * align the extent by reducing length we are going to
-		 * allocate by the maximum amount extent size aligment may
-		 * require.
-		 */
-		alen = XFS_FILBLKS_MIN(len, MAXEXTLEN - (2 * extsz - 1));
 		error = xfs_bmap_extsize_align(mp, got, prev, extsz, rt, eof,
 					       1, 0, &aoff, &alen);
 		ASSERT(!error);

fs/xfs/libxfs/xfs_ialloc.c

@@ -376,7 +376,7 @@ xfs_ialloc_ag_alloc(
 	 */
 	newlen = args.mp->m_ialloc_inos;
 	if (args.mp->m_maxicount &&
-	    percpu_counter_read(&args.mp->m_icount) + newlen >
+	    percpu_counter_read_positive(&args.mp->m_icount) + newlen >
 							args.mp->m_maxicount)
 		return -ENOSPC;
 	args.minlen = args.maxlen = args.mp->m_ialloc_blks;
@@ -1339,10 +1339,13 @@ xfs_dialloc(
 	 * If we have already hit the ceiling of inode blocks then clear
 	 * okalloc so we scan all available agi structures for a free
 	 * inode.
+	 *
+	 * Read rough value of mp->m_icount by percpu_counter_read_positive,
+	 * which will sacrifice the preciseness but improve the performance.
 	 */
 	if (mp->m_maxicount &&
-	    percpu_counter_read(&mp->m_icount) + mp->m_ialloc_inos >
+	    percpu_counter_read_positive(&mp->m_icount) + mp->m_ialloc_inos
-							mp->m_maxicount) {
+							> mp->m_maxicount) {
 		noroom = 1;
 		okalloc = 0;
 	}

fs/xfs/xfs_attr_inactive.c

@@ -380,23 +380,31 @@ xfs_attr3_root_inactive(
 	return error;
 }
 
+/*
+ * xfs_attr_inactive kills all traces of an attribute fork on an inode. It
+ * removes both the on-disk and in-memory inode fork. Note that this also has to
+ * handle the condition of inodes without attributes but with an attribute fork
+ * configured, so we can't use xfs_inode_hasattr() here.
+ *
+ * The in-memory attribute fork is removed even on error.
+ */
 int
-xfs_attr_inactive(xfs_inode_t *dp)
+xfs_attr_inactive(
+	struct xfs_inode	*dp)
 {
-	xfs_trans_t *trans;
+	struct xfs_trans	*trans;
-	xfs_mount_t *mp;
+	struct xfs_mount	*mp;
-	int error;
+	int			cancel_flags = 0;
+	int			lock_mode = XFS_ILOCK_SHARED;
+	int			error = 0;
 
 	mp = dp->i_mount;
 	ASSERT(! XFS_NOT_DQATTACHED(mp, dp));
 
-	xfs_ilock(dp, XFS_ILOCK_SHARED);
+	xfs_ilock(dp, lock_mode);
-	if (!xfs_inode_hasattr(dp) ||
+	if (!XFS_IFORK_Q(dp))
-	    dp->i_d.di_aformat == XFS_DINODE_FMT_LOCAL) {
+		goto out_destroy_fork;
-		xfs_iunlock(dp, XFS_ILOCK_SHARED);
+	xfs_iunlock(dp, lock_mode);
-		return 0;
-	}
-	xfs_iunlock(dp, XFS_ILOCK_SHARED);
 
 	/*
 	 * Start our first transaction of the day.
@@ -408,13 +416,18 @@ xfs_attr_inactive(xfs_inode_t *dp)
 	 * the inode in every transaction to let it float upward through
 	 * the log.
 	 */
+	lock_mode = 0;
 	trans = xfs_trans_alloc(mp, XFS_TRANS_ATTRINVAL);
 	error = xfs_trans_reserve(trans, &M_RES(mp)->tr_attrinval, 0, 0);
-	if (error) {
+	if (error)
-		xfs_trans_cancel(trans, 0);
+		goto out_cancel;
-		return error;
+
-	}
+	lock_mode = XFS_ILOCK_EXCL;
-	xfs_ilock(dp, XFS_ILOCK_EXCL);
+	cancel_flags = XFS_TRANS_RELEASE_LOG_RES | XFS_TRANS_ABORT;
+	xfs_ilock(dp, lock_mode);
+
+	if (!XFS_IFORK_Q(dp))
+		goto out_cancel;
 
 	/*
 	 * No need to make quota reservations here. We expect to release some
@@ -422,29 +435,31 @@ xfs_attr_inactive(xfs_inode_t *dp)
 	 */
 	xfs_trans_ijoin(trans, dp, 0);
 
-	/*
+	/* invalidate and truncate the attribute fork extents */
-	 * Decide on what work routines to call based on the inode size.
+	if (dp->i_d.di_aformat != XFS_DINODE_FMT_LOCAL) {
-	 */
-	if (!xfs_inode_hasattr(dp) ||
-	    dp->i_d.di_aformat == XFS_DINODE_FMT_LOCAL) {
-		error = 0;
-		goto out;
-	}
 		error = xfs_attr3_root_inactive(&trans, dp);
 		if (error)
-		goto out;
+			goto out_cancel;
 
 		error = xfs_itruncate_extents(&trans, dp, XFS_ATTR_FORK, 0);
 		if (error)
-		goto out;
+			goto out_cancel;
+	}
+
+	/* Reset the attribute fork - this also destroys the in-core fork */
+	xfs_attr_fork_remove(dp, trans);
 
 	error = xfs_trans_commit(trans, XFS_TRANS_RELEASE_LOG_RES);
-	xfs_iunlock(dp, XFS_ILOCK_EXCL);
+	xfs_iunlock(dp, lock_mode);
-
 	return error;
 
-out:
+out_cancel:
-	xfs_trans_cancel(trans, XFS_TRANS_RELEASE_LOG_RES|XFS_TRANS_ABORT);
+	xfs_trans_cancel(trans, cancel_flags);
-	xfs_iunlock(dp, XFS_ILOCK_EXCL);
+out_destroy_fork:
+	/* kill the in-core attr fork before we drop the inode lock */
+	if (dp->i_afp)
+		xfs_idestroy_fork(dp, XFS_ATTR_FORK);
+	if (lock_mode)
+		xfs_iunlock(dp, lock_mode);
 	return error;
 }

fs/xfs/xfs_file.c

@@ -124,7 +124,7 @@ xfs_iozero(
 		status = 0;
 	} while (count);
 
-	return (-status);
+	return status;
 }
 
 int

fs/xfs/xfs_inode.c

@@ -1946,21 +1946,17 @@ xfs_inactive(
 	/*
 	 * If there are attributes associated with the file then blow them away
 	 * now.  The code calls a routine that recursively deconstructs the
-	 * attribute fork.  We need to just commit the current transaction
+	 * attribute fork. If also blows away the in-core attribute fork.
-	 * because we can't use it for xfs_attr_inactive().
 	 */
-	if (ip->i_d.di_anextents > 0) {
+	if (XFS_IFORK_Q(ip)) {
-		ASSERT(ip->i_d.di_forkoff != 0);
-
 		error = xfs_attr_inactive(ip);
 		if (error)
 			return;
 	}
 
-	if (ip->i_afp)
+	ASSERT(!ip->i_afp);
-		xfs_idestroy_fork(ip, XFS_ATTR_FORK);
-
 	ASSERT(ip->i_d.di_anextents == 0);
+	ASSERT(ip->i_d.di_forkoff == 0);
 
 	/*
 	 * Free the inode.
@@ -2883,7 +2879,13 @@ xfs_rename_alloc_whiteout(
 	if (error)
 		return error;
 
-	/* Satisfy xfs_bumplink that this is a real tmpfile */
+	/*
+	 * Prepare the tmpfile inode as if it were created through the VFS.
+	 * Otherwise, the link increment paths will complain about nlink 0->1.
+	 * Drop the link count as done by d_tmpfile(), complete the inode setup
+	 * and flag it as linkable.
+	 */
+	drop_nlink(VFS_I(tmpfile));
 	xfs_finish_inode_setup(tmpfile);
 	VFS_I(tmpfile)->i_state |= I_LINKABLE;
 
@@ -3151,7 +3153,7 @@ xfs_rename(
 	 * intermediate state on disk.
 	 */
 	if (wip) {
-		ASSERT(wip->i_d.di_nlink == 0);
+		ASSERT(VFS_I(wip)->i_nlink == 0 && wip->i_d.di_nlink == 0);
 		error = xfs_bumplink(tp, wip);
 		if (error)
 			goto out_trans_abort;

fs/xfs/xfs_mount.c

@@ -1084,14 +1084,18 @@ xfs_log_sbcount(xfs_mount_t *mp)
 	return xfs_sync_sb(mp, true);
 }
 
+/*
+ * Deltas for the inode count are +/-64, hence we use a large batch size
+ * of 128 so we don't need to take the counter lock on every update.
+ */
+#define XFS_ICOUNT_BATCH	128
 int
 xfs_mod_icount(
 	struct xfs_mount	*mp,
 	int64_t			delta)
 {
-	/* deltas are +/-64, hence the large batch size of 128. */
+	__percpu_counter_add(&mp->m_icount, delta, XFS_ICOUNT_BATCH);
-	__percpu_counter_add(&mp->m_icount, delta, 128);
+	if (__percpu_counter_compare(&mp->m_icount, 0, XFS_ICOUNT_BATCH) < 0) {
-	if (percpu_counter_compare(&mp->m_icount, 0) < 0) {
 		ASSERT(0);
 		percpu_counter_add(&mp->m_icount, -delta);
 		return -EINVAL;
@@ -1113,6 +1117,14 @@ xfs_mod_ifree(
 	return 0;
 }
 
+/*
+ * Deltas for the block count can vary from 1 to very large, but lock contention
+ * only occurs on frequent small block count updates such as in the delayed
+ * allocation path for buffered writes (page a time updates). Hence we set
+ * a large batch count (1024) to minimise global counter updates except when
+ * we get near to ENOSPC and we have to be very accurate with our updates.
+ */
+#define XFS_FDBLOCKS_BATCH	1024
 int
 xfs_mod_fdblocks(
 	struct xfs_mount	*mp,
@@ -1151,25 +1163,19 @@ xfs_mod_fdblocks(
 	 * Taking blocks away, need to be more accurate the closer we
 	 * are to zero.
 	 *
-	 * batch size is set to a maximum of 1024 blocks - if we are
-	 * allocating of freeing extents larger than this then we aren't
-	 * going to be hammering the counter lock so a lock per update
-	 * is not a problem.
-	 *
 	 * If the counter has a value of less than 2 * max batch size,
 	 * then make everything serialise as we are real close to
 	 * ENOSPC.
 	 */
-#define __BATCH	1024
+	if (__percpu_counter_compare(&mp->m_fdblocks, 2 * XFS_FDBLOCKS_BATCH,
-	if (percpu_counter_compare(&mp->m_fdblocks, 2 * __BATCH) < 0)
+				     XFS_FDBLOCKS_BATCH) < 0)
 		batch = 1;
 	else
-		batch = __BATCH;
+		batch = XFS_FDBLOCKS_BATCH;
-#undef __BATCH
 
 	__percpu_counter_add(&mp->m_fdblocks, delta, batch);
-	if (percpu_counter_compare(&mp->m_fdblocks,
+	if (__percpu_counter_compare(&mp->m_fdblocks, XFS_ALLOC_SET_ASIDE(mp),
-				   XFS_ALLOC_SET_ASIDE(mp)) >= 0) {
+				     XFS_FDBLOCKS_BATCH) >= 0) {
 		/* we had space! */
 		return 0;
 	}

include/linux/percpu_counter.h

@@ -41,7 +41,12 @@ void percpu_counter_destroy(struct percpu_counter *fbc);
 void percpu_counter_set(struct percpu_counter *fbc, s64 amount);
 void __percpu_counter_add(struct percpu_counter *fbc, s64 amount, s32 batch);
 s64 __percpu_counter_sum(struct percpu_counter *fbc);
-int percpu_counter_compare(struct percpu_counter *fbc, s64 rhs);
+int __percpu_counter_compare(struct percpu_counter *fbc, s64 rhs, s32 batch);
+
+static inline int percpu_counter_compare(struct percpu_counter *fbc, s64 rhs)
+{
+	return __percpu_counter_compare(fbc, rhs, percpu_counter_batch);
+}
 
 static inline void percpu_counter_add(struct percpu_counter *fbc, s64 amount)
 {
@@ -116,6 +121,12 @@ static inline int percpu_counter_compare(struct percpu_counter *fbc, s64 rhs)
 		return 0;
 }
 
+static inline int
+__percpu_counter_compare(struct percpu_counter *fbc, s64 rhs, s32 batch)
+{
+	return percpu_counter_compare(fbc, rhs);
+}
+
 static inline void
 percpu_counter_add(struct percpu_counter *fbc, s64 amount)
 {

lib/percpu_counter.c

@@ -197,13 +197,13 @@ static int percpu_counter_hotcpu_callback(struct notifier_block *nb,
  * Compare counter against given value.
  * Return 1 if greater, 0 if equal and -1 if less
  */
-int percpu_counter_compare(struct percpu_counter *fbc, s64 rhs)
+int __percpu_counter_compare(struct percpu_counter *fbc, s64 rhs, s32 batch)
 {
 	s64	count;
 
 	count = percpu_counter_read(fbc);
 	/* Check to see if rough count will be sufficient for comparison */
-	if (abs(count - rhs) > (percpu_counter_batch*num_online_cpus())) {
+	if (abs(count - rhs) > (batch * num_online_cpus())) {
 		if (count > rhs)
 			return 1;
 		else
@@ -218,7 +218,7 @@ int percpu_counter_compare(struct percpu_counter *fbc, s64 rhs)
 	else
 		return 0;
 }
-EXPORT_SYMBOL(percpu_counter_compare);
+EXPORT_SYMBOL(__percpu_counter_compare);
 
 static int __init percpu_counter_startup(void)
 {