From 48ff40458f871fb19e7b1b40e0e5084b8751d9cb Mon Sep 17 00:00:00 2001
From: "Darrick J. Wong" <djwong@kernel.org>
Date: Sun, 6 Nov 2022 17:03:15 -0800
Subject: [PATCH 1/3] xfs: standardize GFP flags usage in online scrub

Memory allocation usage is the same throughout online fsck -- we want
kernel memory, we have to be able to back out if we can't allocate
memory, and we don't want to spray dmesg with memory allocation failure
reports.  Standardize the GFP flag usage and document these requirements.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
---
 fs/xfs/scrub/agheader.c | 2 +-
 fs/xfs/scrub/attr.c     | 9 ++++-----
 fs/xfs/scrub/scrub.h    | 9 +++++++++
 fs/xfs/scrub/symlink.c  | 2 +-
 4 files changed, 15 insertions(+), 7 deletions(-)

diff --git a/fs/xfs/scrub/agheader.c b/fs/xfs/scrub/agheader.c
index af284baa6f4c..4dd52b15f09c 100644
--- a/fs/xfs/scrub/agheader.c
+++ b/fs/xfs/scrub/agheader.c
@@ -737,7 +737,7 @@ xchk_agfl(
 		goto out;
 	}
 	sai.entries = kvcalloc(sai.agflcount, sizeof(xfs_agblock_t),
-			GFP_KERNEL | __GFP_RETRY_MAYFAIL);
+			       XCHK_GFP_FLAGS);
 	if (!sai.entries) {
 		error = -ENOMEM;
 		goto out;
diff --git a/fs/xfs/scrub/attr.c b/fs/xfs/scrub/attr.c
index b6f0c9f3f124..11b2593a2be7 100644
--- a/fs/xfs/scrub/attr.c
+++ b/fs/xfs/scrub/attr.c
@@ -79,7 +79,8 @@ xchk_setup_xattr(
 	 * without the inode lock held, which means we can sleep.
 	 */
 	if (sc->flags & XCHK_TRY_HARDER) {
-		error = xchk_setup_xattr_buf(sc, XATTR_SIZE_MAX, GFP_KERNEL);
+		error = xchk_setup_xattr_buf(sc, XATTR_SIZE_MAX,
+				XCHK_GFP_FLAGS);
 		if (error)
 			return error;
 	}
@@ -138,8 +139,7 @@ xchk_xattr_listent(
 	 * doesn't work, we overload the seen_enough variable to convey
 	 * the error message back to the main scrub function.
 	 */
-	error = xchk_setup_xattr_buf(sx->sc, valuelen,
-			GFP_KERNEL | __GFP_RETRY_MAYFAIL);
+	error = xchk_setup_xattr_buf(sx->sc, valuelen, XCHK_GFP_FLAGS);
 	if (error == -ENOMEM)
 		error = -EDEADLOCK;
 	if (error) {
@@ -324,8 +324,7 @@ xchk_xattr_block(
 		return 0;
 
 	/* Allocate memory for block usage checking. */
-	error = xchk_setup_xattr_buf(ds->sc, 0,
-			GFP_KERNEL | __GFP_RETRY_MAYFAIL);
+	error = xchk_setup_xattr_buf(ds->sc, 0, XCHK_GFP_FLAGS);
 	if (error == -ENOMEM)
 		return -EDEADLOCK;
 	if (error)
diff --git a/fs/xfs/scrub/scrub.h b/fs/xfs/scrub/scrub.h
index 151567f88366..a0f097b8acb0 100644
--- a/fs/xfs/scrub/scrub.h
+++ b/fs/xfs/scrub/scrub.h
@@ -8,6 +8,15 @@
 
 struct xfs_scrub;
 
+/*
+ * Standard flags for allocating memory within scrub.  NOFS context is
+ * configured by the process allocation scope.  Scrub and repair must be able
+ * to back out gracefully if there isn't enough memory.  Force-cast to avoid
+ * complaints from static checkers.
+ */
+#define XCHK_GFP_FLAGS	((__force gfp_t)(GFP_KERNEL | __GFP_NOWARN | \
+					 __GFP_RETRY_MAYFAIL))
+
 /* Type info and names for the scrub types. */
 enum xchk_type {
 	ST_NONE = 1,	/* disabled */
diff --git a/fs/xfs/scrub/symlink.c b/fs/xfs/scrub/symlink.c
index 75311f8daeeb..c1c99ffe7408 100644
--- a/fs/xfs/scrub/symlink.c
+++ b/fs/xfs/scrub/symlink.c
@@ -21,7 +21,7 @@ xchk_setup_symlink(
 	struct xfs_scrub	*sc)
 {
 	/* Allocate the buffer without the inode lock held. */
-	sc->buf = kvzalloc(XFS_SYMLINK_MAXLEN + 1, GFP_KERNEL);
+	sc->buf = kvzalloc(XFS_SYMLINK_MAXLEN + 1, XCHK_GFP_FLAGS);
 	if (!sc->buf)
 		return -ENOMEM;
 

From fcd2a43488d5a211aec94e28369b2a72c28258a2 Mon Sep 17 00:00:00 2001
From: "Darrick J. Wong" <djwong@kernel.org>
Date: Sun, 6 Nov 2022 17:03:15 -0800
Subject: [PATCH 2/3] xfs: initialize the check_owner object fully

Initialize the check_owner list head so that we don't corrupt the list.
Reduce the scope of the object pointer.

Fixes: 858333dcf021 ("xfs: check btree block ownership with bnobt/rmapbt when scrubbing btree")
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
---
 fs/xfs/scrub/btree.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/fs/xfs/scrub/btree.c b/fs/xfs/scrub/btree.c
index 2f4519590dc1..075ff3071122 100644
--- a/fs/xfs/scrub/btree.c
+++ b/fs/xfs/scrub/btree.c
@@ -408,7 +408,6 @@ xchk_btree_check_owner(
 	struct xfs_buf		*bp)
 {
 	struct xfs_btree_cur	*cur = bs->cur;
-	struct check_owner	*co;
 
 	/*
 	 * In theory, xfs_btree_get_block should only give us a null buffer
@@ -431,10 +430,14 @@ xchk_btree_check_owner(
 	 * later scanning.
 	 */
 	if (cur->bc_btnum == XFS_BTNUM_BNO || cur->bc_btnum == XFS_BTNUM_RMAP) {
+		struct check_owner	*co;
+
 		co = kmem_alloc(sizeof(struct check_owner),
 				KM_MAYFAIL);
 		if (!co)
 			return -ENOMEM;
+
+		INIT_LIST_HEAD(&co->list);
 		co->level = level;
 		co->daddr = xfs_buf_daddr(bp);
 		list_add_tail(&co->list, &bs->to_check);

From 306195f355bbdcc3eff6cffac05bcd93a5e419ed Mon Sep 17 00:00:00 2001
From: "Darrick J. Wong" <djwong@kernel.org>
Date: Sun, 6 Nov 2022 17:03:16 -0800
Subject: [PATCH 3/3] xfs: pivot online scrub away from kmem.[ch]

Convert all the online scrub code to use the Linux slab allocator
functions directly instead of going through the kmem wrappers.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
---
 fs/xfs/scrub/agheader_repair.c |  2 +-
 fs/xfs/scrub/attr.c            |  2 +-
 fs/xfs/scrub/bitmap.c          | 11 ++++++-----
 fs/xfs/scrub/btree.c           |  9 ++++-----
 fs/xfs/scrub/dabtree.c         |  4 ++--
 fs/xfs/scrub/fscounters.c      |  2 +-
 fs/xfs/scrub/refcount.c        | 12 ++++++------
 fs/xfs/scrub/scrub.c           |  6 +++---
 8 files changed, 24 insertions(+), 24 deletions(-)

diff --git a/fs/xfs/scrub/agheader_repair.c b/fs/xfs/scrub/agheader_repair.c
index 82ceb60ea5fc..d75d82151eeb 100644
--- a/fs/xfs/scrub/agheader_repair.c
+++ b/fs/xfs/scrub/agheader_repair.c
@@ -685,7 +685,7 @@ xrep_agfl_init_header(
 		if (br->len)
 			break;
 		list_del(&br->list);
-		kmem_free(br);
+		kfree(br);
 	}
 
 	/* Write new AGFL to disk. */
diff --git a/fs/xfs/scrub/attr.c b/fs/xfs/scrub/attr.c
index 11b2593a2be7..31529b9bf389 100644
--- a/fs/xfs/scrub/attr.c
+++ b/fs/xfs/scrub/attr.c
@@ -49,7 +49,7 @@ xchk_setup_xattr_buf(
 	if (ab) {
 		if (sz <= ab->sz)
 			return 0;
-		kmem_free(ab);
+		kvfree(ab);
 		sc->buf = NULL;
 	}
 
diff --git a/fs/xfs/scrub/bitmap.c b/fs/xfs/scrub/bitmap.c
index b89bf9de9b1c..a255f09e9f0a 100644
--- a/fs/xfs/scrub/bitmap.c
+++ b/fs/xfs/scrub/bitmap.c
@@ -10,6 +10,7 @@
 #include "xfs_trans_resv.h"
 #include "xfs_mount.h"
 #include "xfs_btree.h"
+#include "scrub/scrub.h"
 #include "scrub/bitmap.h"
 
 /*
@@ -25,7 +26,7 @@ xbitmap_set(
 {
 	struct xbitmap_range	*bmr;
 
-	bmr = kmem_alloc(sizeof(struct xbitmap_range), KM_MAYFAIL);
+	bmr = kmalloc(sizeof(struct xbitmap_range), XCHK_GFP_FLAGS);
 	if (!bmr)
 		return -ENOMEM;
 
@@ -47,7 +48,7 @@ xbitmap_destroy(
 
 	for_each_xbitmap_extent(bmr, n, bitmap) {
 		list_del(&bmr->list);
-		kmem_free(bmr);
+		kfree(bmr);
 	}
 }
 
@@ -174,15 +175,15 @@ xbitmap_disunion(
 			/* Total overlap, just delete ex. */
 			lp = lp->next;
 			list_del(&br->list);
-			kmem_free(br);
+			kfree(br);
 			break;
 		case 0:
 			/*
 			 * Deleting from the middle: add the new right extent
 			 * and then shrink the left extent.
 			 */
-			new_br = kmem_alloc(sizeof(struct xbitmap_range),
-					KM_MAYFAIL);
+			new_br = kmalloc(sizeof(struct xbitmap_range),
+					XCHK_GFP_FLAGS);
 			if (!new_br) {
 				error = -ENOMEM;
 				goto out;
diff --git a/fs/xfs/scrub/btree.c b/fs/xfs/scrub/btree.c
index 075ff3071122..0fd36d5b4646 100644
--- a/fs/xfs/scrub/btree.c
+++ b/fs/xfs/scrub/btree.c
@@ -432,8 +432,7 @@ xchk_btree_check_owner(
 	if (cur->bc_btnum == XFS_BTNUM_BNO || cur->bc_btnum == XFS_BTNUM_RMAP) {
 		struct check_owner	*co;
 
-		co = kmem_alloc(sizeof(struct check_owner),
-				KM_MAYFAIL);
+		co = kmalloc(sizeof(struct check_owner), XCHK_GFP_FLAGS);
 		if (!co)
 			return -ENOMEM;
 
@@ -652,7 +651,7 @@ xchk_btree(
 		xchk_btree_set_corrupt(sc, cur, 0);
 		return 0;
 	}
-	bs = kmem_zalloc(cur_sz, KM_NOFS | KM_MAYFAIL);
+	bs = kzalloc(cur_sz, XCHK_GFP_FLAGS);
 	if (!bs)
 		return -ENOMEM;
 	bs->cur = cur;
@@ -743,9 +742,9 @@ xchk_btree(
 			error = xchk_btree_check_block_owner(bs, co->level,
 					co->daddr);
 		list_del(&co->list);
-		kmem_free(co);
+		kfree(co);
 	}
-	kmem_free(bs);
+	kfree(bs);
 
 	return error;
 }
diff --git a/fs/xfs/scrub/dabtree.c b/fs/xfs/scrub/dabtree.c
index 84fe3d33d699..d17cee177085 100644
--- a/fs/xfs/scrub/dabtree.c
+++ b/fs/xfs/scrub/dabtree.c
@@ -486,7 +486,7 @@ xchk_da_btree(
 		return 0;
 
 	/* Set up initial da state. */
-	ds = kmem_zalloc(sizeof(struct xchk_da_btree), KM_NOFS | KM_MAYFAIL);
+	ds = kzalloc(sizeof(struct xchk_da_btree), XCHK_GFP_FLAGS);
 	if (!ds)
 		return -ENOMEM;
 	ds->dargs.dp = sc->ip;
@@ -591,6 +591,6 @@ xchk_da_btree(
 
 out_state:
 	xfs_da_state_free(ds->state);
-	kmem_free(ds);
+	kfree(ds);
 	return error;
 }
diff --git a/fs/xfs/scrub/fscounters.c b/fs/xfs/scrub/fscounters.c
index 6a6f8fe7f87c..3c56f5890da4 100644
--- a/fs/xfs/scrub/fscounters.c
+++ b/fs/xfs/scrub/fscounters.c
@@ -116,7 +116,7 @@ xchk_setup_fscounters(
 	struct xchk_fscounters	*fsc;
 	int			error;
 
-	sc->buf = kmem_zalloc(sizeof(struct xchk_fscounters), 0);
+	sc->buf = kzalloc(sizeof(struct xchk_fscounters), XCHK_GFP_FLAGS);
 	if (!sc->buf)
 		return -ENOMEM;
 	fsc = sc->buf;
diff --git a/fs/xfs/scrub/refcount.c b/fs/xfs/scrub/refcount.c
index a26ee0f24ef2..d9c1b3cea4a5 100644
--- a/fs/xfs/scrub/refcount.c
+++ b/fs/xfs/scrub/refcount.c
@@ -127,8 +127,8 @@ xchk_refcountbt_rmap_check(
 		 * is healthy each rmap_irec we see will be in agbno order
 		 * so we don't need insertion sort here.
 		 */
-		frag = kmem_alloc(sizeof(struct xchk_refcnt_frag),
-				KM_MAYFAIL);
+		frag = kmalloc(sizeof(struct xchk_refcnt_frag),
+				XCHK_GFP_FLAGS);
 		if (!frag)
 			return -ENOMEM;
 		memcpy(&frag->rm, rec, sizeof(frag->rm));
@@ -215,7 +215,7 @@ xchk_refcountbt_process_rmap_fragments(
 				continue;
 			}
 			list_del(&frag->list);
-			kmem_free(frag);
+			kfree(frag);
 			nr++;
 		}
 
@@ -257,11 +257,11 @@ xchk_refcountbt_process_rmap_fragments(
 	/* Delete fragments and work list. */
 	list_for_each_entry_safe(frag, n, &worklist, list) {
 		list_del(&frag->list);
-		kmem_free(frag);
+		kfree(frag);
 	}
 	list_for_each_entry_safe(frag, n, &refchk->fragments, list) {
 		list_del(&frag->list);
-		kmem_free(frag);
+		kfree(frag);
 	}
 }
 
@@ -306,7 +306,7 @@ xchk_refcountbt_xref_rmap(
 out_free:
 	list_for_each_entry_safe(frag, n, &refchk.fragments, list) {
 		list_del(&frag->list);
-		kmem_free(frag);
+		kfree(frag);
 	}
 }
 
diff --git a/fs/xfs/scrub/scrub.c b/fs/xfs/scrub/scrub.c
index 2e8e400f10a9..07a7a75f987f 100644
--- a/fs/xfs/scrub/scrub.c
+++ b/fs/xfs/scrub/scrub.c
@@ -174,7 +174,7 @@ xchk_teardown(
 	if (sc->flags & XCHK_REAPING_DISABLED)
 		xchk_start_reaping(sc);
 	if (sc->buf) {
-		kmem_free(sc->buf);
+		kvfree(sc->buf);
 		sc->buf = NULL;
 	}
 	return error;
@@ -467,7 +467,7 @@ xfs_scrub_metadata(
 	xfs_warn_mount(mp, XFS_OPSTATE_WARNED_SCRUB,
  "EXPERIMENTAL online scrub feature in use. Use at your own risk!");
 
-	sc = kmem_zalloc(sizeof(struct xfs_scrub), KM_NOFS | KM_MAYFAIL);
+	sc = kzalloc(sizeof(struct xfs_scrub), XCHK_GFP_FLAGS);
 	if (!sc) {
 		error = -ENOMEM;
 		goto out;
@@ -557,7 +557,7 @@ xfs_scrub_metadata(
 out_teardown:
 	error = xchk_teardown(sc, error);
 out_sc:
-	kmem_free(sc);
+	kfree(sc);
 out:
 	trace_xchk_done(XFS_I(file_inode(file)), sm, error);
 	if (error == -EFSCORRUPTED || error == -EFSBADCRC) {