[PATCH v2 03/18] include/ceph/ceph_fs.h: convert `pool_id` to u32

[Max Kellermann <max.kellermann@ionos.com>]

While the Ceph OSD protocol transmits OSD pool ids as 64 bit integers,
the MDS protocol is limited to 32 bits.  This is a protocol limitation
we cannot fix, but it gives us the chance to reduce the struct sizes
by only using the integer size we really need.

There is one caveat: previously, -1 was used to indicate "invalid pool
id".  This patch changes this magic value to 0 (i.e. removes the
special-case code from ceph_file_layout_{from,to}_legacy()).  This is
fine because on the wire, this magic value is 0, too.

This reduces the size of `struct ceph_inode_info` by 16 bytes (because
it contains `struct ceph_file_layout` twice, and that struct shrinks
by 8 bytes; the small pool_id now fits in the existing padding hole).

Signed-off-by: Max Kellermann <max.kellermann@ionos.com>
---
 fs/ceph/addr.c               | 16 ++++++++--------
 fs/ceph/caps.c               |  2 +-
 fs/ceph/inode.c              |  2 +-
 fs/ceph/mds_client.h         |  2 +-
 fs/ceph/util.c               |  8 +-------
 fs/ceph/xattr.c              | 10 +++++-----
 include/linux/ceph/ceph_fs.h |  2 +-
 7 files changed, 18 insertions(+), 24 deletions(-)

diff --git a/fs/ceph/addr.c b/fs/ceph/addr.c
index 61bd6d92ff25..481654872e9f 100644
--- a/fs/ceph/addr.c
+++ b/fs/ceph/addr.c
@@ -2381,7 +2381,7 @@ enum {
 };
 
 static int __ceph_pool_perm_get(struct ceph_inode_info *ci,
-				s64 pool, struct ceph_string *pool_ns)
+				u32 pool, struct ceph_string *pool_ns)
 {
 	struct ceph_fs_client *fsc = ceph_inode_to_fs_client(&ci->netfs.inode);
 	struct ceph_mds_client *mdsc = fsc->mdsc;
@@ -2420,10 +2420,10 @@ static int __ceph_pool_perm_get(struct ceph_inode_info *ci,
 		goto out;
 
 	if (pool_ns)
-		doutc(cl, "pool %lld ns %.*s no perm cached\n", pool,
+		doutc(cl, "pool %u ns %.*s no perm cached\n", pool,
 		      (int)pool_ns->len, pool_ns->str);
 	else
-		doutc(cl, "pool %lld no perm cached\n", pool);
+		doutc(cl, "pool %u no perm cached\n", pool);
 
 	down_write(&mdsc->pool_perm_rwsem);
 	p = &mdsc->pool_perm_tree.rb_node;
@@ -2548,10 +2548,10 @@ static int __ceph_pool_perm_get(struct ceph_inode_info *ci,
 	if (!err)
 		err = have;
 	if (pool_ns)
-		doutc(cl, "pool %lld ns %.*s result = %d\n", pool,
+		doutc(cl, "pool %u ns %.*s result = %d\n", pool,
 		      (int)pool_ns->len, pool_ns->str, err);
 	else
-		doutc(cl, "pool %lld result = %d\n", pool, err);
+		doutc(cl, "pool %u result = %d\n", pool, err);
 	return err;
 }
 
@@ -2560,7 +2560,7 @@ int ceph_pool_perm_check(struct inode *inode, int need)
 	struct ceph_client *cl = ceph_inode_to_client(inode);
 	struct ceph_inode_info *ci = ceph_inode(inode);
 	struct ceph_string *pool_ns;
-	s64 pool;
+	u32 pool;
 	int ret;
 	unsigned long flags;
 
@@ -2588,11 +2588,11 @@ int ceph_pool_perm_check(struct inode *inode, int need)
 check:
 	if (flags & CEPH_I_POOL_PERM) {
 		if ((need & CEPH_CAP_FILE_RD) && !(flags & CEPH_I_POOL_RD)) {
-			doutc(cl, "pool %lld no read perm\n", pool);
+			doutc(cl, "pool %u no read perm\n", pool);
 			return -EPERM;
 		}
 		if ((need & CEPH_CAP_FILE_WR) && !(flags & CEPH_I_POOL_WR)) {
-			doutc(cl, "pool %lld no write perm\n", pool);
+			doutc(cl, "pool %u no write perm\n", pool);
 			return -EPERM;
 		}
 		return 0;
diff --git a/fs/ceph/caps.c b/fs/ceph/caps.c
index 4b37d9ffdf7f..39dad1a528b5 100644
--- a/fs/ceph/caps.c
+++ b/fs/ceph/caps.c
@@ -3641,7 +3641,7 @@ static void handle_cap_grant(struct inode *inode,
 
 	if (newcaps & (CEPH_CAP_ANY_FILE_RD | CEPH_CAP_ANY_FILE_WR)) {
 		/* file layout may have changed */
-		s64 old_pool = ci->i_layout.pool_id;
+		u32 old_pool = ci->i_layout.pool_id;
 		struct ceph_string *old_ns;
 
 		ceph_file_layout_from_legacy(&ci->i_layout, &grant->layout);
diff --git a/fs/ceph/inode.c b/fs/ceph/inode.c
index bdb82f123033..cd1e09c32eba 100644
--- a/fs/ceph/inode.c
+++ b/fs/ceph/inode.c
@@ -1176,7 +1176,7 @@ int ceph_fill_inode(struct inode *inode, struct page *locked_page,
 	if (new_version ||
 	    (new_issued & (CEPH_CAP_ANY_FILE_RD | CEPH_CAP_ANY_FILE_WR))) {
 		u64 size = le64_to_cpu(info->size);
-		s64 old_pool = ci->i_layout.pool_id;
+		u32 old_pool = ci->i_layout.pool_id;
 		struct ceph_string *old_ns;
 
 		ceph_file_layout_from_legacy(&ci->i_layout, &info->layout);
diff --git a/fs/ceph/mds_client.h b/fs/ceph/mds_client.h
index 731d6ad04956..d59bc904f0ce 100644
--- a/fs/ceph/mds_client.h
+++ b/fs/ceph/mds_client.h
@@ -440,7 +440,7 @@ struct ceph_mds_request {
 struct ceph_pool_perm {
 	struct rb_node node;
 	int perm;
-	s64 pool;
+	u32 pool;
 	size_t pool_ns_len;
 	char pool_ns[];
 };
diff --git a/fs/ceph/util.c b/fs/ceph/util.c
index 2c34875675bf..5bb40af08b1c 100644
--- a/fs/ceph/util.c
+++ b/fs/ceph/util.c
@@ -35,9 +35,6 @@ void ceph_file_layout_from_legacy(struct ceph_file_layout *fl,
 	fl->stripe_count = le32_to_cpu(legacy->fl_stripe_count);
 	fl->object_size = le32_to_cpu(legacy->fl_object_size);
 	fl->pool_id = le32_to_cpu(legacy->fl_pg_pool);
-	if (fl->pool_id == 0 && fl->stripe_unit == 0 &&
-	    fl->stripe_count == 0 && fl->object_size == 0)
-		fl->pool_id = -1;
 }
 
 void ceph_file_layout_to_legacy(struct ceph_file_layout *fl,
@@ -46,10 +43,7 @@ void ceph_file_layout_to_legacy(struct ceph_file_layout *fl,
 	legacy->fl_stripe_unit = cpu_to_le32(fl->stripe_unit);
 	legacy->fl_stripe_count = cpu_to_le32(fl->stripe_count);
 	legacy->fl_object_size = cpu_to_le32(fl->object_size);
-	if (fl->pool_id >= 0)
-		legacy->fl_pg_pool = cpu_to_le32(fl->pool_id);
-	else
-		legacy->fl_pg_pool = 0;
+	legacy->fl_pg_pool = cpu_to_le32(fl->pool_id);
 }
 
 int ceph_flags_to_mode(int flags)
diff --git a/fs/ceph/xattr.c b/fs/ceph/xattr.c
index 860fc8e1867d..124dde705e79 100644
--- a/fs/ceph/xattr.c
+++ b/fs/ceph/xattr.c
@@ -50,7 +50,7 @@ static bool ceph_vxattrcb_layout_exists(struct ceph_inode_info *ci)
 {
 	struct ceph_file_layout *fl = &ci->i_layout;
 	return (fl->stripe_unit > 0 || fl->stripe_count > 0 ||
-		fl->object_size > 0 || fl->pool_id >= 0 ||
+		fl->object_size > 0 || fl->pool_id > 0 ||
 		rcu_dereference_raw(fl->pool_ns) != NULL);
 }
 
@@ -61,7 +61,7 @@ static ssize_t ceph_vxattrcb_layout(struct ceph_inode_info *ci, char *val,
 	struct ceph_client *cl = fsc->client;
 	struct ceph_osd_client *osdc = &fsc->client->osdc;
 	struct ceph_string *pool_ns;
-	s64 pool = ci->i_layout.pool_id;
+	u32 pool = ci->i_layout.pool_id;
 	const char *pool_name;
 	const char *ns_field = " pool_namespace=";
 	char buf[128];
@@ -81,7 +81,7 @@ static ssize_t ceph_vxattrcb_layout(struct ceph_inode_info *ci, char *val,
 		total_len = len + strlen(pool_name);
 	} else {
 		len = snprintf(buf, sizeof(buf),
-		"stripe_unit=%u stripe_count=%u object_size=%u pool=%lld",
+		"stripe_unit=%u stripe_count=%u object_size=%u pool=%u",
 		ci->i_layout.stripe_unit, ci->i_layout.stripe_count,
 		ci->i_layout.object_size, pool);
 		total_len = len;
@@ -164,7 +164,7 @@ static ssize_t ceph_vxattrcb_layout_pool(struct ceph_inode_info *ci,
 	ssize_t ret;
 	struct ceph_fs_client *fsc = ceph_sb_to_fs_client(ci->netfs.inode.i_sb);
 	struct ceph_osd_client *osdc = &fsc->client->osdc;
-	s64 pool = ci->i_layout.pool_id;
+	u32 pool = ci->i_layout.pool_id;
 	const char *pool_name;
 
 	down_read(&osdc->lock);
@@ -174,7 +174,7 @@ static ssize_t ceph_vxattrcb_layout_pool(struct ceph_inode_info *ci,
 		if (ret <= size)
 			memcpy(val, pool_name, ret);
 	} else {
-		ret = ceph_fmt_xattr(val, size, "%lld", pool);
+		ret = ceph_fmt_xattr(val, size, "%u", pool);
 	}
 	up_read(&osdc->lock);
 	return ret;
diff --git a/include/linux/ceph/ceph_fs.h b/include/linux/ceph/ceph_fs.h
index 69ac3e55a3fe..7faa18493a07 100644
--- a/include/linux/ceph/ceph_fs.h
+++ b/include/linux/ceph/ceph_fs.h
@@ -69,7 +69,7 @@ struct ceph_file_layout {
 	u32 stripe_unit;   /* stripe unit, in bytes */
 	u32 stripe_count;  /* over this many objects */
 	u32 object_size;   /* until objects are this big */
-	s64 pool_id;        /* rados pool id */
+	u32 pool_id;        /* rados pool id */
 	struct ceph_string __rcu *pool_ns; /* rados pool namespace */
 };
 
-- 
2.47.3