[patch 4/4] reiser4: reduce frame size of reiser4_init_super_data

[patch 4/4] reiser4: reduce frame size of reiser4_init_super_data

[Edward Shishkin]

[-- Attachment #1: Type: text/plain, Size: 1 bytes --]



[-- Attachment #2: reiser4-reduce-frame-size.patch --]
[-- Type: text/plain, Size: 5784 bytes --]

Address a gcc warning for x86_64 about large frame size.
Add a new function push_sb_field_opts(). 

Signed-off-by Edward Shsihkin <edward.shishkin@gmail.com>
---
 fs/reiser4/init_super.c |  126 +++++++++++++++++++++++++-----------------------
 1 file changed, 66 insertions(+), 60 deletions(-)

--- mmotm.orig/fs/reiser4/init_super.c
+++ mmotm/fs/reiser4/init_super.c
@@ -292,66 +292,6 @@ static int parse_options(char *opt_strin
 
 #define MAX_NR_OPTIONS (30)
 
-/**
- * reiser4_init_super_data - initialize reiser4 private super block
- * @super: super block to initialize
- * @opt_string: list of reiser4 mount options
- *
- * Sets various reiser4 parameters to default values. Parses mount options and
- * overwrites default settings.
- */
-int reiser4_init_super_data(struct super_block *super, char *opt_string)
-{
-	int result;
-	struct opt_desc *opts, *p;
-	reiser4_super_info_data *sbinfo = get_super_private(super);
-
-	/* initialize super, export, dentry operations */
-	sbinfo->ops.super = reiser4_super_operations;
-	sbinfo->ops.export = reiser4_export_operations;
-	sbinfo->ops.dentry = reiser4_dentry_operations;
-	super->s_op = &sbinfo->ops.super;
-	super->s_export_op = &sbinfo->ops.export;
-
-	/* initialize transaction manager parameters to default values */
-	sbinfo->tmgr.atom_max_size = totalram_pages / 4;
-	sbinfo->tmgr.atom_max_age = REISER4_ATOM_MAX_AGE / HZ;
-	sbinfo->tmgr.atom_min_size = 256;
-	sbinfo->tmgr.atom_max_flushers = ATOM_MAX_FLUSHERS;
-
-	/* initialize cbk cache parameter */
-	sbinfo->tree.cbk_cache.nr_slots = CBK_CACHE_SLOTS;
-
-	/* initialize flush parameters */
-	sbinfo->flush.relocate_threshold = FLUSH_RELOCATE_THRESHOLD;
-	sbinfo->flush.relocate_distance = FLUSH_RELOCATE_DISTANCE;
-	sbinfo->flush.written_threshold = FLUSH_WRITTEN_THRESHOLD;
-	sbinfo->flush.scan_maxnodes = FLUSH_SCAN_MAXNODES;
-
-	sbinfo->optimal_io_size = REISER4_OPTIMAL_IO_SIZE;
-
-	/* preliminary tree initializations */
-	sbinfo->tree.super = super;
-	sbinfo->tree.carry.new_node_flags = REISER4_NEW_NODE_FLAGS;
-	sbinfo->tree.carry.new_extent_flags = REISER4_NEW_EXTENT_FLAGS;
-	sbinfo->tree.carry.paste_flags = REISER4_PASTE_FLAGS;
-	sbinfo->tree.carry.insert_flags = REISER4_INSERT_FLAGS;
-	rwlock_init(&(sbinfo->tree.tree_lock));
-	spin_lock_init(&(sbinfo->tree.epoch_lock));
-
-	/* initialize default readahead params */
-	sbinfo->ra_params.max = num_physpages / 4;
-	sbinfo->ra_params.flags = 0;
-
-	/* allocate memory for structure describing reiser4 mount options */
-	opts = kmalloc(sizeof(struct opt_desc) * MAX_NR_OPTIONS,
-		       reiser4_ctx_gfp_mask_get());
-	if (opts == NULL)
-		return RETERR(-ENOMEM);
-
-	/* initialize structure describing reiser4 mount options */
-	p = opts;
-
 #if REISER4_DEBUG
 #  define OPT_ARRAY_CHECK if ((p) > (opts) + MAX_NR_OPTIONS) {		\
 		warning("zam-1046", "opt array is overloaded"); break;	\
@@ -370,6 +310,10 @@ do {						\
 #define PUSH_SB_FIELD_OPT(field, format) PUSH_OPT(SB_FIELD_OPT(field, format))
 #define PUSH_BIT_OPT(name, bit) PUSH_OPT(BIT_OPT(name, bit))
 
+static noinline void push_sb_field_opts(struct opt_desc *p,
+					struct opt_desc *opts,
+					reiser4_super_info_data *sbinfo)
+{
 	/*
 	 * tmgr.atom_max_size=N
 	 * Atoms containing more than N blocks will be forced to commit. N is
@@ -435,7 +379,69 @@ do {						\
 	 */
 	PUSH_SB_FIELD_OPT(altsuper, "%lu");
 #endif
+}
+
+/**
+ * reiser4_init_super_data - initialize reiser4 private super block
+ * @super: super block to initialize
+ * @opt_string: list of reiser4 mount options
+ *
+ * Sets various reiser4 parameters to default values. Parses mount options and
+ * overwrites default settings.
+ */
+int reiser4_init_super_data(struct super_block *super, char *opt_string)
+{
+	int result;
+	struct opt_desc *opts, *p;
+	reiser4_super_info_data *sbinfo = get_super_private(super);
+
+	/* initialize super, export, dentry operations */
+	sbinfo->ops.super = reiser4_super_operations;
+	sbinfo->ops.export = reiser4_export_operations;
+	sbinfo->ops.dentry = reiser4_dentry_operations;
+	super->s_op = &sbinfo->ops.super;
+	super->s_export_op = &sbinfo->ops.export;
+
+	/* initialize transaction manager parameters to default values */
+	sbinfo->tmgr.atom_max_size = totalram_pages / 4;
+	sbinfo->tmgr.atom_max_age = REISER4_ATOM_MAX_AGE / HZ;
+	sbinfo->tmgr.atom_min_size = 256;
+	sbinfo->tmgr.atom_max_flushers = ATOM_MAX_FLUSHERS;
+
+	/* initialize cbk cache parameter */
+	sbinfo->tree.cbk_cache.nr_slots = CBK_CACHE_SLOTS;
+
+	/* initialize flush parameters */
+	sbinfo->flush.relocate_threshold = FLUSH_RELOCATE_THRESHOLD;
+	sbinfo->flush.relocate_distance = FLUSH_RELOCATE_DISTANCE;
+	sbinfo->flush.written_threshold = FLUSH_WRITTEN_THRESHOLD;
+	sbinfo->flush.scan_maxnodes = FLUSH_SCAN_MAXNODES;
+
+	sbinfo->optimal_io_size = REISER4_OPTIMAL_IO_SIZE;
+
+	/* preliminary tree initializations */
+	sbinfo->tree.super = super;
+	sbinfo->tree.carry.new_node_flags = REISER4_NEW_NODE_FLAGS;
+	sbinfo->tree.carry.new_extent_flags = REISER4_NEW_EXTENT_FLAGS;
+	sbinfo->tree.carry.paste_flags = REISER4_PASTE_FLAGS;
+	sbinfo->tree.carry.insert_flags = REISER4_INSERT_FLAGS;
+	rwlock_init(&(sbinfo->tree.tree_lock));
+	spin_lock_init(&(sbinfo->tree.epoch_lock));
+
+	/* initialize default readahead params */
+	sbinfo->ra_params.max = num_physpages / 4;
+	sbinfo->ra_params.flags = 0;
+
+	/* allocate memory for structure describing reiser4 mount options */
+	opts = kmalloc(sizeof(struct opt_desc) * MAX_NR_OPTIONS,
+		       reiser4_ctx_gfp_mask_get());
+	if (opts == NULL)
+		return RETERR(-ENOMEM);
+
+	/* initialize structure describing reiser4 mount options */
+	p = opts;
 
+	push_sb_field_opts(p, opts, sbinfo);
 	/* turn on BSD-style gid assignment */
 	PUSH_BIT_OPT("bsdgroups", REISER4_BSD_GID);
 	/* turn on 32 bit times */

Re: [patch 4/4] reiser4: reduce frame size of reiser4_init_super_data

[Laurent Riffard]

Hi Edward,

This patch is buggy, isn't it ?

I've got 2 reiser4 FS in my /etc/fstab:

/dev/vglinux1/lvkernel-r4 /home/laurent/kernel reiser4 defaults,noatime,nodiratime,tmgr.atom_max_size=2048 0 0
/dev/disk/by-uuid/b8dbe880-b664-49aa-8050-bddc91fd5e49 /mnt/diske reiser4 noauto,users,noatime,nodiratime 0 0

The first FS can't be mounted:

[  235.078342] reiser4[mount(4205)]: parse_options (fs/reiser4/init_super.c:253)[nikita-2307]:
[  235.078345] WARNING: Unrecognized option: "tmgr.atom_max_size=2048"

although the second one can be mounted:

[ 3152.046324] reiser4: sda7: found disk format 4.0.0.


Let's have a look at the code in fs/reiser4/init_super.c:


392 int reiser4_init_super_data(struct super_block *super, char *opt_string)
393 {
394         int result;
395         struct opt_desc *opts, *p;
396         reiser4_super_info_data *sbinfo = get_super_private(super);
397 
...
442         p = opts;
443 
444         push_sb_field_opts(p, opts, sbinfo);

p is passed by value to push_sb_field(). push_sb_field() does increment 
its local copy of p, but here p remains equal to opts.

...
501         result = parse_options(opt_string, opts, p - opts);

3rd argument is 0 because p==opts. Now let's have a look at parse_options()

230 static int parse_options(char *opt_string, struct opt_desc *opts, int nr_opts)
231 {

nr_opts always == 0 here.

232         int result;
233
234         result = 0;
235         while ((result == 0) && opt_string && *opt_string) {

I assume opt_string is not null (opt_string == "tmgr.atom_max_size=2048" ?), 
so let's loop:

236                 int j;
237                 char *next;
244                 for (j = 0; j < nr_opts; ++j) {

nr_opts == 0, so we won't do any iteration here.

245                         if (!strncmp(opt_string, opts[j].name,
246                                      strlen(opts[j].name))) {
247                                 result = parse_option(opt_string, &opts[j]);
248                                 break;
249                         }
250                 }

here, j==0 and nr_opts==0.

251                 if (j == nr_opts) {
252                         warning("nikita-2307", "Unrecognized option: \"%s\"",
253                                 opt_string);
254                         /* traditionally, -EINVAL is returned on wrong mount
255                            option */
256                         result = RETERR(-EINVAL);

oops !

~~
laurent

Re: [patch 4/4] reiser4: reduce frame size of reiser4_init_super_data

[Laurent Riffard]

Oops, sorry, Edward already sent a patch for this...

~~
laurent


Le 07/10/2009 21:45, Laurent Riffard a écrit :
> Hi Edward,
> 
> This patch is buggy, isn't it ?
> 
> I've got 2 reiser4 FS in my /etc/fstab:
> 
> /dev/vglinux1/lvkernel-r4 /home/laurent/kernel reiser4 defaults,noatime,nodiratime,tmgr.atom_max_size=2048 0 0
> /dev/disk/by-uuid/b8dbe880-b664-49aa-8050-bddc91fd5e49 /mnt/diske reiser4 noauto,users,noatime,nodiratime 0 0
> 
> The first FS can't be mounted:
> 
> [  235.078342] reiser4[mount(4205)]: parse_options (fs/reiser4/init_super.c:253)[nikita-2307]:
> [  235.078345] WARNING: Unrecognized option: "tmgr.atom_max_size=2048"
> 
> although the second one can be mounted:
> 
> [ 3152.046324] reiser4: sda7: found disk format 4.0.0.
> 
> 
> Let's have a look at the code in fs/reiser4/init_super.c:
> 
> 
> 392 int reiser4_init_super_data(struct super_block *super, char *opt_string)
> 393 {
> 394         int result;
> 395         struct opt_desc *opts, *p;
> 396         reiser4_super_info_data *sbinfo = get_super_private(super);
> 397 
> ...
> 442         p = opts;
> 443 
> 444         push_sb_field_opts(p, opts, sbinfo);
> 
> p is passed by value to push_sb_field(). push_sb_field() does increment 
> its local copy of p, but here p remains equal to opts.
> 
> ...
> 501         result = parse_options(opt_string, opts, p - opts);
> 
> 3rd argument is 0 because p==opts. Now let's have a look at parse_options()
> 
> 230 static int parse_options(char *opt_string, struct opt_desc *opts, int nr_opts)
> 231 {
> 
> nr_opts always == 0 here.
> 
> 232         int result;
> 233
> 234         result = 0;
> 235         while ((result == 0) && opt_string && *opt_string) {
> 
> I assume opt_string is not null (opt_string == "tmgr.atom_max_size=2048" ?), 
> so let's loop:
> 
> 236                 int j;
> 237                 char *next;
> 244                 for (j = 0; j < nr_opts; ++j) {
> 
> nr_opts == 0, so we won't do any iteration here.
> 
> 245                         if (!strncmp(opt_string, opts[j].name,
> 246                                      strlen(opts[j].name))) {
> 247                                 result = parse_option(opt_string, &opts[j]);
> 248                                 break;
> 249                         }
> 250                 }
> 
> here, j==0 and nr_opts==0.
> 
> 251                 if (j == nr_opts) {
> 252                         warning("nikita-2307", "Unrecognized option: \"%s\"",
> 253                                 opt_string);
> 254                         /* traditionally, -EINVAL is returned on wrong mount
> 255                            option */
> 256                         result = RETERR(-EINVAL);
> 
> oops !
> 
> ~~
> laurent
> --
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[patch] reiser4: reduce frame size of reiser4_init_super_data fixup

[Edward Shishkin]

[-- Attachment #1: Type: text/plain, Size: 725 bytes --]

Laurent Riffard wrote:
> Hi Edward,
>   

Hello Laurent.

> This patch is buggy, isn't it ?
>   

Yes, sorry, my fault..
I have sent the fixup already to the list yesterday..
Resending for you and Akpm.
Andrew, please apply.

Thanks.
Edward.

> I've got 2 reiser4 FS in my /etc/fstab:
>
> /dev/vglinux1/lvkernel-r4 /home/laurent/kernel reiser4 defaults,noatime,nodiratime,tmgr.atom_max_size=2048 0 0
> /dev/disk/by-uuid/b8dbe880-b664-49aa-8050-bddc91fd5e49 /mnt/diske reiser4 noauto,users,noatime,nodiratime 0 0
>
> The first FS can't be mounted:
>
> [  235.078342] reiser4[mount(4205)]: parse_options (fs/reiser4/init_super.c:253)[nikita-2307]:
> [  235.078345] WARNING: Unrecognized option: "tmgr.atom_max_size=2048"
>   


[-- Attachment #2: reiser4-reduce-frame-size-fix.patch --]
[-- Type: text/plain, Size: 2644 bytes --]

. Fix up the bug in reiser4_init_super_data():
  The pointer "p" to opt_desc structure is not
  incremented.
  Pass "&p" instead of "p" to push_sb_field_opts(),
  which is supposed to increment the pointer.
. Modify macros PUSH_OPT, OPT_ARRAY_CHECK to accept
  arguments.

Signed-off-by Edward Shsihkin <edward.shishkin@gmail.com>
---
 fs/reiser4/init_super.c |   28 ++++++++++++++++------------
 1 file changed, 16 insertions(+), 12 deletions(-)

--- mmotm.orig/fs/reiser4/init_super.c
+++ mmotm/fs/reiser4/init_super.c
@@ -293,27 +293,27 @@ static int parse_options(char *opt_strin
 #define MAX_NR_OPTIONS (30)
 
 #if REISER4_DEBUG
-#  define OPT_ARRAY_CHECK if ((p) > (opts) + MAX_NR_OPTIONS) {		\
+#  define OPT_ARRAY_CHECK(opt, array)					\
+	if ((opt) > (array) + MAX_NR_OPTIONS) {				\
 		warning("zam-1046", "opt array is overloaded"); break;	\
 	}
 #else
-#   define OPT_ARRAY_CHECK noop
+#   define OPT_ARRAY_CHECK(opt, array) noop
 #endif
 
-#define PUSH_OPT(...)				\
+#define PUSH_OPT(opt, array, ...)		\
 do {						\
 	struct opt_desc o = __VA_ARGS__;	\
-	OPT_ARRAY_CHECK;			\
-	*p ++ = o;				\
+	OPT_ARRAY_CHECK(opt, array);		\
+	*(opt) ++ = o;				\
 } while (0)
 
-#define PUSH_SB_FIELD_OPT(field, format) PUSH_OPT(SB_FIELD_OPT(field, format))
-#define PUSH_BIT_OPT(name, bit) PUSH_OPT(BIT_OPT(name, bit))
-
-static noinline void push_sb_field_opts(struct opt_desc *p,
+static noinline void push_sb_field_opts(struct opt_desc **p,
 					struct opt_desc *opts,
 					reiser4_super_info_data *sbinfo)
 {
+#define PUSH_SB_FIELD_OPT(field, format)		\
+	PUSH_OPT(*p, opts, SB_FIELD_OPT(field, format))
 	/*
 	 * tmgr.atom_max_size=N
 	 * Atoms containing more than N blocks will be forced to commit. N is
@@ -441,8 +441,12 @@ int reiser4_init_super_data(struct super
 	/* initialize structure describing reiser4 mount options */
 	p = opts;
 
-	push_sb_field_opts(p, opts, sbinfo);
+	push_sb_field_opts(&p, opts, sbinfo);
 	/* turn on BSD-style gid assignment */
+
+#define PUSH_BIT_OPT(name, bit)			\
+	PUSH_OPT(p, opts, BIT_OPT(name, bit))
+
 	PUSH_BIT_OPT("bsdgroups", REISER4_BSD_GID);
 	/* turn on 32 bit times */
 	PUSH_BIT_OPT("32bittimes", REISER4_32_BIT_TIMES);
@@ -456,7 +460,7 @@ int reiser4_init_super_data(struct super
 	/* disable use of write barriers in the reiser4 log writer. */
 	PUSH_BIT_OPT("no_write_barrier", REISER4_NO_WRITE_BARRIER);
 
-	PUSH_OPT(
+	PUSH_OPT(p, opts,
 	{
 		/*
 		 * tree traversal readahead parameters:
@@ -482,7 +486,7 @@ int reiser4_init_super_data(struct super
 	);
 
 	/* What to do in case of fs error */
-	PUSH_OPT(
+	PUSH_OPT(p, opts,
 	{
 		.name = "onerror",
 		.type = OPT_ONEOF,