2019-01-10 13:54:07

by Andy Shevchenko

[permalink] [raw]
Subject: [PATCH v1] fs/jfs: Switch to use new generic UUID API

There are new types and helpers that are supposed to be used in new code.

As a preparation to get rid of legacy types and API functions do
the conversion here.

Signed-off-by: Andy Shevchenko <[email protected]>
---

- not tested on real FS

fs/jfs/jfs_incore.h | 6 ++++--
fs/jfs/jfs_logmgr.c | 17 ++++++++---------
fs/jfs/jfs_logmgr.h | 10 +++++-----
fs/jfs/jfs_mount.c | 4 ++--
fs/jfs/jfs_superblock.h | 7 ++++---
fs/jfs/super.c | 5 +++--
6 files changed, 26 insertions(+), 23 deletions(-)

diff --git a/fs/jfs/jfs_incore.h b/fs/jfs/jfs_incore.h
index 912a3af2393e..340eb8e4f716 100644
--- a/fs/jfs/jfs_incore.h
+++ b/fs/jfs/jfs_incore.h
@@ -23,6 +23,8 @@
#include <linux/rwsem.h>
#include <linux/slab.h>
#include <linux/bitops.h>
+#include <linux/uuid.h>
+
#include "jfs_types.h"
#include "jfs_xtree.h"
#include "jfs_dtree.h"
@@ -178,8 +180,8 @@ struct jfs_sb_info {
pxd_t logpxd; /* pxd describing log */
pxd_t fsckpxd; /* pxd describing fsck wkspc */
pxd_t ait2; /* pxd describing AIT copy */
- char uuid[16]; /* 128-bit uuid for volume */
- char loguuid[16]; /* 128-bit uuid for log */
+ uuid_t uuid; /* 128-bit uuid for volume */
+ uuid_t loguuid; /* 128-bit uuid for log */
/*
* commit_state is used for synchronization of the jfs_commit
* threads. It is protected by LAZY_LOCK().
diff --git a/fs/jfs/jfs_logmgr.c b/fs/jfs/jfs_logmgr.c
index 6b68df395892..6361fa4d85db 100644
--- a/fs/jfs/jfs_logmgr.c
+++ b/fs/jfs/jfs_logmgr.c
@@ -1092,8 +1092,7 @@ int lmLogOpen(struct super_block *sb)
mutex_lock(&jfs_log_mutex);
list_for_each_entry(log, &jfs_external_logs, journal_list) {
if (log->bdev->bd_dev == sbi->logdev) {
- if (memcmp(log->uuid, sbi->loguuid,
- sizeof(log->uuid))) {
+ if (!uuid_equal(&log->uuid, &sbi->loguuid)) {
jfs_warn("wrong uuid on JFS journal");
mutex_unlock(&jfs_log_mutex);
return -EINVAL;
@@ -1130,7 +1129,7 @@ int lmLogOpen(struct super_block *sb)
}

log->bdev = bdev;
- memcpy(log->uuid, sbi->loguuid, sizeof(log->uuid));
+ uuid_copy(&log->uuid, &sbi->loguuid);

/*
* initialize log:
@@ -1336,7 +1335,7 @@ int lmLogInit(struct jfs_log * log)
jfs_info("lmLogInit: inline log:0x%p base:0x%Lx size:0x%x",
log, (unsigned long long)log->base, log->size);
} else {
- if (memcmp(logsuper->uuid, log->uuid, 16)) {
+ if (!uuid_equal(&logsuper->uuid, &log->uuid)) {
jfs_warn("wrong uuid on JFS log device");
goto errout20;
}
@@ -1732,7 +1731,7 @@ static int lmLogFileSystem(struct jfs_log * log, struct jfs_sb_info *sbi,
int i;
struct logsuper *logsuper;
struct lbuf *bpsuper;
- char *uuid = sbi->uuid;
+ uuid_t *uuid = &sbi->uuid;

/*
* insert/remove file system device to log active file system list.
@@ -1743,8 +1742,8 @@ static int lmLogFileSystem(struct jfs_log * log, struct jfs_sb_info *sbi,
logsuper = (struct logsuper *) bpsuper->l_ldata;
if (activate) {
for (i = 0; i < MAX_ACTIVE; i++)
- if (!memcmp(logsuper->active[i].uuid, NULL_UUID, 16)) {
- memcpy(logsuper->active[i].uuid, uuid, 16);
+ if (uuid_is_null(&logsuper->active[i].uuid)) {
+ uuid_copy(&logsuper->active[i].uuid, uuid);
sbi->aggregate = i;
break;
}
@@ -1755,8 +1754,8 @@ static int lmLogFileSystem(struct jfs_log * log, struct jfs_sb_info *sbi,
}
} else {
for (i = 0; i < MAX_ACTIVE; i++)
- if (!memcmp(logsuper->active[i].uuid, uuid, 16)) {
- memcpy(logsuper->active[i].uuid, NULL_UUID, 16);
+ if (uuid_equal(&logsuper->active[i].uuid, uuid)) {
+ uuid_copy(&logsuper->active[i].uuid, &uuid_null);
break;
}
if (i == MAX_ACTIVE) {
diff --git a/fs/jfs/jfs_logmgr.h b/fs/jfs/jfs_logmgr.h
index e38c21598850..870fc22360e7 100644
--- a/fs/jfs/jfs_logmgr.h
+++ b/fs/jfs/jfs_logmgr.h
@@ -19,6 +19,8 @@
#ifndef _H_JFS_LOGMGR
#define _H_JFS_LOGMGR

+#include <linux/uuid.h>
+
#include "jfs_filsys.h"
#include "jfs_lock.h"

@@ -73,15 +75,13 @@ struct logsuper {
__le32 state; /* 4: state - see below */

__le32 end; /* 4: addr of last log record set by logredo */
- char uuid[16]; /* 16: 128-bit journal uuid */
+ uuid_t uuid; /* 16: 128-bit journal uuid */
char label[16]; /* 16: journal label */
struct {
- char uuid[16];
+ uuid_t uuid;
} active[MAX_ACTIVE]; /* 2048: active file systems list */
};

-#define NULL_UUID "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"
-
/* log flag: commit option (see jfs_filsys.h) */

/* log state */
@@ -410,7 +410,7 @@ struct jfs_log {
spinlock_t synclock; /* 4: synclist lock */
struct lbuf *wqueue; /* 4: log pageout queue */
int count; /* 4: count */
- char uuid[16]; /* 16: 128-bit uuid of log device */
+ uuid_t uuid; /* 16: 128-bit uuid of log device */

int no_integrity; /* 3: flag to disable journaling to disk */
};
diff --git a/fs/jfs/jfs_mount.c b/fs/jfs/jfs_mount.c
index d8658607bf46..c9c1f16b93df 100644
--- a/fs/jfs/jfs_mount.c
+++ b/fs/jfs/jfs_mount.c
@@ -389,8 +389,8 @@ static int chkSuper(struct super_block *sb)
sbi->logpxd = j_sb->s_logpxd;
else {
sbi->logdev = new_decode_dev(le32_to_cpu(j_sb->s_logdev));
- memcpy(sbi->uuid, j_sb->s_uuid, sizeof(sbi->uuid));
- memcpy(sbi->loguuid, j_sb->s_loguuid, sizeof(sbi->uuid));
+ uuid_copy(&sbi->uuid, &j_sb->s_uuid);
+ uuid_copy(&sbi->loguuid, &j_sb->s_loguuid);
}
sbi->fsckpxd = j_sb->s_fsckpxd;
sbi->ait2 = j_sb->s_ait2;
diff --git a/fs/jfs/jfs_superblock.h b/fs/jfs/jfs_superblock.h
index 04847b8d3070..0a401f083d1a 100644
--- a/fs/jfs/jfs_superblock.h
+++ b/fs/jfs/jfs_superblock.h
@@ -18,6 +18,8 @@
#ifndef _H_JFS_SUPERBLOCK
#define _H_JFS_SUPERBLOCK

+#include <linux/uuid.h>
+
/*
* make the magic number something a human could read
*/
@@ -100,10 +102,9 @@ struct jfs_superblock {
pxd_t s_xlogpxd; /* 8: extendfs logpxd */
/* - 128 byte boundary - */

- char s_uuid[16]; /* 16: 128-bit uuid for volume */
+ uuid_t s_uuid; /* 16: 128-bit uuid for volume */
char s_label[16]; /* 16: volume label */
- char s_loguuid[16]; /* 16: 128-bit uuid for log device */
-
+ uuid_t s_loguuid; /* 16: 128-bit uuid for log device */
};

extern int readSuper(struct super_block *, struct buffer_head **);
diff --git a/fs/jfs/super.c b/fs/jfs/super.c
index 65d8fc87ab11..99a43e7f6ee0 100644
--- a/fs/jfs/super.c
+++ b/fs/jfs/super.c
@@ -174,8 +174,9 @@ static int jfs_statfs(struct dentry *dentry, struct kstatfs *buf)
buf->f_files = maxinodes;
buf->f_ffree = maxinodes - (atomic_read(&imap->im_numinos) -
atomic_read(&imap->im_numfree));
- buf->f_fsid.val[0] = (u32)crc32_le(0, sbi->uuid, sizeof(sbi->uuid)/2);
- buf->f_fsid.val[1] = (u32)crc32_le(0, sbi->uuid + sizeof(sbi->uuid)/2,
+ buf->f_fsid.val[0] = (u32)crc32_le(0, (char *)&sbi->uuid,
+ sizeof(sbi->uuid)/2);
+ buf->f_fsid.val[1] = (u32)crc32_le(0, (char *)&sbi->uuid + sizeof(sbi->uuid)/2,
sizeof(sbi->uuid)/2);

buf->f_namelen = JFS_NAME_MAX;
--
2.20.1



2019-01-10 17:00:51

by Dave Kleikamp

[permalink] [raw]
Subject: Re: [PATCH v1] fs/jfs: Switch to use new generic UUID API

On 1/10/19 7:41 AM, Andy Shevchenko wrote:
> There are new types and helpers that are supposed to be used in new code.
>
> As a preparation to get rid of legacy types and API functions do
> the conversion here.

Looks good to me. I tweaked it slightly to keep checkpatch from
complaining about lines over 80 characters. I'll push it into -next for
v5.1.

Shaggy

>
> Signed-off-by: Andy Shevchenko <[email protected]>
> ---
>
> - not tested on real FS
>
> fs/jfs/jfs_incore.h | 6 ++++--
> fs/jfs/jfs_logmgr.c | 17 ++++++++---------
> fs/jfs/jfs_logmgr.h | 10 +++++-----
> fs/jfs/jfs_mount.c | 4 ++--
> fs/jfs/jfs_superblock.h | 7 ++++---
> fs/jfs/super.c | 5 +++--
> 6 files changed, 26 insertions(+), 23 deletions(-)
>
> diff --git a/fs/jfs/jfs_incore.h b/fs/jfs/jfs_incore.h
> index 912a3af2393e..340eb8e4f716 100644
> --- a/fs/jfs/jfs_incore.h
> +++ b/fs/jfs/jfs_incore.h
> @@ -23,6 +23,8 @@
> #include <linux/rwsem.h>
> #include <linux/slab.h>
> #include <linux/bitops.h>
> +#include <linux/uuid.h>
> +
> #include "jfs_types.h"
> #include "jfs_xtree.h"
> #include "jfs_dtree.h"
> @@ -178,8 +180,8 @@ struct jfs_sb_info {
> pxd_t logpxd; /* pxd describing log */
> pxd_t fsckpxd; /* pxd describing fsck wkspc */
> pxd_t ait2; /* pxd describing AIT copy */
> - char uuid[16]; /* 128-bit uuid for volume */
> - char loguuid[16]; /* 128-bit uuid for log */
> + uuid_t uuid; /* 128-bit uuid for volume */
> + uuid_t loguuid; /* 128-bit uuid for log */
> /*
> * commit_state is used for synchronization of the jfs_commit
> * threads. It is protected by LAZY_LOCK().
> diff --git a/fs/jfs/jfs_logmgr.c b/fs/jfs/jfs_logmgr.c
> index 6b68df395892..6361fa4d85db 100644
> --- a/fs/jfs/jfs_logmgr.c
> +++ b/fs/jfs/jfs_logmgr.c
> @@ -1092,8 +1092,7 @@ int lmLogOpen(struct super_block *sb)
> mutex_lock(&jfs_log_mutex);
> list_for_each_entry(log, &jfs_external_logs, journal_list) {
> if (log->bdev->bd_dev == sbi->logdev) {
> - if (memcmp(log->uuid, sbi->loguuid,
> - sizeof(log->uuid))) {
> + if (!uuid_equal(&log->uuid, &sbi->loguuid)) {
> jfs_warn("wrong uuid on JFS journal");
> mutex_unlock(&jfs_log_mutex);
> return -EINVAL;
> @@ -1130,7 +1129,7 @@ int lmLogOpen(struct super_block *sb)
> }
>
> log->bdev = bdev;
> - memcpy(log->uuid, sbi->loguuid, sizeof(log->uuid));
> + uuid_copy(&log->uuid, &sbi->loguuid);
>
> /*
> * initialize log:
> @@ -1336,7 +1335,7 @@ int lmLogInit(struct jfs_log * log)
> jfs_info("lmLogInit: inline log:0x%p base:0x%Lx size:0x%x",
> log, (unsigned long long)log->base, log->size);
> } else {
> - if (memcmp(logsuper->uuid, log->uuid, 16)) {
> + if (!uuid_equal(&logsuper->uuid, &log->uuid)) {
> jfs_warn("wrong uuid on JFS log device");
> goto errout20;
> }
> @@ -1732,7 +1731,7 @@ static int lmLogFileSystem(struct jfs_log * log, struct jfs_sb_info *sbi,
> int i;
> struct logsuper *logsuper;
> struct lbuf *bpsuper;
> - char *uuid = sbi->uuid;
> + uuid_t *uuid = &sbi->uuid;
>
> /*
> * insert/remove file system device to log active file system list.
> @@ -1743,8 +1742,8 @@ static int lmLogFileSystem(struct jfs_log * log, struct jfs_sb_info *sbi,
> logsuper = (struct logsuper *) bpsuper->l_ldata;
> if (activate) {
> for (i = 0; i < MAX_ACTIVE; i++)
> - if (!memcmp(logsuper->active[i].uuid, NULL_UUID, 16)) {
> - memcpy(logsuper->active[i].uuid, uuid, 16);
> + if (uuid_is_null(&logsuper->active[i].uuid)) {
> + uuid_copy(&logsuper->active[i].uuid, uuid);
> sbi->aggregate = i;
> break;
> }
> @@ -1755,8 +1754,8 @@ static int lmLogFileSystem(struct jfs_log * log, struct jfs_sb_info *sbi,
> }
> } else {
> for (i = 0; i < MAX_ACTIVE; i++)
> - if (!memcmp(logsuper->active[i].uuid, uuid, 16)) {
> - memcpy(logsuper->active[i].uuid, NULL_UUID, 16);
> + if (uuid_equal(&logsuper->active[i].uuid, uuid)) {
> + uuid_copy(&logsuper->active[i].uuid, &uuid_null);
> break;
> }
> if (i == MAX_ACTIVE) {
> diff --git a/fs/jfs/jfs_logmgr.h b/fs/jfs/jfs_logmgr.h
> index e38c21598850..870fc22360e7 100644
> --- a/fs/jfs/jfs_logmgr.h
> +++ b/fs/jfs/jfs_logmgr.h
> @@ -19,6 +19,8 @@
> #ifndef _H_JFS_LOGMGR
> #define _H_JFS_LOGMGR
>
> +#include <linux/uuid.h>
> +
> #include "jfs_filsys.h"
> #include "jfs_lock.h"
>
> @@ -73,15 +75,13 @@ struct logsuper {
> __le32 state; /* 4: state - see below */
>
> __le32 end; /* 4: addr of last log record set by logredo */
> - char uuid[16]; /* 16: 128-bit journal uuid */
> + uuid_t uuid; /* 16: 128-bit journal uuid */
> char label[16]; /* 16: journal label */
> struct {
> - char uuid[16];
> + uuid_t uuid;
> } active[MAX_ACTIVE]; /* 2048: active file systems list */
> };
>
> -#define NULL_UUID "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"
> -
> /* log flag: commit option (see jfs_filsys.h) */
>
> /* log state */
> @@ -410,7 +410,7 @@ struct jfs_log {
> spinlock_t synclock; /* 4: synclist lock */
> struct lbuf *wqueue; /* 4: log pageout queue */
> int count; /* 4: count */
> - char uuid[16]; /* 16: 128-bit uuid of log device */
> + uuid_t uuid; /* 16: 128-bit uuid of log device */
>
> int no_integrity; /* 3: flag to disable journaling to disk */
> };
> diff --git a/fs/jfs/jfs_mount.c b/fs/jfs/jfs_mount.c
> index d8658607bf46..c9c1f16b93df 100644
> --- a/fs/jfs/jfs_mount.c
> +++ b/fs/jfs/jfs_mount.c
> @@ -389,8 +389,8 @@ static int chkSuper(struct super_block *sb)
> sbi->logpxd = j_sb->s_logpxd;
> else {
> sbi->logdev = new_decode_dev(le32_to_cpu(j_sb->s_logdev));
> - memcpy(sbi->uuid, j_sb->s_uuid, sizeof(sbi->uuid));
> - memcpy(sbi->loguuid, j_sb->s_loguuid, sizeof(sbi->uuid));
> + uuid_copy(&sbi->uuid, &j_sb->s_uuid);
> + uuid_copy(&sbi->loguuid, &j_sb->s_loguuid);
> }
> sbi->fsckpxd = j_sb->s_fsckpxd;
> sbi->ait2 = j_sb->s_ait2;
> diff --git a/fs/jfs/jfs_superblock.h b/fs/jfs/jfs_superblock.h
> index 04847b8d3070..0a401f083d1a 100644
> --- a/fs/jfs/jfs_superblock.h
> +++ b/fs/jfs/jfs_superblock.h
> @@ -18,6 +18,8 @@
> #ifndef _H_JFS_SUPERBLOCK
> #define _H_JFS_SUPERBLOCK
>
> +#include <linux/uuid.h>
> +
> /*
> * make the magic number something a human could read
> */
> @@ -100,10 +102,9 @@ struct jfs_superblock {
> pxd_t s_xlogpxd; /* 8: extendfs logpxd */
> /* - 128 byte boundary - */
>
> - char s_uuid[16]; /* 16: 128-bit uuid for volume */
> + uuid_t s_uuid; /* 16: 128-bit uuid for volume */
> char s_label[16]; /* 16: volume label */
> - char s_loguuid[16]; /* 16: 128-bit uuid for log device */
> -
> + uuid_t s_loguuid; /* 16: 128-bit uuid for log device */
> };
>
> extern int readSuper(struct super_block *, struct buffer_head **);
> diff --git a/fs/jfs/super.c b/fs/jfs/super.c
> index 65d8fc87ab11..99a43e7f6ee0 100644
> --- a/fs/jfs/super.c
> +++ b/fs/jfs/super.c
> @@ -174,8 +174,9 @@ static int jfs_statfs(struct dentry *dentry, struct kstatfs *buf)
> buf->f_files = maxinodes;
> buf->f_ffree = maxinodes - (atomic_read(&imap->im_numinos) -
> atomic_read(&imap->im_numfree));
> - buf->f_fsid.val[0] = (u32)crc32_le(0, sbi->uuid, sizeof(sbi->uuid)/2);
> - buf->f_fsid.val[1] = (u32)crc32_le(0, sbi->uuid + sizeof(sbi->uuid)/2,
> + buf->f_fsid.val[0] = (u32)crc32_le(0, (char *)&sbi->uuid,
> + sizeof(sbi->uuid)/2);
> + buf->f_fsid.val[1] = (u32)crc32_le(0, (char *)&sbi->uuid + sizeof(sbi->uuid)/2,
> sizeof(sbi->uuid)/2);
>
> buf->f_namelen = JFS_NAME_MAX;
>

2019-01-21 08:57:27

by Christoph Hellwig

[permalink] [raw]
Subject: Re: [PATCH v1] fs/jfs: Switch to use new generic UUID API

> + buf->f_fsid.val[1] = (u32)crc32_le(0, (char *)&sbi->uuid + sizeof(sbi->uuid)/2,

This adds an overly long line, and has weird operator spacing.

In fact given how much deep magic it does it should probably be moved
into a helper and properly documented when you touch it anyway.

2019-01-21 16:21:01

by Dave Kleikamp

[permalink] [raw]
Subject: Re: [PATCH v1] fs/jfs: Switch to use new generic UUID API

On 1/21/19 2:49 AM, Christoph Hellwig wrote:
>> + buf->f_fsid.val[1] = (u32)crc32_le(0, (char *)&sbi->uuid + sizeof(sbi->uuid)/2,
>
> This adds an overly long line, and has weird operator spacing.
>
> In fact given how much deep magic it does it should probably be moved
> into a helper and properly documented when you touch it anyway.
>

I cleaned this up a bit when I pushed it to the jfs tree.

https://github.com/kleikamp/linux-shaggy/commit/2e3bc6125154c691e987e2554f2c99ec10f83b73

Here's the relevant part. It's still a bit ugly, but I got rid of an
unnecessary cast and kept the lines from exceeding 80 characters.

diff --git a/fs/jfs/super.c b/fs/jfs/super.c
index 65d8fc87ab11..c15ff56a8516 100644
--- a/fs/jfs/super.c
+++ b/fs/jfs/super.c
@@ -174,9 +174,11 @@ static int jfs_statfs(struct dentry *dentry, struct kstatfs *buf)
buf->f_files = maxinodes;
buf->f_ffree = maxinodes - (atomic_read(&imap->im_numinos) -
atomic_read(&imap->im_numfree));
- buf->f_fsid.val[0] = (u32)crc32_le(0, sbi->uuid, sizeof(sbi->uuid)/2);
- buf->f_fsid.val[1] = (u32)crc32_le(0, sbi->uuid + sizeof(sbi->uuid)/2,
- sizeof(sbi->uuid)/2);
+ buf->f_fsid.val[0] = crc32_le(0, (char *)&sbi->uuid,
+ sizeof(sbi->uuid)/2);
+ buf->f_fsid.val[1] = crc32_le(0,
+ (char *)&sbi->uuid + sizeof(sbi->uuid)/2,
+ sizeof(sbi->uuid)/2);

buf->f_namelen = JFS_NAME_MAX;
return 0;

2019-01-21 16:25:21

by Christoph Hellwig

[permalink] [raw]
Subject: Re: [PATCH v1] fs/jfs: Switch to use new generic UUID API

On Mon, Jan 21, 2019 at 10:19:15AM -0600, Dave Kleikamp wrote:
> diff --git a/fs/jfs/super.c b/fs/jfs/super.c
> index 65d8fc87ab11..c15ff56a8516 100644
> --- a/fs/jfs/super.c
> +++ b/fs/jfs/super.c
> @@ -174,9 +174,11 @@ static int jfs_statfs(struct dentry *dentry, struct kstatfs *buf)
> buf->f_files = maxinodes;
> buf->f_ffree = maxinodes - (atomic_read(&imap->im_numinos) -
> atomic_read(&imap->im_numfree));
> - buf->f_fsid.val[0] = (u32)crc32_le(0, sbi->uuid, sizeof(sbi->uuid)/2);
> - buf->f_fsid.val[1] = (u32)crc32_le(0, sbi->uuid + sizeof(sbi->uuid)/2,
> - sizeof(sbi->uuid)/2);
> + buf->f_fsid.val[0] = crc32_le(0, (char *)&sbi->uuid,
> + sizeof(sbi->uuid)/2);
> + buf->f_fsid.val[1] = crc32_le(0,
> + (char *)&sbi->uuid + sizeof(sbi->uuid)/2,
> + sizeof(sbi->uuid)/2);

I'd really love to see a little helper to calculate the fsid, and
a comment on that function documenting the design decision behind it.

2019-01-21 17:48:26

by Dave Kleikamp

[permalink] [raw]
Subject: Re: [PATCH v1] fs/jfs: Switch to use new generic UUID API

On 1/21/19 10:23 AM, Christoph Hellwig wrote:
> On Mon, Jan 21, 2019 at 10:19:15AM -0600, Dave Kleikamp wrote:
>> diff --git a/fs/jfs/super.c b/fs/jfs/super.c
>> index 65d8fc87ab11..c15ff56a8516 100644
>> --- a/fs/jfs/super.c
>> +++ b/fs/jfs/super.c
>> @@ -174,9 +174,11 @@ static int jfs_statfs(struct dentry *dentry, struct kstatfs *buf)
>> buf->f_files = maxinodes;
>> buf->f_ffree = maxinodes - (atomic_read(&imap->im_numinos) -
>> atomic_read(&imap->im_numfree));
>> - buf->f_fsid.val[0] = (u32)crc32_le(0, sbi->uuid, sizeof(sbi->uuid)/2);
>> - buf->f_fsid.val[1] = (u32)crc32_le(0, sbi->uuid + sizeof(sbi->uuid)/2,
>> - sizeof(sbi->uuid)/2);
>> + buf->f_fsid.val[0] = crc32_le(0, (char *)&sbi->uuid,
>> + sizeof(sbi->uuid)/2);
>> + buf->f_fsid.val[1] = crc32_le(0,
>> + (char *)&sbi->uuid + sizeof(sbi->uuid)/2,
>> + sizeof(sbi->uuid)/2);
>
> I'd really love to see a little helper to calculate the fsid, and
> a comment on that function documenting the design decision behind it.

I can do that. It was a long time ago, but I'm sure the design decision
was that I took the idea from another filesystem, possibly reiserfs, but
I'll make a better case than that. :-)

Shaggy