* [PATCH -next v4 1/3] ext4: compare to local seq and nodename when check conflict
2021-10-19 12:39 [PATCH -next v4 0/3] Fix some issues about mmp Ye Bin
@ 2021-10-19 12:39 ` Ye Bin
2021-10-19 12:39 ` [PATCH -next v4 2/3] ext4: remove useless bh_check variable Ye Bin
2021-10-19 12:39 ` [PATCH -next v4 3/3] ext4: simplify read_mmp_block fucntion Ye Bin
2 siblings, 0 replies; 6+ messages in thread
From: Ye Bin @ 2021-10-19 12:39 UTC (permalink / raw)
To: tytso, adilger.kernel, linux-ext4; +Cc: linux-kernel, jack, Ye Bin
As mmp and check_mmp is point to the same data, so there will never
detect conflict.
To solve this issue just compare to local data.
Signed-off-by: Ye Bin <yebin10@huawei.com>
Reviewed-by: Jan Kara <jack@suse.cz>
---
fs/ext4/ext4.h | 5 ++++-
fs/ext4/mmp.c | 9 +++++----
2 files changed, 9 insertions(+), 5 deletions(-)
diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index 404dd50856e5..9a487a558787 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -2601,6 +2601,8 @@ struct ext4_features {
#define EXT4_MMP_SEQ_FSCK 0xE24D4D50U /* mmp_seq value when being fscked */
#define EXT4_MMP_SEQ_MAX 0xE24D4D4FU /* maximum valid mmp_seq value */
+#define EXT4_MMP_NODENAME_LEN 64 /* mmp_nodename length */
+
struct mmp_struct {
__le32 mmp_magic; /* Magic number for MMP */
__le32 mmp_seq; /* Sequence no. updated periodically */
@@ -2610,7 +2612,8 @@ struct mmp_struct {
* purposes and do not affect the correctness of the algorithm
*/
__le64 mmp_time; /* Time last updated */
- char mmp_nodename[64]; /* Node which last updated MMP block */
+ /* Node which last updated MMP block */
+ char mmp_nodename[EXT4_MMP_NODENAME_LEN];
char mmp_bdevname[32]; /* Bdev which last updated MMP block */
/*
diff --git a/fs/ext4/mmp.c b/fs/ext4/mmp.c
index cebea4270817..97d5a8136eb2 100644
--- a/fs/ext4/mmp.c
+++ b/fs/ext4/mmp.c
@@ -138,6 +138,7 @@ static int kmmpd(void *data)
unsigned mmp_check_interval;
unsigned long last_update_time;
unsigned long diff;
+ char nodename[EXT4_MMP_NODENAME_LEN];
int retval = 0;
mmp_block = le64_to_cpu(es->s_mmp_block);
@@ -153,8 +154,8 @@ static int kmmpd(void *data)
BUILD_BUG_ON(sizeof(mmp->mmp_bdevname) < BDEVNAME_SIZE);
bdevname(bh->b_bdev, mmp->mmp_bdevname);
- memcpy(mmp->mmp_nodename, init_utsname()->nodename,
- sizeof(mmp->mmp_nodename));
+ memcpy(nodename, init_utsname()->nodename, sizeof(nodename));
+ memcpy(mmp->mmp_nodename, nodename, sizeof(mmp->mmp_nodename));
while (!kthread_should_stop() && !sb_rdonly(sb)) {
if (!ext4_has_feature_mmp(sb)) {
@@ -206,8 +207,8 @@ static int kmmpd(void *data)
}
mmp_check = (struct mmp_struct *)(bh_check->b_data);
- if (mmp->mmp_seq != mmp_check->mmp_seq ||
- memcmp(mmp->mmp_nodename, mmp_check->mmp_nodename,
+ if (seq != mmp_check->mmp_seq ||
+ memcmp(nodename, mmp_check->mmp_nodename,
sizeof(mmp->mmp_nodename))) {
dump_mmp_msg(sb, mmp_check,
"Error while updating MMP info. "
--
2.31.1
^ permalink raw reply related [flat|nested] 6+ messages in thread
* [PATCH -next v4 2/3] ext4: remove useless bh_check variable
2021-10-19 12:39 [PATCH -next v4 0/3] Fix some issues about mmp Ye Bin
2021-10-19 12:39 ` [PATCH -next v4 1/3] ext4: compare to local seq and nodename when check conflict Ye Bin
@ 2021-10-19 12:39 ` Ye Bin
2021-10-19 12:39 ` [PATCH -next v4 3/3] ext4: simplify read_mmp_block fucntion Ye Bin
2 siblings, 0 replies; 6+ messages in thread
From: Ye Bin @ 2021-10-19 12:39 UTC (permalink / raw)
To: tytso, adilger.kernel, linux-ext4; +Cc: linux-kernel, jack, Ye Bin
Since we initialize 'bh_check' to NULL and pass it to read_mmp_block(), that
function will just call sb_getblk() which will just return the buffer_head
we have in 'bh'. So just remove the pointless 'bh_check' variable and use
'bh' directly.
Signed-off-by: Ye Bin <yebin10@huawei.com>
Reviewed-by: Jan Kara <jack@suse.cz>
---
fs/ext4/mmp.c | 17 ++++++-----------
1 file changed, 6 insertions(+), 11 deletions(-)
diff --git a/fs/ext4/mmp.c b/fs/ext4/mmp.c
index 97d5a8136eb2..9788c617e593 100644
--- a/fs/ext4/mmp.c
+++ b/fs/ext4/mmp.c
@@ -195,10 +195,7 @@ static int kmmpd(void *data)
*/
diff = jiffies - last_update_time;
if (diff > mmp_check_interval * HZ) {
- struct buffer_head *bh_check = NULL;
- struct mmp_struct *mmp_check;
-
- retval = read_mmp_block(sb, &bh_check, mmp_block);
+ retval = read_mmp_block(sb, &bh, mmp_block);
if (retval) {
ext4_error_err(sb, -retval,
"error reading MMP data: %d",
@@ -206,20 +203,18 @@ static int kmmpd(void *data)
goto wait_to_exit;
}
- mmp_check = (struct mmp_struct *)(bh_check->b_data);
- if (seq != mmp_check->mmp_seq ||
- memcmp(nodename, mmp_check->mmp_nodename,
- sizeof(mmp->mmp_nodename))) {
- dump_mmp_msg(sb, mmp_check,
+ mmp = (struct mmp_struct *)(bh->b_data);
+ if (seq != le32_to_cpu(mmp->mmp_seq) ||
+ memcmp(nodename, mmp->mmp_nodename,
+ sizeof(nodename))) {
+ dump_mmp_msg(sb, mmp,
"Error while updating MMP info. "
"The filesystem seems to have been"
" multiply mounted.");
ext4_error_err(sb, EBUSY, "abort");
- put_bh(bh_check);
retval = -EBUSY;
goto wait_to_exit;
}
- put_bh(bh_check);
}
/*
--
2.31.1
^ permalink raw reply related [flat|nested] 6+ messages in thread
* [PATCH -next v4 3/3] ext4: simplify read_mmp_block fucntion
2021-10-19 12:39 [PATCH -next v4 0/3] Fix some issues about mmp Ye Bin
2021-10-19 12:39 ` [PATCH -next v4 1/3] ext4: compare to local seq and nodename when check conflict Ye Bin
2021-10-19 12:39 ` [PATCH -next v4 2/3] ext4: remove useless bh_check variable Ye Bin
@ 2021-10-19 12:39 ` Ye Bin
2021-10-19 13:49 ` Jan Kara
2 siblings, 1 reply; 6+ messages in thread
From: Ye Bin @ 2021-10-19 12:39 UTC (permalink / raw)
To: tytso, adilger.kernel, linux-ext4; +Cc: linux-kernel, jack, Ye Bin
This patch is according to Jan Kara's suggestion:
I guess I would just get rid of sb_getblk() in read_mmp_block() and always
expect valid bh passed. The only place that passes NULL bh after this
patch is one case in ext4_multi_mount_protect() and that can call
sb_getblk() on its own. That way we can also simplify read_mmp_block()
prototype to:
static int read_mmp_block(struct super_block *sb, struct buffer_head *bh);
Signed-off-by: Ye Bin <yebin10@huawei.com>
Reviewed-by: Jan Kara <jack@suse.cz>
---
fs/ext4/mmp.c | 44 +++++++++++++++++++-------------------------
1 file changed, 19 insertions(+), 25 deletions(-)
diff --git a/fs/ext4/mmp.c b/fs/ext4/mmp.c
index 9788c617e593..3a7370c88934 100644
--- a/fs/ext4/mmp.c
+++ b/fs/ext4/mmp.c
@@ -64,33 +64,26 @@ static int write_mmp_block(struct super_block *sb, struct buffer_head *bh)
/*
* Read the MMP block. It _must_ be read from disk and hence we clear the
* uptodate flag on the buffer.
+ * Caller must ensure pass valid 'bh'.
*/
-static int read_mmp_block(struct super_block *sb, struct buffer_head **bh,
- ext4_fsblk_t mmp_block)
+static int read_mmp_block(struct super_block *sb, struct buffer_head *bh)
{
struct mmp_struct *mmp;
int ret;
- if (*bh)
- clear_buffer_uptodate(*bh);
-
- /* This would be sb_bread(sb, mmp_block), except we need to be sure
- * that the MD RAID device cache has been bypassed, and that the read
- * is not blocked in the elevator. */
- if (!*bh) {
- *bh = sb_getblk(sb, mmp_block);
- if (!*bh) {
- ret = -ENOMEM;
- goto warn_exit;
- }
+ if (!bh) {
+ ret = -EINVAL;
+ goto warn_exit;
}
- lock_buffer(*bh);
- ret = ext4_read_bh(*bh, REQ_META | REQ_PRIO, NULL);
+ clear_buffer_uptodate(bh);
+
+ lock_buffer(bh);
+ ret = ext4_read_bh(bh, REQ_META | REQ_PRIO, NULL);
if (ret)
goto warn_exit;
- mmp = (struct mmp_struct *)((*bh)->b_data);
+ mmp = (struct mmp_struct *)((bh)->b_data);
if (le32_to_cpu(mmp->mmp_magic) != EXT4_MMP_MAGIC) {
ret = -EFSCORRUPTED;
goto warn_exit;
@@ -101,10 +94,7 @@ static int read_mmp_block(struct super_block *sb, struct buffer_head **bh,
}
return 0;
warn_exit:
- brelse(*bh);
- *bh = NULL;
- ext4_warning(sb, "Error %d while reading MMP block %llu",
- ret, mmp_block);
+ ext4_warning(sb, "Error %d while reading MMP block", ret);
return ret;
}
@@ -195,7 +185,7 @@ static int kmmpd(void *data)
*/
diff = jiffies - last_update_time;
if (diff > mmp_check_interval * HZ) {
- retval = read_mmp_block(sb, &bh, mmp_block);
+ retval = read_mmp_block(sb, bh);
if (retval) {
ext4_error_err(sb, -retval,
"error reading MMP data: %d",
@@ -289,7 +279,11 @@ int ext4_multi_mount_protect(struct super_block *sb,
goto failed;
}
- retval = read_mmp_block(sb, &bh, mmp_block);
+ bh = sb_getblk(sb, mmp_block);
+ if (bh)
+ goto failed;
+
+ retval = read_mmp_block(sb, bh);
if (retval)
goto failed;
@@ -327,7 +321,7 @@ int ext4_multi_mount_protect(struct super_block *sb,
goto failed;
}
- retval = read_mmp_block(sb, &bh, mmp_block);
+ retval = read_mmp_block(sb, bh);
if (retval)
goto failed;
mmp = (struct mmp_struct *)(bh->b_data);
@@ -356,7 +350,7 @@ int ext4_multi_mount_protect(struct super_block *sb,
goto failed;
}
- retval = read_mmp_block(sb, &bh, mmp_block);
+ retval = read_mmp_block(sb, bh);
if (retval)
goto failed;
mmp = (struct mmp_struct *)(bh->b_data);
--
2.31.1
^ permalink raw reply related [flat|nested] 6+ messages in thread
* Re: [PATCH -next v4 3/3] ext4: simplify read_mmp_block fucntion
2021-10-19 12:39 ` [PATCH -next v4 3/3] ext4: simplify read_mmp_block fucntion Ye Bin
@ 2021-10-19 13:49 ` Jan Kara
2021-10-20 2:53 ` yebin
0 siblings, 1 reply; 6+ messages in thread
From: Jan Kara @ 2021-10-19 13:49 UTC (permalink / raw)
To: Ye Bin; +Cc: tytso, adilger.kernel, linux-ext4, linux-kernel, jack
On Tue 19-10-21 20:39:31, Ye Bin wrote:
> This patch is according to Jan Kara's suggestion:
> I guess I would just get rid of sb_getblk() in read_mmp_block() and always
> expect valid bh passed. The only place that passes NULL bh after this
> patch is one case in ext4_multi_mount_protect() and that can call
> sb_getblk() on its own. That way we can also simplify read_mmp_block()
> prototype to:
>
> static int read_mmp_block(struct super_block *sb, struct buffer_head *bh);
>
> Signed-off-by: Ye Bin <yebin10@huawei.com>
> Reviewed-by: Jan Kara <jack@suse.cz>
...
> @@ -289,7 +279,11 @@ int ext4_multi_mount_protect(struct super_block *sb,
> goto failed;
> }
>
> - retval = read_mmp_block(sb, &bh, mmp_block);
> + bh = sb_getblk(sb, mmp_block);
> + if (bh)
^^^^^^
!bh here, please.
Honza
--
Jan Kara <jack@suse.com>
SUSE Labs, CR
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH -next v4 3/3] ext4: simplify read_mmp_block fucntion
2021-10-19 13:49 ` Jan Kara
@ 2021-10-20 2:53 ` yebin
0 siblings, 0 replies; 6+ messages in thread
From: yebin @ 2021-10-20 2:53 UTC (permalink / raw)
To: Jan Kara; +Cc: tytso, adilger.kernel, linux-ext4, linux-kernel
On 2021/10/19 21:49, Jan Kara wrote:
> On Tue 19-10-21 20:39:31, Ye Bin wrote:
>> This patch is according to Jan Kara's suggestion:
>> I guess I would just get rid of sb_getblk() in read_mmp_block() and always
>> expect valid bh passed. The only place that passes NULL bh after this
>> patch is one case in ext4_multi_mount_protect() and that can call
>> sb_getblk() on its own. That way we can also simplify read_mmp_block()
>> prototype to:
>>
>> static int read_mmp_block(struct super_block *sb, struct buffer_head *bh);
>>
>> Signed-off-by: Ye Bin <yebin10@huawei.com>
>> Reviewed-by: Jan Kara <jack@suse.cz>
> ...
>
>> @@ -289,7 +279,11 @@ int ext4_multi_mount_protect(struct super_block *sb,
>> goto failed;
>> }
>>
>> - retval = read_mmp_block(sb, &bh, mmp_block);
>> + bh = sb_getblk(sb, mmp_block);
>> + if (bh)
> ^^^^^^
>
> !bh here, please.
Sorry,it's my fault. I will fix it and test this patch set base on
linux mainline.
>
> Honza
>
^ permalink raw reply [flat|nested] 6+ messages in thread