From 102a0743326a03cd1a1202ceda21e175b7d3575c Mon Sep 17 00:00:00 2001
From: hc <hc@nodka.com>
Date: Tue, 20 Feb 2024 01:20:52 +0000
Subject: [PATCH] add new system file
---
kernel/fs/ext4/mmp.c | 123 +++++++++++++++++++++++------------------
1 files changed, 69 insertions(+), 54 deletions(-)
diff --git a/kernel/fs/ext4/mmp.c b/kernel/fs/ext4/mmp.c
index 9d00e0d..7a9a8ed 100644
--- a/kernel/fs/ext4/mmp.c
+++ b/kernel/fs/ext4/mmp.c
@@ -39,26 +39,34 @@
* Write the MMP block using REQ_SYNC to try to get the block on-disk
* faster.
*/
-static int write_mmp_block(struct super_block *sb, struct buffer_head *bh)
+static int write_mmp_block_thawed(struct super_block *sb,
+ struct buffer_head *bh)
{
struct mmp_struct *mmp = (struct mmp_struct *)(bh->b_data);
- /*
- * We protect against freezing so that we don't create dirty buffers
- * on frozen filesystem.
- */
- sb_start_write(sb);
ext4_mmp_csum_set(sb, mmp);
lock_buffer(bh);
bh->b_end_io = end_buffer_write_sync;
get_bh(bh);
submit_bh(REQ_OP_WRITE, REQ_SYNC | REQ_META | REQ_PRIO, bh);
wait_on_buffer(bh);
- sb_end_write(sb);
if (unlikely(!buffer_uptodate(bh)))
- return 1;
-
+ return -EIO;
return 0;
+}
+
+static int write_mmp_block(struct super_block *sb, struct buffer_head *bh)
+{
+ int err;
+
+ /*
+ * We protect against freezing so that we don't create dirty buffers
+ * on frozen filesystem.
+ */
+ sb_start_write(sb);
+ err = write_mmp_block_thawed(sb, bh);
+ sb_end_write(sb);
+ return err;
}
/*
@@ -85,15 +93,11 @@
}
}
- get_bh(*bh);
lock_buffer(*bh);
- (*bh)->b_end_io = end_buffer_read_sync;
- submit_bh(REQ_OP_READ, REQ_META | REQ_PRIO, *bh);
- wait_on_buffer(*bh);
- if (!buffer_uptodate(*bh)) {
- ret = -EIO;
+ ret = ext4_read_bh(*bh, REQ_META | REQ_PRIO, NULL);
+ if (ret)
goto warn_exit;
- }
+
mmp = (struct mmp_struct *)((*bh)->b_data);
if (le32_to_cpu(mmp->mmp_magic) != EXT4_MMP_MAGIC) {
ret = -EFSCORRUPTED;
@@ -131,9 +135,9 @@
*/
static int kmmpd(void *data)
{
- struct super_block *sb = ((struct mmpd_data *) data)->sb;
- struct buffer_head *bh = ((struct mmpd_data *) data)->bh;
+ struct super_block *sb = (struct super_block *) data;
struct ext4_super_block *es = EXT4_SB(sb)->s_es;
+ struct buffer_head *bh = EXT4_SB(sb)->s_mmp_bh;
struct mmp_struct *mmp;
ext4_fsblk_t mmp_block;
u32 seq = 0;
@@ -160,7 +164,12 @@
memcpy(mmp->mmp_nodename, init_utsname()->nodename,
sizeof(mmp->mmp_nodename));
- while (!kthread_should_stop()) {
+ while (!kthread_should_stop() && !sb_rdonly(sb)) {
+ if (!ext4_has_feature_mmp(sb)) {
+ ext4_warning(sb, "kmmpd being stopped since MMP feature"
+ " has been disabled.");
+ goto wait_to_exit;
+ }
if (++seq > EXT4_MMP_SEQ_MAX)
seq = 1;
@@ -174,20 +183,12 @@
* (s_mmp_update_interval * 60) seconds.
*/
if (retval) {
- if ((failed_writes % 60) == 0)
- ext4_error(sb, "Error writing to MMP block");
+ if ((failed_writes % 60) == 0) {
+ ext4_error_err(sb, -retval,
+ "Error writing to MMP block");
+ }
failed_writes++;
}
-
- if (!(le32_to_cpu(es->s_feature_incompat) &
- EXT4_FEATURE_INCOMPAT_MMP)) {
- ext4_warning(sb, "kmmpd being stopped since MMP feature"
- " has been disabled.");
- goto exit_thread;
- }
-
- if (sb_rdonly(sb))
- break;
diff = jiffies - last_update_time;
if (diff < mmp_update_interval * HZ)
@@ -206,9 +207,10 @@
retval = read_mmp_block(sb, &bh_check, mmp_block);
if (retval) {
- ext4_error(sb, "error reading MMP data: %d",
- retval);
- goto exit_thread;
+ ext4_error_err(sb, -retval,
+ "error reading MMP data: %d",
+ retval);
+ goto wait_to_exit;
}
mmp_check = (struct mmp_struct *)(bh_check->b_data);
@@ -219,10 +221,10 @@
"Error while updating MMP info. "
"The filesystem seems to have been"
" multiply mounted.");
- ext4_error(sb, "abort");
+ ext4_error_err(sb, EBUSY, "abort");
put_bh(bh_check);
retval = -EBUSY;
- goto exit_thread;
+ goto wait_to_exit;
}
put_bh(bh_check);
}
@@ -245,11 +247,23 @@
retval = write_mmp_block(sb, bh);
-exit_thread:
- EXT4_SB(sb)->s_mmp_tsk = NULL;
- kfree(data);
- brelse(bh);
+wait_to_exit:
+ while (!kthread_should_stop()) {
+ set_current_state(TASK_INTERRUPTIBLE);
+ if (!kthread_should_stop())
+ schedule();
+ }
+ set_current_state(TASK_RUNNING);
return retval;
+}
+
+void ext4_stop_mmpd(struct ext4_sb_info *sbi)
+{
+ if (sbi->s_mmp_tsk) {
+ kthread_stop(sbi->s_mmp_tsk);
+ brelse(sbi->s_mmp_bh);
+ sbi->s_mmp_tsk = NULL;
+ }
}
/*
@@ -276,7 +290,6 @@
struct ext4_super_block *es = EXT4_SB(sb)->s_es;
struct buffer_head *bh = NULL;
struct mmp_struct *mmp = NULL;
- struct mmpd_data *mmpd_data;
u32 seq;
unsigned int mmp_check_interval = le16_to_cpu(es->s_mmp_update_interval);
unsigned int wait_time = 0;
@@ -285,6 +298,7 @@
if (mmp_block < le32_to_cpu(es->s_first_data_block) ||
mmp_block >= ext4_blocks_count(es)) {
ext4_warning(sb, "Invalid MMP block in superblock");
+ retval = -EINVAL;
goto failed;
}
@@ -310,6 +324,7 @@
if (seq == EXT4_MMP_SEQ_FSCK) {
dump_mmp_msg(sb, mmp, "fsck is running on the filesystem");
+ retval = -EBUSY;
goto failed;
}
@@ -323,6 +338,7 @@
if (schedule_timeout_interruptible(HZ * wait_time) != 0) {
ext4_warning(sb, "MMP startup interrupted, failing mount\n");
+ retval = -ETIMEDOUT;
goto failed;
}
@@ -333,6 +349,7 @@
if (seq != le32_to_cpu(mmp->mmp_seq)) {
dump_mmp_msg(sb, mmp,
"Device is already active on another node.");
+ retval = -EBUSY;
goto failed;
}
@@ -343,7 +360,11 @@
seq = mmp_new_seq();
mmp->mmp_seq = cpu_to_le32(seq);
- retval = write_mmp_block(sb, bh);
+ /*
+ * On mount / remount we are protected against fs freezing (by s_umount
+ * semaphore) and grabbing freeze protection upsets lockdep
+ */
+ retval = write_mmp_block_thawed(sb, bh);
if (retval)
goto failed;
@@ -352,6 +373,7 @@
*/
if (schedule_timeout_interruptible(HZ * wait_time) != 0) {
ext4_warning(sb, "MMP startup interrupted, failing mount");
+ retval = -ETIMEDOUT;
goto failed;
}
@@ -362,29 +384,24 @@
if (seq != le32_to_cpu(mmp->mmp_seq)) {
dump_mmp_msg(sb, mmp,
"Device is already active on another node.");
+ retval = -EBUSY;
goto failed;
}
- mmpd_data = kmalloc(sizeof(*mmpd_data), GFP_KERNEL);
- if (!mmpd_data) {
- ext4_warning(sb, "not enough memory for mmpd_data");
- goto failed;
- }
- mmpd_data->sb = sb;
- mmpd_data->bh = bh;
+ EXT4_SB(sb)->s_mmp_bh = bh;
/*
* Start a kernel thread to update the MMP block periodically.
*/
- EXT4_SB(sb)->s_mmp_tsk = kthread_run(kmmpd, mmpd_data, "kmmpd-%.*s",
+ EXT4_SB(sb)->s_mmp_tsk = kthread_run(kmmpd, sb, "kmmpd-%.*s",
(int)sizeof(mmp->mmp_bdevname),
bdevname(bh->b_bdev,
mmp->mmp_bdevname));
if (IS_ERR(EXT4_SB(sb)->s_mmp_tsk)) {
EXT4_SB(sb)->s_mmp_tsk = NULL;
- kfree(mmpd_data);
ext4_warning(sb, "Unable to create kmmpd thread for %s.",
sb->s_id);
+ retval = -ENOMEM;
goto failed;
}
@@ -392,7 +409,5 @@
failed:
brelse(bh);
- return 1;
+ return retval;
}
-
-
--
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