From: Harshad Shirwadkar <[email protected]>
Convert ext4_inode_info->i_fc_lock to spinlock to avoid sleeping
in invalid contexts.
Signed-off-by: Harshad Shirwadkar <[email protected]>
---
fs/ext4/ext4.h | 7 +++++--
fs/ext4/fast_commit.c | 28 +++++++++++++++-------------
fs/ext4/super.c | 2 +-
3 files changed, 21 insertions(+), 16 deletions(-)
diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index 3f87cca49f0c..fb6d65f1176f 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -1065,8 +1065,11 @@ struct ext4_inode_info {
/* Fast commit wait queue for this inode */
wait_queue_head_t i_fc_wait;
- /* Protect concurrent accesses on i_fc_lblk_start, i_fc_lblk_len */
- struct mutex i_fc_lock;
+ /*
+ * Protect concurrent accesses on i_fc_lblk_start, i_fc_lblk_len
+ * and inode's EXT4_FC_STATE_COMMITTING state bit.
+ */
+ spinlock_t i_fc_lock;
/*
* i_disksize keeps track of what the inode size is ON DISK, not
diff --git a/fs/ext4/fast_commit.c b/fs/ext4/fast_commit.c
index 5ac594e03402..9913de655b61 100644
--- a/fs/ext4/fast_commit.c
+++ b/fs/ext4/fast_commit.c
@@ -387,7 +387,7 @@ static int ext4_fc_track_template(
return -EINVAL;
tid = handle->h_transaction->t_tid;
- mutex_lock(&ei->i_fc_lock);
+ spin_lock(&ei->i_fc_lock);
if (tid == ei->i_sync_tid) {
update = true;
} else {
@@ -395,7 +395,7 @@ static int ext4_fc_track_template(
ei->i_sync_tid = tid;
}
ret = __fc_track_fn(inode, args, update);
- mutex_unlock(&ei->i_fc_lock);
+ spin_unlock(&ei->i_fc_lock);
if (!enqueue)
return ret;
@@ -427,11 +427,11 @@ static int __track_dentry_update(struct inode *inode, void *arg, bool update)
struct dentry *dentry = dentry_update->dentry;
struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
- mutex_unlock(&ei->i_fc_lock);
+ spin_unlock(&ei->i_fc_lock);
node = kmem_cache_alloc(ext4_fc_dentry_cachep, GFP_NOFS);
if (!node) {
ext4_fc_mark_ineligible(inode->i_sb, EXT4_FC_REASON_NOMEM, NULL);
- mutex_lock(&ei->i_fc_lock);
+ spin_lock(&ei->i_fc_lock);
return -ENOMEM;
}
@@ -444,7 +444,7 @@ static int __track_dentry_update(struct inode *inode, void *arg, bool update)
kmem_cache_free(ext4_fc_dentry_cachep, node);
ext4_fc_mark_ineligible(inode->i_sb,
EXT4_FC_REASON_NOMEM, NULL);
- mutex_lock(&ei->i_fc_lock);
+ spin_lock(&ei->i_fc_lock);
return -ENOMEM;
}
memcpy((u8 *)node->fcd_name.name, dentry->d_name.name,
@@ -478,7 +478,7 @@ static int __track_dentry_update(struct inode *inode, void *arg, bool update)
list_add_tail(&node->fcd_dilist, &ei->i_fc_dilist);
}
spin_unlock(&sbi->s_fc_lock);
- mutex_lock(&ei->i_fc_lock);
+ spin_lock(&ei->i_fc_lock);
return 0;
}
@@ -580,10 +580,8 @@ static int __track_range(struct inode *inode, void *arg, bool update)
struct __track_range_args *__arg =
(struct __track_range_args *)arg;
- if (inode->i_ino < EXT4_FIRST_INO(inode->i_sb)) {
- ext4_debug("Special inode %ld being modified\n", inode->i_ino);
+ if (inode->i_ino < EXT4_FIRST_INO(inode->i_sb))
return -ECANCELED;
- }
oldstart = ei->i_fc_lblk_start;
@@ -867,15 +865,15 @@ static int ext4_fc_write_inode_data(struct inode *inode, u32 *crc)
struct ext4_extent *ex;
int ret;
- mutex_lock(&ei->i_fc_lock);
+ spin_lock(&ei->i_fc_lock);
if (ei->i_fc_lblk_len == 0) {
- mutex_unlock(&ei->i_fc_lock);
+ spin_unlock(&ei->i_fc_lock);
return 0;
}
old_blk_size = ei->i_fc_lblk_start;
new_blk_size = ei->i_fc_lblk_start + ei->i_fc_lblk_len - 1;
ei->i_fc_lblk_len = 0;
- mutex_unlock(&ei->i_fc_lock);
+ spin_unlock(&ei->i_fc_lock);
cur_lblk_off = old_blk_size;
jbd_debug(1, "%s: will try writing %d to %d for inode %ld\n",
@@ -972,9 +970,13 @@ static int ext4_fc_wait_inode_data_all(journal_t *journal)
spin_lock(&sbi->s_fc_lock);
list_for_each_entry_safe(pos, n, &sbi->s_fc_q[FC_Q_MAIN], i_fc_list) {
+ spin_lock(&pos->i_fc_lock);
if (!ext4_test_inode_state(&pos->vfs_inode,
- EXT4_STATE_FC_COMMITTING))
+ EXT4_STATE_FC_COMMITTING)) {
+ spin_unlock(&pos->i_fc_lock);
continue;
+ }
+ spin_unlock(&pos->i_fc_lock);
spin_unlock(&sbi->s_fc_lock);
ret = jbd2_wait_inode_data(journal, pos->jinode);
diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index 1e5f4994fe57..38d63113c383 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -1346,7 +1346,7 @@ static struct inode *ext4_alloc_inode(struct super_block *sb)
atomic_set(&ei->i_unwritten, 0);
INIT_WORK(&ei->i_rsv_conversion_work, ext4_end_io_rsv_work);
ext4_fc_init_inode(&ei->vfs_inode);
- mutex_init(&ei->i_fc_lock);
+ spin_lock_init(&ei->i_fc_lock);
return &ei->vfs_inode;
}
--
2.35.1.616.g0bdcbb4464-goog
On Tue 08-03-22 08:33:15, Harshad Shirwadkar wrote:
> From: Harshad Shirwadkar <[email protected]>
>
> Convert ext4_inode_info->i_fc_lock to spinlock to avoid sleeping
> in invalid contexts.
>
> Signed-off-by: Harshad Shirwadkar <[email protected]>
One comment below...
> @@ -972,9 +970,13 @@ static int ext4_fc_wait_inode_data_all(journal_t *journal)
>
> spin_lock(&sbi->s_fc_lock);
> list_for_each_entry_safe(pos, n, &sbi->s_fc_q[FC_Q_MAIN], i_fc_list) {
> + spin_lock(&pos->i_fc_lock);
> if (!ext4_test_inode_state(&pos->vfs_inode,
> - EXT4_STATE_FC_COMMITTING))
> + EXT4_STATE_FC_COMMITTING)) {
> + spin_unlock(&pos->i_fc_lock);
> continue;
> + }
> + spin_unlock(&pos->i_fc_lock);
> spin_unlock(&sbi->s_fc_lock);
Why do you add a lock here in a pure lock-conversion patch? Furthermore I
don't think the lock is needed...
Honza
--
Jan Kara <[email protected]>
SUSE Labs, CR
On Wed, 9 Mar 2022 at 02:10, Jan Kara <[email protected]> wrote:
>
> On Tue 08-03-22 08:33:15, Harshad Shirwadkar wrote:
> > From: Harshad Shirwadkar <[email protected]>
> >
> > Convert ext4_inode_info->i_fc_lock to spinlock to avoid sleeping
> > in invalid contexts.
> >
> > Signed-off-by: Harshad Shirwadkar <[email protected]>
>
> One comment below...
>
> > @@ -972,9 +970,13 @@ static int ext4_fc_wait_inode_data_all(journal_t *journal)
> >
> > spin_lock(&sbi->s_fc_lock);
> > list_for_each_entry_safe(pos, n, &sbi->s_fc_q[FC_Q_MAIN], i_fc_list) {
> > + spin_lock(&pos->i_fc_lock);
> > if (!ext4_test_inode_state(&pos->vfs_inode,
> > - EXT4_STATE_FC_COMMITTING))
> > + EXT4_STATE_FC_COMMITTING)) {
> > + spin_unlock(&pos->i_fc_lock);
> > continue;
> > + }
> > + spin_unlock(&pos->i_fc_lock);
> > spin_unlock(&sbi->s_fc_lock);
>
> Why do you add a lock here in a pure lock-conversion patch? Furthermore I
> don't think the lock is needed...
Oops sorry, this was an unintentional leftover from the first version,
I'll remove it in the next one, thanks!
- Harshad
>
> Honza
> --
> Jan Kara <[email protected]>
> SUSE Labs, CR
Hi Harshad Shirwadkar,
...
>@@ -427,11 +427,11 @@ static int __track_dentry_update(struct inode *inode, void *arg, bool update)
> struct dentry *dentry = dentry_update->dentry;
> struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
>
>- mutex_unlock(&ei->i_fc_lock);
>+ spin_unlock(&ei->i_fc_lock);
> node = kmem_cache_alloc(ext4_fc_dentry_cachep, GFP_NOFS);
Is it sleep-safe with spinlock?
> if (!node) {
> ext4_fc_mark_ineligible(inode->i_sb, EXT4_FC_REASON_NOMEM, NULL);
>- mutex_lock(&ei->i_fc_lock);
>+ spin_lock(&ei->i_fc_lock);
> return -ENOMEM;
> }
>
Thanks,
Daejun