[RFC PATCH v4 21/34] ext4: introduce seq counter for the extent status entry

Zhang Yi
2024-04-10T14:38:42Z

Add a modify counter for the extent status entry, which indicates the
version of extent status of one inode, increase it once extent changes.
It it a preparation for the conversion of the regular file's buffered
write path from bh to iomap.

Signed-off-by: Zhang Yi <yi.zhang@huawei.com>
---
fs/ext4/ext4.h | 1 +
fs/ext4/extents_status.c | 13 ++++++++++++-
fs/ext4/super.c | 1 +
include/trace/events/ext4.h | 20 ++++++++++++++------
4 files changed, 28 insertions(+), 7 deletions(-)

diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index 8d126654019e..7e27e1e7c579 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -1115,6 +1115,7 @@ struct ext4_inode_info {
ext4_lblk_t i_es_shrink_lblk; /* Offset where we start searching for
extents to shrink. Protected by
i_es_lock */
+ unsigned int i_es_seq; /* modify counter for extents */

/* ialloc */
ext4_group_t i_last_alloc_group;
diff --git a/fs/ext4/extents_status.c b/fs/ext4/extents_status.c
index 926669d8eb3e..90b58cf42cdd 100644
--- a/fs/ext4/extents_status.c
+++ b/fs/ext4/extents_status.c
@@ -209,6 +209,13 @@ static inline ext4_lblk_t ext4_es_end(struct extent_status *es)
return es->es_lblk + es->es_len - 1;
}

+static inline void ext4_es_inc_seq(struct inode *inode)
+{
+ struct ext4_inode_info *ei = EXT4_I(inode);
+
+ WRITE_ONCE(ei->i_es_seq, READ_ONCE(ei->i_es_seq) + 1);
+}
+
/*
* search through the tree for an delayed extent with a given offset. If
* it can't be found, try to find next extent.
@@ -876,6 +883,7 @@ void ext4_es_insert_extent(struct inode *inode, ext4_lblk_t lblk,
BUG_ON(end < lblk);
WARN_ON_ONCE(status & EXTENT_STATUS_DELAYED);

+ ext4_es_inc_seq(inode);
newes.es_lblk = lblk;
newes.es_len = len;
ext4_es_store_pblock_status(&newes, pblk, status);
@@ -1530,13 +1538,15 @@ void ext4_es_remove_extent(struct inode *inode, ext4_lblk_t lblk,
if (EXT4_SB(inode->i_sb)->s_mount_state & EXT4_FC_REPLAY)
return;

- trace_ext4_es_remove_extent(inode, lblk, len);
es_debug("remove [%u/%u) from extent status tree of inode %lu\n",
lblk, len, inode->i_ino);

if (!len)
return;

+ ext4_es_inc_seq(inode);
+ trace_ext4_es_remove_extent(inode, lblk, len);
+
end = lblk + len - 1;
BUG_ON(end < lblk);

@@ -2111,6 +2121,7 @@ void ext4_es_insert_delayed_extent(struct inode *inode, ext4_lblk_t lblk,
if (!len)
return;

+ ext4_es_inc_seq(inode);
newes.es_lblk = lblk;
newes.es_len = len;
ext4_es_store_pblock_status(&newes, ~0, EXTENT_STATUS_DELAYED);
diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index 044135796f2b..5fce4d2b3b87 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -1421,6 +1421,7 @@ static struct inode *ext4_alloc_inode(struct super_block *sb)
ei->i_es_all_nr = 0;
ei->i_es_shk_nr = 0;
ei->i_es_shrink_lblk = 0;
+ ei->i_es_seq = 0;
ei->i_reserved_data_blocks = 0;
spin_lock_init(&(ei->i_block_reservation_lock));
ext4_init_pending_tree(&ei->i_pending_tree);
diff --git a/include/trace/events/ext4.h b/include/trace/events/ext4.h
index cc5e9b7b2b44..4d583d0248d9 100644
--- a/include/trace/events/ext4.h
+++ b/include/trace/events/ext4.h
@@ -2183,6 +2183,7 @@ DECLARE_EVENT_CLASS(ext4__es_extent,
__field( ext4_lblk_t, len )
__field( ext4_fsblk_t, pblk )
__field( char, status )
+ __field( unsigned int, seq )
),

TP_fast_assign(
@@ -2192,13 +2193,15 @@ DECLARE_EVENT_CLASS(ext4__es_extent,
__entry->len = es->es_len;
__entry->pblk = ext4_es_show_pblock(es);
__entry->status = ext4_es_status(es);
+ __entry->seq = EXT4_I(inode)->i_es_seq;
),

- TP_printk("dev %d,%d ino %lu es [%u/%u) mapped %llu status %s",
+ TP_printk("dev %d,%d ino %lu es [%u/%u) mapped %llu status %s seq %u",
MAJOR(__entry->dev), MINOR(__entry->dev),
(unsigned long) __entry->ino,
__entry->lblk, __entry->len,
- __entry->pblk, show_extent_status(__entry->status))
+ __entry->pblk, show_extent_status(__entry->status),
+ __entry->seq)
);

DEFINE_EVENT(ext4__es_extent, ext4_es_insert_extent,
@@ -2223,6 +2226,7 @@ TRACE_EVENT(ext4_es_remove_extent,
__field( ino_t, ino )
__field( loff_t, lblk )
__field( loff_t, len )
+ __field( unsigned int, seq )
),

TP_fast_assign(
@@ -2230,12 +2234,13 @@ TRACE_EVENT(ext4_es_remove_extent,
__entry->ino = inode->i_ino;
__entry->lblk = lblk;
__entry->len = len;
+ __entry->seq = EXT4_I(inode)->i_es_seq;
),

- TP_printk("dev %d,%d ino %lu es [%lld/%lld)",
+ TP_printk("dev %d,%d ino %lu es [%lld/%lld) seq %u",
MAJOR(__entry->dev), MINOR(__entry->dev),
(unsigned long) __entry->ino,
- __entry->lblk, __entry->len)
+ __entry->lblk, __entry->len, __entry->seq)
);

TRACE_EVENT(ext4_es_find_extent_range_enter,
@@ -2495,6 +2500,7 @@ TRACE_EVENT(ext4_es_insert_delayed_extent,
__field( char, status )
__field( bool, lclu_allocated )
__field( bool, end_allocated )
+ __field( unsigned int, seq )
),

TP_fast_assign(
@@ -2506,15 +2512,17 @@ TRACE_EVENT(ext4_es_insert_delayed_extent,
__entry->status = ext4_es_status(es);
__entry->lclu_allocated = lclu_allocated;
__entry->end_allocated = end_allocated;
+ __entry->seq = EXT4_I(inode)->i_es_seq;
),

TP_printk("dev %d,%d ino %lu es [%u/%u) mapped %llu status %s "
- "allocated %d %d",
+ "allocated %d %d seq %u",
MAJOR(__entry->dev), MINOR(__entry->dev),
(unsigned long) __entry->ino,
__entry->lblk, __entry->len,
__entry->pblk, show_extent_status(__entry->status),
- __entry->lclu_allocated, __entry->end_allocated)
+ __entry->lclu_allocated, __entry->end_allocated,
+ __entry->seq)
);

/* fsmap traces */
--
2.39.2