2023-08-24 09:49:46

by Zhang Yi

[permalink] [raw]
Subject: [RFC PATCH 10/16] ext4: reserve meta blocks in ext4_da_reserve_space()

From: Zhang Yi <[email protected]>

Prepare to reserve metadata blocks for delay allocation in
ext4_da_reserve_space(), claim reserved space from the global
sbi->s_dirtyclusters_counter, and also updating tracepoints to show the
new reserved metadata blocks. This patch is just a preparation, the
reserved ext_len is always zero.

Signed-off-by: Zhang Yi <[email protected]>
---
fs/ext4/inode.c | 28 ++++++++++++++++------------
include/trace/events/ext4.h | 10 ++++++++--
2 files changed, 24 insertions(+), 14 deletions(-)

diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index dda17b3340ce..a189009d20fa 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -1439,31 +1439,37 @@ static int ext4_journalled_write_end(struct file *file,
}

/*
- * Reserve space for a single cluster
+ * Reserve space for a 'rsv_dlen' data blocks/clusters and 'rsv_extlen'
+ * extent metadata blocks.
*/
-static int ext4_da_reserve_space(struct inode *inode)
+static int ext4_da_reserve_space(struct inode *inode, unsigned int rsv_dlen,
+ unsigned int rsv_extlen)
{
struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
struct ext4_inode_info *ei = EXT4_I(inode);
int ret;

+ if (!rsv_dlen && !rsv_extlen)
+ return 0;
+
/*
* We will charge metadata quota at writeout time; this saves
* us from metadata over-estimation, though we may go over by
* a small amount in the end. Here we just reserve for data.
*/
- ret = dquot_reserve_block(inode, EXT4_C2B(sbi, 1));
+ ret = dquot_reserve_block(inode, EXT4_C2B(sbi, rsv_dlen));
if (ret)
return ret;

spin_lock(&ei->i_block_reservation_lock);
- if (ext4_claim_free_clusters(sbi, 1, 0)) {
+ if (ext4_claim_free_clusters(sbi, rsv_dlen + rsv_extlen, 0)) {
spin_unlock(&ei->i_block_reservation_lock);
- dquot_release_reservation_block(inode, EXT4_C2B(sbi, 1));
+ dquot_release_reservation_block(inode, EXT4_C2B(sbi, rsv_dlen));
return -ENOSPC;
}
- ei->i_reserved_data_blocks++;
- trace_ext4_da_reserve_space(inode);
+ ei->i_reserved_data_blocks += rsv_dlen;
+ ei->i_reserved_ext_blocks += rsv_extlen;
+ trace_ext4_da_reserve_space(inode, rsv_dlen, rsv_extlen);
spin_unlock(&ei->i_block_reservation_lock);

return 0; /* success */
@@ -1659,11 +1665,9 @@ static int ext4_insert_delayed_block(struct inode *inode, ext4_lblk_t lblk)
}
}

- if (rsv_dlen > 0) {
- ret = ext4_da_reserve_space(inode);
- if (ret) /* ENOSPC */
- return ret;
- }
+ ret = ext4_da_reserve_space(inode, rsv_dlen, 0);
+ if (ret) /* ENOSPC */
+ return ret;

ext4_es_insert_delayed_block(inode, lblk, allocated);
return 0;
diff --git a/include/trace/events/ext4.h b/include/trace/events/ext4.h
index 115f96f444ff..7a9839f2d681 100644
--- a/include/trace/events/ext4.h
+++ b/include/trace/events/ext4.h
@@ -1251,14 +1251,16 @@ TRACE_EVENT(ext4_da_update_reserve_space,
);

TRACE_EVENT(ext4_da_reserve_space,
- TP_PROTO(struct inode *inode),
+ TP_PROTO(struct inode *inode, int data_blocks, int meta_blocks),

- TP_ARGS(inode),
+ TP_ARGS(inode, data_blocks, meta_blocks),

TP_STRUCT__entry(
__field( dev_t, dev )
__field( ino_t, ino )
__field( __u64, i_blocks )
+ __field( int, data_blocks )
+ __field( int, meta_blocks )
__field( int, reserved_data_blocks )
__field( int, reserved_ext_blocks )
__field( __u16, mode )
@@ -1268,16 +1270,20 @@ TRACE_EVENT(ext4_da_reserve_space,
__entry->dev = inode->i_sb->s_dev;
__entry->ino = inode->i_ino;
__entry->i_blocks = inode->i_blocks;
+ __entry->data_blocks = data_blocks;
+ __entry->meta_blocks = meta_blocks;
__entry->reserved_data_blocks = EXT4_I(inode)->i_reserved_data_blocks;
__entry->reserved_ext_blocks = EXT4_I(inode)->i_reserved_ext_blocks;
__entry->mode = inode->i_mode;
),

TP_printk("dev %d,%d ino %lu mode 0%o i_blocks %llu "
+ "data_blocks %d meta_blocks %d "
"reserved_data_blocks %d reserved_ext_blocks %d",
MAJOR(__entry->dev), MINOR(__entry->dev),
(unsigned long) __entry->ino,
__entry->mode, __entry->i_blocks,
+ __entry->data_blocks, __entry->meta_blocks,
__entry->reserved_data_blocks,
__entry->reserved_ext_blocks)
);
--
2.39.2