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ext4: update delalloc data reserve spcae in ext4_es_insert_extent()

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Now that we update data reserved space for delalloc after allocating
new blocks in ext4_{ind|ext}_map_blocks(), and if bigalloc feature is
enabled, we also need to query the extents_status tree to calculate the
exact reserved clusters. This is complicated now and it appears that
it's better to do this job in ext4_es_insert_extent(), because
__es_remove_extent() have already count delalloc blocks when removing
delalloc extents and __revise_pending() return new adding pending count,
we could update the reserved blocks easily in ext4_es_insert_extent().

We direct reduce the reserved cluster count when replacing a delalloc
extent. However, thers are two special cases need to concern about the
quota claiming when doing direct block allocation (e.g. from fallocate).

A),
fallocate a range that covers a delalloc extent but start with
non-delayed allocated blocks, e.g. a hole.

  hhhhhhh+ddddddd+ddddddd
  ^^^^^^^^^^^^^^^^^^^^^^^  fallocate this range

Current ext4_map_blocks() can't always trim the extent since it may
release i_data_sem before calling ext4_map_create_blocks() and raced by
another delayed allocation. Hence the EXT4_GET_BLOCKS_DELALLOC_RESERVE
may not set even when we are replacing a delalloc extent, without this
flag set, the quota has already been claimed by ext4_mb_new_blocks(), so
we should release the quota reservations instead of claim them again.

B),
bigalloc feature is enabled, fallocate a range that contains non-delayed
allocated blocks.

  |<         one cluster       >|
  hhhhhhh+hhhhhhh+hhhhhhh+ddddddd
  ^^^^^^^  fallocate this range

This case is similar to above case, the EXT4_GET_BLOCKS_DELALLOC_RESERVE
flag is also not set.

Hence we should release the quota reservations if we replace a delalloc
extent but without EXT4_GET_BLOCKS_DELALLOC_RESERVE set.

Signed-off-by: Zhang Yi <yi.zhang@huawei.com>
Link: https://patch.msgid.link/20240813123452.2824659-7-yi.zhang@huaweicloud.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
This commit is contained in:
Zhang Yi 2024-08-13 20:34:46 +08:00 committed by Theodore Ts'o
parent f3baf33b9c
commit c543e24296
3 changed files with 24 additions and 45 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

37
fs/ext4/extents.c
View File

@ -4357,43 +4357,6 @@ got_allocated_blocks:
goto out;
}
/*
* Reduce the reserved cluster count to reflect successful deferred
* allocation of delayed allocated clusters or direct allocation of
* clusters discovered to be delayed allocated. Once allocated, a
* cluster is not included in the reserved count.
*/
if (test_opt(inode->i_sb, DELALLOC) && allocated_clusters) {
if (flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE) {
/*
* When allocating delayed allocated clusters, simply
* reduce the reserved cluster count and claim quota
*/
ext4_da_update_reserve_space(inode, allocated_clusters,
1);
} else {
ext4_lblk_t lblk, len;
unsigned int n;
/*
* When allocating non-delayed allocated clusters
* (from fallocate, filemap, DIO, or clusters
* allocated when delalloc has been disabled by
* ext4_nonda_switch), reduce the reserved cluster
* count by the number of allocated clusters that
* have previously been delayed allocated. Quota
* has been claimed by ext4_mb_new_blocks() above,
* so release the quota reservations made for any
* previously delayed allocated clusters.
*/
lblk = EXT4_LBLK_CMASK(sbi, map->m_lblk);
len = allocated_clusters << sbi->s_cluster_bits;
n = ext4_es_delayed_clu(inode, lblk, len);
if (n > 0)
ext4_da_update_reserve_space(inode, (int) n, 0);
}
}
/*
* Cache the extent and update transaction to commit on fdatasync only
* when it is _not_ an unwritten extent.

25
fs/ext4/extents_status.c
View File

@ -853,6 +853,7 @@ void ext4_es_insert_extent(struct inode *inode, ext4_lblk_t lblk,
struct extent_status newes;
ext4_lblk_t end = lblk + len - 1;
int err1 = 0, err2 = 0, err3 = 0;
int resv_used = 0, pending = 0;
struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
struct extent_status *es1 = NULL;
struct extent_status *es2 = NULL;
@ -891,7 +892,7 @@ retry:
pr = __alloc_pending(true);
write_lock(&EXT4_I(inode)->i_es_lock);
err1 = __es_remove_extent(inode, lblk, end, NULL, es1);
err1 = __es_remove_extent(inode, lblk, end, &resv_used, es1);
if (err1 != 0)
goto error;
/* Free preallocated extent if it didn't get used. */
@ -921,9 +922,31 @@ retry:
__free_pending(pr);
pr = NULL;
}
pending = err3;
}
error:
write_unlock(&EXT4_I(inode)->i_es_lock);
/*
* Reduce the reserved cluster count to reflect successful deferred
* allocation of delayed allocated clusters or direct allocation of
* clusters discovered to be delayed allocated. Once allocated, a
* cluster is not included in the reserved count.
*
* When direct allocating (from fallocate, filemap, DIO, or clusters
* allocated when delalloc has been disabled by ext4_nonda_switch())
* an extent either 1) contains delayed blocks but start with
* non-delayed allocated blocks (e.g. hole) or 2) contains non-delayed
* allocated blocks which belong to delayed allocated clusters when
* bigalloc feature is enabled, quota has already been claimed by
* ext4_mb_new_blocks(), so release the quota reservations made for
* any previously delayed allocated clusters instead of claim them
* again.
*/
resv_used += pending;
if (resv_used)
ext4_da_update_reserve_space(inode, resv_used,
flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE);
if (err1 || err2 || err3 < 0)
goto retry;

7
fs/ext4/indirect.c
View File

@ -652,13 +652,6 @@ int ext4_ind_map_blocks(handle_t *handle, struct inode *inode,
ext4_update_inode_fsync_trans(handle, inode, 1);
count = ar.len;
/*
* Update reserved blocks/metadata blocks after successful block
* allocation which had been deferred till now.
*/
if (flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE)
ext4_da_update_reserve_space(inode, count, 1);
got_it:
map->m_flags |= EXT4_MAP_MAPPED;
map->m_pblk = le32_to_cpu(chain[depth-1].key);