On 8/18/25 11:51, 王晓珺 wrote:
> Hi Chao,
>
> The combination of truncate and falloc complicates the recovery process.
>
> For example, in the following scenario:
>
> write fileA 2M | fsync | truncate 256K | falloc -k 256K 1M | fsync A | SPO
> The falloc (256K, 1M) need to be recovered as pre-allocated space.
>
> But in the following scenarios, the situation is the opposite.
>
> write fileA 2M | fsync | falloc -k 2M 10M | fsync A | truncate 256K |
> fsync A | SPO
> In this scenario, the space allocated by falloc needs to be truncated.
> In fact, the current f2fs cannot reclaim this part of the space.
>
> During the recovery process, it is difficult to distinguish
> between the above two types of falloc.
>
> I think that when a file is truncated, a FI_TRUNC_FILE flag should be
> setted.
> When the file is fsync'd, if the FI_TRUNC_FILE flag is present,
> a checkpoint needs to be performed.
truncate to small size and fsync would be a common case, it's better
to not trigger checkpoint during fsync.
What do you think of triggering checkpoint for fsync after falloc -k ...
instead? IMO, it shouldn't be a common case in Android.
Thanks,
>
> Thanks,
>
> On 8/11/2025 10:54 AM, Wang Xiaojun wrote:
>> Hi Chao,
>>
>> This patch will cause falloc to fail in the following scenarios.
>> write fileA 2M | fsync | truncate 256K | falloc -k 256K 1M | fsync A
>> | SPO
>> So I will fix this issue in the next version of the patch.
>>
>> Thanks,
>>
>> On 8/8/2025 12:16 PM, Chao Yu wrote:
>>> Xiaojun,
>>>
>>> I just notice generic/483 will fail w/ this change, can you please
>>> take a
>>> look?
>>>
>>> Thanks,
>>>
>>> On 8/7/2025 4:44 PM, Wang Xiaojun wrote:
>>>> This patch fixes missing space reclamation during the recovery process.
>>>> In the following scenarios, F2FS cannot reclaim truncated space.
>>>> case 1:
>>>> write file A, size is 1G | CP | truncate A to 1M | fsync A | SPO
>>>>
>>>> case 2:
>>>> CP | write file A, size is 1G | fsync A | truncate A to 1M | fsync A
>>>> |SPO
>>>>
>>>> During the recovery process, F2FS will recover file A,
>>>> but the 1M-1G space cannot be reclaimed.
>>>>
>>>> Fixes: d624c96fb3249 ("f2fs: add recovery routines for roll-forward")
>>>>
>>>> Signed-off-by: Wang Xiaojun <[email protected]>
>>>> ---
>>>> v3: Add a Fixes line.
>>>> v2: Apply Chao's suggestion from v1. No logical changes.
>>>> v1: Fix missing space reclamation during the recovery process.
>>>> ---
>>>> fs/f2fs/f2fs.h | 1 +
>>>> fs/f2fs/recovery.c | 18 +++++++++++++++++-
>>>> 2 files changed, 18 insertions(+), 1 deletion(-)
>>>>
>>>> diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
>>>> index 46be7560548c..28fce59198ce 100644
>>>> --- a/fs/f2fs/f2fs.h
>>>> +++ b/fs/f2fs/f2fs.h
>>>> @@ -459,6 +459,7 @@ struct fsync_inode_entry {
>>>> struct inode *inode; /* vfs inode pointer */
>>>> block_t blkaddr; /* block address locating the last fsync */
>>>> block_t last_dentry; /* block address locating the last
>>>> dentry */
>>>> + loff_t max_i_size; /* previous max file size for truncate */
>>>> };
>>>> #define nats_in_cursum(jnl) (le16_to_cpu((jnl)->n_nats))
>>>> diff --git a/fs/f2fs/recovery.c b/fs/f2fs/recovery.c
>>>> index 4cb3a91801b4..68b62c8a74d3 100644
>>>> --- a/fs/f2fs/recovery.c
>>>> +++ b/fs/f2fs/recovery.c
>>>> @@ -95,6 +95,7 @@ static struct fsync_inode_entry
>>>> *add_fsync_inode(struct f2fs_sb_info *sbi,
>>>> entry = f2fs_kmem_cache_alloc(fsync_entry_slab,
>>>> GFP_F2FS_ZERO, true, NULL);
>>>> entry->inode = inode;
>>>> + entry->max_i_size = i_size_read(inode);
>>>> list_add_tail(&entry->list, head);
>>>> return entry;
>>>> @@ -796,6 +797,7 @@ static int recover_data(struct f2fs_sb_info
>>>> *sbi, struct list_head *inode_list,
>>>> while (1) {
>>>> struct fsync_inode_entry *entry;
>>>> struct folio *folio;
>>>> + loff_t i_size;
>>>> if (!f2fs_is_valid_blkaddr(sbi, blkaddr, META_POR))
>>>> break;
>>>> @@ -828,6 +830,9 @@ static int recover_data(struct f2fs_sb_info
>>>> *sbi, struct list_head *inode_list,
>>>> break;
>>>> }
>>>> recovered_inode++;
>>>> + i_size = i_size_read(entry->inode);
>>>> + if (entry->max_i_size < i_size)
>>>> + entry->max_i_size = i_size;
>>>> }
>>>> if (entry->last_dentry == blkaddr) {
>>>> err = recover_dentry(entry->inode, folio, dir_list);
>>>> @@ -844,8 +849,19 @@ static int recover_data(struct f2fs_sb_info
>>>> *sbi, struct list_head *inode_list,
>>>> }
>>>> recovered_dnode++;
>>>> - if (entry->blkaddr == blkaddr)
>>>> + if (entry->blkaddr == blkaddr) {
>>>> + i_size = i_size_read(entry->inode);
>>>> + if (entry->max_i_size > i_size) {
>>>> + err = f2fs_truncate_blocks(entry->inode,
>>>> + i_size, false);
>>>> + if (err) {
>>>> + f2fs_folio_put(folio, true);
>>>> + break;
>>>> + }
>>>> + f2fs_mark_inode_dirty_sync(entry->inode, true);
>>>> + }
>>>> list_move_tail(&entry->list, tmp_inode_list);
>>>> + }
>>>> next:
>>>> ra_blocks = adjust_por_ra_blocks(sbi, ra_blocks, blkaddr,
>>>> next_blkaddr_of_node(folio));
>>>
>>
>
_______________________________________________
Linux-f2fs-devel mailing list
[email protected]
https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel
