* [f2fs-dev] [PATCH] f2fs: continue to allocate pinned section when gc happens EAGAIN
@ 2025-06-12 3:27 wangzijie
2025-06-12 8:31 ` Chao Yu via Linux-f2fs-devel
0 siblings, 1 reply; 7+ messages in thread
From: wangzijie @ 2025-06-12 3:27 UTC (permalink / raw)
To: jaegeuk, chao; +Cc: wangzijie, linux-kernel, bo.wu, linux-f2fs-devel
Wu Bo once mentioned a fallocate fail scenario in this link[1].
After commit 3fdd89b452c2("f2fs: prevent writing without fallocate()
for pinned files"), we cannot directly generate 4K size file and
pin it, but we can still generate non-segment aligned pinned file:
touch test_file
./f2fs_io pinfile set test_file
./f2fs_io fallocate 0 0 8192 test_file
truncate -s 4096 test_file
By doing this, pin+fallocate failure(gc happens EAGAIN but f2fs shows
enough spare space) may occurs.
From message in commit 2e42b7f817ac("f2fs: stop allocating pinned sections
if EAGAIN happens"), gc EAGAIN doesn't guarantee a free section, so we stop
allocating. But after commit 48ea8b200414 ("f2fs: fix to avoid panic once
fallocation fails for pinfile"), we have a way to avoid panic caused by
concurrent pinfile allocation run out of free section, so I think that we
can continue to allocate pinned section when gc happens EAGAIN. Even if we
don't have free section, f2fs_allocate_pinning_section() can fail with ENOSPC.
[1] https://lore.kernel.org/linux-f2fs-devel/20231030094024.263707-1-bo.wu@vivo.com/t/#u
Signed-off-by: wangzijie <wangzijie1@honor.com>
---
fs/f2fs/file.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
index 6bd3de64f..05c80d2b5 100644
--- a/fs/f2fs/file.c
+++ b/fs/f2fs/file.c
@@ -1859,7 +1859,7 @@ static int f2fs_expand_inode_data(struct inode *inode, loff_t offset,
f2fs_down_write(&sbi->gc_lock);
stat_inc_gc_call_count(sbi, FOREGROUND);
err = f2fs_gc(sbi, &gc_control);
- if (err && err != -ENODATA) {
+ if (err && err != -ENODATA && err != -EAGAIN) {
f2fs_up_write(&sbi->pin_sem);
goto out_err;
}
--
2.25.1
_______________________________________________
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Linux-f2fs-devel@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel
^ permalink raw reply related [flat|nested] 7+ messages in thread
* Re: [f2fs-dev] [PATCH] f2fs: continue to allocate pinned section when gc happens EAGAIN
2025-06-12 3:27 [f2fs-dev] [PATCH] f2fs: continue to allocate pinned section when gc happens EAGAIN wangzijie
@ 2025-06-12 8:31 ` Chao Yu via Linux-f2fs-devel
2025-06-12 12:34 ` wangzijie
0 siblings, 1 reply; 7+ messages in thread
From: Chao Yu via Linux-f2fs-devel @ 2025-06-12 8:31 UTC (permalink / raw)
To: wangzijie, jaegeuk; +Cc: linux-kernel, bo.wu, linux-f2fs-devel
On 6/12/25 11:27, wangzijie wrote:
> Wu Bo once mentioned a fallocate fail scenario in this link[1].
> After commit 3fdd89b452c2("f2fs: prevent writing without fallocate()
> for pinned files"), we cannot directly generate 4K size file and
> pin it, but we can still generate non-segment aligned pinned file:
>
> touch test_file
> ./f2fs_io pinfile set test_file
> ./f2fs_io fallocate 0 0 8192 test_file
> truncate -s 4096 test_file
Well, shouldn't we avoid such case by adding check condition in setattr?
>
> By doing this, pin+fallocate failure(gc happens EAGAIN but f2fs shows
> enough spare space) may occurs.
>
> From message in commit 2e42b7f817ac("f2fs: stop allocating pinned sections
> if EAGAIN happens"), gc EAGAIN doesn't guarantee a free section, so we stop
> allocating. But after commit 48ea8b200414 ("f2fs: fix to avoid panic once
> fallocation fails for pinfile"), we have a way to avoid panic caused by
> concurrent pinfile allocation run out of free section, so I think that we
> can continue to allocate pinned section when gc happens EAGAIN. Even if we
> don't have free section, f2fs_allocate_pinning_section() can fail with ENOSPC.
What do you think of introduce /sys/fs/f2fs/<dev>/reserved_pin_section to
tune @needed parameter of has_not_enough_free_secs()? If we configure it
w/ zero, it can avoid f2fs_gc() before preallocation.
---
fs/f2fs/f2fs.h | 3 +++
fs/f2fs/file.c | 5 ++---
fs/f2fs/super.c | 3 +++
fs/f2fs/sysfs.c | 9 +++++++++
4 files changed, 17 insertions(+), 3 deletions(-)
diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index 785537576aa8..ffb15da570d7 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -1731,6 +1731,9 @@ struct f2fs_sb_info {
/* for skip statistic */
unsigned long long skipped_gc_rwsem; /* FG_GC only */
+ /* free sections reserved for pinned file */
+ unsigned int reserved_pin_section;
+
/* threshold for gc trials on pinned files */
unsigned short gc_pin_file_threshold;
struct f2fs_rwsem pin_sem;
diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
index 696131e655ed..a909f79db178 100644
--- a/fs/f2fs/file.c
+++ b/fs/f2fs/file.c
@@ -1887,9 +1887,8 @@ static int f2fs_expand_inode_data(struct inode *inode, loff_t offset,
}
}
- if (has_not_enough_free_secs(sbi, 0, f2fs_sb_has_blkzoned(sbi) ?
- ZONED_PIN_SEC_REQUIRED_COUNT :
- GET_SEC_FROM_SEG(sbi, overprovision_segments(sbi)))) {
+ if (has_not_enough_free_secs(sbi, 0,
+ sbi->reserved_pin_section)) {
f2fs_down_write(&sbi->gc_lock);
stat_inc_gc_call_count(sbi, FOREGROUND);
err = f2fs_gc(sbi, &gc_control);
diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
index 57adeff5ef25..48b97a95fd63 100644
--- a/fs/f2fs/super.c
+++ b/fs/f2fs/super.c
@@ -4975,6 +4975,9 @@ static int f2fs_fill_super(struct super_block *sb, struct fs_context *fc)
sbi->last_valid_block_count = sbi->total_valid_block_count;
sbi->reserved_blocks = 0;
sbi->current_reserved_blocks = 0;
+ sbi->reserved_pin_section = f2fs_sb_has_blkzoned(sbi) ?
+ ZONED_PIN_SEC_REQUIRED_COUNT :
+ GET_SEC_FROM_SEG(sbi, overprovision_segments(sbi));
limit_reserve_root(sbi);
adjust_unusable_cap_perc(sbi);
diff --git a/fs/f2fs/sysfs.c b/fs/f2fs/sysfs.c
index 75134d69a0bd..51be7ffb38c5 100644
--- a/fs/f2fs/sysfs.c
+++ b/fs/f2fs/sysfs.c
@@ -824,6 +824,13 @@ static ssize_t __sbi_store(struct f2fs_attr *a,
return count;
}
+ if (!strcmp(a->attr.name, "reserved_pin_section")) {
+ if (t > GET_SEC_FROM_SEG(sbi, overprovision_segments(sbi)))
+ return -EINVAL;
+ *ui = (unsigned int)t;
+ return count;
+ }
+
*ui = (unsigned int)t;
return count;
@@ -1130,6 +1137,7 @@ F2FS_SBI_GENERAL_RO_ATTR(unusable_blocks_per_sec);
F2FS_SBI_GENERAL_RW_ATTR(blkzone_alloc_policy);
#endif
F2FS_SBI_GENERAL_RW_ATTR(carve_out);
+F2FS_SBI_GENERAL_RW_ATTR(reserved_pin_section);
/* STAT_INFO ATTR */
#ifdef CONFIG_F2FS_STAT_FS
@@ -1323,6 +1331,7 @@ static struct attribute *f2fs_attrs[] = {
ATTR_LIST(last_age_weight),
ATTR_LIST(max_read_extent_count),
ATTR_LIST(carve_out),
+ ATTR_LIST(reserved_pin_section),
NULL,
};
ATTRIBUTE_GROUPS(f2fs);
--
2.49.0
>
> [1] https://lore.kernel.org/linux-f2fs-devel/20231030094024.263707-1-bo.wu@vivo.com/t/#u
>
> Signed-off-by: wangzijie <wangzijie1@honor.com>
> ---
> fs/f2fs/file.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
> index 6bd3de64f..05c80d2b5 100644
> --- a/fs/f2fs/file.c
> +++ b/fs/f2fs/file.c
> @@ -1859,7 +1859,7 @@ static int f2fs_expand_inode_data(struct inode *inode, loff_t offset,
> f2fs_down_write(&sbi->gc_lock);
> stat_inc_gc_call_count(sbi, FOREGROUND);
> err = f2fs_gc(sbi, &gc_control);
> - if (err && err != -ENODATA) {
> + if (err && err != -ENODATA && err != -EAGAIN) {
> f2fs_up_write(&sbi->pin_sem);
> goto out_err;
> }
_______________________________________________
Linux-f2fs-devel mailing list
Linux-f2fs-devel@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel
^ permalink raw reply related [flat|nested] 7+ messages in thread
* Re: [f2fs-dev] [PATCH] f2fs: continue to allocate pinned section when gc happens EAGAIN
2025-06-12 8:31 ` Chao Yu via Linux-f2fs-devel
@ 2025-06-12 12:34 ` wangzijie
2025-06-12 14:07 ` Chao Yu via Linux-f2fs-devel
2025-06-13 8:25 ` Zhiguo Niu
0 siblings, 2 replies; 7+ messages in thread
From: wangzijie @ 2025-06-12 12:34 UTC (permalink / raw)
To: linux-f2fs-devel; +Cc: feng.han, linux-kernel, bo.wu, jaegeuk, wangzijie1
> On 6/12/25 11:27, wangzijie wrote:
> > Wu Bo once mentioned a fallocate fail scenario in this link[1].
> > After commit 3fdd89b452c2("f2fs: prevent writing without fallocate()
> > for pinned files"), we cannot directly generate 4K size file and
> > pin it, but we can still generate non-segment aligned pinned file:
> >
> > touch test_file
> > ./f2fs_io pinfile set test_file
> > ./f2fs_io fallocate 0 0 8192 test_file
> > truncate -s 4096 test_file
>
> Well, shouldn't we avoid such case by adding check condition in setattr?
Maybe like this?
---
diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
index 6bd3de64f..2f6537d9c 100644
--- a/fs/f2fs/file.c
+++ b/fs/f2fs/file.c
@@ -1027,6 +1027,8 @@ int f2fs_setattr(struct mnt_idmap *idmap, struct dentry *dentry,
struct inode *inode = d_inode(dentry);
struct f2fs_inode_info *fi = F2FS_I(inode);
int err;
+ struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
+ block_t sec_blks = CAP_BLKS_PER_SEC(sbi);
if (unlikely(f2fs_cp_error(F2FS_I_SB(inode))))
return -EIO;
@@ -1047,6 +1049,11 @@ int f2fs_setattr(struct mnt_idmap *idmap, struct dentry *dentry,
!IS_ALIGNED(attr->ia_size,
F2FS_BLK_TO_BYTES(fi->i_cluster_size)))
return -EINVAL;
+ if (f2fs_is_pinned_file(inode) &&
+ attr->ia_size < i_size_read(inode) &&
+ !IS_ALIGNED(attr->ia_size,
+ F2FS_BLK_TO_BYTES(sec_blks)));
+ return -EINVAL;
}
err = setattr_prepare(idmap, dentry, attr);
---
> >
> > By doing this, pin+fallocate failure(gc happens EAGAIN but f2fs shows
> > enough spare space) may occurs.
> >
> > From message in commit 2e42b7f817ac("f2fs: stop allocating pinned sections
> > if EAGAIN happens"), gc EAGAIN doesn't guarantee a free section, so we stop
> > allocating. But after commit 48ea8b200414 ("f2fs: fix to avoid panic once
> > fallocation fails for pinfile"), we have a way to avoid panic caused by
> > concurrent pinfile allocation run out of free section, so I think that we
> > can continue to allocate pinned section when gc happens EAGAIN. Even if we
> > don't have free section, f2fs_allocate_pinning_section() can fail with ENOSPC.
>
> What do you think of introduce /sys/fs/f2fs/<dev>/reserved_pin_section to
> tune @needed parameter of has_not_enough_free_secs()? If we configure it
> w/ zero, it can avoid f2fs_gc() before preallocation.
>
> ---
> fs/f2fs/f2fs.h | 3 +++
> fs/f2fs/file.c | 5 ++---
> fs/f2fs/super.c | 3 +++
> fs/f2fs/sysfs.c | 9 +++++++++
> 4 files changed, 17 insertions(+), 3 deletions(-)
>
> diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
> index 785537576aa8..ffb15da570d7 100644
> --- a/fs/f2fs/f2fs.h
> +++ b/fs/f2fs/f2fs.h
> @@ -1731,6 +1731,9 @@ struct f2fs_sb_info {
> /* for skip statistic */
> unsigned long long skipped_gc_rwsem; /* FG_GC only */
>
> + /* free sections reserved for pinned file */
> + unsigned int reserved_pin_section;
> +
> /* threshold for gc trials on pinned files */
> unsigned short gc_pin_file_threshold;
> struct f2fs_rwsem pin_sem;
> diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
> index 696131e655ed..a909f79db178 100644
> --- a/fs/f2fs/file.c
> +++ b/fs/f2fs/file.c
> @@ -1887,9 +1887,8 @@ static int f2fs_expand_inode_data(struct inode *inode, loff_t offset,
> }
> }
>
> - if (has_not_enough_free_secs(sbi, 0, f2fs_sb_has_blkzoned(sbi) ?
> - ZONED_PIN_SEC_REQUIRED_COUNT :
> - GET_SEC_FROM_SEG(sbi, overprovision_segments(sbi)))) {
> + if (has_not_enough_free_secs(sbi, 0,
> + sbi->reserved_pin_section)) {
> f2fs_down_write(&sbi->gc_lock);
> stat_inc_gc_call_count(sbi, FOREGROUND);
> err = f2fs_gc(sbi, &gc_control);
> diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
> index 57adeff5ef25..48b97a95fd63 100644
> --- a/fs/f2fs/super.c
> +++ b/fs/f2fs/super.c
> @@ -4975,6 +4975,9 @@ static int f2fs_fill_super(struct super_block *sb, struct fs_context *fc)
> sbi->last_valid_block_count = sbi->total_valid_block_count;
> sbi->reserved_blocks = 0;
> sbi->current_reserved_blocks = 0;
> + sbi->reserved_pin_section = f2fs_sb_has_blkzoned(sbi) ?
> + ZONED_PIN_SEC_REQUIRED_COUNT :
> + GET_SEC_FROM_SEG(sbi, overprovision_segments(sbi));
> limit_reserve_root(sbi);
> adjust_unusable_cap_perc(sbi);
>
> diff --git a/fs/f2fs/sysfs.c b/fs/f2fs/sysfs.c
> index 75134d69a0bd..51be7ffb38c5 100644
> --- a/fs/f2fs/sysfs.c
> +++ b/fs/f2fs/sysfs.c
> @@ -824,6 +824,13 @@ static ssize_t __sbi_store(struct f2fs_attr *a,
> return count;
> }
>
> + if (!strcmp(a->attr.name, "reserved_pin_section")) {
> + if (t > GET_SEC_FROM_SEG(sbi, overprovision_segments(sbi)))
> + return -EINVAL;
> + *ui = (unsigned int)t;
> + return count;
> + }
> +
> *ui = (unsigned int)t;
>
> return count;
> @@ -1130,6 +1137,7 @@ F2FS_SBI_GENERAL_RO_ATTR(unusable_blocks_per_sec);
> F2FS_SBI_GENERAL_RW_ATTR(blkzone_alloc_policy);
> #endif
> F2FS_SBI_GENERAL_RW_ATTR(carve_out);
> +F2FS_SBI_GENERAL_RW_ATTR(reserved_pin_section);
>
> /* STAT_INFO ATTR */
> #ifdef CONFIG_F2FS_STAT_FS
> @@ -1323,6 +1331,7 @@ static struct attribute *f2fs_attrs[] = {
> ATTR_LIST(last_age_weight),
> ATTR_LIST(max_read_extent_count),
> ATTR_LIST(carve_out),
> + ATTR_LIST(reserved_pin_section),
> NULL,
> };
> ATTRIBUTE_GROUPS(f2fs);
> --
> 2.49.0
I think it's a good way to solve this problem. Thank you!
> >
> > [1] https://lore.kernel.org/linux-f2fs-devel/20231030094024.263707-1-bo.wu@vivo.com/t/#u
> >
> > Signed-off-by: wangzijie <wangzijie1@honor.com>
> > ---
> > fs/f2fs/file.c | 2 +-
> > 1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
> > index 6bd3de64f..05c80d2b5 100644
> > --- a/fs/f2fs/file.c
> > +++ b/fs/f2fs/file.c
> > @@ -1859,7 +1859,7 @@ static int f2fs_expand_inode_data(struct inode *inode, loff_t offset,
> > f2fs_down_write(&sbi->gc_lock);
> > stat_inc_gc_call_count(sbi, FOREGROUND);
> > err = f2fs_gc(sbi, &gc_control);
> > - if (err && err != -ENODATA) {
> > + if (err && err != -ENODATA && err != -EAGAIN) {
> > f2fs_up_write(&sbi->pin_sem);
> > goto out_err;
> > }
>
>
>
> _______________________________________________
> Linux-f2fs-devel mailing list
> Linux-f2fs-devel@lists.sourceforge.net
> https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel
_______________________________________________
Linux-f2fs-devel mailing list
Linux-f2fs-devel@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel
^ permalink raw reply related [flat|nested] 7+ messages in thread
* Re: [f2fs-dev] [PATCH] f2fs: continue to allocate pinned section when gc happens EAGAIN
2025-06-12 12:34 ` wangzijie
@ 2025-06-12 14:07 ` Chao Yu via Linux-f2fs-devel
2025-06-13 2:03 ` wangzijie
2025-06-13 8:25 ` Zhiguo Niu
1 sibling, 1 reply; 7+ messages in thread
From: Chao Yu via Linux-f2fs-devel @ 2025-06-12 14:07 UTC (permalink / raw)
To: wangzijie, linux-f2fs-devel; +Cc: feng.han, linux-kernel, bo.wu, jaegeuk
On 2025/6/12 20:34, wangzijie wrote:
>> On 6/12/25 11:27, wangzijie wrote:
>>> Wu Bo once mentioned a fallocate fail scenario in this link[1].
>>> After commit 3fdd89b452c2("f2fs: prevent writing without fallocate()
>>> for pinned files"), we cannot directly generate 4K size file and
>>> pin it, but we can still generate non-segment aligned pinned file:
>>>
>>> touch test_file
>>> ./f2fs_io pinfile set test_file
>>> ./f2fs_io fallocate 0 0 8192 test_file
>>> truncate -s 4096 test_file
>>
>> Well, shouldn't we avoid such case by adding check condition in setattr?
>
> Maybe like this?
>
> ---
> diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
> index 6bd3de64f..2f6537d9c 100644
> --- a/fs/f2fs/file.c
> +++ b/fs/f2fs/file.c
> @@ -1027,6 +1027,8 @@ int f2fs_setattr(struct mnt_idmap *idmap, struct dentry *dentry,
> struct inode *inode = d_inode(dentry);
> struct f2fs_inode_info *fi = F2FS_I(inode);
> int err;
> + struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
> + block_t sec_blks = CAP_BLKS_PER_SEC(sbi);
>
> if (unlikely(f2fs_cp_error(F2FS_I_SB(inode))))
> return -EIO;
> @@ -1047,6 +1049,11 @@ int f2fs_setattr(struct mnt_idmap *idmap, struct dentry *dentry,
> !IS_ALIGNED(attr->ia_size,
> F2FS_BLK_TO_BYTES(fi->i_cluster_size)))
> return -EINVAL;
> + if (f2fs_is_pinned_file(inode) &&
> + attr->ia_size < i_size_read(inode) &&
> + !IS_ALIGNED(attr->ia_size,
> + F2FS_BLK_TO_BYTES(sec_blks)));
> + return -EINVAL;
> }
I think so, can you please send a formal patch?
>
> err = setattr_prepare(idmap, dentry, attr);
> ---
>
>>>
>>> By doing this, pin+fallocate failure(gc happens EAGAIN but f2fs shows
>>> enough spare space) may occurs.
>>>
>>> From message in commit 2e42b7f817ac("f2fs: stop allocating pinned sections
>>> if EAGAIN happens"), gc EAGAIN doesn't guarantee a free section, so we stop
>>> allocating. But after commit 48ea8b200414 ("f2fs: fix to avoid panic once
>>> fallocation fails for pinfile"), we have a way to avoid panic caused by
>>> concurrent pinfile allocation run out of free section, so I think that we
>>> can continue to allocate pinned section when gc happens EAGAIN. Even if we
>>> don't have free section, f2fs_allocate_pinning_section() can fail with ENOSPC.
>>
>> What do you think of introduce /sys/fs/f2fs/<dev>/reserved_pin_section to
>> tune @needed parameter of has_not_enough_free_secs()? If we configure it
>> w/ zero, it can avoid f2fs_gc() before preallocation.
>>
>> ---
>> fs/f2fs/f2fs.h | 3 +++
>> fs/f2fs/file.c | 5 ++---
>> fs/f2fs/super.c | 3 +++
>> fs/f2fs/sysfs.c | 9 +++++++++
>> 4 files changed, 17 insertions(+), 3 deletions(-)
>>
>> diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
>> index 785537576aa8..ffb15da570d7 100644
>> --- a/fs/f2fs/f2fs.h
>> +++ b/fs/f2fs/f2fs.h
>> @@ -1731,6 +1731,9 @@ struct f2fs_sb_info {
>> /* for skip statistic */
>> unsigned long long skipped_gc_rwsem; /* FG_GC only */
>>
>> + /* free sections reserved for pinned file */
>> + unsigned int reserved_pin_section;
>> +
>> /* threshold for gc trials on pinned files */
>> unsigned short gc_pin_file_threshold;
>> struct f2fs_rwsem pin_sem;
>> diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
>> index 696131e655ed..a909f79db178 100644
>> --- a/fs/f2fs/file.c
>> +++ b/fs/f2fs/file.c
>> @@ -1887,9 +1887,8 @@ static int f2fs_expand_inode_data(struct inode *inode, loff_t offset,
>> }
>> }
>>
>> - if (has_not_enough_free_secs(sbi, 0, f2fs_sb_has_blkzoned(sbi) ?
>> - ZONED_PIN_SEC_REQUIRED_COUNT :
>> - GET_SEC_FROM_SEG(sbi, overprovision_segments(sbi)))) {
>> + if (has_not_enough_free_secs(sbi, 0,
>> + sbi->reserved_pin_section)) {
>> f2fs_down_write(&sbi->gc_lock);
>> stat_inc_gc_call_count(sbi, FOREGROUND);
>> err = f2fs_gc(sbi, &gc_control);
>> diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
>> index 57adeff5ef25..48b97a95fd63 100644
>> --- a/fs/f2fs/super.c
>> +++ b/fs/f2fs/super.c
>> @@ -4975,6 +4975,9 @@ static int f2fs_fill_super(struct super_block *sb, struct fs_context *fc)
>> sbi->last_valid_block_count = sbi->total_valid_block_count;
>> sbi->reserved_blocks = 0;
>> sbi->current_reserved_blocks = 0;
>> + sbi->reserved_pin_section = f2fs_sb_has_blkzoned(sbi) ?
>> + ZONED_PIN_SEC_REQUIRED_COUNT :
>> + GET_SEC_FROM_SEG(sbi, overprovision_segments(sbi));
>> limit_reserve_root(sbi);
>> adjust_unusable_cap_perc(sbi);
>>
>> diff --git a/fs/f2fs/sysfs.c b/fs/f2fs/sysfs.c
>> index 75134d69a0bd..51be7ffb38c5 100644
>> --- a/fs/f2fs/sysfs.c
>> +++ b/fs/f2fs/sysfs.c
>> @@ -824,6 +824,13 @@ static ssize_t __sbi_store(struct f2fs_attr *a,
>> return count;
>> }
>>
>> + if (!strcmp(a->attr.name, "reserved_pin_section")) {
>> + if (t > GET_SEC_FROM_SEG(sbi, overprovision_segments(sbi)))
>> + return -EINVAL;
>> + *ui = (unsigned int)t;
>> + return count;
>> + }
>> +
>> *ui = (unsigned int)t;
>>
>> return count;
>> @@ -1130,6 +1137,7 @@ F2FS_SBI_GENERAL_RO_ATTR(unusable_blocks_per_sec);
>> F2FS_SBI_GENERAL_RW_ATTR(blkzone_alloc_policy);
>> #endif
>> F2FS_SBI_GENERAL_RW_ATTR(carve_out);
>> +F2FS_SBI_GENERAL_RW_ATTR(reserved_pin_section);
>>
>> /* STAT_INFO ATTR */
>> #ifdef CONFIG_F2FS_STAT_FS
>> @@ -1323,6 +1331,7 @@ static struct attribute *f2fs_attrs[] = {
>> ATTR_LIST(last_age_weight),
>> ATTR_LIST(max_read_extent_count),
>> ATTR_LIST(carve_out),
>> + ATTR_LIST(reserved_pin_section),
>> NULL,
>> };
>> ATTRIBUTE_GROUPS(f2fs);
>> --
>> 2.49.0
>
> I think it's a good way to solve this problem. Thank you!
Sent a formal patch w/ below link. :)
https://lore.kernel.org/linux-f2fs-devel/20250612140526.6435-1-chao@kernel.org
Thanks,
>
>
>>>
>>> [1] https://lore.kernel.org/linux-f2fs-devel/20231030094024.263707-1-bo.wu@vivo.com/t/#u
>>>
>>> Signed-off-by: wangzijie <wangzijie1@honor.com>
>>> ---
>>> fs/f2fs/file.c | 2 +-
>>> 1 file changed, 1 insertion(+), 1 deletion(-)
>>>
>>> diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
>>> index 6bd3de64f..05c80d2b5 100644
>>> --- a/fs/f2fs/file.c
>>> +++ b/fs/f2fs/file.c
>>> @@ -1859,7 +1859,7 @@ static int f2fs_expand_inode_data(struct inode *inode, loff_t offset,
>>> f2fs_down_write(&sbi->gc_lock);
>>> stat_inc_gc_call_count(sbi, FOREGROUND);
>>> err = f2fs_gc(sbi, &gc_control);
>>> - if (err && err != -ENODATA) {
>>> + if (err && err != -ENODATA && err != -EAGAIN) {
>>> f2fs_up_write(&sbi->pin_sem);
>>> goto out_err;
>>> }
>>
>>
>>
>> _______________________________________________
>> Linux-f2fs-devel mailing list
>> Linux-f2fs-devel@lists.sourceforge.net
>> https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel
>
_______________________________________________
Linux-f2fs-devel mailing list
Linux-f2fs-devel@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [f2fs-dev] [PATCH] f2fs: continue to allocate pinned section when gc happens EAGAIN
2025-06-12 14:07 ` Chao Yu via Linux-f2fs-devel
@ 2025-06-13 2:03 ` wangzijie
0 siblings, 0 replies; 7+ messages in thread
From: wangzijie @ 2025-06-13 2:03 UTC (permalink / raw)
To: linux-f2fs-devel; +Cc: feng.han, linux-kernel, bo.wu, jaegeuk, wangzijie1
>On 2025/6/12 20:34, wangzijie wrote:
>>> On 6/12/25 11:27, wangzijie wrote:
>>>> Wu Bo once mentioned a fallocate fail scenario in this link[1].
>>>> After commit 3fdd89b452c2("f2fs: prevent writing without fallocate()
>>>> for pinned files"), we cannot directly generate 4K size file and
>>>> pin it, but we can still generate non-segment aligned pinned file:
>>>>
>>>> touch test_file
>>>> ./f2fs_io pinfile set test_file
>>>> ./f2fs_io fallocate 0 0 8192 test_file
>>>> truncate -s 4096 test_file
>>>
>>> Well, shouldn't we avoid such case by adding check condition in setattr?
>>
>> Maybe like this?
>>
>> ---
>> diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
>> index 6bd3de64f..2f6537d9c 100644
>> --- a/fs/f2fs/file.c
>> +++ b/fs/f2fs/file.c
>> @@ -1027,6 +1027,8 @@ int f2fs_setattr(struct mnt_idmap *idmap, struct dentry *dentry,
>> struct inode *inode = d_inode(dentry);
>> struct f2fs_inode_info *fi = F2FS_I(inode);
>> int err;
>> + struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
>> + block_t sec_blks = CAP_BLKS_PER_SEC(sbi);
>>
>> if (unlikely(f2fs_cp_error(F2FS_I_SB(inode))))
>> return -EIO;
>> @@ -1047,6 +1049,11 @@ int f2fs_setattr(struct mnt_idmap *idmap, struct dentry *dentry,
>> !IS_ALIGNED(attr->ia_size,
>> F2FS_BLK_TO_BYTES(fi->i_cluster_size)))
>> return -EINVAL;
>> + if (f2fs_is_pinned_file(inode) &&
>> + attr->ia_size < i_size_read(inode) &&
>> + !IS_ALIGNED(attr->ia_size,
>> + F2FS_BLK_TO_BYTES(sec_blks)));
>> + return -EINVAL;
>> }
>
>I think so, can you please send a formal patch?
OK, I will send a formal patch later.
>>
>> err = setattr_prepare(idmap, dentry, attr);
>> ---
>>
>>>>
>>>> By doing this, pin+fallocate failure(gc happens EAGAIN but f2fs shows
>>>> enough spare space) may occurs.
>>>>
>>>> From message in commit 2e42b7f817ac("f2fs: stop allocating pinned sections
>>>> if EAGAIN happens"), gc EAGAIN doesn't guarantee a free section, so we stop
>>>> allocating. But after commit 48ea8b200414 ("f2fs: fix to avoid panic once
>>>> fallocation fails for pinfile"), we have a way to avoid panic caused by
>>>> concurrent pinfile allocation run out of free section, so I think that we
>>>> can continue to allocate pinned section when gc happens EAGAIN. Even if we
>>>> don't have free section, f2fs_allocate_pinning_section() can fail with ENOSPC.
>>>
>>> What do you think of introduce /sys/fs/f2fs/<dev>/reserved_pin_section to
>>> tune @needed parameter of has_not_enough_free_secs()? If we configure it
>>> w/ zero, it can avoid f2fs_gc() before preallocation.
>>>
>>> ---
>>> fs/f2fs/f2fs.h | 3 +++
>>> fs/f2fs/file.c | 5 ++---
>>> fs/f2fs/super.c | 3 +++
>>> fs/f2fs/sysfs.c | 9 +++++++++
>>> 4 files changed, 17 insertions(+), 3 deletions(-)
>>>
>>> diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
>>> index 785537576aa8..ffb15da570d7 100644
>>> --- a/fs/f2fs/f2fs.h
>>> +++ b/fs/f2fs/f2fs.h
>>> @@ -1731,6 +1731,9 @@ struct f2fs_sb_info {
>>> /* for skip statistic */
>>> unsigned long long skipped_gc_rwsem; /* FG_GC only */
>>>
>>> + /* free sections reserved for pinned file */
>>> + unsigned int reserved_pin_section;
>>> +
>>> /* threshold for gc trials on pinned files */
>>> unsigned short gc_pin_file_threshold;
>>> struct f2fs_rwsem pin_sem;
>>> diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
>>> index 696131e655ed..a909f79db178 100644
>>> --- a/fs/f2fs/file.c
>>> +++ b/fs/f2fs/file.c
>>> @@ -1887,9 +1887,8 @@ static int f2fs_expand_inode_data(struct inode *inode, loff_t offset,
>>> }
>>> }
>>>
>>> - if (has_not_enough_free_secs(sbi, 0, f2fs_sb_has_blkzoned(sbi) ?
>>> - ZONED_PIN_SEC_REQUIRED_COUNT :
>>> - GET_SEC_FROM_SEG(sbi, overprovision_segments(sbi)))) {
>>> + if (has_not_enough_free_secs(sbi, 0,
>>> + sbi->reserved_pin_section)) {
>>> f2fs_down_write(&sbi->gc_lock);
>>> stat_inc_gc_call_count(sbi, FOREGROUND);
>>> err = f2fs_gc(sbi, &gc_control);
>>> diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
>>> index 57adeff5ef25..48b97a95fd63 100644
>>> --- a/fs/f2fs/super.c
>>> +++ b/fs/f2fs/super.c
>>> @@ -4975,6 +4975,9 @@ static int f2fs_fill_super(struct super_block *sb, struct fs_context *fc)
>>> sbi->last_valid_block_count = sbi->total_valid_block_count;
>>> sbi->reserved_blocks = 0;
>>> sbi->current_reserved_blocks = 0;
>>> + sbi->reserved_pin_section = f2fs_sb_has_blkzoned(sbi) ?
>>> + ZONED_PIN_SEC_REQUIRED_COUNT :
>>> + GET_SEC_FROM_SEG(sbi, overprovision_segments(sbi));
>>> limit_reserve_root(sbi);
>>> adjust_unusable_cap_perc(sbi);
>>>
>>> diff --git a/fs/f2fs/sysfs.c b/fs/f2fs/sysfs.c
>>> index 75134d69a0bd..51be7ffb38c5 100644
>>> --- a/fs/f2fs/sysfs.c
>>> +++ b/fs/f2fs/sysfs.c
>>> @@ -824,6 +824,13 @@ static ssize_t __sbi_store(struct f2fs_attr *a,
>>> return count;
>>> }
>>>
>>> + if (!strcmp(a->attr.name, "reserved_pin_section")) {
>>> + if (t > GET_SEC_FROM_SEG(sbi, overprovision_segments(sbi)))
>>> + return -EINVAL;
>>> + *ui = (unsigned int)t;
>>> + return count;
>>> + }
>>> +
>>> *ui = (unsigned int)t;
>>>
>>> return count;
>>> @@ -1130,6 +1137,7 @@ F2FS_SBI_GENERAL_RO_ATTR(unusable_blocks_per_sec);
>>> F2FS_SBI_GENERAL_RW_ATTR(blkzone_alloc_policy);
>>> #endif
>>> F2FS_SBI_GENERAL_RW_ATTR(carve_out);
>>> +F2FS_SBI_GENERAL_RW_ATTR(reserved_pin_section);
>>>
>>> /* STAT_INFO ATTR */
>>> #ifdef CONFIG_F2FS_STAT_FS
>>> @@ -1323,6 +1331,7 @@ static struct attribute *f2fs_attrs[] = {
>>> ATTR_LIST(last_age_weight),
>>> ATTR_LIST(max_read_extent_count),
>>> ATTR_LIST(carve_out),
>>> + ATTR_LIST(reserved_pin_section),
>>> NULL,
>>> };
>>> ATTRIBUTE_GROUPS(f2fs);
>>> --
>>> 2.49.0
>>
>> I think it's a good way to solve this problem. Thank you!
>
>Sent a formal patch w/ below link. :)
>
>https://lore.kernel.org/linux-f2fs-devel/20250612140526.6435-1-chao@kernel.org
>
>Thanks,
Thanks, I'll take a look at it.
>>
>>
>>>>
>>>> [1] https://lore.kernel.org/linux-f2fs-devel/20231030094024.263707-1-bo.wu@vivo.com/t/#u
>>>>
>>>> Signed-off-by: wangzijie <wangzijie1@honor.com>
>>>> ---
>>>> fs/f2fs/file.c | 2 +-
>>>> 1 file changed, 1 insertion(+), 1 deletion(-)
>>>>
>>>> diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
>>>> index 6bd3de64f..05c80d2b5 100644
>>>> --- a/fs/f2fs/file.c
>>>> +++ b/fs/f2fs/file.c
>>>> @@ -1859,7 +1859,7 @@ static int f2fs_expand_inode_data(struct inode *inode, loff_t offset,
>>>> f2fs_down_write(&sbi->gc_lock);
>>>> stat_inc_gc_call_count(sbi, FOREGROUND);
>>>> err = f2fs_gc(sbi, &gc_control);
>>>> - if (err && err != -ENODATA) {
>>>> + if (err && err != -ENODATA && err != -EAGAIN) {
>>>> f2fs_up_write(&sbi->pin_sem);
>>>> goto out_err;
>>>> }
>>>
>>>
>>>
>>> _______________________________________________
>>> Linux-f2fs-devel mailing list
>>> Linux-f2fs-devel@lists.sourceforge.net
>>> https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel
>>
>
>
>
>_______________________________________________
>Linux-f2fs-devel mailing list
>Linux-f2fs-devel@lists.sourceforge.net
>https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel
_______________________________________________
Linux-f2fs-devel mailing list
Linux-f2fs-devel@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [f2fs-dev] [PATCH] f2fs: continue to allocate pinned section when gc happens EAGAIN
2025-06-12 12:34 ` wangzijie
2025-06-12 14:07 ` Chao Yu via Linux-f2fs-devel
@ 2025-06-13 8:25 ` Zhiguo Niu
2025-06-13 8:49 ` Chao Yu via Linux-f2fs-devel
1 sibling, 1 reply; 7+ messages in thread
From: Zhiguo Niu @ 2025-06-13 8:25 UTC (permalink / raw)
To: wangzijie; +Cc: jaegeuk, bo.wu, linux-kernel, feng.han, linux-f2fs-devel
wangzijie <wangzijie1@honor.com> 于2025年6月12日周四 20:38写道：
>
> > On 6/12/25 11:27, wangzijie wrote:
> > > Wu Bo once mentioned a fallocate fail scenario in this link[1].
> > > After commit 3fdd89b452c2("f2fs: prevent writing without fallocate()
> > > for pinned files"), we cannot directly generate 4K size file and
> > > pin it, but we can still generate non-segment aligned pinned file:
> > >
> > > touch test_file
> > > ./f2fs_io pinfile set test_file
> > > ./f2fs_io fallocate 0 0 8192 test_file
> > > truncate -s 4096 test_file
> >
> > Well, shouldn't we avoid such case by adding check condition in setattr?
>
> Maybe like this?
>
> ---
> diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
> index 6bd3de64f..2f6537d9c 100644
> --- a/fs/f2fs/file.c
> +++ b/fs/f2fs/file.c
> @@ -1027,6 +1027,8 @@ int f2fs_setattr(struct mnt_idmap *idmap, struct dentry *dentry,
> struct inode *inode = d_inode(dentry);
> struct f2fs_inode_info *fi = F2FS_I(inode);
> int err;
> + struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
> + block_t sec_blks = CAP_BLKS_PER_SEC(sbi);
>
> if (unlikely(f2fs_cp_error(F2FS_I_SB(inode))))
> return -EIO;
> @@ -1047,6 +1049,11 @@ int f2fs_setattr(struct mnt_idmap *idmap, struct dentry *dentry,
> !IS_ALIGNED(attr->ia_size,
> F2FS_BLK_TO_BYTES(fi->i_cluster_size)))
> return -EINVAL;
> + if (f2fs_is_pinned_file(inode) &&
> + attr->ia_size < i_size_read(inode) &&
> + !IS_ALIGNED(attr->ia_size,
> + F2FS_BLK_TO_BYTES(sec_blks)));
> + return -EINVAL;
Hi Chao and zijie,
Excuse me ,I'm a bit confused about this:
when a pin file size is not alinged with size of "section", it can not
be truncated?
thanks！
> }
>
> err = setattr_prepare(idmap, dentry, attr);
> ---
>
> > >
> > > By doing this, pin+fallocate failure(gc happens EAGAIN but f2fs shows
> > > enough spare space) may occurs.
> > >
> > > From message in commit 2e42b7f817ac("f2fs: stop allocating pinned sections
> > > if EAGAIN happens"), gc EAGAIN doesn't guarantee a free section, so we stop
> > > allocating. But after commit 48ea8b200414 ("f2fs: fix to avoid panic once
> > > fallocation fails for pinfile"), we have a way to avoid panic caused by
> > > concurrent pinfile allocation run out of free section, so I think that we
> > > can continue to allocate pinned section when gc happens EAGAIN. Even if we
> > > don't have free section, f2fs_allocate_pinning_section() can fail with ENOSPC.
> >
> > What do you think of introduce /sys/fs/f2fs/<dev>/reserved_pin_section to
> > tune @needed parameter of has_not_enough_free_secs()? If we configure it
> > w/ zero, it can avoid f2fs_gc() before preallocation.
> >
> > ---
> > fs/f2fs/f2fs.h | 3 +++
> > fs/f2fs/file.c | 5 ++---
> > fs/f2fs/super.c | 3 +++
> > fs/f2fs/sysfs.c | 9 +++++++++
> > 4 files changed, 17 insertions(+), 3 deletions(-)
> >
> > diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
> > index 785537576aa8..ffb15da570d7 100644
> > --- a/fs/f2fs/f2fs.h
> > +++ b/fs/f2fs/f2fs.h
> > @@ -1731,6 +1731,9 @@ struct f2fs_sb_info {
> > /* for skip statistic */
> > unsigned long long skipped_gc_rwsem; /* FG_GC only */
> >
> > + /* free sections reserved for pinned file */
> > + unsigned int reserved_pin_section;
> > +
> > /* threshold for gc trials on pinned files */
> > unsigned short gc_pin_file_threshold;
> > struct f2fs_rwsem pin_sem;
> > diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
> > index 696131e655ed..a909f79db178 100644
> > --- a/fs/f2fs/file.c
> > +++ b/fs/f2fs/file.c
> > @@ -1887,9 +1887,8 @@ static int f2fs_expand_inode_data(struct inode *inode, loff_t offset,
> > }
> > }
> >
> > - if (has_not_enough_free_secs(sbi, 0, f2fs_sb_has_blkzoned(sbi) ?
> > - ZONED_PIN_SEC_REQUIRED_COUNT :
> > - GET_SEC_FROM_SEG(sbi, overprovision_segments(sbi)))) {
> > + if (has_not_enough_free_secs(sbi, 0,
> > + sbi->reserved_pin_section)) {
> > f2fs_down_write(&sbi->gc_lock);
> > stat_inc_gc_call_count(sbi, FOREGROUND);
> > err = f2fs_gc(sbi, &gc_control);
> > diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
> > index 57adeff5ef25..48b97a95fd63 100644
> > --- a/fs/f2fs/super.c
> > +++ b/fs/f2fs/super.c
> > @@ -4975,6 +4975,9 @@ static int f2fs_fill_super(struct super_block *sb, struct fs_context *fc)
> > sbi->last_valid_block_count = sbi->total_valid_block_count;
> > sbi->reserved_blocks = 0;
> > sbi->current_reserved_blocks = 0;
> > + sbi->reserved_pin_section = f2fs_sb_has_blkzoned(sbi) ?
> > + ZONED_PIN_SEC_REQUIRED_COUNT :
> > + GET_SEC_FROM_SEG(sbi, overprovision_segments(sbi));
> > limit_reserve_root(sbi);
> > adjust_unusable_cap_perc(sbi);
> >
> > diff --git a/fs/f2fs/sysfs.c b/fs/f2fs/sysfs.c
> > index 75134d69a0bd..51be7ffb38c5 100644
> > --- a/fs/f2fs/sysfs.c
> > +++ b/fs/f2fs/sysfs.c
> > @@ -824,6 +824,13 @@ static ssize_t __sbi_store(struct f2fs_attr *a,
> > return count;
> > }
> >
> > + if (!strcmp(a->attr.name, "reserved_pin_section")) {
> > + if (t > GET_SEC_FROM_SEG(sbi, overprovision_segments(sbi)))
> > + return -EINVAL;
> > + *ui = (unsigned int)t;
> > + return count;
> > + }
> > +
> > *ui = (unsigned int)t;
> >
> > return count;
> > @@ -1130,6 +1137,7 @@ F2FS_SBI_GENERAL_RO_ATTR(unusable_blocks_per_sec);
> > F2FS_SBI_GENERAL_RW_ATTR(blkzone_alloc_policy);
> > #endif
> > F2FS_SBI_GENERAL_RW_ATTR(carve_out);
> > +F2FS_SBI_GENERAL_RW_ATTR(reserved_pin_section);
> >
> > /* STAT_INFO ATTR */
> > #ifdef CONFIG_F2FS_STAT_FS
> > @@ -1323,6 +1331,7 @@ static struct attribute *f2fs_attrs[] = {
> > ATTR_LIST(last_age_weight),
> > ATTR_LIST(max_read_extent_count),
> > ATTR_LIST(carve_out),
> > + ATTR_LIST(reserved_pin_section),
> > NULL,
> > };
> > ATTRIBUTE_GROUPS(f2fs);
> > --
> > 2.49.0
>
> I think it's a good way to solve this problem. Thank you!
>
>
> > >
> > > [1] https://lore.kernel.org/linux-f2fs-devel/20231030094024.263707-1-bo.wu@vivo.com/t/#u
> > >
> > > Signed-off-by: wangzijie <wangzijie1@honor.com>
> > > ---
> > > fs/f2fs/file.c | 2 +-
> > > 1 file changed, 1 insertion(+), 1 deletion(-)
> > >
> > > diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
> > > index 6bd3de64f..05c80d2b5 100644
> > > --- a/fs/f2fs/file.c
> > > +++ b/fs/f2fs/file.c
> > > @@ -1859,7 +1859,7 @@ static int f2fs_expand_inode_data(struct inode *inode, loff_t offset,
> > > f2fs_down_write(&sbi->gc_lock);
> > > stat_inc_gc_call_count(sbi, FOREGROUND);
> > > err = f2fs_gc(sbi, &gc_control);
> > > - if (err && err != -ENODATA) {
> > > + if (err && err != -ENODATA && err != -EAGAIN) {
> > > f2fs_up_write(&sbi->pin_sem);
> > > goto out_err;
> > > }
> >
> >
> >
> > _______________________________________________
> > Linux-f2fs-devel mailing list
> > Linux-f2fs-devel@lists.sourceforge.net
> > https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel
>
>
>
> _______________________________________________
> Linux-f2fs-devel mailing list
> Linux-f2fs-devel@lists.sourceforge.net
> https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel
_______________________________________________
Linux-f2fs-devel mailing list
Linux-f2fs-devel@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [f2fs-dev] [PATCH] f2fs: continue to allocate pinned section when gc happens EAGAIN
2025-06-13 8:25 ` Zhiguo Niu
@ 2025-06-13 8:49 ` Chao Yu via Linux-f2fs-devel
0 siblings, 0 replies; 7+ messages in thread
From: Chao Yu via Linux-f2fs-devel @ 2025-06-13 8:49 UTC (permalink / raw)
To: Zhiguo Niu, wangzijie
Cc: feng.han, linux-kernel, linux-f2fs-devel, bo.wu, jaegeuk
On 2025/6/13 16:25, Zhiguo Niu wrote:
> wangzijie <wangzijie1@honor.com> 于2025年6月12日周四 20:38写道：
>>
>>> On 6/12/25 11:27, wangzijie wrote:
>>>> Wu Bo once mentioned a fallocate fail scenario in this link[1].
>>>> After commit 3fdd89b452c2("f2fs: prevent writing without fallocate()
>>>> for pinned files"), we cannot directly generate 4K size file and
>>>> pin it, but we can still generate non-segment aligned pinned file:
>>>>
>>>> touch test_file
>>>> ./f2fs_io pinfile set test_file
>>>> ./f2fs_io fallocate 0 0 8192 test_file
>>>> truncate -s 4096 test_file
>>>
>>> Well, shouldn't we avoid such case by adding check condition in setattr?
>>
>> Maybe like this?
>>
>> ---
>> diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
>> index 6bd3de64f..2f6537d9c 100644
>> --- a/fs/f2fs/file.c
>> +++ b/fs/f2fs/file.c
>> @@ -1027,6 +1027,8 @@ int f2fs_setattr(struct mnt_idmap *idmap, struct dentry *dentry,
>> struct inode *inode = d_inode(dentry);
>> struct f2fs_inode_info *fi = F2FS_I(inode);
>> int err;
>> + struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
>> + block_t sec_blks = CAP_BLKS_PER_SEC(sbi);
>>
>> if (unlikely(f2fs_cp_error(F2FS_I_SB(inode))))
>> return -EIO;
>> @@ -1047,6 +1049,11 @@ int f2fs_setattr(struct mnt_idmap *idmap, struct dentry *dentry,
>> !IS_ALIGNED(attr->ia_size,
>> F2FS_BLK_TO_BYTES(fi->i_cluster_size)))
>> return -EINVAL;
>> + if (f2fs_is_pinned_file(inode) &&
>> + attr->ia_size < i_size_read(inode) &&
>> + !IS_ALIGNED(attr->ia_size,
>> + F2FS_BLK_TO_BYTES(sec_blks)));
>> + return -EINVAL;
> Hi Chao and zijie,
> Excuse me ,I'm a bit confused about this:
> when a pin file size is not alinged with size of "section", it can not
> be truncated?
IMO, the pinned file can only be truncated to section-aligned size.
Thanks
> thanks！
>> }
>>
>> err = setattr_prepare(idmap, dentry, attr);
>> ---
>>
>>>>
>>>> By doing this, pin+fallocate failure(gc happens EAGAIN but f2fs shows
>>>> enough spare space) may occurs.
>>>>
>>>> From message in commit 2e42b7f817ac("f2fs: stop allocating pinned sections
>>>> if EAGAIN happens"), gc EAGAIN doesn't guarantee a free section, so we stop
>>>> allocating. But after commit 48ea8b200414 ("f2fs: fix to avoid panic once
>>>> fallocation fails for pinfile"), we have a way to avoid panic caused by
>>>> concurrent pinfile allocation run out of free section, so I think that we
>>>> can continue to allocate pinned section when gc happens EAGAIN. Even if we
>>>> don't have free section, f2fs_allocate_pinning_section() can fail with ENOSPC.
>>>
>>> What do you think of introduce /sys/fs/f2fs/<dev>/reserved_pin_section to
>>> tune @needed parameter of has_not_enough_free_secs()? If we configure it
>>> w/ zero, it can avoid f2fs_gc() before preallocation.
>>>
>>> ---
>>> fs/f2fs/f2fs.h | 3 +++
>>> fs/f2fs/file.c | 5 ++---
>>> fs/f2fs/super.c | 3 +++
>>> fs/f2fs/sysfs.c | 9 +++++++++
>>> 4 files changed, 17 insertions(+), 3 deletions(-)
>>>
>>> diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
>>> index 785537576aa8..ffb15da570d7 100644
>>> --- a/fs/f2fs/f2fs.h
>>> +++ b/fs/f2fs/f2fs.h
>>> @@ -1731,6 +1731,9 @@ struct f2fs_sb_info {
>>> /* for skip statistic */
>>> unsigned long long skipped_gc_rwsem; /* FG_GC only */
>>>
>>> + /* free sections reserved for pinned file */
>>> + unsigned int reserved_pin_section;
>>> +
>>> /* threshold for gc trials on pinned files */
>>> unsigned short gc_pin_file_threshold;
>>> struct f2fs_rwsem pin_sem;
>>> diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
>>> index 696131e655ed..a909f79db178 100644
>>> --- a/fs/f2fs/file.c
>>> +++ b/fs/f2fs/file.c
>>> @@ -1887,9 +1887,8 @@ static int f2fs_expand_inode_data(struct inode *inode, loff_t offset,
>>> }
>>> }
>>>
>>> - if (has_not_enough_free_secs(sbi, 0, f2fs_sb_has_blkzoned(sbi) ?
>>> - ZONED_PIN_SEC_REQUIRED_COUNT :
>>> - GET_SEC_FROM_SEG(sbi, overprovision_segments(sbi)))) {
>>> + if (has_not_enough_free_secs(sbi, 0,
>>> + sbi->reserved_pin_section)) {
>>> f2fs_down_write(&sbi->gc_lock);
>>> stat_inc_gc_call_count(sbi, FOREGROUND);
>>> err = f2fs_gc(sbi, &gc_control);
>>> diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
>>> index 57adeff5ef25..48b97a95fd63 100644
>>> --- a/fs/f2fs/super.c
>>> +++ b/fs/f2fs/super.c
>>> @@ -4975,6 +4975,9 @@ static int f2fs_fill_super(struct super_block *sb, struct fs_context *fc)
>>> sbi->last_valid_block_count = sbi->total_valid_block_count;
>>> sbi->reserved_blocks = 0;
>>> sbi->current_reserved_blocks = 0;
>>> + sbi->reserved_pin_section = f2fs_sb_has_blkzoned(sbi) ?
>>> + ZONED_PIN_SEC_REQUIRED_COUNT :
>>> + GET_SEC_FROM_SEG(sbi, overprovision_segments(sbi));
>>> limit_reserve_root(sbi);
>>> adjust_unusable_cap_perc(sbi);
>>>
>>> diff --git a/fs/f2fs/sysfs.c b/fs/f2fs/sysfs.c
>>> index 75134d69a0bd..51be7ffb38c5 100644
>>> --- a/fs/f2fs/sysfs.c
>>> +++ b/fs/f2fs/sysfs.c
>>> @@ -824,6 +824,13 @@ static ssize_t __sbi_store(struct f2fs_attr *a,
>>> return count;
>>> }
>>>
>>> + if (!strcmp(a->attr.name, "reserved_pin_section")) {
>>> + if (t > GET_SEC_FROM_SEG(sbi, overprovision_segments(sbi)))
>>> + return -EINVAL;
>>> + *ui = (unsigned int)t;
>>> + return count;
>>> + }
>>> +
>>> *ui = (unsigned int)t;
>>>
>>> return count;
>>> @@ -1130,6 +1137,7 @@ F2FS_SBI_GENERAL_RO_ATTR(unusable_blocks_per_sec);
>>> F2FS_SBI_GENERAL_RW_ATTR(blkzone_alloc_policy);
>>> #endif
>>> F2FS_SBI_GENERAL_RW_ATTR(carve_out);
>>> +F2FS_SBI_GENERAL_RW_ATTR(reserved_pin_section);
>>>
>>> /* STAT_INFO ATTR */
>>> #ifdef CONFIG_F2FS_STAT_FS
>>> @@ -1323,6 +1331,7 @@ static struct attribute *f2fs_attrs[] = {
>>> ATTR_LIST(last_age_weight),
>>> ATTR_LIST(max_read_extent_count),
>>> ATTR_LIST(carve_out),
>>> + ATTR_LIST(reserved_pin_section),
>>> NULL,
>>> };
>>> ATTRIBUTE_GROUPS(f2fs);
>>> --
>>> 2.49.0
>>
>> I think it's a good way to solve this problem. Thank you!
>>
>>
>>>>
>>>> [1] https://lore.kernel.org/linux-f2fs-devel/20231030094024.263707-1-bo.wu@vivo.com/t/#u
>>>>
>>>> Signed-off-by: wangzijie <wangzijie1@honor.com>
>>>> ---
>>>> fs/f2fs/file.c | 2 +-
>>>> 1 file changed, 1 insertion(+), 1 deletion(-)
>>>>
>>>> diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
>>>> index 6bd3de64f..05c80d2b5 100644
>>>> --- a/fs/f2fs/file.c
>>>> +++ b/fs/f2fs/file.c
>>>> @@ -1859,7 +1859,7 @@ static int f2fs_expand_inode_data(struct inode *inode, loff_t offset,
>>>> f2fs_down_write(&sbi->gc_lock);
>>>> stat_inc_gc_call_count(sbi, FOREGROUND);
>>>> err = f2fs_gc(sbi, &gc_control);
>>>> - if (err && err != -ENODATA) {
>>>> + if (err && err != -ENODATA && err != -EAGAIN) {
>>>> f2fs_up_write(&sbi->pin_sem);
>>>> goto out_err;
>>>> }
>>>
>>>
>>>
>>> _______________________________________________
>>> Linux-f2fs-devel mailing list
>>> Linux-f2fs-devel@lists.sourceforge.net
>>> https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel
>>
>>
>>
>> _______________________________________________
>> Linux-f2fs-devel mailing list
>> Linux-f2fs-devel@lists.sourceforge.net
>> https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel
>
>
> _______________________________________________
> Linux-f2fs-devel mailing list
> Linux-f2fs-devel@lists.sourceforge.net
> https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel
_______________________________________________
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^ permalink raw reply [flat|nested] 7+ messages in thread
end of thread, other threads:[~2025-06-13 8:49 UTC | newest]
Thread overview: 7+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2025-06-12 3:27 [f2fs-dev] [PATCH] f2fs: continue to allocate pinned section when gc happens EAGAIN wangzijie
2025-06-12 8:31 ` Chao Yu via Linux-f2fs-devel
2025-06-12 12:34 ` wangzijie
2025-06-12 14:07 ` Chao Yu via Linux-f2fs-devel
2025-06-13 2:03 ` wangzijie
2025-06-13 8:25 ` Zhiguo Niu
2025-06-13 8:49 ` Chao Yu via Linux-f2fs-devel
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