* [PATCH] f2fs: fix to avoid potential section-unaligned pinfile
@ 2026-06-29 11:49 Chao Yu
2026-06-30 8:50 ` [f2fs-dev] " Zhiguo Niu
0 siblings, 1 reply; 4+ messages in thread
From: Chao Yu @ 2026-06-29 11:49 UTC (permalink / raw)
To: jaegeuk; +Cc: linux-f2fs-devel, linux-kernel, Chao Yu, stable, Daeho Jeong
Blocks of pinfile may not aligned to section size due to wrong use
on pinfile, result in heavy overhead of GC, let avoid this by
adding additional check condition in f2fs_setattr().
- truncate -s 8mb pinfile
: random checkpoint may persist filesize w/ inode
- fallocate -o 0 -l 8mb pinfile
- f2fs_fallocate
- f2fs_expand_inode_data
- f2fs_allocate_pinning_section
- f2fs_map_blocks
- f2fs_map_lock
- __allocate_data_block
- file_need_truncate
: w/ FADVISE_TRUNC_BIT, we can expect unaligned mapping can be
truncated while open() if f2fs is not umount abnormally
- f2fs_map_unlock
: following f2fs checkpoint and sudden power-cut
- mount
- open pinfile
- f2fs_file_open
- finish_preallocate_blocks
- truncate_setsize
: filesize is 8mb
- f2fs_truncate
: can only truncate block outside filesize, rather than truncating
unaligned blocks inside filesize
Fixes: f5a53edcf01e ("f2fs: support aligned pinned file")
Cc: stable@kernel.org
Cc: Daeho Jeong <daehojeong@google.com>
Signed-off-by: Chao Yu <chao@kernel.org>
---
fs/f2fs/file.c | 28 +++++++++++++++++-----------
1 file changed, 17 insertions(+), 11 deletions(-)
diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
index f4facd409d9b..11cc8d79c235 100644
--- a/fs/f2fs/file.c
+++ b/fs/f2fs/file.c
@@ -1107,17 +1107,23 @@ 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;
- /*
- * To prevent scattered pin block generation, we don't allow
- * smaller/equal size unaligned truncation for pinned file.
- * We only support overwrite IO to pinned file, so don't
- * care about larger size truncation.
- */
- if (f2fs_is_pinned_file(inode) &&
- attr->ia_size <= i_size_read(inode) &&
- !IS_ALIGNED(attr->ia_size,
- F2FS_BLK_TO_BYTES(CAP_BLKS_PER_SEC(sbi))))
- return -EINVAL;
+
+ if (f2fs_is_pinned_file(inode)) {
+ /*
+ * It may break section-aligned fallocate recovery
+ * mechanism, so do not allow larger size truncation.
+ */
+ if (attr->ia_size > i_size_read(inode))
+ return -EINVAL;
+ /*
+ * To prevent scattered pin block generation, we don't
+ * allow smaller/equal size unaligned truncation for
+ * pinned file.
+ */
+ else if (!IS_ALIGNED(attr->ia_size,
+ F2FS_BLK_TO_BYTES(CAP_BLKS_PER_SEC(sbi))))
+ return -EINVAL;
+ }
}
if (is_quota_modification(idmap, inode, attr)) {
--
2.49.0
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [f2fs-dev] [PATCH] f2fs: fix to avoid potential section-unaligned pinfile
2026-06-29 11:49 [PATCH] f2fs: fix to avoid potential section-unaligned pinfile Chao Yu
@ 2026-06-30 8:50 ` Zhiguo Niu
2026-06-30 11:02 ` Chao Yu
0 siblings, 1 reply; 4+ messages in thread
From: Zhiguo Niu @ 2026-06-30 8:50 UTC (permalink / raw)
To: Chao Yu; +Cc: jaegeuk, stable, Daeho Jeong, linux-kernel, linux-f2fs-devel
Chao Yu via Linux-f2fs-devel <linux-f2fs-devel@lists.sourceforge.net>
于2026年6月29日周一 19:52写道：
>
> Blocks of pinfile may not aligned to section size due to wrong use
> on pinfile, result in heavy overhead of GC, let avoid this by
> adding additional check condition in f2fs_setattr().
>
> - truncate -s 8mb pinfile
> : random checkpoint may persist filesize w/ inode
> - fallocate -o 0 -l 8mb pinfile
> - f2fs_fallocate
> - f2fs_expand_inode_data
> - f2fs_allocate_pinning_section
> - f2fs_map_blocks
> - f2fs_map_lock
> - __allocate_data_block
> - file_need_truncate
> : w/ FADVISE_TRUNC_BIT, we can expect unaligned mapping can be
> truncated while open() if f2fs is not umount abnormally
> - f2fs_map_unlock
> : following f2fs checkpoint and sudden power-cut
>
> - mount
> - open pinfile
> - f2fs_file_open
> - finish_preallocate_blocks
> - truncate_setsize
> : filesize is 8mb
> - f2fs_truncate
> : can only truncate block outside filesize, rather than truncating
> unaligned blocks inside filesize
Hi Chao,
8MB is section alinged when fallocated by f2fs_allocate_pinning_section??
so How could there are unaligned blocks inside filesize?
>
> Fixes: f5a53edcf01e ("f2fs: support aligned pinned file")
> Cc: stable@kernel.org
> Cc: Daeho Jeong <daehojeong@google.com>
> Signed-off-by: Chao Yu <chao@kernel.org>
> ---
> fs/f2fs/file.c | 28 +++++++++++++++++-----------
> 1 file changed, 17 insertions(+), 11 deletions(-)
>
> diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
> index f4facd409d9b..11cc8d79c235 100644
> --- a/fs/f2fs/file.c
> +++ b/fs/f2fs/file.c
> @@ -1107,17 +1107,23 @@ 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;
> - /*
> - * To prevent scattered pin block generation, we don't allow
> - * smaller/equal size unaligned truncation for pinned file.
> - * We only support overwrite IO to pinned file, so don't
> - * care about larger size truncation.
> - */
> - if (f2fs_is_pinned_file(inode) &&
> - attr->ia_size <= i_size_read(inode) &&
> - !IS_ALIGNED(attr->ia_size,
> - F2FS_BLK_TO_BYTES(CAP_BLKS_PER_SEC(sbi))))
> - return -EINVAL;
> +
> + if (f2fs_is_pinned_file(inode)) {
> + /*
> + * It may break section-aligned fallocate recovery
> + * mechanism, so do not allow larger size truncation.
> + */
> + if (attr->ia_size > i_size_read(inode))
> + return -EINVAL;
Is it ok if we allow larger size truncation and also limit it to
aligned "F2FS_BLK_TO_BYTES(CAP_BLKS_PER_SEC(sbi)"?
thanks!
> + /*
> + * To prevent scattered pin block generation, we don't
> + * allow smaller/equal size unaligned truncation for
> + * pinned file.
> + */
> + else if (!IS_ALIGNED(attr->ia_size,
> + F2FS_BLK_TO_BYTES(CAP_BLKS_PER_SEC(sbi))))
> + return -EINVAL;
> + }
> }
>
> if (is_quota_modification(idmap, inode, attr)) {
> --
> 2.49.0
>
>
>
> _______________________________________________
> 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] 4+ messages in thread
* Re: [f2fs-dev] [PATCH] f2fs: fix to avoid potential section-unaligned pinfile
2026-06-30 8:50 ` [f2fs-dev] " Zhiguo Niu
@ 2026-06-30 11:02 ` Chao Yu
2026-07-01 3:26 ` Zhiguo Niu
0 siblings, 1 reply; 4+ messages in thread
From: Chao Yu @ 2026-06-30 11:02 UTC (permalink / raw)
To: Zhiguo Niu
Cc: chao, jaegeuk, stable, Daeho Jeong, linux-kernel,
linux-f2fs-devel
On 6/30/26 16:50, Zhiguo Niu wrote:
> Chao Yu via Linux-f2fs-devel <linux-f2fs-devel@lists.sourceforge.net>
> 于2026年6月29日周一 19:52写道：
>>
>> Blocks of pinfile may not aligned to section size due to wrong use
>> on pinfile, result in heavy overhead of GC, let avoid this by
>> adding additional check condition in f2fs_setattr().
>>
>> - truncate -s 8mb pinfile
>> : random checkpoint may persist filesize w/ inode
>> - fallocate -o 0 -l 8mb pinfile
>> - f2fs_fallocate
>> - f2fs_expand_inode_data
>> - f2fs_allocate_pinning_section
>> - f2fs_map_blocks
>> - f2fs_map_lock
>> - __allocate_data_block
>> - file_need_truncate
>> : w/ FADVISE_TRUNC_BIT, we can expect unaligned mapping can be
>> truncated while open() if f2fs is not umount abnormally
>> - f2fs_map_unlock
>> : following f2fs checkpoint and sudden power-cut
>>
>> - mount
>> - open pinfile
>> - f2fs_file_open
>> - finish_preallocate_blocks
>> - truncate_setsize
>> : filesize is 8mb
>> - f2fs_truncate
>> : can only truncate block outside filesize, rather than truncating
>> unaligned blocks inside filesize
> Hi Chao,
> 8MB is section alinged when fallocated by f2fs_allocate_pinning_section??
> so How could there are unaligned blocks inside filesize?
Zhiguo,
As partial blkaddrs were persisted and recovered, see comments around
f2fs_map_unlock().
>>
>> Fixes: f5a53edcf01e ("f2fs: support aligned pinned file")
>> Cc: stable@kernel.org
>> Cc: Daeho Jeong <daehojeong@google.com>
>> Signed-off-by: Chao Yu <chao@kernel.org>
>> ---
>> fs/f2fs/file.c | 28 +++++++++++++++++-----------
>> 1 file changed, 17 insertions(+), 11 deletions(-)
>>
>> diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
>> index f4facd409d9b..11cc8d79c235 100644
>> --- a/fs/f2fs/file.c
>> +++ b/fs/f2fs/file.c
>> @@ -1107,17 +1107,23 @@ 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;
>> - /*
>> - * To prevent scattered pin block generation, we don't allow
>> - * smaller/equal size unaligned truncation for pinned file.
>> - * We only support overwrite IO to pinned file, so don't
>> - * care about larger size truncation.
>> - */
>> - if (f2fs_is_pinned_file(inode) &&
>> - attr->ia_size <= i_size_read(inode) &&
>> - !IS_ALIGNED(attr->ia_size,
>> - F2FS_BLK_TO_BYTES(CAP_BLKS_PER_SEC(sbi))))
>> - return -EINVAL;
>> +
>> + if (f2fs_is_pinned_file(inode)) {
>> + /*
>> + * It may break section-aligned fallocate recovery
>> + * mechanism, so do not allow larger size truncation.
>> + */
>> + if (attr->ia_size > i_size_read(inode))
>> + return -EINVAL;
> Is it ok if we allow larger size truncation and also limit it to
> aligned "F2FS_BLK_TO_BYTES(CAP_BLKS_PER_SEC(sbi)"?
No, I think above example will still suffer section-unaligned issue.
Thanks,
> thanks!
>> + /*
>> + * To prevent scattered pin block generation, we don't
>> + * allow smaller/equal size unaligned truncation for
>> + * pinned file.
>> + */
>> + else if (!IS_ALIGNED(attr->ia_size,
>> + F2FS_BLK_TO_BYTES(CAP_BLKS_PER_SEC(sbi))))
>> + return -EINVAL;
>> + }
>> }
>>
>> if (is_quota_modification(idmap, inode, attr)) {
>> --
>> 2.49.0
>>
>>
>>
>> _______________________________________________
>> 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] 4+ messages in thread
* Re: [f2fs-dev] [PATCH] f2fs: fix to avoid potential section-unaligned pinfile
2026-06-30 11:02 ` Chao Yu
@ 2026-07-01 3:26 ` Zhiguo Niu
0 siblings, 0 replies; 4+ messages in thread
From: Zhiguo Niu @ 2026-07-01 3:26 UTC (permalink / raw)
To: Chao Yu; +Cc: jaegeuk, stable, Daeho Jeong, linux-kernel, linux-f2fs-devel
Chao Yu <chao@kernel.org> 于2026年6月30日周二 19:02写道：
>
> On 6/30/26 16:50, Zhiguo Niu wrote:
> > Chao Yu via Linux-f2fs-devel <linux-f2fs-devel@lists.sourceforge.net>
> > 于2026年6月29日周一 19:52写道：
> >>
> >> Blocks of pinfile may not aligned to section size due to wrong use
> >> on pinfile, result in heavy overhead of GC, let avoid this by
> >> adding additional check condition in f2fs_setattr().
> >>
> >> - truncate -s 8mb pinfile
> >> : random checkpoint may persist filesize w/ inode
> >> - fallocate -o 0 -l 8mb pinfile
> >> - f2fs_fallocate
> >> - f2fs_expand_inode_data
> >> - f2fs_allocate_pinning_section
> >> - f2fs_map_blocks
> >> - f2fs_map_lock
> >> - __allocate_data_block
> >> - file_need_truncate
> >> : w/ FADVISE_TRUNC_BIT, we can expect unaligned mapping can be
> >> truncated while open() if f2fs is not umount abnormally
> >> - f2fs_map_unlock
> >> : following f2fs checkpoint and sudden power-cut
> >>
> >> - mount
> >> - open pinfile
> >> - f2fs_file_open
> >> - finish_preallocate_blocks
> >> - truncate_setsize
> >> : filesize is 8mb
> >> - f2fs_truncate
> >> : can only truncate block outside filesize, rather than truncating
> >> unaligned blocks inside filesize
> > Hi Chao,
> > 8MB is section alinged when fallocated by f2fs_allocate_pinning_section??
> > so How could there are unaligned blocks inside filesize?
>
> Zhiguo,
>
> As partial blkaddrs were persisted and recovered, see comments around
> f2fs_map_unlock().
>
> >>
> >> Fixes: f5a53edcf01e ("f2fs: support aligned pinned file")
> >> Cc: stable@kernel.org
> >> Cc: Daeho Jeong <daehojeong@google.com>
> >> Signed-off-by: Chao Yu <chao@kernel.org>
> >> ---
> >> fs/f2fs/file.c | 28 +++++++++++++++++-----------
> >> 1 file changed, 17 insertions(+), 11 deletions(-)
> >>
> >> diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
> >> index f4facd409d9b..11cc8d79c235 100644
> >> --- a/fs/f2fs/file.c
> >> +++ b/fs/f2fs/file.c
> >> @@ -1107,17 +1107,23 @@ 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;
> >> - /*
> >> - * To prevent scattered pin block generation, we don't allow
> >> - * smaller/equal size unaligned truncation for pinned file.
> >> - * We only support overwrite IO to pinned file, so don't
> >> - * care about larger size truncation.
> >> - */
> >> - if (f2fs_is_pinned_file(inode) &&
> >> - attr->ia_size <= i_size_read(inode) &&
> >> - !IS_ALIGNED(attr->ia_size,
> >> - F2FS_BLK_TO_BYTES(CAP_BLKS_PER_SEC(sbi))))
> >> - return -EINVAL;
> >> +
> >> + if (f2fs_is_pinned_file(inode)) {
> >> + /*
> >> + * It may break section-aligned fallocate recovery
> >> + * mechanism, so do not allow larger size truncation.
> >> + */
> >> + if (attr->ia_size > i_size_read(inode))
> >> + return -EINVAL;
> > Is it ok if we allow larger size truncation and also limit it to
> > aligned "F2FS_BLK_TO_BYTES(CAP_BLKS_PER_SEC(sbi)"?
>
> No, I think above example will still suffer section-unaligned issue.
>
> Thanks,
Hi Chao,
got it and thanks for your explaination, so
Reviewed-by: Zhiguo Niu <zhiguo.niu@unisoc.com>
thanks!
>
> > thanks!
> >> + /*
> >> + * To prevent scattered pin block generation, we don't
> >> + * allow smaller/equal size unaligned truncation for
> >> + * pinned file.
> >> + */
> >> + else if (!IS_ALIGNED(attr->ia_size,
> >> + F2FS_BLK_TO_BYTES(CAP_BLKS_PER_SEC(sbi))))
> >> + return -EINVAL;
> >> + }
> >> }
> >>
> >> if (is_quota_modification(idmap, inode, attr)) {
> >> --
> >> 2.49.0
> >>
> >>
> >>
> >> _______________________________________________
> >> 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] 4+ messages in thread
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2026-06-29 11:49 [PATCH] f2fs: fix to avoid potential section-unaligned pinfile Chao Yu
2026-06-30 8:50 ` [f2fs-dev] " Zhiguo Niu
2026-06-30 11:02 ` Chao Yu
2026-07-01 3:26 ` Zhiguo Niu
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