Messages in this thread | | | Date | Wed, 23 Nov 2022 23:23:27 +0800 | Subject | Re: [f2fs-dev] [PATCH v7] f2fs: introduce F2FS_IOC_START_ATOMIC_REPLACE | From | Chao Yu <> |
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On 2022/11/12 1:04, Daeho Jeong wrote: > From: Daeho Jeong <daehojeong@google.com> > > introduce a new ioctl to replace the whole content of a file atomically, > which means it induces truncate and content update at the same time. > We can start it with F2FS_IOC_START_ATOMIC_REPLACE and complete it with > F2FS_IOC_COMMIT_ATOMIC_WRITE. Or abort it with > F2FS_IOC_ABORT_ATOMIC_WRITE. > > Signed-off-by: Daeho Jeong <daehojeong@google.com> > --- > v7: changed where to clear FI_ATOMIC_REPLACE > fixed tentative race condition in f2fs_ioc_start_atomic_write() > v3: move i_size change after setting atomic write flag > v2: add undefined ioctl number reported by <lkp@intel.com> > --- > fs/f2fs/data.c | 3 +++ > fs/f2fs/f2fs.h | 1 + > fs/f2fs/file.c | 21 +++++++++++++++------ > fs/f2fs/segment.c | 13 ++++++++++++- > include/uapi/linux/f2fs.h | 1 + > 5 files changed, 32 insertions(+), 7 deletions(-) > > diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c > index 5f895ddcd64a..bce4dcc3ad78 100644 > --- a/fs/f2fs/data.c > +++ b/fs/f2fs/data.c > @@ -3457,6 +3457,9 @@ static int prepare_atomic_write_begin(struct f2fs_sb_info *sbi, > else if (*blk_addr != NULL_ADDR) > return 0; > > + if (is_inode_flag_set(inode, FI_ATOMIC_REPLACE)) > + goto reserve_block; > + > /* Look for the block in the original inode */ > err = __find_data_block(inode, index, &ori_blk_addr); > if (err) > diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h > index e29f9adf60ca..d513ecd17550 100644 > --- a/fs/f2fs/f2fs.h > +++ b/fs/f2fs/f2fs.h > @@ -765,6 +765,7 @@ enum { > FI_ALIGNED_WRITE, /* enable aligned write */ > FI_COW_FILE, /* indicate COW file */ > FI_ATOMIC_COMMITTED, /* indicate atomic commit completed except disk sync */ > + FI_ATOMIC_REPLACE, /* indicate atomic replace */ > FI_MAX, /* max flag, never be used */ > }; > > diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c > index 7ce629c95f4a..f9a04f6d76cb 100644 > --- a/fs/f2fs/file.c > +++ b/fs/f2fs/file.c > @@ -1984,7 +1984,7 @@ static int f2fs_ioc_getversion(struct file *filp, unsigned long arg) > return put_user(inode->i_generation, (int __user *)arg); > } > > -static int f2fs_ioc_start_atomic_write(struct file *filp) > +static int f2fs_ioc_start_atomic_write(struct file *filp, bool truncate) > { > struct inode *inode = file_inode(filp); > struct user_namespace *mnt_userns = file_mnt_user_ns(filp); > @@ -2053,15 +2053,22 @@ static int f2fs_ioc_start_atomic_write(struct file *filp) > > f2fs_write_inode(inode, NULL); > > - isize = i_size_read(inode); > - fi->original_i_size = isize; > - f2fs_i_size_write(fi->cow_inode, isize); > - > stat_inc_atomic_inode(inode); > > set_inode_flag(inode, FI_ATOMIC_FILE); > set_inode_flag(fi->cow_inode, FI_COW_FILE); > clear_inode_flag(fi->cow_inode, FI_INLINE_DATA); > + > + isize = i_size_read(inode); > + fi->original_i_size = isize; > + if (truncate) { > + set_inode_flag(inode, FI_ATOMIC_REPLACE); > + truncate_inode_pages_final(inode->i_mapping); > + f2fs_i_size_write(inode, 0); > + isize = 0; > + } > + f2fs_i_size_write(fi->cow_inode, isize); > + > f2fs_up_write(&fi->i_gc_rwsem[WRITE]); > > f2fs_update_time(sbi, REQ_TIME); > @@ -4089,7 +4096,9 @@ static long __f2fs_ioctl(struct file *filp, unsigned int cmd, unsigned long arg) > case FS_IOC_GETVERSION: > return f2fs_ioc_getversion(filp, arg); > case F2FS_IOC_START_ATOMIC_WRITE: > - return f2fs_ioc_start_atomic_write(filp); > + return f2fs_ioc_start_atomic_write(filp, false); > + case F2FS_IOC_START_ATOMIC_REPLACE: > + return f2fs_ioc_start_atomic_write(filp, true); > case F2FS_IOC_COMMIT_ATOMIC_WRITE: > return f2fs_ioc_commit_atomic_write(filp); > case F2FS_IOC_ABORT_ATOMIC_WRITE: > diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c > index 9cbf88092c78..f2930fffbc7d 100644 > --- a/fs/f2fs/segment.c > +++ b/fs/f2fs/segment.c > @@ -197,6 +197,7 @@ void f2fs_abort_atomic_write(struct inode *inode, bool clean) > fi->cow_inode = NULL; > release_atomic_write_cnt(inode); > clear_inode_flag(inode, FI_ATOMIC_COMMITTED); > + clear_inode_flag(inode, FI_ATOMIC_REPLACE); > clear_inode_flag(inode, FI_ATOMIC_FILE); > stat_dec_atomic_inode(inode); > > @@ -261,14 +262,24 @@ static void __complete_revoke_list(struct inode *inode, struct list_head *head, > bool revoke) > { > struct revoke_entry *cur, *tmp; > + pgoff_t start_index = 0; > + bool truncate = is_inode_flag_set(inode, FI_ATOMIC_REPLACE); > > list_for_each_entry_safe(cur, tmp, head, list) { > - if (revoke) > + if (revoke) { > __replace_atomic_write_block(inode, cur->index, > cur->old_addr, NULL, true); > + } else if (truncate) { > + f2fs_truncate_hole(inode, start_index, cur->index); > + start_index = cur->index + 1;
Do we try to truncate from page #0 to page #(index of last page in chain)?
If so, how about calling f2fs_truncate_hole(, 0, last_index) after the loop?
Thanks,
> + } > + > list_del(&cur->list); > kmem_cache_free(revoke_entry_slab, cur); > } > + > + if (!revoke && truncate) > + f2fs_do_truncate_blocks(inode, start_index * PAGE_SIZE, false); > } > > static int __f2fs_commit_atomic_write(struct inode *inode) > diff --git a/include/uapi/linux/f2fs.h b/include/uapi/linux/f2fs.h > index 3121d127d5aa..955d440be104 100644 > --- a/include/uapi/linux/f2fs.h > +++ b/include/uapi/linux/f2fs.h > @@ -42,6 +42,7 @@ > struct f2fs_comp_option) > #define F2FS_IOC_DECOMPRESS_FILE _IO(F2FS_IOCTL_MAGIC, 23) > #define F2FS_IOC_COMPRESS_FILE _IO(F2FS_IOCTL_MAGIC, 24) > +#define F2FS_IOC_START_ATOMIC_REPLACE _IO(F2FS_IOCTL_MAGIC, 25) > > /* > * should be same as XFS_IOC_GOINGDOWN.
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