Messages in this thread | | | Date | Fri, 30 Sep 2022 06:54:48 +0800 | Subject | Re: [f2fs-dev] [PATCH v2] f2fs: introduce F2FS_IOC_START_ATOMIC_REPLACE | From | Chao Yu <> |
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On 2022/9/30 0:13, Daeho Jeong wrote: > On Thu, Sep 29, 2022 at 12:36 AM Chao Yu <chao@kernel.org> wrote: >> >> On 2022/9/20 9:40, 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> >>> --- >>> v2: add undefined ioctl number reported by <lkp@intel.com> >>> --- >>> fs/f2fs/data.c | 3 +++ >>> fs/f2fs/f2fs.h | 1 + >>> fs/f2fs/file.c | 12 ++++++++++-- >>> fs/f2fs/segment.c | 14 +++++++++++++- >>> include/uapi/linux/f2fs.h | 1 + >>> 5 files changed, 28 insertions(+), 3 deletions(-) >>> >>> diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c >>> index 6cd29a575105..d3d32db3a25d 100644 >>> --- a/fs/f2fs/data.c >>> +++ b/fs/f2fs/data.c >>> @@ -3438,6 +3438,9 @@ 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 539da7f12cfc..2c49da12d6d8 100644 >>> --- a/fs/f2fs/f2fs.h >>> +++ b/fs/f2fs/f2fs.h >>> @@ -764,6 +764,7 @@ enum { >>> FI_COMPRESS_RELEASED, /* compressed blocks were released */ >>> FI_ALIGNED_WRITE, /* enable aligned write */ >>> FI_COW_FILE, /* indicate COW file */ >>> + 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 4f9b80c41b1e..4abd9d2a55b3 100644 >>> --- a/fs/f2fs/file.c >>> +++ b/fs/f2fs/file.c >>> @@ -1982,7 +1982,7 @@ 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); >>> @@ -2051,6 +2051,12 @@ static int f2fs_ioc_start_atomic_write(struct file *filp) >>> >>> 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; >>> + } >> >> Hi Daeho, >> >> isize should be updated after tagging inode as atomic_write one? >> otherwise f2fs_mark_inode_dirty_sync() may update isize to inode page, >> latter checkpoint may persist that change? IIUC... >> >> Thanks, > > Hi Chao, > > The first patch of this patchset prevents the inode page from being > updated as dirty for atomic file cases. > Is there any other chances for the inode page to be marked as dirty?
I mean:
Thread A Thread B - f2fs_ioc_start_atomic_write - f2fs_i_size_write(inode, 0) - f2fs_mark_inode_dirty_sync - checkpoint - persist inode with incorrect zero isize
- set_inode_flag(inode, FI_ATOMIC_FILE)
Am I missing something?
Thanks,
> > Thanks, > >> >>> f2fs_i_size_write(fi->cow_inode, isize); >>> >>> spin_lock(&sbi->inode_lock[ATOMIC_FILE]); >>> @@ -4080,7 +4086,9 @@ 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 143b7ea0fb8e..c524538a9013 100644 >>> --- a/fs/f2fs/segment.c >>> +++ b/fs/f2fs/segment.c >>> @@ -263,14 +263,26 @@ 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; >>> + } >>> + >>> list_del(&cur->list); >>> kmem_cache_free(revoke_entry_slab, cur); >>> } >>> + >>> + if (!revoke && truncate) { >>> + f2fs_do_truncate_blocks(inode, start_index * PAGE_SIZE, false); >>> + clear_inode_flag(inode, FI_ATOMIC_REPLACE); >>> + } >>> } >>> >>> 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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