On 2022/11/12 1:04, Daeho Jeong wrote:
From: Daeho Jeong <daehoje...@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 <daehoje...@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 <l...@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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