Case #1:
SQLite App GC Thread Kworker Shrinker
- f2fs_ioc_start_atomic_write
- f2fs_ioc_commit_atomic_write
- f2fs_commit_atomic_write
- filemap_write_and_wait_range
: write atomic_file's data to cow_inode
echo 3 >
drop_caches
to drop
atomic_file's
cache.
- f2fs_gc
- gc_data_segment
- move_data_page
- set_page_dirty
- writepages
- f2fs_do_write_data_page
: overwrite atomic_file's data
to cow_inode
- f2fs_down_write(&fi->i_gc_rwsem[WRITE])
- __f2fs_commit_atomic_write
- f2fs_up_write(&fi->i_gc_rwsem[WRITE])
Case #2:
SQLite App GC Thread Kworker
- f2fs_ioc_start_atomic_write
- __writeback_single_inode
- do_writepages
- f2fs_write_cache_pages
- f2fs_write_single_data_page
- f2fs_do_write_data_page
: write atomic_file's data
to cow_inode
- f2fs_gc
- gc_data_segment
- move_data_page
- set_page_dirty
- writepages
- f2fs_do_write_data_page
: overwrite atomic_file's data
to cow_inode
- f2fs_ioc_commit_atomic_write
In above cases racing in between atomic_write and GC, previous
data in atomic_file may be overwrited to cow_file, result in
data corruption.
This patch introduces PAGE_PRIVATE_ATOMIC_WRITE bit flag in page.private,
and use it to indicate that there is last dirty data in atomic file,
and the data should be writebacked into cow_file, if the flag is not
tagged in page, we should never write data across files.
Fixes: 3db1de0e582c ("f2fs: change the current atomic write way")
Cc: Daeho Jeong <daehoje...@google.com>
Signed-off-by: Chao Yu <c...@kernel.org>
---
fs/f2fs/data.c | 10 +++++++++-
fs/f2fs/f2fs.h | 8 +++++++-
2 files changed, 16 insertions(+), 2 deletions(-)
diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
index 0b4f563f2361..22031b9b507c 100644
--- a/fs/f2fs/data.c
+++ b/fs/f2fs/data.c
@@ -2647,10 +2647,13 @@ int f2fs_do_write_data_page(struct f2fs_io_info *fio)
struct dnode_of_data dn;
struct node_info ni;
bool ipu_force = false;
+ bool atomic_commit;
int err = 0;
/* Use COW inode to make dnode_of_data for atomic write */
- if (f2fs_is_atomic_file(inode))
+ atomic_commit = f2fs_is_atomic_file(inode) &&
+ page_private_atomic(fio->page);
+ if (atomic_commit)
set_new_dnode(&dn, F2FS_I(inode)->cow_inode, NULL, NULL, 0);
else
set_new_dnode(&dn, inode, NULL, NULL, 0);
@@ -2749,6 +2752,8 @@ int f2fs_do_write_data_page(struct f2fs_io_info *fio)
f2fs_outplace_write_data(&dn, fio);
trace_f2fs_do_write_data_page(page_folio(page), OPU);
set_inode_flag(inode, FI_APPEND_WRITE);
+ if (atomic_commit)
+ clear_page_private_atomic(page);
out_writepage:
f2fs_put_dnode(&dn);
out:
@@ -3718,6 +3723,9 @@ static int f2fs_write_end(struct file *file,
set_page_dirty(page);
+ if (f2fs_is_atomic_file(inode))
+ set_page_private_atomic(page);
+
if (pos + copied > i_size_read(inode) &&
!f2fs_verity_in_progress(inode)) {
f2fs_i_size_write(inode, pos + copied);
diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index 777497919c62..35dd2d45b0ed 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -1413,7 +1413,8 @@ static inline void f2fs_clear_bit(unsigned int nr, char
*addr);
* bit 1 PAGE_PRIVATE_ONGOING_MIGRATION
* bit 2 PAGE_PRIVATE_INLINE_INODE
* bit 3 PAGE_PRIVATE_REF_RESOURCE
- * bit 4- f2fs private data
+ * bit 4 PAGE_PRIVATE_ATOMIC_WRITE
+ * bit 5- f2fs private data
*
* Layout B: lowest bit should be 0
* page.private is a wrapped pointer.
@@ -1423,6 +1424,7 @@ enum {
PAGE_PRIVATE_ONGOING_MIGRATION, /* data page which is on-going
migrating */
PAGE_PRIVATE_INLINE_INODE, /* inode page contains inline
data */
PAGE_PRIVATE_REF_RESOURCE, /* dirty page has referenced
resources */
+ PAGE_PRIVATE_ATOMIC_WRITE, /* data page from atomic write
path */
PAGE_PRIVATE_MAX
};
@@ -2401,14 +2403,17 @@ static inline void clear_page_private_##name(struct
page *page) \
PAGE_PRIVATE_GET_FUNC(nonpointer, NOT_POINTER);
PAGE_PRIVATE_GET_FUNC(inline, INLINE_INODE);
PAGE_PRIVATE_GET_FUNC(gcing, ONGOING_MIGRATION);
+PAGE_PRIVATE_GET_FUNC(atomic, ATOMIC_WRITE);
PAGE_PRIVATE_SET_FUNC(reference, REF_RESOURCE);
PAGE_PRIVATE_SET_FUNC(inline, INLINE_INODE);
PAGE_PRIVATE_SET_FUNC(gcing, ONGOING_MIGRATION);
+PAGE_PRIVATE_SET_FUNC(atomic, ATOMIC_WRITE);
PAGE_PRIVATE_CLEAR_FUNC(reference, REF_RESOURCE);
PAGE_PRIVATE_CLEAR_FUNC(inline, INLINE_INODE);
PAGE_PRIVATE_CLEAR_FUNC(gcing, ONGOING_MIGRATION);
+PAGE_PRIVATE_CLEAR_FUNC(atomic, ATOMIC_WRITE);
static inline unsigned long get_page_private_data(struct page *page)
{
@@ -2440,6 +2445,7 @@ static inline void clear_page_private_all(struct page
*page)
clear_page_private_reference(page);
clear_page_private_gcing(page);
clear_page_private_inline(page);
+ clear_page_private_atomic(page);
f2fs_bug_on(F2FS_P_SB(page), page_private(page));
}
--
2.40.1
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