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f2fs: fix to add refcount once page is tagged PG_private 

As Gao Xiang reported in bugzilla:

https://bugzilla.kernel.org/show_bug.cgi?id=202749

f2fs may skip pageout() due to incorrect page reference count.

The problem here is that MM defined the rule [1] very clearly that
once page was set with PG_private flag, we should increment the
refcount in that page, also main flows like pageout(), migrate_page()
will assume there is one additional page reference count if
page_has_private() returns true.

But currently, f2fs won't add/del refcount when changing PG_private
flag. Anyway, f2fs should follow MM's rule to make MM's related flows
running as expected.

[1] https://lore.kernel.org/lkml/2b19b3c4-2bc4-15fa-15cc-27a13e5c7af1@aol.com/

Reported-by: Gao Xiang <gaoxiang25@huawei.com>
Signed-off-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
This commit is contained in:
Chao Yu 2019-03-06 17:30:59 +08:00 committed by Jaegeuk Kim
parent 25720cc05e
commit 240a59156d
6 changed files with 36 additions and 23 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

4
fs/f2fs/checkpoint.c
View File

@ -406,7 +406,7 @@ static int f2fs_set_meta_page_dirty(struct page *page)
if (!PageDirty(page)) {
__set_page_dirty_nobuffers(page);
inc_page_count(F2FS_P_SB(page), F2FS_DIRTY_META);
SetPagePrivate(page);
f2fs_set_page_private(page, 0);
f2fs_trace_pid(page);
return 1;
}
@ -957,7 +957,7 @@ void f2fs_update_dirty_page(struct inode *inode, struct page *page)
inode_inc_dirty_pages(inode);
spin_unlock(&sbi->inode_lock[type]);
SetPagePrivate(page);
f2fs_set_page_private(page, 0);
f2fs_trace_pid(page);
}

21
fs/f2fs/data.c
View File

@ -2714,8 +2714,7 @@ void f2fs_invalidate_page(struct page *page, unsigned int offset,
if (IS_ATOMIC_WRITTEN_PAGE(page))
return f2fs_drop_inmem_page(inode, page);
set_page_private(page, 0);
ClearPagePrivate(page);
f2fs_clear_page_private(page);
}
int f2fs_release_page(struct page *page, gfp_t wait)
@ -2729,8 +2728,7 @@ int f2fs_release_page(struct page *page, gfp_t wait)
return 0;
clear_cold_data(page);
set_page_private(page, 0);
ClearPagePrivate(page);
f2fs_clear_page_private(page);
return 1;
}
@ -2798,12 +2796,8 @@ int f2fs_migrate_page(struct address_space *mapping,
return -EAGAIN;
}
/*
* A reference is expected if PagePrivate set when move mapping,
* however F2FS breaks this for maintaining dirty page counts when
* truncating pages. So here adjusting the 'extra_count' make it work.
*/
extra_count = (atomic_written ? 1 : 0) - page_has_private(page);
/* one extra reference was held for atomic_write page */
extra_count = atomic_written ? 1 : 0;
rc = migrate_page_move_mapping(mapping, newpage,
page, mode, extra_count);
if (rc != MIGRATEPAGE_SUCCESS) {
@ -2824,9 +2818,10 @@ int f2fs_migrate_page(struct address_space *mapping,
get_page(newpage);
}
if (PagePrivate(page))
SetPagePrivate(newpage);
set_page_private(newpage, page_private(page));
if (PagePrivate(page)) {
f2fs_set_page_private(newpage, page_private(page));
f2fs_clear_page_private(page);
}
if (mode != MIGRATE_SYNC_NO_COPY)
migrate_page_copy(newpage, page);

2
fs/f2fs/dir.c
View File

@ -728,7 +728,7 @@ void f2fs_delete_entry(struct f2fs_dir_entry *dentry, struct page *page,
!f2fs_truncate_hole(dir, page->index, page->index + 1)) {
f2fs_clear_page_cache_dirty_tag(page);
clear_page_dirty_for_io(page);
ClearPagePrivate(page);
f2fs_clear_page_private(page);
ClearPageUptodate(page);
clear_cold_data(page);
inode_dec_dirty_pages(dir);

21
fs/f2fs/f2fs.h
View File

@ -2835,6 +2835,27 @@ static inline bool is_valid_data_blkaddr(struct f2fs_sb_info *sbi,
return true;
}
static inline void f2fs_set_page_private(struct page *page,
unsigned long data)
{
if (PagePrivate(page))
return;
get_page(page);
SetPagePrivate(page);
set_page_private(page, data);
}
static inline void f2fs_clear_page_private(struct page *page)
{
if (!PagePrivate(page))
return;
set_page_private(page, 0);
ClearPagePrivate(page);
f2fs_put_page(page, 0);
}
/*
* file.c
*/

2
fs/f2fs/node.c
View File

@ -1961,7 +1961,7 @@ static int f2fs_set_node_page_dirty(struct page *page)
if (!PageDirty(page)) {
__set_page_dirty_nobuffers(page);
inc_page_count(F2FS_P_SB(page), F2FS_DIRTY_NODES);
SetPagePrivate(page);
f2fs_set_page_private(page, 0);
f2fs_trace_pid(page);
return 1;
}

9
fs/f2fs/segment.c
View File

@ -191,8 +191,7 @@ void f2fs_register_inmem_page(struct inode *inode, struct page *page)
f2fs_trace_pid(page);
set_page_private(page, (unsigned long)ATOMIC_WRITTEN_PAGE);
SetPagePrivate(page);
f2fs_set_page_private(page, (unsigned long)ATOMIC_WRITTEN_PAGE);
new = f2fs_kmem_cache_alloc(inmem_entry_slab, GFP_NOFS);
@ -280,8 +279,7 @@ next:
ClearPageUptodate(page);
clear_cold_data(page);
}
set_page_private(page, 0);
ClearPagePrivate(page);
f2fs_clear_page_private(page);
f2fs_put_page(page, 1);
list_del(&cur->list);
@ -370,8 +368,7 @@ void f2fs_drop_inmem_page(struct inode *inode, struct page *page)
kmem_cache_free(inmem_entry_slab, cur);
ClearPageUptodate(page);
set_page_private(page, 0);
ClearPagePrivate(page);
f2fs_clear_page_private(page);
f2fs_put_page(page, 0);
trace_f2fs_commit_inmem_page(page, INMEM_INVALIDATE);