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Subject[PATCH 3/3] f2fs: check if swapfile is section-alligned
Date
If the swapfile isn't created by pin and fallocate, it cann't be
guaranteed section-aligned, so it may be selected by f2fs gc. When
gc_pin_file_threshold is reached, the address of swapfile may change,
but won't be synchroniz to swap_extent, so swap will write to wrong
address, which will cause data corruption.

Signed-off-by: Huang Jianan <huangjianan@oppo.com>
Signed-off-by: Guo Weichao <guoweichao@oppo.com>
---
fs/f2fs/data.c | 63 ++++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 63 insertions(+)

diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
index 4dbc1cafc55d..3e523d6e4643 100644
--- a/fs/f2fs/data.c
+++ b/fs/f2fs/data.c
@@ -3781,11 +3781,63 @@ int f2fs_migrate_page(struct address_space *mapping,
#endif

#ifdef CONFIG_SWAP
+static int f2fs_check_file_aligned(struct inode *inode)
+{
+ struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
+ block_t main_blkaddr = SM_I(sbi)->main_blkaddr;
+ block_t cur_lblock;
+ block_t last_lblock;
+ block_t pblock;
+ unsigned long len;
+ unsigned long nr_pblocks;
+ unsigned int blocks_per_sec = sbi->blocks_per_seg * sbi->segs_per_sec;
+ int ret;
+
+ cur_lblock = 0;
+ last_lblock = bytes_to_blks(inode, i_size_read(inode));
+ len = i_size_read(inode);
+
+ while (cur_lblock < last_lblock) {
+ struct f2fs_map_blocks map;
+ pgoff_t next_pgofs;
+
+ memset(&map, 0, sizeof(map));
+ map.m_lblk = cur_lblock;
+ map.m_len = bytes_to_blks(inode, len) - cur_lblock;
+ map.m_next_pgofs = &next_pgofs;
+ map.m_seg_type = NO_CHECK_TYPE;
+
+ ret = f2fs_map_blocks(inode, &map, 0, F2FS_GET_BLOCK_FIEMAP);
+
+ if (ret)
+ goto err_out;
+
+ /* hole */
+ if (!(map.m_flags & F2FS_MAP_FLAGS))
+ goto err_out;
+
+ pblock = map.m_pblk;
+ nr_pblocks = map.m_len;
+
+ if ((pblock - main_blkaddr) & (blocks_per_sec - 1) ||
+ nr_pblocks & (blocks_per_sec - 1))
+ goto err_out;
+
+ cur_lblock += nr_pblocks;
+ }
+
+ return 0;
+err_out:
+ pr_err("swapon: swapfile isn't section-aligned\n");
+ return -EINVAL;
+}
+
static int check_swap_activate_fast(struct swap_info_struct *sis,
struct file *swap_file, sector_t *span)
{
struct address_space *mapping = swap_file->f_mapping;
struct inode *inode = mapping->host;
+ struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
sector_t cur_lblock;
sector_t last_lblock;
sector_t pblock;
@@ -3793,6 +3845,7 @@ static int check_swap_activate_fast(struct swap_info_struct *sis,
sector_t highest_pblock = 0;
int nr_extents = 0;
unsigned long nr_pblocks;
+ unsigned int blocks_per_sec = sbi->blocks_per_seg * sbi->segs_per_sec;
u64 len;
int ret;

@@ -3827,6 +3880,13 @@ static int check_swap_activate_fast(struct swap_info_struct *sis,
pblock = map.m_pblk;
nr_pblocks = map.m_len;

+ if ((pblock - SM_I(sbi)->main_blkaddr) & (blocks_per_sec - 1) ||
+ nr_pblocks & (blocks_per_sec - 1)) {
+ pr_err("swapon: swapfile isn't section-aligned\n");
+ ret = -EINVAL;
+ goto out;
+ }
+
if (cur_lblock + nr_pblocks >= sis->max)
nr_pblocks = sis->max - cur_lblock;

@@ -3878,6 +3938,9 @@ static int check_swap_activate(struct swap_info_struct *sis,
if (PAGE_SIZE == F2FS_BLKSIZE)
return check_swap_activate_fast(sis, swap_file, span);

+ if (f2fs_check_file_aligned(inode))
+ return -EINVAL;
+
blocks_per_page = bytes_to_blks(inode, PAGE_SIZE);

/*
--
2.25.1
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