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 <huangjia...@oppo.com>
Signed-off-by: Guo Weichao <guoweic...@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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