As Youling reported in mailing list:
https://www.linuxquestions.org/questions/linux-newbie-8/the-file-system-f2fs...
https://www.linux.org/threads/the-file-system-f2fs-is-broken.26490/
There is a test case can corrupt f2fs image: - dd if=/dev/zero of=/swapfile bs=1M count=4096 - chmod 600 /swapfile - mkswap /swapfile - swapon --discard /swapfile
The root cause is f2fs_swap_activate() intends to return zero value to setup_swap_extents() to enable SWP_FS mode (swap file goes through fs), in this flow, setup_swap_extents() setups swap extent with wrong block address range, result in discard_swap() erasing incorrect address.
Because f2fs_swap_activate() has pinned swapfile, its data block address will not change, it's safe to let swap to handle IO through raw device, so we can get rid of SWAP_FS mode and initial swap extents inside f2fs_swap_activate(), by this way, later discard_swap() can trim in right address range.
Fixes: 4969c06a0d83 ("f2fs: support swap file w/ DIO") Cc: stable@vger.kernel.org Signed-off-by: Chao Yu yuchao0@huawei.com Signed-off-by: Jaegeuk Kim jaegeuk@kernel.org --- fs/f2fs/data.c | 32 +++++++++++++++++++++++++------- 1 file changed, 25 insertions(+), 7 deletions(-)
diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c index 98c946dfee13..b56437d4973d 100644 --- a/fs/f2fs/data.c +++ b/fs/f2fs/data.c @@ -3627,7 +3627,8 @@ int f2fs_migrate_page(struct address_space *mapping,
#ifdef CONFIG_SWAP /* Copied from generic_swapfile_activate() to check any holes */ -static int check_swap_activate(struct file *swap_file, unsigned int max) +static int check_swap_activate(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; @@ -3638,6 +3639,8 @@ static int check_swap_activate(struct file *swap_file, unsigned int max) sector_t last_block; sector_t lowest_block = -1; sector_t highest_block = 0; + int nr_extents = 0; + int ret;
blkbits = inode->i_blkbits; blocks_per_page = PAGE_SIZE >> blkbits; @@ -3649,7 +3652,8 @@ static int check_swap_activate(struct file *swap_file, unsigned int max) probe_block = 0; page_no = 0; last_block = i_size_read(inode) >> blkbits; - while ((probe_block + blocks_per_page) <= last_block && page_no < max) { + while ((probe_block + blocks_per_page) <= last_block && + page_no < sis->max) { unsigned block_in_page; sector_t first_block;
@@ -3689,13 +3693,27 @@ static int check_swap_activate(struct file *swap_file, unsigned int max) highest_block = first_block; }
+ /* + * We found a PAGE_SIZE-length, PAGE_SIZE-aligned run of blocks + */ + ret = add_swap_extent(sis, page_no, 1, first_block); + if (ret < 0) + goto out; + nr_extents += ret; page_no++; probe_block += blocks_per_page; reprobe: continue; } - return 0; - + ret = nr_extents; + *span = 1 + highest_block - lowest_block; + if (page_no == 0) + page_no = 1; /* force Empty message */ + sis->max = page_no; + sis->pages = page_no - 1; + sis->highest_bit = page_no - 1; +out: + return ret; bad_bmap: pr_err("swapon: swapfile has holes\n"); return -EINVAL; @@ -3720,14 +3738,14 @@ static int f2fs_swap_activate(struct swap_info_struct *sis, struct file *file, if (f2fs_disable_compressed_file(inode)) return -EINVAL;
- ret = check_swap_activate(file, sis->max); - if (ret) + ret = check_swap_activate(sis, file, span); + if (ret < 0) return ret;
set_inode_flag(inode, FI_PIN_FILE); f2fs_precache_extents(inode); f2fs_update_time(F2FS_I_SB(inode), REQ_TIME); - return 0; + return ret; }
static void f2fs_swap_deactivate(struct file *file)