As Youling reported in mailing list:
https://www.linuxquestions.org/questions/linux-newbie-8/the-file-system-f2fs-is-broken-4175666043/
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")
Signed-off-by: Chao Yu <[email protected]>
---
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 19cd03450066..ee4d3d284379 100644
--- a/fs/f2fs/data.c
+++ b/fs/f2fs/data.c
@@ -3608,7 +3608,8 @@ 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;
@@ -3619,6 +3620,8 @@ 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;
@@ -3630,7 +3633,8 @@ 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;
@@ -3670,13 +3674,27 @@ 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;
@@ -3701,14 +3719,14 @@ 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)
--
2.18.0.rc1
Hi Chao,
I think this should be sent to linux-stable.
Thoughts?
Thanks.
On Fri, Dec 27, 2019 at 7:45 PM Chao Yu <[email protected]> wrote:
>
> As Youling reported in mailing list:
>
> https://www.linuxquestions.org/questions/linux-newbie-8/the-file-system-f2fs-is-broken-4175666043/
>
> 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")
> Signed-off-by: Chao Yu <[email protected]>
> ---
> 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 19cd03450066..ee4d3d284379 100644
> --- a/fs/f2fs/data.c
> +++ b/fs/f2fs/data.c
> @@ -3608,7 +3608,8 @@ 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;
> @@ -3619,6 +3620,8 @@ 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;
> @@ -3630,7 +3633,8 @@ 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;
>
> @@ -3670,13 +3674,27 @@ 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;
> @@ -3701,14 +3719,14 @@ 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)
> --
> 2.18.0.rc1
>
>
>
> _______________________________________________
> Linux-f2fs-devel mailing list
> [email protected]
> https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel
Hi Ju Hyung,
On 2020/2/7 14:42, Ju Hyung Park wrote:
> Hi Chao,
>
> I think this should be sent to linux-stable.
> Thoughts?
Yup, I forgot to Cc stable mailing list, let me resend it.
Thanks for reminding me that.
Thanks,
>
> Thanks.
>
> On Fri, Dec 27, 2019 at 7:45 PM Chao Yu <[email protected]> wrote:
>>
>> As Youling reported in mailing list:
>>
>> https://www.linuxquestions.org/questions/linux-newbie-8/the-file-system-f2fs-is-broken-4175666043/
>>
>> 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")
>> Signed-off-by: Chao Yu <[email protected]>
>> ---
>> 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 19cd03450066..ee4d3d284379 100644
>> --- a/fs/f2fs/data.c
>> +++ b/fs/f2fs/data.c
>> @@ -3608,7 +3608,8 @@ 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;
>> @@ -3619,6 +3620,8 @@ 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;
>> @@ -3630,7 +3633,8 @@ 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;
>>
>> @@ -3670,13 +3674,27 @@ 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;
>> @@ -3701,14 +3719,14 @@ 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)
>> --
>> 2.18.0.rc1
>>
>>
>>
>> _______________________________________________
>> Linux-f2fs-devel mailing list
>> [email protected]
>> https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel
> .
>