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Date: Fri, 23 Jul 2021 09:34:59 +0800
From: Chao Yu <chao@...nel.org>
To: Daeho Jeong <daeho43@...il.com>
Cc: linux-kernel@...r.kernel.org,
linux-f2fs-devel@...ts.sourceforge.net, kernel-team@...roid.com,
Daeho Jeong <daehojeong@...gle.com>
Subject: Re: [f2fs-dev] [PATCH v2] f2fs: change fiemap way in printing
compression chunk
On 2021/7/23 8:49, Daeho Jeong wrote:
> On Thu, Jul 22, 2021 at 5:20 PM Chao Yu <chao@...nel.org> wrote:
>>
>> Hi Daeho,
>>
>> On 2021/7/23 5:19, Daeho Jeong wrote:
>>> From: Daeho Jeong <daehojeong@...gle.com>
>>>
>>> When we print out a discontinuous compression chunk, it shows like a
>>> continuous chunk now. To show it more correctly, I've changed the way of
>>> printing fiemap info like below. Plus, eliminated NEW_ADDR(-1) in fiemap
>>> info, since it is not in fiemap user api manual.
>>>
>>> Logical Physical Length Flags
>>> 0: 0000000000000000 0000000fdf692000 0000000000004000 1008
>>> 1: 0000000000004000 0000000fdf693000 0000000000004000 1008
>>> 2: 0000000000008000 0000000fdf694000 0000000000004000 1008
>>> 3: 000000000000c000 0000000fdf695000 0000000000004000 1008
>>> 4: 0000000000010000 0000000fdf696000 000000000000c000 1000
>>> 5: 000000000001c000 0000000f8c60d000 0000000000010000 1000
>>> 6: 000000000002c000 0000000f8c61d000 0000000000004000 1008
>>> 7: 0000000000030000 0000000f8c620000 0000000000004000 1008
>>> 8: 0000000000034000 0000000f8c623000 0000000000001000 1008
>>> 9: 0000000000035000 0000000fc7af4000 0000000000003000 1008
>>
>> I wrote a file some like this:
>>
>> i_addr[0x9] cluster flag [0xfffffffe : 4294967294]
>> i_addr[0xa] [0x 72800 : 468992]
>> i_addr[0xb] reserved flag [0xffffffff : 4294967295]
>> i_addr[0xc] reserved flag [0xffffffff : 4294967295]
>> i_addr[0xd] cluster flag [0xfffffffe : 4294967294]
>> i_addr[0xe] [0x 72801 : 468993]
>> i_addr[0xf] reserved flag [0xffffffff : 4294967295]
>> i_addr[0x10] reserved flag [0xffffffff : 4294967295]
>> i_addr[0x11] [0x 72832 : 469042]
>> i_addr[0x12] [0x 72802 : 468994]
>> i_addr[0x13] [0x 72833 : 469043]
>> i_addr[0x14] [0x 72834 : 469044]
>> i_addr[0x15] cluster flag [0xfffffffe : 4294967294]
>> i_addr[0x16] [0x 72803 : 468995]
>> i_addr[0x17] reserved flag [0xffffffff : 4294967295]
>> i_addr[0x18] reserved flag [0xffffffff : 4294967295]
>> i_addr[0x19] [0x 72835 : 469045]
>> i_addr[0x1a] [0x 72804 : 468996]
>> i_addr[0x1b] [0x 72836 : 469046]
>> i_addr[0x1c] [0x 72837 : 469047]
>> i_addr[0x1d] cluster flag [0xfffffffe : 4294967294]
>> i_addr[0x1e] [0x 72805 : 468997]
>> i_addr[0x1f] reserved flag [0xffffffff : 4294967295]
>> i_addr[0x20] reserved flag [0xffffffff : 4294967295]
>> i_addr[0x21] cluster flag [0xfffffffe : 4294967294]
>> i_addr[0x22] [0x 72806 : 468998]
>> i_addr[0x23] reserved flag [0xffffffff : 4294967295]
>> i_addr[0x24] reserved flag [0xffffffff : 4294967295]
>> i_addr[0x25] cluster flag [0xfffffffe : 4294967294]
>> i_addr[0x26] [0x 72807 : 468999]
>> i_addr[0x27] reserved flag [0xffffffff : 4294967295]
>> i_addr[0x28] reserved flag [0xffffffff : 4294967295]
>> i_addr[0x29] cluster flag [0xfffffffe : 4294967294]
>> i_addr[0x2a] [0x 72808 : 469000]
>> i_addr[0x2b] reserved flag [0xffffffff : 4294967295]
>> i_addr[0x2c] reserved flag [0xffffffff : 4294967295]
>> i_addr[0x2d] cluster flag [0xfffffffe : 4294967294]
>> i_addr[0x2e] [0x 72809 : 469001]
>> i_addr[0x2f] reserved flag [0xffffffff : 4294967295]
>> i_addr[0x30] reserved flag [0xffffffff : 4294967295]
>> i_nid[0] [0x 0 : 0]
>> i_nid[1] [0x 0 : 0]
>> i_nid[2] [0x 0 : 0]
>> i_nid[3] [0x 0 : 0]
>> i_nid[4] [0x 0 : 0]
>>
>> xfs_io file -c "fiemap -v" shows:
>>
>> before:
>> EXT: FILE-OFFSET BLOCK-RANGE TOTAL FLAGS
>> 0: [0..31]: 3751936..3751967 32 0x1008
>> 1: [32..63]: 3751944..3751975 32 0x1008
>> 2: [64..71]: 3752336..3752343 8 0x1000
>> 3: [72..79]: 3751952..3751959 8 0x1000
>> 4: [80..95]: 3752344..3752359 16 0x1000
>> 5: [96..127]: 3751960..3751991 32 0x1008
>> 6: [128..135]: 3752360..3752367 8 0x1000
>> 7: [136..143]: 3751968..3751975 8 0x1000
>> 8: [144..159]: 3752368..3752383 16 0x1000
>> 9: [160..191]: 3751976..3752007 32 0x1008
>> 10: [192..223]: 3751984..3752015 32 0x1008
>> 11: [224..255]: 3751992..3752023 32 0x1008
>> 12: [256..287]: 3752000..3752031 32 0x1008
>> 13: [288..319]: 3752008..3752039 32 0x1009
>>
>> after:
>> 0: [0..31]: 3751936..3751967 32 0x1008
>> 1: [32..63]: 3751944..3751975 32 0x1008
>> 2: [64..71]: 3752336..3752343 8 0x1000
>> 3: [72..79]: 3751952..3751959 8 0x1000
>> 4: [80..95]: 3752344..3752359 16 0x1000
>> 5: [96..127]: 3751960..3751991 32 0x1008
>> 6: [128..135]: 3752360..3752367 8 0x1000
>> 7: [136..143]: 3751968..3751975 8 0x1000
>> 8: [144..159]: 3752368..3752383 16 0x1000
>> 9: [160..191]: 3751976..3752007 32 0x1008
>> 10: [192..223]: 3751984..3752015 32 0x1008
>> 11: [224..255]: 3751992..3752023 32 0x1008
>> 12: [256..287]: 3752000..3752031 32 0x1008
>> 13: [288..319]: 3752008..3752039 32 0x1008
>>
>> I don't see any obvious difference, except w/ current patch, last
>> FIEMAP_EXTENT_LAST is missing.
>>
>> Sorry, I didn't get the point of this patch, could you please explain
>> more details for that problem this patch tries to fix and show the
>> difference before/after the patch in commit message?
>>
>> Thanks,
>>
>>>
>>> Flags
>>> 0x1000 => FIEMAP_EXTENT_MERGED
>>> 0x0008 => FIEMAP_EXTENT_ENCODED
>>>
>>> Signed-off-by: Daeho Jeong <daehojeong@...gle.com>
>>>
>>> ---
>>> v2: changed the print format
>>> ---
>>> fs/f2fs/data.c | 76 ++++++++++++++++++++++++++++----------------------
>>> 1 file changed, 42 insertions(+), 34 deletions(-)
>>>
>>> diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
>>> index 3a01a1b50104..058dc751e3a6 100644
>>> --- a/fs/f2fs/data.c
>>> +++ b/fs/f2fs/data.c
>>> @@ -1843,8 +1843,9 @@ int f2fs_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
>>> u64 logical = 0, phys = 0, size = 0;
>>> u32 flags = 0;
>>> int ret = 0;
>>> - bool compr_cluster = false;
>>> + bool compr_cluster = false, compr_appended;
>>> unsigned int cluster_size = F2FS_I(inode)->i_cluster_size;
>>> + unsigned int count_in_cluster;
>>> loff_t maxbytes;
>>>
>>> if (fieinfo->fi_flags & FIEMAP_FLAG_CACHE) {
>>> @@ -1892,8 +1893,10 @@ int f2fs_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
>>> map.m_next_pgofs = &next_pgofs;
>>> map.m_seg_type = NO_CHECK_TYPE;
>>>
>>> - if (compr_cluster)
>>> - map.m_len = cluster_size - 1;
>>> + if (compr_cluster) {
>>> + map.m_lblk += 1;
>>> + map.m_len = cluster_size - count_in_cluster;
>>> + }
>>>
>>> ret = f2fs_map_blocks(inode, &map, 0, F2FS_GET_BLOCK_FIEMAP);
>>> if (ret)
>>> @@ -1903,11 +1906,23 @@ int f2fs_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
>>> if (!(map.m_flags & F2FS_MAP_FLAGS)) {
>>> start_blk = next_pgofs;
>>>
>>> - if (blks_to_bytes(inode, start_blk) < blks_to_bytes(inode,
>>> + if (blks_to_bytes(inode, start_blk) >= blks_to_bytes(inode,
>>> max_inode_blocks(inode)))
>>> + flags |= FIEMAP_EXTENT_LAST;
>>> + else if (!compr_cluster)
>>> goto prep_next;
>>> + }
>>> +
>>> + compr_appended = false;
>>> + /* In a case of compressed cluster, append this to the last extent */
>>> + if (compr_cluster && ((map.m_flags & F2FS_MAP_UNWRITTEN) ||
>>> + !(map.m_flags & F2FS_MAP_FLAGS))) {
>>> + unsigned int appended_blks = cluster_size - count_in_cluster + 1;
>>>
>>> - flags |= FIEMAP_EXTENT_LAST;
>>> + size += blks_to_bytes(inode, appended_blks);
>>> + if (map.m_flags & F2FS_MAP_UNWRITTEN)
>>> + start_blk += appended_blks;
>>> + compr_appended = true;
>>> }
>>>
>>> if (size) {
>>> @@ -1926,38 +1941,31 @@ int f2fs_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
>>> if (start_blk > last_blk)
>>> goto out;
>>>
>>> - if (compr_cluster) {
>>> - compr_cluster = false;
>>> -
>>> -
>>> - logical = blks_to_bytes(inode, start_blk - 1);
>>> - phys = blks_to_bytes(inode, map.m_pblk);
>>> - size = blks_to_bytes(inode, cluster_size);
>>> -
>>> - flags |= FIEMAP_EXTENT_ENCODED;
>>> -
>>> - start_blk += cluster_size - 1;
>>> -
>>> - if (start_blk > last_blk)
>>> - goto out;
>>> -
>>> - goto prep_next;
>>> - }
>>> -
>>> if (map.m_pblk == COMPRESS_ADDR) {
>>> compr_cluster = true;
>>> - start_blk++;
>>> - goto prep_next;
>>> - }
>>> -
>>> - logical = blks_to_bytes(inode, start_blk);
>>> - phys = blks_to_bytes(inode, map.m_pblk);
>>> - size = blks_to_bytes(inode, map.m_len);
>>> - flags = 0;
>>> - if (map.m_flags & F2FS_MAP_UNWRITTEN)
>>> - flags = FIEMAP_EXTENT_UNWRITTEN;
>>> + count_in_cluster = 1;
>>> + } else if (compr_appended) {
>>> + compr_cluster = false;
>>> + } else {
>>> + logical = blks_to_bytes(inode, start_blk);
>>> + phys = __is_valid_data_blkaddr(map.m_pblk) ?
>>> + blks_to_bytes(inode, map.m_pblk) : 0;
>>> + size = blks_to_bytes(inode, map.m_len);
>>> + flags = 0;
>>> +
>>> + if (compr_cluster) {
>>> + flags = FIEMAP_EXTENT_ENCODED;
>>> + count_in_cluster += map.m_len;
>>> + if (count_in_cluster == cluster_size) {
>>> + compr_cluster = false;
>>> + size += blks_to_bytes(inode, 1);
>>> + }
>>> + } else if (map.m_flags & F2FS_MAP_UNWRITTEN) {
>>> + flags = FIEMAP_EXTENT_UNWRITTEN;
>>> + }
>>>
>>> - start_blk += bytes_to_blks(inode, size);
>>> + start_blk += bytes_to_blks(inode, size);
>>> + }
>>>
>>> prep_next:
>>> cond_resched();
>>>
>
> Oh, I am sorry for too concrete exlpanation.
> I am trying to fix this issue. Let's assume 4 block cluster, which has
> been compressed with 3 blocks whose address is 0x1000, 0x5000 and
> 0x9000.
> This cluster is discontinous cluster. In this condition, the previous
> version just returns one extent starting from 0x1000 and we are
> missing the information related to 0x5000 and 0x9000.
> The current version will return 3 extents like below.
> Logical Physical Len
> 0x0 0x1000. 0x1000
> 0x1. 0x5000. 0x1000
> 0x2. 0x9000. 0x2000
Ah, thanks for detailed explanation, I misread your commit message
previously... :(
>
> Thank you for letting me know a bug. I will fix it.
So, let me review the patch after the fix. :)
Thanks,
>
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