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Date: Tue, 27 Jul 2021 18:19:08 +0800
From: Chao Yu <chao@...nel.org>
To: Daeho Jeong <daeho43@...il.com>, linux-kernel@...r.kernel.org,
linux-f2fs-devel@...ts.sourceforge.net, kernel-team@...roid.com
Cc: Daeho Jeong <daehojeong@...gle.com>,
Eric Biggers <ebiggers@...gle.com>
Subject: Re: [f2fs-dev] [PATCH v4] f2fs: change fiemap way in printing
compression chunk
On 2021/7/26 12:18, 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.
>
> Let's assume 16KB compression cluster.
>
> <before>
> Logical Physical Length Flags
> 0: 0000000000000000 00000002c091f000 0000000000004000 1008
> 1: 0000000000004000 00000002c0920000 0000000000004000 1008
> ...
> 9: 0000000000034000 0000000f8c623000 0000000000004000 1008
> 10: 0000000000038000 000000101a6eb000 0000000000004000 1008
>
> <after>
> 0: 0000000000000000 00000002c091f000 0000000000004000 1008
> 1: 0000000000004000 00000002c0920000 0000000000004000 1008
> ...
> 9: 0000000000034000 0000000f8c623000 0000000000001000 1008
> 10: 0000000000035000 000000101a6ea000 0000000000003000 1008
> 11: 0000000000038000 000000101a6eb000 0000000000002000 1008
> 12: 000000000003a000 00000002c3544000 0000000000002000 1008
>
> Flags
> 0x1000 => FIEMAP_EXTENT_MERGED
> 0x0008 => FIEMAP_EXTENT_ENCODED
>
> Signed-off-by: Daeho Jeong <daehojeong@...gle.com>
> Tested-by: Eric Biggers <ebiggers@...gle.com>
>
> ---
> v4: initialized count_in_cluster
> v3: fix the missing last extent flag issue
> v2: changed the print format
> ---
> fs/f2fs/data.c | 75 ++++++++++++++++++++++++++++----------------------
> 1 file changed, 42 insertions(+), 33 deletions(-)
>
> diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
> index 3a01a1b50104..1a716c3b5457 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 = 0;
> loff_t maxbytes;
>
> if (fieinfo->fi_flags & FIEMAP_FLAG_CACHE) {
> @@ -1892,15 +1893,17 @@ 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)
> goto out;
>
> /* HOLE */
> - if (!(map.m_flags & F2FS_MAP_FLAGS)) {
> + if (!compr_cluster && !(map.m_flags & F2FS_MAP_FLAGS)) {
> start_blk = next_pgofs;
>
> if (blks_to_bytes(inode, start_blk) < blks_to_bytes(inode,
> @@ -1910,6 +1913,14 @@ int f2fs_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
> flags |= FIEMAP_EXTENT_LAST;
> }
>
> + 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))) {
> + compr_appended = true;
> + goto skip_fill;
> + }
> +
> if (size) {
> flags |= FIEMAP_EXTENT_MERGED;
> if (IS_ENCRYPTED(inode))
> @@ -1926,38 +1937,36 @@ 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;
> - }
> -
> +skip_fill:
> if (map.m_pblk == COMPRESS_ADDR) {
Looks good, but one more thing I concern is how about detecting and
returning -EFSCORRUPTED for below corrupted metadata cases:
- [COMPRESS_ADDR, blkaddr, COMPRESS_ADDR, NEW_ADDR]
- [blkaddr, COMPRESS_ADDR, NULL_ADDR, NULL_ADDR]
Thanks,
> 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) {
> + unsigned int appended_blks = cluster_size -
> + count_in_cluster + 1;
> + size += blks_to_bytes(inode, appended_blks);
> + start_blk += appended_blks;
> + 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();
>
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