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| author | Gao Xiang <hsiangkao@linux.alibaba.com> | 2022-02-04 03:02:03 +0800 |
|---|---|---|
| committer | Gao Xiang <hsiangkao@linux.alibaba.com> | 2022-02-04 12:37:12 +0800 |
| commit | 24331050a3e6afcd4451409831dd9ae8085a42f6 (patch) | |
| tree | df3e493ae7115f10582f4bfa903da01e32f7f81c /fs/erofs | |
| parent | 7865827c432bf9885ee26e5767697c3d9e21a82c (diff) | |
| download | linux-24331050a3e6afcd4451409831dd9ae8085a42f6.tar.bz2 | |
erofs: fix small compressed files inlining
Prior to ztailpacking feature, it's enough that each lcluster has
two pclusters at most, and the last pcluster should be turned into
an uncompressed pcluster when necessary. For example,
_________________________________________________
|_ pcluster n-2 _|_ pcluster n-1 _|____ EOFed ____|
which should be converted into:
_________________________________________________
|_ pcluster n-2 _|_ pcluster n-1 (uncompressed)' _|
That is fine since either pcluster n-1 or (uncompressed)' takes one
physical block.
However, after ztailpacking was supported, the game is changed since
the last pcluster can be inlined now. And such case above is quite
common for inlining small files. Therefore, in order to inline more
effectively, special EOF lclusters are now supported which can have
three parts at most, as illustrated below:
_________________________________________________
|_ pcluster n-2 _|_ pcluster n-1 _|____ EOFed ____|
^ i_size
Actually similar code exists in Yue Hu's original patchset [1], but I
removed this part on purpose. After evaluating more real cases with
small files, I've changed my mind.
[1] https://lore.kernel.org/r/20211215094449.15162-1-huyue2@yulong.com
Link: https://lore.kernel.org/r/20220203190203.30794-1-xiang@kernel.org
Fixes: ab92184ff8f1 ("erofs: add on-disk compressed tail-packing inline support")
Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Diffstat (limited to 'fs/erofs')
| -rw-r--r-- | fs/erofs/zmap.c | 7 |
1 files changed, 7 insertions, 0 deletions
diff --git a/fs/erofs/zmap.c b/fs/erofs/zmap.c index 18d7fd1a5064..361b1d6e4bf9 100644 --- a/fs/erofs/zmap.c +++ b/fs/erofs/zmap.c @@ -630,6 +630,13 @@ static int z_erofs_do_map_blocks(struct inode *inode, if (endoff >= m.clusterofs) { m.headtype = m.type; map->m_la = (m.lcn << lclusterbits) | m.clusterofs; + /* + * For ztailpacking files, in order to inline data more + * effectively, special EOF lclusters are now supported + * which can have three parts at most. + */ + if (ztailpacking && end > inode->i_size) + end = inode->i_size; break; } /* m.lcn should be >= 1 if endoff < m.clusterofs */ |