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authorJingbo Xu <jefflexu@linux.alibaba.com>2022-11-04 06:40:28 +0100
committerGao Xiang <hsiangkao@linux.alibaba.com>2022-11-08 07:46:30 +0100
commite6d9f9ba111b56154f1b1120252aff269cebd49c (patch)
treecb957acb4f9ff55a3caea2ab1bc1e79e5c90555c /fs/erofs/fscache.c
parenterofs: put metabuf in error path in fscache mode (diff)
downloadlinux-e6d9f9ba111b56154f1b1120252aff269cebd49c.tar.xz
linux-e6d9f9ba111b56154f1b1120252aff269cebd49c.zip
erofs: get correct count for unmapped range in fscache mode
For unmapped range, the returned map.m_llen is zero, and thus the calculated count is unexpected zero. Prior to the refactoring introduced by commit 1ae9470c3e14 ("erofs: clean up .read_folio() and .readahead() in fscache mode"), only the readahead routine suffers from this. With the refactoring of making .read_folio() and .readahead() calling one common routine, both read_folio and readahead have this issue now. Fix this by calculating count separately in unmapped condition. Fixes: c665b394b9e8 ("erofs: implement fscache-based data readahead") Fixes: 1ae9470c3e14 ("erofs: clean up .read_folio() and .readahead() in fscache mode") Signed-off-by: Jingbo Xu <jefflexu@linux.alibaba.com> Reviewed-by: Gao Xiang <hsiangkao@linux.alibaba.com> Reviewed-by: Chao Yu <chao@kernel.org> Link: https://lore.kernel.org/r/20221104054028.52208-3-jefflexu@linux.alibaba.com Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Diffstat (limited to 'fs/erofs/fscache.c')
-rw-r--r--fs/erofs/fscache.c7
1 files changed, 4 insertions, 3 deletions
diff --git a/fs/erofs/fscache.c b/fs/erofs/fscache.c
index 83559008bfa8..260fa4737fc0 100644
--- a/fs/erofs/fscache.c
+++ b/fs/erofs/fscache.c
@@ -296,15 +296,16 @@ static int erofs_fscache_data_read(struct address_space *mapping,
return PAGE_SIZE;
}
- count = min_t(size_t, map.m_llen - (pos - map.m_la), len);
- DBG_BUGON(!count || count % PAGE_SIZE);
-
if (!(map.m_flags & EROFS_MAP_MAPPED)) {
+ count = len;
iov_iter_xarray(&iter, READ, &mapping->i_pages, pos, count);
iov_iter_zero(count, &iter);
return count;
}
+ count = min_t(size_t, map.m_llen - (pos - map.m_la), len);
+ DBG_BUGON(!count || count % PAGE_SIZE);
+
mdev = (struct erofs_map_dev) {
.m_deviceid = map.m_deviceid,
.m_pa = map.m_pa,