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| author | Jingbo Xu <jefflexu@linux.alibaba.com> | 2022-11-04 13:40:28 +0800 |
|---|---|---|
| committer | Gao Xiang <hsiangkao@linux.alibaba.com> | 2022-11-08 14:46:30 +0800 |
| commit | e6d9f9ba111b56154f1b1120252aff269cebd49c (patch) | |
| tree | cb957acb4f9ff55a3caea2ab1bc1e79e5c90555c /fs/erofs/fscache.c | |
| parent | 75e43355cbe4d5948a79bd592f2ffecb9f75f75d (diff) | |
| download | linux-e6d9f9ba111b56154f1b1120252aff269cebd49c.tar.gz linux-e6d9f9ba111b56154f1b1120252aff269cebd49c.tar.bz2 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.c | 7 |
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, |