diff options
| author | Sheng Yong <shengyong1@xiaomi.com> | 2025-05-17 17:05:43 +0800 |
|---|---|---|
| committer | Gao Xiang <hsiangkao@linux.alibaba.com> | 2025-05-22 11:57:57 +0800 |
| commit | c36ec00d7f67590cb03e233959cd92fe969753a3 (patch) | |
| tree | 7120c2ae47c17c5027f4a2408e513359f96ca8b0 /fs/erofs/zdata.c | |
| parent | 12bf25d1659b1ec55e44fad2485155707062df79 (diff) | |
erofs: add 'fsoffset' mount option to specify filesystem offset
When attempting to use an archive file, such as APEX on android,
as a file-backed mount source, it fails because EROFS image within
the archive file does not start at offset 0. As a result, a loop
or a dm device is still needed to attach the image file at an
appropriate offset first. Similarly, if an EROFS image within a
block device does not start at offset 0, it cannot be mounted
directly either.
To address this issue, this patch adds a new mount option `fsoffset=x'
to accept a start offset for the primary device. The offset should be
aligned to the block size. EROFS will add this offset before performing
read requests.
Signed-off-by: Sheng Yong <shengyong1@xiaomi.com>
Signed-off-by: Wang Shuai <wangshuai12@xiaomi.com>
Reviewed-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Link: https://lore.kernel.org/r/20250517090544.2687651-1-shengyong1@xiaomi.com
[ Gao Xiang: minor update on documentation and the error message. ]
Reviewed-by: Hongbo Li <lihongbo22@huawei.com>
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Diffstat (limited to 'fs/erofs/zdata.c')
| -rw-r--r-- | fs/erofs/zdata.c | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/fs/erofs/zdata.c b/fs/erofs/zdata.c index b0f93b9be8cc..ab61c84d47cd 100644 --- a/fs/erofs/zdata.c +++ b/fs/erofs/zdata.c @@ -1737,7 +1737,8 @@ drain_io: bio = bio_alloc(mdev.m_bdev, BIO_MAX_VECS, REQ_OP_READ, GFP_NOIO); bio->bi_end_io = z_erofs_endio; - bio->bi_iter.bi_sector = cur >> 9; + bio->bi_iter.bi_sector = + (mdev.m_dif->fsoff + cur) >> 9; bio->bi_private = q[JQ_SUBMIT]; if (readahead) bio->bi_opf |= REQ_RAHEAD; |