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| 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 /Documentation/filesystems | |
| parent | 12bf25d1659b1ec55e44fad2485155707062df79 (diff) | |
| download | tip-c36ec00d7f67590cb03e233959cd92fe969753a3.tar.gz | |
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 'Documentation/filesystems')
| -rw-r--r-- | Documentation/filesystems/erofs.rst | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/Documentation/filesystems/erofs.rst b/Documentation/filesystems/erofs.rst index c293f8e37468cd..7ddb235aee9d4e 100644 --- a/Documentation/filesystems/erofs.rst +++ b/Documentation/filesystems/erofs.rst @@ -128,6 +128,7 @@ device=%s Specify a path to an extra device to be used together. fsid=%s Specify a filesystem image ID for Fscache back-end. domain_id=%s Specify a domain ID in fscache mode so that different images with the same blobs under a given domain ID can share storage. +fsoffset=%llu Specify block-aligned filesystem offset for the primary device. =================== ========================================================= Sysfs Entries |