kernel/linux.git/fs/erofs/super.c, branch linux-7.1.y

erofs: handle 48-bit blocks/uniaddr for extra devices

2026-04-07T03:46:31+00:00

erofs_init_device() only reads blocks_lo and uniaddr_lo from the on-disk device slot, ignoring blocks_hi and uniaddr_hi that were introduced alongside the 48-bit block addressing feature. For the primary device (dif0), erofs_read_superblock() already handles this correctly by combining blocks_lo with blocks_hi when 48-bit layout is enabled. But the same logic was not applied to extra devices. With a 48-bit EROFS image using extra devices whose uniaddr or blocks exceed 32-bit range, the truncated values cause erofs_map_dev() to compute wrong physical addresses, leading to silent data corruption. Fix this by reading blocks_hi and uniaddr_hi in erofs_init_device() when 48-bit layout is enabled, consistent with the primary device handling. Also fix the erofs_deviceslot on-disk definition where blocks_hi was incorrectly declared as __le32 instead of __le16. Fixes: 61ba89b57905 ("erofs: add 48-bit block addressing on-disk support") Suggested-by: Gao Xiang Signed-off-by: Zhan Xusheng Reviewed-by: Gao Xiang Signed-off-by: Gao Xiang

erofs: remove more unnecessary #ifdefs

2026-02-24T10:36:52+00:00

Many #ifdefs can be replaced with IS_ENABLED() to improve code readability. No functional changes. Signed-off-by: Ferry Meng Reviewed-by: Gao Xiang Signed-off-by: Gao Xiang

Convert 'alloc_obj' family to use the new default GFP_KERNEL argument

2026-02-22T01:09:51+00:00

This was done entirely with mindless brute force, using git grep -l '\

treewide: Replace kmalloc with kmalloc_obj for non-scalar types

2026-02-21T09:02:28+00:00

This is the result of running the Coccinelle script from scripts/coccinelle/api/kmalloc_objs.cocci. The script is designed to avoid scalar types (which need careful case-by-case checking), and instead replace kmalloc-family calls that allocate struct or union object instances: Single allocations: kmalloc(sizeof(TYPE), ...) are replaced with: kmalloc_obj(TYPE, ...) Array allocations: kmalloc_array(COUNT, sizeof(TYPE), ...) are replaced with: kmalloc_objs(TYPE, COUNT, ...) Flex array allocations: kmalloc(struct_size(PTR, FAM, COUNT), ...) are replaced with: kmalloc_flex(*PTR, FAM, COUNT, ...) (where TYPE may also be *VAR) The resulting allocations no longer return "void *", instead returning "TYPE *". Signed-off-by: Kees Cook

erofs: avoid some unnecessary #ifdefs

2026-02-03T03:25:55+00:00

They can either be removed or replaced with IS_ENABLED(). Signed-off-by: Ferry Meng Reviewed-by: Gao Xiang Signed-off-by: Gao Xiang

erofs: separate plain and compressed filesystems formally

2026-02-03T03:05:57+00:00

The EROFS on-disk format uses a tiny, plain metadata design that prioritizes performance and minimizes complex inconsistencies against common writable disk filesystems (almost all serious metadata inconsistency cannot happen in well-designed immutable filesystems like EROFS). EROFS deliberately avoids artificial design flaws to eliminate serious security risks from untrusted remote sources by design, although human-made implementation bugs can still happen sometimes. Currently, there is no strict check to prevent compressed inodes, especially LZ4-compressed inodes, from being read in plain filesystems. Starting with erofs-utils 1.0 and Linux 5.3, LZ4_0PADDING sb feature is automatically enabled for LZ4-compressed EROFS images to support in-place decompression. Furthermore, since Linux 5.4 LTS is no longer supported, we no longer need to handle ancient LZ4-compressed EROFS images generated by erofs-utils prior to 1.0. To formally distinguish different filesystem types for improved security: - Use the presence of LZ4_0PADDING or a non-zero `dsb->u1.lz4_max_distance` as a marker for compressed filesystems containing LZ4-compressed inodes only; - For other algorithms, use `dsb->u1.available_compr_algs` bitmap. Note: LZ4_0PADDING has been supported since Linux 5.4 (the first formal kernel version), so exposing it via sysfs is no longer necessary and is now deprecated (but remain it for five more years until 2031): `dsb->u1` has been strictly non-zero for all EROFS images containing compressed inodes starting with erofs-utils v1.3 and it is actually a much better marker for compressed filesystems. Signed-off-by: Gao Xiang

erofs: introduce the page cache share feature

2026-01-23T12:02:09+00:00

Currently, reading files with different paths (or names) but the same content will consume multiple copies of the page cache, even if the content of these page caches is the same. For example, reading identical files (e.g., *.so files) from two different minor versions of container images will cost multiple copies of the same page cache, since different containers have different mount points. Therefore, sharing the page cache for files with the same content can save memory. This introduces the page cache share feature in erofs. It allocate a shared inode and use its page cache as shared. Reads for files with identical content will ultimately be routed to the page cache of the shared inode. In this way, a single page cache satisfies multiple read requests for different files with the same contents. We introduce new mount option `inode_share` to enable the page sharing mode during mounting. This option is used in conjunction with `domain_id` to share the page cache within the same trusted domain. Signed-off-by: Hongzhen Luo Signed-off-by: Hongbo Li Reviewed-by: Gao Xiang Signed-off-by: Gao Xiang

erofs: using domain_id in the safer way

2026-01-23T12:02:09+00:00

Either the existing fscache usecase or the upcoming page cache sharing case, the `domain_id` should be protected as sensitive information, so we use the safer helpers to allocate, free and display domain_id. Signed-off-by: Hongbo Li Reviewed-by: Gao Xiang Signed-off-by: Gao Xiang

erofs: support user-defined fingerprint name

2026-01-23T12:01:13+00:00

When creating the EROFS image, users can specify the fingerprint name. This is to prepare for the upcoming inode page cache share. Signed-off-by: Hongzhen Luo Signed-off-by: Hongbo Li Reviewed-by: Gao Xiang Signed-off-by: Gao Xiang

erofs: decouple `struct erofs_anon_fs_type`

2026-01-23T12:01:13+00:00

- Move the `struct erofs_anon_fs_type` to super.c and expose it in preparation for the upcoming page cache share feature; - Remove the `.owner` field, as they are all internal mounts and fully managed by EROFS. Retaining `.owner` would unnecessarily increment module reference counts, preventing the EROFS kernel module from being unloaded. Signed-off-by: Gao Xiang