linux.git/fs/erofs/super.c, branch master

erofs: hide "cache_strategy=" for plain filesystems

2026-07-13T08:41:42Z

"cache_strategy=" is meaningless and confusing on unencoded EROFS filesystems; gate it on compressed images only since it's now possible after commit 7cef3c834194 ("erofs: separate plain and compressed filesystems formally"). Signed-off-by: Gao Xiang

erofs: use more informative s_id for file-backed mounts

2026-06-30T05:42:53Z

For file-backed mounts, set sb->s_id to the MAJOR:MINOR of sb->s_dev (which fstat() will return) so that kernel messages and the sysfs name are more informative rather than just "erofs: (device erofs): ...". Reviewed-by: Hongbo Li Signed-off-by: Gao Xiang

erofs: remove fscache backend entirely

2026-06-22T03:00:06Z

EROFS over fscache was introduced to provide image lazy pulling functionality. After the feature landed, the fscache subsystem made netfs a new hard dependency, which is unexpected for a local filesystem and has an kernel-defined caching hierarchy which could be inflexible compared to the fanotify pre-content hooks. Therefore, this feature has been deprecated for almost two years. As EROFS file-backed mounts and fanotify pre-content hooks both upstream for a while and already providing equivalent functionality (erofs-utils has supported fanotify pre-content hooks), let's remove the fscache backend now. The main application of this feature is Nydus [1], and they plan to move to use fanotify pre-content hooks in the near future too. I hope this patch can be merged into Linux 7.2, which is also motivated by newly found implementation issues [2][3] that are not worth investigating given the deprecation and limited development resources. The associated fscache/cachefiles cleanup patch will follow separately through the vfs tree (netfs) later: it seems fine since the codebase is isolated by CONFIG_CACHEFILES_ONDEMAND. [1] https://github.com/dragonflyoss/nydus/blob/v2.1.0/docs/nydus-fscache.md [2] https://github.com/dragonflyoss/nydus/pull/1824 [3] https://lore.kernel.org/r/20260619135800.1594811-1-michael.bommarito@gmail.com Acked-by: Jingbo Xu Signed-off-by: Gao Xiang

erofs: call erofs_exit_ishare() before rcu_barrier()

2026-06-17T04:01:34Z

Ensure all inode free callbacks have completed before destroying the inode slab cache. Fixes: 5ef3208e3be5 ("erofs: introduce the page cache share feature") Reviewed-by: Hongbo Li Signed-off-by: Gao Xiang

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

2026-04-07T03:46:31Z

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

2026-02-24T10:36:52Z

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

2026-02-22T01:09:51Z

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

treewide: Replace kmalloc with kmalloc_obj for non-scalar types

2026-02-21T09:02:28Z

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

2026-02-03T03:25:55Z

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

2026-02-03T03:05:57Z

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