kernel/linux.git/fs/erofs, branch v7.2-rc1

erofs: handle 48-bit blocks_hi for compressed inodes

2026-06-22T10:50:36+00:00

Combine i_nb.blocks_hi with i_u.blocks_lo when computing inode->i_blocks for compressed inodes, mirroring the startblk_hi handling for unencoded inodes a few lines above. Also evaluate the shift in u64 to avoid truncation. Fixes: efb2aef569b3 ("erofs: add encoded extent on-disk definition") Fixes: 1d191b4ca51d ("erofs: implement encoded extent metadata") Reviewed-by: Gao Xiang Signed-off-by: Zhan Xusheng Signed-off-by: Gao Xiang

erofs: remove fscache backend entirely

2026-06-22T03:00:06+00:00

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: simplify RCU read critical sections

2026-06-21T22:49:14+00:00

- use scoped_guard() for RCU read critical section in z_erofs_decompress_kickoff(); - simplify the RCU critical section loop in z_erofs_pcluster_begin(). Signed-off-by: Gao Xiang

erofs: add sparse support to pcluster layout

2026-06-21T22:48:59+00:00

Although zeros can be compressed transparently on EROFS using fixed-size output compression so that it is never prioritized in the Android use cases, indicating entire pclusters as holes is still useful to preserve holes in the sparse datasets; otherwise overlayfs will allocate more space when copying up, and SEEK_HOLE won't report any hole. This patch introduces two ways to mark a pcluster as a hole: - A new Z_EROFS_LI_HOLE compatible flag (bit 14) in the HEAD lcluster advise field for non-compact (full) indexes; - A 0-block CBLKCNT value on the first NONHEAD lcluster. The hole tag is preferred for maximum compatibility since pre-existing kernels that do not understand Z_EROFS_LI_HOLE will decompress at the stored blkaddr (the same blkaddr will be shared among all sparse pclusters). Only the 0-block CBLKCNT approach also works for compact indexes, but it is limited to big pclusters and new kernels. Signed-off-by: Gao Xiang

erofs: introduce erofs_map_chunks()

2026-06-17T04:01:45+00:00

Try to map more chunks in the same metadata on-disk block for more efficient IO performance. Signed-off-by: Gao Xiang

erofs: call erofs_exit_ishare() before rcu_barrier()

2026-06-17T04:01:34+00:00

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: clean up erofs_ishare_fill_inode()

2026-06-17T03:19:51+00:00

- Use the shorthand `si` to replace the overly long `sharedinode`; - Introduce erofs_warn() and get rid of barely-used _erofs_printk(); - Get rid of the variable `hash`; - Simplify error paths. Reviewed-by: Hongbo Li Reviewed-by: Chao Yu Signed-off-by: Gao Xiang

erofs: fix EFSCORRUPTED on multi-algorithm images in z_erofs_map_sanity_check()

2026-06-01T17:52:58+00:00

Commit a5242d37c83a ("erofs: error out obviously illegal extents in advance") changed the per-extent algorithm presence check from "is the bit set" to "is the only bit set": - !(sbi->available_compr_algs & (1 << map->m_algorithmformat)) + (sbi->available_compr_algs ^ BIT(map->m_algorithmformat)) `available_compr_algs` is a bitmap of every compression algorithm available in the image (z_erofs_parse_cfgs() iterates it with for_each_set_bit()), so an image that enables more than one algorithm has multiple bits set. XOR is zero only when the bitmap is exactly BIT(map->m_algorithmformat); for any image with two or more algorithms the test is non-zero for every extent and the read fails with -EFSCORRUPTED ("inconsistent algorithmtype %u"). Reproducer (mkfs.erofs from erofs-utils 1.7.1): $ mkdir src $ yes A | head -c 100K > src/a $ head -c 64K /dev/zero > src/b $ mkfs.erofs -zlz4:deflate multi.erofs src $ mount -t erofs -o loop multi.erofs /mnt $ cat /mnt/a >/dev/null cat: /mnt/a: Structure needs cleaning $ dmesg | tail erofs (device loop0): inconsistent algorithmtype 0 for nid 46 erofs (device loop0): read error -117 @ 0 of nid 46 The erofs on-disk format (Z_EROFS_COMPRESSION_MAX = 4 with LZ4, LZMA, DEFLATE, ZSTD) and the kernel parser explicitly support multi-algorithm images, and erofs-utils 1.7.1 generates them via the "-z X:Y" syntax. Restore the original per-bit presence check. Fixes: a5242d37c83a ("erofs: error out obviously illegal extents in advance") Signed-off-by: Zhan Xusheng Reviewed-by: Gao Xiang Signed-off-by: Gao Xiang

erofs: fix use-after-free on sbi->sync_decompress

2026-05-29T04:32:56+00:00

z_erofs_decompress_kickoff() can race with filesystem unmount, causing a use-after-free on sbi->sync_decompress. When I/O completes, z_erofs_endio() calls z_erofs_decompress_kickoff() to queue z_erofs_decompressqueue_work() asynchronously. Then, after all folios are unlocked, unmount workflow can proceed and sbi will be freed before accessing to sbi->sync_decompress. Thread (unmount) I/O completion kworker queue_work z_erofs_decompressqueue_work (all folios are unlocked) cleanup_mnt .. erofs_kill_sb erofs_sb_free kfree(sbi) access sbi->sync_decompress // UAF!! Fixes: 40452ffca3c1 ("erofs: add sysfs node to control sync decompression strategy") Reported-by: syzbot+52bae5c495dbe261a0bc@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=52bae5c495dbe261a0bc Reviewed-by: Chao Yu Reviewed-by: Jianan Huang Signed-off-by: Gao Xiang

erofs: fix metabuf leak in inode xattr initialization

2026-05-20T06:53:14+00:00

commit bb88e8da0025 ("erofs: use meta buffers for xattr operations") converted xattr operations to use on-stack erofs_buf instances. erofs_init_inode_xattrs() uses such a metabuf while reading the inline xattr header and shared xattr id array. Some error paths after erofs_read_metabuf() leave through out_unlock without dropping the metabuf, so the folio reference can leak. Consolidate the cleanup at out_unlock. erofs_put_metabuf() is a no-op if no folio has been acquired, and this keeps all paths after taking EROFS_I_BL_XATTR_BIT covered by a single cleanup site. Fixes: bb88e8da0025 ("erofs: use meta buffers for xattr operations") Signed-off-by: Jia Zhu Reviewed-by: Gao Xiang Fixes: bb88e8da0025 ("erofs: use meta buffers for xattr operations") Signed-off-by: Gao Xiang