kernel/git/stable/linux.git/fs/romfs, branch master

Merge tag 'vfs-7.3-rc1.super' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs

2026-08-17T20:57:04+00:00

Pull vfs superblock updates from Christian Brauner: - Make it possible to share a block device between multiple filesystems. erofs can mount read-only blob devices shared between many superblocks, but because we only tracked a single superblock a freeze, thaw, removal or sync on such a device was never propagated to all the superblocks using it, and there was no way to find them. Add an efficient table to lookup all superblocks using a given block device. - A bunch of pre-existing fixes fell out of this work: A block-device freeze racing a btrfs device change could leave the whole filesystem stuck frozen. A bdev_freeze() issued by "dmsetup suspend" or an LVM snapshot resolves that holder to freeze the filesystem. and bdev_thaw() resolves it again to thaw. A freeze landing while btrfs is adding, removing or replacing a device freezes the filesystem. The membership change then drops that link. So the matching thaw could no longer find the superblock. Forbid freezing a device for the duration of a membership change, modelled on deny_write_access()/allow_write_access(). * tag 'vfs-7.3-rc1.super' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs: (24 commits) super: fix dying superblock warning messages block: reject block device inodes with i_rdev == 0 in lookup_bdev() selftests/filesystems: add ustat() coverage fs: look up the superblock via the device table in user_get_super() super: make fs_holder_ops private f2fs: open via dedicated fs bdev helpers erofs: open via dedicated fs bdev helpers fs: tolerate per-superblock freeze errors on shared devices fs: look up superblocks via the device table in fs_holder_ops ext4: open via dedicated fs bdev helpers btrfs: open via dedicated fs bdev helpers xfs: port to fs_bdev_file_open_by_path() fs: add dedicated block device open helpers for filesystems fs: maintain a global device-to-superblock table ocfs2: don't reset s_dev on dismount ext4: use anonymous devices for KUnit test superblocks fs, block: move blk_mode_t and fop_flags_t into super: take lock after last reference count super: convert s_count to refcount_t s_passive btrfs: deny freezing devices undergoing a replace ...

romfs: detect hard link cycles

2026-07-31T08:09:06+00:00

romfs_iget() follows on-disk hard link entries until it reaches a non-hard link inode: pos = be32_to_cpu(ri.spec) & ROMFH_MASK; The target position is image-controlled, and the loop does not detect cycles. A crafted romfs image can make the root inode a hard link. The hard link can point back to itself and leave mount(2) spinning in the kernel. Reject excessive hard link indirection with -ELOOP. Normal romfs images do not need long hard link chains. This bounds corrupted-image traversal. Propagate romfs_iget() errors from lookup because hard link traversal can now fail with -ELOOP. Signed-off-by: 이상호 Link: https://patch.msgid.link/20260701220729.822112-1-kudo3228@gmail.com Signed-off-by: Christian Brauner (Amutable)

fs: add dedicated block device open helpers for filesystems

2026-06-29T08:31:52+00:00

Add fs_bdev_file_open_by_{dev,path}() and fs_bdev_file_release(). They open the device with fs_holder_ops and register a claim in the device-to-superblock table. Claims on the same (device, superblock) pair share one entry, so when a filesystem claims a device it already uses (xfs with its log on the data device), no second entry is added and each superblock will be acted on once. The holder argument remains purely the block layer's exclusivity token: a superblock, or a file_system_type for a device shared by several superblocks of that type. The shared case only becomes usable once the fs_holder_ops callbacks resolve superblocks through the table instead of bdev->bd_holder. Convert the main device, setup_bdev_super() and kill_block_super(), over: the open finds the entry registered by sget_fc() and claims it again. cramfs and romfs bypass kill_block_super() so they can handle MTD mounts and release the main device with a plain bdev_fput(), which would leave the claim behind: the (dev, sb) entry would never be unregistered and the passive reference it holds would keep the superblock alive forever. Convert their release paths in the same step. The frozen-device check stays in setup_bdev_super() for the primary device and is added to fs_bdev_register() for new claims, i.e. every additional device a filesystem opens through the helpers. Only a (device, superblock) pair the superblock claimed earlier may be reopened while frozen (xfs with its log on the data device): the freeze already covers that superblock through the existing claim, so nothing escapes it. Without the setup_bdev_super() check a device frozen before the mount even started (dm lock_fs, loop) could be mounted and written to (journal replay) under an active freeze, because the primary open reuses the entry registered by sget_fc() and never takes the new-claim path. Both checks read bd_fsfreeze_count only after the entry is published (by sget_fc() for the primary, by fs_bdev_register() for new claims) and pair with bdev_freeze() incrementing the count before walking the table: either the mount sees the elevated freeze count and fails with EBUSY, or the freeze finds the published entry and converges once SB_BORN is set. Link: https://patch.msgid.link/20260616-work-super-bdev_holder_global-v2-8-7df6b864028e@kernel.org Reviewed-by: Jan Kara Signed-off-by: Christian Brauner (Amutable)

Merge tag 'mm-stable-2026-02-18-19-48' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

2026-02-19T04:50:32+00:00

Pull more MM updates from Andrew Morton: - "mm/vmscan: fix demotion targets checks in reclaim/demotion" fixes a couple of issues in the demotion code - pages were failed demotion and were finding themselves demoted into disallowed nodes (Bing Jiao) - "Remove XA_ZERO from error recovery of dup_mmap()" fixes a rare mapledtree race and performs a number of cleanups (Liam Howlett) - "mm: add bitmap VMA flag helpers and convert all mmap_prepare to use them" implements a lot of cleanups following on from the conversion of the VMA flags into a bitmap (Lorenzo Stoakes) - "support batch checking of references and unmapping for large folios" implements batching to greatly improve the performance of reclaiming clean file-backed large folios (Baolin Wang) - "selftests/mm: add memory failure selftests" does as claimed (Miaohe Lin) * tag 'mm-stable-2026-02-18-19-48' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (36 commits) mm/page_alloc: clear page->private in free_pages_prepare() selftests/mm: add memory failure dirty pagecache test selftests/mm: add memory failure clean pagecache test selftests/mm: add memory failure anonymous page test mm: rmap: support batched unmapping for file large folios arm64: mm: implement the architecture-specific clear_flush_young_ptes() arm64: mm: support batch clearing of the young flag for large folios arm64: mm: factor out the address and ptep alignment into a new helper mm: rmap: support batched checks of the references for large folios tools/testing/vma: add VMA userland tests for VMA flag functions tools/testing/vma: separate out vma_internal.h into logical headers tools/testing/vma: separate VMA userland tests into separate files mm: make vm_area_desc utilise vma_flags_t only mm: update all remaining mmap_prepare users to use vma_flags_t mm: update shmem_[kernel]_file_*() functions to use vma_flags_t mm: update secretmem to use VMA flags on mmap_prepare mm: update hugetlbfs to use VMA flags on mmap_prepare mm: add basic VMA flag operation helper functions tools: bitmap: add missing bitmap_[subset(), andnot()] mm: add mk_vma_flags() bitmap flag macro helper ...

mm: update all remaining mmap_prepare users to use vma_flags_t

2026-02-12T23:42:58+00:00

We will be shortly removing the vm_flags_t field from vm_area_desc so we need to update all mmap_prepare users to only use the dessc->vma_flags field. This patch achieves that and makes all ancillary changes required to make this possible. This lays the groundwork for future work to eliminate the use of vm_flags_t in vm_area_desc altogether and more broadly throughout the kernel. While we're here, we take the opportunity to replace VM_REMAP_FLAGS with VMA_REMAP_FLAGS, the vma_flags_t equivalent. No functional changes intended. Link: https://lkml.kernel.org/r/fb1f55323799f09fe6a36865b31550c9ec67c225.1769097829.git.lorenzo.stoakes@oracle.com Signed-off-by: Lorenzo Stoakes Acked-by: Damien Le Moal [zonefs] Acked-by: "Darrick J. Wong" Acked-by: Pedro Falcato Cc: Baolin Wang Cc: Barry Song Cc: David Hildenbrand Cc: Dev Jain Cc: Jason Gunthorpe Cc: Liam Howlett Cc: Suren Baghdasaryan Cc: Vlastimil Babka Cc: Zi Yan Cc: Jarkko Sakkinen Cc: Yury Norov Cc: Chris Mason Signed-off-by: Andrew Morton

romfs: check sb_set_blocksize() return value

2026-01-13T08:56:58+00:00

romfs_fill_super() ignores the return value of sb_set_blocksize(), which can fail if the requested block size is incompatible with the block device's configuration. This can be triggered by setting a loop device's block size larger than PAGE_SIZE using ioctl(LOOP_SET_BLOCK_SIZE, 32768), then mounting a romfs filesystem on that device. When sb_set_blocksize(sb, ROMBSIZE) is called with ROMBSIZE=4096 but the device has logical_block_size=32768, bdev_validate_blocksize() fails because the requested size is smaller than the device's logical block size. sb_set_blocksize() returns 0 (failure), but romfs ignores this and continues mounting. The superblock's block size remains at the device's logical block size (32768). Later, when sb_bread() attempts I/O with this oversized block size, it triggers a kernel BUG in folio_set_bh(): kernel BUG at fs/buffer.c:1582! BUG_ON(size > PAGE_SIZE); Fix by checking the return value of sb_set_blocksize() and failing the mount with -EINVAL if it returns 0. Reported-by: syzbot+9c4e33e12283d9437c25@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=9c4e33e12283d9437c25 Signed-off-by: Deepanshu Kartikey Link: https://patch.msgid.link/20260113084037.1167887-1-kartikey406@gmail.com Signed-off-by: Christian Brauner

Coccinelle-based conversion to use ->i_state accessors

2025-10-20T18:22:26+00:00

All places were patched by coccinelle with the default expecting that ->i_lock is held, afterwards entries got fixed up by hand to use unlocked variants as needed. The script: @@ expression inode, flags; @@ - inode->i_state & flags + inode_state_read(inode) & flags @@ expression inode, flags; @@ - inode->i_state &= ~flags + inode_state_clear(inode, flags) @@ expression inode, flag1, flag2; @@ - inode->i_state &= ~flag1 & ~flag2 + inode_state_clear(inode, flag1 | flag2) @@ expression inode, flags; @@ - inode->i_state |= flags + inode_state_set(inode, flags) @@ expression inode, flags; @@ - inode->i_state = flags + inode_state_assign(inode, flags) @@ expression inode, flags; @@ - flags = inode->i_state + flags = inode_state_read(inode) @@ expression inode, flags; @@ - READ_ONCE(inode->i_state) & flags + inode_state_read(inode) & flags Signed-off-by: Mateusz Guzik Signed-off-by: Christian Brauner

fs: replace mmap hook with .mmap_prepare for simple mappings

2025-06-19T11:56:59+00:00

Since commit c84bf6dd2b83 ("mm: introduce new .mmap_prepare() file callback"), the f_op->mmap() hook has been deprecated in favour of f_op->mmap_prepare(). This callback is invoked in the mmap() logic far earlier, so error handling can be performed more safely without complicated and bug-prone state unwinding required should an error arise. This hook also avoids passing a pointer to a not-yet-correctly-established VMA avoiding any issues with referencing this data structure. It rather provides a pointer to the new struct vm_area_desc descriptor type which contains all required state and allows easy setting of required parameters without any consideration needing to be paid to locking or reference counts. Note that nested filesystems like overlayfs are compatible with an .mmap_prepare() callback since commit bb666b7c2707 ("mm: add mmap_prepare() compatibility layer for nested file systems"). In this patch we apply this change to file systems with relatively simple mmap() hook logic - exfat, ceph, f2fs, bcachefs, zonefs, btrfs, ocfs2, orangefs, nilfs2, romfs, ramfs and aio. Signed-off-by: Lorenzo Stoakes Link: https://lore.kernel.org/f528ac4f35b9378931bd800920fee53fc0c5c74d.1750099179.git.lorenzo.stoakes@oracle.com Acked-by: Damien Le Moal Reviewed-by: Jan Kara Reviewed-by: Viacheslav Dubeyko Signed-off-by: Christian Brauner

romfs: fix romfs_read_folio()

2024-08-21T20:32:58+00:00

Add the correct offset to folio_zero_tail(). Fixes: d86f2de026c5 ("romfs: Convert romfs_read_folio() to use a folio") Reported-by: Greg Ungerer Link: https://lore.kernel.org/r/Zr0GTnPHfeA0P8nb@casper.infradead.org Signed-off-by: Christian Brauner

romfs: Convert romfs_read_folio() to use a folio

2024-05-31T10:31:42+00:00

Remove the conversion back to struct page and use the folio APIs instead of the page APIs. It's probably more trouble than it's worth to support large folios in romfs, so there are still PAGE_SIZE assumptions in this function. Signed-off-by: Matthew Wilcox (Oracle) Link: https://lore.kernel.org/r/20240530202110.2653630-13-willy@infradead.org Signed-off-by: Christian Brauner