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2024-10-30xfs: Reduce unnecessary searches when searching for the best extentsChi Zhiling1-1/+1
Recently, we found that the CPU spent a lot of time in xfs_alloc_ag_vextent_size when the filesystem has millions of fragmented spaces. The reason is that we conducted much extra searching for extents that could not yield a better result, and these searches would cost a lot of time when there were millions of extents to search through. Even if we get the same result length, we don't switch our choice to the new one, so we can definitely terminate the search early. Since the result length cannot exceed the found length, when the found length equals the best result length we already have, we can conclude the search. We did a test in that filesystem: [root@localhost ~]# xfs_db -c freesp /dev/vdb from to extents blocks pct 1 1 215 215 0.01 2 3 994476 1988952 99.99 Before this patch: 0) | xfs_alloc_ag_vextent_size [xfs]() { 0) * 15597.94 us | } After this patch: 0) | xfs_alloc_ag_vextent_size [xfs]() { 0) 19.176 us | } Signed-off-by: Chi Zhiling <chizhiling@kylinos.cn> Reviewed-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: Carlos Maiolino <cem@kernel.org>
2024-10-30xfs: Check for delayed allocations before setting extsizeOjaswin Mujoo3-3/+8
Extsize should only be allowed to be set on files with no data in it. For this, we check if the files have extents but miss to check if delayed extents are present. This patch adds that check. While we are at it, also refactor this check into a helper since it's used in some other places as well like xfs_inactive() or xfs_ioctl_setattr_xflags() **Without the patch (SUCCEEDS)** $ xfs_io -c 'open -f testfile' -c 'pwrite 0 1024' -c 'extsize 65536' wrote 1024/1024 bytes at offset 0 1 KiB, 1 ops; 0.0002 sec (4.628 MiB/sec and 4739.3365 ops/sec) **With the patch (FAILS as expected)** $ xfs_io -c 'open -f testfile' -c 'pwrite 0 1024' -c 'extsize 65536' wrote 1024/1024 bytes at offset 0 1 KiB, 1 ops; 0.0002 sec (4.628 MiB/sec and 4739.3365 ops/sec) xfs_io: FS_IOC_FSSETXATTR testfile: Invalid argument Fixes: e94af02a9cd7 ("[XFS] fix old xfs_setattr mis-merge from irix; mostly harmless esp if not using xfs rt") Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Darrick J. Wong <djwong@kernel.org> Reviewed-by: John Garry <john.g.garry@oracle.com> Signed-off-by: Ojaswin Mujoo <ojaswin@linux.ibm.com> Signed-off-by: Carlos Maiolino <cem@kernel.org>
2024-10-29btrfs: fix use-after-free of block device file in __btrfs_free_extra_devids()Zhihao Cheng1-0/+1
Mounting btrfs from two images (which have the same one fsid and two different dev_uuids) in certain executing order may trigger an UAF for variable 'device->bdev_file' in __btrfs_free_extra_devids(). And following are the details: 1. Attach image_1 to loop0, attach image_2 to loop1, and scan btrfs devices by ioctl(BTRFS_IOC_SCAN_DEV): / btrfs_device_1 → loop0 fs_device \ btrfs_device_2 → loop1 2. mount /dev/loop0 /mnt btrfs_open_devices btrfs_device_1->bdev_file = btrfs_get_bdev_and_sb(loop0) btrfs_device_2->bdev_file = btrfs_get_bdev_and_sb(loop1) btrfs_fill_super open_ctree fail: btrfs_close_devices // -ENOMEM btrfs_close_bdev(btrfs_device_1) fput(btrfs_device_1->bdev_file) // btrfs_device_1->bdev_file is freed btrfs_close_bdev(btrfs_device_2) fput(btrfs_device_2->bdev_file) 3. mount /dev/loop1 /mnt btrfs_open_devices btrfs_get_bdev_and_sb(&bdev_file) // EIO, btrfs_device_1->bdev_file is not assigned, // which points to a freed memory area btrfs_device_2->bdev_file = btrfs_get_bdev_and_sb(loop1) btrfs_fill_super open_ctree btrfs_free_extra_devids if (btrfs_device_1->bdev_file) fput(btrfs_device_1->bdev_file) // UAF ! Fix it by setting 'device->bdev_file' as 'NULL' after closing the btrfs_device in btrfs_close_one_device(). Fixes: 142388194191 ("btrfs: do not background blkdev_put()") CC: stable@vger.kernel.org # 4.19+ Link: https://bugzilla.kernel.org/show_bug.cgi?id=219408 Signed-off-by: Zhihao Cheng <chengzhihao1@huawei.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2024-10-29NFSD: Initialize struct nfsd4_copy earlierChuck Lever1-2/+2
Ensure the refcount and async_copies fields are initialized early. cleanup_async_copy() will reference these fields if an error occurs in nfsd4_copy(). If they are not correctly initialized, at the very least, a refcount underflow occurs. Reported-by: Olga Kornievskaia <okorniev@redhat.com> Fixes: aadc3bbea163 ("NFSD: Limit the number of concurrent async COPY operations") Reviewed-by: Jeff Layton <jlayton@kernel.org> Tested-by: Olga Kornievskaia <okorniev@redhat.com> Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2024-10-29bcachefs: Fix NULL ptr dereference in btree_node_iter_and_journal_peekPiotr Zalewski1-0/+13
Add NULL check for key returned from bch2_btree_and_journal_iter_peek in btree_node_iter_and_journal_peek to avoid NULL ptr dereference in bch2_bkey_buf_reassemble. When key returned from bch2_btree_and_journal_iter_peek is NULL it means that btree topology needs repair. Print topology error message with position at which node wasn't found, its parent node information and btree_id with level. Return error code returned by bch2_topology_error to ensure that topology error is handled properly by recovery. Reported-by: syzbot+005ef9aa519f30d97657@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=005ef9aa519f30d97657 Fixes: 5222a4607cd8 ("bcachefs: BTREE_ITER_WITH_JOURNAL") Suggested-by: Alan Huang <mmpgouride@gmail.com> Suggested-by: Kent Overstreet <kent.overstreet@linux.dev> Signed-off-by: Piotr Zalewski <pZ010001011111@proton.me> Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
2024-10-29bcachefs: fix possible null-ptr-deref in __bch2_ec_stripe_head_get()Gaosheng Cui2-0/+5
The function ec_new_stripe_head_alloc() returns nullptr if kzalloc() fails. It is crucial to verify its return value before dereferencing it to avoid a potential nullptr dereference. Fixes: 035d72f72c91 ("bcachefs: bch2_ec_stripe_head_get() now checks for change in rw devices") Signed-off-by: Gaosheng Cui <cuigaosheng1@huawei.com> Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
2024-10-29bcachefs: Fix deadlock on -ENOSPC w.r.t. partial open bucketsKent Overstreet2-1/+16
Open buckets on the partial list should not count as allocated when we're trying to allocate from the partial list. Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
2024-10-29bcachefs: Don't filter partial list buckets in open_buckets_to_text()Kent Overstreet1-2/+1
these are an important source of stranded buckets we need to be able to watch Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
2024-10-29bcachefs: Don't keep tons of cached pointers aroundKent Overstreet5-28/+89
We had a bug report where the data update path was creating an extent that failed to validate because it had too many pointers; almost all of them were cached. To fix this, we have: - want_cached_ptr(), a new helper that checks if we even want a cached pointer (is on appropriate target, device is readable). - bch2_extent_set_ptr_cached() now only sets a pointer cached if we want it. - bch2_extent_normalize_by_opts() now ensures that we only have a single cached pointer that we want. While working on this, it was noticed that this doesn't work well with reflinked data and per-file options. Another patch series is coming that plumbs through additional io path options through bch_extent_rebalance, with improved option handling. Reported-by: Reed Riley <reed@riley.engineer> Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
2024-10-29bcachefs: init freespace inited bits to 0 in bch2_fs_initializePiotr Zalewski1-0/+9
Initialize freespace_initialized bits to 0 in member's flags and update member's cached version for each device in bch2_fs_initialize. It's possible for the bits to be set to 1 before fs is initialized and if call to bch2_trans_mark_dev_sbs (just before bch2_fs_freespace_init) fails bits remain to be 1 which can later indirectly trigger BUG condition in bch2_bucket_alloc_freelist during shutdown. Reported-by: syzbot+2b6a17991a6af64f9489@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=2b6a17991a6af64f9489 Fixes: bbe682c76789 ("bcachefs: Ensure devices are always correctly initialized") Suggested-by: Kent Overstreet <kent.overstreet@linux.dev> Signed-off-by: Piotr Zalewski <pZ010001011111@proton.me> Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
2024-10-29bcachefs: Fix unhandled transaction restart in fallocateKent Overstreet1-4/+13
This used to not matter, but now we're being more strict. Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
2024-10-28nilfs2: fix kernel bug due to missing clearing of checked flagRyusuke Konishi1-0/+1
Syzbot reported that in directory operations after nilfs2 detects filesystem corruption and degrades to read-only, __block_write_begin_int(), which is called to prepare block writes, may fail the BUG_ON check for accesses exceeding the folio/page size, triggering a kernel bug. This was found to be because the "checked" flag of a page/folio was not cleared when it was discarded by nilfs2's own routine, which causes the sanity check of directory entries to be skipped when the directory page/folio is reloaded. So, fix that. This was necessary when the use of nilfs2's own page discard routine was applied to more than just metadata files. Link: https://lkml.kernel.org/r/20241017193359.5051-1-konishi.ryusuke@gmail.com Fixes: 8c26c4e2694a ("nilfs2: fix issue with flush kernel thread after remount in RO mode because of driver's internal error or metadata corruption") Signed-off-by: Ryusuke Konishi <konishi.ryusuke@gmail.com> Reported-by: syzbot+d6ca2daf692c7a82f959@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=d6ca2daf692c7a82f959 Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-10-28ocfs2: pass u64 to ocfs2_truncate_inline maybe overflowEdward Adam Davis1-0/+8
Syzbot reported a kernel BUG in ocfs2_truncate_inline. There are two reasons for this: first, the parameter value passed is greater than ocfs2_max_inline_data_with_xattr, second, the start and end parameters of ocfs2_truncate_inline are "unsigned int". So, we need to add a sanity check for byte_start and byte_len right before ocfs2_truncate_inline() in ocfs2_remove_inode_range(), if they are greater than ocfs2_max_inline_data_with_xattr return -EINVAL. Link: https://lkml.kernel.org/r/tencent_D48DB5122ADDAEDDD11918CFB68D93258C07@qq.com Fixes: 1afc32b95233 ("ocfs2: Write support for inline data") Signed-off-by: Edward Adam Davis <eadavis@qq.com> Reported-by: syzbot+81092778aac03460d6b7@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=81092778aac03460d6b7 Reviewed-by: Joseph Qi <joseph.qi@linux.alibaba.com> Cc: Joel Becker <jlbec@evilplan.org> Cc: Joseph Qi <joseph.qi@linux.alibaba.com> Cc: Mark Fasheh <mark@fasheh.com> Cc: Junxiao Bi <junxiao.bi@oracle.com> Cc: Changwei Ge <gechangwei@live.cn> Cc: Gang He <ghe@suse.com> Cc: Jun Piao <piaojun@huawei.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-10-28fork: do not invoke uffd on fork if error occursLorenzo Stoakes1-0/+28
Patch series "fork: do not expose incomplete mm on fork". During fork we may place the virtual memory address space into an inconsistent state before the fork operation is complete. In addition, we may encounter an error during the fork operation that indicates that the virtual memory address space is invalidated. As a result, we should not be exposing it in any way to external machinery that might interact with the mm or VMAs, machinery that is not designed to deal with incomplete state. We specifically update the fork logic to defer khugepaged and ksm to the end of the operation and only to be invoked if no error arose, and disallow uffd from observing fork events should an error have occurred. This patch (of 2): Currently on fork we expose the virtual address space of a process to userland unconditionally if uffd is registered in VMAs, regardless of whether an error arose in the fork. This is performed in dup_userfaultfd_complete() which is invoked unconditionally, and performs two duties - invoking registered handlers for the UFFD_EVENT_FORK event via dup_fctx(), and clearing down userfaultfd_fork_ctx objects established in dup_userfaultfd(). This is problematic, because the virtual address space may not yet be correctly initialised if an error arose. The change in commit d24062914837 ("fork: use __mt_dup() to duplicate maple tree in dup_mmap()") makes this more pertinent as we may be in a state where entries in the maple tree are not yet consistent. We address this by, on fork error, ensuring that we roll back state that we would otherwise expect to clean up through the event being handled by userland and perform the memory freeing duty otherwise performed by dup_userfaultfd_complete(). We do this by implementing a new function, dup_userfaultfd_fail(), which performs the same loop, only decrementing reference counts. Note that we perform mmgrab() on the parent and child mm's, however userfaultfd_ctx_put() will mmdrop() this once the reference count drops to zero, so we will avoid memory leaks correctly here. Link: https://lkml.kernel.org/r/cover.1729014377.git.lorenzo.stoakes@oracle.com Link: https://lkml.kernel.org/r/d3691d58bb58712b6fb3df2be441d175bd3cdf07.1729014377.git.lorenzo.stoakes@oracle.com Fixes: d24062914837 ("fork: use __mt_dup() to duplicate maple tree in dup_mmap()") Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Reported-by: Jann Horn <jannh@google.com> Reviewed-by: Jann Horn <jannh@google.com> Reviewed-by: Liam R. Howlett <Liam.Howlett@Oracle.com> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Christian Brauner <brauner@kernel.org> Cc: Jan Kara <jack@suse.cz> Cc: Linus Torvalds <torvalds@linuxfoundation.org> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-10-28autofs: fix thinko in validate_dev_ioctl()Ian Kent1-3/+2
I was so sure the per-dentry expire timeout patch worked ok but my testing was flawed. In validate_dev_ioctl() the check for ioctl AUTOFS_DEV_IOCTL_TIMEOUT_CMD should use the ioctl number not the passed in ioctl command. Fixes: 433f9d76a010 ("autofs: add per dentry expire timeout") Cc: <stable@vger.kernel.org> # mainline only Signed-off-by: Ian Kent <raven@themaw.net> Link: https://lore.kernel.org/r/20241027224732.5507-1-raven@themaw.net Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-10-28ksmbd: Fix the missing xa_store error checkJinjie Ruan1-4/+7
xa_store() can fail, it return xa_err(-EINVAL) if the entry cannot be stored in an XArray, or xa_err(-ENOMEM) if memory allocation failed, so check error for xa_store() to fix it. Cc: stable@vger.kernel.org Fixes: b685757c7b08 ("ksmbd: Implements sess->rpc_handle_list as xarray") Signed-off-by: Jinjie Ruan <ruanjinjie@huawei.com> Acked-by: Namjae Jeon <linkinjeon@kernel.org> Signed-off-by: Steve French <stfrench@microsoft.com>
2024-10-27Merge tag 'xfs-6.12-fixes-5' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linuxLinus Torvalds7-78/+122
Pull xfs fixes from Carlos Maiolino: - Fix recovery of allocator ops after a growfs - Do not fail repairs on metadata files with no attr fork * tag 'xfs-6.12-fixes-5' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux: xfs: update the pag for the last AG at recovery time xfs: don't use __GFP_RETRY_MAYFAIL in xfs_initialize_perag xfs: error out when a superblock buffer update reduces the agcount xfs: update the file system geometry after recoverying superblock buffers xfs: merge the perag freeing helpers xfs: pass the exact range to initialize to xfs_initialize_perag xfs: don't fail repairs on metadata files with no attr fork
2024-10-25Merge tag '9p-for-6.12-rc5' of https://github.com/martinetd/linuxLinus Torvalds5-87/+192
Pull more 9p reverts from Dominique Martinet: "Revert patches causing inode collision problems. The code simplification introduced significant regressions on servers that do not remap inode numbers when exporting multiple underlying filesystems with colliding inodes. See the top-most revert (commit be2ca3825372) for details. This problem had been ignored for too long and the reverts will also head to stable (6.9+). I'm confident this set of patches gets us back to previous behaviour (another related patch had already been reverted back in April and we're almost back to square 1, and the rest didn't touch inode lifecycle)" * tag '9p-for-6.12-rc5' of https://github.com/martinetd/linux: Revert "fs/9p: simplify iget to remove unnecessary paths" Revert "fs/9p: fix uaf in in v9fs_stat2inode_dotl" Revert "fs/9p: remove redundant pointer v9ses" Revert " fs/9p: mitigate inode collisions"
2024-10-25Merge tag 'v6.12-rc4-smb3-client-fixes' of git://git.samba.org/sfrench/cifs-2.6Linus Torvalds2-1/+8
Pull smb client fixes from Steve French: - Fix init module error caseb - Fix memory allocation error path (for passwords) in mount * tag 'v6.12-rc4-smb3-client-fixes' of git://git.samba.org/sfrench/cifs-2.6: cifs: fix warning when destroy 'cifs_io_request_pool' smb: client: Handle kstrdup failures for passwords
2024-10-25Merge tag 'fuse-fixes-6.12-rc5' of ↵Linus Torvalds4-17/+27
git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/fuse Pull fuse fixes from Miklos Szeredi: - Fix cached size after passthrough writes This fix needed a trivial change in the backing-file API, which resulted in some non-fuse files being touched. - Revert a commit meant as a cleanup but which triggered a WARNING - Remove a stray debug line left-over * tag 'fuse-fixes-6.12-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/fuse: fuse: remove stray debug line Revert "fuse: move initialization of fuse_file to fuse_writepages() instead of in callback" fuse: update inode size after extending passthrough write fs: pass offset and result to backing_file end_write() callback
2024-10-25Merge tag 'nfsd-6.12-2' of ↵Linus Torvalds2-9/+43
git://git.kernel.org/pub/scm/linux/kernel/git/cel/linux Pull nfsd fixes from Chuck Lever: - Fix a couple of use-after-free bugs * tag 'nfsd-6.12-2' of git://git.kernel.org/pub/scm/linux/kernel/git/cel/linux: nfsd: cancel nfsd_shrinker_work using sync mode in nfs4_state_shutdown_net nfsd: fix race between laundromat and free_stateid
2024-10-25bcachefs: Fix UAF in bch2_reconstruct_alloc()Kent Overstreet1-3/+2
write_super() -> sb_counters_from_cpu() may reallocate the superblock Reported-by: syzbot+9fc4dac4775d07bcfe34@syzkaller.appspotmail.com Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
2024-10-25bcachefs: fix null-ptr-deref in have_stripes()Jeongjun Park1-0/+3
c->btree_roots_known[i].b can be NULL. In this case, a NULL pointer dereference occurs, so you need to add code to check the variable. Reported-by: syzbot+b468b9fef56949c3b528@syzkaller.appspotmail.com Fixes: 7773df19c35f ("bcachefs: metadata version bucket_stripe_sectors") Signed-off-by: Jeongjun Park <aha310510@gmail.com> Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
2024-10-25fuse: remove stray debug lineMiklos Szeredi1-1/+0
It wasn't there when the patch was posted for review, but somehow made it into the pull. Link: https://lore.kernel.org/all/20240913104703.1673180-1-mszeredi@redhat.com/ Fixes: efad7153bf93 ("fuse: allow O_PATH fd for FUSE_DEV_IOC_BACKING_OPEN") Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2024-10-24bcachefs: fix shift oob in alloc_lru_idx_fragmentationJeongjun Park1-0/+3
The size of a.data_type is set abnormally large, causing shift-out-of-bounds. To fix this, we need to add validation on a.data_type in alloc_lru_idx_fragmentation(). Reported-by: syzbot+7f45fa9805c40db3f108@syzkaller.appspotmail.com Fixes: 260af1562ec1 ("bcachefs: Kill alloc_v4.fragmentation_lru") Signed-off-by: Jeongjun Park <aha310510@gmail.com> Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
2024-10-24bcachefs: Fix invalid shift in validate_sb_layout()Gianfranco Trad2-0/+6
Add check on layout->sb_max_size_bits against BCH_SB_LAYOUT_SIZE_BITS_MAX to prevent UBSAN shift-out-of-bounds in validate_sb_layout(). Reported-by: syzbot+089fad5a3a5e77825426@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=089fad5a3a5e77825426 Fixes: 03ef80b469d5 ("bcachefs: Ignore unknown mount options") Tested-by: syzbot+089fad5a3a5e77825426@syzkaller.appspotmail.com Signed-off-by: Gianfranco Trad <gianf.trad@gmail.com> Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
2024-10-25Revert "fs/9p: simplify iget to remove unnecessary paths"Dominique Martinet5-45/+180
This reverts commit 724a08450f74b02bd89078a596fd24857827c012. This code simplification introduced significant regressions on servers that do not remap inode numbers when exporting multiple underlying filesystems with colliding inodes, as can be illustrated with simple tmpfs exports in qemu with remapping disabled: ``` # host side cd /tmp/linux-test mkdir m1 m2 mount -t tmpfs tmpfs m1 mount -t tmpfs tmpfs m2 mkdir m1/dir m2/dir echo foo > m1/dir/foo echo bar > m2/dir/bar # guest side # started with -virtfs local,path=/tmp/linux-test,mount_tag=tmp,security_model=mapped-file mount -t 9p -o trans=virtio,debug=1 tmp /mnt/t ls /mnt/t/m1/dir # foo ls /mnt/t/m2/dir # bar (works ok if directry isn't open) # cd to keep first dir's inode alive cd /mnt/t/m1/dir ls /mnt/t/m2/dir # foo (should be bar) ``` Other examples can be crafted with regular files with fscache enabled, in which case I/Os just happen to the wrong file leading to corruptions, or guest failing to boot with: | VFS: Lookup of 'com.android.runtime' in 9p 9p would have caused loop In theory, we'd want the servers to be smart enough and ensure they never send us two different files with the same 'qid.path', but while qemu has an option to remap that is recommended (and qemu prints a warning if this case happens), there are many other servers which do not (kvmtool, nfs-ganesha, probably diod...), we should at least ensure we don't cause regressions on this: - assume servers can't be trusted and operations that should get a 'new' inode properly do so. commit d05dcfdf5e16 (" fs/9p: mitigate inode collisions") attempted to do this, but v9fs_fid_iget_dotl() was not called so some higher level of caching got in the way; this needs to be fixed properly before we can re-apply the patches. - if we ever want to really simplify this code, we will need to add some negotiation with the server at mount time where the server could claim they handle this properly, at which point we could optimize this out. (but that might not be needed at all if we properly handle the 'new' check?) Fixes: 724a08450f74 ("fs/9p: simplify iget to remove unnecessary paths") Reported-by: Will Deacon <will@kernel.org> Link: https://lore.kernel.org/all/20240408141436.GA17022@redhat.com/ Link: https://lkml.kernel.org/r/20240923100508.GA32066@willie-the-truck Cc: stable@vger.kernel.org # v6.9+ Message-ID: <20241024-revert_iget-v1-4-4cac63d25f72@codewreck.org> Signed-off-by: Dominique Martinet <asmadeus@codewreck.org>
2024-10-25Revert "fs/9p: fix uaf in in v9fs_stat2inode_dotl"Dominique Martinet1-1/+1
This reverts commit 11763a8598f888dec631a8a903f7ada32181001f. This is a requirement to revert commit 724a08450f74 ("fs/9p: simplify iget to remove unnecessary paths"), see that revert for details. Fixes: 724a08450f74 ("fs/9p: simplify iget to remove unnecessary paths") Reported-by: Will Deacon <will@kernel.org> Link: https://lkml.kernel.org/r/20240923100508.GA32066@willie-the-truck Cc: stable@vger.kernel.org # v6.9+ Message-ID: <20241024-revert_iget-v1-3-4cac63d25f72@codewreck.org> Signed-off-by: Dominique Martinet <asmadeus@codewreck.org>
2024-10-25Revert "fs/9p: remove redundant pointer v9ses"Dominique Martinet1-0/+4
This reverts commit 10211b4a23cf4a3df5c11a10e5b3d371f16a906f. This is a requirement to revert commit 724a08450f74 ("fs/9p: simplify iget to remove unnecessary paths"), see that revert for details. Fixes: 724a08450f74 ("fs/9p: simplify iget to remove unnecessary paths") Reported-by: Will Deacon <will@kernel.org> Link: https://lkml.kernel.org/r/20240923100508.GA32066@willie-the-truck Cc: stable@vger.kernel.org # v6.9+ Message-ID: <20241024-revert_iget-v1-2-4cac63d25f72@codewreck.org> Signed-off-by: Dominique Martinet <asmadeus@codewreck.org>
2024-10-25Revert " fs/9p: mitigate inode collisions"Dominique Martinet4-56/+22
This reverts commit d05dcfdf5e1659b2949d13060284eff3888b644e. This is a requirement to revert commit 724a08450f74 ("fs/9p: simplify iget to remove unnecessary paths"), see that revert for details. Fixes: 724a08450f74 ("fs/9p: simplify iget to remove unnecessary paths") Reported-by: Will Deacon <will@kernel.org> Link: https://lkml.kernel.org/r/20240923100508.GA32066@willie-the-truck Cc: stable@vger.kernel.org # v6.9+ Message-ID: <20241024-revert_iget-v1-1-4cac63d25f72@codewreck.org> Signed-off-by: Dominique Martinet <asmadeus@codewreck.org>
2024-10-24Merge tag 'for-6.12-rc4-tag' of ↵Linus Torvalds9-34/+45
git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux Pull btrfs fixes from David Sterba: - mount option fixes: - fix handling of compression mount options on remount - reject rw remount in case there are options that don't work in read-write mode (like rescue options) - fix zone accounting of unusable space - fix in-memory corruption when merging extent maps - fix delalloc range locking for sector < page - use more convenient default value of drop subtree threshold, clean more subvolumes without the fallback to marking quotas inconsistent - fix smatch warning about incorrect value passed to ERR_PTR * tag 'for-6.12-rc4-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux: btrfs: fix passing 0 to ERR_PTR in btrfs_search_dir_index_item() btrfs: reject ro->rw reconfiguration if there are hard ro requirements btrfs: fix read corruption due to race with extent map merging btrfs: fix the delalloc range locking if sector size < page size btrfs: qgroup: set a more sane default value for subtree drop threshold btrfs: clear force-compress on remount when compress mount option is given btrfs: zoned: fix zone unusable accounting for freed reserved extent
2024-10-24Merge tag 'jfs-6.12-rc5' of github.com:kleikamp/linux-shaggyLinus Torvalds1-1/+1
Pull jfs fix from David Kleikamp: "Fix a regression introduced in 6.12-rc1" * tag 'jfs-6.12-rc5' of github.com:kleikamp/linux-shaggy: jfs: Fix sanity check in dbMount
2024-10-24Merge tag 'bcachefs-2024-10-22' of https://github.com/koverstreet/bcachefsLinus Torvalds41-205/+475
Pull bcachefs fixes from Kent Overstreet: "Lots of hotfixes: - transaction restart injection has been shaking out a few things - fix a data corruption in the buffered write path on -ENOSPC, found by xfstests generic/299 - Some small show_options fixes - Repair mismatches in inode hash type, seed: different snapshot versions of an inode must have the same hash/type seed, used for directory entries and xattrs. We were checking the hash seed, but not the type, and a user contributed a filesystem where the hash type on one inode had somehow been flipped; these fixes allow his filesystem to repair. Additionally, the hash type flip made some directory entries invisible, which were then recreated by userspace; so the hash check code now checks for duplicate non dangling dirents, and renames one of them if necessary. - Don't use wait_event_interruptible() in recovery: this fixes some filesystems failing to mount with -ERESTARTSYS - Workaround for kvmalloc not supporting > INT_MAX allocations, causing an -ENOMEM when allocating the sorted array of journal keys: this allows a 75 TB filesystem to mount - Make sure bch_inode_unpacked.bi_snapshot is set in the old inode compat path: this alllows Marcin's filesystem (in use since before 6.7) to repair and mount" * tag 'bcachefs-2024-10-22' of https://github.com/koverstreet/bcachefs: (26 commits) bcachefs: Set bch_inode_unpacked.bi_snapshot in old inode path bcachefs: Mark more errors as AUTOFIX bcachefs: Workaround for kvmalloc() not supporting > INT_MAX allocations bcachefs: Don't use wait_event_interruptible() in recovery bcachefs: Fix __bch2_fsck_err() warning bcachefs: fsck: Improve hash_check_key() bcachefs: bch2_hash_set_or_get_in_snapshot() bcachefs: Repair mismatches in inode hash seed, type bcachefs: Add hash seed, type to inode_to_text() bcachefs: INODE_STR_HASH() for bch_inode_unpacked bcachefs: Run in-kernel offline fsck without ratelimit errors bcachefs: skip mount option handle for empty string. bcachefs: fix incorrect show_options results bcachefs: Fix data corruption on -ENOSPC in buffered write path bcachefs: bch2_folio_reservation_get_partial() is now better behaved bcachefs: fix disk reservation accounting in bch2_folio_reservation_get() bcachefS: ec: fix data type on stripe deletion bcachefs: Don't use commit_do() unnecessarily bcachefs: handle restarts in bch2_bucket_io_time_reset() bcachefs: fix restart handling in __bch2_resume_logged_op_finsert() ...
2024-10-24Revert "9p: Enable multipage folios"Dominique Martinet1-1/+0
This reverts commit 1325e4a91a405f88f1b18626904d37860a4f9069. using multipage folios apparently break some madvise operations like MADV_PAGEOUT which do not reliably unload the specified page anymore, Revert the patch until that is figured out. Reported-by: Andrii Nakryiko <andrii@kernel.org> Fixes: 1325e4a91a40 ("9p: Enable multipage folios") Signed-off-by: Dominique Martinet <asmadeus@codewreck.org> Acked-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2024-10-24afs: Fix missing subdir edit when renamed between parent dirsDavid Howells3-2/+116
When rename moves an AFS subdirectory between parent directories, the subdir also needs a bit of editing: the ".." entry needs updating to point to the new parent (though I don't make use of the info) and the DV needs incrementing by 1 to reflect the change of content. The server also sends a callback break notification on the subdirectory if we have one, but we can take care of recovering the promise next time we access the subdir. This can be triggered by something like: mount -t afs %example.com:xfstest.test20 /xfstest.test/ mkdir /xfstest.test/{aaa,bbb,aaa/ccc} touch /xfstest.test/bbb/ccc/d mv /xfstest.test/{aaa/ccc,bbb/ccc} touch /xfstest.test/bbb/ccc/e When the pathwalk for the second touch hits "ccc", kafs spots that the DV is incorrect and downloads it again (so the fix is not critical). Fix this, if the rename target is a directory and the old and new parents are different, by: (1) Incrementing the DV number of the target locally. (2) Editing the ".." entry in the target to refer to its new parent's vnode ID and uniquifier. Link: https://lore.kernel.org/r/3340431.1729680010@warthog.procyon.org.uk Fixes: 63a4681ff39c ("afs: Locally edit directory data for mkdir/create/unlink/...") cc: David Howells <dhowells@redhat.com> cc: Marc Dionne <marc.dionne@auristor.com> cc: linux-afs@lists.infradead.org Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-10-23btrfs: fix error propagation of split biosNaohiro Aota2-24/+16
The purpose of btrfs_bbio_propagate_error() shall be propagating an error of split bio to its original btrfs_bio, and tell the error to the upper layer. However, it's not working well on some cases. * Case 1. Immediate (or quick) end_bio with an error When btrfs sends btrfs_bio to mirrored devices, btrfs calls btrfs_bio_end_io() when all the mirroring bios are completed. If that btrfs_bio was split, it is from btrfs_clone_bioset and its end_io function is btrfs_orig_write_end_io. For this case, btrfs_bbio_propagate_error() accesses the orig_bbio's bio context to increase the error count. That works well in most cases. However, if the end_io is called enough fast, orig_bbio's (remaining part after split) bio context may not be properly set at that time. Since the bio context is set when the orig_bbio (the last btrfs_bio) is sent to devices, that might be too late for earlier split btrfs_bio's completion. That will result in NULL pointer dereference. That bug is easily reproducible by running btrfs/146 on zoned devices [1] and it shows the following trace. [1] You need raid-stripe-tree feature as it create "-d raid0 -m raid1" FS. BUG: kernel NULL pointer dereference, address: 0000000000000020 #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page PGD 0 P4D 0 Oops: Oops: 0000 [#1] PREEMPT SMP PTI CPU: 1 UID: 0 PID: 13 Comm: kworker/u32:1 Not tainted 6.11.0-rc7-BTRFS-ZNS+ #474 Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011 Workqueue: writeback wb_workfn (flush-btrfs-5) RIP: 0010:btrfs_bio_end_io+0xae/0xc0 [btrfs] BTRFS error (device dm-0): bdev /dev/mapper/error-test errs: wr 2, rd 0, flush 0, corrupt 0, gen 0 RSP: 0018:ffffc9000006f248 EFLAGS: 00010246 RAX: 0000000000000000 RBX: ffff888005a7f080 RCX: ffffc9000006f1dc RDX: 0000000000000000 RSI: 000000000000000a RDI: ffff888005a7f080 RBP: ffff888011dfc540 R08: 0000000000000000 R09: 0000000000000001 R10: ffffffff82e508e0 R11: 0000000000000005 R12: ffff88800ddfbe58 R13: ffff888005a7f080 R14: ffff888005a7f158 R15: ffff888005a7f158 FS: 0000000000000000(0000) GS:ffff88803ea80000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000020 CR3: 0000000002e22006 CR4: 0000000000370ef0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: <TASK> ? __die_body.cold+0x19/0x26 ? page_fault_oops+0x13e/0x2b0 ? _printk+0x58/0x73 ? do_user_addr_fault+0x5f/0x750 ? exc_page_fault+0x76/0x240 ? asm_exc_page_fault+0x22/0x30 ? btrfs_bio_end_io+0xae/0xc0 [btrfs] ? btrfs_log_dev_io_error+0x7f/0x90 [btrfs] btrfs_orig_write_end_io+0x51/0x90 [btrfs] dm_submit_bio+0x5c2/0xa50 [dm_mod] ? find_held_lock+0x2b/0x80 ? blk_try_enter_queue+0x90/0x1e0 __submit_bio+0xe0/0x130 ? ktime_get+0x10a/0x160 ? lockdep_hardirqs_on+0x74/0x100 submit_bio_noacct_nocheck+0x199/0x410 btrfs_submit_bio+0x7d/0x150 [btrfs] btrfs_submit_chunk+0x1a1/0x6d0 [btrfs] ? lockdep_hardirqs_on+0x74/0x100 ? __folio_start_writeback+0x10/0x2c0 btrfs_submit_bbio+0x1c/0x40 [btrfs] submit_one_bio+0x44/0x60 [btrfs] submit_extent_folio+0x13f/0x330 [btrfs] ? btrfs_set_range_writeback+0xa3/0xd0 [btrfs] extent_writepage_io+0x18b/0x360 [btrfs] extent_write_locked_range+0x17c/0x340 [btrfs] ? __pfx_end_bbio_data_write+0x10/0x10 [btrfs] run_delalloc_cow+0x71/0xd0 [btrfs] btrfs_run_delalloc_range+0x176/0x500 [btrfs] ? find_lock_delalloc_range+0x119/0x260 [btrfs] writepage_delalloc+0x2ab/0x480 [btrfs] extent_write_cache_pages+0x236/0x7d0 [btrfs] btrfs_writepages+0x72/0x130 [btrfs] do_writepages+0xd4/0x240 ? find_held_lock+0x2b/0x80 ? wbc_attach_and_unlock_inode+0x12c/0x290 ? wbc_attach_and_unlock_inode+0x12c/0x290 __writeback_single_inode+0x5c/0x4c0 ? do_raw_spin_unlock+0x49/0xb0 writeback_sb_inodes+0x22c/0x560 __writeback_inodes_wb+0x4c/0xe0 wb_writeback+0x1d6/0x3f0 wb_workfn+0x334/0x520 process_one_work+0x1ee/0x570 ? lock_is_held_type+0xc6/0x130 worker_thread+0x1d1/0x3b0 ? __pfx_worker_thread+0x10/0x10 kthread+0xee/0x120 ? __pfx_kthread+0x10/0x10 ret_from_fork+0x30/0x50 ? __pfx_kthread+0x10/0x10 ret_from_fork_asm+0x1a/0x30 </TASK> Modules linked in: dm_mod btrfs blake2b_generic xor raid6_pq rapl CR2: 0000000000000020 * Case 2. Earlier completion of orig_bbio for mirrored btrfs_bios btrfs_bbio_propagate_error() assumes the end_io function for orig_bbio is called last among split bios. In that case, btrfs_orig_write_end_io() sets the bio->bi_status to BLK_STS_IOERR by seeing the bioc->error [2]. Otherwise, the increased orig_bio's bioc->error is not checked by anyone and return BLK_STS_OK to the upper layer. [2] Actually, this is not true. Because we only increases orig_bioc->errors by max_errors, the condition "atomic_read(&bioc->error) > bioc->max_errors" is still not met if only one split btrfs_bio fails. * Case 3. Later completion of orig_bbio for un-mirrored btrfs_bios In contrast to the above case, btrfs_bbio_propagate_error() is not working well if un-mirrored orig_bbio is completed last. It sets orig_bbio->bio.bi_status to the btrfs_bio's error. But, that is easily over-written by orig_bbio's completion status. If the status is BLK_STS_OK, the upper layer would not know the failure. * Solution Considering the above cases, we can only save the error status in the orig_bbio (remaining part after split) itself as it is always available. Also, the saved error status should be propagated when all the split btrfs_bios are finished (i.e, bbio->pending_ios == 0). This commit introduces "status" to btrfs_bbio and saves the first error of split bios to original btrfs_bio's "status" variable. When all the split bios are finished, the saved status is loaded into original btrfs_bio's status. With this commit, btrfs/146 on zoned devices does not hit the NULL pointer dereference anymore. Fixes: 852eee62d31a ("btrfs: allow btrfs_submit_bio to split bios") CC: stable@vger.kernel.org # 6.6+ Reviewed-by: Qu Wenruo <wqu@suse.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com> Signed-off-by: David Sterba <dsterba@suse.com>
2024-10-23cifs: fix warning when destroy 'cifs_io_request_pool'Ye Bin1-1/+1
There's a issue as follows: WARNING: CPU: 1 PID: 27826 at mm/slub.c:4698 free_large_kmalloc+0xac/0xe0 RIP: 0010:free_large_kmalloc+0xac/0xe0 Call Trace: <TASK> ? __warn+0xea/0x330 mempool_destroy+0x13f/0x1d0 init_cifs+0xa50/0xff0 [cifs] do_one_initcall+0xdc/0x550 do_init_module+0x22d/0x6b0 load_module+0x4e96/0x5ff0 init_module_from_file+0xcd/0x130 idempotent_init_module+0x330/0x620 __x64_sys_finit_module+0xb3/0x110 do_syscall_64+0xc1/0x1d0 entry_SYSCALL_64_after_hwframe+0x77/0x7f Obviously, 'cifs_io_request_pool' is not created by mempool_create(). So just use mempool_exit() to revert 'cifs_io_request_pool'. Fixes: edea94a69730 ("cifs: Add mempools for cifs_io_request and cifs_io_subrequest structs") Signed-off-by: Ye Bin <yebin10@huawei.com> Acked-by: David Howells <dhowells@redhat.com Signed-off-by: Steve French <stfrench@microsoft.com>
2024-10-23smb: client: Handle kstrdup failures for passwordsHenrique Carvalho1-0/+7
In smb3_reconfigure(), after duplicating ctx->password and ctx->password2 with kstrdup(), we need to check for allocation failures. If ses->password allocation fails, return -ENOMEM. If ses->password2 allocation fails, free ses->password, set it to NULL, and return -ENOMEM. Fixes: c1eb537bf456 ("cifs: allow changing password during remount") Reviewed-by: David Howells <dhowells@redhat.com Signed-off-by: Haoxiang Li <make24@iscas.ac.cn> Signed-off-by: Henrique Carvalho <henrique.carvalho@suse.com> Signed-off-by: Steve French <stfrench@microsoft.com>
2024-10-22jfs: Fix sanity check in dbMountDave Kleikamp1-1/+1
MAXAG is a legitimate value for bmp->db_numag Fixes: e63866a47556 ("jfs: fix out-of-bounds in dbNextAG() and diAlloc()") Signed-off-by: Dave Kleikamp <dave.kleikamp@oracle.com>
2024-10-22btrfs: fix passing 0 to ERR_PTR in btrfs_search_dir_index_item()Yue Haibing2-7/+4
The ret may be zero in btrfs_search_dir_index_item() and should not passed to ERR_PTR(). Now btrfs_unlink_subvol() is the only caller to this, reconstructed it to check ERR_PTR(-ENOENT) while ret >= 0. This fixes smatch warnings: fs/btrfs/dir-item.c:353 btrfs_search_dir_index_item() warn: passing zero to 'ERR_PTR' Fixes: 9dcbe16fccbb ("btrfs: use btrfs_for_each_slot in btrfs_search_dir_index_item") CC: stable@vger.kernel.org # 6.1+ Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Signed-off-by: Yue Haibing <yuehaibing@huawei.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2024-10-22btrfs: reject ro->rw reconfiguration if there are hard ro requirementsQu Wenruo1-2/+1
[BUG] Syzbot reports the following crash: BTRFS info (device loop0 state MCS): disabling free space tree BTRFS info (device loop0 state MCS): clearing compat-ro feature flag for FREE_SPACE_TREE (0x1) BTRFS info (device loop0 state MCS): clearing compat-ro feature flag for FREE_SPACE_TREE_VALID (0x2) Oops: general protection fault, probably for non-canonical address 0xdffffc0000000003: 0000 [#1] PREEMPT SMP KASAN NOPTI KASAN: null-ptr-deref in range [0x0000000000000018-0x000000000000001f] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014 RIP: 0010:backup_super_roots fs/btrfs/disk-io.c:1691 [inline] RIP: 0010:write_all_supers+0x97a/0x40f0 fs/btrfs/disk-io.c:4041 Call Trace: <TASK> btrfs_commit_transaction+0x1eae/0x3740 fs/btrfs/transaction.c:2530 btrfs_delete_free_space_tree+0x383/0x730 fs/btrfs/free-space-tree.c:1312 btrfs_start_pre_rw_mount+0xf28/0x1300 fs/btrfs/disk-io.c:3012 btrfs_remount_rw fs/btrfs/super.c:1309 [inline] btrfs_reconfigure+0xae6/0x2d40 fs/btrfs/super.c:1534 btrfs_reconfigure_for_mount fs/btrfs/super.c:2020 [inline] btrfs_get_tree_subvol fs/btrfs/super.c:2079 [inline] btrfs_get_tree+0x918/0x1920 fs/btrfs/super.c:2115 vfs_get_tree+0x90/0x2b0 fs/super.c:1800 do_new_mount+0x2be/0xb40 fs/namespace.c:3472 do_mount fs/namespace.c:3812 [inline] __do_sys_mount fs/namespace.c:4020 [inline] __se_sys_mount+0x2d6/0x3c0 fs/namespace.c:3997 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f [CAUSE] To support mounting different subvolume with different RO/RW flags for the new mount APIs, btrfs introduced two workaround to support this feature: - Skip mount option/feature checks if we are mounting a different subvolume - Reconfigure the fs to RW if the initial mount is RO Combining these two, we can have the following sequence: - Mount the fs ro,rescue=all,clear_cache,space_cache=v1 rescue=all will mark the fs as hard read-only, so no v2 cache clearing will happen. - Mount a subvolume rw of the same fs. We go into btrfs_get_tree_subvol(), but fc_mount() returns EBUSY because our new fc is RW, different from the original fs. Now we enter btrfs_reconfigure_for_mount(), which switches the RO flag first so that we can grab the existing fs_info. Then we reconfigure the fs to RW. - During reconfiguration, option/features check is skipped This means we will restart the v2 cache clearing, and convert back to v1 cache. This will trigger fs writes, and since the original fs has "rescue=all" option, it skips the csum tree read. And eventually causing NULL pointer dereference in super block writeback. [FIX] For reconfiguration caused by different subvolume RO/RW flags, ensure we always run btrfs_check_options() to ensure we have proper hard RO requirements met. In fact the function btrfs_check_options() doesn't really do many complex checks, but hard RO requirement and some feature dependency checks, thus there is no special reason not to do the check for mount reconfiguration. Reported-by: syzbot+56360f93efa90ff15870@syzkaller.appspotmail.com Link: https://lore.kernel.org/linux-btrfs/0000000000008c5d090621cb2770@google.com/ Fixes: f044b318675f ("btrfs: handle the ro->rw transition for mounting different subvolumes") CC: stable@vger.kernel.org # 6.8+ Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Signed-off-by: Qu Wenruo <wqu@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2024-10-22btrfs: fix read corruption due to race with extent map mergingBoris Burkov1-15/+16
In debugging some corrupt squashfs files, we observed symptoms of corrupt page cache pages but correct on-disk contents. Further investigation revealed that the exact symptom was a correct page followed by an incorrect, duplicate, page. This got us thinking about extent maps. commit ac05ca913e9f ("Btrfs: fix race between using extent maps and merging them") enforces a reference count on the primary `em` extent_map being merged, as that one gets modified. However, since, commit 3d2ac9922465 ("btrfs: introduce new members for extent_map") both 'em' and 'merge' get modified, which started modifying 'merge' and thus introduced the same race. We were able to reproduce this by looping the affected squashfs workload in parallel on a bunch of separate btrfs-es while also dropping caches. We are still working on a simple enough reproducer to make into an fstest. The simplest fix is to stop modifying 'merge', which is not essential, as it is dropped immediately after the merge. This behavior is simply a consequence of the order of the two extent maps being important in computing the new values. Modify merge_ondisk_extents to take prev and next by const* and also take a third merged parameter that it puts the results in. Note that this introduces the rather odd behavior of passing 'em' to merge_ondisk_extents as a const * and as a regular ptr. Fixes: 3d2ac9922465 ("btrfs: introduce new members f