From 564d59410c39d1adb3e245f58663bad86636adaf Mon Sep 17 00:00:00 2001 From: Dan Carpenter Date: Thu, 27 Nov 2025 10:14:24 +0300 Subject: [PATCH 1/7] btrfs: tests: fix double btrfs_path free in remove_extent_ref() We converted this code to use auto free cleanup.h magic but one remaining free was accidentally left behind which leads to a double free bug. Fixes: a320476ca8a3 ("btrfs: tests: do trivial BTRFS_PATH_AUTO_FREE conversions") Signed-off-by: Dan Carpenter Reviewed-by: David Sterba Signed-off-by: David Sterba --- fs/btrfs/tests/qgroup-tests.c | 1 - 1 file changed, 1 deletion(-) diff --git a/fs/btrfs/tests/qgroup-tests.c b/fs/btrfs/tests/qgroup-tests.c index 05cfda8af422..e9124605974b 100644 --- a/fs/btrfs/tests/qgroup-tests.c +++ b/fs/btrfs/tests/qgroup-tests.c @@ -187,7 +187,6 @@ static int remove_extent_ref(struct btrfs_root *root, u64 bytenr, ret = btrfs_search_slot(&trans, root, &key, path, -1, 1); if (ret) { test_err("couldn't find backref %d", ret); - btrfs_free_path(path); return ret; } btrfs_del_item(&trans, root, path); From 266273eaf4d99475f1ae57f687b3e42bc71ec6f0 Mon Sep 17 00:00:00 2001 From: Filipe Manana Date: Thu, 27 Nov 2025 16:35:59 +0000 Subject: [PATCH 2/7] btrfs: don't log conflicting inode if it's a dir moved in the current transaction We can't log a conflicting inode if it's a directory and it was moved from one parent directory to another parent directory in the current transaction, as this can result an attempt to have a directory with two hard links during log replay, one for the old parent directory and another for the new parent directory. The following scenario triggers that issue: 1) We have directories "dir1" and "dir2" created in a past transaction. Directory "dir1" has inode A as its parent directory; 2) We move "dir1" to some other directory; 3) We create a file with the name "dir1" in directory inode A; 4) We fsync the new file. This results in logging the inode of the new file and the inode for the directory "dir1" that was previously moved in the current transaction. So the log tree has the INODE_REF item for the new location of "dir1"; 5) We move the new file to some other directory. This results in updating the log tree to included the new INODE_REF for the new location of the file and removes the INODE_REF for the old location. This happens during the rename when we call btrfs_log_new_name(); 6) We fsync the file, and that persists the log tree changes done in the previous step (btrfs_log_new_name() only updates the log tree in memory); 7) We have a power failure; 8) Next time the fs is mounted, log replay happens and when processing the inode for directory "dir1" we find a new INODE_REF and add that link, but we don't remove the old link of the inode since we have not logged the old parent directory of the directory inode "dir1". As a result after log replay finishes when we trigger writeback of the subvolume tree's extent buffers, the tree check will detect that we have a directory a hard link count of 2 and we get a mount failure. The errors and stack traces reported in dmesg/syslog are like this: [ 3845.729764] BTRFS info (device dm-0): start tree-log replay [ 3845.730304] page: refcount:3 mapcount:0 mapping:000000005c8a3027 index:0x1d00 pfn:0x11510c [ 3845.731236] memcg:ffff9264c02f4e00 [ 3845.731751] aops:btree_aops [btrfs] ino:1 [ 3845.732300] flags: 0x17fffc00000400a(uptodate|private|writeback|node=0|zone=2|lastcpupid=0x1ffff) [ 3845.733346] raw: 017fffc00000400a 0000000000000000 dead000000000122 ffff9264d978aea8 [ 3845.734265] raw: 0000000000001d00 ffff92650e6d4738 00000003ffffffff ffff9264c02f4e00 [ 3845.735305] page dumped because: eb page dump [ 3845.735981] BTRFS critical (device dm-0): corrupt leaf: root=5 block=30408704 slot=6 ino=257, invalid nlink: has 2 expect no more than 1 for dir [ 3845.737786] BTRFS info (device dm-0): leaf 30408704 gen 10 total ptrs 17 free space 14881 owner 5 [ 3845.737789] BTRFS info (device dm-0): refs 4 lock_owner 0 current 30701 [ 3845.737792] item 0 key (256 INODE_ITEM 0) itemoff 16123 itemsize 160 [ 3845.737794] inode generation 3 transid 9 size 16 nbytes 16384 [ 3845.737795] block group 0 mode 40755 links 1 uid 0 gid 0 [ 3845.737797] rdev 0 sequence 2 flags 0x0 [ 3845.737798] atime 1764259517.0 [ 3845.737800] ctime 1764259517.572889464 [ 3845.737801] mtime 1764259517.572889464 [ 3845.737802] otime 1764259517.0 [ 3845.737803] item 1 key (256 INODE_REF 256) itemoff 16111 itemsize 12 [ 3845.737805] index 0 name_len 2 [ 3845.737807] item 2 key (256 DIR_ITEM 2363071922) itemoff 16077 itemsize 34 [ 3845.737808] location key (257 1 0) type 2 [ 3845.737810] transid 9 data_len 0 name_len 4 [ 3845.737811] item 3 key (256 DIR_ITEM 2676584006) itemoff 16043 itemsize 34 [ 3845.737813] location key (258 1 0) type 2 [ 3845.737814] transid 9 data_len 0 name_len 4 [ 3845.737815] item 4 key (256 DIR_INDEX 2) itemoff 16009 itemsize 34 [ 3845.737816] location key (257 1 0) type 2 [ 3845.737818] transid 9 data_len 0 name_len 4 [ 3845.737819] item 5 key (256 DIR_INDEX 3) itemoff 15975 itemsize 34 [ 3845.737820] location key (258 1 0) type 2 [ 3845.737821] transid 9 data_len 0 name_len 4 [ 3845.737822] item 6 key (257 INODE_ITEM 0) itemoff 15815 itemsize 160 [ 3845.737824] inode generation 9 transid 10 size 6 nbytes 0 [ 3845.737825] block group 0 mode 40755 links 2 uid 0 gid 0 [ 3845.737826] rdev 0 sequence 1 flags 0x0 [ 3845.737827] atime 1764259517.572889464 [ 3845.737828] ctime 1764259517.572889464 [ 3845.737830] mtime 1764259517.572889464 [ 3845.737831] otime 1764259517.572889464 [ 3845.737832] item 7 key (257 INODE_REF 256) itemoff 15801 itemsize 14 [ 3845.737833] index 2 name_len 4 [ 3845.737834] item 8 key (257 INODE_REF 258) itemoff 15787 itemsize 14 [ 3845.737836] index 2 name_len 4 [ 3845.737837] item 9 key (257 DIR_ITEM 2507850652) itemoff 15754 itemsize 33 [ 3845.737838] location key (259 1 0) type 1 [ 3845.737839] transid 10 data_len 0 name_len 3 [ 3845.737840] item 10 key (257 DIR_INDEX 2) itemoff 15721 itemsize 33 [ 3845.737842] location key (259 1 0) type 1 [ 3845.737843] transid 10 data_len 0 name_len 3 [ 3845.737844] item 11 key (258 INODE_ITEM 0) itemoff 15561 itemsize 160 [ 3845.737846] inode generation 9 transid 10 size 8 nbytes 0 [ 3845.737847] block group 0 mode 40755 links 1 uid 0 gid 0 [ 3845.737848] rdev 0 sequence 1 flags 0x0 [ 3845.737849] atime 1764259517.572889464 [ 3845.737850] ctime 1764259517.572889464 [ 3845.737851] mtime 1764259517.572889464 [ 3845.737852] otime 1764259517.572889464 [ 3845.737853] item 12 key (258 INODE_REF 256) itemoff 15547 itemsize 14 [ 3845.737855] index 3 name_len 4 [ 3845.737856] item 13 key (258 DIR_ITEM 1843588421) itemoff 15513 itemsize 34 [ 3845.737857] location key (257 1 0) type 2 [ 3845.737858] transid 10 data_len 0 name_len 4 [ 3845.737860] item 14 key (258 DIR_INDEX 2) itemoff 15479 itemsize 34 [ 3845.737861] location key (257 1 0) type 2 [ 3845.737862] transid 10 data_len 0 name_len 4 [ 3845.737863] item 15 key (259 INODE_ITEM 0) itemoff 15319 itemsize 160 [ 3845.737865] inode generation 10 transid 10 size 0 nbytes 0 [ 3845.737866] block group 0 mode 100600 links 1 uid 0 gid 0 [ 3845.737867] rdev 0 sequence 2 flags 0x0 [ 3845.737868] atime 1764259517.580874966 [ 3845.737869] ctime 1764259517.586121869 [ 3845.737870] mtime 1764259517.580874966 [ 3845.737872] otime 1764259517.580874966 [ 3845.737873] item 16 key (259 INODE_REF 257) itemoff 15306 itemsize 13 [ 3845.737874] index 2 name_len 3 [ 3845.737875] BTRFS error (device dm-0): block=30408704 write time tree block corruption detected [ 3845.739448] ------------[ cut here ]------------ [ 3845.740092] WARNING: CPU: 5 PID: 30701 at fs/btrfs/disk-io.c:335 btree_csum_one_bio+0x25a/0x270 [btrfs] [ 3845.741439] Modules linked in: btrfs dm_flakey crc32c_cryptoapi (...) [ 3845.750626] CPU: 5 UID: 0 PID: 30701 Comm: mount Tainted: G W 6.18.0-rc6-btrfs-next-218+ #1 PREEMPT(full) [ 3845.752414] Tainted: [W]=WARN [ 3845.752828] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.2-0-gea1b7a073390-prebuilt.qemu.org 04/01/2014 [ 3845.754499] RIP: 0010:btree_csum_one_bio+0x25a/0x270 [btrfs] [ 3845.755460] Code: 31 f6 48 89 (...) [ 3845.758685] RSP: 0018:ffffa8d9c5677678 EFLAGS: 00010246 [ 3845.759450] RAX: 0000000000000000 RBX: ffff92650e6d4738 RCX: 0000000000000000 [ 3845.760309] RDX: 0000000000000000 RSI: ffffffff9aab45b9 RDI: ffff9264c4748000 [ 3845.761239] RBP: ffff9264d4324000 R08: 0000000000000000 R09: ffffa8d9c5677468 [ 3845.762607] R10: ffff926bdc1fffa8 R11: 0000000000000003 R12: ffffa8d9c5677680 [ 3845.764099] R13: 0000000000004000 R14: ffff9264dd624000 R15: ffff9264d978aba8 [ 3845.765094] FS: 00007f751fa5a840(0000) GS:ffff926c42a82000(0000) knlGS:0000000000000000 [ 3845.766226] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 3845.766970] CR2: 0000558df1815380 CR3: 000000010ed88003 CR4: 0000000000370ef0 [ 3845.768009] Call Trace: [ 3845.768392] [ 3845.768714] btrfs_submit_bbio+0x6ee/0x7f0 [btrfs] [ 3845.769640] ? write_one_eb+0x28e/0x340 [btrfs] [ 3845.770588] btree_write_cache_pages+0x2f0/0x550 [btrfs] [ 3845.771286] ? alloc_extent_state+0x19/0x100 [btrfs] [ 3845.771967] ? merge_next_state+0x1a/0x90 [btrfs] [ 3845.772586] ? set_extent_bit+0x233/0x8b0 [btrfs] [ 3845.773198] ? xas_load+0x9/0xc0 [ 3845.773589] ? xas_find+0x14d/0x1a0 [ 3845.773969] do_writepages+0xc6/0x160 [ 3845.774367] filemap_fdatawrite_wbc+0x48/0x60 [ 3845.775003] __filemap_fdatawrite_range+0x5b/0x80 [ 3845.775902] btrfs_write_marked_extents+0x61/0x170 [btrfs] [ 3845.776707] btrfs_write_and_wait_transaction+0x4e/0xc0 [btrfs] [ 3845.777379] ? _raw_spin_unlock_irqrestore+0x23/0x40 [ 3845.777923] btrfs_commit_transaction+0x5ea/0xd20 [btrfs] [ 3845.778551] ? _raw_spin_unlock+0x15/0x30 [ 3845.778986] ? release_extent_buffer+0x34/0x160 [btrfs] [ 3845.779659] btrfs_recover_log_trees+0x7a3/0x7c0 [btrfs] [ 3845.780416] ? __pfx_replay_one_buffer+0x10/0x10 [btrfs] [ 3845.781499] open_ctree+0x10bb/0x15f0 [btrfs] [ 3845.782194] btrfs_get_tree.cold+0xb/0x16c [btrfs] [ 3845.782764] ? fscontext_read+0x15c/0x180 [ 3845.783202] ? rw_verify_area+0x50/0x180 [ 3845.783667] vfs_get_tree+0x25/0xd0 [ 3845.784047] vfs_cmd_create+0x59/0xe0 [ 3845.784458] __do_sys_fsconfig+0x4f6/0x6b0 [ 3845.784914] do_syscall_64+0x50/0x1220 [ 3845.785340] entry_SYSCALL_64_after_hwframe+0x76/0x7e [ 3845.785980] RIP: 0033:0x7f751fc7f4aa [ 3845.786759] Code: 73 01 c3 48 (...) [ 3845.789951] RSP: 002b:00007ffcdba45dc8 EFLAGS: 00000246 ORIG_RAX: 00000000000001af [ 3845.791402] RAX: ffffffffffffffda RBX: 000055ccc8291c20 RCX: 00007f751fc7f4aa [ 3845.792688] RDX: 0000000000000000 RSI: 0000000000000006 RDI: 0000000000000003 [ 3845.794308] RBP: 000055ccc8292120 R08: 0000000000000000 R09: 0000000000000000 [ 3845.795829] R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 [ 3845.797183] R13: 00007f751fe11580 R14: 00007f751fe1326c R15: 00007f751fdf8a23 [ 3845.798633] [ 3845.799067] ---[ end trace 0000000000000000 ]--- [ 3845.800215] BTRFS: error (device dm-0) in btrfs_commit_transaction:2553: errno=-5 IO failure (Error while writing out transaction) [ 3845.801860] BTRFS warning (device dm-0 state E): Skipping commit of aborted transaction. [ 3845.802815] BTRFS error (device dm-0 state EA): Transaction aborted (error -5) [ 3845.803728] BTRFS: error (device dm-0 state EA) in cleanup_transaction:2036: errno=-5 IO failure [ 3845.805374] BTRFS: error (device dm-0 state EA) in btrfs_replay_log:2083: errno=-5 IO failure (Failed to recover log tree) [ 3845.807919] BTRFS error (device dm-0 state EA): open_ctree failed: -5 Fix this by never logging a conflicting inode that is a directory and was moved in the current transaction (its last_unlink_trans equals the current transaction) and instead fallback to a transaction commit. A test case for fstests will follow soon. Reported-by: Vyacheslav Kovalevsky Link: https://lore.kernel.org/linux-btrfs/7bbc9419-5c56-450a-b5a0-efeae7457113@gmail.com/ CC: stable@vger.kernel.org # 6.1+ Signed-off-by: Filipe Manana Signed-off-by: David Sterba --- fs/btrfs/tree-log.c | 38 ++++++++++++++++++++++++++++++++++++++ 1 file changed, 38 insertions(+) diff --git a/fs/btrfs/tree-log.c b/fs/btrfs/tree-log.c index fff37c8d96a4..64c1155160a2 100644 --- a/fs/btrfs/tree-log.c +++ b/fs/btrfs/tree-log.c @@ -6051,6 +6051,33 @@ static int conflicting_inode_is_dir(struct btrfs_root *root, u64 ino, return ret; } +static bool can_log_conflicting_inode(const struct btrfs_trans_handle *trans, + const struct btrfs_inode *inode) +{ + if (!S_ISDIR(inode->vfs_inode.i_mode)) + return true; + + if (inode->last_unlink_trans < trans->transid) + return true; + + /* + * If this is a directory and its unlink_trans is not from a past + * transaction then we must fallback to a transaction commit in order + * to avoid getting a directory with 2 hard links after log replay. + * + * This happens if a directory A is renamed, moved from one parent + * directory to another one, a new file is created in the old parent + * directory with the old name of our directory A, the new file is + * fsynced, then we moved the new file to some other parent directory + * and fsync again the new file. This results in a log tree where we + * logged that directory A existed, with the INODE_REF item for the + * new location but without having logged its old parent inode, so + * that on log replay we add a new link for the new location but the + * old link remains, resulting in a link count of 2. + */ + return false; +} + static int add_conflicting_inode(struct btrfs_trans_handle *trans, struct btrfs_root *root, struct btrfs_path *path, @@ -6154,6 +6181,11 @@ static int add_conflicting_inode(struct btrfs_trans_handle *trans, return 0; } + if (!can_log_conflicting_inode(trans, inode)) { + btrfs_add_delayed_iput(inode); + return BTRFS_LOG_FORCE_COMMIT; + } + btrfs_add_delayed_iput(inode); ino_elem = kmalloc(sizeof(*ino_elem), GFP_NOFS); @@ -6218,6 +6250,12 @@ static int log_conflicting_inodes(struct btrfs_trans_handle *trans, break; } + if (!can_log_conflicting_inode(trans, inode)) { + btrfs_add_delayed_iput(inode); + ret = BTRFS_LOG_FORCE_COMMIT; + break; + } + /* * Always log the directory, we cannot make this * conditional on need_log_inode() because the directory From 5630f7557de61264ccb4f031d4734a1a97eaed16 Mon Sep 17 00:00:00 2001 From: Filipe Manana Date: Wed, 3 Dec 2025 17:02:00 +0000 Subject: [PATCH 3/7] btrfs: do not skip logging new dentries when logging a new name When we are logging a directory and the log context indicates that we are logging a new name for some other file (that is or was inside that directory), we skip logging the inodes for new dentries in the directory. This is ok most of the time, but if after the rename or link operation that triggered the logging of that directory, we have an explicit fsync of that directory without the directory inode being evicted and reloaded, we end up never logging the inodes for the new dentries that we found during the new name logging, as the next directory fsync will only process dentries that were added after the last time we logged the directory (we are doing an incremental directory logging). So make sure we always log new dentries for a directory even if we are in a context of logging a new name. We started skipping logging inodes for new dentries as of commit c48792c6ee7a ("btrfs: do not log new dentries when logging that a new name exists") and it was fine back then, because when logging a directory we always iterated over all the directory entries (for leaves changed in the current transaction) so a subsequent fsync would always log anything that was previously skipped while logging a directory when logging a new name (with btrfs_log_new_name()). But later support for incrementally logging a directory was added in commit dc2872247ec0 ("btrfs: keep track of the last logged keys when logging a directory"), to avoid checking all dir items every time we log a directory, so the check to skip dentry logging added in the first commit should have been removed when the incremental support for logging a directory was added. A test case for fstests will follow soon. Reported-by: Vyacheslav Kovalevsky Link: https://lore.kernel.org/linux-btrfs/84c4e713-85d6-42b9-8dcf-0722ed26cb05@gmail.com/ Fixes: dc2872247ec0 ("btrfs: keep track of the last logged keys when logging a directory") Reviewed-by: Boris Burkov Signed-off-by: Filipe Manana Signed-off-by: David Sterba --- fs/btrfs/tree-log.c | 8 -------- 1 file changed, 8 deletions(-) diff --git a/fs/btrfs/tree-log.c b/fs/btrfs/tree-log.c index 64c1155160a2..31edc93a383e 100644 --- a/fs/btrfs/tree-log.c +++ b/fs/btrfs/tree-log.c @@ -5865,14 +5865,6 @@ static int log_new_dir_dentries(struct btrfs_trans_handle *trans, struct btrfs_inode *curr_inode = start_inode; int ret = 0; - /* - * If we are logging a new name, as part of a link or rename operation, - * don't bother logging new dentries, as we just want to log the names - * of an inode and that any new parents exist. - */ - if (ctx->logging_new_name) - return 0; - path = btrfs_alloc_path(); if (!path) return -ENOMEM; From 428e1b114c1ae94c44f0ae3a15dafcfae4d8a0b4 Mon Sep 17 00:00:00 2001 From: Qu Wenruo Date: Mon, 8 Dec 2025 19:55:48 +1030 Subject: [PATCH 4/7] Revert "btrfs: add ASSERTs on prealloc in qgroup functions" This reverts commit 252877a8701530fde861a4f27710c1e718e97caa. Commit 252877a87015 ("btrfs: add ASSERTs on prealloc in qgroup functions") tries to remove the kfree() on preallocated qgroup during several call sites, but this cannot work as intended: - btrfs_quota_enable() - btrfs_create_qgroup() If add_qgroup_item() failed, we go out_free_path() and at that time prealloc is not yet utilized and will trigger the new ASSERT(). - btrfs_qgroup_inherit() If qgroup_auto_inherit() failed, prealloc is not yet utilized and will trigger the new ASSERT() Reported-by: syzbot+b44d4a4885bc82af2a06@syzkaller.appspotmail.com Link: https://lore.kernel.org/linux-btrfs/69369331.a70a0220.38f243.009e.GAE@google.com/ Signed-off-by: Qu Wenruo Reviewed-by: David Sterba Signed-off-by: David Sterba --- fs/btrfs/qgroup.c | 27 ++++----------------------- 1 file changed, 4 insertions(+), 23 deletions(-) diff --git a/fs/btrfs/qgroup.c b/fs/btrfs/qgroup.c index 9e2b53e90dcb..d9d8d9968a58 100644 --- a/fs/btrfs/qgroup.c +++ b/fs/btrfs/qgroup.c @@ -1243,14 +1243,7 @@ int btrfs_quota_enable(struct btrfs_fs_info *fs_info, btrfs_end_transaction(trans); else if (trans) ret = btrfs_end_transaction(trans); - - /* - * At this point we either failed at allocating prealloc, or we - * succeeded and passed the ownership to it to add_qgroup_rb(). In any - * case, this needs to be NULL or there is something wrong. - */ - ASSERT(prealloc == NULL); - + kfree(prealloc); return ret; } @@ -1682,12 +1675,7 @@ int btrfs_create_qgroup(struct btrfs_trans_handle *trans, u64 qgroupid) ret = btrfs_sysfs_add_one_qgroup(fs_info, qgroup); out: mutex_unlock(&fs_info->qgroup_ioctl_lock); - /* - * At this point we either failed at allocating prealloc, or we - * succeeded and passed the ownership to it to add_qgroup_rb(). In any - * case, this needs to be NULL or there is something wrong. - */ - ASSERT(prealloc == NULL); + kfree(prealloc); return ret; } @@ -3279,7 +3267,7 @@ int btrfs_qgroup_inherit(struct btrfs_trans_handle *trans, u64 srcid, struct btrfs_root *quota_root; struct btrfs_qgroup *srcgroup; struct btrfs_qgroup *dstgroup; - struct btrfs_qgroup *prealloc = NULL; + struct btrfs_qgroup *prealloc; struct btrfs_qgroup_list **qlist_prealloc = NULL; bool free_inherit = false; bool need_rescan = false; @@ -3520,14 +3508,7 @@ int btrfs_qgroup_inherit(struct btrfs_trans_handle *trans, u64 srcid, } if (free_inherit) kfree(inherit); - - /* - * At this point we either failed at allocating prealloc, or we - * succeeded and passed the ownership to it to add_qgroup_rb(). In any - * case, this needs to be NULL or there is something wrong. - */ - ASSERT(prealloc == NULL); - + kfree(prealloc); return ret; } From 313ef70a9f0f637a09d9ef45222f5bdcf30a354b Mon Sep 17 00:00:00 2001 From: Qu Wenruo Date: Tue, 25 Nov 2025 18:49:56 +1030 Subject: [PATCH 5/7] btrfs: fix a potential path leak in print_data_reloc_error() Inside print_data_reloc_error(), if extent_from_logical() failed we return immediately. However there are the following cases where extent_from_logical() can return error but still holds a path: - btrfs_search_slot() returned 0 - No backref item found in extent tree - No flags_ret provided This is not possible in this call site though. So for the above two cases, we can return without releasing the path, causing extent buffer leaks. Fixes: b9a9a85059cd ("btrfs: output affected files when relocation fails") Signed-off-by: Qu Wenruo Reviewed-by: David Sterba Signed-off-by: David Sterba --- fs/btrfs/inode.c | 1 + 1 file changed, 1 insertion(+) diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c index 0cbac085cdaf..6633b3dc9314 100644 --- a/fs/btrfs/inode.c +++ b/fs/btrfs/inode.c @@ -255,6 +255,7 @@ static void print_data_reloc_error(const struct btrfs_inode *inode, u64 file_off if (ret < 0) { btrfs_err_rl(fs_info, "failed to lookup extent item for logical %llu: %d", logical, ret); + btrfs_release_path(&path); return; } eb = path.nodes[0]; From b57f2ddd28737db6ff0e9da8467f0ab9d707e997 Mon Sep 17 00:00:00 2001 From: Deepanshu Kartikey Date: Wed, 10 Dec 2025 18:58:07 +0530 Subject: [PATCH 6/7] btrfs: fix memory leak of fs_devices in degraded seed device path In open_seed_devices(), when find_fsid() fails and we're in DEGRADED mode, a new fs_devices is allocated via alloc_fs_devices() but is never added to the seed_list before returning. This contrasts with the normal path where fs_devices is properly added via list_add(). If any error occurs later in read_one_dev() or btrfs_read_chunk_tree(), the cleanup code iterates seed_list to free seed devices, but this orphaned fs_devices is never found and never freed, causing a memory leak. Any devices allocated via add_missing_dev() and attached to this fs_devices are also leaked. Fix this by adding the newly allocated fs_devices to seed_list in the degraded path, consistent with the normal path. Fixes: 5f37583569442 ("Btrfs: move the missing device to its own fs device list") Reported-by: syzbot+eadd98df8bceb15d7fed@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=eadd98df8bceb15d7fed Tested-by: syzbot+eadd98df8bceb15d7fed@syzkaller.appspotmail.com Reviewed-by: Qu Wenruo Signed-off-by: Deepanshu Kartikey Reviewed-by: David Sterba Signed-off-by: David Sterba --- fs/btrfs/volumes.c | 1 + 1 file changed, 1 insertion(+) diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c index e81c8ac0d8ae..e35872149e2f 100644 --- a/fs/btrfs/volumes.c +++ b/fs/btrfs/volumes.c @@ -7131,6 +7131,7 @@ static struct btrfs_fs_devices *open_seed_devices(struct btrfs_fs_info *fs_info, fs_devices->seeding = true; fs_devices->opened = 1; + list_add(&fs_devices->seed_list, &fs_info->fs_devices->seed_list); return fs_devices; } From 37343524f000d2a64359867d7024a73233d3b438 Mon Sep 17 00:00:00 2001 From: Filipe Manana Date: Thu, 11 Dec 2025 11:51:19 +0000 Subject: [PATCH 7/7] btrfs: fix changeset leak on mmap write after failure to reserve metadata If the call to btrfs_delalloc_reserve_metadata() fails we jump to the 'out_noreserve' label and there we never free the extent_changeset allocated by the previous call to btrfs_check_data_free_space() (if qgroups are enabled). Fix this by calling extent_changeset_free() under the 'out_noreserve' label. Fixes: 6599716de2d6 ("btrfs: fix -ENOSPC mmap write failure on NOCOW files/extents") Reported-by: syzbot+2f8aa76e6acc9fce6638@syzkaller.appspotmail.com Link: https://lore.kernel.org/linux-btrfs/693a635a.a70a0220.33cd7b.0029.GAE@google.com/ Reviewed-by: Qu Wenruo Signed-off-by: Filipe Manana Reviewed-by: David Sterba Signed-off-by: David Sterba --- fs/btrfs/file.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c index 1e0ff3d7210d..e42fd2beb1e3 100644 --- a/fs/btrfs/file.c +++ b/fs/btrfs/file.c @@ -2019,13 +2019,14 @@ static vm_fault_t btrfs_page_mkwrite(struct vm_fault *vmf) else btrfs_delalloc_release_space(inode, data_reserved, page_start, reserved_space, true); - extent_changeset_free(data_reserved); out_noreserve: if (only_release_metadata) btrfs_check_nocow_unlock(inode); sb_end_pagefault(inode->vfs_inode.i_sb); + extent_changeset_free(data_reserved); + if (ret < 0) return vmf_error(ret);