diff --git a/debian/patches/0018-dnode_is_dirty-check-dnode-and-its-data-for-dirtines.patch b/debian/patches/0018-dnode_is_dirty-check-dnode-and-its-data-for-dirtines.patch new file mode 100644 index 0000000..f79b09b --- /dev/null +++ b/debian/patches/0018-dnode_is_dirty-check-dnode-and-its-data-for-dirtines.patch @@ -0,0 +1,97 @@ +From 9b9b09f452a469458451c221debfbab944e7f081 Mon Sep 17 00:00:00 2001 +From: Rob N +Date: Wed, 29 Nov 2023 04:15:48 +1100 +Subject: [PATCH] dnode_is_dirty: check dnode and its data for dirtiness +MIME-Version: 1.0 +Content-Type: text/plain; charset=UTF-8 +Content-Transfer-Encoding: 8bit + +Over its history this the dirty dnode test has been changed between +checking for a dnodes being on `os_dirty_dnodes` (`dn_dirty_link`) and +`dn_dirty_record`. + + de198f2d9 Fix lseek(SEEK_DATA/SEEK_HOLE) mmap consistency + 2531ce372 Revert "Report holes when there are only metadata changes" + ec4f9b8f3 Report holes when there are only metadata changes + 454365bba Fix dirty check in dmu_offset_next() + 66aca2473 SEEK_HOLE should not block on txg_wait_synced() + +Also illumos/illumos-gate@c543ec060d illumos/illumos-gate@2bcf0248e9 + +It turns out both are actually required. + +In the case of appending data to a newly created file, the dnode proper +is dirtied (at least to change the blocksize) and dirty records are +added. Thus, a single logical operation is represented by separate +dirty indicators, and must not be separated. + +The incorrect dirty check becomes a problem when the first block of a +file is being appended to while another process is calling lseek to skip +holes. There is a small window where the dnode part is undirtied while +there are still dirty records. In this case, `lseek(fd, 0, SEEK_DATA)` +would not know that the file is dirty, and would go to +`dnode_next_offset()`. Since the object has no data blocks yet, it +returns `ESRCH`, indicating no data found, which results in `ENXIO` +being returned to `lseek()`'s caller. + +Since coreutils 9.2, `cp` performs sparse copies by default, that is, it +uses `SEEK_DATA` and `SEEK_HOLE` against the source file and attempts to +replicate the holes in the target. When it hits the bug, its initial +search for data fails, and it goes on to call `fallocate()` to create a +hole over the entire destination file. + +This has come up more recently as users upgrade their systems, getting +OpenZFS 2.2 as well as a newer coreutils. However, this problem has been +reproduced against 2.1, as well as on FreeBSD 13 and 14. + +This change simply updates the dirty check to check both types of dirty. +If there's anything dirty at all, we immediately go to the "wait for +sync" stage, It doesn't really matter after that; both changes are on +disk, so the dirty fields should be correct. + +Sponsored-by: Klara, Inc. +Sponsored-by: Wasabi Technology, Inc. +Reviewed-by: Brian Behlendorf +Reviewed-by: Alexander Motin +Reviewed-by: Rich Ercolani +Signed-off-by: Rob Norris +Closes #15571 +Closes #15526 +Signed-off-by: Fabian Grünbichler +--- + module/zfs/dnode.c | 12 ++++++++++-- + 1 file changed, 10 insertions(+), 2 deletions(-) + +diff --git a/module/zfs/dnode.c b/module/zfs/dnode.c +index 7cf03264d..ad9988366 100644 +--- a/module/zfs/dnode.c ++++ b/module/zfs/dnode.c +@@ -1764,7 +1764,14 @@ dnode_try_claim(objset_t *os, uint64_t object, int slots) + } + + /* +- * Checks if the dnode contains any uncommitted dirty records. ++ * Checks if the dnode itself is dirty, or is carrying any uncommitted records. ++ * It is important to check both conditions, as some operations (eg appending ++ * to a file) can dirty both as a single logical unit, but they are not synced ++ * out atomically, so checking one and not the other can result in an object ++ * appearing to be clean mid-way through a commit. ++ * ++ * Do not change this lightly! If you get it wrong, dmu_offset_next() can ++ * detect a hole where there is really data, leading to silent corruption. + */ + boolean_t + dnode_is_dirty(dnode_t *dn) +@@ -1772,7 +1779,8 @@ dnode_is_dirty(dnode_t *dn) + mutex_enter(&dn->dn_mtx); + + for (int i = 0; i < TXG_SIZE; i++) { +- if (multilist_link_active(&dn->dn_dirty_link[i])) { ++ if (multilist_link_active(&dn->dn_dirty_link[i]) || ++ !list_is_empty(&dn->dn_dirty_records[i])) { + mutex_exit(&dn->dn_mtx); + return (B_TRUE); + } +-- +2.39.2 + diff --git a/debian/patches/series b/debian/patches/series index d20a605..ac820c7 100644 --- a/debian/patches/series +++ b/debian/patches/series @@ -15,3 +15,4 @@ 0015-Fix-block-cloning-between-unencrypted-and-encrypted-.patch 0016-Add-a-tunable-to-disable-BRT-support.patch 0017-zfs-2.2.1-Disable-block-cloning-by-default.patch +0018-dnode_is_dirty-check-dnode-and-its-data-for-dirtines.patch