Date: Fri, 1 Dec 2023 00:38:55 GMT From: Gordon Tetlow <gordon@FreeBSD.org> To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-branches@FreeBSD.org Subject: git: 7769487a50ff - releng/12.4 - dnode_is_dirty: check dnode and its data for dirtiness Message-ID: <202312010038.3B10ctNZ057181@gitrepo.freebsd.org>
next in thread | raw e-mail | index | archive | help
The branch releng/12.4 has been updated by gordon: URL: https://cgit.FreeBSD.org/src/commit/?id=7769487a50ff81a31c313538d914f0dc8deb5ea1 commit 7769487a50ff81a31c313538d914f0dc8deb5ea1 Author: Rob Norris <rob.norris@klarasystems.com> AuthorDate: 2023-11-30 05:14:13 +0000 Commit: Gordon Tetlow <gordon@FreeBSD.org> CommitDate: 2023-11-30 21:46:13 +0000 dnode_is_dirty: check dnode and its data for dirtiness 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`. 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. 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. Approved by: so Security: FreeBSD-EN-23:16.openzfs (cherry picked from commit 8959056352256e79a63ba6327f0a0ee4236d3e7f) --- sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dmu.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dmu.c b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dmu.c index 45ac4b796fd2..bd78daf5d517 100644 --- a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dmu.c +++ b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dmu.c @@ -2557,7 +2557,8 @@ dmu_object_wait_synced(objset_t *os, uint64_t object) } for (i = 0; i < TXG_SIZE; i++) { - if (list_link_active(&dn->dn_dirty_link[i])) { + if (list_link_active(&dn->dn_dirty_link[i]) || + !list_is_empty(&dn->dn_dirty_records[i])) { break; } }
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?202312010038.3B10ctNZ057181>