From 8ba8457d29c5976c57bfeb5034a6dc69e0c78577 Mon Sep 17 00:00:00 2001 From: Daan De Meyer Date: Wed, 4 Oct 2023 09:27:18 +0200 Subject: [PATCH] journal-file-util: Prefer punching holes instead of truncating It seems truncating might cause SIGBUS (#24320). Let's play it safe and always prefer punching holes over truncating. (cherry picked from commit f20c07d5ad3f657fdb9400288d7becb1b686d48a) Resolves: RHEL-11591 --- src/journal/managed-journal-file.c | 44 +++++++++++------------------- 1 file changed, 16 insertions(+), 28 deletions(-) diff --git a/src/journal/managed-journal-file.c b/src/journal/managed-journal-file.c index 382a7ff45b..0924b86f7c 100644 --- a/src/journal/managed-journal-file.c +++ b/src/journal/managed-journal-file.c @@ -19,22 +19,29 @@ #define PAYLOAD_BUFFER_SIZE (16U * 1024U) #define MINIMUM_HOLE_SIZE (1U * 1024U * 1024U / 2U) -static int managed_journal_file_truncate(JournalFile *f) { - uint64_t p; +static int managed_journal_file_end_punch_hole(JournalFile *f) { + uint64_t p, sz; int r; - /* truncate excess from the end of archives */ r = journal_file_tail_end_by_pread(f, &p); if (r < 0) return log_debug_errno(r, "Failed to determine end of tail object: %m"); - /* arena_size can't exceed the file size, ensure it's updated before truncating */ - f->header->arena_size = htole64(p - le64toh(f->header->header_size)); + assert(p <= (uint64_t) f->last_stat.st_size); + + sz = ((uint64_t) f->last_stat.st_size) - p; + if (sz < MINIMUM_HOLE_SIZE) + return 0; + + if (fallocate(f->fd, FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE, p, sz) < 0) { + if (ERRNO_IS_NOT_SUPPORTED(errno)) + return log_debug_errno(SYNTHETIC_ERRNO(EOPNOTSUPP), /* Make recognizable */ + "Hole punching not supported by backing file system, skipping."); - if (ftruncate(f->fd, p) < 0) - return log_debug_errno(errno, "Failed to truncate %s: %m", f->path); + return log_debug_errno(errno, "Failed to punch hole at end of journal file %s: %m", f->path); + } - return journal_file_fstat(f); + return 0; } static int managed_journal_file_entry_array_punch_hole(JournalFile *f, uint64_t p, uint64_t n_entries) { @@ -73,25 +80,6 @@ static int managed_journal_file_entry_array_punch_hole(JournalFile *f, uint64_t if (sz < MINIMUM_HOLE_SIZE) return 0; - if (p == le64toh(f->header->tail_object_offset) && !JOURNAL_HEADER_SEALED(f->header)) { - ssize_t n; - - o.object.size = htole64(offset - p); - - n = pwrite(f->fd, &o, sizeof(EntryArrayObject), p); - if (n < 0) - return log_debug_errno(errno, "Failed to modify entry array object size: %m"); - if ((size_t) n != sizeof(EntryArrayObject)) - return log_debug_errno(SYNTHETIC_ERRNO(EIO), "Short pwrite() while modifying entry array object size."); - - f->header->arena_size = htole64(ALIGN64(offset) - le64toh(f->header->header_size)); - - if (ftruncate(f->fd, ALIGN64(offset)) < 0) - return log_debug_errno(errno, "Failed to truncate %s: %m", f->path); - - return 0; - } - if (fallocate(f->fd, FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE, offset, sz) < 0) { if (ERRNO_IS_NOT_SUPPORTED(errno)) return log_debug_errno(SYNTHETIC_ERRNO(EOPNOTSUPP), /* Make recognizable */ @@ -192,7 +180,7 @@ static void managed_journal_file_set_offline_internal(ManagedJournalFile *f) { case OFFLINE_SYNCING: if (f->file->archive) { - (void) managed_journal_file_truncate(f->file); + (void) managed_journal_file_end_punch_hole(f->file); (void) managed_journal_file_punch_holes(f->file); }