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journal-file-util: Prefer punching holes instead of truncating

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It seems truncating might cause SIGBUS (#24320). Let's play it safe
and always prefer punching holes over truncating.
This commit is contained in:
Daan De Meyer
2023-10-04 09:27:18 +02:00
committed by Yu Watanabe
parent 46e98dfcc7
commit f20c07d5ad
1 changed files with 16 additions and 28 deletions
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44
src/shared/journal-file-util.c
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@@ -19,22 +19,29 @@
#define PAYLOAD_BUFFER_SIZE (16U * 1024U)
#define MINIMUM_HOLE_SIZE (1U * 1024U * 1024U / 2U)
static int journal_file_truncate(JournalFile *f) {
uint64_t p;
static int 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);
if (ftruncate(f->fd, p) < 0)
return log_debug_errno(errno, "Failed to truncate %s: %m", f->path);
sz = ((uint64_t) f->last_stat.st_size) - p;
if (sz < MINIMUM_HOLE_SIZE)
return 0;
return journal_file_fstat(f);
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.");
return log_debug_errno(errno, "Failed to punch hole at end of journal file %s: %m", f->path);
}
return 0;
}
static int journal_file_entry_array_punch_hole(JournalFile *f, uint64_t p, uint64_t n_entries) {
@@ -73,25 +80,6 @@ static int journal_file_entry_array_punch_hole(JournalFile *f, uint64_t p, uint6
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 journal_file_set_offline_internal(JournalFile *f) {
case OFFLINE_SYNCING:
if (f->archive) {
(void) journal_file_truncate(f);
(void) journal_file_end_punch_hole(f);
(void) journal_file_punch_holes(f);
}