-----Original Message-----
> This option can be used to ensure that a certain amount of free space is
> preserved. It is useful when the output of makedumpfile is on the root
> filesystem and some services fail to start at boot if there is no space
> left.
Thanks for the patch, the option seems nice!
Some comments inline.
>
> Signed-off-by: Benjamin Poirier <bpoirier@xxxxxxxxxx>
> ---
> makedumpfile.8 | 12 +++++++++---
> makedumpfile.c | 50 ++++++++++++++++++++++++++++++++++++++++++++------
> makedumpfile.h | 2 ++
> print_info.c | 3 +++
> 4 files changed, 58 insertions(+), 9 deletions(-)
>
> diff --git a/makedumpfile.8 b/makedumpfile.8
> index 313a41c..9a90f0e 100644
> --- a/makedumpfile.8
> +++ b/makedumpfile.8
> @@ -157,9 +157,10 @@ will be effective if you specify domain-0's \fIvmlinux\fR with \-x option.
> Then the pages are excluded only from domain-0.
> .br
> If specifying multiple dump_levels with the delimiter ',', makedumpfile retries
> -to create a \fIDUMPFILE\fR by other dump_level when "No space on device" error
> -happens. For example, if dump_level is "11,31" and makedumpfile fails
> -by dump_level 11, makedumpfile retries it by dump_level 31.
> +to create \fIDUMPFILE\fR using the next dump_level when the size of a dumpfile
> +exceeds the limit specified with '-L' or when when a "No space on device" error
> +happens. For example, if dump_level is "11,31" and makedumpfile fails with
> +dump_level 11, makedumpfile retries with dump_level 31.
> .br
> .B Example:
> .br
> @@ -221,6 +222,11 @@ Here is the all combinations of the bits.
> 30 | | X | X | X | X
> 31 | X | X | X | X | X
>
> +.TP
> +\fB\-L\fR \fISIZE\fR
> +Limit the size of the output file to \fISIZE\fR bytes. An incomplete
> +\fIDUMPFILE\fR or \fILOGFILE\fR is written if the size would otherwise exceed
> +\fISIZE\fR.
>
> .TP
> \fB\-E\fR
> diff --git a/makedumpfile.c b/makedumpfile.c
> index 894c88e..8a443c6 100644
> --- a/makedumpfile.c
> +++ b/makedumpfile.c
> @@ -22,6 +22,8 @@
> #include "cache.h"
> #include <stddef.h>
> #include <ctype.h>
> +#include <signal.h>
> +#include <sys/resource.h>
> #include <sys/time.h>
> #include <limits.h>
> #include <assert.h>
> @@ -1383,6 +1385,28 @@ open_dump_file(void)
> return FALSE;
> }
> info->fd_dumpfile = fd;
> +
> + if (info->size_limit != -1) {
> + struct sigaction act = {
> + .sa_handler = SIG_IGN,
> + };
> + struct rlimit rlim = {
> + .rlim_cur = info->size_limit,
> + .rlim_max = info->size_limit,
> + };
> +
> + if (sigaction(SIGXFSZ, &act, NULL)) {
> + ERRMSG("Can't ignore SIGXFSZ. %s\n", strerror(errno));
> + return FALSE;
> + }
> +
> + if (setrlimit(RLIMIT_FSIZE, &rlim)) {
> + ERRMSG("Can't set file size limit(%lld). %s\n",
> + (long long) info->size_limit, strerror(errno));
> + return FALSE;
> + }
> + }
> +
> return TRUE;
> }
>
> @@ -4729,7 +4753,7 @@ write_and_check_space(int fd, void *buf, size_t buf_size, char *file_name)
> written_size += status;
> continue;
> }
> - if (errno == ENOSPC)
> + if (errno == ENOSPC || errno == EFBIG)
> info->flag_nospace = TRUE;
> MSG("\nCan't write the dump file(%s). %s\n",
> file_name, strerror(errno));
> @@ -5308,7 +5332,7 @@ dump_log_entry(char *logptr, int fp)
> for (i = 0, p = msg; i < text_len; i++, p++) {
> if (bufp - buf >= sizeof(buf) - buf_need) {
> if (write(info->fd_dumpfile, buf, bufp - buf) < 0)
> - return FALSE;
> + goto out_fail;
> bufp = buf;
> }
>
> @@ -5322,10 +5346,13 @@ dump_log_entry(char *logptr, int fp)
>
> *bufp++ = '\n';
>
> - if (write(info->fd_dumpfile, buf, bufp - buf) < 0)
> - return FALSE;
> - else
> + if (write(info->fd_dumpfile, buf, bufp - buf) >= 0)
> return TRUE;
> +
> +out_fail:
> + ERRMSG("\nCan't write the log file(%s). %s\n", info->name_dumpfile,
> + strerror(errno));
> + return FALSE;
> }
This change in dump_log_entry() looks ok, but the function supports only
Linux 3.5 to 5.9 kernels. The other kernels are supported by the other
function or path:
dump_dmesg()
...
if ((SYMBOL(prb) != NOT_FOUND_SYMBOL))
return dump_lockless_dmesg(); <<-- 5.10 and newer
...
if (info->kernel_version < KERNEL_VERSION(3, 5, 0)) {
...
if (write(info->fd_dumpfile, log_buffer, length_log) < 0) <<-- 3.4 and older
goto out;
Could you add support for those kernels? if you need the -L option for
the --dump-dmesg option.
But it seems that write() with RLIMIT_FSIZE returns the rest size to
the limit first, and returns -1 with EFBIG next time. So a change
might be needed for the write() above.
>
> /*
> @@ -11585,6 +11612,7 @@ main(int argc, char *argv[])
> }
> info->file_vmcoreinfo = NULL;
> info->fd_vmlinux = -1;
> + info->size_limit = -1;
> info->fd_xen_syms = -1;
> info->fd_memory = -1;
> info->fd_dumpfile = -1;
> @@ -11605,9 +11633,11 @@ main(int argc, char *argv[])
>
> info->block_order = DEFAULT_ORDER;
> message_level = DEFAULT_MSG_LEVEL;
> - while ((opt = getopt_long(argc, argv, "b:cDd:eEFfg:hi:lpRvXx:", longopts,
> + while ((opt = getopt_long(argc, argv, "b:cDd:eEFfg:hi:lL:pRvXx:", longopts,
> NULL)) != -1) {
> switch (opt) {
> + long long val;
> +
> case OPT_BLOCK_ORDER:
> info->block_order = atoi(optarg);
> break;
> @@ -11624,6 +11654,14 @@ main(int argc, char *argv[])
> if (!parse_dump_level(optarg))
> goto out;
> break;
> + case OPT_SIZE_LIMIT:
> + val = atoll(optarg);
> + if (val < 0) {
The atoll() returns 0 if the optarg is an invalid string and "-L 0" is
also meaningless, so I'd prefer (val <= 0) here.
Thanks,
Kazu
> + MSG("Limit size(%lld) is invalid.\n", val);
> + goto out;
> + }
> + info->size_limit = val;
> + break;
> case OPT_ELF_DUMPFILE:
> info->flag_elf_dumpfile = 1;
> break;
> diff --git a/makedumpfile.h b/makedumpfile.h
> index 79046f2..7357ee7 100644
> --- a/makedumpfile.h
> +++ b/makedumpfile.h
> @@ -1344,6 +1344,7 @@ struct DumpInfo {
> int max_dump_level; /* maximum dump level */
> int num_dump_level; /* number of dump level */
> int array_dump_level[NUM_ARRAY_DUMP_LEVEL];
> + off_t size_limit; /* dump file size limit */
> int flag_compress; /* flag of compression */
> int flag_lzo_support; /* flag of LZO compression support */
> int flag_elf_dumpfile; /* flag of creating ELF dumpfile */
> @@ -2458,6 +2459,7 @@ struct elf_prstatus {
> #define OPT_HELP 'h'
> #define OPT_READ_VMCOREINFO 'i'
> #define OPT_COMPRESS_LZO 'l'
> +#define OPT_SIZE_LIMIT 'L'
> #define OPT_COMPRESS_SNAPPY 'p'
> #define OPT_REARRANGE 'R'
> #define OPT_VERSION 'v'
> diff --git a/print_info.c b/print_info.c
> index ad4184e..8b28554 100644
> --- a/print_info.c
> +++ b/print_info.c
> @@ -144,6 +144,9 @@ print_usage(void)
> MSG(" 16 | X\n");
> MSG(" 31 | X X X X X\n");
> MSG("\n");
> + MSG(" [-L SIZE]:\n");
> + MSG(" Limit the size of the output file to SIZE bytes.\n");
> + MSG("\n");
> MSG(" [-E]:\n");
> MSG(" Create DUMPFILE in the ELF format.\n");
> MSG(" This option cannot be specified with the -c, -l or -p options,\n");
> --
> 2.32.0.rc0
>
>
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