Re: [PATCH] metadump: handle corruption errors without aborting

Sean Caron
2022-02-02T18:50:02Z

Hi Dave,

Thank you! I tried copying and pasting this into a file and applying it with:

patch < thispatchfile

against both the 5.14.2 release and xfsprogs-dev Git pull and I'm
getting errors from patch.

I also tried using "git patch" and it told me the patch does not apply.

I tried applying the patch by hand to the 5.14.2 metadump.c but I get
a compilation error in process_dev_inode but I'm not sure if that's
because I made a mistake or because the patch is expecting other
content to be there, that isn't.

I'm sorry for the ignorance but how would I make use of this?

Thanks,

Sean

On Wed, Feb 2, 2022 at 2:42 AM Dave Chinner <david@fromorbit.com> wrote:
>
>
> From: Dave Chinner <dchinner@redhat.com>
>
> Sean Caron reported that a metadump terminated after givin gthis
> warning:
>
> xfs_metadump: inode 2216156864 has unexpected extents
>
> Metadump is supposed to ignore corruptions and continue dumping the
> filesystem as best it can. Whilst it warns about many situations
> where it can't fully dump structures, it should stop processing that
> structure and continue with the next one until the entire filesystem
> has been processed.
>
> Unfortunately, some warning conditions also return an "abort" error
> status, causing metadump to abort if that condition is hit. Most of
> these abort conditions should really be "continue on next object"
> conditions so that the we attempt to dump the rest of the
> filesystem.
>
> Fix the returns for warnings that incorrectly cause aborts
> such that the only abort conditions are read errors when
> "stop-on-read-error" semantics are specified. Also make the return
> values consistently mean abort/continue rather than returning -errno
> to mean "stop because read error" and then trying to infer what
> the error means in callers without the context it occurred in.
>
> Reported-by: Sean Caron <scaron@umich.edu>
> Signed-off-by: Dave Chinner <dchinner@redhat.com>
> ---
>
> Sean,
>
> Can you please apply this patch to your xfsprogs source tree and
> rebuild it? This should let metadump continue past the corrupt
> inodes it aborted on and run through to completion.
>
> -Dave.
>
> db/metadump.c | 94 +++++++++++++++++++++++++++++------------------------------
> 1 file changed, 47 insertions(+), 47 deletions(-)
>
> diff --git a/db/metadump.c b/db/metadump.c
> index 96b098b0eaca..9b32b88a3c50 100644
> --- a/db/metadump.c
> +++ b/db/metadump.c
> @@ -1645,7 +1645,7 @@ process_symlink_block(
> {
> struct bbmap map;
> char *link;
> - int ret = 0;
> + int rval = 1;
>
> push_cur();
> map.nmaps = 1;
> @@ -1658,8 +1658,7 @@ process_symlink_block(
>
> print_warning("cannot read %s block %u/%u (%llu)",
> typtab[btype].name, agno, agbno, s);
> - if (stop_on_read_error)
> - ret = -1;
> + rval = !stop_on_read_error;
> goto out_pop;
> }
> link = iocur_top->data;
> @@ -1682,10 +1681,11 @@ process_symlink_block(
> }
>
> iocur_top->need_crc = 1;
> - ret = write_buf(iocur_top);
> + if (write_buf(iocur_top))
> + rval = 0;
> out_pop:
> pop_cur();
> - return ret;
> + return rval;
> }
>
> #define MAX_REMOTE_VALS 4095
> @@ -1843,8 +1843,8 @@ process_single_fsb_objects(
> typnm_t btype,
> xfs_fileoff_t last)
> {
> + int rval = 1;
> char *dp;
> - int ret = 0;
> int i;
>
> for (i = 0; i < c; i++) {
> @@ -1858,8 +1858,7 @@ process_single_fsb_objects(
>
> print_warning("cannot read %s block %u/%u (%llu)",
> typtab[btype].name, agno, agbno, s);
> - if (stop_on_read_error)
> - ret = -EIO;
> + rval = !stop_on_read_error;
> goto out_pop;
>
> }
> @@ -1925,16 +1924,17 @@ process_single_fsb_objects(
> }
>
> write:
> - ret = write_buf(iocur_top);
> + if (write_buf(iocur_top))
> + rval = 0;
> out_pop:
> pop_cur();
> - if (ret)
> + if (!rval)
> break;
> o++;
> s++;
> }
>
> - return ret;
> + return rval;
> }
>
> /*
> @@ -1952,7 +1952,7 @@ process_multi_fsb_dir(
> xfs_fileoff_t last)
> {
> char *dp;
> - int ret = 0;
> + int rval = 1;
>
> while (c > 0) {
> unsigned int bm_len;
> @@ -1978,8 +1978,7 @@ process_multi_fsb_dir(
>
> print_warning("cannot read %s block %u/%u (%llu)",
> typtab[btype].name, agno, agbno, s);
> - if (stop_on_read_error)
> - ret = -1;
> + rval = !stop_on_read_error;
> goto out_pop;
>
> }
> @@ -1998,18 +1997,19 @@ process_multi_fsb_dir(
> }
> iocur_top->need_crc = 1;
> write:
> - ret = write_buf(iocur_top);
> + if (write_buf(iocur_top))
> + rval = 0;
> out_pop:
> pop_cur();
> mfsb_map.nmaps = 0;
> - if (ret)
> + if (!rval)
> break;
> }
> c -= bm_len;
> s += bm_len;
> }
>
> - return ret;
> + return rval;
> }
>
> static bool
> @@ -2039,15 +2039,15 @@ process_multi_fsb_objects(
> return process_symlink_block(o, s, c, btype, last);
> default:
> print_warning("bad type for multi-fsb object %d", btype);
> - return -EINVAL;
> + return 1;
> }
> }
>
> /* inode copy routines */
> static int
> process_bmbt_reclist(
> - xfs_bmbt_rec_t *rp,
> - int numrecs,
> + xfs_bmbt_rec_t *rp,
> + int numrecs,
> typnm_t btype)
> {
> int i;
> @@ -2059,7 +2059,7 @@ process_bmbt_reclist(
> xfs_agnumber_t agno;
> xfs_agblock_t agbno;
> bool is_multi_fsb = is_multi_fsb_object(mp, btype);
> - int error;
> + int rval = 1;
>
> if (btype == TYP_DATA)
> return 1;
> @@ -2123,16 +2123,16 @@ process_bmbt_reclist(
>
> /* multi-extent blocks require special handling */
> if (is_multi_fsb)
> - error = process_multi_fsb_objects(o, s, c, btype,
> + rval = process_multi_fsb_objects(o, s, c, btype,
> last);
> else
> - error = process_single_fsb_objects(o, s, c, btype,
> + rval = process_single_fsb_objects(o, s, c, btype,
> last);
> - if (error)
> - return 0;
> + if (!rval)
> + break;
> }
>
> - return 1;
> + return rval;
> }
>
> static int
> @@ -2331,7 +2331,7 @@ process_inode_data(
> return 1;
> }
>
> -static int
> +static void
> process_dev_inode(
> xfs_dinode_t *dip)
> {
> @@ -2339,15 +2339,13 @@ process_dev_inode(
> if (show_warnings)
> print_warning("inode %llu has unexpected extents",
> (unsigned long long)cur_ino);
> - return 0;
> - } else {
> - if (zero_stale_data) {
> - unsigned int size = sizeof(xfs_dev_t);
> + return;
> + }
> + if (zero_stale_data) {
> + unsigned int size = sizeof(xfs_dev_t);
>
> - memset(XFS_DFORK_DPTR(dip) + size, 0,
> - XFS_DFORK_DSIZE(dip, mp) - size);
> - }
> - return 1;
> + memset(XFS_DFORK_DPTR(dip) + size, 0,
> + XFS_DFORK_DSIZE(dip, mp) - size);
> }
> }
>
> @@ -2365,11 +2363,10 @@ process_inode(
> xfs_dinode_t *dip,
> bool free_inode)
> {
> - int success;
> + int rval = 1;
> bool crc_was_ok = false; /* no recalc by default */
> bool need_new_crc = false;
>
> - success = 1;
> cur_ino = XFS_AGINO_TO_INO(mp, agno, agino);
>
> /* we only care about crc recalculation if we will modify the inode. */
> @@ -2390,32 +2387,34 @@ process_inode(
> /* copy appropriate data fork metadata */
> switch (be16_to_cpu(dip->di_mode) & S_IFMT) {
> case S_IFDIR:
> - success = process_inode_data(dip, TYP_DIR2);
> + rval = process_inode_data(dip, TYP_DIR2);
> if (dip->di_format == XFS_DINODE_FMT_LOCAL)
> need_new_crc = 1;
> break;
> case S_IFLNK:
> - success = process_inode_data(dip, TYP_SYMLINK);
> + rval = process_inode_data(dip, TYP_SYMLINK);
> if (dip->di_format == XFS_DINODE_FMT_LOCAL)
> need_new_crc = 1;
> break;
> case S_IFREG:
> - success = process_inode_data(dip, TYP_DATA);
> + rval = process_inode_data(dip, TYP_DATA);
> break;
> case S_IFIFO:
> case S_IFCHR:
> case S_IFBLK:
> case S_IFSOCK:
> - success = process_dev_inode(dip);
> + process_dev_inode(dip);
> need_new_crc = 1;
> break;
> default:
> break;
> }
> nametable_clear();
> + if (!rval)
> + goto done;
>
> /* copy extended attributes if they exist and forkoff is valid */
> - if (success && XFS_DFORK_DSIZE(dip, mp) < XFS_LITINO(mp)) {
> + if (XFS_DFORK_DSIZE(dip, mp) < XFS_LITINO(mp)) {
> attr_data.remote_val_count = 0;
> switch (dip->di_aformat) {
> case XFS_DINODE_FMT_LOCAL:
> @@ -2425,11 +2424,11 @@ process_inode(
> break;
>
> case XFS_DINODE_FMT_EXTENTS:
> - success = process_exinode(dip, TYP_ATTR);
> + rval = process_exinode(dip, TYP_ATTR);
> break;
>
> case XFS_DINODE_FMT_BTREE:
> - success = process_btinode(dip, TYP_ATTR);
> + rval = process_btinode(dip, TYP_ATTR);
> break;
> }
> nametable_clear();
> @@ -2442,7 +2441,8 @@ done:
>
> if (crc_was_ok && need_new_crc)
> libxfs_dinode_calc_crc(mp, dip);
> - return success;
> +
> + return rval;
> }
>
> static uint32_t inodes_copied;
> @@ -2541,7 +2541,7 @@ copy_inode_chunk(
>
> /* process_inode handles free inodes, too */
> if (!process_inode(agno, agino + ioff + i, dip,
> - XFS_INOBT_IS_FREE_DISK(rp, ioff + i)))
> + XFS_INOBT_IS_FREE_DISK(rp, ioff + i)))
> goto pop_out;
>
> inodes_copied++;
> @@ -2800,7 +2800,7 @@ copy_ino(
> xfs_agblock_t agbno;
> xfs_agino_t agino;
> int offset;
> - int rval = 0;
> + int rval = 1;
>
> if (ino == 0 || ino == NULLFSINO)
> return 1;