[PATCH] metadump: handle corruption errors without aborting

Dave Chinner
2022-02-02T07:42:46Z

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;