This adds a new "crc" command to xfs_db for CRC-enabled filesystems.
If a structure has a CRC field, we can validate it, invalidate/corrupt
it, or revalidate/rewrite it:
xfs_db> sb 0
xfs_db> crc -v
crc = 0x796c814f (correct)
xfs_db> crc -i
Metadata CRC error detected at block 0x0/0x200
crc = 0x796c8150 (bad)
xfs_db> crc -r
crc = 0x796c814f (correct)
(-i and -r require "expert" write-capable mode)
This requires temporarily replacing the write verifier with
a dummy which won't recalculate the CRC on the way to disk.
It also required me to write a new flist function, which is
totally foreign to me, so hopefully done right - but it seems
to work here.
Signed-off-by: Eric Sandeen <sandeen@xxxxxxxxxx>
---
I found this very useful when working with a filesystem image
which was consistent except for a corrupt CRC; the ability to
rewrite the correct CRCs and run repair to validate the fs was
very handy...
V2: Fix whitespace damage, clarify write_cur() changes
a bit w/ code & comments.
V3: Be a bit more verbose with command output
V4: Rebase patch to current tree
diff --git a/db/Makefile b/db/Makefile
index 8260da3..ba4b1a8 100644
--- a/db/Makefile
+++ b/db/Makefile
@@ -8,7 +8,7 @@ include $(TOPDIR)/include/builddefs
LTCOMMAND = xfs_db
HFILES = addr.h agf.h agfl.h agi.h attr.h attrshort.h bit.h block.h bmap.h \
- btblock.h bmroot.h check.h command.h convert.h debug.h \
+ btblock.h bmroot.h check.h command.h convert.h crc.h debug.h \
dir2.h dir2sf.h dquot.h echo.h faddr.h field.h \
flist.h fprint.h frag.h freesp.h hash.h help.h init.h inode.h input.h \
io.h logformat.h malloc.h metadump.h output.h print.h quit.h sb.h \
diff --git a/db/command.c b/db/command.c
index 3c17a1e..1848d64 100644
--- a/db/command.c
+++ b/db/command.c
@@ -49,6 +49,7 @@
#include "write.h"
#include "malloc.h"
#include "dquot.h"
+#include "crc.h"
cmdinfo_t *cmdtab;
int ncmds;
@@ -124,6 +125,7 @@ init_commands(void)
bmap_init();
check_init();
convert_init();
+ crc_init();
debug_init();
echo_init();
frag_init();
diff --git a/db/flist.c b/db/flist.c
index 84065a2..2530baf 100644
--- a/db/flist.c
+++ b/db/flist.c
@@ -411,6 +411,40 @@ flist_split(
return v;
}
+/*
+ * Given a set of fields, scan for a field of the given type.
+ * Return an flist leading to the first found field
+ * of that type.
+ * Return NULL if no field of the given type is found.
+ */
+flist_t *
+flist_find_ftyp(
+ const field_t *fields,
+ fldt_t type)
+{
+ flist_t *fl;
+ const field_t *f;
+ const ftattr_t *fa;
+
+ for (f = fields; f->name; f++) {
+ fl = flist_make(f->name);
+ fl->fld = f;
+ if (f->ftyp == type)
+ return fl;
+ fa = &ftattrtab[f->ftyp];
+ if (fa->subfld) {
+ flist_t *nfl;
+ nfl = flist_find_ftyp(fa->subfld, type);
+ if (nfl) {
+ fl->child = nfl;
+ return fl;
+ }
+ }
+ flist_free(fl);
+ }
+ return NULL;
+}
+
static void
ftok_free(
ftok_t *ft)
diff --git a/db/flist.h b/db/flist.h
index 5c9fba0..3f4b312 100644
--- a/db/flist.h
+++ b/db/flist.h
@@ -37,3 +37,4 @@ extern int flist_parse(const struct field *fields, flist_t
*fl, void *obj,
int startoff);
extern void flist_print(flist_t *fl);
extern flist_t *flist_scan(char *name);
+extern flist_t *flist_find_ftyp(const field_t *fields, fldt_t type);
diff --git a/db/io.c b/db/io.c
index 91cab12..56b4414 100644
--- a/db/io.c
+++ b/db/io.c
@@ -27,6 +27,7 @@
#include "output.h"
#include "init.h"
#include "malloc.h"
+#include "crc.h"
static int pop_f(int argc, char **argv);
static void pop_help(void);
@@ -473,12 +474,14 @@ xfs_verify_recalc_crc(
void
write_cur(void)
{
+ int skip_crc = (iocur_top->bp->b_ops->verify_write == xfs_dummy_verify);
+
if (iocur_sp < 0) {
dbprintf(_("nothing to write\n"));
return;
}
- if (xfs_sb_version_hascrc(&mp->m_sb) && iocur_top->ino_buf) {
+ if (xfs_sb_version_hascrc(&mp->m_sb) && iocur_top->ino_buf &&
!skip_crc) {
libxfs_dinode_calc_crc(mp, iocur_top->data);
iocur_top->ino_crc_ok = 1;
}
@@ -489,6 +492,19 @@ write_cur(void)
write_cur_bbs();
else
write_cur_buf();
+
+ /* If we didn't write the crc automatically, re-check validity */
+ if (iocur_top->ino_buf && skip_crc) {
+ xfs_dinode_t *dip;
+ xfs_ino_t ino;
+
+ dip = iocur_top->data;
+ ino = iocur_top->ino;
+ iocur_top->ino_crc_ok = xfs_verify_cksum((char *)dip,
+ mp->m_sb.sb_inodesize,
+ XFS_DINODE_CRC_OFF);
+ }
+
}
void
diff --git a/db/write.h b/db/write.h
index 31e2665..664ddcc 100644
--- a/db/write.h
+++ b/db/write.h
@@ -20,5 +20,5 @@ struct field;
extern void write_init(void);
extern void write_block(const field_t *fields, int argc, char **argv);
-extern void write_string(const field_t *fields, int argc, char **argv);
extern void write_struct(const field_t *fields, int argc, char **argv);
+extern void write_string(const field_t *fields, int argc, char **argv);
diff --git a/man/man8/xfs_db.8 b/man/man8/xfs_db.8
index ff8f862..894a94e 100644
--- a/man/man8/xfs_db.8
+++ b/man/man8/xfs_db.8
@@ -87,16 +87,14 @@ or
.I filename
read-only. This option is required if the filesystem is mounted.
It is only necessary to omit this flag if a command that changes data
-.RB ( write ", " blocktrash )
+.RB ( write ", " blocktrash ", " crc )
is to be used.
.TP
.B \-x
Specifies expert mode.
This enables the
-.B write
-and
-.B blocktrash
-commands.
+.RB ( write ", " blocktrash ", " crc
+invalidate/revalidate) commands.
.TP
.B \-V
Prints the version number and exits.
@@ -422,6 +420,25 @@ conversions such as
.I agb
.BR fsblock .
.TP
+.B crc [\-i|\-r|\-v]
+Invalidates, revalidates, or validates the CRC (checksum)
+field of the current structure, if it has one.
+This command is available only on CRC-enabled filesystems.
+With no argument, validation is performed.
+Each command will display the resulting CRC value and state.
+.RS 1.0i
+.TP 0.4i
+.B \-i
+Invalidate the structure's CRC value (incrementing it by one),
+and write it to disk.
+.TP
+.B \-r
+Recalculate the current structure's correct CRC value, and write it to disk.
+.TP
+.B \-v
+Validate and display the current value and state of the structure's CRC.
+.RE
+.TP
.BI "daddr [" d ]
Set current address to the daddr (512 byte block) given by
.IR d .
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