[PATCH 8/8] xfs_repair: support more than INT_MAX block maps

Darrick J. Wong
2023-12-31T22:10:23Z

Now that it's possible to have more than INT_MAX block mappings attached
to a file fork, expand the counters used by this data structure so that
it can support all possible block mappings.

Note that in practice we're still never going to exceed 4 billion
extents because the previous patch switched off the block mappings for
regular files. This is still twice as much as memory as previous, but
it's not totally unconstrained. Hopefully few people bloat the xattr
structures that large.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
---
repair/bmap.c | 26 ++++++++++++++------------
repair/bmap.h | 9 ++++-----
repair/dinode.c | 2 +-
repair/dir2.c | 2 +-
4 files changed, 20 insertions(+), 19 deletions(-)

diff --git a/repair/bmap.c b/repair/bmap.c
index cd1a8b07b30..9ae28686107 100644
--- a/repair/bmap.c
+++ b/repair/bmap.c
@@ -34,8 +34,9 @@ blkmap_alloc(

if (nex < 1)
nex = 1;
+ nex = min(nex, XFS_MAX_EXTCNT_DATA_FORK_LARGE);

-#if (BITS_PER_LONG == 32) /* on 64-bit platforms this is never true */
+#ifdef BLKMAP_NEXTS_MAX
if (nex > BLKMAP_NEXTS_MAX) {
do_warn(
_("Number of extents requested in blkmap_alloc (%llu) overflows 32 bits.\n"
@@ -115,7 +116,7 @@ blkmap_get(
xfs_fileoff_t o)
{
bmap_ext_t *ext = blkmap->exts;
- int i;
+ xfs_extnum_t i;

for (i = 0; i < blkmap->nexts; i++, ext++) {
if (o >= ext->startoff && o < ext->startoff + ext->blockcount)
@@ -137,7 +138,7 @@ blkmap_getn(
{
bmap_ext_t *bmp = NULL;
bmap_ext_t *ext;
- int i;
+ xfs_extnum_t i;
int nex;

if (nb == 1) {
@@ -233,7 +234,7 @@ xfs_fileoff_t
blkmap_next_off(
blkmap_t *blkmap,
xfs_fileoff_t o,
- int *t)
+ xfs_extnum_t *t)
{
bmap_ext_t *ext;

@@ -263,7 +264,7 @@ blkmap_grow(
{
pthread_key_t key = dblkmap_key;
blkmap_t *new_blkmap;
- int new_naexts;
+ xfs_extnum_t new_naexts;

/* reduce the number of reallocations for large files */
if (blkmap->naexts < 1000)
@@ -278,20 +279,21 @@ blkmap_grow(
ASSERT(pthread_getspecific(key) == blkmap);
}

-#if (BITS_PER_LONG == 32) /* on 64-bit platforms this is never true */
+#ifdef BLKMAP_NEXTS_MAX
if (new_naexts > BLKMAP_NEXTS_MAX) {
do_error(
- _("Number of extents requested in blkmap_grow (%d) overflows 32 bits.\n"
+ _("Number of extents requested in blkmap_grow (%llu) overflows 32 bits.\n"
"You need a 64 bit system to repair this filesystem.\n"),
- new_naexts);
+ (unsigned long long)new_naexts);
return NULL;
}
#endif
- if (new_naexts <= 0) {
+ if (new_naexts > XFS_MAX_EXTCNT_DATA_FORK_LARGE) {
do_error(
- _("Number of extents requested in blkmap_grow (%d) overflowed the\n"
- "maximum number of supported extents (%d).\n"),
- new_naexts, BLKMAP_NEXTS_MAX);
+ _("Number of extents requested in blkmap_grow (%llu) overflowed the\n"
+ "maximum number of supported extents (%llu).\n"),
+ (unsigned long long)new_naexts,
+ (unsigned long long)XFS_MAX_EXTCNT_DATA_FORK_LARGE);
return NULL;
}

diff --git a/repair/bmap.h b/repair/bmap.h
index 4b588df8c86..3d6be94441c 100644
--- a/repair/bmap.h
+++ b/repair/bmap.h
@@ -20,8 +20,8 @@ typedef struct bmap_ext {
* Block map.
*/
typedef struct blkmap {
- int naexts;
- int nexts;
+ xfs_extnum_t naexts;
+ xfs_extnum_t nexts;
bmap_ext_t exts[1];
} blkmap_t;

@@ -37,8 +37,6 @@ typedef struct blkmap {
*/
#if BITS_PER_LONG == 32
#define BLKMAP_NEXTS_MAX ((INT_MAX / sizeof(bmap_ext_t)) - 1)
-#else
-#define BLKMAP_NEXTS_MAX INT_MAX
#endif

extern pthread_key_t dblkmap_key;
@@ -56,6 +54,7 @@ int blkmap_getn(blkmap_t *blkmap, xfs_fileoff_t o,
xfs_filblks_t nb, bmap_ext_t **bmpp,
bmap_ext_t *bmpp_single);
xfs_fileoff_t blkmap_last_off(blkmap_t *blkmap);
-xfs_fileoff_t blkmap_next_off(blkmap_t *blkmap, xfs_fileoff_t o, int *t);
+xfs_fileoff_t blkmap_next_off(blkmap_t *blkmap, xfs_fileoff_t o,
+ xfs_extnum_t *t);

#endif /* _XFS_REPAIR_BMAP_H */
diff --git a/repair/dinode.c b/repair/dinode.c
index f2961275cd1..629440fe6de 100644
--- a/repair/dinode.c
+++ b/repair/dinode.c
@@ -1136,7 +1136,7 @@ process_quota_inode(
xfs_dqid_t dqid;
xfs_fileoff_t qbno;
int i;
- int t = 0;
+ xfs_extnum_t t = 0;
int error;

switch (ino_type) {
diff --git a/repair/dir2.c b/repair/dir2.c
index 022b61b885f..e46ae9ae46f 100644
--- a/repair/dir2.c
+++ b/repair/dir2.c
@@ -1327,7 +1327,7 @@ process_leaf_node_dir2(
int i;
xfs_fileoff_t ndbno;
int nex;
- int t;
+ xfs_extnum_t t;
bmap_ext_t lbmp;
int dirty = 0;