libext2fs: rewind extent pointer when totally deleting an extent
During a punch operation, if we decide to delete an extent out of the
extent tree, the subsequent extents are moved on top of the current
extent (that is to say, they're memmmove'd down one slot). Therefore
it is not correct to advance to the next leaf because that means we
miss half the extents in the range! Rereading the current pointer
should be fine.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
diff --git a/lib/ext2fs/punch.c b/lib/ext2fs/punch.c
index b53653a..11c7668 100644
--- a/lib/ext2fs/punch.c
+++ b/lib/ext2fs/punch.c
@@ -186,6 +186,7 @@
blk64_t free_start, next;
__u32 free_count, newlen;
int freed = 0;
+ int op;
retval = ext2fs_extent_open2(fs, ino, inode, &handle);
if (retval)
@@ -195,6 +196,7 @@
if (retval)
goto errout;
while (1) {
+ op = EXT2_EXTENT_NEXT_LEAF;
dbg_print_extent("main loop", &extent);
next = extent.e_lblk + extent.e_len;
dbg_printf("start %llu, end %llu, next %llu\n",
@@ -256,8 +258,23 @@
dbg_print_extent("replacing", &extent);
retval = ext2fs_extent_replace(handle, 0, &extent);
} else {
+ struct ext2fs_extent newex;
dbg_printf("deleting current extent%s\n", "");
retval = ext2fs_extent_delete(handle, 0);
+ if (retval)
+ goto errout;
+ /*
+ * We just moved the next extent into the current
+ * extent's position, so re-read the extent next time.
+ */
+ retval = ext2fs_extent_get(handle,
+ EXT2_EXTENT_PREV_LEAF,
+ &newex);
+ /* Can't go back? Just reread current. */
+ if (retval == EXT2_ET_EXTENT_NO_PREV) {
+ retval = 0;
+ op = EXT2_EXTENT_CURRENT;
+ }
}
if (retval)
goto errout;
@@ -268,9 +285,10 @@
freed++;
}
next_extent:
- retval = ext2fs_extent_get(handle, EXT2_EXTENT_NEXT_LEAF,
+ retval = ext2fs_extent_get(handle, op,
&extent);
- if (retval == EXT2_ET_EXTENT_NO_NEXT)
+ if (retval == EXT2_ET_EXTENT_NO_NEXT ||
+ retval == EXT2_ET_NO_CURRENT_NODE)
break;
if (retval)
goto errout;