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-rw-r--r--fs/btrfs/inode.c33
1 files changed, 25 insertions, 8 deletions
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index c72033ee6017..021694c08181 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -5170,14 +5170,31 @@ next:
}
/* Reached end of directory/root. Bump pos past the last item. */
- if (key_type == BTRFS_DIR_INDEX_KEY)
- /*
- * 32-bit glibc will use getdents64, but then strtol -
- * so the last number we can serve is this.
- */
- ctx->pos = 0x7fffffff;
- else
- ctx->pos++;
+ ctx->pos++;
+
+ /*
+ * Stop new entries from being returned after we return the last
+ * entry.
+ *
+ * New directory entries are assigned a strictly increasing
+ * offset. This means that new entries created during readdir
+ * are *guaranteed* to be seen in the future by that readdir.
+ * This has broken buggy programs which operate on names as
+ * they're returned by readdir. Until we re-use freed offsets
+ * we have this hack to stop new entries from being returned
+ * under the assumption that they'll never reach this huge
+ * offset.
+ *
+ * This is being careful not to overflow 32bit loff_t unless the
+ * last entry requires it because doing so has broken 32bit apps
+ * in the past.
+ */
+ if (key_type == BTRFS_DIR_INDEX_KEY) {
+ if (ctx->pos >= INT_MAX)
+ ctx->pos = LLONG_MAX;
+ else
+ ctx->pos = INT_MAX;
+ }
nopos:
ret = 0;
err: