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-rw-r--r--fs/qnx4/dir.c69
1 files changed, 52 insertions, 17 deletions
diff --git a/fs/qnx4/dir.c b/fs/qnx4/dir.c
index a6ee23aadd28..66645a5a35f3 100644
--- a/fs/qnx4/dir.c
+++ b/fs/qnx4/dir.c
@@ -15,13 +15,48 @@
#include <linux/buffer_head.h>
#include "qnx4.h"
+/*
+ * A qnx4 directory entry is an inode entry or link info
+ * depending on the status field in the last byte. The
+ * first byte is where the name start either way, and a
+ * zero means it's empty.
+ *
+ * Also, due to a bug in gcc, we don't want to use the
+ * real (differently sized) name arrays in the inode and
+ * link entries, but always the 'de_name[]' one in the
+ * fake struct entry.
+ *
+ * See
+ *
+ * https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99578#c6
+ *
+ * for details, but basically gcc will take the size of the
+ * 'name' array from one of the used union entries randomly.
+ *
+ * This use of 'de_name[]' (48 bytes) avoids the false positive
+ * warnings that would happen if gcc decides to use 'inode.di_name'
+ * (16 bytes) even when the pointer and size were to come from
+ * 'link.dl_name' (48 bytes).
+ *
+ * In all cases the actual name pointer itself is the same, it's
+ * only the gcc internal 'what is the size of this field' logic
+ * that can get confused.
+ */
+union qnx4_directory_entry {
+ struct {
+ const char de_name[48];
+ u8 de_pad[15];
+ u8 de_status;
+ };
+ struct qnx4_inode_entry inode;
+ struct qnx4_link_info link;
+};
+
static int qnx4_readdir(struct file *file, struct dir_context *ctx)
{
struct inode *inode = file_inode(file);
unsigned int offset;
struct buffer_head *bh;
- struct qnx4_inode_entry *de;
- struct qnx4_link_info *le;
unsigned long blknum;
int ix, ino;
int size;
@@ -38,27 +73,27 @@ static int qnx4_readdir(struct file *file, struct dir_context *ctx)
}
ix = (ctx->pos >> QNX4_DIR_ENTRY_SIZE_BITS) % QNX4_INODES_PER_BLOCK;
for (; ix < QNX4_INODES_PER_BLOCK; ix++, ctx->pos += QNX4_DIR_ENTRY_SIZE) {
+ union qnx4_directory_entry *de;
+
offset = ix * QNX4_DIR_ENTRY_SIZE;
- de = (struct qnx4_inode_entry *) (bh->b_data + offset);
- if (!de->di_fname[0])
+ de = (union qnx4_directory_entry *) (bh->b_data + offset);
+
+ if (!de->de_name[0])
continue;
- if (!(de->di_status & (QNX4_FILE_USED|QNX4_FILE_LINK)))
+ if (!(de->de_status & (QNX4_FILE_USED|QNX4_FILE_LINK)))
continue;
- if (!(de->di_status & QNX4_FILE_LINK))
- size = QNX4_SHORT_NAME_MAX;
- else
- size = QNX4_NAME_MAX;
- size = strnlen(de->di_fname, size);
- QNX4DEBUG((KERN_INFO "qnx4_readdir:%.*s\n", size, de->di_fname));
- if (!(de->di_status & QNX4_FILE_LINK))
+ if (!(de->de_status & QNX4_FILE_LINK)) {
+ size = sizeof(de->inode.di_fname);
ino = blknum * QNX4_INODES_PER_BLOCK + ix - 1;
- else {
- le = (struct qnx4_link_info*)de;
- ino = ( le32_to_cpu(le->dl_inode_blk) - 1 ) *
+ } else {
+ size = sizeof(de->link.dl_fname);
+ ino = ( le32_to_cpu(de->link.dl_inode_blk) - 1 ) *
QNX4_INODES_PER_BLOCK +
- le->dl_inode_ndx;
+ de->link.dl_inode_ndx;
}
- if (!dir_emit(ctx, de->di_fname, size, ino, DT_UNKNOWN)) {
+ size = strnlen(de->de_name, size);
+ QNX4DEBUG((KERN_INFO "qnx4_readdir:%.*s\n", size, name));
+ if (!dir_emit(ctx, de->de_name, size, ino, DT_UNKNOWN)) {
brelse(bh);
return 0;
}