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-rw-r--r--fs/cifs/file.c106
1 files changed, 60 insertions, 46 deletions
diff --git a/fs/cifs/file.c b/fs/cifs/file.c
index 253170dfa716..513adbc211d7 100644
--- a/fs/cifs/file.c
+++ b/fs/cifs/file.c
@@ -876,7 +876,7 @@ cifs_push_mandatory_locks(struct cifsFileInfo *cfile)
struct cifsLockInfo *li, *tmp;
struct cifs_tcon *tcon;
struct cifsInodeInfo *cinode = CIFS_I(cfile->dentry->d_inode);
- unsigned int num, max_num;
+ unsigned int num, max_num, max_buf;
LOCKING_ANDX_RANGE *buf, *cur;
int types[] = {LOCKING_ANDX_LARGE_FILES,
LOCKING_ANDX_SHARED_LOCK | LOCKING_ANDX_LARGE_FILES};
@@ -892,8 +892,19 @@ cifs_push_mandatory_locks(struct cifsFileInfo *cfile)
return rc;
}
- max_num = (tcon->ses->server->maxBuf - sizeof(struct smb_hdr)) /
- sizeof(LOCKING_ANDX_RANGE);
+ /*
+ * Accessing maxBuf is racy with cifs_reconnect - need to store value
+ * and check it for zero before using.
+ */
+ max_buf = tcon->ses->server->maxBuf;
+ if (!max_buf) {
+ mutex_unlock(&cinode->lock_mutex);
+ FreeXid(xid);
+ return -EINVAL;
+ }
+
+ max_num = (max_buf - sizeof(struct smb_hdr)) /
+ sizeof(LOCKING_ANDX_RANGE);
buf = kzalloc(max_num * sizeof(LOCKING_ANDX_RANGE), GFP_KERNEL);
if (!buf) {
mutex_unlock(&cinode->lock_mutex);
@@ -1218,7 +1229,7 @@ cifs_unlock_range(struct cifsFileInfo *cfile, struct file_lock *flock, int xid)
int types[] = {LOCKING_ANDX_LARGE_FILES,
LOCKING_ANDX_SHARED_LOCK | LOCKING_ANDX_LARGE_FILES};
unsigned int i;
- unsigned int max_num, num;
+ unsigned int max_num, num, max_buf;
LOCKING_ANDX_RANGE *buf, *cur;
struct cifs_tcon *tcon = tlink_tcon(cfile->tlink);
struct cifsInodeInfo *cinode = CIFS_I(cfile->dentry->d_inode);
@@ -1228,8 +1239,16 @@ cifs_unlock_range(struct cifsFileInfo *cfile, struct file_lock *flock, int xid)
INIT_LIST_HEAD(&tmp_llist);
- max_num = (tcon->ses->server->maxBuf - sizeof(struct smb_hdr)) /
- sizeof(LOCKING_ANDX_RANGE);
+ /*
+ * Accessing maxBuf is racy with cifs_reconnect - need to store value
+ * and check it for zero before using.
+ */
+ max_buf = tcon->ses->server->maxBuf;
+ if (!max_buf)
+ return -EINVAL;
+
+ max_num = (max_buf - sizeof(struct smb_hdr)) /
+ sizeof(LOCKING_ANDX_RANGE);
buf = kzalloc(max_num * sizeof(LOCKING_ANDX_RANGE), GFP_KERNEL);
if (!buf)
return -ENOMEM;
@@ -1247,46 +1266,7 @@ cifs_unlock_range(struct cifsFileInfo *cfile, struct file_lock *flock, int xid)
continue;
if (types[i] != li->type)
continue;
- if (!cinode->can_cache_brlcks) {
- cur->Pid = cpu_to_le16(li->pid);
- cur->LengthLow = cpu_to_le32((u32)li->length);
- cur->LengthHigh =
- cpu_to_le32((u32)(li->length>>32));
- cur->OffsetLow = cpu_to_le32((u32)li->offset);
- cur->OffsetHigh =
- cpu_to_le32((u32)(li->offset>>32));
- /*
- * We need to save a lock here to let us add
- * it again to the file's list if the unlock
- * range request fails on the server.
- */
- list_move(&li->llist, &tmp_llist);
- if (++num == max_num) {
- stored_rc = cifs_lockv(xid, tcon,
- cfile->netfid,
- li->type, num,
- 0, buf);
- if (stored_rc) {
- /*
- * We failed on the unlock range
- * request - add all locks from
- * the tmp list to the head of
- * the file's list.
- */
- cifs_move_llist(&tmp_llist,
- &cfile->llist);
- rc = stored_rc;
- } else
- /*
- * The unlock range request
- * succeed - free the tmp list.
- */
- cifs_free_llist(&tmp_llist);
- cur = buf;
- num = 0;
- } else
- cur++;
- } else {
+ if (cinode->can_cache_brlcks) {
/*
* We can cache brlock requests - simply remove
* a lock from the file's list.
@@ -1294,7 +1274,41 @@ cifs_unlock_range(struct cifsFileInfo *cfile, struct file_lock *flock, int xid)
list_del(&li->llist);
cifs_del_lock_waiters(li);
kfree(li);
+ continue;
}
+ cur->Pid = cpu_to_le16(li->pid);
+ cur->LengthLow = cpu_to_le32((u32)li->length);
+ cur->LengthHigh = cpu_to_le32((u32)(li->length>>32));
+ cur->OffsetLow = cpu_to_le32((u32)li->offset);
+ cur->OffsetHigh = cpu_to_le32((u32)(li->offset>>32));
+ /*
+ * We need to save a lock here to let us add it again to
+ * the file's list if the unlock range request fails on
+ * the server.
+ */
+ list_move(&li->llist, &tmp_llist);
+ if (++num == max_num) {
+ stored_rc = cifs_lockv(xid, tcon, cfile->netfid,
+ li->type, num, 0, buf);
+ if (stored_rc) {
+ /*
+ * We failed on the unlock range
+ * request - add all locks from the tmp
+ * list to the head of the file's list.
+ */
+ cifs_move_llist(&tmp_llist,
+ &cfile->llist);
+ rc = stored_rc;
+ } else
+ /*
+ * The unlock range request succeed -
+ * free the tmp list.
+ */
+ cifs_free_llist(&tmp_llist);
+ cur = buf;
+ num = 0;
+ } else
+ cur++;
}
if (num) {
stored_rc = cifs_lockv(xid, tcon, cfile->netfid,