LOOKUP_CREATE and LOOKUP_RENAME_TARGET can be set only on the last step

[firefly-linux-kernel-4.4.55.git] / fs / cifs / dir.c

diff --git a/fs/cifs/dir.c b/fs/cifs/dir.c
index 81914df47ef1612c1ab742d228503bbf5e598046..251c2ca569d3a2b15dd63f90261ccd149120794f 100644 (file)
--- a/fs/cifs/dir.c
+++ b/fs/cifs/dir.c
@@ -55,6 +55,7 @@ build_path_from_dentry(struct dentry *direntry)
        char dirsep;
        struct cifs_sb_info *cifs_sb = CIFS_SB(direntry->d_sb);
        struct cifs_tcon *tcon = cifs_sb_master_tcon(cifs_sb);
+       unsigned seq;
 
        if (direntry == NULL)
                return NULL;  /* not much we can do if dentry is freed and
@@ -68,22 +69,29 @@ build_path_from_dentry(struct dentry *direntry)
                dfsplen = 0;
 cifs_bp_rename_retry:
        namelen = dfsplen;
+       seq = read_seqbegin(&rename_lock);
+       rcu_read_lock();
        for (temp = direntry; !IS_ROOT(temp);) {
                namelen += (1 + temp->d_name.len);
                temp = temp->d_parent;
                if (temp == NULL) {
                        cERROR(1, "corrupt dentry");
+                       rcu_read_unlock();
                        return NULL;
                }
        }
+       rcu_read_unlock();
 
        full_path = kmalloc(namelen+1, GFP_KERNEL);
        if (full_path == NULL)
                return full_path;
        full_path[namelen] = 0; /* trailing null */
+       rcu_read_lock();
        for (temp = direntry; !IS_ROOT(temp);) {
+               spin_lock(&temp->d_lock);
                namelen -= 1 + temp->d_name.len;
                if (namelen < 0) {
+                       spin_unlock(&temp->d_lock);
                        break;
                } else {
                        full_path[namelen] = dirsep;
@@ -91,14 +99,17 @@ cifs_bp_rename_retry:
                                temp->d_name.len);
                        cFYI(0, "name: %s", full_path + namelen);
                }
+               spin_unlock(&temp->d_lock);
                temp = temp->d_parent;
                if (temp == NULL) {
                        cERROR(1, "corrupt dentry");
+                       rcu_read_unlock();
                        kfree(full_path);
                        return NULL;
                }
        }
-       if (namelen != dfsplen) {
+       rcu_read_unlock();
+       if (namelen != dfsplen || read_seqretry(&rename_lock, seq)) {
                cERROR(1, "did not end path lookup where expected namelen is %d",
                        namelen);
                /* presumably this is only possible if racing with a rename
@@ -168,7 +179,7 @@ cifs_create(struct inode *inode, struct dentry *direntry, int mode,
        if (oplockEnabled)
                oplock = REQ_OPLOCK;
 
-       if (nd && (nd->flags & LOOKUP_OPEN))
+       if (nd)
                oflags = nd->intent.open.file->f_flags;
        else
                oflags = O_RDONLY | O_CREAT;
@@ -203,7 +214,7 @@ cifs_create(struct inode *inode, struct dentry *direntry, int mode,
                   which should be rare for path not covered on files) */
        }
 
-       if (nd && (nd->flags & LOOKUP_OPEN)) {
+       if (nd) {
                /* if the file is going to stay open, then we
                   need to set the desired access properly */
                desiredAccess = 0;
@@ -317,7 +328,7 @@ cifs_create_set_dentry:
        else
                cFYI(1, "Create worked, get_inode_info failed rc = %d", rc);
 
-       if (newinode && nd && (nd->flags & LOOKUP_OPEN)) {
+       if (newinode && nd) {
                struct cifsFileInfo *pfile_info;
                struct file *filp;
 
@@ -652,10 +663,8 @@ cifs_d_revalidate(struct dentry *direntry, struct nameidata *nd)
         * case sensitive name which is specified by user if this is
         * for creation.
         */
-       if (!(nd->flags & (LOOKUP_CONTINUE | LOOKUP_PARENT))) {
-               if (nd->flags & (LOOKUP_CREATE | LOOKUP_RENAME_TARGET))
-                       return 0;
-       }
+       if (nd->flags & (LOOKUP_CREATE | LOOKUP_RENAME_TARGET))
+               return 0;
 
        if (time_after(jiffies, direntry->d_time + HZ) || !lookupCacheEnabled)
                return 0;