orangefs: support llseek on directories

This and the previous commit fix xfstests generic/257.

Signed-off-by: Martin Brandenburg <martin@omnibond.com>
Signed-off-by: Mike Marshall <hubcap@omnibond.com>

diff --git a/fs/orangefs/dir.c b/fs/orangefs/dir.c
index cf0ebb06b84e9e1c09091834fe9cff6375f2840f..9744fb3ad144f1ee74dc7b0a028fc17d25a14c36 100644 (file)
--- a/fs/orangefs/dir.c
+++ b/fs/orangefs/dir.c
@@ -21,7 +21,7 @@
 struct orangefs_dir {
        __u64 token;
        void *directory;
-       size_t i, len;
+       size_t len;
        int error;
 };
 
@@ -132,35 +132,40 @@ static int orangefs_dir_fill(struct orangefs_inode_s *oi,
 {
        struct orangefs_khandle *khandle;
        __u32 *len, padlen;
+       loff_t i;
        char *s;
-       while (od->i < od->len) {
-               if (od->len < od->i + sizeof *len)
+       i = ctx->pos - 2;
+       while (i < od->len) {
+               if (od->len < i + sizeof *len)
                        goto eio;
-               len = od->directory + od->i;
+               len = od->directory + i;
                /*
                 * len is the size of the string itself.  padlen is the
                 * total size of the encoded string.
                 */
                padlen = (sizeof *len + *len + 1) +
                    (4 - (sizeof *len + *len + 1)%8)%8;
-               if (od->len < od->i + padlen + sizeof *khandle)
+               if (od->len < i + padlen + sizeof *khandle)
                        goto eio;
-               s = od->directory + od->i + sizeof *len;
+               s = od->directory + i + sizeof *len;
                if (s[*len] != 0)
                        goto eio;
-               khandle = od->directory + od->i + padlen;
+               khandle = od->directory + i + padlen;
 
                if (!dir_emit(ctx, s, *len,
                    orangefs_khandle_to_ino(khandle), DT_UNKNOWN))
                        return 0;
-               od->i += padlen + sizeof *khandle;
-               od->i = od->i + (8 - od->i%8)%8;
-               ctx->pos = 2 + od->i;
+               i += padlen + sizeof *khandle;
+               i = i + (8 - i%8)%8;
+               ctx->pos = i + 2;
        }
-       BUG_ON(od->i > od->len);
+       BUG_ON(i > od->len);
        return 0;
 eio:
-       gossip_err("orangefs_dir_fill: userspace returns corrupt data\n");
+       /*
+        * Here either data from userspace is corrupt or the application
+        * has sought to an invalid location.
+        */
        od->error = -EIO;
        return -EIO;
 }
@@ -193,12 +198,29 @@ static int orangefs_dir_iterate(struct file *file,
 
        r = 0;
 
-       if (od->i < od->len) {
+       /*
+        * Must read more if the user has sought past what has been read
+        * so far.  Stop a user who has sought past the end.
+        */
+       while (od->token != ORANGEFS_READDIR_END && ctx->pos - 2 >
+           od->len) {
+               r = orangefs_dir_more(oi, od, dentry);
+               if (r)
+                       return r;
+       }
+       if (od->token == ORANGEFS_READDIR_END && ctx->pos - 2 >
+           od->len) {
+               return -EIO;
+       }
+
+       /* Then try to fill if there's any left in the buffer. */
+       if (ctx->pos - 2 < od->len) {
                r = orangefs_dir_fill(oi, od, dentry, ctx);
                if (r)
                        return r;
        }
 
+       /* Finally get some more and try to fill. */
        if (od->token != ORANGEFS_READDIR_END) {
                r = orangefs_dir_more(oi, od, dentry);
                if (r)
@@ -227,7 +249,6 @@ static int orangefs_dir_open(struct inode *inode, struct file *file)
                kfree(file->private_data);
                return -ENOMEM;
        }
-       od->i = 0;
        od->len = 0;
        od->error = 0;
        return 0;
@@ -243,6 +264,7 @@ static int orangefs_dir_release(struct inode *inode, struct file *file)
 }
 
 const struct file_operations orangefs_dir_operations = {
+       .llseek = default_llseek,
        .read = generic_read_dir,
        .iterate = orangefs_dir_iterate,
        .open = orangefs_dir_open,