Author: bdrewery
Date: Fri Mar 14 02:10:30 2014
New Revision: 263131
URL: http://svnweb.freebsd.org/changeset/base/263131
Log:
Cleanup redundant logic and add some comments to help explain how
it works in lieu of potentially less clear code.
Sponsored by: EMC / Isilon Storage Division
Discussed with: Russell Cattelan
Modified:
head/sys/fs/tmpfs/tmpfs_subr.c
Modified: head/sys/fs/tmpfs/tmpfs_subr.c
==============================================================================
--- head/sys/fs/tmpfs/tmpfs_subr.c Fri Mar 14 01:43:55 2014
(r263130)
+++ head/sys/fs/tmpfs/tmpfs_subr.c Fri Mar 14 02:10:30 2014
(r263131)
@@ -348,6 +348,9 @@ tmpfs_dirent_hash(const char *name, u_in
static __inline off_t
tmpfs_dirent_cookie(struct tmpfs_dirent *de)
{
+ if (de == NULL)
+ return (TMPFS_DIRCOOKIE_EOF);
+
MPASS(de->td_cookie >= TMPFS_DIRCOOKIE_MIN);
return (de->td_cookie);
@@ -1155,6 +1158,15 @@ tmpfs_dir_getdents(struct tmpfs_node *no
TMPFS_VALIDATE_DIR(node);
off = 0;
+
+ /*
+ * Lookup the node from the current offset. The starting offset of
+ * 0 will lookup both '.' and '..', and then the first real entry,
+ * or EOF if there are none. Then find all entries for the dir that
+ * fit into the buffer. Once no more entries are found (de == NULL),
+ * the offset is set to TMPFS_DIRCOOKIE_EOF, which will cause the next
+ * call to return 0.
+ */
switch (uio->uio_offset) {
case TMPFS_DIRCOOKIE_DOT:
error = tmpfs_dir_getdotdent(node, uio);
@@ -1168,12 +1180,10 @@ tmpfs_dir_getdents(struct tmpfs_node *no
if (error != 0)
return (error);
de = tmpfs_dir_first(node, &dc);
- if (de == NULL)
- uio->uio_offset = TMPFS_DIRCOOKIE_EOF;
- else
- uio->uio_offset = tmpfs_dirent_cookie(de);
+ uio->uio_offset = tmpfs_dirent_cookie(de);
if (cnt != 0)
cookies[(*ncookies)++] = off = uio->uio_offset;
+ /* EOF. */
if (de == NULL)
return (0);
break;
@@ -1252,10 +1262,7 @@ tmpfs_dir_getdents(struct tmpfs_node *no
if (error == 0) {
de = tmpfs_dir_next(node, &dc);
if (cnt != 0) {
- if (de == NULL)
- off = TMPFS_DIRCOOKIE_EOF;
- else
- off = tmpfs_dirent_cookie(de);
+ off = tmpfs_dirent_cookie(de);
MPASS(*ncookies < cnt);
cookies[(*ncookies)++] = off;
}
@@ -1263,12 +1270,8 @@ tmpfs_dir_getdents(struct tmpfs_node *no
} while (error == 0 && uio->uio_resid > 0 && de != NULL);
/* Update the offset and cache. */
- if (cnt == 0) {
- if (de == NULL)
- off = TMPFS_DIRCOOKIE_EOF;
- else
- off = tmpfs_dirent_cookie(de);
- }
+ if (cnt == 0)
+ off = tmpfs_dirent_cookie(de);
uio->uio_offset = off;
node->tn_dir.tn_readdir_lastn = off;
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