zfsonlinux/zfs — pull request #2988 by nedbass (2014-12-23 00:59:22+00:00)
Title: Document zfs_flags module parameter

Add a table describing the debugging flags that can be set in the zfs_flags
module parameter. Also change the module_param type to 'uint' so users aren't
shown a negative value. The updated man page text is reproduced below for
convenience.

```
zfs_flags (int)

Set additional debugging flags. The following flags may be
bitwise-or'd together. The ZFS_DEBUG_DBUF_VERIFY and ZFS_DEBUG_DNODE flags are
ignored unless ZFS was built with debugging enabled.

Value Symbolic Name Description
1 ZFS_DEBUG_DPRINTF Enable dprintf entries in the debug log
2 ZFS_DEBUG_DBUF_VERIFY Enable extra dbuf verifications
4 ZFS_DEBUG_DNODE_VERIFY Enable extra dnode verifications
8 ZFS_DEBUG_SNAPNAMES Enable snapshot name verification
16 ZFS_DEBUG_MODIFY Check for illegally modified ARC buffers
32 ZFS_DEBUG_SPA Enable spa_dbgmsg entries in the debug log
64 ZFS_DEBUG_ZIO_FREE Enable verification of block frees
128 ZFS_DEBUG_HISTOGRAM_VERIFY Enable extra spacemap histogram verifications

Default value: 0.
```
Signed-off-by: Ned Bass