Merge pull request #240 from trapexit/readme

update readme with minfreespace and readonly details

README.md

@@ -74,16 +74,18 @@ All policies when used to create will ignore drives which are mounted readonly.
 | search   | access, getattr, getxattr, ioctl, listxattr, open, readlink |
 | N/A      | fallocate, fgetattr, fsync, ftruncate, ioctl, read, readdir, release, statfs, write |
 
-**ioctl** behaves differently if its acting on a directory. It'll use the **getattr** policy to find and open the directory before issuing the **ioctl**. In other cases where something may be searched (to confirm a directory exists across all source mounts) then **getattr** will be used.
+Due to FUSE limitations **ioctl** behaves differently if its acting on a directory. It'll use the **getattr** policy to find and open the directory before issuing the **ioctl**. In other cases where something may be searched (to confirm a directory exists across all source mounts) then **getattr** will be used.
 
 #### Policy descriptions ####
 
+Generally speaking most policies when called to create will filter out drives which are readonly or have less than `minfreespace`.
+
 | Policy | Description |
 |--------------|-------------|
-| all | Applies action to all found. For searches it will behave like first found **ff**. For `create` functions it will only apply to `mkdir`, `mkdnod`, and `symlink`. |
-| eplfs (existing path, least free space) | If the path exists on multiple drives use the one with the least free space and is greater than **minfreespace**. Falls back to **lfs**. |
-| epmfs (existing path, most free space) | If the path exists on multiple drives use the one with the most free space and is greater than **minfreespace**. Falls back to **mfs**. |
-| erofs | Exclusively return `-1` with `errno` set to EROFS. By setting `create` functions to this you can in effect turn the filesystem readonly. |
+| all | Search category: acts like **ff**. Action category: apply to all found. Create category: for **mkdir**, **mknod**, and **symlink** perform on all read/write drives with **minfreespace**. **create** filters the same way but acts like **ff**. |
+| eplfs (existing path, least free space) | If the path exists on multiple drives use the one with the least free space. Falls back to **lfs**. |
+| epmfs (existing path, most free space) | If the path exists on multiple drives use the one with the most free space. Falls back to **mfs**. |
+| erofs | Exclusively return **-1** with **errno** set to **EROFS**. By setting **create** functions to this you can in effect turn the filesystem readonly. |
 | ff (first found) | Given the order of the drives, as defined at mount time or when configured via xattr interface, act on the first one found. |
 | fwfs (first with free space) | Pick the first drive which has at least **minfreespace**. Falls back to **mfs**. |
 | lfs (least free space) | Pick the drive with the least available free space but more than **minfreespace**. Falls back to **mfs**. |

man/mergerfs.1

@@ -153,13 +153,17 @@ statfs, write
 T}
 .TE
 .PP
-\f[B]ioctl\f[] behaves differently if its acting on a directory.
+Due to FUSE limitations \f[B]ioctl\f[] behaves differently if its acting
+on a directory.
 It\[aq]ll use the \f[B]getattr\f[] policy to find and open the directory
 before issuing the \f[B]ioctl\f[].
 In other cases where something may be searched (to confirm a directory
 exists across all source mounts) then \f[B]getattr\f[] will be used.
 .SS Policy descriptions
 .PP
+Generally speaking most policies when called to create will filter out
+drives which are readonly or have less than \f[C]minfreespace\f[].
+.PP
 .TS
 tab(@);
 l l.
@@ -172,30 +176,33 @@ _
 T{
 all
 T}@T{
-Applies action to all found.
-For searches it will behave like first found \f[B]ff\f[].
-For \f[C]create\f[] functions it will only apply to \f[C]mkdir\f[],
-\f[C]mkdnod\f[], and \f[C]symlink\f[].
+Search category: acts like \f[B]ff\f[].
+Action category: apply to all found.
+Create category: for \f[B]mkdir\f[], \f[B]mknod\f[], and
+\f[B]symlink\f[] perform on all read/write drives with
+\f[B]minfreespace\f[].
+\f[B]create\f[] filters the same way but acts like \f[B]ff\f[].
 T}
 T{
 eplfs (existing path, least free space)
 T}@T{
 If the path exists on multiple drives use the one with the least free
-space and is greater than \f[B]minfreespace\f[].
+space.
 Falls back to \f[B]lfs\f[].
 T}
 T{
 epmfs (existing path, most free space)
 T}@T{
 If the path exists on multiple drives use the one with the most free
-space and is greater than \f[B]minfreespace\f[].
+space.
 Falls back to \f[B]mfs\f[].
 T}
 T{
 erofs
 T}@T{
-Exclusively return \f[C]\-1\f[] with \f[C]errno\f[] set to EROFS.
-By setting \f[C]create\f[] functions to this you can in effect turn the
+Exclusively return \f[B]\-1\f[] with \f[B]errno\f[] set to
+\f[B]EROFS\f[].
+By setting \f[B]create\f[] functions to this you can in effect turn the
 filesystem readonly.
 T}
 T{