Merge pull request #1447 from trapexit/branchcfg

Improve mount waiting + misc doc improvements

mkdocs/docs/config/branches.md

@@ -1,18 +1,20 @@
 # branches
 
-The 'branches' argument is a colon (':') delimited list of paths to be
+The `branches` argument is a colon (':') delimited list of paths to be
 pooled together. It does not matter if the paths are on the same or
-different filesystems nor does it matter the filesystem type (within
-reason). Used and available space will not be duplicated for paths on
-the same filesystem and any features which aren't supported by the
-underlying filesystem (such as file attributes or extended attributes)
-will return the appropriate errors.
+different filesystems nor does it matter [the filesystem
+type](../faq/compatibility_and_integration.md/#what-filesystems-can-be-used-as-branches)
+(within reason). Used and available space metrics will not be
+duplicated for paths on the same filesystem and any features which
+aren't supported by the underlying filesystem (such as file attributes
+or extended attributes) will return the appropriate errors.
 
-Branches currently have two options which can be set. A type which
-impacts whether or not the branch is included in a policy calculation
-and a individual minfreespace value. The values are set by prepending
-an `=` at the end of a branch designation and using commas as
-delimiters. Example: `/mnt/drive=RW,1234`
+Branches currently have two options which can be set. A
+[mode](#branch-mode) which impacts whether or not the branch is
+included in a policy calculation and a individual
+[minfreespace](#minfreespace) value. The values are set by
+prepending an `=` at the end of a branch designation and using commas
+as delimiters. Example: `/mnt/drive=RW,1234`
 
 
 ### branch mode
@@ -29,7 +31,7 @@ delimiters. Example: `/mnt/drive=RW,1234`
 ### minfreespace
 
 Same purpose and syntax as the [global option](minfreespace.md) but
-specific to the branch. If not set the global value is used.
+specific to the branch. Defaults to the global value.
 
 
 ### globbing
@@ -43,8 +45,8 @@ apply the glob itself.**
 # mergerfs /mnt/hdd\*:/mnt/ssd /media
 ```
 
-The above line will use all mount points in /mnt prefixed with **hdd**
-and **ssd**.
+The above line will use all directories in /mnt prefixed with **hdd**
+as well as **ssd**.
 
 To have the pool mounted at boot or otherwise accessible from related
 tools use `/etc/fstab`.
@@ -54,4 +56,154 @@ tools use `/etc/fstab`.
 /mnt/hdd*:/mnt/ssd    /media          mergerfs  minfreespace=16G      0       0
 ```
 
-**NOTE:** The globbing is done at mount or when updated using the runtime API. If a new directory is added matching the glob after the fact it will not be automatically included.
+**NOTE:** The globbing is done at mount or when updated using the
+runtime API. If a new directory is added matching the glob after the
+fact it will not be automatically included.
+
+A convenient way to configure branches is to use
+[symlinks](../quickstart.md/#etcfstab-w-config-file).
+
+
+## branch setup
+
+mergerfs does not require any special setup of branch paths in order
+to be used however here are some suggestions.
+
+
+### layout
+
+When you have a large collection of storage devices, types of storage,
+and types of interconnects it can be useful to have a verbose naming
+convention. My preference is to create a directory within `/mnt/` for
+each major type of storage device and/or interconnect. `hdd` for
+traditional hard drives; `ssd` for slower SATA based SSDs; `nvme` for
+M.2 or U.2 NVME SSDs; `remote` for NFS, SMB, sshfs, etc.
+
+The mount points within those directories are named after the size of
+the storage and its serial number in the case of physical storage and
+the hostname and remote filesystem for remote.
+
+```
+$ ls -lh /mnt/
+total 16K
+drwxr-xr-x 8 root root 4.0K Aug 18  2024 hdd
+drwxr-xr-x 6 root root 4.0K Oct  8  2024 nvme
+drwxr-xr-x 3 root root 4.0K Aug 24  2024 remote
+drwxr-xr-x 3 root root 4.0K Jul 14  2024 ssd
+
+$ ls -lh /mnt/hdd/
+total 8K
+d--------- 2 root root 4.0K Apr 14 15:58 10T-01234567
+d--------- 2 root root 4.0K Apr 12 20:51 20T-12345678
+
+$ ls -lh /mnt/nvme/
+total 8K
+d--------- 2 root root 4.0K Apr 14 16:00 1T-ABCDEFGH
+d--------- 2 root root 4.0K Apr 14 23:24 1T-BCDEFGHI
+
+$ ls -lh /mnt/remote/
+total 8K
+d--------- 2 root root 4.0K Apr 12 20:23 foo-sshfs
+d--------- 2 root root 4.0K Apr 12 20:24 bar-nfs
+
+# You can find the serial number of a drive using lsblk
+$ lsblk -d -o NAME,PATH,SIZE,SERIAL
+NAME    PATH           SIZE SERIAL
+sda     /dev/sda       9.1T 01234567
+sdb     /dev/sdb      18.2T 12345678
+nvme0n1 /dev/nvme0n1 953.9G ABCDEFGH
+nvme1n1 /dev/nvme1n1 953.9G BCDEFGHI
+```
+
+
+### permissions and mode
+
+#### mount points
+
+To ensure the directory is **only** used as a point to mount another
+filesystem it is good to lock it down as much as possible. Be sure to
+do this **before** mounting a filesystem to it.
+
+```
+$ sudo chown root:root /mnt/hdd/10T-XYZ
+$ sudo chmod 0000 /mnt/hdd/10T-XYZ
+$ sudo setfattr -n user.mergerfs.branch_mounts_here
+$ sudo chattr +i /mnt/hdd/10T-XYZ
+```
+
+The extended attribute `user.mergerfs.branch_mounts_here` is used by
+the [branches-mount-timeout](branches_mount_timeout.md) option to
+recognize whether or not a mergerfs branch path points to the intended
+filesystem.
+
+The `chattr` is likely to only work on EXT{2,3,4} filesystems but will
+restrict even `root` from modifying the directory or its content.
+
+
+#### mounted filesystems
+
+For those new to Linux, intending to be the primary individual logged
+into the system, or simply want to simplify permissions it is
+recommended to set the root of mounted filesystems like `/tmp/` is set
+to. Owned by `root`, `ugo+rwx` and [sticky
+bit](https://en.wikipedia.org/wiki/Sticky_bit) set.
+
+This must be done **after** mounting the filesystem to the target
+mount point.
+
+```
+$ sudo chown root:root /mnt/hdd/10T-SERIALNUM
+$ sudo chmod 1777 /mnt/hdd/10T-SERIALNUM
+$ sudo setfattr -n user.mergerfs.branch /mnt/hdd/10T-SERIALNUM
+```
+
+
+### formatting
+
+While even less relevant to mergerfs than the details above the topic
+does com up regularly with mergerfs users. When it comes to
+partitioning and formatting it is suggested to keep things
+simple. Most users of mergerfs will be using the whole drive capacity
+and as such have a singular partition and filesystem on that
+partition. Something many people don't realize is that the partition
+is not necessary and actually can become problematic.
+
+Rather than creating paritions just format the block device. Let's use
+`/dev/sda` as an example.
+
+```
+$ lsblk -d -o NAME,PATH,SERIAL /dev/sda
+NAME    PATH         SERIAL
+sda     /dev/sda     01234567
+
+$ sudo mkfs.ext4 -m0 -L 01234567 /dev/sda
+mke2fs 1.47.0 (5-Feb-2023)
+Discarding device blocks: done
+Creating filesystem with 262144 4k blocks and 65536 inodes
+Filesystem UUID: ede8bf96-9aff-464e-a4fb-a4ab8a197cd7
+Superblock backups stored on blocks:
+        32768, 98304, 163840, 229376
+
+Allocating group tables: done
+Writing inode tables: done
+Creating journal (8192 blocks): done
+Writing superblocks and filesystem accounting information: done
+```
+
+You can then use the serial number as the identifier in `fstab`.
+
+```
+# <file system>  <mount point>           <type>  <options>  <dump>  <pass>
+LABEL=01234567   /mnt/hdd/10TB-01234567  auto    nofail     0       2
+```
+
+Benefits of doing it this way?
+
+* One less thing (partitions) to configure and worry about.
+* Guarantees alignment of blocks
+* Makes it easier to use the drive with different enclosures. Some
+  SATA to USB adapters use 4K blocks while the drive itself is using
+  512b. If you create partitions with one block size and move the
+  drive to a controller that uses the other the offset on the device
+  where the filesystem starts will be misinterpreted. It is possible
+  to manually fix this but it isn't well documented and avoidable.

mkdocs/docs/config/branches_mount_timeout.md

@@ -0,0 +1,48 @@
+# branches-mount-timeout
+
+Default: `0`
+
+mergerfs is compatible with any path, whether it be a mount point or a
+directory on your [root
+filesystem.](https://en.wikipedia.org/wiki/Root_directory) It doesn’t
+require branch paths to be mounted or to match a specific filesystem
+at startup, and it operates effectively without needing details about
+the intended filesystem. This flexibility eliminates the need to
+manage mount ordering, which is particularly advantageous on modern
+systems where filesystems are mounted asynchronously, resulting in
+unpredictable mount sequences. While
+[systemd](https://www.freedesktop.org/software/systemd/man/latest/systemd.mount.html)
+offers a way to enforce mount dependencies using the
+[x-systemd.requires=PATH](https://www.freedesktop.org/software/systemd/man/latest/systemd.mount.html#x-systemd.requires=)
+option in /etc/fstab, applying this to every branch path is both
+cumbersome and susceptible to errors.
+
+`branches-mount-timeout` will cause mergerfs to wait for all branches
+to become "mounted." The logic to determine "mounted" is as follows.
+
+1. It is mounted if the branch directory has the extended attribute
+   `user.mergerfs.branch`
+2. It is mounted if the branch directory contains a file named
+   `.mergerfs.branch`
+3. It is **not** mounted if the branch directory has the extended
+   attribute `user.mergerfs.branch_mounts_here`
+4. It is **not** mounted if the branch directory contains
+   a file named `.mergerfs.branch_mounts_here`
+5. It is mounted if the `st_dev` value of the mergerfs mountpoint is
+   different from the branch path.
+
+**NOTE:** If on a `systemd` based system and using `fstab` it is a
+good idea to set the mount option
+[x-systemd.mount-timeout](https://www.freedesktop.org/software/systemd/man/latest/systemd.mount.html#x-systemd.mount-timeout=)
+to some value longer than `branches-mount-timeout`.
+
+
+## branches-mount-timeout-fail
+
+Default: `false`
+
+When set to `true` mergerfs will fail entirely after
+`branches-mount-timeout` expires without all branches being
+mounted. If set to `false` it will simply ignore the mount status of
+the branches and continue on. The details will be
+[logged](../error_handling_and_logging.md).

mkdocs/docs/config/functions_categories_policies.md

@@ -1,28 +1,16 @@
 # functions, categories and policies
 
-The POSIX filesystem API is made up of a number of
-functions. **creat**, **stat**, **chown**, etc. For ease of
-configuration in mergerfs, most of the core functions are grouped into
-3 categories: **action**, **create**, and **search**. These functions
-and categories can be assigned a policy which dictates which branch is
-chosen when performing that function.
+The POSIX filesystem API is made up of a number of functions. `creat`,
+`stat`, `chown`, etc. For ease of configuration in mergerfs, most of
+the core functions are grouped into 3 categories: `action`, `create`,
+and `search`. These functions and categories can be assigned a policy
+which dictates which branch is chosen when performing that
+function.
 
 Some functions, listed in the category `N/A` below, can not be
 assigned the normal policies because they are directly related to a
 file which has already been opened.
 
-When using policies which are based on a branch's available space the
-base path provided is used. Not the full path to the file in
-question. Meaning that mounts in the branch won't be considered in the
-space calculations. The reason is that it doesn't really work for
-non-path preserving policies and can lead to non-obvious behaviors.
-
-NOTE: While any policy can be assigned to a function or category,
-some may not be very useful in practice. For instance: **rand**
-(random) may be useful for file creation (create) but could lead to
-very odd behavior if used for `chmod` if there were more than one copy
-of the file.
-
 
 ## Functions and their Category classifications
 
@@ -34,43 +22,61 @@ of the file.
 | N/A      | fchmod, fchown, futimens, ftruncate, fallocate, fgetattr, fsync, ioctl (files), read, readdir, release, statfs, write, copy_file_range |
 
 In cases where something may be searched for (such as a path to clone)
-**getattr** will usually be used.
+`getattr` will usually be used.
 
 
 ## Policies
 
+See below for [available policies and their descriptions](#policy-descriptions).
+
 A policy is an algorithm designed to select one or more branches for a
 function to operate on.
 
-Any function in the `create` category will clone the relative path if
-needed. Some other functions (`rename`,`link`,`ioctl`) have special
-requirements or behaviors which you can read more about below.
+Policies do not actually manage the filesystem or layout. They are
+strictly responsible for deciding which files or branches will be
+worked on in relation to the function being performed. Once the branch
+is chosen other parts of the system does what is necessary to
+accomplish the function. Such as the cloning of directories between
+branches.
+
+When using policies which are based on a branch's available space the
+branch base path provided is used. Not the full path to the file or
+directory in question. Meaning that mounts within the branch will not
+be considered in the space calculations.
+
+NOTE: While any policy can be assigned to a function or category, some
+may not be very useful in practice. For instance: `rand` (random) may
+be useful for file creation but could lead to very odd behavior if
+used for `chmod` if there were more than one copy of the file. Unless
+users find this flexibility useful it will likely be removed in the
+future.
 
 
 ## Filtering
 
-Most policies basically search branches and create a list of files / paths
-for functions to work on. The policy is responsible for filtering and
-sorting the branches. Filters include **minfreespace**, whether or not
-a branch is mounted read-only, and the branch tagging
+Most policies search branches and create a list of files / paths for
+functions to work on. The policy is responsible for filtering and
+sorting the branches. Filters include [minfreespace](minfreespace.md),
+whether or not a branch is mounted read-only, and the branch mode
 (RO,NC,RW). These filters are applied across most policies.
 
-- No **search** function policies filter.
-- All **action** function policies filter out branches which are
-  mounted **read-only** or tagged as **RO (read-only)**.
-- All **create** function policies filter out branches which are
-  mounted **read-only**, tagged **RO (read-only)** or **NC (no
-  create)**, or has available space less than `minfreespace`.
+- No `search` function policies filter.
+- All `action` function policies filter out branches which are
+  mounted **read-only** or mode is **RO (read-only)**.
+- All `create` function policies filter out branches which are
+  mounted **read-only**, mode **RO (read-only)** or **NC (no
+  create)**, or has available space less than
+  [minfreespace](minfreespace.md).
 
 Policies may have their own additional filtering such as those that
 require existing paths to be present.
 
 If all branches are filtered an error will be returned. Typically
-**EROFS** (read-only filesystem) or **ENOSPC** (no space left on
+`EROFS` (read-only filesystem) or `ENOSPC` (no space left on
 device) depending on the most recent reason for filtering a
-branch. **ENOENT** will be returned if no eligible branch is found.
+branch.
 
-If **create**, **mkdir**, **mknod**, or **symlink** fail with `EROFS`
+If `create`, `mkdir`, `mknod`, or `symlink` fail with `EROFS`
 or other fundamental errors then mergerfs will mark any branch found
 to be read-only as such (IE will set the mode `RO`) and will rerun the
 policy and try again. This is mostly for `ext4` filesystems that can
@@ -82,16 +88,12 @@ suddenly become read-only when it encounters an error.
 Policies, as described below, are of two basic classifications. `path
 preserving` and `non-path preserving`.
 
-All policies which start with `ep` (**epff**, **eplfs**, **eplus**,
-**epmfs**, **eprand**) are `path preserving`. `ep` stands for
-`existing path`.
+All policies which start with `ep` (`epff`, `eplfs`, `eplus`, `epmfs`,
+`eprand`) are `path preserving`. `ep` stands for `existing path`.
 
 A path preserving policy will only consider branches where the relative
 path being accessed already exists.
 
-When using non-path preserving policies paths will be cloned to target
-branches as necessary.
-
 With the `msp` or `most shared path` policies they are defined as
 `path preserving` for the purpose of controlling `link` and `rename`'s
 behaviors since `ignorepponrename` is available to disable that
@@ -141,5 +143,5 @@ policies is not appropriate.
 | Category | Policy |
 | -------- | ------ |
 | action   | epall  |
-| create   | epmfs  |
+| create   | pfrd   |
 | search   | ff     |

mkdocs/docs/faq/why_isnt_it_working.md

@@ -17,31 +17,30 @@ anywhere.
 ## Why are all my files ending up on 1 filesystem?!
 
 Did you start with empty filesystems? Are you using an `existing path`
-policy?
+policy such as `epmfs`?
 
-The default create policy is `epmfs`. That is a path preserving
-algorithm. With such a policy for `mkdir` and `create` with a set of
-empty filesystems it will select only 1 filesystem when the first
-directory is created. Anything, files or directories, created in that
-directory will be placed on the same branch because it is preserving
-paths. That is the expected behavior.
+If starting with a set of empty filesystems such a policy will select
+only 1 filesystem when the first directory is created. Anything
+created in that directory will be placed on the same branch because
+that is the point of such a policy. That is the expected behavior.
 
-This may catch new users off guard but this policy is the safest
-policy to have as default as it will not change the general layout of
-the underlying branches. If you do not care about path preservation
-([most should
-not](configuration_and_policies.md#how-can-i-ensure-files-are-collocated-on-the-same-branch))
-and wish your files to be spread across all your filesystems change
-`create.category` to `pfrd`, `rand`, `mfs` or a similarly non-path
-restrictive [policy](../config/functions_categories_policies.md).
+This may catch users off guard but the point of those `existing path`
+policies is to preserve the directory layout and you need to consider
+what that means one event at a time.
+
+To "fix" this situation change the policy. Most users [have little
+reason](configuration_and_policies.md#how-can-i-ensure-files-are-collocated-on-the-same-branch)
+to use such a policy. See the [quick start guide](../quickstart.md)
+and [FAQ](configuration_and_policies.md) for policy recommendations.
 
 
 ## Why do I get an "out of space" / "no space left on device" / ENOSPC error even though there appears to be lots of space available?
 
-First make sure you've read the sections above about [policies, path
+First make sure you've read the sections about [policies, path
 preservation, branch
 filtering,](../config/functions_categories_policies.md) and the
-options `minfreespace`, [moveonenospc](../config/moveonenospc.md),
+options [minfreespace](../config/minfreespace.md),
+[moveonenospc](../config/moveonenospc.md),
 [statfs](../config/statfs.md), and
 [statfs_ignore](../config/statfs.md#statfs_ignore).
 

mkdocs/docs/media_and_publicity.md

@@ -2,79 +2,79 @@
 
 ## Tutorials / Articles
 
-- 2016-02-02 - [Linuxserver.io: The Perfect Media Server 2016](https://blog.linuxserver.io/2016/02/02/the-perfect-media-server-2016/)
-- 2016-08-31 - [ZackReed.me: Mergerfs – another good option to pool your SnapRAID disks](https://zackreed.me/mergerfs-another-good-option-to-pool-your-snapraid-disks/)
-- 2016-11-06 - [Linuxserver.io: Revisiting the HP ProLiant Gen8 G1610T Microserver](https://blog.linuxserver.io/2016/11/06/revisiting-the-hp-proliant-gen8-g1610t-microserver/)
-- 2017-01-17 - [Setting up mergerfs on JBOD's (or a poor mans storage array)](http://corywestropp.com/develop/articles/setting-up-mergerfs/)
-- 2017-06-24 - [Linuxserver.io: The Perfect Media Server 2017](https://blog.linuxserver.io/2017/06/24/the-perfect-media-server-2017/)
-- 2018-02-19 - [Teknophiles: Disk Pooling in Linux with mergerFS](https://web.archive.org/web/20210324184857/https://www.teknophiles.com/2018/02/19/disk-pooling-in-linux-with-mergerfs/)
-- 2018-02-20 - [Fortes.com: Using Rclone and MergerFS together across drives](https://fortes.com/2018/rclone-and-mergerfs/)
-- 2019-02-10 - [Medium: Migrating from ZFS to MergerFS and SnapRAID at home](https://medium.com/@pascal.brokmeier/migrating-from-zfs-to-mergerfs-and-snapraid-at-home-89c45fd5db02)
-- 2019-04-24 - [MichaelXander.com: DIY NAS with OMV, SnapRAID, MergerFS, and Disk Encryption](https://michaelxander.com/diy-nas/)
-- 2019-07-16 - [Linuxserver.io: The Perfect Media Server - 2019 Edition](https://blog.linuxserver.io/2019/07/16/perfect-media-server-2019/)
-- 2019-09-10 - [Rclone VFS and MergerFS Setup](https://docs.usbx.me/books/rclone/page/rclone-vfs-and-mergerfs-setup)
-- 2019-12-20 - [NetworkShinobi.com: SnapRAID and MergerFS on OpenMediaVault](https://www.networkshinobi.com/snapraid-and-mergerfs-on-openmediavault/)
-- 2020-01-14 - [Brandon Rozek's Blog](https://brandonrozek.com/blog/mergerfs/)
-- 2020-02-14 - [SelfHostedHome.com: Combining Different Sized Drives with mergerfs and SnapRAID](https://selfhostedhome.com/combining-different-sized-drives-with-mergerfs-and-snapraid/)
-- 2020-05-01 - [FedoraMagazine.org: Using mergerfs to increase your virtual storage](https://fedoramagazine.org/using-mergerfs-to-increase-your-virtual-storage/)
-- 2020-08-20 - [Setting up Rclone, Mergerfs and Crontab for automated cloud storage](https://bytesized-hosting.com/pages/setting-up-rclone-mergerfs-and-crontab-for-automated-cloud-storage)
-- 2020-11-22 - [Introducing… MergerFS – My FREE UNRAID alternative](https://supertechfreaks.com/introducing-mergerfs-free-unraid-alternative/)
-- 2020-12-30 - [Perfect Media Server](https://perfectmediaserver.com) (a new site with docs fully fleshing out the 'Perfect Media Server' blog series)
-- 2021-07-24 - [Building the Ultimate Linux Home Server - Part 1: Intro, MergerFS, and SnapRAID](https://blog.karaolidis.com/ultimate-home-server-part-1/)
-- 2021-10-31 - [Better Home Storage: MergerFS + SnapRAID on OpenMediaVault](https://blog.sakuragawa.moe/better-home-storage-mergerfs-snapraid-on-openmediavault/)
-- 2021-11-28 - [Linux Magazine: Come Together - Merging file systems for a simple NAS with MergerFS](https://www.linux-magazine.com/Issues/2022/254/MergerFS)
-- 2022-06-04 - [MergerFS + SnapRaid Study](https://crashlaker.github.io/2022/06/04/mergerfs_+_snapraid_study.html)
-- 2022-12-31 - [Merge Storages in CasaOS: A secret beta feature you know now](https://blog.casaos.io/blog/13.html)
-- 2023-02-03 - [(MergerFS + SnapRAID) is the new RAID 5](https://thenomadcode.tech/mergerfs-snapraid-is-the-new-raid-5)
-- 2024-02-07 - [Designing & Deploying MANS - A Hybrid NAS Approach with SnapRAID, MergerFS, and OpenZFS](https://blog.muffn.io/posts/part-3-mini-100tb-nas)
-- 2024-03-11 - [Using MergerFS to combine multiple hard drives into one unified media storage](https://fullmetalbrackets.com/blog/two-drives-mergerfs/)
-- 2024-12-20 - [Pooling multiple drives on my Raspberry Pi with mergerfs](https://sebi.io/posts/2024-12-20-pooling-multiple-drives-with-mergerfs/)
+* 2016-02-02 - [Linuxserver.io: The Perfect Media Server 2016](https://blog.linuxserver.io/2016/02/02/the-perfect-media-server-2016/)
+* 2016-08-31 - [ZackReed.me: Mergerfs – another good option to pool your SnapRAID disks](https://zackreed.me/mergerfs-another-good-option-to-pool-your-snapraid-disks/)
+* 2016-11-06 - [Linuxserver.io: Revisiting the HP ProLiant Gen8 G1610T Microserver](https://blog.linuxserver.io/2016/11/06/revisiting-the-hp-proliant-gen8-g1610t-microserver/)
+* 2017-01-17 - [Setting up mergerfs on JBOD's (or a poor mans storage array)](http://corywestropp.com/develop/articles/setting-up-mergerfs/)
+* 2017-06-24 - [Linuxserver.io: The Perfect Media Server 2017](https://blog.linuxserver.io/2017/06/24/the-perfect-media-server-2017/)
+* 2018-02-19 - [Teknophiles: Disk Pooling in Linux with mergerFS](https://web.archive.org/web/20210324184857/https://www.teknophiles.com/2018/02/19/disk-pooling-in-linux-with-mergerfs/)
+* 2018-02-20 - [Fortes.com: Using Rclone and MergerFS together across drives](https://fortes.com/2018/rclone-and-mergerfs/)
+* 2019-02-10 - [Medium: Migrating from ZFS to MergerFS and SnapRAID at home](https://medium.com/@pascal.brokmeier/migrating-from-zfs-to-mergerfs-and-snapraid-at-home-89c45fd5db02)
+* 2019-04-24 - [MichaelXander.com: DIY NAS with OMV, SnapRAID, MergerFS, and Disk Encryption](https://michaelxander.com/diy-nas/)
+* 2019-07-16 - [Linuxserver.io: The Perfect Media Server - 2019 Edition](https://blog.linuxserver.io/2019/07/16/perfect-media-server-2019/)
+* 2019-09-10 - [Rclone VFS and MergerFS Setup](https://docs.usbx.me/books/rclone/page/rclone-vfs-and-mergerfs-setup)
+* 2019-12-20 - [NetworkShinobi.com: SnapRAID and MergerFS on OpenMediaVault](https://www.networkshinobi.com/snapraid-and-mergerfs-on-openmediavault/)
+* 2020-01-14 - [Brandon Rozek's Blog](https://brandonrozek.com/blog/mergerfs/)
+* 2020-02-14 - [SelfHostedHome.com: Combining Different Sized Drives with mergerfs and SnapRAID](https://selfhostedhome.com/combining-different-sized-drives-with-mergerfs-and-snapraid/)
+* 2020-05-01 - [FedoraMagazine.org: Using mergerfs to increase your virtual storage](https://fedoramagazine.org/using-mergerfs-to-increase-your-virtual-storage/)
+* 2020-08-20 - [Setting up Rclone, Mergerfs and Crontab for automated cloud storage](https://bytesized-hosting.com/pages/setting-up-rclone-mergerfs-and-crontab-for-automated-cloud-storage)
+* 2020-11-22 - [Introducing… MergerFS – My FREE UNRAID alternative](https://supertechfreaks.com/introducing-mergerfs-free-unraid-alternative/)
+* 2020-12-30 - [Perfect Media Server](https://perfectmediaserver.com) (a new site with docs fully fleshing out the 'Perfect Media Server' blog series)
+* 2021-07-24 - [Building the Ultimate Linux Home Server - Part 1: Intro, MergerFS, and SnapRAID](https://blog.karaolidis.com/ultimate-home-server-part-1/)
+* 2021-10-31 - [Better Home Storage: MergerFS + SnapRAID on OpenMediaVault](https://blog.sakuragawa.moe/better-home-storage-mergerfs-snapraid-on-openmediavault/)
+* 2021-11-28 - [Linux Magazine: Come Together - Merging file systems for a simple NAS with MergerFS](https://www.linux-magazine.com/Issues/2022/254/MergerFS)
+* 2022-06-04 - [MergerFS + SnapRaid Study](https://crashlaker.github.io/2022/06/04/mergerfs_+_snapraid_study.html)
+* 2022-12-31 - [Merge Storages in CasaOS: A secret beta feature you know now](https://blog.casaos.io/blog/13.html)
+* 2023-02-03 - [(MergerFS + SnapRAID) is the new RAID 5](https://thenomadcode.tech/mergerfs-snapraid-is-the-new-raid-5)
+* 2024-02-07 - [Designing & Deploying MANS - A Hybrid NAS Approach with SnapRAID, MergerFS, and OpenZFS](https://blog.muffn.io/posts/part-3-mini-100tb-nas)
+* 2024-03-11 - [Using MergerFS to combine multiple hard drives into one unified media storage](https://fullmetalbrackets.com/blog/two-drives-mergerfs/)
+* 2024-12-20 - [Pooling multiple drives on my Raspberry Pi with mergerfs](https://sebi.io/posts/2024-12-20-pooling-multiple-drives-with-mergerfs/)
 
 
 ## Videos
 
-- 2017-06-23 - [Alex Kretzschmar: Part 1 - Perfect Media Server 2017 - Introduction](https://www.youtube.com/watch?v=L5MH8q3lmmk)
-- 2017-06-24 - [Alex Kretzschmar: Part 2 - Perfect Media server 2017 - Installing Debian 9 Stretch](https://www.youtube.com/watch?v=YpVVYRN_L_A)
-- 2017-06-24 - [Alex Kretzschmar: Part 3 - Perfect Media Server 2017 - Install MergerFS and setting up your drives](https://www.youtube.com/watch?v=tbCMfm-jJ5Y)
-- 2017-06-24 - [Alex Kretzschmar: Part 4 - Perfect Media Server 2017 - Installing Docker](https://www.youtube.com/watch?v=WYI32kx4hPE)
-- 2017-06-24 - [Alex Kretzschmar: Part 5 - Perfect Media Server 2017 - Installing and Automating SnapRAID](https://www.youtube.com/watch?v=Ir5ZsUIbHXA)
-- 2017-06-24 - [Alex Kretzschmar: Part 6 - Perfect Media Server 2017 -Turning your server into a NAS with Samba and NFS](https://www.youtube.com/watch?v=1hVdWq758ZQ)
-- 2017-06-24 - [Alex Kretzschmar: Part 7 - Perfect Media Server 2017 - Managing your apps with docker-compose](https://www.youtube.com/watch?v=aI2rdw7_AmE)
-- 2017-06-24 - [Alex Kretzschmar: Part 8 - Perfect Media Server 2017 - Manging your server using a web UI (Cockpit and Portainer)](https://www.youtube.com/watch?v=aLyTWdzDiCg)
-- 2018-04-24 - [ElectronicsWizardy: How to setup a Linux Fileserver with Snapraid and Mergerfs Re-Export](https://www.youtube.com/watch?v=D2Klx-X7pFo)
-- 2019-03-01 - [Snapraid and Unionfs: Advanced Array Options on Openmediavault (Better than ZFS and Unraid)](https://www.youtube.com/watch?v=FYkdPyCt5FU)
-- 2019-03-22 - [Gamexplicit: The Perfect Plex Media Server 2019! Part 1 (Hardware)](https://www.youtube.com/watch?v=rJIRPhM2WcE)
-- 2019-05-13 - [Gamexplicit: The Perfect Plex Media Server 2019! Part 2 (Ubuntu Server 18.04.2 LTS)](https://www.youtube.com/watch?v=aLyTWdzDiCg)
-- 2019-05-20 - [Gamexplicit: The Perfect Plex Media Server 2019! Part 3 (SnapRaid, Samba, Plex)](https://www.youtube.com/watch?v=uW5y43XC-BI)
-- 2020-08-23 - [Installing OpenMediaVault and SnapRAID and UnionFS (mergerfs)](https://www.youtube.com/watch?v=nDvzXM8UjAI)
-- 2021-06-07 - [I ditched TrueNAS for MergerFS - Chia Plot Storage](https://www.youtube.com/watch?v=tpqFywkbZa4)
-- 2021-08-03 - [Install and configure mergerfs to merge more than one folder in the same place](https://www.youtube.com/watch?v=69zcqEy1674)
-- 2021-08-10 - [Instalando e configurando mergerfs para unir mais de uma pasta no mesmo lugar](https://www.youtube.com/watch?v=-RLxbBNBWhU)
-- 2021-08-13 - [Let's Convert an Old Laptop to a NAS - What you should do](https://www.youtube.com/watch?v=F1v-TSbOymI)
-- 2021-08-17 - [How to Combine Multiple Disks as One by using MergerFS | Ubuntu 20.04 LTS](https://www.youtube.com/watch?v=9e46pz5Seo4)
-- 2021-08-20 - [Vamos converter um Laptop antigo para um NAS – O que você deve fazer](https://www.youtube.com/watch?v=q8EK9vWCRTc)
-- 2021-10-29 - [Unlimited space for your Plex using Rclone to connect to your Cloud](https://www.youtube.com/watch?v=ghGconyrF3M)
-- 2022-12-01 - [Make Your Home Server Go FAST! SSD Caching, 10Gbit Networking, etc.](https://www.youtube.com/watch?v=eRfqC_q3lkM&t=784s)
-- 2022-12-07 - [Best RAID for mixed drive sizes. Unraid vs BTRFS vs Snapraid+Mergerfs vs Storage spaces.](https://www.youtube.com/watch?v=NQJkTiLXfgs)
-- 2023-02-21 - [MergerFS + SnapRAID : Forget about RAID 5 in your Home Server !](https://www.youtube.com/watch?v=tX5MA-c6Qq4)
-- 2023-06-26 - [How to install and setup MergerFS](https://www.youtube.com/watch?v=n7piuhTXeG4)
-- 2023-07-31 - [How to recover a dead drive using Snapraid](https://www.youtube.com/watch?v=fmuiRLPcuJE)
-- 2024-01-05 - [OpenMediaVault MergerFS Tutorial (Portuguese)](https://www.youtube.com/watch?v=V6Yw86dRUPQ)
-- 2024-02-19 - [Setup and Install MergerFS and SnapRAID (Part 1)](https://noted.lol/mergerfs-and-snapraid-setup-1/)
-- 2024-02-22 - [Setup and Install MergerFS and SnapRAID (Part 2)](https://noted.lol/mergerfs-and-snapraid-setup-part-2/)
-- 2024-11-15 - [Meu servidor NAS - Parte 18: Recuperando um HD, recuperando o MergerFS e os próximos passos do NAS!](https://www.youtube.com/watch?v=5fy98kPzE3s)
-
+* 2017-06-23 - [Alex Kretzschmar: Part 1 - Perfect Media Server 2017 - Introduction](https://www.youtube.com/watch?v=L5MH8q3lmmk)
+* 2017-06-24 - [Alex Kretzschmar: Part 2 - Perfect Media server 2017 - Installing Debian 9 Stretch](https://www.youtube.com/watch?v=YpVVYRN_L_A)
+* 2017-06-24 - [Alex Kretzschmar: Part 3 - Perfect Media Server 2017 - Install MergerFS and setting up your drives](https://www.youtube.com/watch?v=tbCMfm-jJ5Y)
+* 2017-06-24 - [Alex Kretzschmar: Part 4 - Perfect Media Server 2017 - Installing Docker](https://www.youtube.com/watch?v=WYI32kx4hPE)
+* 2017-06-24 - [Alex Kretzschmar: Part 5 - Perfect Media Server 2017 - Installing and Automating SnapRAID](https://www.youtube.com/watch?v=Ir5ZsUIbHXA)
+* 2017-06-24 - [Alex Kretzschmar: Part 6 - Perfect Media Server 2017 -Turning your server into a NAS with Samba and NFS](https://www.youtube.com/watch?v=1hVdWq758ZQ)
+* 2017-06-24 - [Alex Kretzschmar: Part 7 - Perfect Media Server 2017 - Managing your apps with docker-compose](https://www.youtube.com/watch?v=aI2rdw7_AmE)
+* 2017-06-24 - [Alex Kretzschmar: Part 8 - Perfect Media Server 2017 - Manging your server using a web UI (Cockpit and Portainer)](https://www.youtube.com/watch?v=aLyTWdzDiCg)
+* 2018-04-24 - [ElectronicsWizardy: How to setup a Linux Fileserver with Snapraid and Mergerfs Re-Export](https://www.youtube.com/watch?v=D2Klx-X7pFo)
+* 2019-03-01 - [Snapraid and Unionfs: Advanced Array Options on Openmediavault (Better than ZFS and Unraid)](https://www.youtube.com/watch?v=FYkdPyCt5FU)
+* 2019-03-22 - [Gamexplicit: The Perfect Plex Media Server 2019! Part 1 (Hardware)](https://www.youtube.com/watch?v=rJIRPhM2WcE)
+* 2019-05-13 - [Gamexplicit: The Perfect Plex Media Server 2019! Part 2 (Ubuntu Server 18.04.2 LTS)](https://www.youtube.com/watch?v=aLyTWdzDiCg)
+* 2019-05-20 - [Gamexplicit: The Perfect Plex Media Server 2019! Part 3 (SnapRaid, Samba, Plex)](https://www.youtube.com/watch?v=uW5y43XC-BI)
+* 2020-08-23 - [Installing OpenMediaVault and SnapRAID and UnionFS (mergerfs)](https://www.youtube.com/watch?v=nDvzXM8UjAI)
+* 2021-06-07 - [I ditched TrueNAS for MergerFS - Chia Plot Storage](https://www.youtube.com/watch?v=tpqFywkbZa4)
+* 2021-08-03 - [Install and configure mergerfs to merge more than one folder in the same place](https://www.youtube.com/watch?v=69zcqEy1674)
+* 2021-08-10 - [Instalando e configurando mergerfs para unir mais de uma pasta no mesmo lugar](https://www.youtube.com/watch?v=-RLxbBNBWhU)
+* 2021-08-13 - [Let's Convert an Old Laptop to a NAS - What you should do](https://www.youtube.com/watch?v=F1v-TSbOymI)
+* 2021-08-17 - [How to Combine Multiple Disks as One by using MergerFS | Ubuntu 20.04 LTS](https://www.youtube.com/watch?v=9e46pz5Seo4)
+* 2021-08-20 - [Vamos converter um Laptop antigo para um NAS – O que você deve fazer](https://www.youtube.com/watch?v=q8EK9vWCRTc)
+* 2021-10-29 - [Unlimited space for your Plex using Rclone to connect to your Cloud](https://www.youtube.com/watch?v=ghGconyrF3M)
+* 2022-12-01 - [Make Your Home Server Go FAST! SSD Caching, 10Gbit Networking, etc.](https://www.youtube.com/watch?v=eRfqC_q3lkM&t=784s)
+* 2022-12-07 - [Best RAID for mixed drive sizes. Unraid vs BTRFS vs Snapraid+Mergerfs vs Storage spaces.](https://www.youtube.com/watch?v=NQJkTiLXfgs)
+* 2023-02-21 - [MergerFS + SnapRAID : Forget about RAID 5 in your Home Server !](https://www.youtube.com/watch?v=tX5MA-c6Qq4)
+* 2023-06-26 - [How to install and setup MergerFS](https://www.youtube.com/watch?v=n7piuhTXeG4)
+* 2023-07-31 - [How to recover a dead drive using Snapraid](https://www.youtube.com/watch?v=fmuiRLPcuJE)
+* 2024-01-05 - [OpenMediaVault MergerFS Tutorial (Portuguese)](https://www.youtube.com/watch?v=V6Yw86dRUPQ)
+* 2024-02-19 - [Setup and Install MergerFS and SnapRAID (Part 1)](https://noted.lol/mergerfs-and-snapraid-setup-1/)
+* 2024-02-22 - [Setup and Install MergerFS and SnapRAID (Part 2)](https://noted.lol/mergerfs-and-snapraid-setup-part-2/)
+* 2024-11-15 - [Meu servidor NAS - Parte 18: Recuperando um HD, recuperando o MergerFS e os próximos passos do NAS!](https://www.youtube.com/watch?v=5fy98kPzE3s)
+* 2025-04-23 - [How to build the Perfect Media Server | Part 1 - The Tech Stack | mergerfs, SnapRAID, and docker.](https://www.youtube.com/watch?v=Yt67zz9p0FU)
 
 ## Podcasts
 
-- 2019-11-04 - [Jupiter Extras: A Chat with mergerfs Developer Antonio Musumeci | Jupiter Extras 28](https://www.youtube.com/watch?v=VmJUAyyhSPk)
-- 2019-11-07 - [Jupiter Broadcasting: ZFS Isn’t the Only Option | Self-Hosted 5](https://www.youtube.com/watch?v=JEW7UuKhMJ8)
-- 2023-10-08 - [Self Hosted Episode 105 - Sleeper Storage Technology](https://selfhosted.show/105)
+* 2019-11-04 - [Jupiter Extras: A Chat with mergerfs Developer Antonio Musumeci | Jupiter Extras 28](https://www.youtube.com/watch?v=VmJUAyyhSPk)
+* 2019-11-07 - [Jupiter Broadcasting: ZFS Isn’t the Only Option | Self-Hosted 5](https://www.youtube.com/watch?v=JEW7UuKhMJ8)
+* 2023-10-08 - [Self Hosted Episode 105 - Sleeper Storage Technology](https://selfhosted.show/105)
 
 
 ## Social Media
 
-- [Reddit](https://www.reddit.com/search/?q=mergerfs&sort=new)
-- [X](https://x.com/search?q=mergerfs&src=spelling_expansion_revert_click&f=live)
-- [YouTube](https://www.youtube.com/results?search_query=mergerfs&sp=CAI%253D)
-- [ServeTheHome Forum](https://forums.servethehome.com/index.php?search/3105813/&q=mergerfs&o=date)
+* [Reddit](https://www.reddit.com/search/?q=mergerfs&sort=new)
+* [X](https://x.com/search?q=mergerfs&src=spelling_expansion_revert_click&f=live)
+* [YouTube](https://www.youtube.com/results?search_query=mergerfs&sp=CAI%253D)
+* [ServeTheHome Forum](https://forums.servethehome.com/index.php?search/3105813/&q=mergerfs&o=date)

mkdocs/docs/quickstart.md

@@ -59,6 +59,10 @@ IO.)
 
 ## Usage
 
+For some suggestions on branch setup see [the page on
+branches](config/branches.md#branch-setup).
+
+
 ### Command Line
 
 ```

mkdocs/docs/usage_patterns.md

@@ -4,14 +4,15 @@
 
 Some storage technologies support what is called "tiered" caching. The
 placing of smaller, faster storage as a transparent cache to larger,
-slower storage. NVMe, SSD, Optane in front of traditional HDDs for
+slower storage. NVMe, SSD, or Optane in front of traditional HDDs for
 instance.
 
-mergerfs does not natively support any sort of tiered caching. Most
-users have no use for such a feature and its inclusion would
-complicate the code as it exists today. However, there are a few
-situations where a cache filesystem could help with a typical mergerfs
-setup.
+mergerfs does not natively support any sort of tiered caching
+currently. The truth is for many users a cache would have little or no
+advantage over reading and writing directly. They would be
+bottlenecked by their network, internet connection, or limited size of
+the cache. However, there are a few situations where a tiered cache
+setup could help.
 
 1.  Fast network, slow filesystems, many readers: You've a 10+Gbps
     network with many readers and your regular filesystems can't keep
@@ -34,7 +35,7 @@ dm-cache but there is another solution which requires only mergerfs, a
 script to move files around, and a cron job to run said script.
 
 * Create two mergerfs pools. One which includes just the **slow**
-  branches and one which has both the **fast** branches
+  branches and one which has **both** the **fast** branches
   (SSD,NVME,etc.) and **slow** branches. The **base** pool and the
   **cache** pool.
 * The **cache** pool should have the cache branches listed first in
@@ -43,7 +44,7 @@ script to move files around, and a cron job to run said script.
   probably be `ff`, `lus`, or `lfs`. The latter two under the
   assumption that the cache filesystem(s) are far smaller than the
   backing filesystems.
-* You can also set the **slow** filesystems mode to `NC` which would
+* You can also set the **slow** branches' mode to `NC` which would
   give you the ability to use other `create` policies though that'd
   mean if the cache filesystems fill you'd get "out of space"
   errors. This however may be good as it would indicate the script

mkdocs/mkdocs.yml

@@ -5,6 +5,9 @@ repo_name: mergerfs
 repo_url: https://github.com/trapexit/mergerfs
 edit_uri: edit/master/mkdocs/docs/
 docs_dir: docs
+plugins:
+  - search
+  - tags
 theme:
   name: material
   logo: logo.png
@@ -62,6 +65,7 @@ nav:
   - config/options.md
   - config/deprecated_options.md
   - config/branches.md
+  - config/branches_mount_timeout.md
   - config/functions_categories_policies.md
   - config/minfreespace.md
   - config/func_readdir.md

src/config.cpp

@@ -56,6 +56,7 @@ namespace l
   {
     IFERT("async_read");
     IFERT("branches-mount-timeout");
+    IFERT("branches-mount-timeout-fail");
     IFERT("cache.symlinks");
     IFERT("cache.writeback");
     IFERT("direct-io-allow-mmap");
@@ -85,6 +86,7 @@ Config::Config()
     minfreespace(MINFREESPACE_DEFAULT),
     branches(minfreespace),
     branches_mount_timeout(0),
+    branches_mount_timeout_fail(false),
     cache_attr(1),
     cache_entry(1),
     cache_files(CacheFiles::ENUM::OFF),
@@ -139,6 +141,7 @@ Config::Config()
   _map["auto_cache"]             = &auto_cache;
   _map["branches"]               = &branches;
   _map["branches-mount-timeout"] = &branches_mount_timeout;
+  _map["branches-mount-timeout-fail"] = &branches_mount_timeout_fail;
   _map["cache.attr"]             = &cache_attr;
   _map["cache.entry"]            = &cache_entry;
   _map["cache.files"]            = &cache_files;

src/config.hpp

@@ -41,6 +41,8 @@
 #include "rwlock.hpp"
 #include "tofrom_wrapper.hpp"
 
+#include "ghc/filesystem.hpp"
+
 #include "fuse.h"
 
 #include <cstdint>
@@ -55,6 +57,7 @@ typedef ToFromWrapper<bool>                 ConfigBOOL;
 typedef ToFromWrapper<uint64_t>             ConfigUINT64;
 typedef ToFromWrapper<int>                  ConfigINT;
 typedef ToFromWrapper<std::string>          ConfigSTR;
+typedef ToFromWrapper<ghc::filesystem::path> ConfigPath;
 typedef std::map<std::string,ToFromString*> Str2TFStrMap;
 
 extern const std::string CONTROLFILE;
@@ -108,6 +111,7 @@ public:
   ConfigUINT64   minfreespace;
   Branches       branches;
   ConfigUINT64   branches_mount_timeout;
+  ConfigBOOL     branches_mount_timeout_fail;
   ConfigUINT64   cache_attr;
   ConfigUINT64   cache_entry;
   CacheFiles     cache_files;
@@ -133,7 +137,7 @@ public:
   ConfigBOOL     link_cow;
   LinkEXDEV      link_exdev;
   LogMetrics     log_metrics;
-  ConfigSTR      mountpoint;
+  ConfigPath     mountpoint;
   MoveOnENOSPC   moveonenospc;
   NFSOpenHack    nfsopenhack;
   ConfigBOOL     nullrw;

src/from_string.cpp

@@ -16,12 +16,11 @@
   OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */
 
+#include "from_string.hpp"
+
 #include "ef.hpp"
 #include "errno.hpp"
 
-#include <cstdint>
-#include <string>
-
 #include <stdlib.h>
 
 
@@ -128,4 +127,13 @@ namespace str
   {
     return -EINVAL;
   }
+
+  int
+  from(const std::string &value_,
+       fs::Path          *path_)
+  {
+    *path_ = value_;
+
+    return 0;
+  }
 }

src/from_string.hpp

@@ -18,6 +18,8 @@
 
 #pragma once
 
+#include "fs_path.hpp"
+
 #include <cstdint>
 #include <string>
 
@@ -29,4 +31,5 @@ namespace str
   int from(const std::string &, uint64_t *);
   int from(const std::string &, std::string *);
   int from(const std::string &, const std::string *);
+  int from(const std::string &, fs::Path *);
 }

src/fs_mkdir.hpp

@@ -18,7 +18,7 @@
 
 #pragma once
 
-#include "ghc/filesystem.hpp"
+#include "fs_path.hpp"
 
 #include <string>
 
@@ -49,8 +49,8 @@ namespace fs
   static
   inline
   int
-  mkdir(const ghc::filesystem::path &path_,
-        const mode_t                 mode_)
+  mkdir(const fs::Path &path_,
+        const mode_t    mode_)
   {
     return fs::mkdir(path_.c_str(),mode_);
   }

src/fs_mktemp.cpp

@@ -30,7 +30,7 @@
 #define PAD_LEN             16
 #define MAX_ATTEMPTS        3
 
-static char const   CHARS[]    = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";
+static char const CHARS[] = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";
 static size_t const CHARS_SIZE = (sizeof(CHARS) - 1);
 
 
@@ -57,8 +57,8 @@ namespace l
 namespace fs
 {
   std::tuple<int,std::string>
-  mktemp_in_dir(std::string const dirpath_,
-                int const         flags_)
+  mktemp_in_dir(const std::string dirpath_,
+                const int         flags_)
   {
     int fd;
     int count;
@@ -85,10 +85,10 @@ namespace fs
   }
 
   std::tuple<int,std::string>
-  mktemp(std::string const filepath_,
-         int const         flags_)
+  mktemp(const std::string filepath_,
+         const int         flags_)
   {
-    ghc::filesystem::path filepath{filepath_};
+    fs::Path filepath{filepath_};
 
     return fs::mktemp_in_dir(filepath.parent_path(),flags_);
   }

src/fs_mounts.cpp

@@ -0,0 +1,37 @@
+#include "fs_mounts.hpp"
+
+#include <cstdio>
+
+#include <mntent.h>
+
+#ifdef __linux__
+void
+fs::mounts(fs::MountVec &mounts_)
+{
+  FILE *f;
+
+  f = setmntent("/proc/mounts","r");
+  if(f == NULL)
+    return;
+
+  struct mntent *entry;
+  while((entry = getmntent(f)) != NULL)
+    {
+      fs::Mount m;
+
+      m.dir    = entry->mnt_dir;
+      m.fsname = entry->mnt_fsname;
+      m.type   = entry->mnt_type;
+      m.opts   = entry->mnt_opts;
+
+      mounts_.emplace_back(std::move(m));
+    }
+
+  endmntent(f);
+}
+#else
+void
+fs::mounts(fs::MountVec &mounts_)
+{
+}
+#endif

src/fs_mounts.hpp

@@ -0,0 +1,21 @@
+#pragma once
+
+#include "fs_path.hpp"
+
+#include <vector>
+
+
+namespace fs
+{
+  struct Mount
+  {
+    fs::Path dir;
+    std::string fsname;
+    std::string type;
+    std::string opts;
+  };
+
+  typedef std::vector<fs::Mount> MountVec;
+
+  void mounts(fs::MountVec &mounts);
+}

src/fs_wait_for_mount.cpp

@@ -19,6 +19,10 @@
 #include "fs_wait_for_mount.hpp"
 #include "syslog.hpp"
 
+#include "fs_exists.hpp"
+#include "fs_lstat.hpp"
+#include "fs_lgetxattr.hpp"
+
 #include <functional>
 #include <thread>
 #include <unordered_set>
@@ -44,6 +48,40 @@ namespace std
   };
 }
 
+static
+bool
+_branch_is_mounted(const struct stat &src_st_,
+                   const fs::Path    &branch_path_)
+{
+  int rv;
+  struct stat st;
+  fs::Path filepath;
+
+  rv = fs::lgetxattr(branch_path_,"user.mergerfs.branch",NULL,0);
+  if(rv != -1)
+    return true;
+
+  filepath = branch_path_ / ".mergerfs.branch";
+  rv = fs::exists(filepath);
+  if(rv)
+    return true;
+
+  rv = fs::lgetxattr(branch_path_,"user.mergerfs.branch_mounts_here",NULL,0);
+  if(rv != -1)
+    return false;
+
+  filepath = branch_path_ / ".mergerfs.branch_mounts_here";
+  rv = fs::exists(filepath);
+  if(rv)
+    return false;
+
+  rv = fs::lstat(branch_path_,&st);
+  if(rv == 0)
+    return (st.st_dev != src_st_.st_dev);
+
+  return false;
+}
+
 static
 void
 _check_mounted(const struct stat &src_st_,
@@ -56,30 +94,23 @@ _check_mounted(const struct stat &src_st_,
 
   for(auto const &tgt_path : tgt_paths_)
     {
-      int         rv;
-      struct stat tgt_st;
+      bool mounted;
 
-      rv = fs::stat(tgt_path,&tgt_st);
-      if(rv == 0)
-        {
-          if(tgt_st.st_dev != src_st_.st_dev)
-            successes.push_back(tgt_path);
-          else
-            failures.push_back(tgt_path);
-        }
+      mounted = ::_branch_is_mounted(src_st_,tgt_path);
+      if(mounted)
+        successes.push_back(tgt_path);
       else
-        {
-          failures.push_back(tgt_path);
-        }
+        failures.push_back(tgt_path);
     }
 }
 
 static
-void
+int
 _wait_for_mount(const struct stat               &src_st_,
                 const fs::PathVector            &tgt_paths_,
                 const std::chrono::milliseconds &timeout_)
 {
+  bool first_loop;
   fs::PathVector                                     successes;
   fs::PathVector                                     failures;
   std::unordered_set<fs::Path>                       tgt_paths;
@@ -90,6 +121,7 @@ _wait_for_mount(const struct stat               &src_st_,
   now      = std::chrono::steady_clock::now();
   deadline = now + timeout_;
 
+  first_loop = true;
   while(true)
     {
       if(tgt_paths.empty())
@@ -100,10 +132,17 @@ _wait_for_mount(const struct stat               &src_st_,
       successes.clear();
       failures.clear();
       ::_check_mounted(src_st_,tgt_paths,&successes,&failures);
-      for(auto const &path : successes)
+      for(const auto &path : successes)
         {
           tgt_paths.erase(path);
-          syslog_info("%s is mounted",path.string().c_str());
+          syslog_info("%s is mounted",path.c_str());
+        }
+
+      if(first_loop)
+        {
+          for(const auto &path : failures)
+            syslog_notice("%s is not mounted, waiting",path.c_str());
+          first_loop = false;
         }
 
       std::this_thread::sleep_for(SLEEP_DURATION);
@@ -111,26 +150,24 @@ _wait_for_mount(const struct stat               &src_st_,
     }
 
   for(auto const &path : failures)
-    syslog_notice("%s not mounted within timeout",path.string().c_str());
-  if(!failures.empty())
-    syslog_warning("Continuing to mount mergerfs despite %u branches not "
-                   "being different from the mountpoint filesystem",
-                   failures.size());
+    syslog_notice("%s not mounted within timeout",path.c_str());
+
+  return failures.size();
 }
 
-void
+int
 fs::wait_for_mount(const fs::Path                  &src_path_,
                    const fs::PathVector            &tgt_paths_,
                    const std::chrono::milliseconds &timeout_)
 {
   int rv;
-  struct stat src_st;
+  struct stat src_st = {0};
 
   rv = fs::stat(src_path_,&src_st);
   if(rv == -1)
-    return syslog_error("Error stat'ing mount path: %s (%s)",
-                        src_path_.c_str(),
-                        strerror(errno));
+    syslog_error("Error stat'ing mount path: %s (%s)",
+                 src_path_.c_str(),
+                 strerror(errno));
 
-  ::_wait_for_mount(src_st,tgt_paths_,timeout_);
+  return ::_wait_for_mount(src_st,tgt_paths_,timeout_);
 }

src/fs_wait_for_mount.hpp

@@ -1,6 +1,5 @@
 /*
   ISC License
-
   Copyright (c) 2023, Antonio SJ Musumeci <trapexit@spawn.link>
 
   Permission to use, copy, modify, and/or distribute this software for any
@@ -29,7 +28,7 @@
 
 namespace fs
 {
-  void
+  int
   wait_for_mount(const fs::Path                  &srcpath,
                  const fs::PathVector            &tgtpaths,
                  const std::chrono::milliseconds &timeout);

src/fuse_init.cpp

@@ -19,12 +19,13 @@
 #include "fs_readahead.hpp"
 #include "syslog.hpp"
 
+#include "fs_path.hpp"
+#include "fs_exists.hpp"
+
 #include "fmt/core.h"
 
 #include "fuse.h"
 
-#include "ghc/filesystem.hpp"
-
 #include <thread>
 #include <algorithm>
 
@@ -82,7 +83,7 @@ namespace l
     std::fstream f;
     uint64_t max_pages_limit;
 
-    if(ghc::filesystem::exists(MAX_PAGES_LIMIT_FILEPATH))
+    if(fs::exists(MAX_PAGES_LIMIT_FILEPATH))
       {
         if(cfg_->fuse_msg_size > MAX_FUSE_MSG_SIZE)
           syslog_info("fuse_msg_size > %u: setting it to %u",
@@ -141,8 +142,8 @@ namespace l
 
   static
   void
-  readahead(const std::string path_,
-            const int         readahead_)
+  readahead(const fs::Path path_,
+            const int      readahead_)
   {
     int rv;
 

src/fuse_link.cpp

@@ -32,7 +32,6 @@
 
 using std::string;
 using std::vector;
-namespace gfs = ghc::filesystem;
 
 namespace error
 {
@@ -230,8 +229,8 @@ namespace l
                          fuse_timeouts_t *timeouts_)
   {
     int rv;
-    gfs::path target(oldpath_);
-    gfs::path linkpath(newpath_);
+    fs::Path target(oldpath_);
+    fs::Path linkpath(newpath_);
 
     target = target.lexically_relative(linkpath.parent_path());
 
@@ -278,11 +277,11 @@ namespace l
 
   static
   int
-  link_exdev_abs_pool_symlink(const std::string &mount_,
-                              const char        *oldpath_,
-                              const char        *newpath_,
-                              struct stat       *st_,
-                              fuse_timeouts_t   *timeouts_)
+  link_exdev_abs_pool_symlink(const fs::Path   mount_,
+                              const char      *oldpath_,
+                              const char      *newpath_,
+                              struct stat     *st_,
+                              fuse_timeouts_t *timeouts_)
   {
     int rv;
     StrVec basepaths;

src/fuse_rename.cpp

@@ -315,7 +315,7 @@ namespace l
   int
   rename_exdev_abs_symlink(const Policy::Action &actionPolicy_,
                            const Branches::CPtr &branches_,
-                           const std::string    &mount_,
+                           const gfs::path      &mount_,
                            const gfs::path      &oldfusepath_,
                            const gfs::path      &newfusepath_)
   {

src/mergerfs.cpp

@@ -165,26 +165,51 @@ namespace l
   }
 
   static
-  void
+  bool
   wait_for_mount(const Config::Read &cfg_)
   {
+    int failures;
     fs::PathVector paths;
     std::chrono::milliseconds timeout;
 
     paths = cfg_->branches->to_paths();
 
-    syslog_info("Waiting %u seconds for branches to mount",
-                (uint64_t)cfg_->branches_mount_timeout);
+    syslog_info("Waiting %u seconds for %zu branches to mount",
+                (uint64_t)cfg_->branches_mount_timeout,
+                paths.size());
 
     timeout = std::chrono::milliseconds(cfg_->branches_mount_timeout * 1000);
-    fs::wait_for_mount((std::string)cfg_->mountpoint,
-                       paths,
-                       timeout);
+    failures = fs::wait_for_mount(cfg_->mountpoint,
+                                  paths,
+                                  timeout);
+    if(failures)
+      {
+        if(cfg_->branches_mount_timeout_fail)
+          {
+            syslog_error("%d of %zu branches were not mounted"
+                         " within the timeout of %zus. Exiting",
+                         failures,
+                         paths.size(),
+                         (uint64_t)cfg_->branches_mount_timeout);
+            return true;
+          }
+
+        syslog_warning("Continuing to mount mergerfs despite %d branches not "
+                       "being different from the mountpoint filesystem",
+                       failures);
+      }
+    else
+      {
+        syslog_info("All %zd branches are mounted",
+                    paths.size());
+      }
+
+    return false;
   }
 
   static
   void
-  lazy_umount(const std::string target_)
+  lazy_umount(const fs::Path target_)
   {
     int rv;
 
@@ -276,7 +301,13 @@ namespace l
       }
 
     if(cfg->branches_mount_timeout > 0)
-      l::wait_for_mount(cfg);
+      {
+        bool failure;
+
+        failure = l::wait_for_mount(cfg);
+        if(failure)
+          return 1;
+      }
 
     l::setup_resources(cfg->scheduling_priority);
     l::setup_signal_handlers();

src/option_parser.cpp

@@ -421,7 +421,7 @@ check_for_mount_loop(Config::Write  &cfg_,
   fs::PathVector branches;
   std::error_code ec;
 
-  mount    = (std::string)cfg_->mountpoint;
+  mount    = *cfg_->mountpoint;
   branches = cfg_->branches->to_paths();
   for(const auto &branch : branches)
     {

src/to_string.cpp

@@ -16,6 +16,8 @@
   OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */
 
+#include "to_string.hpp"
+
 #include <cstdint>
 #include <string>
 
@@ -55,4 +57,10 @@ namespace str
   {
     return s_;
   }
+
+  std::string
+  to(const fs::Path &path_)
+  {
+    return path_.string();
+  }
 }

src/to_string.hpp

@@ -18,6 +18,8 @@
 
 #pragma once
 
+#include "fs_path.hpp"
+
 #include <cstdint>
 #include <string>
 
@@ -28,4 +30,5 @@ namespace str
   std::string to(const int);
   std::string to(const uint64_t);
   std::string to(const std::string&);
+  std::string to(const fs::Path&);
 }

src/tofrom_wrapper.hpp

@@ -64,6 +64,13 @@ public:
     return _data;
   }
 
+  const
+  T&
+  operator*() const
+  {
+    return _data;
+  }
+
   T*
   operator->()
   {