Browse Source

add 'inodecalc' option to allow selection of inode calculation algo

pull/775/head
Antonio SJ Musumeci 4 years ago
parent
commit
b4397f7f2e
  1. 79
      README.md
  2. 177
      man/mergerfs.1
  3. 3
      src/config.cpp
  4. 2
      src/config.hpp
  5. 37
      src/config_inodecalc.cpp
  6. 31
      src/config_inodecalc.hpp
  7. 164
      src/fs_inode.cpp
  8. 41
      src/fs_inode.hpp
  9. 9
      src/fuse_fgetattr.cpp
  10. 2
      src/fuse_getattr.cpp
  11. 17
      src/fuse_readdir_linux.cpp
  12. 23
      src/fuse_readdir_plus_linux.cpp
  13. 15
      src/fuse_readdir_plus_posix.cpp
  14. 8
      src/fuse_readdir_posix.cpp

79
README.md

@ -1,6 +1,6 @@
% mergerfs(1) mergerfs user manual
% Antonio SJ Musumeci <trapexit@spawn.link>
% 2020-05-25
% 2020-06-28
# NAME
@ -98,6 +98,7 @@ See the mergerfs [wiki for real world deployments](https://github.com/trapexit/m
* **minfreespace=SIZE**: The minimum space value used for creation policies. Understands 'K', 'M', and 'G' to represent kilobyte, megabyte, and gigabyte respectively. (default: 4G)
* **moveonenospc=BOOL**: When enabled if a **write** fails with **ENOSPC** (no space left on device) or **EDQUOT** (disk quota exceeded) a scan of all drives will be done looking for the drive with the most free space which is at least the size of the file plus the amount which failed to write. An attempt to move the file to that drive will occur (keeping all metadata possible) and if successful the original is unlinked and the write retried. (default: false)
* **use_ino**: Causes mergerfs to supply file/directory inodes rather than libfuse. While not a default it is recommended it be enabled so that linked files share the same inode value.
* **inodecalc=passthrough|path-hash|devino-hash|hybrid-hash**: Selects the inode calculation algorithm. (default: hybrid-hash)
* **dropcacheonclose=BOOL**: When a file is requested to be closed call `posix_fadvise` on it first to instruct the kernel that we no longer need the data and it can drop its cache. Recommended when **cache.files=partial|full|auto-full** to limit double caching. (default: false)
* **symlinkify=BOOL**: When enabled and a file is not writable and its mtime or ctime is older than **symlinkify_timeout** files will be reported as symlinks to the original files. Please read more below before using. (default: false)
* **symlinkify_timeout=INT**: Time to wait, in seconds, to activate the **symlinkify** behavior. (default: 3600)
@ -171,6 +172,37 @@ To have the pool mounted at boot or otherwise accessible from related tools use
**NOTE:** for mounting via **fstab** to work you must have **mount.fuse** installed. For Ubuntu/Debian it is included in the **fuse** package.
### inodecalc
Inodes (st_ino) are unique identifiers within a filesystem. Each mounted filesystem has device ID (st_dev) as well and together they can uniquely identify a file on the whole of the system. Entries on the same device with the same inode are in fact references to the same underlying file. It is a many to one relationship between names and an inode. Directories, however, do not have multiple links on most systems due to the complexity they add.
FUSE allows the server (mergerfs) to set inode values but not device IDs. Creating an inode value is somewhat complex in mergerfs' case as files aren't really in its control. If a policy changes what directory or file is to be selected or something changes out of band it becomes unclear what value should be used. Most software does not to care what the values are but those that do often break if a value changes unexpectedly. The tool `find` will abort a directory walk if it sees a directory inode change. NFS will return stale handle errors if the inode changes out of band. File dedup tools will usually leverage device ids and inodes as a shortcut in searching for duplicate files and would resort to full file comparisons should it find different inode values.
mergerfs offers multiple ways to calculate the inode in hopes of covering different usecases.
* passthrough: Passes through the underlying inode value. Mostly intended for testing as using this does not address any of the problems mentioned above and could confuse file deduplication software as inodes from different filesystems can be the same.
* path-hash: Hashes the relative path of the entry in question. The underlying file's values are completely ignored. This means the inode value will always be the same for that file path. This is useful when using NFS and you make changes out of band such as copy data between branches. This also means that entries that do point to the same file will not be recognizable via inodes. That **does not** mean hard links don't work. They will.
* devino-hash: Hashes the device id and inode of the underlying entry. This won't prevent issues with NFS should the policy pick a different file or files move out of band but will present the same inode for underlying files that do too.
* hybrid-hash: Performs `path-hash` on directories and `devino-hash` on other file types. Since directories can't have hard links the static value won't make a difference and the files will get values useful for finding duplicates. Probably the best to use if not using NFS. As such it is the default.
While there is a risk of hash collision in tests of a couple million entries there were zero collisions. Unlike a typical filesystem FUSE filesystems can reuse inodes and not refer to the same entry. The internal identifier used to reference a file in FUSE is different from the inode value presented. The former is the `nodeid` and is actually a tuple of 2 64bit values: `nodeid` and `generation`. This tuple is not client facing. The inode that is presented to the client is passed through the kernel uninterpreted.
From FUSE docs regarding `use_ino`:
```
Honor the st_ino field in the functions getattr() and
fill_dir(). This value is used to fill in the st_ino field
in the stat(2), lstat(2), fstat(2) functions and the d_ino
field in the readdir(2) function. The filesystem does not
have to guarantee uniqueness, however some applications
rely on this value being unique for the whole filesystem.
Note that this does *not* affect the inode that libfuse
and the kernel use internally (also called the "nodeid").
```
In the future the `use_ino` option will probably be removed as this feature should replace the original libfuse inode calculation strategy. Currently you still need to use `use_ino` in order to enable `inodecalc`.
### fuse_msg_size
FUSE applications communicate with the kernel over a special character device: `/dev/fuse`. A large portion of the overhead associated with FUSE is the cost of going back and forth from user space and kernel space over that device. Generally speaking the fewer trips needed the better the performance will be. Reducing the number of trips can be done a number of ways. Kernel level caching and increasing message sizes being two significant ones. When it comes to reads and writes if the message size is doubled the number of trips are approximately halved.
@ -809,14 +841,13 @@ Use `cache.files=off` and/or `dropcacheonclose=true`. See the section on page ca
#### NFS clients returning ESTALE / Stale file handle
Be sure to use `noforget` and `use_ino` arguments.
NFS does not like out of band changes. That is especially true of inode values.
#### NFS clients don't work
Be sure to use the following options:
Some NFS clients appear to fail when a mergerfs mount is exported. Kodi in particular seems to have issues.
Try enabling the `use_ino` option. Some have reported that it fixes the issue.
* noforget
* use_ino
* inodecalc=path-hash
#### rtorrent fails with ENODEV (No such device)
@ -1005,7 +1036,7 @@ This catches a lot of new users off guard but changing the default would break t
#### Do hard links work?
Yes. You need to use `use_ino` to support proper reporting of inodes.
Yes. You need to use `use_ino` to support proper reporting of inodes but they work regardless. See also the option `inodecalc`.
What mergerfs does not do is fake hard links across branches. Read the section "rename & link" for how it works.
@ -1123,9 +1154,13 @@ Are you using ext4? With reserve for root? mergerfs uses available space for sta
#### Can mergerfs mounts be exported over NFS?
Yes. Due to current usage of libfuse by mergerfs and how NFS interacts with it it is necessary to add `noforget` to mergerfs options to keep from getting "stale file handle" errors.
Yes, however if you do anything which may changes files out of band (including for example using the `newest` policy) it will result in "stale file handle" errors.
Be sure to use the following options:
Some clients (Kodi) have issues in which the contents of the NFS mount will not be presented but users have found that enabling the `use_ino` option often fixes that problem.
* noforget
* use_ino
* inodecalc=path-hash
#### Can mergerfs mounts be exported over Samba / SMB?
@ -1133,30 +1168,6 @@ Some clients (Kodi) have issues in which the contents of the NFS mount will not
Yes. While some users have reported problems it appears to always be related to how Samba is setup in relation to permissions.
#### How are inodes calculated?
https://github.com/trapexit/mergerfs/blob/master/src/fs_inode.hpp
Originally tried to simply OR st_ino and (st_dev << 32) for 64bit systems. After a number of years someone finally ran into a collision that lead to some problems. Traditionally `dev_t` was 16bit and `ino_t` was 32bit so merging into one 64bit value worked but with both types being able to be up to 64bit that is no longer as simple. A proper hash seems like the best compromise. While totally unique inodes are preferred the overhead which would be needed does not seem to be outweighed by the benefits.
While atypical, yes, inodes can be reused and not refer to the same file. The internal id used to reference a file in FUSE is different from the inode value presented. The former is the `nodeid` and is actually a tuple of (nodeid,generation). That tuple is not user facing. The inode is merely metadata passed through the kernel and found using the `stat` family of calls or `readdir`.
From FUSE docs regarding `use_ino`:
```
Honor the st_ino field in the functions getattr() and
fill_dir(). This value is used to fill in the st_ino field
in the stat(2), lstat(2), fstat(2) functions and the d_ino
field in the readdir(2) function. The filesystem does not
have to guarantee uniqueness, however some applications
rely on this value being unique for the whole filesystem.
Note that this does *not* affect the inode that libfuse
and the kernel use internally (also called the "nodeid").
```
Generally collision, if it occurs, shouldn't be a problem. You can turn off the calculation by not using `use_ino`. In the future it might be worth creating different strategies for users to select from.
#### I notice massive slowdowns of writes when enabling cache.files.
When file caching is enabled in any form (`cache.files!=off` or `direct_io=false`) it will issue `getxattr` requests for `security.capability` prior to *every single write*. This will usually result in a performance degregation, especially when using a network filesystem (such as NFS or CIFS/SMB/Samba.) Unfortunately at this moment the kernel is not caching the response.

177
man/mergerfs.1

@ -1,7 +1,7 @@
.\"t
.\" Automatically generated by Pandoc 1.19.2.4
.\"
.TH "mergerfs" "1" "2020\-05\-25" "mergerfs user manual" ""
.TH "mergerfs" "1" "2020\-06\-28" "mergerfs user manual" ""
.hy
.SH NAME
.PP
@ -146,6 +146,10 @@ than libfuse.
While not a default it is recommended it be enabled so that linked files
share the same inode value.
.IP \[bu] 2
\f[B]inodecalc=passthrough|path\-hash|devino\-hash|hybrid\-hash\f[]:
Selects the inode calculation algorithm.
(default: hybrid\-hash)
.IP \[bu] 2
\f[B]dropcacheonclose=BOOL\f[]: When a file is requested to be closed
call \f[C]posix_fadvise\f[] on it first to instruct the kernel that we
no longer need the data and it can drop its cache.
@ -373,6 +377,96 @@ be automatically included.
\f[B]NOTE:\f[] for mounting via \f[B]fstab\f[] to work you must have
\f[B]mount.fuse\f[] installed.
For Ubuntu/Debian it is included in the \f[B]fuse\f[] package.
.SS inodecalc
.PP
Inodes (st_ino) are unique identifiers within a filesystem.
Each mounted filesystem has device ID (st_dev) as well and together they
can uniquely identify a file on the whole of the system.
Entries on the same device with the same inode are in fact references to
the same underlying file.
It is a many to one relationship between names and an inode.
Directories, however, do not have multiple links on most systems due to
the complexity they add.
.PP
FUSE allows the server (mergerfs) to set inode values but not device
IDs.
Creating an inode value is somewhat complex in mergerfs\[aq] case as
files aren\[aq]t really in its control.
If a policy changes what directory or file is to be selected or
something changes out of band it becomes unclear what value should be
used.
Most software does not to care what the values are but those that do
often break if a value changes unexpectedly.
The tool \f[C]find\f[] will abort a directory walk if it sees a
directory inode change.
NFS will return stale handle errors if the inode changes out of band.
File dedup tools will usually leverage device ids and inodes as a
shortcut in searching for duplicate files and would resort to full file
comparisons should it find different inode values.
.PP
mergerfs offers multiple ways to calculate the inode in hopes of
covering different usecases.
.IP \[bu] 2
passthrough: Passes through the underlying inode value.
Mostly intended for testing as using this does not address any of the
problems mentioned above and could confuse file deduplication software
as inodes from different filesystems can be the same.
.IP \[bu] 2
path\-hash: Hashes the relative path of the entry in question.
The underlying file\[aq]s values are completely ignored.
This means the inode value will always be the same for that file path.
This is useful when using NFS and you make changes out of band such as
copy data between branches.
This also means that entries that do point to the same file will not be
recognizable via inodes.
That \f[B]does not\f[] mean hard links don\[aq]t work.
They will.
.IP \[bu] 2
devino\-hash: Hashes the device id and inode of the underlying entry.
This won\[aq]t prevent issues with NFS should the policy pick a
different file or files move out of band but will present the same inode
for underlying files that do too.
.IP \[bu] 2
hybrid\-hash: Performs \f[C]path\-hash\f[] on directories and
\f[C]devino\-hash\f[] on other file types.
Since directories can\[aq]t have hard links the static value won\[aq]t
make a difference and the files will get values useful for finding
duplicates.
Probably the best to use if not using NFS.
As such it is the default.
.PP
While there is a risk of hash collision in tests of a couple million
entries there were zero collisions.
Unlike a typical filesystem FUSE filesystems can reuse inodes and not
refer to the same entry.
The internal identifier used to reference a file in FUSE is different
from the inode value presented.
The former is the \f[C]nodeid\f[] and is actually a tuple of 2 64bit
values: \f[C]nodeid\f[] and \f[C]generation\f[].
This tuple is not client facing.
The inode that is presented to the client is passed through the kernel
uninterpreted.
.PP
From FUSE docs regarding \f[C]use_ino\f[]:
.IP
.nf
\f[C]
Honor\ the\ st_ino\ field\ in\ the\ functions\ getattr()\ and
fill_dir().\ This\ value\ is\ used\ to\ fill\ in\ the\ st_ino\ field
in\ the\ stat(2),\ lstat(2),\ fstat(2)\ functions\ and\ the\ d_ino
field\ in\ the\ readdir(2)\ function.\ The\ filesystem\ does\ not
have\ to\ guarantee\ uniqueness,\ however\ some\ applications
rely\ on\ this\ value\ being\ unique\ for\ the\ whole\ filesystem.
Note\ that\ this\ does\ *not*\ affect\ the\ inode\ that\ libfuse
and\ the\ kernel\ use\ internally\ (also\ called\ the\ "nodeid").
\f[]
.fi
.PP
In the future the \f[C]use_ino\f[] option will probably be removed as
this feature should replace the original libfuse inode calculation
strategy.
Currently you still need to use \f[C]use_ino\f[] in order to enable
\f[C]inodecalc\f[].
.SS fuse_msg_size
.PP
FUSE applications communicate with the kernel over a special character
@ -1748,14 +1842,16 @@ Use \f[C]cache.files=off\f[] and/or \f[C]dropcacheonclose=true\f[].
See the section on page caching.
.SS NFS clients returning ESTALE / Stale file handle
.PP
Be sure to use \f[C]noforget\f[] and \f[C]use_ino\f[] arguments.
.SS NFS clients don\[aq]t work
.PP
Some NFS clients appear to fail when a mergerfs mount is exported.
Kodi in particular seems to have issues.
NFS does not like out of band changes.
That is especially true of inode values.
.PP
Try enabling the \f[C]use_ino\f[] option.
Some have reported that it fixes the issue.
Be sure to use the following options:
.IP \[bu] 2
noforget
.IP \[bu] 2
use_ino
.IP \[bu] 2
inodecalc=path\-hash
.SS rtorrent fails with ENODEV (No such device)
.PP
Be sure to set \f[C]cache.files=partial|full|auto\-full\f[] or turn off
@ -2108,7 +2204,9 @@ together directory content by drive.
.SS Do hard links work?
.PP
Yes.
You need to use \f[C]use_ino\f[] to support proper reporting of inodes.
You need to use \f[C]use_ino\f[] to support proper reporting of inodes
but they work regardless.
See also the option \f[C]inodecalc\f[].
.PP
What mergerfs does not do is fake hard links across branches.
Read the section "rename & link" for how it works.
@ -2317,63 +2415,22 @@ mergerfs uses available space for statfs calculations.
If you\[aq]ve reserved space for root then it won\[aq]t show up.
.SS Can mergerfs mounts be exported over NFS?
.PP
Yes.
Due to current usage of libfuse by mergerfs and how NFS interacts with
it it is necessary to add \f[C]noforget\f[] to mergerfs options to keep
from getting "stale file handle" errors.
Yes, however if you do anything which may changes files out of band
(including for example using the \f[C]newest\f[] policy) it will result
in "stale file handle" errors.
.PP
Some clients (Kodi) have issues in which the contents of the NFS mount
will not be presented but users have found that enabling the
\f[C]use_ino\f[] option often fixes that problem.
Be sure to use the following options:
.IP \[bu] 2
noforget
.IP \[bu] 2
use_ino
.IP \[bu] 2
inodecalc=path\-hash
.SS Can mergerfs mounts be exported over Samba / SMB?
.PP
Yes.
While some users have reported problems it appears to always be related
to how Samba is setup in relation to permissions.
.SS How are inodes calculated?
.PP
https://github.com/trapexit/mergerfs/blob/master/src/fs_inode.hpp
.PP
Originally tried to simply OR st_ino and (st_dev << 32) for 64bit
systems.
After a number of years someone finally ran into a collision that lead
to some problems.
Traditionally \f[C]dev_t\f[] was 16bit and \f[C]ino_t\f[] was 32bit so
merging into one 64bit value worked but with both types being able to be
up to 64bit that is no longer as simple.
A proper hash seems like the best compromise.
While totally unique inodes are preferred the overhead which would be
needed does not seem to be outweighed by the benefits.
.PP
While atypical, yes, inodes can be reused and not refer to the same
file.
The internal id used to reference a file in FUSE is different from the
inode value presented.
The former is the \f[C]nodeid\f[] and is actually a tuple of
(nodeid,generation).
That tuple is not user facing.
The inode is merely metadata passed through the kernel and found using
the \f[C]stat\f[] family of calls or \f[C]readdir\f[].
.PP
From FUSE docs regarding \f[C]use_ino\f[]:
.IP
.nf
\f[C]
Honor\ the\ st_ino\ field\ in\ the\ functions\ getattr()\ and
fill_dir().\ This\ value\ is\ used\ to\ fill\ in\ the\ st_ino\ field
in\ the\ stat(2),\ lstat(2),\ fstat(2)\ functions\ and\ the\ d_ino
field\ in\ the\ readdir(2)\ function.\ The\ filesystem\ does\ not
have\ to\ guarantee\ uniqueness,\ however\ some\ applications
rely\ on\ this\ value\ being\ unique\ for\ the\ whole\ filesystem.
Note\ that\ this\ does\ *not*\ affect\ the\ inode\ that\ libfuse
and\ the\ kernel\ use\ internally\ (also\ called\ the\ "nodeid").
\f[]
.fi
.PP
Generally collision, if it occurs, shouldn\[aq]t be a problem.
You can turn off the calculation by not using \f[C]use_ino\f[].
In the future it might be worth creating different strategies for users
to select from.
.SS I notice massive slowdowns of writes when enabling cache.files.
.PP
When file caching is enabled in any form (\f[C]cache.files!=off\f[] or

3
src/config.cpp

@ -83,6 +83,7 @@ Config::Config()
func(),
fuse_msg_size(FUSE_MAX_MAX_PAGES),
ignorepponrename(false),
inodecalc("hybrid-hash"),
link_cow(false),
minfreespace(MINFREESPACE_DEFAULT),
mount(),
@ -142,6 +143,7 @@ Config::Config()
_map["func.utimens"] = &func.utimens;
_map["fuse_msg_size"] = &fuse_msg_size;
_map["ignorepponrename"] = &ignorepponrename;
_map["inodecalc"] = &inodecalc;
_map["kernel_cache"] = &kernel_cache;
_map["link_cow"] = &link_cow;
_map["minfreespace"] = &minfreespace;
@ -392,7 +394,6 @@ Config::set(const std::string &key_,
return set_raw(key_,value_);
}
std::ostream&
operator<<(std::ostream &os_,
const Config &c_)

2
src/config.hpp

@ -17,6 +17,7 @@
#pragma once
#include "branch.hpp"
#include "config_inodecalc.hpp"
#include "config_readdir.hpp"
#include "enum.hpp"
#include "errno.hpp"
@ -103,6 +104,7 @@ public:
Funcs func;
ConfigUINT64 fuse_msg_size;
ConfigBOOL ignorepponrename;
InodeCalc inodecalc;
ConfigBOOL kernel_cache;
ConfigBOOL link_cow;
ConfigUINT64 minfreespace;

37
src/config_inodecalc.cpp

@ -0,0 +1,37 @@
/*
ISC License
Copyright (c) 2020, Antonio SJ Musumeci <trapexit@spawn.link>
Permission to use, copy, modify, and/or distribute this software for any
purpose with or without fee is hereby granted, provided that the above
copyright notice and this permission notice appear in all copies.
THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
#include "config_inodecalc.hpp"
#include "fs_inode.hpp"
InodeCalc::InodeCalc(const std::string &s_)
{
fs::inode::set_algo(s_);
}
std::string
InodeCalc::to_string(void) const
{
return fs::inode::get_algo();
}
int
InodeCalc::from_string(const std::string &s_)
{
return fs::inode::set_algo(s_);
}

31
src/config_inodecalc.hpp

@ -0,0 +1,31 @@
/*
ISC License
Copyright (c) 2020, Antonio SJ Musumeci <trapexit@spawn.link>
Permission to use, copy, modify, and/or distribute this software for any
purpose with or without fee is hereby granted, provided that the above
copyright notice and this permission notice appear in all copies.
THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
#pragma once
#include "tofrom_string.hpp"
class InodeCalc : public ToFromString
{
public:
InodeCalc(const std::string &);
public:
std::string to_string(void) const;
int from_string(const std::string &);
};

164
src/fs_inode.cpp

@ -0,0 +1,164 @@
/*
ISC License
Copyright (c) 2020, Antonio SJ Musumeci <trapexit@spawn.link>
Permission to use, copy, modify, and/or distribute this software for any
purpose with or without fee is hereby granted, provided that the above
copyright notice and this permission notice appear in all copies.
THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
#include "ef.hpp"
#include "fasthash.h"
#include "fs_inode.hpp"
#include <string>
#include <pthread.h>
#include <stdint.h>
#include <string.h>
#include <sys/stat.h>
typedef uint64_t (*inodefunc_t)(const char*,const uint64_t,const mode_t,const dev_t,const ino_t);
static uint64_t hybrid_hash(const char*,const uint64_t,const mode_t,const dev_t,const ino_t);
static inodefunc_t g_func = hybrid_hash;
static
uint64_t
passthrough(const char *fusepath_,
const uint64_t fusepath_len_,
const mode_t mode_,
const dev_t dev_,
const ino_t ino_)
{
return ino_;
}
static
uint64_t
path_hash(const char *fusepath_,
const uint64_t fusepath_len_,
const mode_t mode_,
const dev_t dev_,
const ino_t ino_)
{
return fasthash64(fusepath_,
fusepath_len_,
fs::inode::MAGIC);
}
static
uint64_t
devino_hash(const char *fusepath_,
const uint64_t fusepath_len_,
const mode_t mode_,
const dev_t dev_,
const ino_t ino_)
{
uint64_t buf[2];
buf[0] = dev_;
buf[1] = ino_;
return fasthash64((void*)&buf[0],
sizeof(buf),
fs::inode::MAGIC);
}
static
uint64_t
hybrid_hash(const char *fusepath_,
const uint64_t fusepath_len_,
const mode_t mode_,
const dev_t dev_,
const ino_t ino_)
{
return (S_ISDIR(mode_) ?
path_hash(fusepath_,fusepath_len_,mode_,dev_,ino_) :
devino_hash(fusepath_,fusepath_len_,mode_,dev_,ino_));
}
namespace fs
{
namespace inode
{
int
set_algo(const std::string &algo_)
{
if(algo_ == "passthrough")
g_func = passthrough;
ef(algo_ == "path-hash")
g_func = path_hash;
ef(algo_ == "devino-hash")
g_func = devino_hash;
ef(algo_ == "hybrid-hash")
g_func = hybrid_hash;
else
return -EINVAL;
return 0;
}
std::string
get_algo(void)
{
if(g_func == passthrough)
return "passthrough";
if(g_func == path_hash)
return "path-hash";
if(g_func == devino_hash)
return "devino-hash";
if(g_func == hybrid_hash)
return "hybrid-hash";
return std::string();
}
uint64_t
calc(const char *fusepath_,
const uint64_t fusepath_len_,
const mode_t mode_,
const dev_t dev_,
const ino_t ino_)
{
return g_func(fusepath_,fusepath_len_,mode_,dev_,ino_);
}
void
calc(const char *fusepath_,
const uint64_t fusepath_len_,
struct stat *st_)
{
st_->st_ino = calc(fusepath_,
fusepath_len_,
st_->st_mode,
st_->st_dev,
st_->st_ino);
}
void
calc(const char *fusepath_,
struct stat *st_)
{
calc(fusepath_,strlen(fusepath_),st_);
}
void
calc(const std::string &fusepath_,
struct stat *st_)
{
calc(fusepath_.c_str(),fusepath_.size(),st_);
}
}
}

41
src/fs_inode.hpp

@ -18,38 +18,33 @@
#pragma once
#include "fasthash.h"
#include <string>
#include <stdint.h>
#include <sys/stat.h>
namespace fs
{
namespace inode
{
static const uint64_t MAGIC = 0x7472617065786974;
inline
uint64_t
recompute(ino_t ino_,
dev_t dev_)
{
uint64_t buf[5];
buf[0] = ino_;
buf[1] = dev_;
buf[2] = buf[0] ^ buf[1];
buf[3] = buf[0] & buf[1];
buf[4] = buf[0] | buf[1];
return fasthash64(&buf[0],sizeof(buf),MAGIC);
}
inline
void
recompute(struct stat *st_)
{
st_->st_ino = recompute(st_->st_ino,st_->st_dev);
}
int set_algo(const std::string &s);
std::string get_algo(void);
uint64_t calc(const char *fusepath,
const uint64_t fusepath_len,
const mode_t mode,
const dev_t dev,
const ino_t ion);
void calc(const char *fusepath,
const uint64_t fusepath_len,
struct stat *st);
void calc(const char *fusepath,
struct stat *st);
void calc(const std::string &fusepath,
struct stat *st);
}
}

9
src/fuse_fgetattr.cpp

@ -26,8 +26,9 @@ namespace l
{
static
int
fgetattr(const int fd_,
struct stat *st_)
fgetattr(const int fd_,
const std::string &fusepath_,
struct stat *st_)
{
int rv;
@ -35,7 +36,7 @@ namespace l
if(rv == -1)
return -errno;
fs::inode::recompute(st_);
fs::inode::calc(fusepath_,st_);
return 0;
}
@ -53,7 +54,7 @@ namespace FUSE
const Config &config = Config::ro();
FileInfo *fi = reinterpret_cast<FileInfo*>(ffi_->fh);
rv = l::fgetattr(fi->fd,st_);
rv = l::fgetattr(fi->fd,fi->fusepath,st_);
timeout_->entry = ((rv >= 0) ?
config.cache_entry :

2
src/fuse_getattr.cpp

@ -84,7 +84,7 @@ namespace l
if(symlinkify_ && symlinkify::can_be_symlink(*st_,symlinkify_timeout_))
st_->st_mode = symlinkify::convert(st_->st_mode);
fs::inode::recompute(st_);
fs::inode::calc(fusepath_,st_);
return 0;
}

17
src/fuse_readdir_linux.cpp

@ -1,5 +1,5 @@
/*
Copyright (c) 2019, Antonio SJ Musumeci <trapexit@spawn.link>
Copyright (c) 2020, Antonio SJ Musumeci <trapexit@spawn.link>
Permission to use, copy, modify, and/or distribute this software for any
purpose with or without fee is hereby granted, provided that the above
@ -40,6 +40,13 @@ using std::vector;
namespace l
{
static
char
denttype(struct linux_dirent *d_)
{
return *((char*)d_ + d_->reclen - 1);
}
static
int
close_free_ret_enomem(int fd_,
@ -61,6 +68,7 @@ namespace l
char *buf;
HashSet names;
string basepath;
string fullpath;
uint64_t namelen;
struct linux_dirent *d;
@ -100,7 +108,12 @@ namespace l
if(rv == 0)
continue;
d->ino = fs::inode::recompute(d->ino,dev);
fullpath = fs::path::make(dirname_,d->name);
d->ino = fs::inode::calc(fullpath.c_str(),
fullpath.size(),
DTTOIF(l::denttype(d)),
dev,
d->ino);
rv = fuse_dirents_add_linux(buf_,d,namelen);
if(rv)

23
src/fuse_readdir_plus_linux.cpp

@ -41,6 +41,14 @@ using std::vector;
namespace l
{
static
char
denttype(struct linux_dirent *d_)
{
return *((char*)d_ + d_->reclen - 1);
}
static
int
close_free_ret_enomem(int fd_,
void *buf_)
@ -63,6 +71,7 @@ namespace l
char *buf;
HashSet names;
string basepath;
string fullpath;
uint64_t namelen;
struct stat st;
fuse_entry_t entry;
@ -110,10 +119,16 @@ namespace l
rv = fs::fstatat_nofollow(dirfd,d->name,&st);
if(rv == -1)
memset(&st,0,sizeof(st));
d->ino = fs::inode::recompute(d->ino,dev);
st.st_ino = d->ino;
{
memset(&st,0,sizeof(st));
st.st_ino = d->ino;
st.st_dev = dev;
st.st_mode = DTTOIF(l::denttype(d));
}
fullpath = fs::path::make(dirname_,d->name);
fs::inode::calc(fullpath,&st);
d->ino = st.st_ino;
rv = fuse_dirents_add_linux_plus(buf_,d,namelen,&entry,&st);
if(rv)

15
src/fuse_readdir_plus_posix.cpp

@ -66,6 +66,7 @@ namespace l
dev_t dev;
HashSet names;
string basepath;
string fullpath;
struct stat st;
uint64_t namelen;
fuse_entry_t entry;
@ -104,10 +105,16 @@ namespace l
rv = fs::fstatat_nofollow(dirfd,de->d_name,&st);
if(rv == -1)
memset(&st,0,sizeof(st));
de->d_ino = fs::inode::recompute(de->d_ino,dev);
st.st_ino = de->d_ino;
{
memset(&st,0,sizeof(st));
st.st_ino = de->d_ino;
st.st_dev = dev;
st.st_mode = DTTOIF(de->d_type);
}
fullpath = fs::path::make(dirname_,de->d_name);
fs::inode::calc(fullpath,&st);
de->d_ino = st.st_ino;
rv = fuse_dirents_add_plus(buf_,de,namelen,&entry,&st);
if(rv)

8
src/fuse_readdir_posix.cpp

@ -63,6 +63,7 @@ namespace l
dev_t dev;
HashSet names;
string basepath;
string fullpath;
uint64_t namelen;
for(size_t i = 0, ei = branches_.size(); i != ei; i++)
@ -91,7 +92,12 @@ namespace l
if(rv == 0)
continue;
de->d_ino = fs::inode::recompute(de->d_ino,dev);
fullpath = fs::path::make(dirname_,de->d_name);
de->d_ino = fs::inode::calc(fullpath.c_str(),
fullpath.size(),
DTTOIF(de->d_type),
dev,
de->d_ino);
rv = fuse_dirents_add(buf_,de,namelen);
if(rv)

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