mirror of
https://github.com/trapexit/mergerfs.git
synced 2026-10-26 19:01:56 -04:00
Rework open file resource management
This commit is contained in:
Antonio SJ Musumeci
trapexit
parent
ecee84b323
commit
7fc20457ca
11 changed files with 734 additions and 309 deletions
|
|
@ -16,6 +16,33 @@
|
|||
OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
|
||||
*/
|
||||
|
||||
/*
|
||||
FILE CREATION WITH FUSE PASSTHROUGH SUPPORT
|
||||
===========================================
|
||||
|
||||
This file implements FUSE create() which creates a new file and opens it.
|
||||
Unlike fuse_open.cpp, this file does NOT use a retry loop because the
|
||||
kernel guarantees serialization of create operations.
|
||||
|
||||
WHY NO RETRY LOOP?
|
||||
------------------
|
||||
|
||||
The fuse_open.cpp retry loop handles the case where multiple threads race
|
||||
to open an EXISTING file. With create(), the kernel serializes namespace
|
||||
operations at the VFS layer - only one create for a given path can succeed.
|
||||
|
||||
Additionally, when a file is created, FUSE allocates a completely new
|
||||
nodeid (inode number). Since mergerfs never reuses nodeids, there should
|
||||
never be a collision in the open_files map.
|
||||
|
||||
PASSTHROUGH MODE
|
||||
----------------
|
||||
|
||||
Like fuse_open.cpp, this file supports FUSE passthrough mode for improved
|
||||
I/O performance. The backing_id is obtained from fuse_passthrough_open()
|
||||
and stored in the OpenFile entry.
|
||||
*/
|
||||
|
||||
#include "fuse_create.hpp"
|
||||
|
||||
#include "state.hpp"
|
||||
|
|
@ -227,29 +254,26 @@ _(const PassthroughIOEnum e_,
|
|||
|
||||
static
|
||||
int
|
||||
_create_for_insert_lambda(const fuse_req_ctx_t *ctx_,
|
||||
const fs::path &fusepath_,
|
||||
const mode_t mode_,
|
||||
fuse_file_info_t *ffi_,
|
||||
State::OpenFile *of_)
|
||||
_create(const fuse_req_ctx_t *ctx_,
|
||||
const fs::path &fusepath_,
|
||||
mode_t mode_,
|
||||
fuse_file_info_t *ffi_)
|
||||
{
|
||||
int rv;
|
||||
FileInfo *fi;
|
||||
auto &of = state.open_files;
|
||||
|
||||
::_config_to_ffi_flags(cfg,ctx_->pid,ffi_);
|
||||
if(cfg.cache_writeback)
|
||||
::_tweak_flags_cache_writeback(&ffi_->flags);
|
||||
ffi_->noflush = !::_calculate_flush(cfg.flushonclose,
|
||||
ffi_->flags);
|
||||
ffi_->noflush = !::_calculate_flush(cfg.flushonclose,ffi_->flags);
|
||||
|
||||
rv = ::_create(ctx_,
|
||||
cfg.func.getattr.policy,
|
||||
cfg.func.create.policy,
|
||||
cfg.branches,
|
||||
fusepath_,
|
||||
ffi_,
|
||||
mode_,
|
||||
ctx_->umask);
|
||||
int rv = ::_create(ctx_,
|
||||
cfg.func.getattr.policy,
|
||||
cfg.func.create.policy,
|
||||
cfg.branches,
|
||||
fusepath_,
|
||||
ffi_,
|
||||
mode_,
|
||||
ctx_->umask);
|
||||
if(rv == -EROFS)
|
||||
{
|
||||
cfg.branches.find_and_set_mode_ro();
|
||||
|
|
@ -266,10 +290,8 @@ _create_for_insert_lambda(const fuse_req_ctx_t *ctx_,
|
|||
if(rv < 0)
|
||||
return rv;
|
||||
|
||||
fi = FileInfo::from_fh(ffi_->fh);
|
||||
|
||||
of_->ref_count = 1;
|
||||
of_->fi = fi;
|
||||
FileInfo *fi = FileInfo::from_fh(ffi_->fh);
|
||||
int backing_id = INVALID_BACKING_ID;
|
||||
|
||||
switch(_(cfg.passthrough_io,ffi_->flags))
|
||||
{
|
||||
|
|
@ -278,85 +300,42 @@ _create_for_insert_lambda(const fuse_req_ctx_t *ctx_,
|
|||
case _(PassthroughIO::ENUM::RW,O_RDONLY):
|
||||
case _(PassthroughIO::ENUM::RW,O_WRONLY):
|
||||
case _(PassthroughIO::ENUM::RW,O_RDWR):
|
||||
backing_id = FUSE::passthrough_open(fi->fd);
|
||||
if(fuse_backing_id_is_valid(backing_id))
|
||||
{
|
||||
ffi_->backing_id = backing_id;
|
||||
ffi_->passthrough = true;
|
||||
ffi_->keep_cache = false;
|
||||
}
|
||||
break;
|
||||
default:
|
||||
return 0;
|
||||
break;
|
||||
}
|
||||
|
||||
of_->backing_id = FUSE::passthrough_open(fi->fd);
|
||||
if(of_->backing_id < 0)
|
||||
return 0;
|
||||
bool inserted = of.try_emplace(ctx_->nodeid,
|
||||
backing_id,
|
||||
fi);
|
||||
|
||||
ffi_->backing_id = of_->backing_id;
|
||||
ffi_->passthrough = true;
|
||||
ffi_->keep_cache = false;
|
||||
// Really. This should never happen. FUSE should not be allowing a
|
||||
// create for an existing nodeid. mergerfs doesn't reuse nodeids. It
|
||||
// always uses a fixed generation value and always uses new nodeids.
|
||||
if(not inserted)
|
||||
{
|
||||
const char *msg = "nodeid already exists in open_files map";
|
||||
|
||||
FUSE::passthrough_close(backing_id);
|
||||
fs::close(fi->fd);
|
||||
delete fi;
|
||||
|
||||
SysLog::crit(msg);
|
||||
fmt::println(stderr,"{}",msg);
|
||||
|
||||
return -EIO;
|
||||
}
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
||||
static
|
||||
inline
|
||||
auto
|
||||
_create_insert_lambda(const fuse_req_ctx_t *ctx_,
|
||||
const fs::path &fusepath_,
|
||||
const mode_t mode_,
|
||||
fuse_file_info_t *ffi_,
|
||||
int *_rv_)
|
||||
{
|
||||
return
|
||||
[=](auto &val_)
|
||||
{
|
||||
*_rv_ = ::_create_for_insert_lambda(ctx_,
|
||||
fusepath_,
|
||||
mode_,
|
||||
ffi_,
|
||||
&val_.second);
|
||||
};
|
||||
}
|
||||
|
||||
// This function should never be called?
|
||||
static
|
||||
inline
|
||||
auto
|
||||
_create_update_lambda()
|
||||
{
|
||||
return
|
||||
[](const auto &val_)
|
||||
{
|
||||
fmt::println(stderr,"CREATE_UPDATE_LAMBDA: THIS SHOULD NOT HAPPEN");
|
||||
SysLog::crit("CREATE_UPDATE_LAMBDA: THIS SHOULD NOT HAPPEN");
|
||||
abort();
|
||||
};
|
||||
}
|
||||
|
||||
static
|
||||
int
|
||||
_create(const fuse_req_ctx_t *ctx_,
|
||||
const fs::path &fusepath_,
|
||||
mode_t mode_,
|
||||
fuse_file_info_t *ffi_)
|
||||
{
|
||||
int rv;
|
||||
auto &of = state.open_files;
|
||||
|
||||
rv = -EINVAL;
|
||||
of.try_emplace_and_visit(ctx_->nodeid,
|
||||
::_create_insert_lambda(ctx_,fusepath_,mode_,ffi_,&rv),
|
||||
::_create_update_lambda());
|
||||
|
||||
// Can't abort an emplace_and_visit and can't assume another thread
|
||||
// hasn't created an entry since this failure so erase only if
|
||||
// ref_count is default (0).
|
||||
if(rv < 0)
|
||||
of.erase_if(ctx_->nodeid,
|
||||
[](const auto &val_)
|
||||
{
|
||||
return (val_.second.ref_count <= 0);
|
||||
});
|
||||
|
||||
return rv;
|
||||
}
|
||||
|
||||
int
|
||||
FUSE::create(const fuse_req_ctx_t *ctx_,
|
||||
const char *fusepath_,
|
||||
|
|
|
|||
Loading…
Add table
Add a link
Reference in a new issue