Greg Kurz [Wed, 12 Mar 2025 15:29:30 +0000 (16:29 +0100)]
9pfs: Introduce futimens file op
Add an futimens operation to the fs driver and use if when a fid has
a valid file descriptor. This is required to support more cases where
the client wants to do an action on an unlinked file which it still
has an open file decriptor for.
Only 9P2000.L was considered.
Signed-off-by: Greg Kurz <groug@kaod.org> Reviewed-by: Christian Schoenebeck <qemu_oss@crudebyte.com>
Message-Id: <20250312152933.383967-5-groug@kaod.org> Signed-off-by: Christian Schoenebeck <qemu_oss@crudebyte.com>
Greg Kurz [Wed, 12 Mar 2025 15:29:29 +0000 (16:29 +0100)]
9pfs: Introduce ftruncate file op
Add an ftruncate operation to the fs driver and use if when a fid has
a valid file descriptor. This is required to support more cases where
the client wants to do an action on an unlinked file which it still
has an open file decriptor for.
Only 9P2000.L was considered.
Signed-off-by: Greg Kurz <groug@kaod.org> Reviewed-by: Christian Schoenebeck <qemu_oss@crudebyte.com>
Message-Id: <20250312152933.383967-4-groug@kaod.org> Signed-off-by: Christian Schoenebeck <qemu_oss@crudebyte.com>
Greg Kurz [Wed, 12 Mar 2025 15:29:28 +0000 (16:29 +0100)]
9pfs: Don't use file descriptors in core code
v9fs_getattr() currently peeks into V9fsFidOpenState to know if a fid
has a valid file descriptor or directory stream. Even though the fields
are accessible, this is an implementation detail of the local backend
that should not be manipulated directly by the server code.
Abstract that with a new has_valid_file_handle() backend operation.
Signed-off-by: Greg Kurz <groug@kaod.org> Reviewed-by: Christian Schoenebeck <qemu_oss@crudebyte.com>
Message-Id: <20250312152933.383967-3-groug@kaod.org> Signed-off-by: Christian Schoenebeck <qemu_oss@crudebyte.com>
Greg Kurz [Wed, 12 Mar 2025 15:29:27 +0000 (16:29 +0100)]
9pfs: local : Introduce local_fid_fd() helper
Factor out duplicated code to a single helper. More users to come.
Signed-off-by: Greg Kurz <groug@kaod.org> Reviewed-by: Christian Schoenebeck <qemu_oss@crudebyte.com>
Message-Id: <20250312152933.383967-2-groug@kaod.org> Signed-off-by: Christian Schoenebeck <qemu_oss@crudebyte.com>
9pfs: fix FD leak and reduce latency of v9fs_reclaim_fd()
This patch fixes two different bugs in v9fs_reclaim_fd():
1. Reduce latency:
This function calls v9fs_co_close() and v9fs_co_closedir() in a loop. Each
one of the calls adds two thread hops (between main thread and a fs driver
background thread). Each thread hop adds latency, which sums up in
function's loop to a significant duration.
Reduce overall latency by open coding what v9fs_co_close() and
v9fs_co_closedir() do, executing those and the loop itself altogether in
only one background thread block, hence reducing the total amount of
thread hops to only two.
2. Fix file descriptor leak:
The existing code called v9fs_co_close() and v9fs_co_closedir() to close
file descriptors. Both functions check right at the beginning if the 9p
request was cancelled:
if (v9fs_request_cancelled(pdu)) {
return -EINTR;
}
So if client sent a 'Tflush' message, v9fs_co_close() / v9fs_co_closedir()
returned without having closed the file descriptor and v9fs_reclaim_fd()
subsequently freed the FID without its file descriptor being closed, hence
leaking those file descriptors.
This 2nd bug is fixed by this patch as well by open coding v9fs_co_close()
and v9fs_co_closedir() inside of v9fs_reclaim_fd() and not performing the
v9fs_request_cancelled(pdu) check there.
Even though this function is serialized to be always called from main
thread, v9fs_reclaim_fd() is dispatching the coroutine to a worker thread
in between via its v9fs_co_*() calls, hence leading to the situation where
v9fs_reclaim_fd() is effectively executed multiple times simultaniously,
which renders its LRU algorithm useless and causes high latency.
Fix this by adding a simple boolean variable to ensure this function is
only called once at a time. No synchronization needed for this boolean
variable as this function is only entered and returned on main thread.
Fixes: 7a46274529c ('hw/9pfs: Add file descriptor reclaim support') Signed-off-by: Christian Schoenebeck <qemu_oss@crudebyte.com> Reviewed-by: Greg Kurz <groug@kaod.org>
Message-Id: <5c622067efd66dd4ee5eca740dcf263f41db20b2.1741339452.git.qemu_oss@crudebyte.com>
Kevin Wolf [Tue, 29 Apr 2025 15:56:54 +0000 (17:56 +0200)]
file-posix: Fix crash on discard_granularity == 0
Block devices that don't support discard have a discard_granularity of
0. Currently, this results in a division by zero when we try to make
sure that it's a multiple of request_alignment. Only try to update
bs->bl.pdiscard_alignment when we got a non-zero discard_granularity
from sysfs.
Fixes: f605796aae4 ('file-posix: probe discard alignment on Linux block devices') Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com>
Message-ID: <20250429155654.102735-1-kwolf@redhat.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Merge into INDEX_op_{ld,st,ld2,st2}, where "2" indicates that two
inputs or outputs are required. This simplifies the processing of
i64/i128 depending on host word size.
Reviewed-by: Pierrick Bouvier <pierrick.bouvier@linaro.org> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
We were using S32 | U32 for add2/sub2. But the ALGFI and SLGFI
insns that implement this both have uint32_t immediates.
This makes the composite range balanced and
enables use of -0xffffffff ... -0x80000001.
Reviewed-by: Pierrick Bouvier <pierrick.bouvier@linaro.org> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Do not clobber flags if they're live. Required in order
to perform register allocation on add/sub carry opcodes.
LA and AGHI are the same size, so use LA unconditionally.
Reviewed-by: Pierrick Bouvier <pierrick.bouvier@linaro.org> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
target/ppc: Use tcg_gen_addcio_tl for ADD and SUBF
Tested-by: Nicholas Piggin <npiggin@gmail.com> Reviewed-by: Nicholas Piggin <npiggin@gmail.com> Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org> Reviewed-by: Pierrick Bouvier <pierrick.bouvier@linaro.org> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Using addci with two zeros as input in order to capture the value
of the carry-in bit is common. Special case this with sbb+neg so
that we do not have to load 0 into a register first.
Reviewed-by: Pierrick Bouvier <pierrick.bouvier@linaro.org> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
tcg/optimize: With two const operands, prefer 0 in arg1
For most binary operands, two const operands fold.
However, the add/sub carry opcodes have a third input.
Prefer "reg, zero, const" since many risc hosts have a
zero register that can fit a "reg, reg, const" insn format.
Reviewed-by: Pierrick Bouvier <pierrick.bouvier@linaro.org> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Propagate known carry when possible, and simplify the opcodes
to not require carry-in when known. The result will be cleaned
up further by the subsequent liveness analysis pass.
Reviewed-by: Pierrick Bouvier <pierrick.bouvier@linaro.org> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
tcg: Add add/sub with carry opcodes and infrastructure
Liveness needs to track carry-live state in order to
determine if the (hidden) output of the opcode is used.
Code generation needs to track carry-live state in order
to avoid clobbering cpu flags when loading constants.
So far, output routines and backends are unchanged.
Reviewed-by: Pierrick Bouvier <pierrick.bouvier@linaro.org> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
tcg: Sink def, nb_iargs, nb_oargs loads in liveness_pass_1
Sink the sets of the def, nb_iargs, nb_oargs variables to
the default and do_not_remove labels. They're not really
needed beforehand, and it avoids preceding code from having
to keep them up-to-date. Note that def had *not* been kept
up-to-date; thankfully only def->flags had been used and
those bits were constant between opcode changes.
Reviewed-by: Pierrick Bouvier <pierrick.bouvier@linaro.org> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Drop the cast from TCGv_i64 to TCGv_i32 in tcg_gen_extrl_i64_i32
an emit extrl_i64_i32 unconditionally. Move that special case
to tcg_gen_code when we find out if the output is live or dead.
In this way even hosts that canonicalize truncations can make
use of a store directly from the 64-bit host register.
Reviewed-by: Pierrick Bouvier <pierrick.bouvier@linaro.org> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Use TCGOutOpUnary instead of TCGOutOpBswap because the
flags are not used with this opcode; they are merely
present for uniformity with the smaller bswaps.
Reviewed-by: Pierrick Bouvier <pierrick.bouvier@linaro.org> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Tested-by: Nicholas Piggin <npiggin@gmail.com> Reviewed-by: Nicholas Piggin <npiggin@gmail.com> Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org> Reviewed-by: Pierrick Bouvier <pierrick.bouvier@linaro.org> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
projects / thirdparty / qemu.git / log
