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* block: remove support for using "file" driver with block/char devicesDaniel P. Berrangé2021-03-181-11/+6Star
| | | | | | | The 'host_device' and 'host_cdrom' drivers must be used instead. Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
* block: refactor bdrv_check_request: add errpVladimir Sementsov-Ogievskiy2021-02-031-1/+1
| | | | | | | | | | | It's better to pass &error_abort than just assert that result is 0: on crash, we'll immediately see the reason in the backtrace. Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Message-Id: <20201211183934.169161-2-vsementsov@virtuozzo.com> Reviewed-by: Eric Blake <eblake@redhat.com> [eblake: fix iotest 206 fallout] Signed-off-by: Eric Blake <eblake@redhat.com>
* block: report errno when flock fcntl failsDavid Edmondson2021-01-261-10/+28
| | | | | | | | | | | | | | | | | When a call to fcntl(2) for the purpose of adding file locks fails with an error other than EAGAIN or EACCES, report the error returned by fcntl. EAGAIN or EACCES are elided as they are considered to be common failures, indicating that a conflicting lock is held by another process. No errors are elided when removing file locks. Signed-off-by: David Edmondson <david.edmondson@oracle.com> Message-Id: <20210113164447.2545785-1-david.edmondson@oracle.com> Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Signed-off-by: Max Reitz <mreitz@redhat.com>
* block: bdrv_mark_request_serialising: split non-waiting functionVladimir Sementsov-Ogievskiy2020-12-181-1/+1
| | | | | | | | | | | | | | | | | | We'll need a separate function, which will only "mark" request serialising with specified align but not wait for conflicting requests. So, it will be like old bdrv_mark_request_serialising(), before merging bdrv_wait_serialising_requests_locked() into it. To reduce the possible mess, let's do the following: Public function that does both marking and waiting will be called bdrv_make_request_serialising, and private function which will only "mark" will be called tracked_request_set_serialising(). Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Message-Id: <20201021145859.11201-6-vsementsov@virtuozzo.com> Signed-off-by: Max Reitz <mreitz@redhat.com>
* block/file-posix: fix a possible undefined behaviorPan Nengyuan2020-12-131-1/+1
| | | | | | | | | | | | | | | local_err is not initialized to NULL, it will cause a assert error as below: qemu/util/error.c:59: error_setv: Assertion `*errp == NULL' failed. Fixes: c6447510690 Reported-by: Euler Robot <euler.robot@huawei.com> Signed-off-by: Pan Nengyuan <pannengyuan@huawei.com> Reviewed-by: Stefano Garzarella <sgarzare@redhat.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Li Qiang <liq3ea@gmail.com> Signed-off-by: Chen Qun <kuhn.chenqun@huawei.com> Message-Id: <20201023061218.2080844-8-kuhn.chenqun@huawei.com> Signed-off-by: Laurent Vivier <laurent@vivier.eu>
* block: introduce BDRV_MAX_LENGTHVladimir Sementsov-Ogievskiy2020-12-111-3/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | We are going to modify block layer to work with 64bit requests. And first step is moving to int64_t type for both offset and bytes arguments in all block request related functions. It's mostly safe (when widening signed or unsigned int to int64_t), but switching from uint64_t is questionable. So, let's first establish the set of requests we want to work with. First signed int64_t should be enough, as off_t is signed anyway. Then, obviously offset + bytes should not overflow. And most interesting: (offset + bytes) being aligned up should not overflow as well. Aligned to what alignment? First thing that comes in mind is bs->bl.request_alignment, as we align up request to this alignment. But there is another thing: look at bdrv_mark_request_serialising(). It aligns request up to some given alignment. And this parameter may be bdrv_get_cluster_size(), which is often a lot greater than bs->bl.request_alignment. Note also, that bdrv_mark_request_serialising() uses signed int64_t for calculations. So, actually, we already depend on some restrictions. Happily, bdrv_get_cluster_size() returns int and bs->bl.request_alignment has 32bit unsigned type, but defined to be a power of 2 less than INT_MAX. So, we may establish, that INT_MAX is absolute maximum for any kind of alignment that may occur with the request. Note, that bdrv_get_cluster_size() is not documented to return power of 2, still bdrv_mark_request_serialising() behaves like it is. Also, backup uses bdi.cluster_size and is not prepared to it not being power of 2. So, let's establish that Qemu supports only power-of-2 clusters and alignments. So, alignment can't be greater than 2^30. Finally to be safe with calculations, to not calculate different maximums for different nodes (depending on cluster size and request_alignment), let's simply set QEMU_ALIGN_DOWN(INT64_MAX, 2^30) as absolute maximum bytes length for Qemu. Actually, it's not much less than INT64_MAX. OK, then, let's apply it to block/io. Let's consider all block/io entry points of offset/bytes: 4 bytes/offset interface functions: bdrv_co_preadv_part(), bdrv_co_pwritev_part(), bdrv_co_copy_range_internal() and bdrv_co_pdiscard() and we check them all with bdrv_check_request(). We also have one entry point with only offset: bdrv_co_truncate(). Check the offset. And one public structure: BdrvTrackedRequest. Happily, it has only three external users: file-posix.c: adopted by this patch write-threshold.c: only read fields test-write-threshold.c: sets obviously small constant values Better is to make the structure private and add corresponding interfaces.. Still it's not obvious what kind of interface is needed for file-posix.c. Let's keep it public but add corresponding assertions. After this patch we'll convert functions in block/io.c to int64_t bytes and offset parameters. We can assume that offset/bytes pair always satisfy new restrictions, and make corresponding assertions where needed. If we reach some offset/bytes point in block/io.c missing bdrv_check_request() it is considered a bug. As well, if block/io.c modifies a offset/bytes request, expanding it more then aligning up to request_alignment, it's a bug too. For all io requests except for discard we keep for now old restriction of 32bit request length. iotest 206 output error message changed, as now test disk size is larger than new limit. Add one more test case with new maximum disk size to cover too-big-L1 case. Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Message-Id: <20201203222713.13507-5-vsementsov@virtuozzo.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
* block/file-posix: fix workaround in raw_do_pwrite_zeroes()Vladimir Sementsov-Ogievskiy2020-12-111-1/+0Star
| | | | | | | | | | | | | | | | We should not set overlap_bytes: 1. Don't worry: it is calculated by bdrv_mark_request_serialising() and will be equal to or greater than bytes anyway. 2. If the request was already aligned up to some greater alignment, than we may break things: we reduce overlap_bytes, and further bdrv_mark_request_serialising() may not help, as it will not restore old bigger alignment. Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Message-Id: <20201203222713.13507-2-vsementsov@virtuozzo.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
* file-posix: check the use_lock before setting the file lockLi Feng2020-12-111-1/+1
| | | | | | | | | | | | | The scenario is that when accessing a volume on an NFS filesystem without supporting the file lock, Qemu will complain "Failed to lock byte 100", even when setting the file.locking = off. We should do file lock related operations only when the file.locking is enabled, otherwise, the syscall of 'fcntl' will return non-zero. Signed-off-by: Li Feng <fengli@smartx.com> Message-Id: <1607341446-85506-1-git-send-email-fengli@smartx.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
* file-posix: allow -EBUSY errors during write zeros on raw block devicesMaxim Levitsky2020-11-171-0/+1
| | | | | | | | | | | On Linux, fallocate(fd, FALLOC_FL_PUNCH_HOLE) when it is used on a block device, without O_DIRECT can return -EBUSY if it races with another write to the same page. Since this is rare and discard is not a critical operation, ignore this error Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com> Message-Id: <20201111153913.41840-2-mlevitsk@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
* block/file: switch to use qemu_open/qemu_create for improved errorsDaniel P. Berrangé2020-09-161-11/+7Star
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Currently at startup if using cache=none on a filesystem lacking O_DIRECT such as tmpfs, at startup QEMU prints qemu-system-x86_64: -drive file=/tmp/foo.img,cache=none: file system may not support O_DIRECT qemu-system-x86_64: -drive file=/tmp/foo.img,cache=none: Could not open '/tmp/foo.img': Invalid argument while at QMP level the hint is missing, so QEMU reports just "error": { "class": "GenericError", "desc": "Could not open '/tmp/foo.img': Invalid argument" } which is close to useless for the end user trying to figure out what they did wrong. With this change at startup QEMU prints qemu-system-x86_64: -drive file=/tmp/foo.img,cache=none: Unable to open '/tmp/foo.img': filesystem does not support O_DIRECT while at the QMP level QEMU reports a massively more informative "error": { "class": "GenericError", "desc": "Unable to open '/tmp/foo.img': filesystem does not support O_DIRECT" } Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com> Reviewed-by: Markus Armbruster <armbru@redhat.com> Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
* util: rename qemu_open() to qemu_open_old()Daniel P. Berrangé2020-09-161-7/+7
| | | | | | | | | | | We want to introduce a new version of qemu_open() that uses an Error object for reporting problems and make this it the preferred interface. Rename the existing method to release the namespace for the new impl. Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com> Reviewed-by: Markus Armbruster <armbru@redhat.com> Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
* file-posix: Handle `EINVAL` fallocate return valueAntoine Damhet2020-07-211-1/+5
| | | | | | | | | | | | | | | | The `detect-zeroes=unmap` option may issue unaligned `FALLOC_FL_PUNCH_HOLE` requests, raw block devices can (and will) return `EINVAL`, qemu should then write the zeroes to the blockdev instead of issuing an `IO_ERROR`. The problem can be reprodced like this: $ qemu-io -c 'write -P 0 42 1234' --image-opts driver=host_device,filename=/dev/loop0,detect-zeroes=unmap write failed: Invalid argument Signed-off-by: Antoine Damhet <antoine.damhet@blade-group.com> Message-Id: <20200717135603.51180-1-antoine.damhet@blade-group.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
* file-posix: Fix leaked fd in raw_open_common() error pathKevin Wolf2020-07-171-0/+3
| | | | | | | Signed-off-by: Kevin Wolf <kwolf@redhat.com> Message-Id: <20200717105426.51134-4-kwolf@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
* file-posix: Fix check_hdev_writable() with auto-read-onlyKevin Wolf2020-07-171-12/+21
| | | | | | | | | | | | | | | | | | | | | | | For Linux block devices, being able to open the device read-write doesn't necessarily mean that the device is actually writable (one example is a read-only LV, as you get with lvchange -pr <device>). We have check_hdev_writable() to check this condition and fail opening the image read-write if it's not actually writable. However, this check doesn't take auto-read-only into account, but results in a hard failure instead of downgrading to read-only where possible. Fix this and do the writable check not based on BDRV_O_RDWR, but only when this actually results in opening the file read-write. A second check is inserted in raw_reconfigure_getfd() to have the same check when dynamic auto-read-only upgrades an image file from read-only to read-write. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Message-Id: <20200717105426.51134-3-kwolf@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
* file-posix: Move check_hdev_writable() upKevin Wolf2020-07-171-33/+33
| | | | | | | | | | We'll need to call it in raw_open_common(), so move the function to avoid a forward declaration. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Message-Id: <20200717105426.51134-2-kwolf@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
* file-posix: Allow byte-aligned O_DIRECT with NFSKevin Wolf2020-07-171-1/+25
| | | | | | | | | | | | | | | | | | | | Since commit a6b257a08e3 ('file-posix: Handle undetectable alignment'), we assume that if we open a file with O_DIRECT and alignment probing returns 1, we just couldn't find out the real alignment requirement because some filesystems make the requirement only for allocated blocks. In this case, a safe default of 4k is used. This is too strict for NFS, which does actually allow byte-aligned requests even with O_DIRECT. Because we can't distinguish both cases with generic code, let's just look at the file system magic and disable s->needs_alignment for NFS. This way, O_DIRECT can still be used on NFS for images that are not aligned to 4k. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Message-Id: <20200716142601.111237-3-kwolf@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
* file-posix: Mitigate file fragmentation with extent size hintsKevin Wolf2020-07-141-0/+44
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Especially when O_DIRECT is used with image files so that the page cache indirection can't cause a merge of allocating requests, the file will fragment on the file system layer, with a potentially very small fragment size (this depends on the requests the guest sent). On Linux, fragmentation can be reduced by setting an extent size hint when creating the file (at least on XFS, it can't be set any more after the first extent has been allocated), basically giving raw files a "cluster size" for allocation. This adds a create option to set the extent size hint, and changes the default from not setting a hint to setting it to 1 MB. The main reason why qcow2 defaults to smaller cluster sizes is that COW becomes more expensive, which is not an issue with raw files, so we can choose a larger size. The tradeoff here is only potentially wasted disk space. For qcow2 (or other image formats) over file-posix, the advantage should even be greater because they grow sequentially without leaving holes, so there won't be wasted space. Setting even larger extent size hints for such images may make sense. This can be done with the new option, but let's keep the default conservative for now. The effect is very visible with a test that intentionally creates a badly fragmented file with qemu-img bench (the time difference while creating the file is already remarkable) and then looks at the number of extents and the time a simple "qemu-img map" takes. Without an extent size hint: $ ./qemu-img create -f raw -o extent_size_hint=0 ~/tmp/test.raw 10G Formatting '/home/kwolf/tmp/test.raw', fmt=raw size=10737418240 extent_size_hint=0 $ ./qemu-img bench -f raw -t none -n -w ~/tmp/test.raw -c 1000000 -S 8192 -o 0 Sending 1000000 write requests, 4096 bytes each, 64 in parallel (starting at offset 0, step size 8192) Run completed in 25.848 seconds. $ ./qemu-img bench -f raw -t none -n -w ~/tmp/test.raw -c 1000000 -S 8192 -o 4096 Sending 1000000 write requests, 4096 bytes each, 64 in parallel (starting at offset 4096, step size 8192) Run completed in 19.616 seconds. $ filefrag ~/tmp/test.raw /home/kwolf/tmp/test.raw: 2000000 extents found $ time ./qemu-img map ~/tmp/test.raw Offset Length Mapped to File 0 0x1e8480000 0 /home/kwolf/tmp/test.raw real 0m1,279s user 0m0,043s sys 0m1,226s With the new default extent size hint of 1 MB: $ ./qemu-img create -f raw -o extent_size_hint=1M ~/tmp/test.raw 10G Formatting '/home/kwolf/tmp/test.raw', fmt=raw size=10737418240 extent_size_hint=1048576 $ ./qemu-img bench -f raw -t none -n -w ~/tmp/test.raw -c 1000000 -S 8192 -o 0 Sending 1000000 write requests, 4096 bytes each, 64 in parallel (starting at offset 0, step size 8192) Run completed in 11.833 seconds. $ ./qemu-img bench -f raw -t none -n -w ~/tmp/test.raw -c 1000000 -S 8192 -o 4096 Sending 1000000 write requests, 4096 bytes each, 64 in parallel (starting at offset 4096, step size 8192) Run completed in 10.155 seconds. $ filefrag ~/tmp/test.raw /home/kwolf/tmp/test.raw: 178 extents found $ time ./qemu-img map ~/tmp/test.raw Offset Length Mapped to File 0 0x1e8480000 0 /home/kwolf/tmp/test.raw real 0m0,061s user 0m0,040s sys 0m0,014s Signed-off-by: Kevin Wolf <kwolf@redhat.com> Message-Id: <20200707142329.48303-1-kwolf@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
* error: Eliminate error_propagate() with Coccinelle, part 2Markus Armbruster2020-07-101-4/+2Star
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When all we do with an Error we receive into a local variable is propagating to somewhere else, we can just as well receive it there right away. The previous commit did that with a Coccinelle script I consider fairly trustworthy. This commit uses the same script with the matching of return taken out, i.e. we convert if (!foo(..., &err)) { ... error_propagate(errp, err); ... } to if (!foo(..., errp)) { ... ... } This is unsound: @err could still be read between afterwards. I don't know how to express "no read of @err without an intervening write" in Coccinelle. Instead, I manually double-checked for uses of @err. Suboptimal line breaks tweaked manually. qdev_realize() simplified further to placate scripts/checkpatch.pl. Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Message-Id: <20200707160613.848843-36-armbru@redhat.com>
* error: Eliminate error_propagate() with Coccinelle, part 1Markus Armbruster2020-07-101-6/+2Star
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When all we do with an Error we receive into a local variable is propagating to somewhere else, we can just as well receive it there right away. Convert if (!foo(..., &err)) { ... error_propagate(errp, err); ... return ... } to if (!foo(..., errp)) { ... ... return ... } where nothing else needs @err. Coccinelle script: @rule1 forall@ identifier fun, err, errp, lbl; expression list args, args2; binary operator op; constant c1, c2; symbol false; @@ if ( ( - fun(args, &err, args2) + fun(args, errp, args2) | - !fun(args, &err, args2) + !fun(args, errp, args2) | - fun(args, &err, args2) op c1 + fun(args, errp, args2) op c1 ) ) { ... when != err when != lbl: when strict - error_propagate(errp, err); ... when != err ( return; | return c2; | return false; ) } @rule2 forall@ identifier fun, err, errp, lbl; expression list args, args2; expression var; binary operator op; constant c1, c2; symbol false; @@ - var = fun(args, &err, args2); + var = fun(args, errp, args2); ... when != err if ( ( var | !var | var op c1 ) ) { ... when != err when != lbl: when strict - error_propagate(errp, err); ... when != err ( return; | return c2; | return false; | return var; ) } @depends on rule1 || rule2@ identifier err; @@ - Error *err = NULL; ... when != err Not exactly elegant, I'm afraid. The "when != lbl:" is necessary to avoid transforming if (fun(args, &err)) { goto out } ... out: error_propagate(errp, err); even though other paths to label out still need the error_propagate(). For an actual example, see sclp_realize(). Without the "when strict", Coccinelle transforms vfio_msix_setup(), incorrectly. I don't know what exactly "when strict" does, only that it helps here. The match of return is narrower than what I want, but I can't figure out how to express "return where the operand doesn't use @err". For an example where it's too narrow, see vfio_intx_enable(). Silently fails to convert hw/arm/armsse.c, because Coccinelle gets confused by ARMSSE being used both as typedef and function-like macro there. Converted manually. Line breaks tidied up manually. One nested declaration of @local_err deleted manually. Preexisting unwanted blank line dropped in hw/riscv/sifive_e.c. Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Message-Id: <20200707160613.848843-35-armbru@redhat.com>
* qemu-option: Use returned bool to check for failureMarkus Armbruster2020-07-101-4/+2Star
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The previous commit enables conversion of foo(..., &err); if (err) { ... } to if (!foo(..., &err)) { ... } for QemuOpts functions that now return true / false on success / error. Coccinelle script: @@ identifier fun = { opts_do_parse, parse_option_bool, parse_option_number, parse_option_size, qemu_opt_parse, qemu_opt_rename, qemu_opt_set, qemu_opt_set_bool, qemu_opt_set_number, qemu_opts_absorb_qdict, qemu_opts_do_parse, qemu_opts_from_qdict_entry, qemu_opts_set, qemu_opts_validate }; expression list args, args2; typedef Error; Error *err; @@ - fun(args, &err, args2); - if (err) + if (!fun(args, &err, args2)) { ... } A few line breaks tidied up manually. Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Message-Id: <20200707160613.848843-15-armbru@redhat.com> [Conflict with commit 0b6786a9c1 "block/amend: refactor qcow2 amend options" resolved by rerunning Coccinelle on master's version]
* block/file-posix: drop unallocated_blocks_are_zeroVladimir Sementsov-Ogievskiy2020-07-061-3/+0Star
| | | | | | | | | | | raw_co_block_status() in block/file-posix.c never returns 0, so unallocated_blocks_are_zero is useless (it doesn't affect the only user of the field: bdrv_co_block_status()). Drop it. Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Reviewed-by: Eric Blake <eblake@redhat.com> Message-Id: <20200528094405.145708-8-vsementsov@virtuozzo.com> Signed-off-by: Max Reitz <mreitz@redhat.com>
* block: Drop unused .bdrv_has_zero_init_truncateEric Blake2020-05-081-1/+0Star
| | | | | | | | | | | | | | | | | | Now that there are no clients of bdrv_has_zero_init_truncate, none of the drivers need to worry about providing it. What's more, this eliminates a source of some confusion: a literal reading of the documentation as written in ceaca56f and implemented in commit 1dcaf527 claims that a driver which returns 0 for bdrv_has_zero_init_truncate() must not return 1 for bdrv_has_zero_init(); this condition was violated for parallels, qcow, and sometimes for vdi, although in practice it did not matter since those drivers also lacked .bdrv_co_truncate. Signed-off-by: Eric Blake <eblake@redhat.com> Message-Id: <20200428202905.770727-10-eblake@redhat.com> Acked-by: Richard W.M. Jones <rjones@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
* Compress lines for immediate returnSimran Singhal2020-05-041-5/+3Star
| | | | | | | | | | | | | | | | | | | | | | | | | | | | Compress two lines into a single line if immediate return statement is found. It also remove variables progress, val, data, ret and sock as they are no longer needed. Remove space between function "mixer_load" and '(' to fix the checkpatch.pl error:- ERROR: space prohibited between function name and open parenthesis '(' Done using following coccinelle script: @@ local idexpression ret; expression e; @@ -ret = +return e; -return ret; Signed-off-by: Simran Singhal <singhalsimran0@gmail.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Message-Id: <20200401165314.GA3213@simran-Inspiron-5558> [lv: in handle_aiocb_write_zeroes_unmap() move "int ret" inside the #ifdef] Signed-off-by: Laurent Vivier <laurent@vivier.eu>
* file-posix: Support BDRV_REQ_ZERO_WRITE for truncateKevin Wolf2020-04-301-0/+4
| | | | | | | | | | | | For regular files, we always get BDRV_REQ_ZERO_WRITE behaviour from the OS, so we can advertise the flag and just ignore it. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Reviewed-by: Alberto Garcia <berto@igalia.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Message-Id: <20200424125448.63318-7-kwolf@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
* block: Add flags to BlockDriver.bdrv_co_truncate()Kevin Wolf2020-04-301-1/+1
| | | | | | | | | | | | | | | | This adds a new BdrvRequestFlags parameter to the .bdrv_co_truncate() driver callbacks, and a supported_truncate_flags field in BlockDriverState that allows drivers to advertise support for request flags in the context of truncate. For now, we always pass 0 and no drivers declare support for any flag. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Reviewed-by: Alberto Garcia <berto@igalia.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Message-Id: <20200424125448.63318-2-kwolf@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
* block/file-posix: Fix check_cache_dropped() error handlingMarkus Armbruster2020-04-291-1/+4
| | | | | | | | | | | | | | | | | | | | The Error ** argument must be NULL, &error_abort, &error_fatal, or a pointer to a variable containing NULL. Passing an argument of the latter kind twice without clearing it in between is wrong: if the first call sets an error, it no longer points to NULL for the second call. check_cache_dropped() calls error_setg() in a loop. It fails to break the loop in one instance. If a subsequent iteration error_setg()s again, it trips error_setv()'s assertion. Fix it to break the loop. Fixes: 31be8a2a97ecba7d31a82932286489cac318e9e9 Cc: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Message-Id: <20200422130719.28225-3-armbru@redhat.com>
* block: trickle down the fallback image creation function use to the block ↵Maxim Levitsky2020-03-261-1/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | drivers Instead of checking the .bdrv_co_create_opts to see if we need the fallback, just implement the .bdrv_co_create_opts in the drivers that need it. This way we don't break various places that need to know if the underlying protocol/format really supports image creation, and this way we still allow some drivers to not support image creation. Fixes: fd17146cd93d1704cd96d7c2757b325fc7aac6fd Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=1816007 Note that technically this driver reverts the image creation fallback for the vxhs driver since I don't have a means to test it, and IMHO it is better to leave it not supported as it was prior to generic image creation patches. Also drop iscsi_create_opts which was left accidentally. Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com> Message-Id: <20200326011218.29230-3-mlevitsk@redhat.com> Reviewed-by: Denis V. Lunev <den@openvz.org> [mreitz: Fixed alignment, and moved bdrv_co_create_opts_simple() and bdrv_create_opts_simple from block.h into block_int.h] Signed-off-by: Max Reitz <mreitz@redhat.com>
* block: pass BlockDriver reference to the .bdrv_co_createMaxim Levitsky2020-03-261-1/+3
| | | | | | | | | | | This will allow the reuse of a single generic .bdrv_co_create implementation for several drivers. No functional changes. Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com> Message-Id: <20200326011218.29230-2-mlevitsk@redhat.com> Reviewed-by: Denis V. Lunev <den@openvz.org> Signed-off-by: Max Reitz <mreitz@redhat.com>
* block: introducing 'bdrv_co_delete_file' interfaceDaniel Henrique Barboza2020-03-111-0/+23
| | | | | | | | | | | | | | | | Adding to Block Drivers the capability of being able to clean up its created files can be useful in certain situations. For the LUKS driver, for instance, a failure in one of its authentication steps can leave files in the host that weren't there before. This patch adds the 'bdrv_co_delete_file' interface to block drivers and add it to the 'file' driver in file-posix.c. The implementation is given by 'raw_co_delete_file'. Suggested-by: Daniel P. Berrangé <berrange@redhat.com> Signed-off-by: Daniel Henrique Barboza <danielhb413@gmail.com> Message-Id: <20200130213907.2830642-2-danielhb413@gmail.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
* block/file-posix: Remove redundant statement in raw_handle_perm_lock()Chen Qun2020-03-091-1/+0Star
| | | | | | | | | | | | | Clang static code analyzer show warning: block/file-posix.c:891:9: warning: Value stored to 'op' is never read op = RAW_PL_ABORT; ^ ~~~~~~~~~~~~ Reported-by: Euler Robot <euler.robot@huawei.com> Signed-off-by: Chen Qun <kuhn.chenqun@huawei.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Message-Id: <20200302130715.29440-5-kuhn.chenqun@huawei.com> Signed-off-by: Laurent Vivier <laurent@vivier.eu>
* file-posix: Drop hdev_co_create_opts()Max Reitz2020-02-201-67/+0Star
| | | | | | | | | The generic fallback implementation effectively does the same. Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com> Signed-off-by: Max Reitz <mreitz@redhat.com> Message-Id: <20200122164532.178040-4-mreitz@redhat.com> Signed-off-by: Max Reitz <mreitz@redhat.com>
* block/file-posix.c: extend to use io_uringAarushi Mehta2020-01-301-19/+79
| | | | | | | | | | Signed-off-by: Aarushi Mehta <mehta.aaru20@gmail.com> Reviewed-by: Maxim Levitsky <maximlevitsky@gmail.com> Acked-by: Stefano Garzarella <sgarzare@redhat.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Message-id: 20200120141858.587874-9-stefanha@redhat.com Message-Id: <20200120141858.587874-9-stefanha@redhat.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
* block/io: wait for serialising requests when a request becomes serialisingPaolo Bonzini2020-01-301-1/+0Star
| | | | | | | | | | | Marking without waiting would not result in actual serialising behavior. Thus, make a call bdrv_mark_request_serialising sufficient for serialisation to happen. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Message-id: 1578495356-46219-3-git-send-email-pbonzini@redhat.com Message-Id: <1578495356-46219-3-git-send-email-pbonzini@redhat.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
* block/file-posix: Fix laio_init() error handling crash bugMarkus Armbruster2019-12-021-1/+1
| | | | | | | | | | | | | | | | | | raw_aio_attach_aio_context() passes uninitialized Error *local_err by reference to laio_init() via aio_setup_linux_aio(). When laio_init() fails, it passes it on to error_setg_errno(), tripping error_setv()'s assertion unless @local_err is null by dumb luck. Fix by initializing @local_err properly. Fixes: ed6e2161715c527330f936d44af4c547f25f687e Cc: Nishanth Aravamudan <naravamudan@digitalocean.com> Cc: Stefan Hajnoczi <stefanha@redhat.com> Cc: Kevin Wolf <kwolf@redhat.com> Signed-off-by: Markus Armbruster <armbru@redhat.com> Message-Id: <20191130194240.10517-4-armbru@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com>
* block/file-posix: Let post-EOF fallocate serializeMax Reitz2019-11-041-0/+36
| | | | | | | | | | | | The XFS kernel driver has a bug that may cause data corruption for qcow2 images as of qemu commit c8bb23cbdbe32f. We can work around it by treating post-EOF fallocates as serializing up until infinity (INT64_MAX in practice). Cc: qemu-stable@nongnu.org Signed-off-by: Max Reitz <mreitz@redhat.com> Message-id: 20191101152510.11719-4-mreitz@redhat.com Signed-off-by: Max Reitz <mreitz@redhat.com>
* Merge remote-tracking branch 'remotes/maxreitz/tags/pull-block-2019-10-28' ↵Peter Maydell2019-10-281-2/+9
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | into staging Block patches for softfreeze: - iotest patches - Improve performance of the mirror block job in write-blocking mode - Limit memory usage for the backup block job - Add discard and write-zeroes support to the NVMe host block driver - Fix a bug in the mirror job - Prevent the qcow2 driver from creating technically non-compliant qcow2 v3 images (where there is not enough extra data for snapshot table entries) - Allow callers of bdrv_truncate() (etc.) to determine whether the file must be resized to the exact given size or whether it is OK for block devices not to shrink # gpg: Signature made Mon 28 Oct 2019 12:13:53 GMT # gpg: using RSA key 91BEB60A30DB3E8857D11829F407DB0061D5CF40 # gpg: issuer "mreitz@redhat.com" # gpg: Good signature from "Max Reitz <mreitz@redhat.com>" [full] # Primary key fingerprint: 91BE B60A 30DB 3E88 57D1 1829 F407 DB00 61D5 CF40 * remotes/maxreitz/tags/pull-block-2019-10-28: (69 commits) qemu-iotests: restrict 264 to qcow2 only Revert "qemu-img: Check post-truncation size" block: Pass truncate exact=true where reasonable block: Let format drivers pass @exact block: Evaluate @exact in protocol drivers block: Add @exact parameter to bdrv_co_truncate() block: Do not truncate file node when formatting block/cor: Drop cor_co_truncate() block: Handle filter truncation like native impl. iotests: Test qcow2's snapshot table handling iotests: Add peek_file* functions qcow2: Fix v3 snapshot table entry compliancy qcow2: Repair snapshot table with too many entries qcow2: Fix overly long snapshot tables qcow2: Keep track of the snapshot table length qcow2: Fix broken snapshot table entries qcow2: Add qcow2_check_fix_snapshot_table() qcow2: Separate qcow2_check_read_snapshot_table() qcow2: Write v3-compliant snapshot list on upgrade qcow2: Put qcow2_upgrade() into its own function ... Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
| * block: Evaluate @exact in protocol driversMax Reitz2019-10-281-1/+7
| | | | | | | | | | | | | | | | | | | | | | | | We have two protocol drivers that return success when trying to shrink a block device even though they cannot shrink it. This behavior is now only allowed with exact=false, so they should return an error with exact=true. Signed-off-by: Max Reitz <mreitz@redhat.com> Message-id: 20190918095144.955-6-mreitz@redhat.com Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com> Signed-off-by: Max Reitz <mreitz@redhat.com>
| * block: Add @exact parameter to bdrv_co_truncate()Max Reitz2019-10-281-1/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | We have two drivers (iscsi and file-posix) that (in some cases) return success from their .bdrv_co_truncate() implementation if the block device is larger than the requested offset, but cannot be shrunk. Some callers do not want that behavior, so this patch adds a new parameter that they can use to turn off that behavior. This patch just adds the parameter and lets the block/io.c and block/block-backend.c functions pass it around. All other callers always pass false and none of the implementations evaluate it, so that this patch does not change existing behavior. Future patches take care of that. Suggested-by: Maxim Levitsky <mlevitsk@redhat.com> Signed-off-by: Max Reitz <mreitz@redhat.com> Message-id: 20190918095144.955-5-mreitz@redhat.com Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com> Signed-off-by: Max Reitz <mreitz@redhat.com>
* | core: replace getpagesize() with qemu_real_host_page_sizeWei Yang2019-10-261-4/+5
|/ | | | | | | | | | | | | | | | | | | | | There are three page size in qemu: real host page size host page size target page size All of them have dedicate variable to represent. For the last two, we use the same form in the whole qemu project, while for the first one we use two forms: qemu_real_host_page_size and getpagesize(). qemu_real_host_page_size is defined to be a replacement of getpagesize(), so let it serve the role. [Note] Not fully tested for some arch or device. Signed-off-by: Wei Yang <richardw.yang@linux.intel.com> Message-Id: <20191013021145.16011-3-richardw.yang@linux.intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
* qapi: query-blockstat: add driver specific file-posix statsAnton Nefedov2019-10-101-0/+32
| | | | | | | | | | | | | A block driver can provide a callback to report driver-specific statistics. file-posix driver now reports discard statistics Signed-off-by: Anton Nefedov <anton.nefedov@virtuozzo.com> Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Acked-by: Markus Armbruster <armbru@redhat.com> Message-id: 20190923121737.83281-10-anton.nefedov@virtuozzo.com Signed-off-by: Max Reitz <mreitz@redhat.com>
* file-posix: account discard operationsAnton Nefedov2019-10-101-1/+21
| | | | | | | | | | | | | | | This will help to identify how many of the user-issued discard operations (accounted on a device level) have actually suceeded down on the host file (even though the numbers will not be exactly the same if non-raw format driver is used (e.g. qcow2 sending metadata discards)). Note that these numbers will not include discards triggered by write-zeroes + MAY_UNMAP calls. Signed-off-by: Anton Nefedov <anton.nefedov@virtuozzo.com> Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Message-id: 20190923121737.83281-9-anton.nefedov@virtuozzo.com Signed-off-by: Max Reitz <mreitz@redhat.com>
* file-posix: Fix has_write_zeroes after NO_FALLBACKKevin Wolf2019-09-101-3/+3
| | | | | | | | | | | | | If QEMU_AIO_NO_FALLBACK is given, we always return failure and don't even try to use the BLKZEROOUT ioctl. In this failure case, we shouldn't disable has_write_zeroes because we didn't learn anything about the ioctl. The next request might not set QEMU_AIO_NO_FALLBACK and we can still use the ioctl then. Fixes: 738301e1175 Reported-by: Eric Blake <eblake@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com>
* block/file-posix: Reduce xfsctl() useMax Reitz2019-09-101-76/+1Star
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch removes xfs_write_zeroes() and xfs_discard(). Both functions have been added just before the same feature was present through fallocate(): - fallocate() has supported PUNCH_HOLE for XFS since Linux 2.6.38 (March 2011); xfs_discard() was added in December 2010. - fallocate() has supported ZERO_RANGE for XFS since Linux 3.15 (June 2014); xfs_write_zeroes() was added in November 2013. Nowadays, all systems that qemu runs on should support both fallocate() features (RHEL 7's kernel does). xfsctl() is still useful for getting the request alignment for O_DIRECT, so this patch does not remove our dependency on it completely. Note that xfs_write_zeroes() had a bug: It calls ftruncate() when the file is shorter than the specified range (because ZERO_RANGE does not increase the file length). ftruncate() may yield and then discard data that parallel write requests have written past the EOF in the meantime. Dropping the function altogether fixes the bug. Suggested-by: Paolo Bonzini <pbonzini@redhat.com> Fixes: 50ba5b2d994853b38fed10e0841b119da0f8b8e5 Reported-by: Lukáš Doktor <ldoktor@redhat.com> Cc: qemu-stable@nongnu.org Signed-off-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Stefano Garzarella <sgarzare@redhat.com> Reviewed-by: John Snow <jsnow@redhat.com> Tested-by: Stefano Garzarella <sgarzare@redhat.com> Tested-by: John Snow <jsnow@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
* block: workaround for unaligned byte range in fallocate()Andrey Shinkevich2019-09-051-0/+7
| | | | | | | | | | | | | | | Revert the commit 118f99442d 'block/io.c: fix for the allocation failure' and use better error handling for file systems that do not support fallocate() for an unaligned byte range. Allow falling back to pwrite in case fallocate() returns EINVAL. Suggested-by: Kevin Wolf <kwolf@redhat.com> Suggested-by: Eric Blake <eblake@redhat.com> Signed-off-by: Andrey Shinkevich <andrey.shinkevich@virtuozzo.com> Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Denis V. Lunev <den@openvz.org> Message-Id: <1566913973-15490-1-git-send-email-andrey.shinkevich@virtuozzo.com> Signed-off-by: Eric Blake <eblake@redhat.com>
* file-posix: fix request_alignment typoStefan Hajnoczi2019-09-031-1/+1
| | | | | | | | | Fixes: a6b257a08e3d72219f03e461a52152672fec0612 ("file-posix: Handle undetectable alignment") Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Message-id: 20190827101328.4062-1-stefanha@redhat.com Reviewed-by: Thomas Huth <thuth@redhat.com> Signed-off-by: Max Reitz <mreitz@redhat.com>
* block: posix: Always allocate the first blockNir Soffer2019-09-031-0/+51
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When creating an image with preallocation "off" or "falloc", the first block of the image is typically not allocated. When using Gluster storage backed by XFS filesystem, reading this block using direct I/O succeeds regardless of request length, fooling alignment detection. In this case we fallback to a safe value (4096) instead of the optimal value (512), which may lead to unneeded data copying when aligning requests. Allocating the first block avoids the fallback. Since we allocate the first block even with preallocation=off, we no longer create images with zero disk size: $ ./qemu-img create -f raw test.raw 1g Formatting 'test.raw', fmt=raw size=1073741824 $ ls -lhs test.raw 4.0K -rw-r--r--. 1 nsoffer nsoffer 1.0G Aug 16 23:48 test.raw And converting the image requires additional cluster: $ ./qemu-img measure -f raw -O qcow2 test.raw required size: 458752 fully allocated size: 1074135040 When using format like vmdk with multiple files per image, we allocate one block per file: $ ./qemu-img create -f vmdk -o subformat=twoGbMaxExtentFlat test.vmdk 4g Formatting 'test.vmdk', fmt=vmdk size=4294967296 compat6=off hwversion=undefined subformat=twoGbMaxExtentFlat $ ls -lhs test*.vmdk 4.0K -rw-r--r--. 1 nsoffer nsoffer 2.0G Aug 27 03:23 test-f001.vmdk 4.0K -rw-r--r--. 1 nsoffer nsoffer 2.0G Aug 27 03:23 test-f002.vmdk 4.0K -rw-r--r--. 1 nsoffer nsoffer 353 Aug 27 03:23 test.vmdk I did quick performance test for copying disks with qemu-img convert to new raw target image to Gluster storage with sector size of 512 bytes: for i in $(seq 10); do rm -f dst.raw sleep 10 time ./qemu-img convert -f raw -O raw -t none -T none src.raw dst.raw done Here is a table comparing the total time spent: Type Before(s) After(s) Diff(%) --------------------------------------- real 530.028 469.123 -11.4 user 17.204 10.768 -37.4 sys 17.881 7.011 -60.7 We can see very clear improvement in CPU usage. Signed-off-by: Nir Soffer <nsoffer@redhat.com> Message-id: 20190827010528.8818-2-nsoffer@redhat.com Reviewed-by: Max Reitz <mreitz@redhat.com> Signed-off-by: Max Reitz <mreitz@redhat.com>
* block: Implement .bdrv_has_zero_init_truncate()Max Reitz2019-08-191-0/+1
| | | | | | | | | | | | | | | We need to implement .bdrv_has_zero_init_truncate() for every block driver that supports truncation and has a .bdrv_has_zero_init() implementation. Implement it the same way each driver implements .bdrv_has_zero_init(). This is at least not any more unsafe than what we had before. Signed-off-by: Max Reitz <mreitz@redhat.com> Message-id: 20190724171239.8764-5-mreitz@redhat.com Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com> Reviewed-by: Stefano Garzarella <sgarzare@redhat.com> Signed-off-by: Max Reitz <mreitz@redhat.com>
* block: fix NetBSD qemu-iotests failurePaolo Bonzini2019-08-171-2/+2
| | | | | | | | | | | | | | | | | | | Opening a block device on NetBSD has an additional step compared to other OSes, corresponding to raw_normalize_devicepath. The error message in that function is slightly different from that in raw_open_common and this was causing spurious failures in qemu-iotests. However, in general it is not important to know what exact step was failing, for example in the qemu-iotests case the error message contains the fairly unequivocal "No such file or directory" text from strerror. We can thus fix the failures by standardizing on a single error message for both raw_open_common and raw_normalize_devicepath; in fact, we can even use error_setg_file_open to make sure the error message is the same as in the rest of QEMU. Message-Id: <20190725095920.28419-1-pbonzini@redhat.com> Tested-by: Thomas Huth <thuth@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com> Signed-off-by: Thomas Huth <thuth@redhat.com>
* file-posix: Handle undetectable alignmentNir Soffer2019-08-161-11/+25
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | In some cases buf_align or request_alignment cannot be detected: 1. With Gluster, buf_align cannot be detected since the actual I/O is done on Gluster server, and qemu buffer alignment does not matter. Since we don't have alignment requirement, buf_align=1 is the best value. 2. With local XFS filesystem, buf_align cannot be detected if reading from unallocated area. In this we must align the buffer, but we don't know what is the correct size. Using the wrong alignment results in I/O error. 3. With Gluster backed by XFS, request_alignment cannot be detected if reading from unallocated area. In this case we need to use the correct alignment, and failing to do so results in I/O errors. 4. With NFS, the server does not use direct I/O, so both buf_align cannot be detected. In this case we don't need any alignment so we can use buf_align=1 and request_alignment=1. These cases seems to work when storage sector size is 512 bytes, because the current code starts checking align=512. If the check succeeds because alignment cannot be detected we use 512. But this does not work for storage with 4k sector size. To determine if we can detect the alignment, we probe first with align=1. If probing succeeds, maybe there are no alignment requirement (cases 1, 4) or we are probing unallocated area (cases 2, 3). Since we don't have any way to tell, we treat this as undetectable alignment. If probing with align=1 fails with EINVAL, but probing with one of the expected alignments succeeds, we know that we found a working alignment. Practically the alignment requirements are the same for buffer alignment, buffer length, and offset in file. So in case we cannot detect buf_align, we can use request alignment. If we cannot detect request alignment, we can fallback to a safe value. To use this logic, we probe first request alignment instead of buf_align. Here is a table showing the behaviour with current code (the value in parenthesis is the optimal value). Case Sector buf_align (opt) request_alignment (opt) result ====================================================================== 1 512 512 (1) 512 (512) OK 1 4096 512 (1) 4096 (4096) FAIL ---------------------------------------------------------------------- 2 512 512 (512) 512 (512) OK 2 4096 512 (4096) 4096 (4096) FAIL ---------------------------------------------------------------------- 3 512 512 (1) 512 (512) OK 3 4096 512 (1) 512 (4096) FAIL ---------------------------------------------------------------------- 4 512 512 (1) 512 (1) OK 4 4096 512 (1) 512 (1) OK Same cases with this change: Case Sector buf_align (opt) request_alignment (opt) result ====================================================================== 1 512 512 (1) 512 (512) OK 1 4096 4096 (1) 4096 (4096) OK ---------------------------------------------------------------------- 2 512 512 (512) 512 (512) OK 2 4096 4096 (4096) 4096 (4096) OK ---------------------------------------------------------------------- 3 512 4096 (1) 4096 (512) OK 3 4096 4096 (1) 4096 (4096) OK ---------------------------------------------------------------------- 4 512 4096 (1) 4096 (1) OK 4 4096 4096 (1) 4096 (1) OK I tested that provisioning VMs and copying disks on local XFS and Gluster with 4k bytes sector size work now, resolving bugs [1],[2]. I tested also on XFS, NFS, Gluster with 512 bytes sector size. [1] https://bugzilla.redhat.com/1737256 [2] https://bugzilla.redhat.com/1738657 Signed-off-by: Nir Soffer <nsoffer@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
* file-posix: Use max transfer length/segment count only for SCSI passthroughMaxim Levitsky2019-07-121-26/+28
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Regular kernel block devices (/dev/sda*, /dev/nvme*, etc) don't have max segment size/max segment count hardware requirements exposed to the userspace, but rather the kernel block layer takes care to split the incoming requests that violate these requirements. Allowing the kernel to do the splitting allows qemu to avoid various overheads that arise otherwise from this. This is especially visible in nbd server, exposing as a raw file, a mostly empty qcow2 image over the net. In this case most of the reads by the remote user won't even hit the underlying kernel block device, and therefore most of the overhead will be in the nbd traffic which increases significantly with lower max transfer size. In addition to that even for local block device access the peformance improves a bit due to less traffic between qemu and the kernel when large transfer sizes are used (e.g for image conversion) More info can be found at: https://bugzilla.redhat.com/show_bug.cgi?id=1647104 Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Pankaj Gupta <pagupta@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
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