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| author | Hanna Czenczek <hreitz@redhat.com> | 2023-02-27 11:47:24 +0100 |
|---|---|---|
| committer | Kevin Wolf <kwolf@redhat.com> | 2023-03-10 15:14:46 +0100 |
| commit | 1703eb1c27a6010ff33d5add2d76aadc9b2777bd (patch) | |
| tree | acd0f4c0d0842e9c8b9288687a037b27de529e1b | |
| parent | ee59483267de29056b5b2ee2421ef3844e5c9932 (diff) | |
| download | focaccia-qemu-1703eb1c27a6010ff33d5add2d76aadc9b2777bd.tar.gz focaccia-qemu-1703eb1c27a6010ff33d5add2d76aadc9b2777bd.zip | |
block/fuse: Let PUNCH_HOLE write zeroes
fallocate(2) says about PUNCH_HOLE: "After a successful call, subsequent reads from this range will return zeros." As it is, PUNCH_HOLE is implemented as a call to blk_pdiscard(), which does not guarantee this. We must call blk_pwrite_zeroes() instead. The difference to ZERO_RANGE is that we pass the `BDRV_REQ_MAY_UNMAP | BDRV_REQ_NO_FALLBACK` flags to the call -- the storage is supposed to be unmapped, and a slow fallback by actually writing zeroes as data is not allowed. Closes: https://gitlab.com/qemu-project/qemu/-/issues/1507 Signed-off-by: Hanna Czenczek <hreitz@redhat.com> Message-Id: <20230227104725.33511-2-hreitz@redhat.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Diffstat (limited to '')
| -rw-r--r-- | block/export/fuse.c | 11 |
1 files changed, 10 insertions, 1 deletions
diff --git a/block/export/fuse.c b/block/export/fuse.c index e5fc4af165..06fa41079e 100644 --- a/block/export/fuse.c +++ b/block/export/fuse.c @@ -673,7 +673,16 @@ static void fuse_fallocate(fuse_req_t req, fuse_ino_t inode, int mode, do { int size = MIN(length, BDRV_REQUEST_MAX_BYTES); - ret = blk_pdiscard(exp->common.blk, offset, size); + ret = blk_pwrite_zeroes(exp->common.blk, offset, size, + BDRV_REQ_MAY_UNMAP | BDRV_REQ_NO_FALLBACK); + if (ret == -ENOTSUP) { + /* + * fallocate() specifies to return EOPNOTSUPP for unsupported + * operations + */ + ret = -EOPNOTSUPP; + } + offset += size; length -= size; } while (ret == 0 && length > 0); |