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From: Omar Sandoval <osandov@osandov.com>
To: Nikolay Borisov <nborisov@suse.com>
Cc: linux-btrfs@vger.kernel.org, kernel-team@fb.com,
	linux-fsdevel@vger.kernel.org, Al Viro <viro@zeniv.linux.org.uk>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	linux-api@vger.kernel.org
Subject: Re: [PATCH v10 04/14] btrfs: add ram_bytes and offset to btrfs_ordered_extent
Date: Fri, 20 Aug 2021 10:43:32 -0700	[thread overview]
Message-ID: <YR/pxN3HTs36wmfD@relinquished.localdomain> (raw)
In-Reply-To: <e69e1e3c-6338-d0e4-626a-a2fa9886de7a@suse.com>

On Fri, Aug 20, 2021 at 11:34:17AM +0300, Nikolay Borisov wrote:
> 
> 
> On 18.08.21 г. 0:06, Omar Sandoval wrote:
> > From: Omar Sandoval <osandov@fb.com>
> > 
> > Currently, we only create ordered extents when ram_bytes == num_bytes
> > and offset == 0. However, RWF_ENCODED writes may create extents which
> > only refer to a subset of the full unencoded extent, so we need to plumb
> 
> Can you give an example of such a case?

It happens whenever we have bookend extents. Here's an easy example:

$ dd if=/dev/zero of=file bs=12k count=1
1+0 records in
1+0 records out
12288 bytes (12 kB, 12 KiB) copied, 0.000202106 s, 60.8 MB/s
$ sync
$ truncate -s 8k file
$ sync
$ sudo ~/repos/osandov-linux/scripts/btrfs_map_physical ./file | column -ts$'\t'
FILE OFFSET  FILE SIZE  EXTENT OFFSET  EXTENT TYPE               LOGICAL SIZE  LOGICAL OFFSET  PHYSICAL SIZE  DEVID  PHYSICAL OFFSET
0            8192       0              regular,compression=zstd  12288         217173213184    4096           1      217173213184

The decompressed data is 12k, but we only use 8k for the file.

  reply	other threads:[~2021-08-20 17:43 UTC|newest]

Thread overview: 45+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-08-17 21:06 [PATCH v10 00/14] btrfs: add ioctls and send/receive support for reading/writing compressed data Omar Sandoval
2021-08-17 21:06 ` [PATCH v10 01/14] fs: export rw_verify_area() Omar Sandoval
2021-08-17 21:06 ` [PATCH v10 02/14] fs: export variant of generic_write_checks without iov_iter Omar Sandoval
2021-08-20  7:59   ` Nikolay Borisov
2021-08-20 17:31     ` Omar Sandoval
2021-08-17 21:06 ` [PATCH v10 03/14] btrfs: don't advance offset for compressed bios in btrfs_csum_one_bio() Omar Sandoval
2021-08-20  8:08   ` Nikolay Borisov
2021-08-20 17:37     ` Omar Sandoval
2021-08-17 21:06 ` [PATCH v10 04/14] btrfs: add ram_bytes and offset to btrfs_ordered_extent Omar Sandoval
2021-08-20  8:34   ` Nikolay Borisov
2021-08-20 17:43     ` Omar Sandoval [this message]
2021-08-17 21:06 ` [PATCH v10 05/14] btrfs: support different disk extent size for delalloc Omar Sandoval
2021-08-17 21:06 ` [PATCH v10 06/14] btrfs: optionally extend i_size in cow_file_range_inline() Omar Sandoval
2021-08-20  8:51   ` Nikolay Borisov
2021-08-20  9:13     ` Qu Wenruo
2021-08-20 18:11       ` Omar Sandoval
2021-08-21  1:11         ` Qu Wenruo
2021-08-23 18:16           ` Omar Sandoval
2021-08-23 23:32             ` Qu Wenruo
2021-08-23 23:46               ` Omar Sandoval
2021-08-17 21:06 ` [PATCH v10 07/14] btrfs: add definitions + documentation for encoded I/O ioctls Omar Sandoval
2021-08-20  8:56   ` Nikolay Borisov
2021-08-20 17:48     ` Omar Sandoval
2021-08-17 21:06 ` [PATCH v10 08/14] btrfs: add BTRFS_IOC_ENCODED_READ Omar Sandoval
2021-08-20 12:30   ` Nikolay Borisov
2021-08-20 17:58     ` Omar Sandoval
2021-08-17 21:06 ` [PATCH v10 09/14] btrfs: add BTRFS_IOC_ENCODED_WRITE Omar Sandoval
2021-08-20 13:44   ` Nikolay Borisov
2021-08-20 17:59     ` Omar Sandoval
2021-08-17 21:06 ` [PATCH v10 10/14] btrfs: add send stream v2 definitions Omar Sandoval
2021-08-17 21:06 ` [PATCH v10 11/14] btrfs: send: write larger chunks when using stream v2 Omar Sandoval
2021-08-17 21:06 ` [PATCH v10 12/14] btrfs: send: allocate send buffer with alloc_page() and vmap() for v2 Omar Sandoval
2021-08-17 21:06 ` [PATCH v10 13/14] btrfs: send: send compressed extents with encoded writes Omar Sandoval
2021-08-17 21:06 ` [PATCH v10 14/14] btrfs: send: enable support for stream v2 and compressed writes Omar Sandoval
2021-08-17 21:06 ` [PATCH v10 01/10] btrfs-progs: receive: support v2 send stream larger tlv_len Omar Sandoval
2021-08-17 21:06 ` [PATCH v10 02/10] btrfs-progs: receive: dynamically allocate sctx->read_buf Omar Sandoval
2021-08-17 21:06 ` [PATCH v10 03/10] btrfs-progs: receive: support v2 send stream DATA tlv format Omar Sandoval
2021-08-17 21:06 ` [PATCH v10 04/10] btrfs-progs: receive: add send stream v2 cmds and attrs to send.h Omar Sandoval
2021-08-17 21:06 ` [PATCH v10 05/10] btrfs-progs: receive: process encoded_write commands Omar Sandoval
2021-08-17 21:06 ` [PATCH v10 06/10] btrfs-progs: receive: encoded_write fallback to explicit decode and write Omar Sandoval
2021-08-18 18:07   ` Omar Sandoval
2021-08-17 21:06 ` [PATCH v10 07/10] btrfs-progs: receive: process fallocate commands Omar Sandoval
2021-08-17 21:06 ` [PATCH v10 08/10] btrfs-progs: receive: process setflags ioctl commands Omar Sandoval
2021-08-17 21:06 ` [PATCH v10 09/10] btrfs-progs: send: stream v2 ioctl flags Omar Sandoval
2021-08-17 21:06 ` [PATCH v10 10/10] btrfs-progs: receive: add tests for basic encoded_write send/receive Omar Sandoval

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