On 4/1/25 3:33 PM, Eric Sandeen wrote: > On 3/31/25 3:31 AM, Chao Yu wrote: >> On 3/29/25 12:18, Eric Sandeen wrote: >>> I was working on next steps for this, and I have a followup question. >>> >>> Today, several mount options are simply ignored if the on-disk format >>> does not support them. For example: >>> >>> case Opt_compress_mode: >>> if (!f2fs_sb_has_compression(sbi)) { >>> f2fs_info(sbi, "Image doesn't support >>> compression"); >>> break; >>> } >>> name = match_strdup(&args[0]); >>> if (!name) >>> return -ENOMEM; >>> if (!strcmp(name, "fs")) { >>> F2FS_OPTION(sbi).compress_mode = >>> COMPR_MODE_FS; >>> } else if (!strcmp(name, "user")) { >>> F2FS_OPTION(sbi).compress_mode = >>> COMPR_MODE_USER; >>> } else { >>> kfree(name); >>> return -EINVAL; >>> } >>> kfree(name); >>> break; >>> >>> so if f2fs_sb_has_compression() is not true, then the option is ignored >>> without >>> any validation. >>> >>> in other words, "mount -o compress_mode=nope ..." will succeed if the >>> feature >>> is disabled on the filesystem. >>> >>> If I move the f2fs_sb_has_compression() check to later for the new mount >>> API, >>> then "mount -o compress_mode=nope ..." will start failing for all images. >>> Is >>> this acceptable? It seems wise to reject invalid options rather than ignore >>> them, >>> even if they are incompatible with the format, but this would be a behavior >>> change. >> >> I'm fine w/ this change. IIRC, I haven't saw above use case, otherwise user >> should stop passing invalid mount option to f2fs. > > Great, I will proceed with this. It will make the conversion simpler (but may > make testing/validation more difficult, as behavior will change with invalid > input).
FYI - I don't think I will be able to complete this conversion task myself - f2fs is by far the most difficult conversion I've encountered, and my time for these sorts of projects is sadly limited. I do have one more patch series that moves a lot of the on-disk feature checking out of option parsing, and perhaps I will send it as an example at least. But I think it may be time to ask the f2fs experts to take over this effort, because I'm just not getting through it on my own. (We are down to only a small handful of filesystems left - in fact, I think only bfs, 9p, and f2fs, that don't have patches anywhere. So it would be really great to get some help on this.) Thanks, -Eric > -Eric > >> Thanks, _______________________________________________ Linux-f2fs-devel mailing list Linux-f2fs-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel