Hello, On 04/06/2023 14:37:52+0200, Charles-Antoine Couret via lists.openembedded.org wrote: > In case of fixed partitionning where the rootfs partition can't exceed an > amount of bytes, there is currently no automatic and no generic way to have > this requirement met in any case. > > Until now, ROOTFS_SIZE value got from directory_size() does not takes into > account > the size of required metadata for the filesystem itself (and does not work > well > for other block size than 4k BTW). > Obviously it's a difficult task which depends on rootfs size and filesystem > type. > > The workaround was to set IMAGE_OVERHEAD_FACTOR and IMAGE_ROOTFS_EXTRA_SPACE > to add the required extra margins. But when the final rootfs is closed to the > maximum size, it's difficult to adjust them correctly And if you remove > or add new recipes in your image, you've to recompute these margins to have > enough > space for these metadata when the rootfs is small, and to not have too big > final > file when the rootfs is big. > > It's cumbersome and error prone to just have a build failure when the final > output > can't be flashed into the partition. > > The solution is to follow how it's implemented in buildroot by having a > specific variable, here IMAGE_FILE_MAXSIZE, to create the final sparse file > and trying to fill it with the content of rootfs. If there is enough space, > margins are well compressed and does not consume space in the filesystem. > If there is no enough space, an error is triggered to warm the developer > before > trying to use it in the device. > > If IMAGE_FILE_MAXSIZE is not set, the idea is to keep the previous behaviour > for compatibility reason and to met other requirements.
It would be great if you could add test cases that ensure that the generated images are indeed fitting the size. > > Charles-Antoine Couret (3): > image_types: use IMAGE_FILE_MAXSIZE variable for ext2/3/4 image types > image_types: use IMAGE_FILE_MAXSIZE variable for btrfs image types > image_types: use IMAGE_FILE_MAXSIZE variable for f2fs image types > > meta/classes-recipe/image_types.bbclass | 34 +++++++++++++++++++------ > 1 file changed, 26 insertions(+), 8 deletions(-) > > -- > 2.40.1 > > > > -- Alexandre Belloni, co-owner and COO, Bootlin Embedded Linux and Kernel engineering https://bootlin.com
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