On Mon, Mar 25, 2024 at 10:36:21AM +0000, Srivathsa Dara wrote: > According to the mke2fs man page, the supported cluster-size values > for an ext4 filesystem are 2048 to 256M bytes. However, this is not > the case. > > When mkfs is run to create a filesystem with following specifications: > * 1k blocksize and cluster-size greater than 32M > * 2k blocksize and cluster-size greater than 64M > * 4k blocksize and cluster-size greater than 128M > mkfs fails with "Invalid argument passed to ext2 library while trying > to create journal" error. In general, when the cluster-size to blocksize > ratio is greater than 32k, mkfs fails with this error. > > Went through the code and found out that the function > `ext2fs_new_range()` is the source of this error. This is because when > the cluster-size to blocksize ratio exceeds 32k, the length argument > to the function `ext2fs_new_range()` results in 0. Hence, the error. > > This patch corrects the valid cluster-size values. > --- > misc/mke2fs.8.in | 6 +++--- > 1 file changed, 3 insertions(+), 3 deletions(-) > > diff --git a/misc/mke2fs.8.in b/misc/mke2fs.8.in > index 30f97bb5..8194cc41 100644 > --- a/misc/mke2fs.8.in > +++ b/misc/mke2fs.8.in > @@ -232,9 +232,9 @@ test is used instead of a fast read-only test. > .TP > .B \-C " cluster-size" > Specify the size of cluster in bytes for file systems using the bigalloc > -feature. Valid cluster-size values are from 2048 to 256M bytes per > -cluster. This can only be specified if the bigalloc feature is > -enabled. (See the > +feature. Valid cluster-size values range from 2 to 32768 times the > +filesystem blocksize per cluster. This can only be specified if the I think it's redundant to say cluster twice in this sentence: "The cluster size must be a power of two between 2 and 32768 times the filesystem block size." It's also worth mentioning that mkfs rounds the parameter down to the nearest power of two, e.g. "-C 20k" gets you a 16k cluster size. --D > +bigalloc feature is enabled. (See the > .B ext4 (5) > man page for more details about bigalloc.) The default cluster size if > bigalloc is enabled is 16 times the block size. > -- > 2.39.3 > >
