On Wed, Jun 21, 2017 at 06:49:36PM -0700, Tahsin Erdogan wrote: > New ea_inode feature allows putting large xattr values into external > inodes. struct ext4_xattr_entry and the attribute name however have to > remain in the inode extra space or external attribute block. Once that > space is exhausted, no further entries can be added. Some of that space > could also be used by values that fit in there at the time of addition. > > So, a single xattr entry whose value barely fits in the external block > could prevent further entries being added. > > To mitigate the problem, this patch introduces a notion of reserve in > the > external attribute block that cannot be used by value data. This reserve > is enforced when ea_inode feature is enabled. The amount of reserve is > arbitrarily chosen to be min(block_size/8, 1024). The table below shows > how much space is reserved for each block size and the guaranteed > mininum > number of entries that can be placed in the external attribute block. > > block size reserved bytes entries (name length = 16) > 1k 128 3 > 2k 256 7 > 4k 512 15 > 8k 1024 31 > 16k 1024 31 > 32k 1024 31 > 64k 1024 31 > > Signed-off-by: Tahsin Erdogan <tahsin@xxxxxxxxxx> Thanks, applied. - Ted
