1.. SPDX-License-Identifier: GPL-2.0 2 3Large Extended Attribute Values 4------------------------------- 5 6To enable ext4 to store extended attribute values that do not fit in the 7inode or in the single extended attribute block attached to an inode, 8the EA_INODE feature allows us to store the value in the data blocks of 9a regular file inode. This “EA inode” is linked only from the extended 10attribute name index and must not appear in a directory entry. The 11inode's i_atime field is used to store a checksum of the xattr value; 12and i_ctime/i_version store a 64-bit reference count, which enables 13sharing of large xattr values between multiple owning inodes. For 14backward compatibility with older versions of this feature, the 15i_mtime/i_generation *may* store a back-reference to the inode number 16and i_generation of the **one** owning inode (in cases where the EA 17inode is not referenced by multiple inodes) to verify that the EA inode 18is the correct one being accessed. 19