[LU-6030] cleanup for ldiskfs patches

Related — Tue, 11 Aug 2015 06:44:49 +0000

Some ldiskfs patch need cleanup. From comments in http://review.whamcloud.com/#/c/10249/21 and http://review.whamcloud.com/#/c/10249/27:

ext4-extents-mount-option.patch: We format the OST with the EXT4_FEATURE_INCOMPAT_EXTENTS, and avoid it for the MDT. At most we would need to have a dummy mount option that accepts the "-o extents" option from Lustre (to avoid ~~LU-5425~~), and returns an error at mount time if INCOMPAT_EXTENTS is not already set. It would be possible to delete the whole patch by removing the "extents" option from the mount options in osd_mount()
ext4-misc.patch: It would be possible to remove the stub "mballoc", "iopen", "noiopen", "iopen_nopriv" mount option handling by removing those strings from the mount options in osd_mount()
ext4-fiemap.patch: this patch can be removed entirely, even from older RHEL6 kernels. ext4_fiemap() is accessible via ext4_file_inode_operations, so we could just call inode->i_op->fiemap(), and move the rest of the code into osd-ldiskfs/osd-fiemap.c
ext4-nocmtime.patch: this could be simplified by changing only ext4_current_time(inode) to return inode->i_ctime if NOCMTIME is set on the inode
ext4-pdirops.patch: it would be nice to split this into two separate patches. One for implementing 3-level htree and EXT4_FEATURE_INCOMPAT_LARGEDIR, and the other for pdirops. The 3-level htree LARGEDIR feature might be accepted upstream, while pdirops/htree_lock is harder since it has no VFS interface
ext4-pdirops.patch: remove i_append_sem and use i_data_sem or xattr_sem (if possible, not sure if there would be deadlocks in some code path)
ext4-max-dir-size.patch: add deprecation warning for max_dir_size /sysfs entry if used

Whamcloud Community JIRA

[LU-6030] cleanup for ldiskfs patches