diff options
Diffstat (limited to 'Documentation/filesystems/porting')
| -rw-r--r-- | Documentation/filesystems/porting | 27 |
1 files changed, 24 insertions, 3 deletions
diff --git a/Documentation/filesystems/porting b/Documentation/filesystems/porting index 6e29954851a2..7f8861d341ea 100644 --- a/Documentation/filesystems/porting +++ b/Documentation/filesystems/porting @@ -400,10 +400,31 @@ a file off. -- [mandatory] - --- -[mandatory] ->get_sb() is gone. Switch to use of ->mount(). Typically it's just a matter of switching from calling get_sb_... to mount_... and changing the function type. If you were doing it manually, just switch from setting ->mnt_root to some pointer to returning that pointer. On errors return ERR_PTR(...). + +-- +[mandatory] + ->permission(), generic_permission() and ->check_acl() have lost flags +argument; instead of passing IPERM_FLAG_RCU we add MAY_NOT_BLOCK into mask. + generic_permission() has also lost the check_acl argument; if you want +non-NULL to be used for that inode, put it into ->i_op->check_acl. + +-- +[mandatory] + If you implement your own ->llseek() you must handle SEEK_HOLE and +SEEK_DATA. You can hanle this by returning -EINVAL, but it would be nicer to +support it in some way. The generic handler assumes that the entire file is +data and there is a virtual hole at the end of the file. So if the provided +offset is less than i_size and SEEK_DATA is specified, return the same offset. +If the above is true for the offset and you are given SEEK_HOLE, return the end +of the file. If the offset is i_size or greater return -ENXIO in either case. + +[mandatory] + If you have your own ->fsync() you must make sure to call +filemap_write_and_wait_range() so that all dirty pages are synced out properly. +You must also keep in mind that ->fsync() is not called with i_mutex held +anymore, so if you require i_mutex locking you must make sure to take it and +release it yourself. |