SB_START_PAGEFAULT(9) The Linux VFS SB_START_PAGEFAULT(9)NAMEsb_start_pagefault - get write access to a superblock from a page fault
SYNOPSIS
void sb_start_pagefault(struct super_block * sb);
ARGUMENTS
sb
the super we write to
DESCRIPTION
When a process starts handling write page fault, it should embed the
operation into sb_start_pagefault - sb_end_pagefault pair to get
exclusion against file system freezing. This is needed since the page
fault is going to dirty a page. This function increments number of
running page faults preventing freezing. If the file system is already
frozen, the function waits until the file system is thawed.
Since page fault freeze protection behaves as a lock, users have to
preserve ordering of freeze protection and other filesystem locks. It
is advised to put sb_start_pagefault close to mmap_sem in lock
ordering. Page fault
HANDLING CODE IMPLIES LOCK DEPENDENCY
mmap_sem -> sb_start_pagefaultCOPYRIGHTKernel Hackers Manual 2.6. November 2013 SB_START_PAGEFAULT(9)