update Documentation/filesystems/Locking

The rules for locking in many superblock operations has changed
significantly, so update the documentation for it.  Also correct some
older updates and ommissions.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Christoph Hellwig 2009-06-19 20:22:37 +02:00 committed by Al Viro
parent f6cc746bbb
commit 7e325d3a6b

View file

@ -109,27 +109,28 @@ prototypes:
locking rules:
All may block.
BKL s_lock s_umount
alloc_inode: no no no
destroy_inode: no
dirty_inode: no (must not sleep)
write_inode: no
drop_inode: no !!!inode_lock!!!
delete_inode: no
put_super: yes yes no
write_super: no yes read
sync_fs: no no read
freeze_fs: ?
unfreeze_fs: ?
statfs: no no no
remount_fs: yes yes maybe (see below)
clear_inode: no
umount_begin: yes no no
show_options: no (vfsmount->sem)
quota_read: no no no (see below)
quota_write: no no no (see below)
None have BKL
s_umount
alloc_inode:
destroy_inode:
dirty_inode: (must not sleep)
write_inode:
drop_inode: !!!inode_lock!!!
delete_inode:
put_super: write
write_super: read
sync_fs: read
freeze_fs: read
unfreeze_fs: read
statfs: no
remount_fs: maybe (see below)
clear_inode:
umount_begin: no
show_options: no (namespace_sem)
quota_read: no (see below)
quota_write: no (see below)
->remount_fs() will have the s_umount lock if it's already mounted.
->remount_fs() will have the s_umount exclusive lock if it's already mounted.
When called from get_sb_single, it does NOT have the s_umount lock.
->quota_read() and ->quota_write() functions are both guaranteed to
be the only ones operating on the quota file by the quota code (via