On Sun, 19 Dec 2010, NAKAJIMA Yoshihiro wrote:
> Hello LFS developers,
>
>
> When vmlocking2 was merged, lock and unlock were moved out of
> LFS_{SET,CLR}_UINO.
>
> : % diff -U4 lfs.h:1.{122,123} | sed -n 94,104p
> : #define LFS_SET_UINO(ip, flags) do {
> \
> : - simple_lock(&(ip)->i_lfs->lfs_interlock); \
> : if (((flags) & IN_ACCESSED) && !((ip)->i_flag & IN_ACCESSED)) \
> : ++(ip)->i_lfs->lfs_uinodes; \
> : if (((flags) & IN_CLEANING) && !((ip)->i_flag & IN_CLEANING)) \
> : ++(ip)->i_lfs->lfs_uinodes; \
> : if (((flags) & IN_MODIFIED) && !((ip)->i_flag & IN_MODIFIED)) \
> : ++(ip)->i_lfs->lfs_uinodes; \
> : (ip)->i_flag |= (flags); \
> : - simple_unlock(&(ip)->i_lfs->lfs_interlock); \
> : } while (0)
>
> I guess the lock protects lfs_uinodes, when IN_ACCESSED, IN_CLEANING
> or IN_MODIFIED are set.
>
> If it is right, a lock is unnecessary and some locks are missing. See
> attached patch.
Looks reasonable. You should definitely add a comment somewhere
indicating the uino is protected by the lfs_lock. Locking protocols must
be documented or they are guaranteed to be broken. Have you tested it
under load?
Eduardo
