We decided to request the latest three patches to be merged into this
merge window while it's still open. 1. The first patch adds a new function to lockref: lockref_put_not_zero 2. The second patch fixes GFS2's glock dump code so it uses the new lockref function. This fixes a problem whereby lock dumps could miss glocks. 3. I made a minor patch to update some comments and fix the lock ordering text in our gfs2-glocks.txt Documentation file. -----BEGIN PGP SIGNATURE----- iQEcBAABAgAGBQJaz6pdAAoJENeLYdPf93o71wMH/0cEo34xWiScRM07EgLmZZ3q YXMvpTvrwK+9i2u8anxiX1smezHeS+7jPrYOG8AGu3IZvKYGTDOwoIY9pxESy5gs 1Rf60s6pPE/dkTSqPaNNuBxPrM1yVyRWOPx04LxC5BCXhsS/6U2RS9ElxGDe7Nyq P66z1wfm63+erDR7mKSuOL3Ejtglj2EPcrAupaBlRS0wjdUQ9ORyrZBpT6JMOWqd HWjchrzWVAqx+iyLHlKZjTyPHsPaUBaj1fuv/Vcgu5sJmEJ9mF4s/GQTdwIzi8ip ByD7MfilyrT7dxRm1uw8OJ7TvqNeaCtxsyNGGBOlSx81s/pk5Vhs8bevnczNvi8= =jWsi -----END PGP SIGNATURE----- Merge tag 'gfs2-4.17.fixes2' of git://git.kernel.org/pub/scm/linux/kernel/git/gfs2/linux-gfs2 Pull more gfs2 updates from Bob Peterson: "We decided to request the latest three patches to be merged into this merge window while it's still open. - The first patch adds a new function to lockref: lockref_put_not_zero - The second patch fixes GFS2's glock dump code so it uses the new lockref function. This fixes a problem whereby lock dumps could miss glocks. - I made a minor patch to update some comments and fix the lock ordering text in our gfs2-glocks.txt Documentation file" * tag 'gfs2-4.17.fixes2' of git://git.kernel.org/pub/scm/linux/kernel/git/gfs2/linux-gfs2: GFS2: Minor improvements to comments and documentation gfs2: Stop using rhashtable_walk_peek lockref: Add lockref_put_not_zero
This commit is contained in:
commit
4ac1800f81
|
@ -100,14 +100,15 @@ indicates that it is caching uptodate data.
|
|||
|
||||
Glock locking order within GFS2:
|
||||
|
||||
1. i_mutex (if required)
|
||||
1. i_rwsem (if required)
|
||||
2. Rename glock (for rename only)
|
||||
3. Inode glock(s)
|
||||
(Parents before children, inodes at "same level" with same parent in
|
||||
lock number order)
|
||||
4. Rgrp glock(s) (for (de)allocation operations)
|
||||
5. Transaction glock (via gfs2_trans_begin) for non-read operations
|
||||
6. Page lock (always last, very important!)
|
||||
6. i_rw_mutex (if required)
|
||||
7. Page lock (always last, very important!)
|
||||
|
||||
There are two glocks per inode. One deals with access to the inode
|
||||
itself (locking order as above), and the other, known as the iopen
|
||||
|
|
|
@ -1744,7 +1744,7 @@ do_grow_qunlock:
|
|||
* @newsize: the size to make the file
|
||||
*
|
||||
* The file size can grow, shrink, or stay the same size. This
|
||||
* is called holding i_mutex and an exclusive glock on the inode
|
||||
* is called holding i_rwsem and an exclusive glock on the inode
|
||||
* in question.
|
||||
*
|
||||
* Returns: errno
|
||||
|
|
|
@ -1923,28 +1923,37 @@ void gfs2_glock_exit(void)
|
|||
|
||||
static void gfs2_glock_iter_next(struct gfs2_glock_iter *gi, loff_t n)
|
||||
{
|
||||
if (n == 0)
|
||||
gi->gl = rhashtable_walk_peek(&gi->hti);
|
||||
else {
|
||||
gi->gl = rhashtable_walk_next(&gi->hti);
|
||||
n--;
|
||||
struct gfs2_glock *gl = gi->gl;
|
||||
|
||||
if (gl) {
|
||||
if (n == 0)
|
||||
return;
|
||||
if (!lockref_put_not_zero(&gl->gl_lockref))
|
||||
gfs2_glock_queue_put(gl);
|
||||
}
|
||||
for (;;) {
|
||||
if (IS_ERR_OR_NULL(gi->gl)) {
|
||||
if (!gi->gl)
|
||||
return;
|
||||
if (PTR_ERR(gi->gl) != -EAGAIN) {
|
||||
gi->gl = NULL;
|
||||
return;
|
||||
gl = rhashtable_walk_next(&gi->hti);
|
||||
if (IS_ERR_OR_NULL(gl)) {
|
||||
if (gl == ERR_PTR(-EAGAIN)) {
|
||||
n = 1;
|
||||
continue;
|
||||
}
|
||||
n = 0;
|
||||
} else if (gi->sdp == gi->gl->gl_name.ln_sbd &&
|
||||
!__lockref_is_dead(&gi->gl->gl_lockref)) {
|
||||
if (!n--)
|
||||
break;
|
||||
gl = NULL;
|
||||
break;
|
||||
}
|
||||
if (gl->gl_name.ln_sbd != gi->sdp)
|
||||
continue;
|
||||
if (n <= 1) {
|
||||
if (!lockref_get_not_dead(&gl->gl_lockref))
|
||||
continue;
|
||||
break;
|
||||
} else {
|
||||
if (__lockref_is_dead(&gl->gl_lockref))
|
||||
continue;
|
||||
n--;
|
||||
}
|
||||
gi->gl = rhashtable_walk_next(&gi->hti);
|
||||
}
|
||||
gi->gl = gl;
|
||||
}
|
||||
|
||||
static void *gfs2_glock_seq_start(struct seq_file *seq, loff_t *pos)
|
||||
|
@ -1988,7 +1997,6 @@ static void gfs2_glock_seq_stop(struct seq_file *seq, void *iter_ptr)
|
|||
{
|
||||
struct gfs2_glock_iter *gi = seq->private;
|
||||
|
||||
gi->gl = NULL;
|
||||
rhashtable_walk_stop(&gi->hti);
|
||||
}
|
||||
|
||||
|
@ -2076,7 +2084,8 @@ static int gfs2_glocks_release(struct inode *inode, struct file *file)
|
|||
struct seq_file *seq = file->private_data;
|
||||
struct gfs2_glock_iter *gi = seq->private;
|
||||
|
||||
gi->gl = NULL;
|
||||
if (gi->gl)
|
||||
gfs2_glock_put(gi->gl);
|
||||
rhashtable_walk_exit(&gi->hti);
|
||||
return seq_release_private(inode, file);
|
||||
}
|
||||
|
|
|
@ -825,7 +825,7 @@ static int init_inodes(struct gfs2_sbd *sdp, int undo)
|
|||
goto fail_rindex;
|
||||
}
|
||||
/*
|
||||
* i_mutex on quota files is special. Since this inode is hidden system
|
||||
* i_rwsem on quota files is special. Since this inode is hidden system
|
||||
* file, we are safe to define locking ourselves.
|
||||
*/
|
||||
lockdep_set_class(&sdp->sd_quota_inode->i_rwsem,
|
||||
|
|
|
@ -37,6 +37,7 @@ struct lockref {
|
|||
extern void lockref_get(struct lockref *);
|
||||
extern int lockref_put_return(struct lockref *);
|
||||
extern int lockref_get_not_zero(struct lockref *);
|
||||
extern int lockref_put_not_zero(struct lockref *);
|
||||
extern int lockref_get_or_lock(struct lockref *);
|
||||
extern int lockref_put_or_lock(struct lockref *);
|
||||
|
||||
|
|
|
@ -80,6 +80,34 @@ int lockref_get_not_zero(struct lockref *lockref)
|
|||
}
|
||||
EXPORT_SYMBOL(lockref_get_not_zero);
|
||||
|
||||
/**
|
||||
* lockref_put_not_zero - Decrements count unless count <= 1 before decrement
|
||||
* @lockref: pointer to lockref structure
|
||||
* Return: 1 if count updated successfully or 0 if count would become zero
|
||||
*/
|
||||
int lockref_put_not_zero(struct lockref *lockref)
|
||||
{
|
||||
int retval;
|
||||
|
||||
CMPXCHG_LOOP(
|
||||
new.count--;
|
||||
if (old.count <= 1)
|
||||
return 0;
|
||||
,
|
||||
return 1;
|
||||
);
|
||||
|
||||
spin_lock(&lockref->lock);
|
||||
retval = 0;
|
||||
if (lockref->count > 1) {
|
||||
lockref->count--;
|
||||
retval = 1;
|
||||
}
|
||||
spin_unlock(&lockref->lock);
|
||||
return retval;
|
||||
}
|
||||
EXPORT_SYMBOL(lockref_put_not_zero);
|
||||
|
||||
/**
|
||||
* lockref_get_or_lock - Increments count unless the count is 0 or dead
|
||||
* @lockref: pointer to lockref structure
|
||||
|
|
Loading…
Reference in a new issue