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gfs2: Get rid of sd_reserving_log 

This counter and the associated wait queue are only used so that
gfs2_make_fs_ro can efficiently wait for all pending log space
allocations to fail after setting the filesystem to read-only.  This
comes at the cost of waking up that wait queue very frequently.

Instead, when gfs2_log_reserve fails because the filesystem has become
read-only, Wake up sd_log_waitq.  In gfs2_make_fs_ro, set the file
system read-only and then wait until all the log space has been
released.  Give up and report the problem after a while.  With that,
sd_reserving_log and sd_reserving_log_wait can be removed.

Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
This commit is contained in:
Andreas Gruenbacher 2020-12-13 09:21:34 +01:00
parent c968f5788b
commit f3708fb59f
6 changed files with 19 additions and 18 deletions
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3
fs/gfs2/incore.h
View File

@ -849,9 +849,6 @@ struct gfs2_sbd {
int sd_log_error; /* First log error */
wait_queue_head_t sd_withdraw_wait;
atomic_t sd_reserving_log;
wait_queue_head_t sd_reserving_log_wait;
unsigned int sd_log_flush_head;
spinlock_t sd_ail_lock;

17
fs/gfs2/log.c
View File

@ -397,6 +397,15 @@ static void ail2_empty(struct gfs2_sbd *sdp, unsigned int new_tail)
spin_unlock(&sdp->sd_ail_lock);
}
/**
* gfs2_log_is_empty - Check if the log is empty
* @sdp: The GFS2 superblock
*/
bool gfs2_log_is_empty(struct gfs2_sbd *sdp) {
return atomic_read(&sdp->sd_log_blks_free) == sdp->sd_jdesc->jd_blocks;
}
/**
* gfs2_log_release - Release a given number of log blocks
* @sdp: The GFS2 superblock
@ -461,13 +470,9 @@ retry:
} while(free_blocks <= wanted);
finish_wait(&sdp->sd_log_waitq, &wait);
}
atomic_inc(&sdp->sd_reserving_log);
if (atomic_cmpxchg(&sdp->sd_log_blks_free, free_blocks,
free_blocks - blks) != free_blocks) {
if (atomic_dec_and_test(&sdp->sd_reserving_log))
wake_up(&sdp->sd_reserving_log_wait);
free_blocks - blks) != free_blocks)
goto retry;
}
atomic_sub(blks, &sdp->sd_log_blks_needed);
trace_gfs2_log_blocks(sdp, -blks);
@ -483,8 +488,6 @@ retry:
gfs2_log_release(sdp, blks);
ret = -EROFS;
}
if (atomic_dec_and_test(&sdp->sd_reserving_log))
wake_up(&sdp->sd_reserving_log_wait);
return ret;
}

1
fs/gfs2/log.h
View File

@ -64,6 +64,7 @@ static inline void gfs2_ordered_add_inode(struct gfs2_inode *ip)
extern void gfs2_ordered_del_inode(struct gfs2_inode *ip);
extern unsigned int gfs2_struct2blk(struct gfs2_sbd *sdp, unsigned int nstruct);
extern void gfs2_remove_from_ail(struct gfs2_bufdata *bd);
extern bool gfs2_log_is_empty(struct gfs2_sbd *sdp);
extern void gfs2_log_release(struct gfs2_sbd *sdp, unsigned int blks);
extern int gfs2_log_reserve(struct gfs2_sbd *sdp, unsigned int blks);
extern void gfs2_write_log_header(struct gfs2_sbd *sdp, struct gfs2_jdesc *jd,

2
fs/gfs2/ops_fstype.c
View File

@ -136,8 +136,6 @@ static struct gfs2_sbd *init_sbd(struct super_block *sb)
init_rwsem(&sdp->sd_log_flush_lock);
atomic_set(&sdp->sd_log_in_flight, 0);
atomic_set(&sdp->sd_reserving_log, 0);
init_waitqueue_head(&sdp->sd_reserving_log_wait);
init_waitqueue_head(&sdp->sd_log_flush_wait);
atomic_set(&sdp->sd_freeze_state, SFS_UNFROZEN);
mutex_init(&sdp->sd_freeze_mutex);

12
fs/gfs2/super.c
View File

@ -645,13 +645,13 @@ int gfs2_make_fs_ro(struct gfs2_sbd *sdp)
gfs2_log_flush(sdp, NULL, GFS2_LOG_HEAD_FLUSH_SHUTDOWN |
GFS2_LFC_MAKE_FS_RO);
wait_event(sdp->sd_reserving_log_wait,
atomic_read(&sdp->sd_reserving_log) == 0);
gfs2_assert_warn(sdp, atomic_read(&sdp->sd_log_blks_free) ==
sdp->sd_jdesc->jd_blocks);
wait_event_timeout(sdp->sd_log_waitq,
gfs2_log_is_empty(sdp),
HZ * 5);
gfs2_assert_warn(sdp, gfs2_log_is_empty(sdp));
} else {
wait_event_timeout(sdp->sd_reserving_log_wait,
atomic_read(&sdp->sd_reserving_log) == 0,
wait_event_timeout(sdp->sd_log_waitq,
gfs2_log_is_empty(sdp),
HZ * 5);
}
if (gfs2_holder_initialized(&freeze_gh))

2
fs/gfs2/trans.c
View File

@ -71,6 +71,8 @@ int __gfs2_trans_begin(struct gfs2_trans *tr, struct gfs2_sbd *sdp,
error = gfs2_log_reserve(sdp, tr->tr_reserved);
if (error) {
sb_end_intwrite(sdp->sd_vfs);
if (error == -EROFS)
wake_up(&sdp->sd_log_waitq);
return error;
}