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afs: Add some callback management tracepoints

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Add a couple of tracepoints to track callback management:

 (1) afs_cb_miss - Logs when we were unable to apply a callback, either due
     to the inode being discarded or due to a competing thread applying a
     callback first.

 (2) afs_cb_break - Logs when we attempted to clear the noted callback
     promise, either due to the server explicitly breaking the callback,
     the callback promise lapsing or a local event obsoleting it.

Signed-off-by: David Howells <dhowells@redhat.com>
This commit is contained in:
David Howells 2019-06-20 18:12:16 +01:00
parent fa59f52f5b
commit 051d25250b
5 changed files with 97 additions and 17 deletions
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16
fs/afs/callback.c
View File

@ -212,7 +212,7 @@ void afs_init_callback_state(struct afs_server *server)
/*
* actually break a callback
*/
void __afs_break_callback(struct afs_vnode *vnode)
void __afs_break_callback(struct afs_vnode *vnode, enum afs_cb_break_reason reason)
{
_enter("");
@ -223,13 +223,17 @@ void __afs_break_callback(struct afs_vnode *vnode)
if (vnode->lock_state == AFS_VNODE_LOCK_WAITING_FOR_CB)
afs_lock_may_be_available(vnode);
trace_afs_cb_break(&vnode->fid, vnode->cb_break, reason, true);
} else {
trace_afs_cb_break(&vnode->fid, vnode->cb_break, reason, false);
}
}
void afs_break_callback(struct afs_vnode *vnode)
void afs_break_callback(struct afs_vnode *vnode, enum afs_cb_break_reason reason)
{
write_seqlock(&vnode->cb_lock);
__afs_break_callback(vnode);
__afs_break_callback(vnode, reason);
write_sequnlock(&vnode->cb_lock);
}
@ -277,6 +281,8 @@ static void afs_break_one_callback(struct afs_server *server,
write_lock(&volume->cb_v_break_lock);
volume->cb_v_break++;
trace_afs_cb_break(fid, volume->cb_v_break,
afs_cb_break_for_volume_callback, false);
write_unlock(&volume->cb_v_break_lock);
} else {
data.volume = NULL;
@ -285,8 +291,10 @@ static void afs_break_one_callback(struct afs_server *server,
afs_iget5_test, &data);
if (inode) {
vnode = AFS_FS_I(inode);
afs_break_callback(vnode);
afs_break_callback(vnode, afs_cb_break_for_callback);
iput(inode);
} else {
trace_afs_cb_miss(fid, afs_cb_break_for_callback);
}
}
}

4
fs/afs/dir.c
View File

@ -1367,12 +1367,12 @@ static int afs_dir_remove_link(struct afs_vnode *dvnode, struct dentry *dentry,
drop_nlink(&vnode->vfs_inode);
if (vnode->vfs_inode.i_nlink == 0) {
set_bit(AFS_VNODE_DELETED, &vnode->flags);
__afs_break_callback(vnode);
__afs_break_callback(vnode, afs_cb_break_for_unlink);
}
write_sequnlock(&vnode->cb_lock);
ret = 0;
} else {
afs_break_callback(vnode);
afs_break_callback(vnode, afs_cb_break_for_unlink);
if (test_bit(AFS_VNODE_DELETED, &vnode->flags))
kdebug("AFS_VNODE_DELETED");

17
fs/afs/inode.c
View File

@ -283,7 +283,7 @@ void afs_vnode_commit_status(struct afs_fs_cursor *fc,
if (scb->status.abort_code == VNOVNODE) {
set_bit(AFS_VNODE_DELETED, &vnode->flags);
clear_nlink(&vnode->vfs_inode);
__afs_break_callback(vnode);
__afs_break_callback(vnode, afs_cb_break_for_deleted);
}
} else {
if (scb->have_status)
@ -594,8 +594,9 @@ bool afs_check_validity(struct afs_vnode *vnode)
struct afs_cb_interest *cbi;
struct afs_server *server;
struct afs_volume *volume = vnode->volume;
enum afs_cb_break_reason need_clear = afs_cb_break_no_break;
time64_t now = ktime_get_real_seconds();
bool valid, need_clear = false;
bool valid;
unsigned int cb_break, cb_s_break, cb_v_break;
int seq = 0;
@ -613,13 +614,13 @@ bool afs_check_validity(struct afs_vnode *vnode)
vnode->cb_v_break != cb_v_break) {
vnode->cb_s_break = cb_s_break;
vnode->cb_v_break = cb_v_break;
need_clear = true;
need_clear = afs_cb_break_for_vsbreak;
valid = false;
} else if (test_bit(AFS_VNODE_ZAP_DATA, &vnode->flags)) {
need_clear = true;
need_clear = afs_cb_break_for_zap;
valid = false;
} else if (vnode->cb_expires_at - 10 <= now) {
need_clear = true;
need_clear = afs_cb_break_for_lapsed;
valid = false;
} else {
valid = true;
@ -635,10 +636,12 @@ bool afs_check_validity(struct afs_vnode *vnode)
done_seqretry(&vnode->cb_lock, seq);
if (need_clear) {
if (need_clear != afs_cb_break_no_break) {
write_seqlock(&vnode->cb_lock);
if (cb_break == vnode->cb_break)
__afs_break_callback(vnode);
__afs_break_callback(vnode, need_clear);
else
trace_afs_cb_miss(&vnode->fid, need_clear);
write_sequnlock(&vnode->cb_lock);
valid = false;
}

8
fs/afs/internal.h
View File

@ -848,9 +848,9 @@ extern struct fscache_cookie_def afs_vnode_cache_index_def;
* callback.c
*/
extern void afs_init_callback_state(struct afs_server *);
extern void __afs_break_callback(struct afs_vnode *);
extern void afs_break_callback(struct afs_vnode *);
extern void afs_break_callbacks(struct afs_server *, size_t, struct afs_callback_break*);
extern void __afs_break_callback(struct afs_vnode *, enum afs_cb_break_reason);
extern void afs_break_callback(struct afs_vnode *, enum afs_cb_break_reason);
extern void afs_break_callbacks(struct afs_server *, size_t, struct afs_callback_break *);
extern int afs_register_server_cb_interest(struct afs_vnode *,
struct afs_server_list *, unsigned int);
@ -1438,7 +1438,7 @@ static inline void afs_check_for_remote_deletion(struct afs_fs_cursor *fc,
{
if (fc->ac.error == -ENOENT) {
set_bit(AFS_VNODE_DELETED, &vnode->flags);
afs_break_callback(vnode);
afs_break_callback(vnode, afs_cb_break_for_deleted);
}
}

69
include/trace/events/afs.h
View File

@ -195,6 +195,17 @@ enum afs_flock_operation {
afs_flock_op_wake,
};
enum afs_cb_break_reason {
afs_cb_break_no_break,
afs_cb_break_for_callback,
afs_cb_break_for_deleted,
afs_cb_break_for_lapsed,
afs_cb_break_for_unlink,
afs_cb_break_for_vsbreak,
afs_cb_break_for_volume_callback,
afs_cb_break_for_zap,
};
#endif /* end __AFS_DECLARE_TRACE_ENUMS_ONCE_ONLY */
/*
@ -374,6 +385,16 @@ enum afs_flock_operation {
EM(afs_flock_op_unlock, "UNLOCK ") \
E_(afs_flock_op_wake, "WAKE ")
#define afs_cb_break_reasons \
EM(afs_cb_break_no_break, "no-break") \
EM(afs_cb_break_for_callback, "break-cb") \
EM(afs_cb_break_for_deleted, "break-del") \
EM(afs_cb_break_for_lapsed, "break-lapsed") \
EM(afs_cb_break_for_unlink, "break-unlink") \
EM(afs_cb_break_for_vsbreak, "break-vs") \
EM(afs_cb_break_for_volume_callback, "break-v-cb") \
E_(afs_cb_break_for_zap, "break-zap")
/*
* Export enum symbols via userspace.
*/
@ -392,6 +413,7 @@ afs_io_errors;
afs_file_errors;
afs_flock_types;
afs_flock_operations;
afs_cb_break_reasons;
/*
* Now redefine the EM() and E_() macros to map the enums to the strings that
@ -1171,6 +1193,53 @@ TRACE_EVENT(afs_get_tree,
__entry->cell, __entry->volume, __entry->vid)
);
TRACE_EVENT(afs_cb_break,
TP_PROTO(struct afs_fid *fid, unsigned int cb_break,
enum afs_cb_break_reason reason, bool skipped),
TP_ARGS(fid, cb_break, reason, skipped),
TP_STRUCT__entry(
__field_struct(struct afs_fid, fid )
__field(unsigned int, cb_break )
__field(enum afs_cb_break_reason, reason )
__field(bool, skipped )
),
TP_fast_assign(
__entry->fid = *fid;
__entry->cb_break = cb_break;
__entry->reason = reason;
__entry->skipped = skipped;
),
TP_printk("%llx:%llx:%x b=%x s=%u %s",
__entry->fid.vid, __entry->fid.vnode, __entry->fid.unique,
__entry->cb_break,
__entry->skipped,
__print_symbolic(__entry->reason, afs_cb_break_reasons))
);
TRACE_EVENT(afs_cb_miss,
TP_PROTO(struct afs_fid *fid, enum afs_cb_break_reason reason),
TP_ARGS(fid, reason),
TP_STRUCT__entry(
__field_struct(struct afs_fid, fid )
__field(enum afs_cb_break_reason, reason )
),
TP_fast_assign(
__entry->fid = *fid;
__entry->reason = reason;
),
TP_printk(" %llx:%llx:%x %s",
__entry->fid.vid, __entry->fid.vnode, __entry->fid.unique,
__print_symbolic(__entry->reason, afs_cb_break_reasons))
);
#endif /* _TRACE_AFS_H */
/* This part must be outside protection */