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| author | David Howells <dhowells@redhat.com> | 2019-05-13 16:14:32 +0100 |
|---|---|---|
| committer | David Howells <dhowells@redhat.com> | 2019-05-16 22:23:21 +0100 |
| commit | f642404a0436a50912c218009ccc7856d48d784c (patch) | |
| tree | ddf39d1741f07866333581e66f1abc0e6709d453 /fs/afs/rotate.c | |
| parent | c925bd0ac4741badb567f594c41c8cba5e9e9732 (diff) | |
| download | linux-f642404a0436a50912c218009ccc7856d48d784c.tar.bz2 | |
afs: Make vnode->cb_interest RCU safe
Use RCU-based freeing for afs_cb_interest struct objects and use RCU on
vnode->cb_interest. Use that change to allow afs_check_validity() to use
read_seqbegin_or_lock() instead of read_seqlock_excl().
This also requires the caller of afs_check_validity() to hold the RCU read
lock across the call.
Signed-off-by: David Howells <dhowells@redhat.com>
Diffstat (limited to 'fs/afs/rotate.c')
| -rw-r--r-- | fs/afs/rotate.c | 18 |
1 files changed, 12 insertions, 6 deletions
diff --git a/fs/afs/rotate.c b/fs/afs/rotate.c index 52f3a9910f0d..b00c739e0e63 100644 --- a/fs/afs/rotate.c +++ b/fs/afs/rotate.c @@ -66,7 +66,8 @@ static bool afs_start_fs_iteration(struct afs_fs_cursor *fc, fc->untried = (1UL << fc->server_list->nr_servers) - 1; fc->index = READ_ONCE(fc->server_list->preferred); - cbi = vnode->cb_interest; + cbi = rcu_dereference_protected(vnode->cb_interest, + lockdep_is_held(&vnode->io_lock)); if (cbi) { /* See if the vnode's preferred record is still available */ for (i = 0; i < fc->server_list->nr_servers; i++) { @@ -87,8 +88,8 @@ static bool afs_start_fs_iteration(struct afs_fs_cursor *fc, /* Note that the callback promise is effectively broken */ write_seqlock(&vnode->cb_lock); - ASSERTCMP(cbi, ==, vnode->cb_interest); - vnode->cb_interest = NULL; + ASSERTCMP(cbi, ==, rcu_access_pointer(vnode->cb_interest)); + rcu_assign_pointer(vnode->cb_interest, NULL); if (test_and_clear_bit(AFS_VNODE_CB_PROMISED, &vnode->flags)) vnode->cb_break++; write_sequnlock(&vnode->cb_lock); @@ -417,7 +418,9 @@ selected_server: if (error < 0) goto failed_set_error; - fc->cbi = afs_get_cb_interest(vnode->cb_interest); + fc->cbi = afs_get_cb_interest( + rcu_dereference_protected(vnode->cb_interest, + lockdep_is_held(&vnode->io_lock))); read_lock(&server->fs_lock); alist = rcu_dereference_protected(server->addresses, @@ -487,12 +490,15 @@ failed: bool afs_select_current_fileserver(struct afs_fs_cursor *fc) { struct afs_vnode *vnode = fc->vnode; - struct afs_cb_interest *cbi = vnode->cb_interest; + struct afs_cb_interest *cbi; struct afs_addr_list *alist; int error = fc->ac.error; _enter(""); + cbi = rcu_dereference_protected(vnode->cb_interest, + lockdep_is_held(&vnode->io_lock)); + switch (error) { case SHRT_MAX: if (!cbi) { @@ -501,7 +507,7 @@ bool afs_select_current_fileserver(struct afs_fs_cursor *fc) return false; } - fc->cbi = afs_get_cb_interest(vnode->cb_interest); + fc->cbi = afs_get_cb_interest(cbi); read_lock(&cbi->server->fs_lock); alist = rcu_dereference_protected(cbi->server->addresses, |