Clarify locking of cifs file and tcon structures and make more granular
Remove the global file_list_lock to simplify cifs/smb3 locking and
have spinlocks that more closely match the information they are
protecting.
Add new tcon->open_file_lock and file->file_info_lock spinlocks.
Locks continue to follow a heirachy,
cifs_socket --> cifs_ses --> cifs_tcon --> cifs_file
where global tcp_ses_lock still protects socket and cifs_ses, while the
the newer locks protect the lower level structure's information
(tcon and cifs_file respectively).
CC: Stable <stable@vger.kernel.org>
Signed-off-by: Steve French <steve.french@primarydata.com>
Signed-off-by: Pavel Shilovsky <pshilov@microsoft.com>
Reviewed-by: Aurelien Aptel <aaptel@suse.com>
Reviewed-by: Germano Percossi <germano.percossi@citrix.com>
diff --git a/fs/cifs/file.c b/fs/cifs/file.c
index a95fe8b..ee5ceae 100644
--- a/fs/cifs/file.c
+++ b/fs/cifs/file.c
@@ -305,6 +305,7 @@
cfile->tlink = cifs_get_tlink(tlink);
INIT_WORK(&cfile->oplock_break, cifs_oplock_break);
mutex_init(&cfile->fh_mutex);
+ spin_lock_init(&cfile->file_info_lock);
cifs_sb_active(inode->i_sb);
@@ -317,7 +318,7 @@
oplock = 0;
}
- spin_lock(&cifs_file_list_lock);
+ spin_lock(&tcon->open_file_lock);
if (fid->pending_open->oplock != CIFS_OPLOCK_NO_CHANGE && oplock)
oplock = fid->pending_open->oplock;
list_del(&fid->pending_open->olist);
@@ -326,12 +327,13 @@
server->ops->set_fid(cfile, fid, oplock);
list_add(&cfile->tlist, &tcon->openFileList);
+
/* if readable file instance put first in list*/
if (file->f_mode & FMODE_READ)
list_add(&cfile->flist, &cinode->openFileList);
else
list_add_tail(&cfile->flist, &cinode->openFileList);
- spin_unlock(&cifs_file_list_lock);
+ spin_unlock(&tcon->open_file_lock);
if (fid->purge_cache)
cifs_zap_mapping(inode);
@@ -343,16 +345,16 @@
struct cifsFileInfo *
cifsFileInfo_get(struct cifsFileInfo *cifs_file)
{
- spin_lock(&cifs_file_list_lock);
+ spin_lock(&cifs_file->file_info_lock);
cifsFileInfo_get_locked(cifs_file);
- spin_unlock(&cifs_file_list_lock);
+ spin_unlock(&cifs_file->file_info_lock);
return cifs_file;
}
/*
* Release a reference on the file private data. This may involve closing
* the filehandle out on the server. Must be called without holding
- * cifs_file_list_lock.
+ * tcon->open_file_lock and cifs_file->file_info_lock.
*/
void cifsFileInfo_put(struct cifsFileInfo *cifs_file)
{
@@ -367,11 +369,15 @@
struct cifs_pending_open open;
bool oplock_break_cancelled;
- spin_lock(&cifs_file_list_lock);
+ spin_lock(&tcon->open_file_lock);
+
+ spin_lock(&cifs_file->file_info_lock);
if (--cifs_file->count > 0) {
- spin_unlock(&cifs_file_list_lock);
+ spin_unlock(&cifs_file->file_info_lock);
+ spin_unlock(&tcon->open_file_lock);
return;
}
+ spin_unlock(&cifs_file->file_info_lock);
if (server->ops->get_lease_key)
server->ops->get_lease_key(inode, &fid);
@@ -395,7 +401,8 @@
set_bit(CIFS_INO_INVALID_MAPPING, &cifsi->flags);
cifs_set_oplock_level(cifsi, 0);
}
- spin_unlock(&cifs_file_list_lock);
+
+ spin_unlock(&tcon->open_file_lock);
oplock_break_cancelled = cancel_work_sync(&cifs_file->oplock_break);
@@ -772,10 +779,10 @@
server = tcon->ses->server;
cifs_dbg(FYI, "Freeing private data in close dir\n");
- spin_lock(&cifs_file_list_lock);
+ spin_lock(&cfile->file_info_lock);
if (server->ops->dir_needs_close(cfile)) {
cfile->invalidHandle = true;
- spin_unlock(&cifs_file_list_lock);
+ spin_unlock(&cfile->file_info_lock);
if (server->ops->close_dir)
rc = server->ops->close_dir(xid, tcon, &cfile->fid);
else
@@ -784,7 +791,7 @@
/* not much we can do if it fails anyway, ignore rc */
rc = 0;
} else
- spin_unlock(&cifs_file_list_lock);
+ spin_unlock(&cfile->file_info_lock);
buf = cfile->srch_inf.ntwrk_buf_start;
if (buf) {
@@ -1728,12 +1735,13 @@
{
struct cifsFileInfo *open_file = NULL;
struct cifs_sb_info *cifs_sb = CIFS_SB(cifs_inode->vfs_inode.i_sb);
+ struct cifs_tcon *tcon = cifs_sb_master_tcon(cifs_sb);
/* only filter by fsuid on multiuser mounts */
if (!(cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MULTIUSER))
fsuid_only = false;
- spin_lock(&cifs_file_list_lock);
+ spin_lock(&tcon->open_file_lock);
/* we could simply get the first_list_entry since write-only entries
are always at the end of the list but since the first entry might
have a close pending, we go through the whole list */
@@ -1744,8 +1752,8 @@
if (!open_file->invalidHandle) {
/* found a good file */
/* lock it so it will not be closed on us */
- cifsFileInfo_get_locked(open_file);
- spin_unlock(&cifs_file_list_lock);
+ cifsFileInfo_get(open_file);
+ spin_unlock(&tcon->open_file_lock);
return open_file;
} /* else might as well continue, and look for
another, or simply have the caller reopen it
@@ -1753,7 +1761,7 @@
} else /* write only file */
break; /* write only files are last so must be done */
}
- spin_unlock(&cifs_file_list_lock);
+ spin_unlock(&tcon->open_file_lock);
return NULL;
}
@@ -1762,6 +1770,7 @@
{
struct cifsFileInfo *open_file, *inv_file = NULL;
struct cifs_sb_info *cifs_sb;
+ struct cifs_tcon *tcon;
bool any_available = false;
int rc;
unsigned int refind = 0;
@@ -1777,15 +1786,16 @@
}
cifs_sb = CIFS_SB(cifs_inode->vfs_inode.i_sb);
+ tcon = cifs_sb_master_tcon(cifs_sb);
/* only filter by fsuid on multiuser mounts */
if (!(cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MULTIUSER))
fsuid_only = false;
- spin_lock(&cifs_file_list_lock);
+ spin_lock(&tcon->open_file_lock);
refind_writable:
if (refind > MAX_REOPEN_ATT) {
- spin_unlock(&cifs_file_list_lock);
+ spin_unlock(&tcon->open_file_lock);
return NULL;
}
list_for_each_entry(open_file, &cifs_inode->openFileList, flist) {
@@ -1796,8 +1806,8 @@
if (OPEN_FMODE(open_file->f_flags) & FMODE_WRITE) {
if (!open_file->invalidHandle) {
/* found a good writable file */
- cifsFileInfo_get_locked(open_file);
- spin_unlock(&cifs_file_list_lock);
+ cifsFileInfo_get(open_file);
+ spin_unlock(&tcon->open_file_lock);
return open_file;
} else {
if (!inv_file)
@@ -1813,24 +1823,24 @@
if (inv_file) {
any_available = false;
- cifsFileInfo_get_locked(inv_file);
+ cifsFileInfo_get(inv_file);
}
- spin_unlock(&cifs_file_list_lock);
+ spin_unlock(&tcon->open_file_lock);
if (inv_file) {
rc = cifs_reopen_file(inv_file, false);
if (!rc)
return inv_file;
else {
- spin_lock(&cifs_file_list_lock);
+ spin_lock(&tcon->open_file_lock);
list_move_tail(&inv_file->flist,
&cifs_inode->openFileList);
- spin_unlock(&cifs_file_list_lock);
+ spin_unlock(&tcon->open_file_lock);
cifsFileInfo_put(inv_file);
- spin_lock(&cifs_file_list_lock);
++refind;
inv_file = NULL;
+ spin_lock(&tcon->open_file_lock);
goto refind_writable;
}
}
@@ -3612,15 +3622,17 @@
static int is_inode_writable(struct cifsInodeInfo *cifs_inode)
{
struct cifsFileInfo *open_file;
+ struct cifs_tcon *tcon =
+ cifs_sb_master_tcon(CIFS_SB(cifs_inode->vfs_inode.i_sb));
- spin_lock(&cifs_file_list_lock);
+ spin_lock(&tcon->open_file_lock);
list_for_each_entry(open_file, &cifs_inode->openFileList, flist) {
if (OPEN_FMODE(open_file->f_flags) & FMODE_WRITE) {
- spin_unlock(&cifs_file_list_lock);
+ spin_unlock(&tcon->open_file_lock);
return 1;
}
}
- spin_unlock(&cifs_file_list_lock);
+ spin_unlock(&tcon->open_file_lock);
return 0;
}