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Clarify locking of cifs file and tcon structures and make more granular

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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>
This commit is contained in:
Steve French 2016-09-22 18:58:16 -05:00
parent d171356ff1
commit 3afca265b5
7 changed files with 75 additions and 63 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
fs/cifs/cifsfs.c
View File

@ -1262,7 +1262,6 @@ init_cifs(void)
GlobalTotalActiveXid = 0;
GlobalMaxActiveXid = 0;
spin_lock_init(&cifs_tcp_ses_lock);
spin_lock_init(&cifs_file_list_lock);
spin_lock_init(&GlobalMid_Lock);
get_random_bytes(&cifs_lock_secret, sizeof(cifs_lock_secret));

30
fs/cifs/cifsglob.h
View File

@ -833,6 +833,7 @@ struct cifs_tcon {
struct list_head tcon_list;
int tc_count;
struct list_head openFileList;
spinlock_t open_file_lock; /* protects list above */
struct cifs_ses *ses; /* pointer to session associated with */
char treeName[MAX_TREE_SIZE + 1]; /* UNC name of resource in ASCII */
char *nativeFileSystem;
@ -889,7 +890,7 @@ struct cifs_tcon {
#endif /* CONFIG_CIFS_STATS2 */
__u64 bytes_read;
__u64 bytes_written;
spinlock_t stat_lock;
spinlock_t stat_lock; /* protects the two fields above */
#endif /* CONFIG_CIFS_STATS */
FILE_SYSTEM_DEVICE_INFO fsDevInfo;
FILE_SYSTEM_ATTRIBUTE_INFO fsAttrInfo; /* ok if fs name truncated */
@ -1040,8 +1041,10 @@ struct cifs_fid_locks {
};
struct cifsFileInfo {
/* following two lists are protected by tcon->open_file_lock */
struct list_head tlist; /* pointer to next fid owned by tcon */
struct list_head flist; /* next fid (file instance) for this inode */
/* lock list below protected by cifsi->lock_sem */
struct cifs_fid_locks *llist; /* brlocks held by this fid */
kuid_t uid; /* allows finding which FileInfo structure */
__u32 pid; /* process id who opened file */
@ -1049,11 +1052,12 @@ struct cifsFileInfo {
/* BB add lock scope info here if needed */ ;
/* lock scope id (0 if none) */
struct dentry *dentry;
unsigned int f_flags;
struct tcon_link *tlink;
unsigned int f_flags;
bool invalidHandle:1; /* file closed via session abend */
bool oplock_break_cancelled:1;
int count; /* refcount protected by cifs_file_list_lock */
int count;
spinlock_t file_info_lock; /* protects four flag/count fields above */
struct mutex fh_mutex; /* prevents reopen race after dead ses*/
struct cifs_search_info srch_inf;
struct work_struct oplock_break; /* work for oplock breaks */
@ -1120,7 +1124,7 @@ struct cifs_writedata {
/*
* Take a reference on the file private data. Must be called with
* cifs_file_list_lock held.
* cfile->file_info_lock held.
*/
static inline void
cifsFileInfo_get_locked(struct cifsFileInfo *cifs_file)
@ -1514,8 +1518,10 @@ require use of the stronger protocol */
* GlobalMid_Lock protects:
* list operations on pending_mid_q and oplockQ
* updates to XID counters, multiplex id and SMB sequence numbers
* cifs_file_list_lock protects:
* list operations on tcp and SMB session lists and tCon lists
* tcp_ses_lock protects:
* list operations on tcp and SMB session lists
* tcon->open_file_lock protects the list of open files hanging off the tcon
* cfile->file_info_lock protects counters and fields in cifs file struct
* f_owner.lock protects certain per file struct operations
* mapping->page_lock protects certain per page operations
*
@ -1547,18 +1553,12 @@ GLOBAL_EXTERN struct list_head cifs_tcp_ses_list;
* tcp session, and the list of tcon's per smb session. It also protects
* the reference counters for the server, smb session, and tcon. Finally,
* changes to the tcon->tidStatus should be done while holding this lock.
* generally the locks should be taken in order tcp_ses_lock before
* tcon->open_file_lock and that before file->file_info_lock since the
* structure order is cifs_socket-->cifs_ses-->cifs_tcon-->cifs_file
*/
GLOBAL_EXTERN spinlock_t cifs_tcp_ses_lock;
/*
* This lock protects the cifs_file->llist and cifs_file->flist
* list operations, and updates to some flags (cifs_file->invalidHandle)
* It will be moved to either use the tcon->stat_lock or equivalent later.
* If cifs_tcp_ses_lock and the lock below are both needed to be held, then
* the cifs_tcp_ses_lock must be grabbed first and released last.
*/
GLOBAL_EXTERN spinlock_t cifs_file_list_lock;
#ifdef CONFIG_CIFS_DNOTIFY_EXPERIMENTAL /* unused temporarily */
/* Outstanding dir notify requests */
GLOBAL_EXTERN struct list_head GlobalDnotifyReqList;

4
fs/cifs/cifssmb.c
View File

@ -98,13 +98,13 @@ cifs_mark_open_files_invalid(struct cifs_tcon *tcon)
struct list_head *tmp1;
/* list all files open on tree connection and mark them invalid */
spin_lock(&cifs_file_list_lock);
spin_lock(&tcon->open_file_lock);
list_for_each_safe(tmp, tmp1, &tcon->openFileList) {
open_file = list_entry(tmp, struct cifsFileInfo, tlist);
open_file->invalidHandle = true;
open_file->oplock_break_cancelled = true;
}
spin_unlock(&cifs_file_list_lock);
spin_unlock(&tcon->open_file_lock);
/*
* BB Add call to invalidate_inodes(sb) for all superblocks mounted
* to this tcon.

66
fs/cifs/file.c
View File

@ -305,6 +305,7 @@ cifs_new_fileinfo(struct cifs_fid *fid, struct file *file,
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 @@ cifs_new_fileinfo(struct cifs_fid *fid, struct file *file,
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 @@ cifs_new_fileinfo(struct cifs_fid *fid, struct file *file,
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 @@ cifs_new_fileinfo(struct cifs_fid *fid, struct file *file,
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 @@ void cifsFileInfo_put(struct cifsFileInfo *cifs_file)
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 @@ void cifsFileInfo_put(struct cifsFileInfo *cifs_file)
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 @@ int cifs_closedir(struct inode *inode, struct file *file)
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 @@ int cifs_closedir(struct inode *inode, struct file *file)
/* 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 *find_readable_file(struct cifsInodeInfo *cifs_inode,
{
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 @@ struct cifsFileInfo *find_readable_file(struct cifsInodeInfo *cifs_inode,
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 @@ struct cifsFileInfo *find_readable_file(struct cifsInodeInfo *cifs_inode,
} 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 *find_writable_file(struct cifsInodeInfo *cifs_inode,
{
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 @@ struct cifsFileInfo *find_writable_file(struct cifsInodeInfo *cifs_inode,
}
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 @@ refind_writable:
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 @@ refind_writable:
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 cifs_readpage(struct file *file, struct page *page)
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;
}

15
fs/cifs/misc.c
View File

@ -120,6 +120,7 @@ tconInfoAlloc(void)
++ret_buf->tc_count;
INIT_LIST_HEAD(&ret_buf->openFileList);
INIT_LIST_HEAD(&ret_buf->tcon_list);
spin_lock_init(&ret_buf->open_file_lock);
#ifdef CONFIG_CIFS_STATS
spin_lock_init(&ret_buf->stat_lock);
#endif
@ -465,7 +466,7 @@ is_valid_oplock_break(char *buffer, struct TCP_Server_Info *srv)
continue;
cifs_stats_inc(&tcon->stats.cifs_stats.num_oplock_brks);
spin_lock(&cifs_file_list_lock);
spin_lock(&tcon->open_file_lock);
list_for_each(tmp2, &tcon->openFileList) {
netfile = list_entry(tmp2, struct cifsFileInfo,
tlist);
@ -495,11 +496,11 @@ is_valid_oplock_break(char *buffer, struct TCP_Server_Info *srv)
&netfile->oplock_break);
netfile->oplock_break_cancelled = false;
spin_unlock(&cifs_file_list_lock);
spin_unlock(&tcon->open_file_lock);
spin_unlock(&cifs_tcp_ses_lock);
return true;
}
spin_unlock(&cifs_file_list_lock);
spin_unlock(&tcon->open_file_lock);
spin_unlock(&cifs_tcp_ses_lock);
cifs_dbg(FYI, "No matching file for oplock break\n");
return true;
@ -613,9 +614,9 @@ backup_cred(struct cifs_sb_info *cifs_sb)
void
cifs_del_pending_open(struct cifs_pending_open *open)
{
spin_lock(&cifs_file_list_lock);
spin_lock(&tlink_tcon(open->tlink)->open_file_lock);
list_del(&open->olist);
spin_unlock(&cifs_file_list_lock);
spin_unlock(&tlink_tcon(open->tlink)->open_file_lock);
}
void
@ -635,7 +636,7 @@ void
cifs_add_pending_open(struct cifs_fid *fid, struct tcon_link *tlink,
struct cifs_pending_open *open)
{
spin_lock(&cifs_file_list_lock);
spin_lock(&tlink_tcon(tlink)->open_file_lock);
cifs_add_pending_open_locked(fid, tlink, open);
spin_unlock(&cifs_file_list_lock);
spin_unlock(&tlink_tcon(open->tlink)->open_file_lock);
}

6
fs/cifs/readdir.c
View File

@ -597,14 +597,14 @@ find_cifs_entry(const unsigned int xid, struct cifs_tcon *tcon, loff_t pos,
is_dir_changed(file)) || (index_to_find < first_entry_in_buffer)) {
/* close and restart search */
cifs_dbg(FYI, "search backing up - close and restart search\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)
server->ops->close_dir(xid, tcon, &cfile->fid);
} else
spin_unlock(&cifs_file_list_lock);
spin_unlock(&cfile->file_info_lock);
if (cfile->srch_inf.ntwrk_buf_start) {
cifs_dbg(FYI, "freeing SMB ff cache buf on search rewind\n");
if (cfile->srch_inf.smallBuf)

16
fs/cifs/smb2misc.c
View File

@ -549,19 +549,19 @@ smb2_is_valid_lease_break(char *buffer)
list_for_each(tmp1, &server->smb_ses_list) {
ses = list_entry(tmp1, struct cifs_ses, smb_ses_list);
spin_lock(&cifs_file_list_lock);
list_for_each(tmp2, &ses->tcon_list) {
tcon = list_entry(tmp2, struct cifs_tcon,
tcon_list);
spin_lock(&tcon->open_file_lock);
cifs_stats_inc(
&tcon->stats.cifs_stats.num_oplock_brks);
if (smb2_tcon_has_lease(tcon, rsp, lw)) {
spin_unlock(&cifs_file_list_lock);
spin_unlock(&tcon->open_file_lock);
spin_unlock(&cifs_tcp_ses_lock);
return true;
}
spin_unlock(&tcon->open_file_lock);
}
spin_unlock(&cifs_file_list_lock);
}
}
spin_unlock(&cifs_tcp_ses_lock);
@ -603,7 +603,7 @@ smb2_is_valid_oplock_break(char *buffer, struct TCP_Server_Info *server)
tcon = list_entry(tmp1, struct cifs_tcon, tcon_list);
cifs_stats_inc(&tcon->stats.cifs_stats.num_oplock_brks);
spin_lock(&cifs_file_list_lock);
spin_lock(&tcon->open_file_lock);
list_for_each(tmp2, &tcon->openFileList) {
cfile = list_entry(tmp2, struct cifsFileInfo,
tlist);
@ -615,7 +615,7 @@ smb2_is_valid_oplock_break(char *buffer, struct TCP_Server_Info *server)
cifs_dbg(FYI, "file id match, oplock break\n");
cinode = CIFS_I(d_inode(cfile->dentry));
spin_lock(&cfile->file_info_lock);
if (!CIFS_CACHE_WRITE(cinode) &&
rsp->OplockLevel == SMB2_OPLOCK_LEVEL_NONE)
cfile->oplock_break_cancelled = true;
@ -637,14 +637,14 @@ smb2_is_valid_oplock_break(char *buffer, struct TCP_Server_Info *server)
clear_bit(
CIFS_INODE_DOWNGRADE_OPLOCK_TO_L2,
&cinode->flags);
spin_unlock(&cfile->file_info_lock);
queue_work(cifsiod_wq, &cfile->oplock_break);
spin_unlock(&cifs_file_list_lock);
spin_unlock(&tcon->open_file_lock);
spin_unlock(&cifs_tcp_ses_lock);
return true;
}
spin_unlock(&cifs_file_list_lock);
spin_unlock(&tcon->open_file_lock);
spin_unlock(&cifs_tcp_ses_lock);
cifs_dbg(FYI, "No matching file for oplock break\n");
return true;