Currently CIFS code accept read/write ops on mandatory locked area
when two processes use the same file descriptor - it's wrong.
Fix this by serializing io and brlock operations on the inode.
Signed-off-by: Pavel Shilovsky <pshilovsky@xxxxxxxxxxx>
---
fs/cifs/cifsproto.h | 4 ++
fs/cifs/file.c | 123 +++++++++++++++++++++++++++++++++++++++++----------
2 files changed, 103 insertions(+), 24 deletions(-)
diff --git a/fs/cifs/cifsproto.h b/fs/cifs/cifsproto.h
index 15e38dc..c758ee7 100644
--- a/fs/cifs/cifsproto.h
+++ b/fs/cifs/cifsproto.h
@@ -180,6 +180,10 @@ extern struct smb_vol *cifs_get_volume_info(char *mount_data,
extern int cifs_mount(struct cifs_sb_info *, struct smb_vol *);
extern void cifs_umount(struct cifs_sb_info *);
extern void cifs_mark_open_files_invalid(struct cifs_tcon *tcon);
+extern bool cifs_find_lock_conflict(struct cifsFileInfo *cfile, __u64 offset,
+ __u64 length, __u8 type,
+ struct cifsLockInfo **conf_lock,
+ bool rw_check);
#if IS_ENABLED(CONFIG_CIFS_DFS_UPCALL)
extern void cifs_dfs_release_automount_timer(void);
diff --git a/fs/cifs/file.c b/fs/cifs/file.c
index daeb817..ecc0d5d 100644
--- a/fs/cifs/file.c
+++ b/fs/cifs/file.c
@@ -704,10 +704,10 @@ cifs_del_lock_waiters(struct cifsLockInfo *lock)
}
}
-static bool
+extern bool
cifs_find_fid_lock_conflict(struct cifs_fid_locks *fdlocks, __u64 offset,
__u64 length, __u8 type, struct cifsFileInfo *cfile,
- struct cifsLockInfo **conf_lock)
+ struct cifsLockInfo **conf_lock, bool rw_check)
{
struct cifsLockInfo *li;
struct cifsFileInfo *cur_cfile = fdlocks->cfile;
@@ -717,19 +717,24 @@ cifs_find_fid_lock_conflict(struct cifs_fid_locks *fdlocks, __u64 offset,
if (offset + length <= li->offset ||
offset >= li->offset + li->length)
continue;
+ if (rw_check && server->ops->compare_fids(cfile, cur_cfile) &&
+ current->tgid == li->pid)
+ continue;
if ((type & server->vals->shared_lock_type) &&
((server->ops->compare_fids(cfile, cur_cfile) &&
current->tgid == li->pid) || type == li->type))
continue;
- *conf_lock = li;
+ if (conf_lock)
+ *conf_lock = li;
return true;
}
return false;
}
-static bool
+bool
cifs_find_lock_conflict(struct cifsFileInfo *cfile, __u64 offset, __u64 length,
- __u8 type, struct cifsLockInfo **conf_lock)
+ __u8 type, struct cifsLockInfo **conf_lock,
+ bool rw_check)
{
bool rc = false;
struct cifs_fid_locks *cur;
@@ -737,7 +742,7 @@ cifs_find_lock_conflict(struct cifsFileInfo *cfile, __u64 offset, __u64 length,
list_for_each_entry(cur, &cinode->llist, llist) {
rc = cifs_find_fid_lock_conflict(cur, offset, length, type,
- cfile, conf_lock);
+ cfile, conf_lock, rw_check);
if (rc)
break;
}
@@ -765,7 +770,7 @@ cifs_lock_test(struct cifsFileInfo *cfile, __u64 offset, __u64 length,
down_read(&cinode->lock_sem);
exist = cifs_find_lock_conflict(cfile, offset, length, type,
- &conf_lock);
+ &conf_lock, false);
if (exist) {
flock->fl_start = conf_lock->offset;
flock->fl_end = conf_lock->offset + conf_lock->length - 1;
@@ -812,7 +817,7 @@ try_again:
down_write(&cinode->lock_sem);
exist = cifs_find_lock_conflict(cfile, lock->offset, lock->length,
- lock->type, &conf_lock);
+ lock->type, &conf_lock, false);
if (!exist && cinode->can_cache_brlcks) {
list_add_tail(&lock->llist, &cfile->llist->locks);
up_write(&cinode->lock_sem);
@@ -2394,15 +2399,58 @@ ssize_t cifs_user_writev(struct kiocb *iocb, const struct iovec *iov,
return written;
}
-ssize_t cifs_strict_writev(struct kiocb *iocb, const struct iovec *iov,
- unsigned long nr_segs, loff_t pos)
+static ssize_t
+cifs_writev(struct kiocb *iocb, const struct iovec *iov,
+ unsigned long nr_segs, loff_t pos)
{
- struct inode *inode;
+ struct file *file = iocb->ki_filp;
+ struct cifsFileInfo *cfile = (struct cifsFileInfo *)file->private_data;
+ struct inode *inode = file->f_mapping->host;
+ struct cifsInodeInfo *cinode = CIFS_I(inode);
+ struct TCP_Server_Info *server = tlink_tcon(cfile->tlink)->ses->server;
+ ssize_t rc = -EACCES;
- inode = iocb->ki_filp->f_path.dentry->d_inode;
+ BUG_ON(iocb->ki_pos != pos);
- if (CIFS_I(inode)->clientCanCacheAll)
- return generic_file_aio_write(iocb, iov, nr_segs, pos);
+ sb_start_write(inode->i_sb);
+
+ /*
+ * We need to hold the sem to be sure nobody modifies lock list
+ * with a brlock that prevents writing.
+ */
+ down_read(&cinode->lock_sem);
+ if (!cifs_find_lock_conflict(cfile, pos, iov_length(iov, nr_segs),
+ server->vals->exclusive_lock_type, NULL,
+ true)) {
+ mutex_lock(&inode->i_mutex);
+ rc = __generic_file_aio_write(iocb, iov, nr_segs,
+ &iocb->ki_pos);
+ mutex_unlock(&inode->i_mutex);
+ }
+
+ if (rc > 0 || rc == -EIOCBQUEUED) {
+ ssize_t err;
+
+ err = generic_write_sync(file, pos, rc);
+ if (err < 0 && rc > 0)
+ rc = err;
+ }
+
+ up_read(&cinode->lock_sem);
+ sb_end_write(inode->i_sb);
+ return rc;
+}
+
+ssize_t
+cifs_strict_writev(struct kiocb *iocb, const struct iovec *iov,
+ unsigned long nr_segs, loff_t pos)
+{
+ struct inode *inode = iocb->ki_filp->f_path.dentry->d_inode;
+ struct cifsInodeInfo *cinode = CIFS_I(inode);
+ struct cifs_sb_info *cifs_sb = CIFS_SB(inode->i_sb);
+ struct cifsFileInfo *cfile = (struct cifsFileInfo *)
+ iocb->ki_filp->private_data;
+ struct cifs_tcon *tcon = tlink_tcon(cfile->tlink);
/*
* In strict cache mode we need to write the data to the server exactly
@@ -2411,7 +2459,15 @@ ssize_t cifs_strict_writev(struct kiocb *iocb, const struct iovec *iov,
* not on the region from pos to ppos+len-1.
*/
- return cifs_user_writev(iocb, iov, nr_segs, pos);
+ if (!cinode->clientCanCacheAll)
+ return cifs_user_writev(iocb, iov, nr_segs, pos);
+
+ if (cap_unix(tcon->ses) &&
+ (CIFS_UNIX_FCNTL_CAP & le64_to_cpu(tcon->fsUnixInfo.Capability)) &&
+ ((cifs_sb->mnt_cifs_flags & CIFS_MOUNT_NOPOSIXBRL) == 0))
+ return generic_file_aio_write(iocb, iov, nr_segs, pos);
+
+ return cifs_writev(iocb, iov, nr_segs, pos);
}
static struct cifs_readdata *
@@ -2746,15 +2802,17 @@ ssize_t cifs_user_readv(struct kiocb *iocb, const struct iovec *iov,
return read;
}
-ssize_t cifs_strict_readv(struct kiocb *iocb, const struct iovec *iov,
- unsigned long nr_segs, loff_t pos)
+ssize_t
+cifs_strict_readv(struct kiocb *iocb, const struct iovec *iov,
+ unsigned long nr_segs, loff_t pos)
{
- struct inode *inode;
-
- inode = iocb->ki_filp->f_path.dentry->d_inode;
-
- if (CIFS_I(inode)->clientCanCacheRead)
- return generic_file_aio_read(iocb, iov, nr_segs, pos);
+ struct inode *inode = iocb->ki_filp->f_path.dentry->d_inode;
+ struct cifsInodeInfo *cinode = CIFS_I(inode);
+ struct cifs_sb_info *cifs_sb = CIFS_SB(inode->i_sb);
+ struct cifsFileInfo *cfile = (struct cifsFileInfo *)
+ iocb->ki_filp->private_data;
+ struct cifs_tcon *tcon = tlink_tcon(cfile->tlink);
+ int rc = -EACCES;
/*
* In strict cache mode we need to read from the server all the time
@@ -2764,8 +2822,25 @@ ssize_t cifs_strict_readv(struct kiocb *iocb, const struct iovec *iov,
* on pages affected by this read but not on the region from pos to
* pos+len-1.
*/
+ if (!cinode->clientCanCacheRead)
+ return cifs_user_readv(iocb, iov, nr_segs, pos);
+
+ if (cap_unix(tcon->ses) &&
+ (CIFS_UNIX_FCNTL_CAP & le64_to_cpu(tcon->fsUnixInfo.Capability)) &&
+ ((cifs_sb->mnt_cifs_flags & CIFS_MOUNT_NOPOSIXBRL) == 0))
+ return generic_file_aio_read(iocb, iov, nr_segs, pos);
- return cifs_user_readv(iocb, iov, nr_segs, pos);
+ /*
+ * We need to hold the sem to be sure nobody modifies lock list
+ * with a brlock that prevents reading.
+ */
+ down_read(&cinode->lock_sem);
+ if (!cifs_find_lock_conflict(cfile, pos, iov_length(iov, nr_segs),
+ tcon->ses->server->vals->shared_lock_type,
+ NULL, true))
+ rc = generic_file_aio_read(iocb, iov, nr_segs, pos);
+ up_read(&cinode->lock_sem);
+ return rc;
}
static ssize_t
--
1.7.1
--
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