diff options
| author | Ronnie Sahlberg | 2019-06-05 10:38:38 +1000 |
|---|---|---|
| committer | Steve French | 2019-06-13 14:21:09 -0500 |
| commit | 487317c99477d00f22370625d53be3239febabbe (patch) | |
| tree | a6da1276cdc7abd0870f9eda758115c8912f930e /fs/cifs | |
| parent | 0ff2b018b02f89da26a616e0148582321a00fd99 (diff) | |
cifs: add spinlock for the openFileList to cifsInodeInfo
We can not depend on the tcon->open_file_lock here since in multiuser mode
we may have the same file/inode open via multiple different tcons.
The current code is race prone and will crash if one user deletes a file
at the same time a different user opens/create the file.
To avoid this we need to have a spinlock attached to the inode and not the tcon.
RHBZ: 1580165
CC: Stable <stable@vger.kernel.org>
Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Reviewed-by: Pavel Shilovsky <pshilov@microsoft.com>
Diffstat (limited to 'fs/cifs')
| -rw-r--r-- | fs/cifs/cifsfs.c | 1 | ||||
| -rw-r--r-- | fs/cifs/cifsglob.h | 5 | ||||
| -rw-r--r-- | fs/cifs/file.c | 8 |
3 files changed, 12 insertions, 2 deletions
diff --git a/fs/cifs/cifsfs.c b/fs/cifs/cifsfs.c index f5fcd6360056..65d9771e49f9 100644 --- a/fs/cifs/cifsfs.c +++ b/fs/cifs/cifsfs.c @@ -303,6 +303,7 @@ cifs_alloc_inode(struct super_block *sb) cifs_inode->uniqueid = 0; cifs_inode->createtime = 0; cifs_inode->epoch = 0; + spin_lock_init(&cifs_inode->open_file_lock); generate_random_uuid(cifs_inode->lease_key); /* diff --git a/fs/cifs/cifsglob.h b/fs/cifs/cifsglob.h index 334ff5f9c3f3..4777b3c4a92c 100644 --- a/fs/cifs/cifsglob.h +++ b/fs/cifs/cifsglob.h @@ -1377,6 +1377,7 @@ struct cifsInodeInfo { struct rw_semaphore lock_sem; /* protect the fields above */ /* BB add in lists for dirty pages i.e. write caching info for oplock */ struct list_head openFileList; + spinlock_t open_file_lock; /* protects openFileList */ __u32 cifsAttrs; /* e.g. DOS archive bit, sparse, compressed, system */ unsigned int oplock; /* oplock/lease level we have */ unsigned int epoch; /* used to track lease state changes */ @@ -1780,10 +1781,14 @@ require use of the stronger protocol */ * 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 + * inode->open_file_lock protects the openFileList hanging off the inode * 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 * + * Note that the cifs_tcon.open_file_lock should be taken before + * not after the cifsInodeInfo.open_file_lock + * * Semaphores * ---------- * sesSem operations on smb session diff --git a/fs/cifs/file.c b/fs/cifs/file.c index 06e27ac6d82c..97090693d182 100644 --- a/fs/cifs/file.c +++ b/fs/cifs/file.c @@ -338,10 +338,12 @@ cifs_new_fileinfo(struct cifs_fid *fid, struct file *file, atomic_inc(&tcon->num_local_opens); /* if readable file instance put first in list*/ + spin_lock(&cinode->open_file_lock); if (file->f_mode & FMODE_READ) list_add(&cfile->flist, &cinode->openFileList); else list_add_tail(&cfile->flist, &cinode->openFileList); + spin_unlock(&cinode->open_file_lock); spin_unlock(&tcon->open_file_lock); if (fid->purge_cache) @@ -413,7 +415,9 @@ void _cifsFileInfo_put(struct cifsFileInfo *cifs_file, bool wait_oplock_handler) cifs_add_pending_open_locked(&fid, cifs_file->tlink, &open); /* remove it from the lists */ + spin_lock(&cifsi->open_file_lock); list_del(&cifs_file->flist); + spin_unlock(&cifsi->open_file_lock); list_del(&cifs_file->tlist); atomic_dec(&tcon->num_local_opens); @@ -1950,9 +1954,9 @@ refind_writable: return 0; } - spin_lock(&tcon->open_file_lock); + spin_lock(&cifs_inode->open_file_lock); list_move_tail(&inv_file->flist, &cifs_inode->openFileList); - spin_unlock(&tcon->open_file_lock); + spin_unlock(&cifs_inode->open_file_lock); cifsFileInfo_put(inv_file); ++refind; inv_file = NULL; |