From: Paulo Alcantara pc@manguebit.com
commit be4fde79812f02914e350bde0bc4cfeae8429378 upstream.
Get rid of any prefix paths in @path before lookup_positive_unlocked() as it will call ->lookup() which already adds those prefix paths through build_path_from_dentry().
This has caused a performance regression when mounting shares with a prefix path where readdir(2) would end up retrying several times to open bad directory names that contained duplicate prefix paths.
Fix this by skipping any prefix paths in @path before calling lookup_positive_unlocked().
Fixes: e4029e072673 ("cifs: find and use the dentry for cached non-root directories also") Cc: stable@vger.kernel.org # 6.1+ Signed-off-by: Paulo Alcantara (SUSE) pc@manguebit.com Signed-off-by: Steve French stfrench@microsoft.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- fs/cifs/cached_dir.c | 36 ++++++++++++++++++++++++++++++++++-- 1 file changed, 34 insertions(+), 2 deletions(-)
--- a/fs/cifs/cached_dir.c +++ b/fs/cifs/cached_dir.c @@ -99,6 +99,23 @@ path_to_dentry(struct cifs_sb_info *cifs return dentry; }
+static const char *path_no_prefix(struct cifs_sb_info *cifs_sb, + const char *path) +{ + size_t len = 0; + + if (!*path) + return path; + + if ((cifs_sb->mnt_cifs_flags & CIFS_MOUNT_USE_PREFIX_PATH) && + cifs_sb->prepath) { + len = strlen(cifs_sb->prepath) + 1; + if (unlikely(len > strlen(path))) + return ERR_PTR(-EINVAL); + } + return path + len; +} + /* * Open the and cache a directory handle. * If error then *cfid is not initialized. @@ -125,6 +142,7 @@ int open_cached_dir(unsigned int xid, st struct dentry *dentry = NULL; struct cached_fid *cfid; struct cached_fids *cfids; + const char *npath;
if (tcon == NULL || tcon->cfids == NULL || tcon->nohandlecache || is_smb1_server(tcon->ses->server)) @@ -161,6 +179,20 @@ int open_cached_dir(unsigned int xid, st }
/* + * Skip any prefix paths in @path as lookup_positive_unlocked() ends up + * calling ->lookup() which already adds those through + * build_path_from_dentry(). Also, do it earlier as we might reconnect + * below when trying to send compounded request and then potentially + * having a different prefix path (e.g. after DFS failover). + */ + npath = path_no_prefix(cifs_sb, path); + if (IS_ERR(npath)) { + rc = PTR_ERR(npath); + kfree(utf16_path); + return rc; + } + + /* * We do not hold the lock for the open because in case * SMB2_open needs to reconnect. * This is safe because no other thread will be able to get a ref @@ -252,10 +284,10 @@ int open_cached_dir(unsigned int xid, st (char *)&cfid->file_all_info)) cfid->file_all_info_is_valid = true;
- if (!path[0]) + if (!npath[0]) dentry = dget(cifs_sb->root); else { - dentry = path_to_dentry(cifs_sb, path); + dentry = path_to_dentry(cifs_sb, npath); if (IS_ERR(dentry)) { rc = -ENOENT; goto oshr_free;