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authorPaulo Alcantara <pc@manguebit.com>2023-03-24 13:56:33 -0300
committerSteve French <stfrench@microsoft.com>2023-03-24 14:37:12 -0500
commitbe4fde79812f02914e350bde0bc4cfeae8429378 (patch)
treeb594a846eaf0e5664c8f8286721620f6e3d895f7 /fs/cifs
parent7e0e76d99079be13c9961dde7c93b2d1ee665af4 (diff)
cifs: fix dentry lookups in directory handle cache
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>
Diffstat (limited to 'fs/cifs')
-rw-r--r--fs/cifs/cached_dir.c36
1 files changed, 34 insertions, 2 deletions
diff --git a/fs/cifs/cached_dir.c b/fs/cifs/cached_dir.c
index 71fabb4c09a4..bfc964b36c72 100644
--- a/fs/cifs/cached_dir.c
+++ b/fs/cifs/cached_dir.c
@@ -99,6 +99,23 @@ path_to_dentry(struct cifs_sb_info *cifs_sb, const char *path)
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, struct cifs_tcon *tcon,
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, struct cifs_tcon *tcon,
}
/*
+ * 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, struct cifs_tcon *tcon,
(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;