Commit e4029e07 authored by Ronnie Sahlberg's avatar Ronnie Sahlberg Committed by Steve French
Browse files

cifs: find and use the dentry for cached non-root directories also 



This allows us to use cached attributes for the entries in a cached
directory for as long as a lease is held on the directory itself.
Previously we have always allowed "used cached attributes for 1 second"
but this extends this to the lifetime of the lease as well as making the
caching safer.

Signed-off-by: default avatarRonnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: default avatarSteve French <stfrench@microsoft.com>
parent ebe98f14

fs/cifs/cached_dir.c

+49 −14
Original line number Diff line number Diff line
@@ -5,6 +5,7 @@ 
 *  Copyright (c) 2022, Ronnie Sahlberg <lsahlber@redhat.com>

 */



#include <linux/namei.h>

#include "cifsglob.h"

#include "cifsproto.h"

#include "cifs_debug.h"
@@ -59,6 +60,44 @@ static struct cached_fid *find_or_create_cached_dir(struct cached_fids *cfids, 
	return cfid;

}



static struct dentry *

path_to_dentry(struct cifs_sb_info *cifs_sb, const char *path)

{

	struct dentry *dentry;

	const char *s, *p;

	char sep;



	sep = CIFS_DIR_SEP(cifs_sb);

	dentry = dget(cifs_sb->root);

	s = path;



	do {

		struct inode *dir = d_inode(dentry);

		struct dentry *child;



		if (!S_ISDIR(dir->i_mode)) {

			dput(dentry);

			dentry = ERR_PTR(-ENOTDIR);

			break;

		}



		/* skip separators */

		while (*s == sep)

			s++;

		if (!*s)

			break;

		p = s++;

		/* next separator */

		while (*s && *s != sep)

			s++;



		child = lookup_positive_unlocked(p, dentry, s - p);

		dput(dentry);

		dentry = child;

	} while (!IS_ERR(dentry));

	return dentry;

}



/*

 * Open the and cache a directory handle.

 * If error then *cfid is not initialized.
@@ -86,7 +125,6 @@ int open_cached_dir(unsigned int xid, struct cifs_tcon *tcon, 
	struct cached_fid *cfid;

	struct cached_fids *cfids;





	if (tcon == NULL || tcon->cfids == NULL || tcon->nohandlecache ||

	    is_smb1_server(tcon->ses->server))

		return -EOPNOTSUPP;
@@ -101,13 +139,6 @@ int open_cached_dir(unsigned int xid, struct cifs_tcon *tcon, 
	if (cifs_sb->root == NULL)

		return -ENOENT;



	/*

	 * TODO: for better caching we need to find and use the dentry also

	 * for non-root directories.

	 */

	if (!path[0])

		dentry = cifs_sb->root;



	utf16_path = cifs_convert_path_to_utf16(path, cifs_sb);

	if (!utf16_path)

		return -ENOMEM;
@@ -199,12 +230,6 @@ int open_cached_dir(unsigned int xid, struct cifs_tcon *tcon, 
	oparms.fid->mid = le64_to_cpu(o_rsp->hdr.MessageId);

#endif /* CIFS_DEBUG2 */



	cfid->tcon = tcon;

	if (dentry) {

		cfid->dentry = dentry;

		dget(dentry);

	}

	/* BB TBD check to see if oplock level check can be removed below */

	if (o_rsp->OplockLevel != SMB2_OPLOCK_LEVEL_LEASE)

		goto oshr_free;
@@ -223,6 +248,16 @@ int open_cached_dir(unsigned int xid, struct cifs_tcon *tcon, 
				&rsp_iov[1], sizeof(struct smb2_file_all_info),

				(char *)&cfid->file_all_info))

		cfid->file_all_info_is_valid = true;



	if (!path[0])

		dentry = dget(cifs_sb->root);

	else {

		dentry = path_to_dentry(cifs_sb, path);

		if (IS_ERR(dentry))

			goto oshr_free;

	}

	cfid->dentry = dentry;

	cfid->tcon = tcon;

	cfid->time = jiffies;

	cfid->is_open = true;

	cfid->has_lease = true;