Re: [PATCH 5/6] cifs: find and use the dentry for cached non-root directories also

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



On 8/23/2022 8:27 PM, Ronnie Sahlberg wrote:
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: Ronnie Sahlberg <lsahlber@xxxxxxxxxx>
---
  fs/cifs/cached_dir.c | 70 +++++++++++++++++++++++++++++++++++---------
  1 file changed, 56 insertions(+), 14 deletions(-)

diff --git a/fs/cifs/cached_dir.c b/fs/cifs/cached_dir.c
index 8732903aea03..f4d7700827b3 100644
--- a/fs/cifs/cached_dir.c
+++ b/fs/cifs/cached_dir.c
@@ -5,6 +5,7 @@
   *  Copyright (c) 2022, Ronnie Sahlberg <lsahlber@xxxxxxxxxx>
   */
+#include <linux/namei.h>
  #include "cifsglob.h"
  #include "cifsproto.h"
  #include "cifs_debug.h"
@@ -113,6 +114,50 @@ 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 *full_path)
+{
+	struct dentry *dentry;
+	char *path = NULL;
+	char *s, *p;
+	char sep;
+
+	path = kstrdup(full_path, GFP_ATOMIC);
+	if (path == NULL)
+		return ERR_PTR(-ENOMEM);

Why make a copy of the path? I don't see anything in the code
below that modifies its contents...

+
+	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));
+	kfree(path);
+	return dentry;
+}
+
  /*
   * Open the and cache a directory handle.
   * If error then *cfid is not initialized.
@@ -139,7 +184,6 @@ int open_cached_dir(unsigned int xid, struct cifs_tcon *tcon,
  	struct dentry *dentry = NULL;
  	struct cached_fid *cfid;
  	struct cached_fids *cfids;
-	
if (tcon == NULL || tcon->cfids == NULL || tcon->nohandlecache ||
  	    is_smb1_server(tcon->ses->server))
@@ -155,13 +199,6 @@ 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 (!strlen(path))
-		dentry = cifs_sb->root;

Test path[0] instead of calling strlen?

-
  	utf16_path = cifs_convert_path_to_utf16(path, cifs_sb);
  	if (!utf16_path)
  		return -ENOMEM;
@@ -253,12 +290,6 @@ 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;
  	}
@@ -277,6 +308,17 @@ 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 (!strlen(path)) {
+		dentry = dget(cifs_sb->root);
+		cfid->dentry = dentry;
+	} else{
+		dentry = path_to_dentry(cifs_sb, path);
+		if (IS_ERR(dentry))
+			goto oshr_free;
+		cfid->dentry = dentry;
+	}

Pull cfid->dentry = dentry out of the above conditionals and
just set it here for both cases.

+	cfid->tcon = tcon;
  	cfid->time = jiffies;
  	cfid->is_open = true;
  	cfid->has_lease = true;



[Linux USB Devel]     [Video for Linux]     [Linux Audio Users]     [Yosemite News]     [Linux Kernel]     [Linux SCSI]

  Powered by Linux