diff mbox series

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

Message ID 20220824002756.3659568-6-lsahlber@redhat.com
State New
Headers show
Series [1/6] cifs: Make tcon contain a wrapper structure cached_fids instead of cached_fid | expand

Commit Message

Ronnie Sahlberg Aug. 24, 2022, 12:27 a.m. UTC
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@redhat.com>
---
 fs/cifs/cached_dir.c | 70 +++++++++++++++++++++++++++++++++++---------
 1 file changed, 56 insertions(+), 14 deletions(-)

Comments

Tom Talpey Aug. 24, 2022, 1:43 p.m. UTC | #1
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@redhat.com>
> ---
>   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@redhat.com>
>    */
>   
> +#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;
ronnie sahlberg Aug. 25, 2022, 4:21 a.m. UTC | #2
On Wed, 24 Aug 2022 at 23:51, Tom Talpey <tom@talpey.com> wrote:
>
> 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@redhat.com>
> > ---
> >   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@redhat.com>
> >    */
> >
> > +#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...

Thanks!
You are right. I have fixed it.

>
> > +
> > +     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?

Done.

>
> > -
> >       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.

Of course.  done.
Thanks.
>
> > +     cfid->tcon = tcon;
> >       cfid->time = jiffies;
> >       cfid->is_open = true;
> >       cfid->has_lease = true;
diff mbox series

Patch

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@redhat.com>
  */
 
+#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);
+
+	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;
-
 	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;
+	}
+	cfid->tcon = tcon;
 	cfid->time = jiffies;
 	cfid->is_open = true;
 	cfid->has_lease = true;