Commit 31602533 authored by Henrique Carvalho's avatar Henrique Carvalho Committed by Steve French
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smb: client: short-circuit negative lookups when parent dir is fully cached 



When the parent directory has a valid and complete cached enumeration we
can assume that negative dentries are not present in the directory, thus
we can return without issuing a request.

This reduces traffic for common ENOENT when the directory entries are
cached.

Signed-off-by: default avatarHenrique Carvalho <henrique.carvalho@suse.com>
Signed-off-by: default avatarSteve French <stfrench@microsoft.com>
parent 55580ad0

fs/smb/client/dir.c

+42 −1
Original line number Diff line number Diff line
@@ -683,6 +683,7 @@ cifs_lookup(struct inode *parent_dir_inode, struct dentry *direntry, 
	const char *full_path;

	void *page;

	int retry_count = 0;

	struct cached_fid *cfid = NULL;



	xid = get_xid();
@@ -722,6 +723,28 @@ cifs_lookup(struct inode *parent_dir_inode, struct dentry *direntry, 
		cifs_dbg(FYI, "non-NULL inode in lookup\n");

	} else {

		cifs_dbg(FYI, "NULL inode in lookup\n");



		/*

		 * We can only rely on negative dentries having the same

		 * spelling as the cached dirent if case insensitivity is

		 * forced on mount.

		 *

		 * XXX: if servers correctly announce Case Sensitivity Search

		 * on GetInfo of FileFSAttributeInformation, then we can take

		 * correct action even if case insensitive is not forced on

		 * mount.

		 */

		if (pTcon->nocase && !open_cached_dir_by_dentry(pTcon, direntry->d_parent, &cfid)) {

			/*

			 * dentry is negative and parent is fully cached:

			 * we can assume file does not exist

			 */

			if (cfid->dirents.is_valid) {

				close_cached_dir(cfid);

				goto out;

			}

			close_cached_dir(cfid);

		}

	}

	cifs_dbg(FYI, "Full path: %s inode = 0x%p\n",

		 full_path, d_inode(direntry));
@@ -755,6 +778,8 @@ cifs_lookup(struct inode *parent_dir_inode, struct dentry *direntry, 
		}

		newInode = ERR_PTR(rc);

	}



out:

	free_dentry_path(page);

	cifs_put_tlink(tlink);

	free_xid(xid);
@@ -765,7 +790,8 @@ static int 
cifs_d_revalidate(struct inode *dir, const struct qstr *name,

		  struct dentry *direntry, unsigned int flags)

{

	struct inode *inode;

	struct inode *inode = NULL;

	struct cached_fid *cfid;

	int rc;



	if (flags & LOOKUP_RCU)
@@ -812,6 +838,21 @@ cifs_d_revalidate(struct inode *dir, const struct qstr *name, 


			return 1;

		}

	} else {

		struct cifs_sb_info *cifs_sb = CIFS_SB(dir->i_sb);

		struct cifs_tcon *tcon = cifs_sb_master_tcon(cifs_sb);



		if (!open_cached_dir_by_dentry(tcon, direntry->d_parent, &cfid)) {

			/*

			 * dentry is negative and parent is fully cached:

			 * we can assume file does not exist

			 */

			if (cfid->dirents.is_valid) {

				close_cached_dir(cfid);

				return 1;

			}

			close_cached_dir(cfid);

		}

	}



	/*