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cifs: Optimize readdir on reparse points 

When listing a directory with thounsands of files and most of them are
reparse points, we simply marked all those dentries for revalidation
and then sending additional (compounded) create/getinfo/close requests
for each of them.

Instead, upon receiving a response from an SMB2_QUERY_DIRECTORY
(FileIdFullDirectoryInformation) command, the directory entries that
have a file attribute of FILE_ATTRIBUTE_REPARSE_POINT will contain an
EaSize field with a reparse tag in it, so we parse it and mark the
dentry for revalidation only if it is a DFS or a symlink.

Signed-off-by: Paulo Alcantara (SUSE) <pc@cjr.nz>
Reviewed-by: Pavel Shilovsky <pshilov@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
This commit is contained in:
Paulo Alcantara (SUSE) 2019-12-18 18:11:37 -03:00 committed by Steve French
parent 7935799e04
commit 046aca3c25
2 changed files with 55 additions and 9 deletions
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1
fs/cifs/cifsglob.h
View File

@ -1693,6 +1693,7 @@ struct cifs_fattr {
struct timespec64 cf_atime;
struct timespec64 cf_mtime;
struct timespec64 cf_ctime;
u32 cf_cifstag;
};
static inline void free_dfs_info_param(struct dfs_info3_param *param)

63
fs/cifs/readdir.c
View File

@ -139,6 +139,28 @@ cifs_prime_dcache(struct dentry *parent, struct qstr *name,
dput(dentry);
}
static bool reparse_file_needs_reval(const struct cifs_fattr *fattr)
{
if (!(fattr->cf_cifsattrs & ATTR_REPARSE))
return false;
/*
* The DFS tags should be only intepreted by server side as per
* MS-FSCC 2.1.2.1, but let's include them anyway.
*
* Besides, if cf_cifstag is unset (0), then we still need it to be
* revalidated to know exactly what reparse point it is.
*/
switch (fattr->cf_cifstag) {
case IO_REPARSE_TAG_DFS:
case IO_REPARSE_TAG_DFSR:
case IO_REPARSE_TAG_SYMLINK:
case IO_REPARSE_TAG_NFS:
case 0:
return true;
}
return false;
}
static void
cifs_fill_common_info(struct cifs_fattr *fattr, struct cifs_sb_info *cifs_sb)
{
@ -158,7 +180,7 @@ cifs_fill_common_info(struct cifs_fattr *fattr, struct cifs_sb_info *cifs_sb)
* is a symbolic link, DFS referral or a reparse point with a direct
* access like junctions, deduplicated files, NFS symlinks.
*/
if (fattr->cf_cifsattrs & ATTR_REPARSE)
if (reparse_file_needs_reval(fattr))
fattr->cf_flags |= CIFS_FATTR_NEED_REVAL;
/* non-unix readdir doesn't provide nlink */
@ -194,19 +216,37 @@ cifs_fill_common_info(struct cifs_fattr *fattr, struct cifs_sb_info *cifs_sb)
}
}
static void __dir_info_to_fattr(struct cifs_fattr *fattr, const void *info)
{
const FILE_DIRECTORY_INFO *fi = info;
memset(fattr, 0, sizeof(*fattr));
fattr->cf_cifsattrs = le32_to_cpu(fi->ExtFileAttributes);
fattr->cf_eof = le64_to_cpu(fi->EndOfFile);
fattr->cf_bytes = le64_to_cpu(fi->AllocationSize);
fattr->cf_createtime = le64_to_cpu(fi->CreationTime);
fattr->cf_atime = cifs_NTtimeToUnix(fi->LastAccessTime);
fattr->cf_ctime = cifs_NTtimeToUnix(fi->ChangeTime);
fattr->cf_mtime = cifs_NTtimeToUnix(fi->LastWriteTime);
}
void
cifs_dir_info_to_fattr(struct cifs_fattr *fattr, FILE_DIRECTORY_INFO *info,
struct cifs_sb_info *cifs_sb)
{
memset(fattr, 0, sizeof(*fattr));
fattr->cf_cifsattrs = le32_to_cpu(info->ExtFileAttributes);
fattr->cf_eof = le64_to_cpu(info->EndOfFile);
fattr->cf_bytes = le64_to_cpu(info->AllocationSize);
fattr->cf_createtime = le64_to_cpu(info->CreationTime);
fattr->cf_atime = cifs_NTtimeToUnix(info->LastAccessTime);
fattr->cf_ctime = cifs_NTtimeToUnix(info->ChangeTime);
fattr->cf_mtime = cifs_NTtimeToUnix(info->LastWriteTime);
__dir_info_to_fattr(fattr, info);
cifs_fill_common_info(fattr, cifs_sb);
}
static void cifs_fulldir_info_to_fattr(struct cifs_fattr *fattr,
SEARCH_ID_FULL_DIR_INFO *info,
struct cifs_sb_info *cifs_sb)
{
__dir_info_to_fattr(fattr, info);
/* See MS-FSCC 2.4.18 FileIdFullDirectoryInformation */
if (fattr->cf_cifsattrs & ATTR_REPARSE)
fattr->cf_cifstag = le32_to_cpu(info->EaSize);
cifs_fill_common_info(fattr, cifs_sb);
}
@ -755,6 +795,11 @@ static int cifs_filldir(char *find_entry, struct file *file,
(FIND_FILE_STANDARD_INFO *)find_entry,
cifs_sb);
break;
case SMB_FIND_FILE_ID_FULL_DIR_INFO:
cifs_fulldir_info_to_fattr(&fattr,
(SEARCH_ID_FULL_DIR_INFO *)find_entry,
cifs_sb);
break;
default:
cifs_dir_info_to_fattr(&fattr,
(FILE_DIRECTORY_INFO *)find_entry,