* [PATCH] cifs: Optimize readdir on reparse points
@ 2019-12-19 13:56 Paulo Alcantara (SUSE)
0 siblings, 0 replies; only message in thread
From: Paulo Alcantara (SUSE) @ 2019-12-19 13:56 UTC (permalink / raw)
To: smfrench; +Cc: linux-cifs, Paulo Alcantara (SUSE), Pavel Shilovsky
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>
---
fs/cifs/cifsglob.h | 1 +
fs/cifs/readdir.c | 63 +++++++++++++++++++++++++++++++++++++++-------
2 files changed, 55 insertions(+), 9 deletions(-)
diff --git a/fs/cifs/cifsglob.h b/fs/cifs/cifsglob.h
index ce9bac756c2a..40705e862451 100644
--- a/fs/cifs/cifsglob.h
+++ b/fs/cifs/cifsglob.h
@@ -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)
diff --git a/fs/cifs/readdir.c b/fs/cifs/readdir.c
index 3925a7bfc74d..d17587c2c4ab 100644
--- a/fs/cifs/readdir.c
+++ b/fs/cifs/readdir.c
@@ -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,
--
2.24.0
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