Re: [PATCH 07/12] statx: CIFS: Return enhanced attributes

[Steve French <smfrench@gmail.com>]

Is it worth storing the same creation time twice (in slightly
different formats, struct timespec and u64 DCE time) in cifsInodeInfo?

On Fri, Nov 20, 2015 at 8:55 AM, David Howells <dhowells@redhat.com> wrote:
> Return enhanced attributes from the CIFS filesystem.  This includes the
> following:
>
>  (1) Return the file creation time as btime.  We assume that the creation
>      time won't change over the life of the inode.
>
>  (2) Set STATX_INFO_AUTOMOUNT on referral/submount directories.
>
>  (3) Unset STATX_INO if we made up the inode number and didn't get it from
>      the server.
>
>  (4) Unset STATX_[UG]ID if we are either returning values passed to mount
>      and/or the server doesn't return them.
>
>  (5) Set STATX_IOC_FLAGS and map various Windows file attributes to
>      FS_xxx_FL flags in st_ioc_flags, fetching them from the server if we
>      don't have them yet or don't have a current copy.  This includes the
>      following:
>
>         ATTR_READONLY   -> FS_IMMUTABLE_FL
>         ATTR_COMPRESSED -> FS_COMPR_FL
>         ATTR_HIDDEN     -> FS_HIDDEN_FL
>         ATTR_SYSTEM     -> FS_SYSTEM_FL
>         ATTR_ARCHIVE    -> FS_ARCHIVE_FL
>
>  (6) Set certain STATX_INFO_xxx to reflect other Windows file attributes:
>
>         ATTR_TEMPORARY  -> STATX_INFO_TEMPORARY;
>         ATTR_REPARSE    -> STATX_INFO_REPARSE_POINT;
>         ATTR_OFFLINE    -> STATX_INFO_OFFLINE;
>         ATTR_ENCRYPTED  -> STATX_INFO_ENCRYPTED;
>
>  (7) Set STATX_INFO_REMOTE on all files fetched by CIFS.
>
>  (8) Set STATX_INFO_NONSYSTEM_OWNERSHIP on all files as they all have
>      Windows ownership details too.
>
> Furthermore, what cifs_getattr() does can be controlled as follows:
>
>  (1) If AT_NO_ATTR_SYNC is indicated then this will suppress the flushing
>      of outstanding writes and the rereading of the inode's attributes with
>      the server as detailed below.
>
>  (2) Otherwise:
>
>      (a) If AT_FORCE_ATTR_SYNC is indicated, or mtime, ctime or size are
>          requested then the outstanding writes will be written to the
>          server first.
>
>      (b) The inode's attributes will be reread from the server:
>
>          (i) if AT_FORCE_ATTR_SYNC is indicated;
>
>         (ii) if the cached attributes have expired;
>
>        (iii) extra attributes are requested that aren't normally stored.
>
> If the inode isn't synchronised, then the cached attributes will be used -
> even if expired - without reference to the server.  Some attributes may be
> unavailable that would otherwise be provided.
>
> Note that cifs_revalidate_dentry() will issue an extra operation to get the
> FILE_ALL_INFO in addition to the FILE_UNIX_BASIC_INFO if it needs to
> collect creation time and attributes on behalf of cifs_getattr().
>
> [NOTE: THIS PATCH IS UNTESTED!]
>
> Signed-off-by: David Howells <dhowells@redhat.com>
> ---
>
>  fs/cifs/cifsfs.h   |    4 +-
>  fs/cifs/cifsglob.h |    8 +++
>  fs/cifs/dir.c      |    2 -
>  fs/cifs/inode.c    |  124 +++++++++++++++++++++++++++++++++++++++++-----------
>  4 files changed, 108 insertions(+), 30 deletions(-)
>
> diff --git a/fs/cifs/cifsfs.h b/fs/cifs/cifsfs.h
> index c3cc1609025f..fb38d47d84de 100644
> --- a/fs/cifs/cifsfs.h
> +++ b/fs/cifs/cifsfs.h
> @@ -71,9 +71,9 @@ extern int cifs_rmdir(struct inode *, struct dentry *);
>  extern int cifs_rename2(struct inode *, struct dentry *, struct inode *,
>                         struct dentry *, unsigned int);
>  extern int cifs_revalidate_file_attr(struct file *filp);
> -extern int cifs_revalidate_dentry_attr(struct dentry *);
> +extern int cifs_revalidate_dentry_attr(struct dentry *, bool, bool);
>  extern int cifs_revalidate_file(struct file *filp);
> -extern int cifs_revalidate_dentry(struct dentry *);
> +extern int cifs_revalidate_dentry(struct dentry *, bool, bool);
>  extern int cifs_invalidate_mapping(struct inode *inode);
>  extern int cifs_revalidate_mapping(struct inode *inode);
>  extern int cifs_zap_mapping(struct inode *inode);
> diff --git a/fs/cifs/cifsglob.h b/fs/cifs/cifsglob.h
> index b406a32deb1f..493e40a15b86 100644
> --- a/fs/cifs/cifsglob.h
> +++ b/fs/cifs/cifsglob.h
> @@ -1152,7 +1152,11 @@ struct cifsInodeInfo {
>         unsigned long flags;
>         spinlock_t writers_lock;
>         unsigned int writers;           /* Number of writers on this inode */
> +       bool btime_valid:1;             /* stored creation time is valid */
> +       bool uid_faked:1;               /* true if i_uid is faked */
> +       bool gid_faked:1;               /* true if i_gid is faked */
>         unsigned long time;             /* jiffies of last update of inode */
> +       struct timespec btime;          /* creation time */
>         u64  server_eof;                /* current file size on server -- protected by i_lock */
>         u64  uniqueid;                  /* server inode number */
>         u64  createtime;                /* creation time on server */
> @@ -1365,6 +1369,9 @@ struct dfs_info3_param {
>  #define CIFS_FATTR_NEED_REVAL          0x4
>  #define CIFS_FATTR_INO_COLLISION       0x8
>  #define CIFS_FATTR_UNKNOWN_NLINK       0x10
> +#define CIFS_FATTR_WINATTRS_VALID      0x20    /* T if cf_btime and cf_cifsattrs valid */
> +#define CIFS_FATTR_UID_FAKED           0x40    /* T if cf_uid is faked */
> +#define CIFS_FATTR_GID_FAKED           0x80    /* T if cf_gid is faked */
>
>  struct cifs_fattr {
>         u32             cf_flags;
> @@ -1382,6 +1389,7 @@ struct cifs_fattr {
>         struct timespec cf_atime;
>         struct timespec cf_mtime;
>         struct timespec cf_ctime;
> +       struct timespec cf_btime;
>  };
>
>  static inline void free_dfs_info_param(struct dfs_info3_param *param)
> diff --git a/fs/cifs/dir.c b/fs/cifs/dir.c
> index c3eb998a99bd..4984f04b0677 100644
> --- a/fs/cifs/dir.c
> +++ b/fs/cifs/dir.c
> @@ -792,7 +792,7 @@ cifs_d_revalidate(struct dentry *direntry, unsigned int flags)
>                 return -ECHILD;
>
>         if (d_really_is_positive(direntry)) {
> -               if (cifs_revalidate_dentry(direntry))
> +               if (cifs_revalidate_dentry(direntry, false, false))
>                         return 0;
>                 else {
>                         /*
> diff --git a/fs/cifs/inode.c b/fs/cifs/inode.c
> index 6b66dd5d1540..fcb024efbd4b 100644
> --- a/fs/cifs/inode.c
> +++ b/fs/cifs/inode.c
> @@ -166,13 +166,21 @@ cifs_fattr_to_inode(struct inode *inode, struct cifs_fattr *fattr)
>         cifs_nlink_fattr_to_inode(inode, fattr);
>         inode->i_uid = fattr->cf_uid;
>         inode->i_gid = fattr->cf_gid;
> +       if (fattr->cf_flags & CIFS_FATTR_UID_FAKED)
> +               cifs_i->uid_faked = true;
> +       if (fattr->cf_flags & CIFS_FATTR_GID_FAKED)
> +               cifs_i->gid_faked = true;
>
>         /* if dynperm is set, don't clobber existing mode */
>         if (inode->i_state & I_NEW ||
>             !(cifs_sb->mnt_cifs_flags & CIFS_MOUNT_DYNPERM))
>                 inode->i_mode = fattr->cf_mode;
>
> -       cifs_i->cifsAttrs = fattr->cf_cifsattrs;
> +       if (fattr->cf_flags & CIFS_FATTR_WINATTRS_VALID) {
> +               cifs_i->cifsAttrs = fattr->cf_cifsattrs;
> +               cifs_i->btime = fattr->cf_btime;
> +               cifs_i->btime_valid = true;
> +       }
>
>         if (fattr->cf_flags & CIFS_FATTR_NEED_REVAL)
>                 cifs_i->time = 0;
> @@ -284,18 +292,22 @@ cifs_unix_basic_to_fattr(struct cifs_fattr *fattr, FILE_UNIX_BASIC_INFO *info,
>                 u64 id = le64_to_cpu(info->Uid);
>                 if (id < ((uid_t)-1)) {
>                         kuid_t uid = make_kuid(&init_user_ns, id);
> -                       if (uid_valid(uid))
> +                       if (uid_valid(uid)) {
>                                 fattr->cf_uid = uid;
> +                               fattr->cf_flags |= CIFS_FATTR_UID_FAKED;
> +                       }
>                 }
>         }
> -
> +
>         fattr->cf_gid = cifs_sb->mnt_gid;
>         if (!(cifs_sb->mnt_cifs_flags & CIFS_MOUNT_OVERR_GID)) {
>                 u64 id = le64_to_cpu(info->Gid);
>                 if (id < ((gid_t)-1)) {
>                         kgid_t gid = make_kgid(&init_user_ns, id);
> -                       if (gid_valid(gid))
> +                       if (gid_valid(gid)) {
>                                 fattr->cf_gid = gid;
> +                               fattr->cf_flags |= CIFS_FATTR_GID_FAKED;
> +                       }
>                 }
>         }
>
> @@ -324,7 +336,8 @@ cifs_create_dfs_fattr(struct cifs_fattr *fattr, struct super_block *sb)
>         fattr->cf_ctime = CURRENT_TIME;
>         fattr->cf_mtime = CURRENT_TIME;
>         fattr->cf_nlink = 2;
> -       fattr->cf_flags |= CIFS_FATTR_DFS_REFERRAL;
> +       fattr->cf_flags |= CIFS_FATTR_DFS_REFERRAL |
> +               CIFS_FATTR_UID_FAKED | CIFS_FATTR_GID_FAKED;
>  }
>
>  static int
> @@ -590,6 +603,7 @@ cifs_all_info_to_fattr(struct cifs_fattr *fattr, FILE_ALL_INFO *info,
>         struct cifs_tcon *tcon = cifs_sb_master_tcon(cifs_sb);
>
>         memset(fattr, 0, sizeof(*fattr));
> +       fattr->cf_flags = CIFS_FATTR_WINATTRS_VALID;
>         fattr->cf_cifsattrs = le32_to_cpu(info->Attributes);
>         if (info->DeletePending)
>                 fattr->cf_flags |= CIFS_FATTR_DELETE_PENDING;
> @@ -601,6 +615,7 @@ cifs_all_info_to_fattr(struct cifs_fattr *fattr, FILE_ALL_INFO *info,
>
>         fattr->cf_ctime = cifs_NTtimeToUnix(info->ChangeTime);
>         fattr->cf_mtime = cifs_NTtimeToUnix(info->LastWriteTime);
> +       fattr->cf_btime = cifs_NTtimeToUnix(info->CreationTime);
>
>         if (adjust_tz) {
>                 fattr->cf_ctime.tv_sec += tcon->ses->server->timeAdj;
> @@ -1887,7 +1902,8 @@ int cifs_revalidate_file_attr(struct file *filp)
>         return rc;
>  }
>
> -int cifs_revalidate_dentry_attr(struct dentry *dentry)
> +int cifs_revalidate_dentry_attr(struct dentry *dentry,
> +                               bool want_extra_bits, bool force)
>  {
>         unsigned int xid;
>         int rc = 0;
> @@ -1898,7 +1914,7 @@ int cifs_revalidate_dentry_attr(struct dentry *dentry)
>         if (inode == NULL)
>                 return -ENOENT;
>
> -       if (!cifs_inode_needs_reval(inode))
> +       if (!force && !cifs_inode_needs_reval(inode))
>                 return rc;
>
>         xid = get_xid();
> @@ -1915,9 +1931,12 @@ int cifs_revalidate_dentry_attr(struct dentry *dentry)
>                  full_path, inode, inode->i_count.counter,
>                  dentry, dentry->d_time, jiffies);
>
> -       if (cifs_sb_master_tcon(CIFS_SB(sb))->unix_ext)
> +       if (cifs_sb_master_tcon(CIFS_SB(sb))->unix_ext) {
>                 rc = cifs_get_inode_info_unix(&inode, full_path, sb, xid);
> -       else
> +               if (rc != 0)
> +                       goto out;
> +       }
> +       if (!cifs_sb_master_tcon(CIFS_SB(sb))->unix_ext || want_extra_bits)
>                 rc = cifs_get_inode_info(&inode, full_path, NULL, sb,
>                                          xid, NULL);
>
> @@ -1940,12 +1959,13 @@ int cifs_revalidate_file(struct file *filp)
>  }
>
>  /* revalidate a dentry's inode attributes */
> -int cifs_revalidate_dentry(struct dentry *dentry)
> +int cifs_revalidate_dentry(struct dentry *dentry,
> +                          bool want_extra_bits, bool force)
>  {
>         int rc;
>         struct inode *inode = d_inode(dentry);
>
> -       rc = cifs_revalidate_dentry_attr(dentry);
> +       rc = cifs_revalidate_dentry_attr(dentry, want_extra_bits, force);
>         if (rc)
>                 return rc;
>
> @@ -1958,28 +1978,62 @@ int cifs_getattr(struct vfsmount *mnt, struct dentry *dentry,
>         struct cifs_sb_info *cifs_sb = CIFS_SB(dentry->d_sb);
>         struct cifs_tcon *tcon = cifs_sb_master_tcon(cifs_sb);
>         struct inode *inode = d_inode(dentry);
> +       struct cifsInodeInfo *cifs_i = CIFS_I(inode);
> +       bool force = stat->query_flags & AT_FORCE_ATTR_SYNC;
> +       bool want_extra_bits = false;
> +       u32 info, ioc = 0;
> +       u32 attrs;
>         int rc;
>
> -       /*
> -        * We need to be sure that all dirty pages are written and the server
> -        * has actual ctime, mtime and file length.
> -        */
> -       if (!CIFS_CACHE_READ(CIFS_I(inode)) && inode->i_mapping &&
> -           inode->i_mapping->nrpages != 0) {
> -               rc = filemap_fdatawait(inode->i_mapping);
> -               if (rc) {
> -                       mapping_set_error(inode->i_mapping, rc);
> -                       return rc;
> +       if (cifs_i->uid_faked)
> +               stat->request_mask &= ~STATX_UID;
> +       if (cifs_i->gid_faked)
> +               stat->request_mask &= ~STATX_GID;
> +
> +       if ((stat->request_mask & STATX_BTIME && !cifs_i->btime_valid) ||
> +           stat->request_mask & STATX_IOC_FLAGS)
> +               want_extra_bits = force = true;
> +
> +       if (!(stat->query_flags & AT_NO_ATTR_SYNC)) {
> +               /* Unless we're explicitly told not to sync, we need to be sure
> +                * that all dirty pages are written and the server has actual
> +                * ctime, mtime and file length.
> +                */
> +               bool flush = force;
> +
> +               if (stat->request_mask &
> +                   (STATX_CTIME | STATX_MTIME | STATX_SIZE))
> +                       flush = true;
> +
> +               if (flush &&
> +                   !CIFS_CACHE_READ(CIFS_I(inode)) && inode->i_mapping &&
> +                   inode->i_mapping->nrpages != 0) {
> +                       rc = filemap_fdatawait(inode->i_mapping);
> +                       if (rc) {
> +                               mapping_set_error(inode->i_mapping, rc);
> +                               return rc;
> +                       }
>                 }
> -       }
>
> -       rc = cifs_revalidate_dentry_attr(dentry);
> -       if (rc)
> -               return rc;
> +               rc = cifs_revalidate_dentry(dentry, want_extra_bits, force);
> +               if (rc)
> +                       return rc;
> +       }
>
>         generic_fillattr(inode, stat);
>         stat->blksize = CIFS_MAX_MSGSIZE;
> -       stat->ino = CIFS_I(inode)->uniqueid;
> +
> +       info = STATX_INFO_REMOTE | STATX_INFO_NONSYSTEM_OWNERSHIP;
> +
> +       if (cifs_i->btime_valid) {
> +               stat->btime = cifs_i->btime;
> +               stat->result_mask |= STATX_BTIME;
> +       }
> +
> +       /* We don't promise an inode number if we made one up */
> +       stat->ino = cifs_i->uniqueid;
> +       if (!(cifs_sb->mnt_cifs_flags & CIFS_MOUNT_SERVER_INUM))
> +               stat->result_mask &= ~STATX_INO;
>
>         /*
>          * If on a multiuser mount without unix extensions or cifsacl being
> @@ -1993,8 +2047,24 @@ int cifs_getattr(struct vfsmount *mnt, struct dentry *dentry,
>                         stat->uid = current_fsuid();
>                 if (!(cifs_sb->mnt_cifs_flags & CIFS_MOUNT_OVERR_GID))
>                         stat->gid = current_fsgid();
> +               stat->result_mask &= ~(STATX_UID | STATX_GID);
>         }
> -       return rc;
> +
> +       attrs = cifs_i->cifsAttrs;
> +       if (attrs & ATTR_TEMPORARY)     info |= STATX_INFO_TEMPORARY;
> +       if (attrs & ATTR_REPARSE)       info |= STATX_INFO_REPARSE_POINT;
> +       if (attrs & ATTR_OFFLINE)       info |= STATX_INFO_OFFLINE;
> +       if (attrs & ATTR_ENCRYPTED)     info |= STATX_INFO_ENCRYPTED;
> +       stat->information |= info;
> +
> +       if (attrs & ATTR_READONLY)      ioc |= FS_IMMUTABLE_FL;
> +       if (attrs & ATTR_COMPRESSED)    ioc |= FS_COMPR_FL;
> +       if (attrs & ATTR_HIDDEN)        ioc |= FS_HIDDEN_FL;
> +       if (attrs & ATTR_SYSTEM)        ioc |= FS_SYSTEM_FL;
> +       if (attrs & ATTR_ARCHIVE)       ioc |= FS_ARCHIVE_FL;
> +       stat->ioc_flags |= ioc;
> +
> +       return 0;
>  }
>
>  static int cifs_truncate_page(struct address_space *mapping, loff_t from)
>
> --
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-- 
Thanks,

Steve