On Wed, 30 Oct 2013 14:48:38 +0400
Pavel Shilovsky <piastry@xxxxxxxxxxx> wrote:
> 2013/10/30 Jeff Layton <jlayton@xxxxxxxxxx>:
> > On Wed, 30 Oct 2013 11:46:22 +0400
> > Pavel Shilovsky <piastry@xxxxxxxxxxx> wrote:
> >
> >> 2013/10/29 Jeff Layton <jlayton@xxxxxxxxxx>:
> >> > On Wed, 23 Oct 2013 18:42:54 +0400
> >> > Pavel Shilovsky <piastry@xxxxxxxxxxx> wrote:
> >> >
> >> >> I created a slightly tested patch below but can't test with deduplicated files now.
> >> >>
> >> >> Joao, can you check if it fixes your problem, please?
> >> >>
> >> >> --------------------------------------------------------------------------
> >> >>
> >> >> Distinguish reparse point types into two groups:
> >> >> 1) that can be accessed directly through a reparse point
> >> >> (junctions, deduplicated files, NFS symlinks);
> >> >> 2) that need to be processed manually (Windows symbolic links, DFS).
> >> >>
> >> >> In this case we map only Windows symbolic links to Unix ones.
> >> >>
> >> >> Signed-off-by: Pavel Shilovsky <piastry@xxxxxxxxxxx>
> >> >> ---
> >> >> fs/cifs/cifsglob.h | 2 +-
> >> >> fs/cifs/inode.c | 23 +++++++++++++----------
> >> >> fs/cifs/readdir.c | 40 ++++++++--------------------------------
> >> >> fs/cifs/smb1ops.c | 27 ++++++++++++++++++++++-----
> >> >> fs/cifs/smb2inode.c | 15 +++++++++++----
> >> >> fs/cifs/smb2proto.h | 2 +-
> >> >> 6 files changed, 56 insertions(+), 53 deletions(-)
> >> >>
> >> >> diff --git a/fs/cifs/cifsglob.h b/fs/cifs/cifsglob.h
> >> >> index a67cf12..b688f2b 100644
> >> >> --- a/fs/cifs/cifsglob.h
> >> >> +++ b/fs/cifs/cifsglob.h
> >> >> @@ -261,7 +261,7 @@ struct smb_version_operations {
> >> >> /* query path data from the server */
> >> >> int (*query_path_info)(const unsigned int, struct cifs_tcon *,
> >> >> struct cifs_sb_info *, const char *,
> >> >> - FILE_ALL_INFO *, bool *);
> >> >> + FILE_ALL_INFO *, bool *, bool *);
> >> >> /* query file data from the server */
> >> >> int (*query_file_info)(const unsigned int, struct cifs_tcon *,
> >> >> struct cifs_fid *, FILE_ALL_INFO *);
> >> >> diff --git a/fs/cifs/inode.c b/fs/cifs/inode.c
> >> >> index 867b7cd..36f9ebb 100644
> >> >> --- a/fs/cifs/inode.c
> >> >> +++ b/fs/cifs/inode.c
> >> >> @@ -542,7 +542,8 @@ static int cifs_sfu_mode(struct cifs_fattr *fattr, const unsigned char *path,
> >> >> /* Fill a cifs_fattr struct with info from FILE_ALL_INFO */
> >> >> static void
> >> >> cifs_all_info_to_fattr(struct cifs_fattr *fattr, FILE_ALL_INFO *info,
> >> >> - struct cifs_sb_info *cifs_sb, bool adjust_tz)
> >> >> + struct cifs_sb_info *cifs_sb, bool adjust_tz,
> >> >> + bool symlink)
> >> >> {
> >> >> struct cifs_tcon *tcon = cifs_sb_master_tcon(cifs_sb);
> >> >>
> >> >> @@ -569,7 +570,11 @@ cifs_all_info_to_fattr(struct cifs_fattr *fattr, FILE_ALL_INFO *info,
> >> >> fattr->cf_createtime = le64_to_cpu(info->CreationTime);
> >> >>
> >> >> fattr->cf_nlink = le32_to_cpu(info->NumberOfLinks);
> >> >> - if (fattr->cf_cifsattrs & ATTR_DIRECTORY) {
> >> >> +
> >> >> + if (symlink) {
> >> >> + fattr->cf_mode = S_IFLNK;
> >> >> + fattr->cf_dtype = DT_LNK;
> >> >> + } else if (fattr->cf_cifsattrs & ATTR_DIRECTORY) {
> >> >> fattr->cf_mode = S_IFDIR | cifs_sb->mnt_dir_mode;
> >> >> fattr->cf_dtype = DT_DIR;
> >> >> /*
> >> >> @@ -578,10 +583,6 @@ cifs_all_info_to_fattr(struct cifs_fattr *fattr, FILE_ALL_INFO *info,
> >> >> */
> >> >> if (!tcon->unix_ext)
> >> >> fattr->cf_flags |= CIFS_FATTR_UNKNOWN_NLINK;
> >> >> - } else if (fattr->cf_cifsattrs & ATTR_REPARSE) {
> >> >> - fattr->cf_mode = S_IFLNK;
> >> >> - fattr->cf_dtype = DT_LNK;
> >> >> - fattr->cf_nlink = le32_to_cpu(info->NumberOfLinks);
> >> >> } else {
> >> >> fattr->cf_mode = S_IFREG | cifs_sb->mnt_file_mode;
> >> >> fattr->cf_dtype = DT_REG;
> >> >> @@ -626,7 +627,8 @@ cifs_get_file_info(struct file *filp)
> >> >> rc = server->ops->query_file_info(xid, tcon, &cfile->fid, &find_data);
> >> >> switch (rc) {
> >> >> case 0:
> >> >> - cifs_all_info_to_fattr(&fattr, &find_data, cifs_sb, false);
> >> >> + cifs_all_info_to_fattr(&fattr, &find_data, cifs_sb, false,
> >> >> + false);
> >> >> break;
> >> >> case -EREMOTE:
> >> >> cifs_create_dfs_fattr(&fattr, inode->i_sb);
> >> >> @@ -673,6 +675,7 @@ cifs_get_inode_info(struct inode **inode, const char *full_path,
> >> >> bool adjust_tz = false;
> >> >> struct cifs_fattr fattr;
> >> >> struct cifs_search_info *srchinf = NULL;
> >> >> + bool symlink = false;
> >> >>
> >> >> tlink = cifs_sb_tlink(cifs_sb);
> >> >> if (IS_ERR(tlink))
> >> >> @@ -702,12 +705,12 @@ cifs_get_inode_info(struct inode **inode, const char *full_path,
> >> >> }
> >> >> data = (FILE_ALL_INFO *)buf;
> >> >> rc = server->ops->query_path_info(xid, tcon, cifs_sb, full_path,
> >> >> - data, &adjust_tz);
> >> >> + data, &adjust_tz, &symlink);
> >> >> }
> >> >>
> >> >> if (!rc) {
> >> >> - cifs_all_info_to_fattr(&fattr, (FILE_ALL_INFO *)data, cifs_sb,
> >> >> - adjust_tz);
> >> >> + cifs_all_info_to_fattr(&fattr, data, cifs_sb, adjust_tz,
> >> >> + symlink);
> >> >> } else if (rc == -EREMOTE) {
> >> >> cifs_create_dfs_fattr(&fattr, sb);
> >> >> rc = 0;
> >> >> diff --git a/fs/cifs/readdir.c b/fs/cifs/readdir.c
> >> >> index 53a75f3..5940eca 100644
> >> >> --- a/fs/cifs/readdir.c
> >> >> +++ b/fs/cifs/readdir.c
> >> >> @@ -134,22 +134,6 @@ out:
> >> >> dput(dentry);
> >> >> }
> >> >>
> >> >> -/*
> >> >> - * Is it possible that this directory might turn out to be a DFS referral
> >> >> - * once we go to try and use it?
> >> >> - */
> >> >> -static bool
> >> >> -cifs_dfs_is_possible(struct cifs_sb_info *cifs_sb)
> >> >> -{
> >> >> -#ifdef CONFIG_CIFS_DFS_UPCALL
> >> >> - struct cifs_tcon *tcon = cifs_sb_master_tcon(cifs_sb);
> >> >> -
> >> >> - if (tcon->Flags & SMB_SHARE_IS_IN_DFS)
> >> >> - return true;
> >> >> -#endif
> >> >> - return false;
> >> >> -}
> >> >> -
> >> >> static void
> >> >> cifs_fill_common_info(struct cifs_fattr *fattr, struct cifs_sb_info *cifs_sb)
> >> >> {
> >> >> @@ -159,27 +143,19 @@ cifs_fill_common_info(struct cifs_fattr *fattr, struct cifs_sb_info *cifs_sb)
> >> >> if (fattr->cf_cifsattrs & ATTR_DIRECTORY) {
> >> >> fattr->cf_mode = S_IFDIR | cifs_sb->mnt_dir_mode;
> >> >> fattr->cf_dtype = DT_DIR;
> >> >> - /*
> >> >> - * Windows CIFS servers generally make DFS referrals look
> >> >> - * like directories in FIND_* responses with the reparse
> >> >> - * attribute flag also set (since DFS junctions are
> >> >> - * reparse points). We must revalidate at least these
> >> >> - * directory inodes before trying to use them (if
> >> >> - * they are DFS we will get PATH_NOT_COVERED back
> >> >> - * when queried directly and can then try to connect
> >> >> - * to the DFS target)
> >> >> - */
> >> >> - if (cifs_dfs_is_possible(cifs_sb) &&
> >> >> - (fattr->cf_cifsattrs & ATTR_REPARSE))
> >> >> - fattr->cf_flags |= CIFS_FATTR_NEED_REVAL;
> >> >> - } else if (fattr->cf_cifsattrs & ATTR_REPARSE) {
> >> >> - fattr->cf_mode = S_IFLNK;
> >> >> - fattr->cf_dtype = DT_LNK;
> >> >> } else {
> >> >> fattr->cf_mode = S_IFREG | cifs_sb->mnt_file_mode;
> >> >> fattr->cf_dtype = DT_REG;
> >> >> }
> >> >>
> >> >> + /*
> >> >> + * We need to revalidate it further to make a decision about whether it
> >> >> + * 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)
> >> >> + fattr->cf_flags |= CIFS_FATTR_NEED_REVAL;
> >> >> +
> >> >> /* non-unix readdir doesn't provide nlink */
> >> >> fattr->cf_flags |= CIFS_FATTR_UNKNOWN_NLINK;
> >> >>
> >> >> diff --git a/fs/cifs/smb1ops.c b/fs/cifs/smb1ops.c
> >> >> index ea99efe..3bb41cf 100644
> >> >> --- a/fs/cifs/smb1ops.c
> >> >> +++ b/fs/cifs/smb1ops.c
> >> >> @@ -534,26 +534,43 @@ cifs_is_path_accessible(const unsigned int xid, struct cifs_tcon *tcon,
> >> >> static int
> >> >> cifs_query_path_info(const unsigned int xid, struct cifs_tcon *tcon,
> >> >> struct cifs_sb_info *cifs_sb, const char *full_path,
> >> >> - FILE_ALL_INFO *data, bool *adjustTZ)
> >> >> + FILE_ALL_INFO *data, bool *adjustTZ, bool *symlink)
> >> >> {
> >> >> int rc;
> >> >> + int oplock = 0;
> >> >> + __u16 netfid;
> >> >> +
> >> >> + rc = CIFSSMBOpen(xid, tcon, full_path, FILE_OPEN, FILE_READ_ATTRIBUTES,
> >> >> + 0, &netfid, &oplock, NULL, cifs_sb->local_nls,
> >> >> + cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MAP_SPECIAL_CHR);
> >> >> + if (rc == -EOPNOTSUPP) {
> >> >> + *symlink = true;
> >> >> + /* Failed on a symbolic link - query a reparse point info */
> >> >> + rc = CIFSSMBOpen(xid, tcon, full_path, FILE_OPEN,
> >> >> + FILE_READ_ATTRIBUTES, OPEN_REPARSE_POINT,
> >> >> + &netfid, &oplock, NULL, cifs_sb->local_nls,
> >> >> + cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MAP_SPECIAL_CHR);
> >> >> + }
> >> >> +
> >> >> + if (!rc) {
> >> >> + rc = CIFSSMBQFileInfo(xid, tcon, netfid, data);
> >> >> + CIFSSMBClose(xid, tcon, netfid);
> >> >> + }
> >> >
> >> > Blech...
> >> >
> >> > So basically for any normal, non-symlink file you'll end up breaking
> >> > any oplocks that might be held just by stat()'ing it? I sincerely hope
> >> > there's a better way to solve this problem...
> >> >
> >>
> >> No, we don't break any oplocks/leases here. Open with READ_ATTRIBUTES
> >> access doesn't force the server to break oplocks. Note, that SMB2.0
> >> protocol has been already doing stat with open-query-close mechanism
> >> that cause no influence to oplocks/leases held by other clients.
> >>
> >> Citing MSDN (http://msdn.microsoft.com/en-us/library/windows/hardware/ff548639(v=vs.85).aspx):
> >> "Note When processing IRP_MJ_CREATE for any oplock, if the desired
> >> access contains nothing other than FILE_READ_ATTRIBUTES,
> >> FILE_WRITE_ATTRIBUTES, or SYNCHRONIZE, the oplock does not break
> >> unless FILE_RESERVE_OPFILTER is specified."
> >>
> >
> > That's good at least, but it is still ugly. Plus, with this change will
> > triple the number of round trips to the server, which will cause
> > performance issues. I think you really want to avoid doing this unless
> > you properly redesign this to use a compound.
>
> While I agree with merging these three commands into a compound
> request, I don't think that we should add it during the stable phase.
> The approach proposed by this patch will bring a performance penalty,
> of course, but it will be only on non-Unix shares with an application
> doing 'stat' on many files.
>
Which is a common workload on our most common deployment scenario.
> Another possibility is to query file attributes with QpathInfo and
> check if it's a reparse point. If no - return as usual. If yes - do
> open-close to determine if the reparse point is symbolic link or not.
> In this case we will not get a performance penalty for normal files
> but will use 3 commands for every reparse points.
>
That sounds like a better option even if it isn't as elegant as it
could be. Reparse points aren't terribly common and we shouldn't
optimize the code for them.
--
Jeff Layton <jlayton@xxxxxxxxxx>
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