replace open-coded instances
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Signed-off-by: NMiklos Szeredi <mszeredi@suse.cz>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Signed-off-by: NMiklos Szeredi <mszeredi@suse.cz>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Author: David Jeffery <djeffery@redhat.com>
Changes to the basic direct I/O code have broken the raw driver when reading
to the end of a raw device.  Instead of returning a short read for a read that
extends partially beyond the device's end or 0 when at the end of the device,
these reads now return EIO.

The raw driver needs the same end of device handling as was added for normal
block devices.  Using blkdev_read_iter, which has the needed size checks,
prevents the EIO conditions at the end of the device.
Signed-off-by: NDavid Jeffery <djeffery@redhat.com>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

we only need it for joliet and case-insensitive mounts
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

In an overlay directory that shadows an empty lower directory, say
/mnt/a/empty102, do:

 	touch /mnt/a/empty102/x
 	unlink /mnt/a/empty102/x
 	rmdir /mnt/a/empty102

It's actually harmless, but needs another level of nesting between
I_MUTEX_CHILD and I_MUTEX_NORMAL.
Signed-off-by: NMiklos Szeredi <mszeredi@suse.cz>
Tested-by: NDavid Howells <dhowells@redhat.com>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

ovl_cache_entry.name is now an array not a pointer, so it makes no sense
test for it being NULL.

Detected by coverity.

From: Miklos Szeredi <mszeredi@suse.cz>
Fixes: 68bf8611 ("overlayfs: make ovl_cache_entry->name an array instead of
+pointer")
Signed-off-by: NMiklos Szeredi <mszeredi@suse.cz>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

make sure that
	a) all stores done by opening struct file don't leak past storing
the reference in od->upperfile
	b) the lockless side has read dependency barrier
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

same story...
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

no sense having it a pointer - all instances have it pointing to
local variable in the same stack frame
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

just use it to serialize the assignment
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

d_splice_alias() callers expect it to either stash the inode reference
into a new alias, or drop the inode reference.  That makes it possible
to just return d_splice_alias() result from ->lookup() instance, without
any extra housekeeping required.

Unfortunately, that should include the failure exits.  If d_splice_alias()
returns an error, it leaves the dentry it has been given negative and
thus it *must* drop the inode reference.  Easily fixed, but it goes way
back and will need backporting.

Cc: stable@vger.kernel.org
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Add a simple read-only counter to super_block that indicates how deep this
is in the stack of filesystems.  Previously ecryptfs was the only stackable
filesystem and it explicitly disallowed multiple layers of itself.

Overlayfs, however, can be stacked recursively and also may be stacked
on top of ecryptfs or vice versa.

To limit the kernel stack usage we must limit the depth of the
filesystem stack.  Initially the limit is set to 2.
Signed-off-by: NMiklos Szeredi <mszeredi@suse.cz>

This is useful because of the stacking nature of overlayfs.  Users like to
find out (via /proc/mounts) which lower/upper directory were used at mount
time.

AV: even failing ovl_parse_opt() could've done some kstrdup()
AV: failure of ovl_alloc_entry() should end up with ENOMEM, not EINVAL
Signed-off-by: NErez Zadok <ezk@cs.sunysb.edu>
Signed-off-by: NMiklos Szeredi <mszeredi@suse.cz>

Add support for statfs to the overlayfs filesystem.  As the upper layer
is the target of all write operations assume that the space in that
filesystem is the space in the overlayfs.  There will be some inaccuracy as
overwriting a file will copy it up and consume space we were not expecting,
but it is better than nothing.

Use the upper layer dentry and mount from the overlayfs root inode,
passing the statfs call to that filesystem.
Signed-off-by: NAndy Whitcroft <apw@canonical.com>
Signed-off-by: NMiklos Szeredi <mszeredi@suse.cz>

Overlayfs allows one, usually read-write, directory tree to be
overlaid onto another, read-only directory tree.  All modifications
go to the upper, writable layer.

This type of mechanism is most often used for live CDs but there's a
wide variety of other uses.

The implementation differs from other "union filesystem"
implementations in that after a file is opened all operations go
directly to the underlying, lower or upper, filesystems.  This
simplifies the implementation and allows native performance in these
cases.

The dentry tree is duplicated from the underlying filesystems, this
enables fast cached lookups without adding special support into the
VFS.  This uses slightly more memory than union mounts, but dentries
are relatively small.

Currently inodes are duplicated as well, but it is a possible
optimization to share inodes for non-directories.

Opening non directories results in the open forwarded to the
underlying filesystem.  This makes the behavior very similar to union
mounts (with the same limitations vs. fchmod/fchown on O_RDONLY file
descriptors).

Usage:

  mount -t overlayfs overlayfs -olowerdir=/lower,upperdir=/upper/upper,workdir=/upper/work /overlay

The following cotributions have been folded into this patch:

Neil Brown <neilb@suse.de>:
 - minimal remount support
 - use correct seek function for directories
 - initialise is_real before use
 - rename ovl_fill_cache to ovl_dir_read

Felix Fietkau <nbd@openwrt.org>:
 - fix a deadlock in ovl_dir_read_merged
 - fix a deadlock in ovl_remove_whiteouts

Erez Zadok <ezk@fsl.cs.sunysb.edu>
 - fix cleanup after WARN_ON

Sedat Dilek <sedat.dilek@googlemail.com>
 - fix up permission to confirm to new API

Robin Dong <hao.bigrat@gmail.com>
 - fix possible leak in ovl_new_inode
 - create new inode in ovl_link

Andy Whitcroft <apw@canonical.com>
 - switch to __inode_permission()
 - copy up i_uid/i_gid from the underlying inode

AV:
 - ovl_copy_up_locked() - dput(ERR_PTR(...)) on two failure exits
 - ovl_clear_empty() - one failure exit forgetting to do unlock_rename(),
   lack of check for udir being the parent of upper, dropping and regaining
   the lock on udir (which would require _another_ check for parent being
   right).
 - bogus d_drop() in copyup and rename [fix from your mail]
 - copyup/remove and copyup/rename races [fix from your mail]
 - ovl_dir_fsync() leaving ERR_PTR() in ->realfile
 - ovl_entry_free() is pointless - it's just a kfree_rcu()
 - fold ovl_do_lookup() into ovl_lookup()
 - manually assigning ->d_op is wrong.  Just use ->s_d_op.
 [patches picked from Miklos]:
 * copyup/remove and copyup/rename races
 * bogus d_drop() in copyup and rename

Also thanks to the following people for testing and reporting bugs:

  Jordi Pujol <jordipujolp@gmail.com>
  Andy Whitcroft <apw@canonical.com>
  Michal Suchanek <hramrach@centrum.cz>
  Felix Fietkau <nbd@openwrt.org>
  Erez Zadok <ezk@fsl.cs.sunysb.edu>
  Randy Dunlap <rdunlap@xenotime.net>
Signed-off-by: NMiklos Szeredi <mszeredi@suse.cz>

Add whiteout support to ext4_rename().  A whiteout inode (chrdev/0,0) is
created before the rename takes place.  The whiteout inode is added to the
old entry instead of deleting it.
Signed-off-by: NMiklos Szeredi <mszeredi@suse.cz>

This adds a new RENAME_WHITEOUT flag.  This flag makes rename() create a
whiteout of source.  The whiteout creation is atomic relative to the
rename.
Signed-off-by: NMiklos Szeredi <mszeredi@suse.cz>

Whiteout isn't actually a new file type, but is represented as a char
device (Linus's idea) with 0/0 device number.

This has several advantages compared to introducing a new whiteout file
type:

 - no userspace API changes (e.g. trivial to make backups of upper layer
   filesystem, without losing whiteouts)

 - no fs image format changes (you can boot an old kernel/fsck without
   whiteout support and things won't break)

 - implementation is trivial
Signed-off-by: NMiklos Szeredi <mszeredi@suse.cz>

It's already duplicated in btrfs and about to be used in overlayfs too.

Move the sticky bit check to an inline helper and call the out-of-line
helper only in the unlikly case of the sticky bit being set.
Signed-off-by: NMiklos Szeredi <mszeredi@suse.cz>

Overlayfs needs a private clone of the mount, so create a function for
this and export to modules.
Signed-off-by: NMiklos Szeredi <mszeredi@suse.cz>

We need to be able to check inode permissions (but not filesystem implied
permissions) for stackable filesystems.  Expose this interface for overlayfs.
Signed-off-by: NMiklos Szeredi <mszeredi@suse.cz>

Export do_splice_direct() to modules.  Needed by overlay filesystem.
Signed-off-by: NMiklos Szeredi <mszeredi@suse.cz>

Add a new inode operation i_op->dentry_open().  This is for stacked filesystems
that want to return a struct file from a different filesystem.
Signed-off-by: NMiklos Szeredi <mszeredi@suse.cz>

I no longer have access to the Panasas email.
So change to an email that can always reach me.
Signed-off-by: NBoaz Harrosh <ooo@electrozaur.com>

Signed-off-by: NSteven French <smfrench@gmail.com>

This reverts commit 9c3b306e.

Switching only one commit root during a transaction is wrong because it
leads the fs into an inconsistent state. All commit roots should be
switched at once, at transaction commit time, otherwise backref walking
can often miss important references that were only accessible through
the old commit root.  Plus, the root item for the snapshot's root wasn't
getting updated and preventing the next transaction commit to do it.

This made several users get into random corruption issues after creation
of readonly snapshots.

A regression test for xfstests will follow soon.

Cc: stable@vger.kernel.org # 3.17
Signed-off-by: NFilipe Manana <fdmanana@suse.com>
Signed-off-by: NChris Mason <clm@fb.com>

Acked-by: NShirish Pargaonkar <shirishpargaonkar@gmail.com>
Signed-off-by: NSteve French <smfrench@gmail.com>

Mac server returns that they support CIFS Unix Extensions but
doesn't actually support QUERY_FILE_UNIX_BASIC so mount fails.

Workaround this problem by disabling use of Unix CIFS protocol
extensions if server returns an EOPNOTSUPP error on
QUERY_FILE_UNIX_BASIC during mount.
Signed-off-by: NSteve French <smfrench@gmail.com>

This is a bigger patch, but its size is mostly due to
a single change for how we check for remapping illegal characters
in file names - a lot of repeated, small changes to
the way callers request converting file names.

The final patch in the series does the following:

1) changes default behavior for cifs to be more intuitive.
Currently we do not map by default to seven reserved characters,
ie those valid in POSIX but not in NTFS/CIFS/SMB3/Windows,
unless a mount option (mapchars) is specified.  Change this
to by default always map and map using the SFM maping
(like the Mac uses) unless the server negotiates the CIFS Unix
Extensions (like Samba does when mounting with the cifs protocol)
when the remapping of the characters is unnecessary.  This should
help SMB3 mounts in particular since Samba will likely be
able to implement this mapping with its new "vfs_fruit" module
as it will be doing for the Mac.
2) if the user specifies the existing "mapchars" mount option then
use the "SFU" (Microsoft Services for Unix, SUA) style mapping of
the seven characters instead.
3) if the user specifies "nomapposix" then disable SFM/MAC style mapping
(so no character remapping would be used unless the user specifies
"mapchars" on mount as well, as above).
4) change all the places in the code that check for the superblock
flag on the mount which is set by mapchars and passed in on all
path based operation and change it to use a small function call
instead to set the mapping type properly (and check for the
mapping type in the cifs unicode functions)
Signed-off-by: NSteve French <smfrench@gmail.com>

The previous patch allowed remapping reserved characters from directory
listenings, this patch adds conversion the other direction, allowing
opening of files with any of the seven reserved characters.
Signed-off-by: NSteve French <smfrench@gmail.com>
Reviewed-by: NShirish Pargaonkar <shirishpargaonkar@gmail.com>

This allows directory listings to Mac to display filenames
correctly which have been created with illegal (to Windows)
characters in their filename. It does not allow
converting the other direction yet ie opening files with
these characters (followon patch).

There are seven reserved characters that need to be remapped when
mounting to Windows, Mac (or any server without Unix Extensions) which
are valid in POSIX but not in the other OS.

: \ < > ? * |

We used the normal UCS-2 remap range for this in order to convert this
to/from UTF8 as did Windows Services for Unix (basically add 0xF000 to
any of the 7 reserved characters), at least when the "mapchars" mount
option was specified.

Mac used a very slightly different "Services for Mac" remap range
0xF021 through 0xF027.  The attached patch allows cifs.ko (the kernel
client) to read directories on macs containing files with these
characters and display their names properly.  In theory this even
might be useful on mounts to Samba when the vfs_catia or new
"vfs_fruit" module is loaded.

Currently the 7 reserved characters look very strange in directory
listings from cifs.ko to Mac server.  This patch allows these file
name characters to be read (requires specifying mapchars on mount).

Two additional changes are needed:
1) Make it more automatic: a way of detecting enough info so that
we know to try to always remap these characters or not. Various
have suggested that the SFM approach be made the default when
the server does not support POSIX Unix extensions (cifs mounts
to Samba for example) so need to make SFM remapping the default
unless mapchars (SFU style mapping) specified on mount or no
mapping explicitly requested or no mapping needed (cifs mounts to Samba).

2) Adding a patch to map the characters the other direction
(ie UTF-8 to UCS-2 on open).  This patch does it for translating
readdir entries (ie UCS-2 to UTF-8)
Signed-off-by: NSteve French <smfrench@gmail.com>
Reviewed-by: NShirish Pargaonkar <shirishpargaonkar@gmail.com>

Adds support on SMB2.1 and SMB3 mounts for emulation of symlinks
via the "Minshall/French" symlink format already used for cifs
mounts when mfsymlinks mount option is used (and also used by Apple).
  http://wiki.samba.org/index.php/UNIX_Extensions#Minshall.2BFrench_symlinks
This second patch adds support to query them (recognize them as symlinks
and read them).  Third version of patch makes minor corrections
to error handling.
Signed-off-by: NSteve French <smfrench@gmail.com>
Reviewed-by: NStefan Metzmacher <metze@samba.org>

Adds support on SMB2.1 and SMB3 mounts for emulation of symlinks
via the "Minshall/French" symlink format already used for cifs
mounts when mfsymlinks mount option is used (and also used by Apple).
http://wiki.samba.org/index.php/UNIX_Extensions#Minshall.2BFrench_symlinks
This first patch adds support to create them.  The next patch will
add support for recognizing them and reading them.  Although CIFS/SMB3
have other types of symlinks, in the many use cases they aren't
practical (e.g. either require cifs only mounts with unix extensions
to Samba, or require the user to be Administrator to Windows for SMB3).
This also helps enable running additional xfstests over SMB3 (since some
xfstests directly or indirectly require symlink support).
Signed-off-by: NSteve French <smfrench@gmail.com>
CC: Stefan Metzmacher <metze@samba.org>

The "sfu" mount option did not work on SMB2/SMB3 mounts.
With these changes when the "sfu" mount option is passed in
on an smb2/smb2.1/smb3 mount the client can emulate (and
recognize) fifo and device (character and device files).

In addition the "sfu" mount option should not conflict
with "mfsymlinks" (symlink emulation) as we will never
create "sfu" style symlinks, but using "sfu" mount option
will allow us to recognize existing symlinks, created with
Microsoft "Services for Unix" (SFU and SUA).

To enable the "sfu" mount option for SMB2/SMB3 the calling
syntax of the generic cifs/smb2/smb3 sync_read and sync_write
protocol dependent function needed to be changed (we
don't have a file struct in all cases), but this actually
ended up simplifying the code a little.
Signed-off-by: NSteve French <smfrench@gmail.com>

Signed-off-by: NSteve French <smfrench@gmail.com>
Reviewed-by: NShirish Pargaonkar <shirishpargaonkar@gmail.com>

Signed-off-by: NAnton Altaparmakov <anton@tuxera.com>

Signed-off-by: NAnton Altaparmakov <anton@tuxera.com>