When file attributes are changed most filesystems rely on the
setattr_prepare(), setattr_copy(), and notify_change() helpers for
initialization and permission checking. Let them handle idmapped mounts.
If the inode is accessed through an idmapped mount map it into the
mount's user namespace. Afterwards the checks are identical to
non-idmapped mounts. If the initial user namespace is passed nothing
changes so non-idmapped mounts will see identical behavior as before.
Helpers that perform checks on the ia_uid and ia_gid fields in struct
iattr assume that ia_uid and ia_gid are intended values and have already
been mapped correctly at the userspace-kernelspace boundary as we
already do today. If the initial user namespace is passed nothing
changes so non-idmapped mounts will see identical behavior as before.
Link: https://lore.kernel.org/r/20210121131959.646623-8-christian.brauner@ubuntu.com
Cc: Christoph Hellwig <hch@lst.de>
Cc: David Howells <dhowells@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: linux-fsdevel@vger.kernel.org
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
Pull misc vfs updates from Al Viro:
"Assorted stuff all over the place (the largest group here is
Christoph's stat cleanups)"
* 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
fs: remove KSTAT_QUERY_FLAGS
fs: remove vfs_stat_set_lookup_flags
fs: move vfs_fstatat out of line
fs: implement vfs_stat and vfs_lstat in terms of vfs_fstatat
fs: remove vfs_statx_fd
fs: omfs: use kmemdup() rather than kmalloc+memcpy
[PATCH] reduce boilerplate in fsid handling
fs: Remove duplicated flag O_NDELAY occurring twice in VALID_OPEN_FLAGS
selftests: mount: add nosymfollow tests
Add a "nosymfollow" mount option.
Move the struct block_device definition together with most of the
block layer definitions, as it has nothing to do with the rest of fs.h.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This code accidentally returns success, but it should return the
-EIO error code from adfs_fplus_validate_header().
Acked-by: Russell King <rmk+kernel@armlinux.org.uk>
Fixes: d79288b4f6 ("fs/adfs: bigdir: calculate and validate directory checkbyte")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Avoid using the inode number as the indirect disc address, even though
these currently have the same value.
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Add support for ADFS E and E+ floppy image formats, which, unlike their
hard disk variants, do not have a filesystem boot block - they have a
single map zone, with the map fragment stored at sector 0.
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Separate the filesystem block probing from the superblock filling so
we can support other ADFS filesystem formats, such as the single-zone
E and E+ floppy image formats which do not have a boot block.
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
When we have write support enabled, we must not drop inodes before they
have been written back, otherwise we lose updates to the filesystem on
umount. Keep the inodes around unless we are built in read-only mode,
or we are mounted read-only.
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Implement big directory entry update support in the same way that we
do for new directories.
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
When reading a big directory, calculate the validate the directory
checkbyte to ensure that the directory contents are valid.
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Strengthen the directory validation by ensuring that the header fields
contain sensible values that fit inside the directory, and limit the
directory size to 4MB as per RISC OS requirements.
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Extract the directory validation from the directory reading function as
we will want to re-use this code.
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Factor out the directory entry byte offset calculation.
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
After changing a directory, we need to update the sequence numbers and
calculate the new check byte before the directory is scheduled to be
written back to the media. Since this needs to happen for any change
to the directory, move this into a separate method.
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
__adfs_dir_put() and adfs_dir_find_entry() are only called from
adfs_f_update(), so move them into this function, removing some
unnecessary entry copying by doing so.
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
adfs_dir_read() is only called from adfs_f_read(), so merge it into
that function. As new directories are always 2048 bytes in size,
(which we rely on elsewhere) we can consolidate some of the code.
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Check that the lastmask and reserved fields are all zero, as per the
documentation.
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
We have two locations where we validate the new directory format, so
factor this out to a helper.
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Add and use pointers in the adfs_dir structure to access the directory
head and tail structures, which will always be contiguous in a buffer.
This allows us to avoid memcpy()ing the data in the new directory code,
making it slightly more efficient.
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Rather than using setpos + getnext to iterate through the directory
entries, pass iterate() down to the dir format code to populate the
dirents.
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
There is nothing in our readdir (aka iterate) method that relies on
the directory inode being exclusively locked, so switch to using the
iterate_shared() hook rather than iterate().
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Get rid of the ifdef, using IS_ENABLED() instead to detect whether the
code should be callable. This allows the compiler to always parse the
following code, reducing the chances of errors being missed.
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
When we update a directory, a number of errors may happen. If we failed
to find the entry to update, we can just release the directory buffers
as normal.
However, if we have some other error, we may have partially updated the
buffers, resulting in an invalid directory. In this case, we need to
discard the buffers to avoid writing the contents back to the media, and
later re-read the directory from the media.
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Use __u8 and pack the structures for on-disk directories.
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Update directory locking such that it covers the validation of the
directory, which could fail if another thread is concurrently writing
to the same directory. Since we may sleep, we need to use a rwsem
rather than a rw spinlock.
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Provide a helper for marking directory buffers dirty so they get
written back to disk.
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Add a helper to read a directory using the inode, which we do in two
places.
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Both directory formats code the mechanics of fetching the directory
buffers using their own implementations. Consolidate these into one
implementation.
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Directories can span multiple buffers, and we currently open-code
memcpy access to these buffers, including dealing with entries that
are split across multiple buffers. Such code exists in both
directory format implementations.
Provide common functions to allow data to be copied from/to the
directory buffers as if they were a contiguous set of buffers, and
use them when accessing directories.
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
adfs_fplus_sync() can be used for both directory formats since we now
have a common way to access the buffer heads, so move it into dir.c
and appropriately rename it. Remove the directory-format specific
implementations.
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
With the bhs pointer in place, we have no need for separate per-format
free() methods, since a generic version will do. Provide a generic
implementation, remove the format specific implementations and the
method function pointer.
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Initialise the dir object before we pass it down to the directory format
specific read handler. This allows us to get rid of the initialisation
inside those handlers.
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Rename bh_fplus to bhs in preparation to make some of the directory
handling code sharable between implementations.
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
When scanning the map for a fragment id, we need to keep track of the
free space links, so we don't inadvertently believe that the freespace
link is a valid fragment id.
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Move map specific superblock initialisation to map.c, rather than
having it spread into super.c.
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Use find_next_bit_le() to find the end of a fragment in the map rather
than open-coding this functionality.
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
lookup_zone() and scan_free_map() cope in different ways with the
location of the map data within a zone:
1. lookup_zone() adds a four byte offset to the map data pointer to
skip over the check and free link bytes.
2. scan_free_map() needs to use the free link pointer, which is an
offset from itself, so we end up adding a 32-bit offset to the
end pointer (aka mapsize) which is really confusing.
Rename mapsize to endbit as this is really what it is, and incorporate
the 32-bit offset into the map layout. This means that both dm_startbit
and dm_endbit are now bit offsets from the start of the buffer, rather
than four bytes in to the buffer.
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
We have several places which deal with releasing the map buffers and
freeing the map array. Provide a helper for this.
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Split up adfs_read_map() into separate helpers to layout the map,
read the map, and release the map buffers.
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
adfs_map_free() is not obvious whether it is freeing the map or
returning the number of free blocks on the filesystem. Rename it to
the more generic statfs() to make it clear that it's a statistic
function.
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Keep all the map code together in map.c, rather than having some in
super.c
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Fix adfs_mode2atts() to actually update the file permissions on the
media rather than using the current inode mode. Note also that
directories do not have read/write permissions stored on the media.
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Despite ADFS timestamps having centi-second granularity, and Linux
gaining fine-grained timestamp support in v2.5.48, fs/adfs was never
updated.
Update fs/adfs to centi-second support, and ensure that the inode ctime
always reflects what is written in underlying media.
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Pull adfs updates from Al Viro:
"More ADFS patches from Russell King"
* 'work.adfs' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
fs/adfs: add time stamp and file type helpers
fs/adfs: super: limit idlen according to directory type
fs/adfs: super: fix use-after-free bug
fs/adfs: super: safely update options on remount
fs/adfs: super: correct superblock flags
fs/adfs: clean up indirect disc addresses and fragment IDs
fs/adfs: clean up error message printing
fs/adfs: use %pV for error messages
fs/adfs: use format_version from disc_record
fs/adfs: add helper to get filesystem size
fs/adfs: add helper to get discrecord from map
fs/adfs: correct disc record structure
Add some helpers to check whether the inode has a time stamp and file
type, and to parse the file type from the load address.
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Limit idlen according to the directory type, as idlen (the size of a
fragment ID) can not be more than 16 with the "new directory" layout.
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
