Functions gfs2_file_read_iter and gfs2_file_write_iter are both
accessing the user buffer to write to or read from while holding the
inode glock. In the most basic scenario, that buffer will not be
resident and it will be mapped to the same file. Accessing the buffer
will trigger a page fault, and gfs2 will deadlock trying to take the
same inode glock again while trying to handle that fault.
Fix that and similar, more complex scenarios by disabling page faults
while accessing user buffers. To make this work, introduce a small
amount of new infrastructure and fix some bugs that didn't trigger so
far, with page faults enabled.
-----BEGIN PGP SIGNATURE-----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=WeNd
-----END PGP SIGNATURE-----
Merge tag 'gfs2-v5.15-rc5-mmap-fault' of git://git.kernel.org/pub/scm/linux/kernel/git/gfs2/linux-gfs2
Pull gfs2 mmap + page fault deadlocks fixes from Andreas Gruenbacher:
"Functions gfs2_file_read_iter and gfs2_file_write_iter are both
accessing the user buffer to write to or read from while holding the
inode glock.
In the most basic deadlock scenario, that buffer will not be resident
and it will be mapped to the same file. Accessing the buffer will
trigger a page fault, and gfs2 will deadlock trying to take the same
inode glock again while trying to handle that fault.
Fix that and similar, more complex scenarios by disabling page faults
while accessing user buffers. To make this work, introduce a small
amount of new infrastructure and fix some bugs that didn't trigger so
far, with page faults enabled"
* tag 'gfs2-v5.15-rc5-mmap-fault' of git://git.kernel.org/pub/scm/linux/kernel/git/gfs2/linux-gfs2:
gfs2: Fix mmap + page fault deadlocks for direct I/O
iov_iter: Introduce nofault flag to disable page faults
gup: Introduce FOLL_NOFAULT flag to disable page faults
iomap: Add done_before argument to iomap_dio_rw
iomap: Support partial direct I/O on user copy failures
iomap: Fix iomap_dio_rw return value for user copies
gfs2: Fix mmap + page fault deadlocks for buffered I/O
gfs2: Eliminate ip->i_gh
gfs2: Move the inode glock locking to gfs2_file_buffered_write
gfs2: Introduce flag for glock holder auto-demotion
gfs2: Clean up function may_grant
gfs2: Add wrapper for iomap_file_buffered_write
iov_iter: Introduce fault_in_iov_iter_writeable
iov_iter: Turn iov_iter_fault_in_readable into fault_in_iov_iter_readable
gup: Turn fault_in_pages_{readable,writeable} into fault_in_{readable,writeable}
powerpc/kvm: Fix kvm_use_magic_page
iov_iter: Fix iov_iter_get_pages{,_alloc} page fault return value
Turn iov_iter_fault_in_readable into a function that returns the number
of bytes not faulted in, similar to copy_to_user, instead of returning a
non-zero value when any of the requested pages couldn't be faulted in.
This supports the existing users that require all pages to be faulted in
as well as new users that are happy if any pages can be faulted in.
Rename iov_iter_fault_in_readable to fault_in_iov_iter_readable to make
sure this change doesn't silently break things.
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Move inode_to_bdi out of line to avoid having to include blkdev.h.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/20210920123328.1399408-4-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
FALLOC_FL_PUNCH_HOLE isn't allowed with normal files.
Filesystem must remember info about hole, but for normal file
we can only zero it and forget.
Fixes: 4342306f0f ("fs/ntfs3: Add file operations and implementation")
Now xfstests generic/016 generic/021 generic/022 pass.
Signed-off-by: Konstantin Komarov <almaz.alexandrovich@paragon-software.com>
We have lot of unnecessary headers in these files. Remove them so that
we help compiler a little bit.
Signed-off-by: Kari Argillander <kari.argillander@gmail.com>
Signed-off-by: Konstantin Komarov <almaz.alexandrovich@paragon-software.com>
Rename mount option no_acs_rules to (no)acsrules. This allow us to use
possibility to mount with options noaclrules or aclrules.
Acked-by: Christian Brauner <christian.brauner@ubuntu.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Kari Argillander <kari.argillander@gmail.com>
Signed-off-by: Konstantin Komarov <almaz.alexandrovich@paragon-software.com>
Use pointer to mount options. We want to do this because we will use new
mount api which will benefit that we have spi and mount options in
different allocations. When we remount we do not have to make whole new
spi it is enough that we will allocate just mount options.
Please note that we can do example remount lot cleaner but things will
change in next patch so this should be just functional.
Signed-off-by: Kari Argillander <kari.argillander@gmail.com>
Signed-off-by: Konstantin Komarov <almaz.alexandrovich@paragon-software.com>
This check will be also performed in generic_file_read_iter() so we do
not want to check this two times in a row.
This was founded with Smatch
fs/ntfs3/file.c:803 ntfs_file_read_iter()
warn: unused return: count = iov_iter_count()
Signed-off-by: Kari Argillander <kari.argillander@gmail.com>
Signed-off-by: Konstantin Komarov <almaz.alexandrovich@paragon-software.com>
Use fiemap_prep() to check valid flags. It also shrink request scope
(@len) to what the fs can actually handle.
This address following Smatch static checker warning:
fs/ntfs3/frecord.c:1894 ni_fiemap()
warn: potential integer overflow from user 'vbo + len'
Because fiemap_prep() shrinks @len this cannot happened anymore.
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Link: lore.kernel.org/ntfs3/20210825080440.GA17407@kili/
Fixes: 4342306f0f ("fs/ntfs3: Add file operations and implementation")
Signed-off-by: Kari Argillander <kari.argillander@gmail.com>
Signed-off-by: Konstantin Komarov <almaz.alexandrovich@paragon-software.com>
For some reason we have FAT ioctl calls. Even old ntfs driver did not
use these. We should not use these because it his hard to get things out
of kernel when they are upstream. That's why we remove these for now.
More discussion is needed what ioctl should be implemented and what is
important.
Signed-off-by: Kari Argillander <kari.argillander@gmail.com>
Signed-off-by: Konstantin Komarov <almaz.alexandrovich@paragon-software.com>
Capitalize comments and end with period for better reading.
Also function comments are now little more kernel-doc style. This way we
can easily convert them to kernel-doc style if we want. Note that these
are not yet complete with this style. Example function comments start
with /* and in kernel-doc style they start /**.
Use imperative mood in function descriptions.
Change words like ntfs -> NTFS, linux -> Linux.
Use "we" not "I" when commenting code.
Signed-off-by: Kari Argillander <kari.argillander@gmail.com>
Signed-off-by: Konstantin Komarov <almaz.alexandrovich@paragon-software.com>
Use kcalloc/kmalloc_array over kzalloc/kmalloc when we allocate array.
Checkpatch found these after we did not use our own defined allocation
wrappers.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Kari Argillander <kari.argillander@gmail.com>
Signed-off-by: Konstantin Komarov <almaz.alexandrovich@paragon-software.com>
Problem with these wrapper is that we cannot take off example GFP_NOFS
flag. It is not recomended use those in all places. Also if we change
one driver specific wrapper to kernel wrapper then it would look really
weird. People should be most familiar with kernel wrappers so let's just
use those ones.
Driver specific alloc wrapper also confuse some static analyzing tools,
good example is example kernels checkpatch tool. After we converter
these to kernel specific then warnings is showed.
Following Coccinelle script was used to automate changing.
virtual patch
@alloc depends on patch@
expression x;
expression y;
@@
(
- ntfs_malloc(x)
+ kmalloc(x, GFP_NOFS)
|
- ntfs_zalloc(x)
+ kzalloc(x, GFP_NOFS)
|
- ntfs_vmalloc(x)
+ kvmalloc(x, GFP_NOFS)
|
- ntfs_free(x)
+ kfree(x)
|
- ntfs_vfree(x)
+ kvfree(x)
|
- ntfs_memdup(x, y)
+ kmemdup(x, y, GFP_NOFS)
)
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Kari Argillander <kari.argillander@gmail.com>
Signed-off-by: Konstantin Komarov <almaz.alexandrovich@paragon-software.com>
Linus Torvalds