kernel/git/stable/linux.git/fs/read_write.c, branch linux-5.8.y

autofs: use __kernel_write() for the autofs pipe writing

2020-10-07T06:02:53+00:00

[ Upstream commit 90fb702791bf99b959006972e8ee7bb4609f441b ] autofs got broken in some configurations by commit 13c164b1a186 ("autofs: switch to kernel_write") because there is now an extra LSM permission check done by security_file_permission() in rw_verify_area(). autofs is one if the few places that really does want the much more limited __kernel_write(), because the write is an internal kernel one that shouldn't do any user permission checks (it also doesn't need the file_start_write/file_end_write logic, since it's just a pipe). There are a couple of other cases like that - accounting, core dumping, and splice - but autofs stands out because it can be built as a module. As a result, we need to export this internal __kernel_write() function again. We really don't want any other module to use this, but we don't have a "EXPORT_SYMBOL_FOR_AUTOFS_ONLY()". But we can mark it GPL-only to at least approximate that "internal use only" for licensing. While in this area, make autofs pass in NULL for the file position pointer, since it's always a pipe, and we now use a NULL file pointer for streaming file descriptors (see file_ppos() and commit 438ab720c675: "vfs: pass ppos=NULL to .read()/.write() of FMODE_STREAM files") This effectively reverts commits 9db977522449 ("fs: unexport __kernel_write") and 13c164b1a186 ("autofs: switch to kernel_write"). Fixes: 13c164b1a186 ("autofs: switch to kernel_write") Reported-by: Ondrej Mosnacek Acked-by: Christoph Hellwig Acked-by: Acked-by: Ian Kent Signed-off-by: Linus Torvalds Signed-off-by: Sasha Levin

fs: remove __vfs_read

2020-07-08T06:27:57+00:00

Fold it into the two callers. Signed-off-by: Christoph Hellwig

fs: implement kernel_read using __kernel_read

2020-07-08T06:27:57+00:00

Consolidate the two in-kernel read helpers to make upcoming changes easier. The only difference are the missing call to rw_verify_area in kernel_read, and an access_ok check that doesn't make sense for kernel buffers to start with. Signed-off-by: Christoph Hellwig

fs: add a __kernel_read helper

2020-07-08T06:27:56+00:00

This is the counterpart to __kernel_write, and skip the rw_verify_area call compared to kernel_read. Signed-off-by: Christoph Hellwig

fs: remove __vfs_write

2020-07-08T06:27:56+00:00

Fold it into the two callers. Signed-off-by: Christoph Hellwig

fs: implement kernel_write using __kernel_write

2020-07-08T06:27:56+00:00

Consolidate the two in-kernel write helpers to make upcoming changes easier. The only difference are the missing call to rw_verify_area in kernel_write, and an access_ok check that doesn't make sense for kernel buffers to start with. Signed-off-by: Christoph Hellwig

fs: check FMODE_WRITE in __kernel_write

2020-07-08T06:27:56+00:00

Add a WARN_ON_ONCE if the file isn't actually open for write. This matches the check done in vfs_write, but actually warn warns as a kernel user calling write on a file not opened for writing is a pretty obvious programming error. Signed-off-by: Christoph Hellwig

fs: unexport __kernel_write

2020-07-08T06:27:56+00:00

This is a very special interface that skips sb_writes protection, and not used by modules anymore. Signed-off-by: Christoph Hellwig

powerpc: Add back __ARCH_WANT_SYS_LLSEEK macro

2020-04-02T13:09:59+00:00

This partially reverts commit caf6f9c8a326 ("asm-generic: Remove unneeded __ARCH_WANT_SYS_LLSEEK macro") When CONFIG_COMPAT is disabled on ppc64 the kernel does not build. There is resistance to both removing the llseek syscall from the 64bit syscall tables and building the llseek interface unconditionally. Signed-off-by: Michal Suchanek Reviewed-by: Arnd Bergmann Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/lkml/20190828151552.GA16855@infradead.org/ Link: https://lore.kernel.org/lkml/20190829214319.498c7de2@naga/ Link: https://lore.kernel.org/r/dd4575c51e31766e87f7e7fa121d099ab78d3290.1584699455.git.msuchanek@suse.de

Merge tag 'ovl-update-5.6' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs

2020-02-04T11:45:21+00:00

Pull overlayfs update from Miklos Szeredi: - Try to preserve holes in sparse files when copying up, thus saving disk space and improving performance. - Fix a performance regression introduced in v4.19 by preserving asynchronicity of IO when fowarding to underlying layers. Add VFS helpers to submit async iocbs. - Fix a regression in lseek(2) introduced in v4.19 that breaks >2G seeks on 32bit kernels. - Fix a corner case where st_ino/st_dev was not preserved across copy up. - Miscellaneous fixes and cleanups. * tag 'ovl-update-5.6' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs: ovl: fix lseek overflow on 32bit ovl: add splice file read write helper ovl: implement async IO routines vfs: add vfs_iocb_iter_[read|write] helper functions ovl: layer is const ovl: fix corner case of non-constant st_dev;st_ino ovl: fix corner case of conflicting lower layer uuid ovl: generalize the lower_fs[] array ovl: simplify ovl_same_sb() helper ovl: generalize the lower_layers[] array ovl: improving copy-up efficiency for big sparse file ovl: use ovl_inode_lock in ovl_llseek() ovl: use pr_fmt auto generate prefix ovl: fix wrong WARN_ON() in ovl_cache_update_ino()