linux.git/fs/sync.c, branch v6.6.131

riscv: compat: syscall: Add compat_sys_call_table implementation

2022-04-26T20:36:25+00:00

Implement compat sys_call_table and some system call functions:
truncate64, ftruncate64, fallocate, pread64, pwrite64,
sync_file_range, readahead, fadvise64_64 which need argument
translation.

Signed-off-by: Guo Ren 
Signed-off-by: Guo Ren 
Reviewed-by: Arnd Bergmann 
Tested-by: Heiko Stuebner 
Link: https://lore.kernel.org/r/20220405071314.3225832-12-guoren@kernel.org
Signed-off-by: Palmer Dabbelt

vfs: make sync_filesystem return errors from ->sync_fs

2022-01-30T16:59:47+00:00

Strangely, sync_filesystem ignores the return code from the ->sync_fs
call, which means that syscalls like syncfs(2) never see the error.
This doesn't seem right, so fix that.

Signed-off-by: Darrick J. Wong 
Reviewed-by: Jan Kara 
Reviewed-by: Christoph Hellwig 
Acked-by: Christian Brauner

block: simplify the block device syncing code

2021-10-22T14:36:55+00:00

Get rid of the indirections and just provide a sync_bdevs
helper for the generic sync code.

Signed-off-by: Christoph Hellwig 
Link: https://lore.kernel.org/r/20211019062530.2174626-8-hch@lst.de
Signed-off-by: Jens Axboe

block: remove __sync_blockdev

2021-10-22T14:36:55+00:00

Instead offer a new sync_blockdev_nowait helper for the !wait case.
This new helper is exported as it will grow modular callers in a bit.

Signed-off-by: Christoph Hellwig 
Link: https://lore.kernel.org/r/20211019062530.2174626-3-hch@lst.de
Signed-off-by: Jens Axboe

fs: remove __sync_filesystem

2021-10-22T14:36:55+00:00

There is no clear benefit in having this helper vs just open coding it.

Signed-off-by: Christoph Hellwig 
Reviewed-by: Chaitanya Kulkarni 
Link: https://lore.kernel.org/r/20211019062530.2174626-2-hch@lst.de
Signed-off-by: Jens Axboe

Merge tag 'ovl-update-5.8' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs

2020-06-09T22:40:50+00:00

Pull overlayfs updates from Miklos Szeredi:
 "Fixes:

   - Resolve mount option conflicts consistently

   - Sync before remount R/O

   - Fix file handle encoding corner cases

   - Fix metacopy related issues

   - Fix an unintialized return value

   - Add missing permission checks for underlying layers

  Optimizations:

   - Allow multipe whiteouts to share an inode

   - Optimize small writes by inheriting SB_NOSEC from upper layer

   - Do not call ->syncfs() multiple times for sync(2)

   - Do not cache negative lookups on upper layer

   - Make private internal mounts longterm"

* tag 'ovl-update-5.8' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs: (27 commits)
  ovl: remove unnecessary lock check
  ovl: make oip->index bool
  ovl: only pass ->ki_flags to ovl_iocb_to_rwf()
  ovl: make private mounts longterm
  ovl: get rid of redundant members in struct ovl_fs
  ovl: add accessor for ofs->upper_mnt
  ovl: initialize error in ovl_copy_xattr
  ovl: drop negative dentry in upper layer
  ovl: check permission to open real file
  ovl: call secutiry hook in ovl_real_ioctl()
  ovl: verify permissions in ovl_path_open()
  ovl: switch to mounter creds in readdir
  ovl: pass correct flags for opening real directory
  ovl: fix redirect traversal on metacopy dentries
  ovl: initialize OVL_UPPERDATA in ovl_lookup()
  ovl: use only uppermetacopy state in ovl_lookup()
  ovl: simplify setting of origin for index lookup
  ovl: fix out of bounds access warning in ovl_check_fb_len()
  ovl: return required buffer size for file handles
  ovl: sync dirty data when remounting to ro mode
  ...

vfs: track per-sb writeback errors and report them to syncfs

2020-06-02T17:59:05+00:00

Patch series "vfs: have syncfs() return error when there are writeback
errors", v6.

Currently, syncfs does not return errors when one of the inodes fails to
be written back.  It will return errors based on the legacy AS_EIO and
AS_ENOSPC flags when syncing out the block device fails, but that's not
particularly helpful for filesystems that aren't backed by a blockdev.
It's also possible for a stray sync to lose those errors.

The basic idea in this set is to track writeback errors at the
superblock level, so that we can quickly and easily check whether
something bad happened without having to fsync each file individually.
syncfs is then changed to reliably report writeback errors after they
occur, much in the same fashion as fsync does now.

This patch (of 2):

Usually we suggest that applications call fsync when they want to ensure
that all data written to the file has made it to the backing store, but
that can be inefficient when there are a lot of open files.

Calling syncfs on the filesystem can be more efficient in some
situations, but the error reporting doesn't currently work the way most
people expect.  If a single inode on a filesystem reports a writeback
error, syncfs won't necessarily return an error.  syncfs only returns an
error if __sync_blockdev fails, and on some filesystems that's a no-op.

It would be better if syncfs reported an error if there were any
writeback failures.  Then applications could call syncfs to see if there
are any errors on any open files, and could then call fsync on all of
the other descriptors to figure out which one failed.

This patch adds a new errseq_t to struct super_block, and has
mapping_set_error also record writeback errors there.

To report those errors, we also need to keep an errseq_t in struct file
to act as a cursor.  This patch adds a dedicated field for that purpose,
which slots nicely into 4 bytes of padding at the end of struct file on
x86_64.

An earlier version of this patch used an O_PATH file descriptor to cue
the kernel that the open file should track the superblock error and not
the inode's writeback error.

I think that API is just too weird though.  This is simpler and should
make syncfs error reporting "just work" even if someone is multiplexing
fsync and syncfs on the same fds.

Signed-off-by: Jeff Layton 
Signed-off-by: Andrew Morton 
Reviewed-by: Jan Kara 
Cc: Andres Freund 
Cc: Matthew Wilcox 
Cc: Al Viro 
Cc: Christoph Hellwig 
Cc: Dave Chinner 
Cc: David Howells 
Link: http://lkml.kernel.org/r/20200428135155.19223-1-jlayton@kernel.org
Link: http://lkml.kernel.org/r/20200428135155.19223-2-jlayton@kernel.org
Signed-off-by: Linus Torvalds

ovl: skip overlayfs superblocks at global sync

2020-05-13T09:11:24+00:00

Stacked filesystems like overlayfs has no own writeback, but they have to
forward syncfs() requests to backend for keeping data integrity.

During global sync() each overlayfs instance calls method ->sync_fs() for
backend although it itself is in global list of superblocks too.  As a
result one syscall sync() could write one superblock several times and send
multiple disk barriers.

This patch adds flag SB_I_SKIP_SYNC into sb->sb_iflags to avoid that.

Reported-by: Dmitry Monakhov 
Signed-off-by: Konstantin Khlebnikov 
Reviewed-by: Amir Goldstein 
Signed-off-by: Miklos Szeredi

fs/sync.c: sync_file_range(2) may use WB_SYNC_ALL writeback

2019-05-14T16:47:50+00:00

23d0127096cb ("fs/sync.c: make sync_file_range(2) use WB_SYNC_NONE
writeback") claims that sync_file_range(2) syscall was "created for
userspace to be able to issue background writeout and so waiting for
in-flight IO is undesirable there" and changes the writeback (back) to
WB_SYNC_NONE.

This claim is only partially true.  It is true for users that use the flag
SYNC_FILE_RANGE_WRITE by itself, as does PostgreSQL, the user that was the
reason for changing to WB_SYNC_NONE writeback.

However, that claim is not true for users that use that flag combination
SYNC_FILE_RANGE_{WAIT_BEFORE|WRITE|_WAIT_AFTER}.  Those users explicitly
requested to wait for in-flight IO as well as to writeback of dirty pages.

Re-brand that flag combination as SYNC_FILE_RANGE_WRITE_AND_WAIT and use
WB_SYNC_ALL writeback to perform the full range sync request.

Link: http://lkml.kernel.org/r/20190409114922.30095-1-amir73il@gmail.com
Link: http://lkml.kernel.org/r/20190419072938.31320-1-amir73il@gmail.com
Fixes: 23d0127096cb ("fs/sync.c: make sync_file_range(2) use WB_SYNC_NONE")
Signed-off-by: Amir Goldstein 
Acked-by: Jan Kara 
Cc: Dave Chinner 
Cc: Al Viro 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

fs: add sync_file_range() helper

2019-05-02T20:08:53+00:00

This just pulls out the ksys_sync_file_range() code to work on a struct
file instead of an fd, so we can use it elsewhere.

Signed-off-by: Jens Axboe