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| author |   Xiubo Li <xiubli@redhat.com> | 2020-02-03 21:28:25 -0500 |
|---|---|---|
| committer |   Ilya Dryomov <idryomov@gmail.com> | 2020-02-11 17:04:04 +0100 |
| commit | 8e4473bb50a1796c9c32b244e5dbc5ee24ead937 (patch) | |
| tree | 7de41d8d856fcca65497e08059ea660f682295d9 /fs/ceph/file.c | |
| parent | Linux 5.6-rc1 (diff) | |
| download | linux-dev-8e4473bb50a1796c9c32b244e5dbc5ee24ead937.tar.xz linux-dev-8e4473bb50a1796c9c32b244e5dbc5ee24ead937.zip | |
ceph: do not execute direct write in parallel if O_APPEND is specified
In O_APPEND & O_DIRECT mode, the data from different writers will
be possibly overlapping each other since they take the shared lock.
For example, both Writer1 and Writer2 are in O_APPEND and O_DIRECT
mode:
Writer1 Writer2
shared_lock() shared_lock()
getattr(CAP_SIZE) getattr(CAP_SIZE)
iocb->ki_pos = EOF iocb->ki_pos = EOF
write(data1)
write(data2)
shared_unlock() shared_unlock()
The data2 will overlap the data1 from the same file offset, the
old EOF.
Switch to exclusive lock instead when O_APPEND is specified.
Signed-off-by: Xiubo Li <xiubli@redhat.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Diffstat (limited to 'fs/ceph/file.c')
| -rw-r--r-- | fs/ceph/file.c | 17 |
1 files changed, 11 insertions, 6 deletions
diff --git a/fs/ceph/file.c b/fs/ceph/file.c index c3b8e8e0bf17..7e0190b1f821 100644 --- a/fs/ceph/file.c +++ b/fs/ceph/file.c @@ -1418,6 +1418,7 @@ static ssize_t ceph_write_iter(struct kiocb *iocb, struct iov_iter *from) struct ceph_cap_flush *prealloc_cf; ssize_t count, written = 0; int err, want, got; + bool direct_lock = false; loff_t pos; loff_t limit = max(i_size_read(inode), fsc->max_file_size); @@ -1428,8 +1429,11 @@ static ssize_t ceph_write_iter(struct kiocb *iocb, struct iov_iter *from) if (!prealloc_cf) return -ENOMEM; + if ((iocb->ki_flags & (IOCB_DIRECT | IOCB_APPEND)) == IOCB_DIRECT) + direct_lock = true; + retry_snap: - if (iocb->ki_flags & IOCB_DIRECT) + if (direct_lock) ceph_start_io_direct(inode); else ceph_start_io_write(inode); @@ -1519,14 +1523,15 @@ retry_snap: /* we might need to revert back to that point */ data = *from; - if (iocb->ki_flags & IOCB_DIRECT) { + if (iocb->ki_flags & IOCB_DIRECT) written = ceph_direct_read_write(iocb, &data, snapc, &prealloc_cf); - ceph_end_io_direct(inode); - } else { + else written = ceph_sync_write(iocb, &data, pos, snapc); + if (direct_lock) + ceph_end_io_direct(inode); + else ceph_end_io_write(inode); - } if (written > 0) iov_iter_advance(from, written); ceph_put_snap_context(snapc); @@ -1577,7 +1582,7 @@ retry_snap: goto out_unlocked; out: - if (iocb->ki_flags & IOCB_DIRECT) + if (direct_lock) ceph_end_io_direct(inode); else ceph_end_io_write(inode); |