From: Bernd Schubert <bschubert@ddn.com> mainline inclusion from mainline-v6.9-rc1 commit 699cf8246ee4c2c524f18c2e395909d16e7fda1b category: feature bugzilla: https://gitee.com/src-openeuler/kernel/issues/IBHLU4 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i... -------------------------------- This makes the code a bit easier to read and allows to more easily add more conditions when an exclusive lock is needed. Signed-off-by: Bernd Schubert <bschubert@ddn.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com> Signed-off-by: Yifan Qiao <qiaoyifan4@huawei.com> --- fs/fuse/file.c | 63 +++++++++++++++++++++++++++++++++++--------------- 1 file changed, 45 insertions(+), 18 deletions(-) diff --git a/fs/fuse/file.c b/fs/fuse/file.c index fca2be898336..bfdfe5d2c484 100644 --- a/fs/fuse/file.c +++ b/fs/fuse/file.c @@ -1305,6 +1305,47 @@ static ssize_t fuse_perform_write(struct kiocb *iocb, struct iov_iter *ii) return res; } +static bool fuse_io_past_eof(struct kiocb *iocb, struct iov_iter *iter) +{ + struct inode *inode = file_inode(iocb->ki_filp); + + return iocb->ki_pos + iov_iter_count(iter) > i_size_read(inode); +} + +/* + * @return true if an exclusive lock for direct IO writes is needed + */ +static bool fuse_dio_wr_exclusive_lock(struct kiocb *iocb, struct iov_iter *from) +{ + struct file *file = iocb->ki_filp; + struct fuse_file *ff = file->private_data; + struct inode *inode = file_inode(iocb->ki_filp); + + /* Server side has to advise that it supports parallel dio writes. */ + if (!(ff->open_flags & FOPEN_PARALLEL_DIRECT_WRITES)) + return true; + + /* + * Append will need to know the eventual EOF - always needs an + * exclusive lock. + */ + if (iocb->ki_flags & IOCB_APPEND) + return true; + + /* + * Combination of page access and direct-io is difficult, shared locks + * actually introduce a conflict. + */ + if (get_fuse_conn(inode)->direct_io_allow_mmap) + return true; + + /* Parallel dio beyond EOF is not supported, at least for now. */ + if (fuse_io_past_eof(iocb, from)) + return true; + + return false; +} + static ssize_t fuse_cache_write_iter(struct kiocb *iocb, struct iov_iter *from) { struct file *file = iocb->ki_filp; @@ -1581,26 +1622,12 @@ static ssize_t fuse_direct_read_iter(struct kiocb *iocb, struct iov_iter *to) return res; } -static bool fuse_direct_write_extending_i_size(struct kiocb *iocb, - struct iov_iter *iter) -{ - struct inode *inode = file_inode(iocb->ki_filp); - - return iocb->ki_pos + iov_iter_count(iter) > i_size_read(inode); -} - static ssize_t fuse_direct_write_iter(struct kiocb *iocb, struct iov_iter *from) { struct inode *inode = file_inode(iocb->ki_filp); - struct file *file = iocb->ki_filp; - struct fuse_file *ff = file->private_data; struct fuse_io_priv io = FUSE_IO_PRIV_SYNC(iocb); ssize_t res; - bool exclusive_lock = - !(ff->open_flags & FOPEN_PARALLEL_DIRECT_WRITES) || - get_fuse_conn(inode)->direct_io_allow_mmap || - iocb->ki_flags & IOCB_APPEND || - fuse_direct_write_extending_i_size(iocb, from); + bool exclusive_lock = fuse_dio_wr_exclusive_lock(iocb, from); /* * Take exclusive lock if @@ -1614,10 +1641,10 @@ static ssize_t fuse_direct_write_iter(struct kiocb *iocb, struct iov_iter *from) else { inode_lock_shared(inode); - /* A race with truncate might have come up as the decision for - * the lock type was done without holding the lock, check again. + /* + * Previous check was without any lock and might have raced. */ - if (fuse_direct_write_extending_i_size(iocb, from)) { + if (fuse_io_past_eof(iocb, from)) { inode_unlock_shared(inode); inode_lock(inode); exclusive_lock = true; -- 2.39.2