From: Bernd Schubert <bschubert@xxxxxxx>
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@xxxxxxx>
---
fs/fuse/file.c | 64 +++++++++++++++++++++++++++++++++++---------------
1 file changed, 45 insertions(+), 19 deletions(-)
diff --git a/fs/fuse/file.c b/fs/fuse/file.c
index 243f469cac07..a64ee1392c77 100644
--- a/fs/fuse/file.c
+++ b/fs/fuse/file.c
@@ -1299,6 +1299,45 @@ 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 opf page access and direct-io difficult, shared
+ * locks actually introduce a conflict.
+ */
+ if (get_fuse_conn(inode)->direct_io_allow_mmap)
+ return true;
+
+ /* parallel dio beyond eof is at least for now not supported */
+ 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;
@@ -1558,26 +1597,12 @@ 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
@@ -1591,10 +1616,10 @@ 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;
@@ -2468,7 +2493,8 @@ static int fuse_file_mmap(struct file *file, struct vm_area_struct *vma)
return fuse_dax_mmap(file, vma);
if (ff->open_flags & FOPEN_DIRECT_IO) {
- /* Can't provide the coherency needed for MAP_SHARED
+ /*
+ * Can't provide the coherency needed for MAP_SHARED
* if FUSE_DIRECT_IO_ALLOW_MMAP isn't set.
*/
if ((vma->vm_flags & VM_MAYSHARE) && !fc->direct_io_allow_mmap)
--
2.34.1
