There is a confusion with fuse_file_uncached_io_{start,end} interface.
These helpers do two things when called from passthrough open()/release():
1. Take/drop negative refcount of fi->iocachectr (inode uncached io mode)
2. State change ff->iomode IOM_NONE <-> IOM_UNCACHED (file uncached open)
The calls from parallel dio write path need to take a reference on
fi->iocachectr, but they should not be changing ff->iomode state,
because in this case, the fi->iocachectr reference does not stick around
until file release().
Factor out helpers fuse_inode_uncached_io_{start,end}, to be used from
parallel dio write path and rename fuse_file_*cached_io_{start,end}
helpers to fuse_file_*cached_io_{open,release} to clarify the difference.
Add a check of ff->iomode in mmap(), so that fuse_file_cached_io_open()
is called only on first mmap of direct_io file.
Fixes: 205c1d802683 ("fuse: allow parallel dio writes with FUSE_DIRECT_IO_ALLOW_MMAP")
Signed-off-by: Amir Goldstein <amir73il@xxxxxxxxx>
---
fs/fuse/file.c | 18 +++++++++------
fs/fuse/fuse_i.h | 7 +++---
fs/fuse/inode.c | 1 +
fs/fuse/iomode.c | 59 ++++++++++++++++++++++++++++++++----------------
4 files changed, 56 insertions(+), 29 deletions(-)
diff --git a/fs/fuse/file.c b/fs/fuse/file.c
index a56e7bffd000..fcf20b304093 100644
--- a/fs/fuse/file.c
+++ b/fs/fuse/file.c
@@ -1362,7 +1362,7 @@ static void fuse_dio_lock(struct kiocb *iocb, struct iov_iter *from,
bool *exclusive)
{
struct inode *inode = file_inode(iocb->ki_filp);
- struct fuse_file *ff = iocb->ki_filp->private_data;
+ struct fuse_inode *fi = get_fuse_inode(inode);
*exclusive = fuse_dio_wr_exclusive_lock(iocb, from);
if (*exclusive) {
@@ -1377,7 +1377,7 @@ static void fuse_dio_lock(struct kiocb *iocb, struct iov_iter *from,
* have raced, so check it again.
*/
if (fuse_io_past_eof(iocb, from) ||
- fuse_file_uncached_io_start(inode, ff, NULL) != 0) {
+ fuse_inode_uncached_io_start(fi, NULL) != 0) {
inode_unlock_shared(inode);
inode_lock(inode);
*exclusive = true;
@@ -1388,13 +1388,13 @@ static void fuse_dio_lock(struct kiocb *iocb, struct iov_iter *from,
static void fuse_dio_unlock(struct kiocb *iocb, bool exclusive)
{
struct inode *inode = file_inode(iocb->ki_filp);
- struct fuse_file *ff = iocb->ki_filp->private_data;
+ struct fuse_inode *fi = get_fuse_inode(inode);
if (exclusive) {
inode_unlock(inode);
} else {
/* Allow opens in caching mode after last parallel dio end */
- fuse_file_uncached_io_end(inode, ff);
+ fuse_inode_uncached_io_end(fi);
inode_unlock_shared(inode);
}
}
@@ -2574,10 +2574,14 @@ static int fuse_file_mmap(struct file *file, struct vm_area_struct *vma)
* First mmap of direct_io file enters caching inode io mode.
* Also waits for parallel dio writers to go into serial mode
* (exclusive instead of shared lock).
+ * After first mmap, the inode stays in caching io mode until
+ * the direct_io file release.
*/
- rc = fuse_file_cached_io_start(inode, ff);
- if (rc)
- return rc;
+ if (READ_ONCE(ff->iomode) != IOM_CACHED) {
+ rc = fuse_file_cached_io_open(inode, ff);
+ if (rc)
+ return rc;
+ }
}
if ((vma->vm_flags & VM_SHARED) && (vma->vm_flags & VM_MAYWRITE))
diff --git a/fs/fuse/fuse_i.h b/fs/fuse/fuse_i.h
index b24084b60864..f23919610313 100644
--- a/fs/fuse/fuse_i.h
+++ b/fs/fuse/fuse_i.h
@@ -1394,9 +1394,10 @@ int fuse_fileattr_set(struct mnt_idmap *idmap,
struct dentry *dentry, struct fileattr *fa);
/* iomode.c */
-int fuse_file_cached_io_start(struct inode *inode, struct fuse_file *ff);
-int fuse_file_uncached_io_start(struct inode *inode, struct fuse_file *ff, struct fuse_backing *fb);
-void fuse_file_uncached_io_end(struct inode *inode, struct fuse_file *ff);
+int fuse_file_cached_io_open(struct inode *inode, struct fuse_file *ff);
+int fuse_inode_uncached_io_start(struct fuse_inode *fi,
+ struct fuse_backing *fb);
+void fuse_inode_uncached_io_end(struct fuse_inode *fi);
int fuse_file_io_open(struct file *file, struct inode *inode);
void fuse_file_io_release(struct fuse_file *ff, struct inode *inode);
diff --git a/fs/fuse/inode.c b/fs/fuse/inode.c
index 3a5d88878335..99e44ea7d875 100644
--- a/fs/fuse/inode.c
+++ b/fs/fuse/inode.c
@@ -175,6 +175,7 @@ static void fuse_evict_inode(struct inode *inode)
}
}
if (S_ISREG(inode->i_mode) && !fuse_is_bad(inode)) {
+ WARN_ON(fi->iocachectr != 0);
WARN_ON(!list_empty(&fi->write_files));
WARN_ON(!list_empty(&fi->queued_writes));
}
diff --git a/fs/fuse/iomode.c b/fs/fuse/iomode.c
index c653ddcf0578..1519f895f0a9 100644
--- a/fs/fuse/iomode.c
+++ b/fs/fuse/iomode.c
@@ -21,12 +21,13 @@ static inline bool fuse_is_io_cache_wait(struct fuse_inode *fi)
}
/*
- * Start cached io mode.
+ * Called on cached file open() and on first mmap() of direct_io file.
+ * Takes cached_io inode mode reference to be dropped on file release.
*
* Blocks new parallel dio writes and waits for the in-progress parallel dio
* writes to complete.
*/
-int fuse_file_cached_io_start(struct inode *inode, struct fuse_file *ff)
+int fuse_file_cached_io_open(struct inode *inode, struct fuse_file *ff)
{
struct fuse_inode *fi = get_fuse_inode(inode);
@@ -56,8 +57,7 @@ int fuse_file_cached_io_start(struct inode *inode, struct fuse_file *ff)
return -ETXTBSY;
}
- WARN_ON(ff->iomode == IOM_UNCACHED);
- if (ff->iomode == IOM_NONE) {
+ if (!WARN_ON(ff->iomode != IOM_NONE)) {
ff->iomode = IOM_CACHED;
if (fi->iocachectr == 0)
set_bit(FUSE_I_CACHE_IO_MODE, &fi->state);
@@ -67,10 +67,9 @@ int fuse_file_cached_io_start(struct inode *inode, struct fuse_file *ff)
return 0;
}
-static void fuse_file_cached_io_end(struct inode *inode, struct fuse_file *ff)
+static void fuse_file_cached_io_release(struct fuse_file *ff,
+ struct fuse_inode *fi)
{
- struct fuse_inode *fi = get_fuse_inode(inode);
-
spin_lock(&fi->lock);
WARN_ON(fi->iocachectr <= 0);
WARN_ON(ff->iomode != IOM_CACHED);
@@ -82,9 +81,8 @@ static void fuse_file_cached_io_end(struct inode *inode, struct fuse_file *ff)
}
/* Start strictly uncached io mode where cache access is not allowed */
-int fuse_file_uncached_io_start(struct inode *inode, struct fuse_file *ff, struct fuse_backing *fb)
+int fuse_inode_uncached_io_start(struct fuse_inode *fi, struct fuse_backing *fb)
{
- struct fuse_inode *fi = get_fuse_inode(inode);
struct fuse_backing *oldfb;
int err = 0;
@@ -99,9 +97,7 @@ int fuse_file_uncached_io_start(struct inode *inode, struct fuse_file *ff, struc
err = -ETXTBSY;
goto unlock;
}
- WARN_ON(ff->iomode != IOM_NONE);
fi->iocachectr--;
- ff->iomode = IOM_UNCACHED;
/* fuse inode holds a single refcount of backing file */
if (!oldfb) {
@@ -115,15 +111,29 @@ int fuse_file_uncached_io_start(struct inode *inode, struct fuse_file *ff, struc
return err;
}
-void fuse_file_uncached_io_end(struct inode *inode, struct fuse_file *ff)
+/* Takes uncached_io inode mode reference to be dropped on file release */
+static int fuse_file_uncached_io_open(struct inode *inode,
+ struct fuse_file *ff,
+ struct fuse_backing *fb)
{
struct fuse_inode *fi = get_fuse_inode(inode);
+ int err;
+
+ err = fuse_inode_uncached_io_start(fi, fb);
+ if (err)
+ return err;
+
+ WARN_ON(ff->iomode != IOM_NONE);
+ ff->iomode = IOM_UNCACHED;
+ return 0;
+}
+
+void fuse_inode_uncached_io_end(struct fuse_inode *fi)
+{
struct fuse_backing *oldfb = NULL;
spin_lock(&fi->lock);
WARN_ON(fi->iocachectr >= 0);
- WARN_ON(ff->iomode != IOM_UNCACHED);
- ff->iomode = IOM_NONE;
fi->iocachectr++;
if (!fi->iocachectr) {
wake_up(&fi->direct_io_waitq);
@@ -134,6 +144,15 @@ void fuse_file_uncached_io_end(struct inode *inode, struct fuse_file *ff)
fuse_backing_put(oldfb);
}
+/* Drop uncached_io reference from passthrough open */
+static void fuse_file_uncached_io_release(struct fuse_file *ff,
+ struct fuse_inode *fi)
+{
+ WARN_ON(ff->iomode != IOM_UNCACHED);
+ ff->iomode = IOM_NONE;
+ fuse_inode_uncached_io_end(fi);
+}
+
/*
* Open flags that are allowed in combination with FOPEN_PASSTHROUGH.
* A combination of FOPEN_PASSTHROUGH and FOPEN_DIRECT_IO means that read/write
@@ -163,7 +182,7 @@ static int fuse_file_passthrough_open(struct inode *inode, struct file *file)
return PTR_ERR(fb);
/* First passthrough file open denies caching inode io mode */
- err = fuse_file_uncached_io_start(inode, ff, fb);
+ err = fuse_file_uncached_io_open(inode, ff, fb);
if (!err)
return 0;
@@ -216,7 +235,7 @@ int fuse_file_io_open(struct file *file, struct inode *inode)
if (ff->open_flags & FOPEN_PASSTHROUGH)
err = fuse_file_passthrough_open(inode, file);
else
- err = fuse_file_cached_io_start(inode, ff);
+ err = fuse_file_cached_io_open(inode, ff);
if (err)
goto fail;
@@ -236,8 +255,10 @@ int fuse_file_io_open(struct file *file, struct inode *inode)
/* No more pending io and no new io possible to inode via open/mmapped file */
void fuse_file_io_release(struct fuse_file *ff, struct inode *inode)
{
+ struct fuse_inode *fi = get_fuse_inode(inode);
+
/*
- * Last parallel dio close allows caching inode io mode.
+ * Last passthrough file close allows caching inode io mode.
* Last caching file close exits caching inode io mode.
*/
switch (ff->iomode) {
@@ -245,10 +266,10 @@ void fuse_file_io_release(struct fuse_file *ff, struct inode *inode)
/* Nothing to do */
break;
case IOM_UNCACHED:
- fuse_file_uncached_io_end(inode, ff);
+ fuse_file_uncached_io_release(ff, fi);
break;
case IOM_CACHED:
- fuse_file_cached_io_end(inode, ff);
+ fuse_file_cached_io_release(ff, fi);
break;
}
}
--
2.34.1
