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-rw-r--r--fs/fuse/dax.c49
-rw-r--r--fs/fuse/dir.c32
-rw-r--r--fs/fuse/file.c30
-rw-r--r--fs/fuse/fuse_i.h8
-rw-r--r--fs/fuse/inode.c1
5 files changed, 110 insertions, 10 deletions
diff --git a/fs/fuse/dax.c b/fs/fuse/dax.c
index c21305409191..efc1a8ef5639 100644
--- a/fs/fuse/dax.c
+++ b/fs/fuse/dax.c
@@ -495,6 +495,47 @@ static const struct iomap_ops fuse_iomap_ops = {
.iomap_end = fuse_iomap_end,
};
+static void fuse_wait_dax_page(struct inode *inode)
+{
+ struct fuse_inode *fi = get_fuse_inode(inode);
+
+ up_write(&fi->i_mmap_sem);
+ schedule();
+ down_write(&fi->i_mmap_sem);
+}
+
+/* Should be called with fi->i_mmap_sem lock held exclusively */
+static int __fuse_dax_break_layouts(struct inode *inode, bool *retry,
+ loff_t start, loff_t end)
+{
+ struct page *page;
+
+ page = dax_layout_busy_page_range(inode->i_mapping, start, end);
+ if (!page)
+ return 0;
+
+ *retry = true;
+ return ___wait_var_event(&page->_refcount,
+ atomic_read(&page->_refcount) == 1, TASK_INTERRUPTIBLE,
+ 0, 0, fuse_wait_dax_page(inode));
+}
+
+/* dmap_end == 0 leads to unmapping of whole file */
+int fuse_dax_break_layouts(struct inode *inode, u64 dmap_start,
+ u64 dmap_end)
+{
+ bool retry;
+ int ret;
+
+ do {
+ retry = false;
+ ret = __fuse_dax_break_layouts(inode, &retry, dmap_start,
+ dmap_end);
+ } while (ret == 0 && retry);
+
+ return ret;
+}
+
ssize_t fuse_dax_read_iter(struct kiocb *iocb, struct iov_iter *to)
{
struct inode *inode = file_inode(iocb->ki_filp);
@@ -596,10 +637,18 @@ static vm_fault_t __fuse_dax_fault(struct vm_fault *vmf,
if (write)
sb_start_pagefault(sb);
+ /*
+ * We need to serialize against not only truncate but also against
+ * fuse dax memory range reclaim. While a range is being reclaimed,
+ * we do not want any read/write/mmap to make progress and try
+ * to populate page cache or access memory we are trying to free.
+ */
+ down_read(&get_fuse_inode(inode)->i_mmap_sem);
ret = dax_iomap_fault(vmf, pe_size, &pfn, NULL, &fuse_iomap_ops);
if (ret & VM_FAULT_NEEDDSYNC)
ret = dax_finish_sync_fault(vmf, pe_size, pfn);
+ up_read(&get_fuse_inode(inode)->i_mmap_sem);
if (write)
sb_end_pagefault(sb);
diff --git a/fs/fuse/dir.c b/fs/fuse/dir.c
index 26f028bc760b..c4a01290aec6 100644
--- a/fs/fuse/dir.c
+++ b/fs/fuse/dir.c
@@ -1501,6 +1501,7 @@ int fuse_do_setattr(struct dentry *dentry, struct iattr *attr,
loff_t oldsize;
int err;
bool trust_local_cmtime = is_wb && S_ISREG(inode->i_mode);
+ bool fault_blocked = false;
if (!fc->default_permissions)
attr->ia_valid |= ATTR_FORCE;
@@ -1509,6 +1510,22 @@ int fuse_do_setattr(struct dentry *dentry, struct iattr *attr,
if (err)
return err;
+ if (attr->ia_valid & ATTR_SIZE) {
+ if (WARN_ON(!S_ISREG(inode->i_mode)))
+ return -EIO;
+ is_truncate = true;
+ }
+
+ if (FUSE_IS_DAX(inode) && is_truncate) {
+ down_write(&fi->i_mmap_sem);
+ fault_blocked = true;
+ err = fuse_dax_break_layouts(inode, 0, 0);
+ if (err) {
+ up_write(&fi->i_mmap_sem);
+ return err;
+ }
+ }
+
if (attr->ia_valid & ATTR_OPEN) {
/* This is coming from open(..., ... | O_TRUNC); */
WARN_ON(!(attr->ia_valid & ATTR_SIZE));
@@ -1521,17 +1538,11 @@ int fuse_do_setattr(struct dentry *dentry, struct iattr *attr,
*/
i_size_write(inode, 0);
truncate_pagecache(inode, 0);
- return 0;
+ goto out;
}
file = NULL;
}
- if (attr->ia_valid & ATTR_SIZE) {
- if (WARN_ON(!S_ISREG(inode->i_mode)))
- return -EIO;
- is_truncate = true;
- }
-
/* Flush dirty data/metadata before non-truncate SETATTR */
if (is_wb && S_ISREG(inode->i_mode) &&
attr->ia_valid &
@@ -1614,6 +1625,10 @@ int fuse_do_setattr(struct dentry *dentry, struct iattr *attr,
}
clear_bit(FUSE_I_SIZE_UNSTABLE, &fi->state);
+out:
+ if (fault_blocked)
+ up_write(&fi->i_mmap_sem);
+
return 0;
error:
@@ -1621,6 +1636,9 @@ error:
fuse_release_nowrite(inode);
clear_bit(FUSE_I_SIZE_UNSTABLE, &fi->state);
+
+ if (fault_blocked)
+ up_write(&fi->i_mmap_sem);
return err;
}
diff --git a/fs/fuse/file.c b/fs/fuse/file.c
index 2aac787464bc..172a0b1aa634 100644
--- a/fs/fuse/file.c
+++ b/fs/fuse/file.c
@@ -221,22 +221,34 @@ int fuse_open_common(struct inode *inode, struct file *file, bool isdir)
bool is_wb_truncate = (file->f_flags & O_TRUNC) &&
fc->atomic_o_trunc &&
fc->writeback_cache;
+ bool dax_truncate = (file->f_flags & O_TRUNC) &&
+ fc->atomic_o_trunc && FUSE_IS_DAX(inode);
err = generic_file_open(inode, file);
if (err)
return err;
- if (is_wb_truncate) {
+ if (is_wb_truncate || dax_truncate) {
inode_lock(inode);
fuse_set_nowrite(inode);
}
- err = fuse_do_open(fc, get_node_id(inode), file, isdir);
+ if (dax_truncate) {
+ down_write(&get_fuse_inode(inode)->i_mmap_sem);
+ err = fuse_dax_break_layouts(inode, 0, 0);
+ if (err)
+ goto out;
+ }
+ err = fuse_do_open(fc, get_node_id(inode), file, isdir);
if (!err)
fuse_finish_open(inode, file);
- if (is_wb_truncate) {
+out:
+ if (dax_truncate)
+ up_write(&get_fuse_inode(inode)->i_mmap_sem);
+
+ if (is_wb_truncate | dax_truncate) {
fuse_release_nowrite(inode);
inode_unlock(inode);
}
@@ -3221,6 +3233,8 @@ static long fuse_file_fallocate(struct file *file, int mode, loff_t offset,
bool lock_inode = !(mode & FALLOC_FL_KEEP_SIZE) ||
(mode & FALLOC_FL_PUNCH_HOLE);
+ bool block_faults = FUSE_IS_DAX(inode) && lock_inode;
+
if (mode & ~(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE))
return -EOPNOTSUPP;
@@ -3229,6 +3243,13 @@ static long fuse_file_fallocate(struct file *file, int mode, loff_t offset,
if (lock_inode) {
inode_lock(inode);
+ if (block_faults) {
+ down_write(&fi->i_mmap_sem);
+ err = fuse_dax_break_layouts(inode, 0, 0);
+ if (err)
+ goto out;
+ }
+
if (mode & FALLOC_FL_PUNCH_HOLE) {
loff_t endbyte = offset + length - 1;
@@ -3278,6 +3299,9 @@ out:
if (!(mode & FALLOC_FL_KEEP_SIZE))
clear_bit(FUSE_I_SIZE_UNSTABLE, &fi->state);
+ if (block_faults)
+ up_write(&fi->i_mmap_sem);
+
if (lock_inode)
inode_unlock(inode);
diff --git a/fs/fuse/fuse_i.h b/fs/fuse/fuse_i.h
index 2d2bdd596194..32c935f1e1b0 100644
--- a/fs/fuse/fuse_i.h
+++ b/fs/fuse/fuse_i.h
@@ -149,6 +149,13 @@ struct fuse_inode {
/** Lock to protect write related fields */
spinlock_t lock;
+ /**
+ * Can't take inode lock in fault path (leads to circular dependency).
+ * Introduce another semaphore which can be taken in fault path and
+ * then other filesystem paths can take this to block faults.
+ */
+ struct rw_semaphore i_mmap_sem;
+
#ifdef CONFIG_FUSE_DAX
/*
* Dax specific inode data
@@ -1116,6 +1123,7 @@ void fuse_free_conn(struct fuse_conn *fc);
ssize_t fuse_dax_read_iter(struct kiocb *iocb, struct iov_iter *to);
ssize_t fuse_dax_write_iter(struct kiocb *iocb, struct iov_iter *from);
int fuse_dax_mmap(struct file *file, struct vm_area_struct *vma);
+int fuse_dax_break_layouts(struct inode *inode, u64 dmap_start, u64 dmap_end);
int fuse_dax_conn_alloc(struct fuse_conn *fc, struct dax_device *dax_dev);
void fuse_dax_conn_free(struct fuse_conn *fc);
bool fuse_dax_inode_alloc(struct super_block *sb, struct fuse_inode *fi);
diff --git a/fs/fuse/inode.c b/fs/fuse/inode.c
index cab4239bd78a..d252237219bf 100644
--- a/fs/fuse/inode.c
+++ b/fs/fuse/inode.c
@@ -85,6 +85,7 @@ static struct inode *fuse_alloc_inode(struct super_block *sb)
fi->orig_ino = 0;
fi->state = 0;
mutex_init(&fi->mutex);
+ init_rwsem(&fi->i_mmap_sem);
spin_lock_init(&fi->lock);
fi->forget = fuse_alloc_forget();
if (!fi->forget)
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