From: Darrick J. Wong <djwong@xxxxxxxxxx>
If userspace asks us to perform readahead on a file, take i_rwsem so
that it can't race with hole punching or writes.
Signed-off-by: "Darrick J. Wong" <djwong@xxxxxxxxxx>
---
fs/fuse/fuse_i.h | 3 +++
fs/fuse/file.c | 1 +
fs/fuse/file_iomap.c | 20 ++++++++++++++++++++
3 files changed, 24 insertions(+)
diff --git a/fs/fuse/fuse_i.h b/fs/fuse/fuse_i.h
index 136b9e5aabaf51..5fba84c75f4a64 100644
--- a/fs/fuse/fuse_i.h
+++ b/fs/fuse/fuse_i.h
@@ -1714,6 +1714,8 @@ int fuse_iomap_flush_unmap_range(struct inode *inode, loff_t pos,
int fuse_dev_ioctl_iomap_support(struct file *file,
struct fuse_iomap_support __user *argp);
+
+int fuse_iomap_fadvise(struct file *file, loff_t start, loff_t end, int advice);
#else
# define fuse_iomap_enabled(...) (false)
# define fuse_has_iomap(...) (false)
@@ -1742,6 +1744,7 @@ int fuse_dev_ioctl_iomap_support(struct file *file,
# define fuse_iomap_fallocate(...) (-ENOSYS)
# define fuse_iomap_flush_unmap_range(...) (-ENOSYS)
# define fuse_dev_ioctl_iomap_support(...) (-EOPNOTSUPP)
+# define fuse_iomap_fadvise NULL
#endif
#endif /* _FS_FUSE_I_H */
diff --git a/fs/fuse/file.c b/fs/fuse/file.c
index 207836e2e09cc4..78e776878427e3 100644
--- a/fs/fuse/file.c
+++ b/fs/fuse/file.c
@@ -3236,6 +3236,7 @@ static const struct file_operations fuse_file_operations = {
.poll = fuse_file_poll,
.fallocate = fuse_file_fallocate,
.copy_file_range = fuse_copy_file_range,
+ .fadvise = fuse_iomap_fadvise,
};
static const struct address_space_operations fuse_file_aops = {
diff --git a/fs/fuse/file_iomap.c b/fs/fuse/file_iomap.c
index 5253f7ef88c110..3f6e0496c4744b 100644
--- a/fs/fuse/file_iomap.c
+++ b/fs/fuse/file_iomap.c
@@ -8,6 +8,7 @@
#include <linux/iomap.h>
#include <linux/pagemap.h>
#include <linux/falloc.h>
+#include <linux/fadvise.h>
static bool __read_mostly enable_iomap =
#if IS_ENABLED(CONFIG_FUSE_IOMAP_BY_DEFAULT)
@@ -1831,3 +1832,22 @@ int fuse_dev_ioctl_iomap_support(struct file *file,
return -EFAULT;
return 0;
}
+
+int fuse_iomap_fadvise(struct file *file, loff_t start, loff_t end, int advice)
+{
+ struct inode *inode = file_inode(file);
+ bool needlock = advice == POSIX_FADV_WILLNEED &&
+ fuse_has_iomap_fileio(inode);
+ int ret;
+
+ /*
+ * Operations creating pages in page cache need protection from hole
+ * punching and similar ops
+ */
+ if (needlock)
+ inode_lock_shared(inode);
+ ret = generic_fadvise(file, start, end, advice);
+ if (needlock)
+ inode_unlock_shared(inode);
+ return ret;
+}
