Add NFS export support to the exFAT filesystem by implementing
the necessary export operations in fs/exfat/super.c. Enable
exFAT filesystems to be exported and accessed over NFS, enhancing
their utility in networked environments.
Introduce the exfat_export_ops structure, which includes
functions to handle file handles and inode lookups necessary for NFS
operations.
Signed-off-by: Sergii Boryshchenko <sergii.boryshchenko@xxxxxxxxxxxxxxx>
Signed-off-by: Andrii Polianytsia <andrii.polianytsia@xxxxxxxxxxxxxxx>
---
fs/exfat/super.c | 65 ++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 65 insertions(+)
diff --git a/fs/exfat/super.c b/fs/exfat/super.c
index 323ecebe6f0e..cb6dcafc3007 100644
--- a/fs/exfat/super.c
+++ b/fs/exfat/super.c
@@ -18,6 +18,7 @@
#include <linux/nls.h>
#include <linux/buffer_head.h>
#include <linux/magic.h>
+#include <linux/exportfs.h>
#include "exfat_raw.h"
#include "exfat_fs.h"
@@ -195,6 +196,69 @@ static const struct super_operations exfat_sops = {
.show_options = exfat_show_options,
};
+/**
+ * exfat_export_get_inode - Get inode for export operations
+ * @sb: Superblock pointer
+ * @ino: Inode number
+ * @generation: Generation number
+ *
+ * Returns pointer to inode or error pointer in case of an error.
+ */
+static struct inode *exfat_export_get_inode(struct super_block *sb, u64 ino,
+ u32 generation)
+{
+ struct inode *inode = NULL;
+
+ if (ino == 0)
+ return ERR_PTR(-ESTALE);
+
+ inode = ilookup(sb, ino);
+ if (inode && generation && inode->i_generation != generation) {
+ iput(inode);
+ return ERR_PTR(-ESTALE);
+ }
+
+ return inode;
+}
+
+/**
+ * exfat_fh_to_dentry - Convert file handle to dentry
+ * @sb: Superblock pointer
+ * @fid: File identifier
+ * @fh_len: Length of the file handle
+ * @fh_type: Type of the file handle
+ *
+ * Returns dentry corresponding to the file handle.
+ */
+static struct dentry *exfat_fh_to_dentry(struct super_block *sb,
+ struct fid *fid, int fh_len, int fh_type)
+{
+ return generic_fh_to_dentry(sb, fid, fh_len, fh_type,
+ exfat_export_get_inode);
+}
+
+/**
+ * exfat_fh_to_parent - Convert file handle to parent dentry
+ * @sb: Superblock pointer
+ * @fid: File identifier
+ * @fh_len: Length of the file handle
+ * @fh_type: Type of the file handle
+ *
+ * Returns parent dentry corresponding to the file handle.
+ */
+static struct dentry *exfat_fh_to_parent(struct super_block *sb,
+ struct fid *fid, int fh_len, int fh_type)
+{
+ return generic_fh_to_parent(sb, fid, fh_len, fh_type,
+ exfat_export_get_inode);
+}
+
+static const struct export_operations exfat_export_ops = {
+ .encode_fh = generic_encode_ino32_fh,
+ .fh_to_dentry = exfat_fh_to_dentry,
+ .fh_to_parent = exfat_fh_to_parent,
+};
+
enum {
Opt_uid,
Opt_gid,
@@ -633,6 +697,7 @@ static int exfat_fill_super(struct super_block *sb, struct fs_context *fc)
sb->s_flags |= SB_NODIRATIME;
sb->s_magic = EXFAT_SUPER_MAGIC;
sb->s_op = &exfat_sops;
+ sb->s_export_op = &exfat_export_ops;
sb->s_time_gran = 10 * NSEC_PER_MSEC;
sb->s_time_min = EXFAT_MIN_TIMESTAMP_SECS;
--
2.25.1
