1 files changed, 401 insertions, 0 deletions
diff --git a/fs/exfat/file.c b/fs/exfat/file.c
new file mode 100644
index 000000000..65f97fd2e
--- /dev/null
+++ b/fs/exfat/file.c
@@ -0,0 +1,401 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (C) 2012-2013 Samsung Electronics Co., Ltd.
+ */
+
+#include <linux/slab.h>
+#include <linux/compat.h>
+#include <linux/cred.h>
+#include <linux/buffer_head.h>
+#include <linux/blkdev.h>
+
+#include "exfat_raw.h"
+#include "exfat_fs.h"
+
+static int exfat_cont_expand(struct inode *inode, loff_t size)
+{
+	struct address_space *mapping = inode->i_mapping;
+	loff_t start = i_size_read(inode), count = size - i_size_read(inode);
+	int err, err2;
+
+	err = generic_cont_expand_simple(inode, size);
+	if (err)
+		return err;
+
+	inode->i_ctime = inode->i_mtime = current_time(inode);
+	mark_inode_dirty(inode);
+
+	if (!IS_SYNC(inode))
+		return 0;
+
+	err = filemap_fdatawrite_range(mapping, start, start + count - 1);
+	err2 = sync_mapping_buffers(mapping);
+	if (!err)
+		err = err2;
+	err2 = write_inode_now(inode, 1);
+	if (!err)
+		err = err2;
+	if (err)
+		return err;
+
+	return filemap_fdatawait_range(mapping, start, start + count - 1);
+}
+
+static bool exfat_allow_set_time(struct exfat_sb_info *sbi, struct inode *inode)
+{
+	mode_t allow_utime = sbi->options.allow_utime;
+
+	if (!uid_eq(current_fsuid(), inode->i_uid)) {
+		if (in_group_p(inode->i_gid))
+			allow_utime >>= 3;
+		if (allow_utime & MAY_WRITE)
+			return true;
+	}
+
+	/* use a default check */
+	return false;
+}
+
+static int exfat_sanitize_mode(const struct exfat_sb_info *sbi,
+		struct inode *inode, umode_t *mode_ptr)
+{
+	mode_t i_mode, mask, perm;
+
+	i_mode = inode->i_mode;
+
+	mask = (S_ISREG(i_mode) || S_ISLNK(i_mode)) ?
+		sbi->options.fs_fmask : sbi->options.fs_dmask;
+	perm = *mode_ptr & ~(S_IFMT | mask);
+
+	/* Of the r and x bits, all (subject to umask) must be present.*/
+	if ((perm & 0555) != (i_mode & 0555))
+		return -EPERM;
+
+	if (exfat_mode_can_hold_ro(inode)) {
+		/*
+		 * Of the w bits, either all (subject to umask) or none must
+		 * be present.
+		 */
+		if ((perm & 0222) && ((perm & 0222) != (0222 & ~mask)))
+			return -EPERM;
+	} else {
+		/*
+		 * If exfat_mode_can_hold_ro(inode) is false, can't change
+		 * w bits.
+		 */
+		if ((perm & 0222) != (0222 & ~mask))
+			return -EPERM;
+	}
+
+	*mode_ptr &= S_IFMT | perm;
+
+	return 0;
+}
+
+/* resize the file length */
+int __exfat_truncate(struct inode *inode, loff_t new_size)
+{
+	unsigned int num_clusters_new, num_clusters_phys;
+	unsigned int last_clu = EXFAT_FREE_CLUSTER;
+	struct exfat_chain clu;
+	struct super_block *sb = inode->i_sb;
+	struct exfat_sb_info *sbi = EXFAT_SB(sb);
+	struct exfat_inode_info *ei = EXFAT_I(inode);
+
+	/* check if the given file ID is opened */
+	if (ei->type != TYPE_FILE && ei->type != TYPE_DIR)
+		return -EPERM;
+
+	exfat_set_volume_dirty(sb);
+
+	num_clusters_new = EXFAT_B_TO_CLU_ROUND_UP(i_size_read(inode), sbi);
+	num_clusters_phys = EXFAT_B_TO_CLU_ROUND_UP(ei->i_size_ondisk, sbi);
+
+	exfat_chain_set(&clu, ei->start_clu, num_clusters_phys, ei->flags);
+
+	if (new_size > 0) {
+		/*
+		 * Truncate FAT chain num_clusters after the first cluster
+		 * num_clusters = min(new, phys);
+		 */
+		unsigned int num_clusters =
+			min(num_clusters_new, num_clusters_phys);
+
+		/*
+		 * Follow FAT chain
+		 * (defensive coding - works fine even with corrupted FAT table
+		 */
+		if (clu.flags == ALLOC_NO_FAT_CHAIN) {
+			clu.dir += num_clusters;
+			clu.size -= num_clusters;
+		} else {
+			while (num_clusters > 0) {
+				last_clu = clu.dir;
+				if (exfat_get_next_cluster(sb, &(clu.dir)))
+					return -EIO;
+
+				num_clusters--;
+				clu.size--;
+			}
+		}
+	} else {
+		ei->flags = ALLOC_NO_FAT_CHAIN;
+		ei->start_clu = EXFAT_EOF_CLUSTER;
+	}
+
+	i_size_write(inode, new_size);
+
+	if (ei->type == TYPE_FILE)
+		ei->attr |= ATTR_ARCHIVE;
+
+	/*
+	 * update the directory entry
+	 *
+	 * If the directory entry is updated by mark_inode_dirty(), the
+	 * directory entry will be written after a writeback cycle of
+	 * updating the bitmap/FAT, which may result in clusters being
+	 * freed but referenced by the directory entry in the event of a
+	 * sudden power failure.
+	 * __exfat_write_inode() is called for directory entry, bitmap
+	 * and FAT to be written in a same writeback.
+	 */
+	if (__exfat_write_inode(inode, inode_needs_sync(inode)))
+		return -EIO;
+
+	/* cut off from the FAT chain */
+	if (ei->flags == ALLOC_FAT_CHAIN && last_clu != EXFAT_FREE_CLUSTER &&
+			last_clu != EXFAT_EOF_CLUSTER) {
+		if (exfat_ent_set(sb, last_clu, EXFAT_EOF_CLUSTER))
+			return -EIO;
+	}
+
+	/* invalidate cache and free the clusters */
+	/* clear exfat cache */
+	exfat_cache_inval_inode(inode);
+
+	/* hint information */
+	ei->hint_bmap.off = EXFAT_EOF_CLUSTER;
+	ei->hint_bmap.clu = EXFAT_EOF_CLUSTER;
+
+	/* hint_stat will be used if this is directory. */
+	ei->hint_stat.eidx = 0;
+	ei->hint_stat.clu = ei->start_clu;
+	ei->hint_femp.eidx = EXFAT_HINT_NONE;
+
+	/* free the clusters */
+	if (exfat_free_cluster(inode, &clu))
+		return -EIO;
+
+	return 0;
+}
+
+void exfat_truncate(struct inode *inode, loff_t size)
+{
+	struct super_block *sb = inode->i_sb;
+	struct exfat_sb_info *sbi = EXFAT_SB(sb);
+	struct exfat_inode_info *ei = EXFAT_I(inode);
+	unsigned int blocksize = i_blocksize(inode);
+	loff_t aligned_size;
+	int err;
+
+	mutex_lock(&sbi->s_lock);
+	if (ei->start_clu == 0) {
+		/*
+		 * Empty start_clu != ~0 (not allocated)
+		 */
+		exfat_fs_error(sb, "tried to truncate zeroed cluster.");
+		goto write_size;
+	}
+
+	err = __exfat_truncate(inode, i_size_read(inode));
+	if (err)
+		goto write_size;
+
+	inode->i_blocks = round_up(i_size_read(inode), sbi->cluster_size) >> 9;
+write_size:
+	aligned_size = i_size_read(inode);
+	if (aligned_size & (blocksize - 1)) {
+		aligned_size |= (blocksize - 1);
+		aligned_size++;
+	}
+
+	if (ei->i_size_ondisk > i_size_read(inode))
+		ei->i_size_ondisk = aligned_size;
+
+	if (ei->i_size_aligned > i_size_read(inode))
+		ei->i_size_aligned = aligned_size;
+	mutex_unlock(&sbi->s_lock);
+}
+
+int exfat_getattr(struct user_namespace *mnt_uerns, const struct path *path,
+		  struct kstat *stat, unsigned int request_mask,
+		  unsigned int query_flags)
+{
+	struct inode *inode = d_backing_inode(path->dentry);
+	struct exfat_inode_info *ei = EXFAT_I(inode);
+
+	generic_fillattr(&init_user_ns, inode, stat);
+	exfat_truncate_atime(&stat->atime);
+	stat->result_mask |= STATX_BTIME;
+	stat->btime.tv_sec = ei->i_crtime.tv_sec;
+	stat->btime.tv_nsec = ei->i_crtime.tv_nsec;
+	stat->blksize = EXFAT_SB(inode->i_sb)->cluster_size;
+	return 0;
+}
+
+int exfat_setattr(struct user_namespace *mnt_userns, struct dentry *dentry,
+		  struct iattr *attr)
+{
+	struct exfat_sb_info *sbi = EXFAT_SB(dentry->d_sb);
+	struct inode *inode = dentry->d_inode;
+	unsigned int ia_valid;
+	int error;
+
+	if ((attr->ia_valid & ATTR_SIZE) &&
+	    attr->ia_size > i_size_read(inode)) {
+		error = exfat_cont_expand(inode, attr->ia_size);
+		if (error || attr->ia_valid == ATTR_SIZE)
+			return error;
+		attr->ia_valid &= ~ATTR_SIZE;
+	}
+
+	/* Check for setting the inode time. */
+	ia_valid = attr->ia_valid;
+	if ((ia_valid & (ATTR_MTIME_SET | ATTR_ATIME_SET | ATTR_TIMES_SET)) &&
+	    exfat_allow_set_time(sbi, inode)) {
+		attr->ia_valid &= ~(ATTR_MTIME_SET | ATTR_ATIME_SET |
+				ATTR_TIMES_SET);
+	}
+
+	error = setattr_prepare(&init_user_ns, dentry, attr);
+	attr->ia_valid = ia_valid;
+	if (error)
+		goto out;
+
+	if (((attr->ia_valid & ATTR_UID) &&
+	     !uid_eq(attr->ia_uid, sbi->options.fs_uid)) ||
+	    ((attr->ia_valid & ATTR_GID) &&
+	     !gid_eq(attr->ia_gid, sbi->options.fs_gid)) ||
+	    ((attr->ia_valid & ATTR_MODE) &&
+	     (attr->ia_mode & ~(S_IFREG | S_IFLNK | S_IFDIR | 0777)))) {
+		error = -EPERM;
+		goto out;
+	}
+
+	/*
+	 * We don't return -EPERM here. Yes, strange, but this is too
+	 * old behavior.
+	 */
+	if (attr->ia_valid & ATTR_MODE) {
+		if (exfat_sanitize_mode(sbi, inode, &attr->ia_mode) < 0)
+			attr->ia_valid &= ~ATTR_MODE;
+	}
+
+	if (attr->ia_valid & ATTR_SIZE)
+		inode->i_mtime = inode->i_ctime = current_time(inode);
+
+	setattr_copy(&init_user_ns, inode, attr);
+	exfat_truncate_atime(&inode->i_atime);
+
+	if (attr->ia_valid & ATTR_SIZE) {
+		error = exfat_block_truncate_page(inode, attr->ia_size);
+		if (error)
+			goto out;
+
+		down_write(&EXFAT_I(inode)->truncate_lock);
+		truncate_setsize(inode, attr->ia_size);
+
+		/*
+		 * __exfat_write_inode() is called from exfat_truncate(), inode
+		 * is already written by it, so mark_inode_dirty() is unneeded.
+		 */
+		exfat_truncate(inode, attr->ia_size);
+		up_write(&EXFAT_I(inode)->truncate_lock);
+	} else
+		mark_inode_dirty(inode);
+
+out:
+	return error;
+}
+
+static int exfat_ioctl_fitrim(struct inode *inode, unsigned long arg)
+{
+	struct fstrim_range range;
+	int ret = 0;
+
+	if (!capable(CAP_SYS_ADMIN))
+		return -EPERM;
+
+	if (!bdev_max_discard_sectors(inode->i_sb->s_bdev))
+		return -EOPNOTSUPP;
+
+	if (copy_from_user(&range, (struct fstrim_range __user *)arg, sizeof(range)))
+		return -EFAULT;
+
+	range.minlen = max_t(unsigned int, range.minlen,
+				bdev_discard_granularity(inode->i_sb->s_bdev));
+
+	ret = exfat_trim_fs(inode, &range);
+	if (ret < 0)
+		return ret;
+
+	if (copy_to_user((struct fstrim_range __user *)arg, &range, sizeof(range)))
+		return -EFAULT;
+
+	return 0;
+}
+
+long exfat_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
+{
+	struct inode *inode = file_inode(filp);
+
+	switch (cmd) {
+	case FITRIM:
+		return exfat_ioctl_fitrim(inode, arg);
+	default:
+		return -ENOTTY;
+	}
+}
+
+#ifdef CONFIG_COMPAT
+long exfat_compat_ioctl(struct file *filp, unsigned int cmd,
+				unsigned long arg)
+{
+	return exfat_ioctl(filp, cmd, (unsigned long)compat_ptr(arg));
+}
+#endif
+
+int exfat_file_fsync(struct file *filp, loff_t start, loff_t end, int datasync)
+{
+	struct inode *inode = filp->f_mapping->host;
+	int err;
+
+	err = __generic_file_fsync(filp, start, end, datasync);
+	if (err)
+		return err;
+
+	err = sync_blockdev(inode->i_sb->s_bdev);
+	if (err)
+		return err;
+
+	return blkdev_issue_flush(inode->i_sb->s_bdev);
+}
+
+const struct file_operations exfat_file_operations = {
+	.llseek		= generic_file_llseek,
+	.read_iter	= generic_file_read_iter,
+	.write_iter	= generic_file_write_iter,
+	.unlocked_ioctl = exfat_ioctl,
+#ifdef CONFIG_COMPAT
+	.compat_ioctl = exfat_compat_ioctl,
+#endif
+	.mmap		= generic_file_mmap,
+	.fsync		= exfat_file_fsync,
+	.splice_read	= generic_file_splice_read,
+	.splice_write	= iter_file_splice_write,
+};
+
+const struct inode_operations exfat_file_inode_operations = {
+	.setattr     = exfat_setattr,
+	.getattr     = exfat_getattr,
+};