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-rw-r--r--fs/fat/file.c578
1 files changed, 578 insertions, 0 deletions
diff --git a/fs/fat/file.c b/fs/fat/file.c
new file mode 100644
index 0000000000..e887e9ab74
--- /dev/null
+++ b/fs/fat/file.c
@@ -0,0 +1,578 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * linux/fs/fat/file.c
+ *
+ * Written 1992,1993 by Werner Almesberger
+ *
+ * regular file handling primitives for fat-based filesystems
+ */
+
+#include <linux/capability.h>
+#include <linux/module.h>
+#include <linux/compat.h>
+#include <linux/mount.h>
+#include <linux/blkdev.h>
+#include <linux/backing-dev.h>
+#include <linux/fsnotify.h>
+#include <linux/security.h>
+#include <linux/falloc.h>
+#include "fat.h"
+
+static long fat_fallocate(struct file *file, int mode,
+ loff_t offset, loff_t len);
+
+static int fat_ioctl_get_attributes(struct inode *inode, u32 __user *user_attr)
+{
+ u32 attr;
+
+ inode_lock_shared(inode);
+ attr = fat_make_attrs(inode);
+ inode_unlock_shared(inode);
+
+ return put_user(attr, user_attr);
+}
+
+static int fat_ioctl_set_attributes(struct file *file, u32 __user *user_attr)
+{
+ struct inode *inode = file_inode(file);
+ struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
+ int is_dir = S_ISDIR(inode->i_mode);
+ u32 attr, oldattr;
+ struct iattr ia;
+ int err;
+
+ err = get_user(attr, user_attr);
+ if (err)
+ goto out;
+
+ err = mnt_want_write_file(file);
+ if (err)
+ goto out;
+ inode_lock(inode);
+
+ /*
+ * ATTR_VOLUME and ATTR_DIR cannot be changed; this also
+ * prevents the user from turning us into a VFAT
+ * longname entry. Also, we obviously can't set
+ * any of the NTFS attributes in the high 24 bits.
+ */
+ attr &= 0xff & ~(ATTR_VOLUME | ATTR_DIR);
+ /* Merge in ATTR_VOLUME and ATTR_DIR */
+ attr |= (MSDOS_I(inode)->i_attrs & ATTR_VOLUME) |
+ (is_dir ? ATTR_DIR : 0);
+ oldattr = fat_make_attrs(inode);
+
+ /* Equivalent to a chmod() */
+ ia.ia_valid = ATTR_MODE | ATTR_CTIME;
+ ia.ia_ctime = current_time(inode);
+ if (is_dir)
+ ia.ia_mode = fat_make_mode(sbi, attr, S_IRWXUGO);
+ else {
+ ia.ia_mode = fat_make_mode(sbi, attr,
+ S_IRUGO | S_IWUGO | (inode->i_mode & S_IXUGO));
+ }
+
+ /* The root directory has no attributes */
+ if (inode->i_ino == MSDOS_ROOT_INO && attr != ATTR_DIR) {
+ err = -EINVAL;
+ goto out_unlock_inode;
+ }
+
+ if (sbi->options.sys_immutable &&
+ ((attr | oldattr) & ATTR_SYS) &&
+ !capable(CAP_LINUX_IMMUTABLE)) {
+ err = -EPERM;
+ goto out_unlock_inode;
+ }
+
+ /*
+ * The security check is questionable... We single
+ * out the RO attribute for checking by the security
+ * module, just because it maps to a file mode.
+ */
+ err = security_inode_setattr(file_mnt_idmap(file),
+ file->f_path.dentry, &ia);
+ if (err)
+ goto out_unlock_inode;
+
+ /* This MUST be done before doing anything irreversible... */
+ err = fat_setattr(file_mnt_idmap(file), file->f_path.dentry, &ia);
+ if (err)
+ goto out_unlock_inode;
+
+ fsnotify_change(file->f_path.dentry, ia.ia_valid);
+ if (sbi->options.sys_immutable) {
+ if (attr & ATTR_SYS)
+ inode->i_flags |= S_IMMUTABLE;
+ else
+ inode->i_flags &= ~S_IMMUTABLE;
+ }
+
+ fat_save_attrs(inode, attr);
+ mark_inode_dirty(inode);
+out_unlock_inode:
+ inode_unlock(inode);
+ mnt_drop_write_file(file);
+out:
+ return err;
+}
+
+static int fat_ioctl_get_volume_id(struct inode *inode, u32 __user *user_attr)
+{
+ struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
+ return put_user(sbi->vol_id, user_attr);
+}
+
+static int fat_ioctl_fitrim(struct inode *inode, unsigned long arg)
+{
+ struct super_block *sb = inode->i_sb;
+ struct fstrim_range __user *user_range;
+ struct fstrim_range range;
+ int err;
+
+ if (!capable(CAP_SYS_ADMIN))
+ return -EPERM;
+
+ if (!bdev_max_discard_sectors(sb->s_bdev))
+ return -EOPNOTSUPP;
+
+ user_range = (struct fstrim_range __user *)arg;
+ if (copy_from_user(&range, user_range, sizeof(range)))
+ return -EFAULT;
+
+ range.minlen = max_t(unsigned int, range.minlen,
+ bdev_discard_granularity(sb->s_bdev));
+
+ err = fat_trim_fs(inode, &range);
+ if (err < 0)
+ return err;
+
+ if (copy_to_user(user_range, &range, sizeof(range)))
+ return -EFAULT;
+
+ return 0;
+}
+
+long fat_generic_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
+{
+ struct inode *inode = file_inode(filp);
+ u32 __user *user_attr = (u32 __user *)arg;
+
+ switch (cmd) {
+ case FAT_IOCTL_GET_ATTRIBUTES:
+ return fat_ioctl_get_attributes(inode, user_attr);
+ case FAT_IOCTL_SET_ATTRIBUTES:
+ return fat_ioctl_set_attributes(filp, user_attr);
+ case FAT_IOCTL_GET_VOLUME_ID:
+ return fat_ioctl_get_volume_id(inode, user_attr);
+ case FITRIM:
+ return fat_ioctl_fitrim(inode, arg);
+ default:
+ return -ENOTTY; /* Inappropriate ioctl for device */
+ }
+}
+
+static int fat_file_release(struct inode *inode, struct file *filp)
+{
+ if ((filp->f_mode & FMODE_WRITE) &&
+ MSDOS_SB(inode->i_sb)->options.flush) {
+ fat_flush_inodes(inode->i_sb, inode, NULL);
+ set_current_state(TASK_UNINTERRUPTIBLE);
+ io_schedule_timeout(HZ/10);
+ }
+ return 0;
+}
+
+int fat_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_mapping_buffers(MSDOS_SB(inode->i_sb)->fat_inode->i_mapping);
+ if (err)
+ return err;
+
+ return blkdev_issue_flush(inode->i_sb->s_bdev);
+}
+
+
+const struct file_operations fat_file_operations = {
+ .llseek = generic_file_llseek,
+ .read_iter = generic_file_read_iter,
+ .write_iter = generic_file_write_iter,
+ .mmap = generic_file_mmap,
+ .release = fat_file_release,
+ .unlocked_ioctl = fat_generic_ioctl,
+ .compat_ioctl = compat_ptr_ioctl,
+ .fsync = fat_file_fsync,
+ .splice_read = filemap_splice_read,
+ .splice_write = iter_file_splice_write,
+ .fallocate = fat_fallocate,
+};
+
+static int fat_cont_expand(struct inode *inode, loff_t size)
+{
+ struct address_space *mapping = inode->i_mapping;
+ loff_t start = inode->i_size, count = size - inode->i_size;
+ int err;
+
+ err = generic_cont_expand_simple(inode, size);
+ if (err)
+ goto out;
+
+ fat_truncate_time(inode, NULL, S_CTIME|S_MTIME);
+ mark_inode_dirty(inode);
+ if (IS_SYNC(inode)) {
+ int err2;
+
+ /*
+ * Opencode syncing since we don't have a file open to use
+ * standard fsync path.
+ */
+ 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) {
+ err = filemap_fdatawait_range(mapping, start,
+ start + count - 1);
+ }
+ }
+out:
+ return err;
+}
+
+/*
+ * Preallocate space for a file. This implements fat's fallocate file
+ * operation, which gets called from sys_fallocate system call. User
+ * space requests len bytes at offset. If FALLOC_FL_KEEP_SIZE is set
+ * we just allocate clusters without zeroing them out. Otherwise we
+ * allocate and zero out clusters via an expanding truncate.
+ */
+static long fat_fallocate(struct file *file, int mode,
+ loff_t offset, loff_t len)
+{
+ int nr_cluster; /* Number of clusters to be allocated */
+ loff_t mm_bytes; /* Number of bytes to be allocated for file */
+ loff_t ondisksize; /* block aligned on-disk size in bytes*/
+ struct inode *inode = file->f_mapping->host;
+ struct super_block *sb = inode->i_sb;
+ struct msdos_sb_info *sbi = MSDOS_SB(sb);
+ int err = 0;
+
+ /* No support for hole punch or other fallocate flags. */
+ if (mode & ~FALLOC_FL_KEEP_SIZE)
+ return -EOPNOTSUPP;
+
+ /* No support for dir */
+ if (!S_ISREG(inode->i_mode))
+ return -EOPNOTSUPP;
+
+ inode_lock(inode);
+ if (mode & FALLOC_FL_KEEP_SIZE) {
+ ondisksize = inode->i_blocks << 9;
+ if ((offset + len) <= ondisksize)
+ goto error;
+
+ /* First compute the number of clusters to be allocated */
+ mm_bytes = offset + len - ondisksize;
+ nr_cluster = (mm_bytes + (sbi->cluster_size - 1)) >>
+ sbi->cluster_bits;
+
+ /* Start the allocation.We are not zeroing out the clusters */
+ while (nr_cluster-- > 0) {
+ err = fat_add_cluster(inode);
+ if (err)
+ goto error;
+ }
+ } else {
+ if ((offset + len) <= i_size_read(inode))
+ goto error;
+
+ /* This is just an expanding truncate */
+ err = fat_cont_expand(inode, (offset + len));
+ }
+
+error:
+ inode_unlock(inode);
+ return err;
+}
+
+/* Free all clusters after the skip'th cluster. */
+static int fat_free(struct inode *inode, int skip)
+{
+ struct super_block *sb = inode->i_sb;
+ int err, wait, free_start, i_start, i_logstart;
+
+ if (MSDOS_I(inode)->i_start == 0)
+ return 0;
+
+ fat_cache_inval_inode(inode);
+
+ wait = IS_DIRSYNC(inode);
+ i_start = free_start = MSDOS_I(inode)->i_start;
+ i_logstart = MSDOS_I(inode)->i_logstart;
+
+ /* First, we write the new file size. */
+ if (!skip) {
+ MSDOS_I(inode)->i_start = 0;
+ MSDOS_I(inode)->i_logstart = 0;
+ }
+ MSDOS_I(inode)->i_attrs |= ATTR_ARCH;
+ fat_truncate_time(inode, NULL, S_CTIME|S_MTIME);
+ if (wait) {
+ err = fat_sync_inode(inode);
+ if (err) {
+ MSDOS_I(inode)->i_start = i_start;
+ MSDOS_I(inode)->i_logstart = i_logstart;
+ return err;
+ }
+ } else
+ mark_inode_dirty(inode);
+
+ /* Write a new EOF, and get the remaining cluster chain for freeing. */
+ if (skip) {
+ struct fat_entry fatent;
+ int ret, fclus, dclus;
+
+ ret = fat_get_cluster(inode, skip - 1, &fclus, &dclus);
+ if (ret < 0)
+ return ret;
+ else if (ret == FAT_ENT_EOF)
+ return 0;
+
+ fatent_init(&fatent);
+ ret = fat_ent_read(inode, &fatent, dclus);
+ if (ret == FAT_ENT_EOF) {
+ fatent_brelse(&fatent);
+ return 0;
+ } else if (ret == FAT_ENT_FREE) {
+ fat_fs_error(sb,
+ "%s: invalid cluster chain (i_pos %lld)",
+ __func__, MSDOS_I(inode)->i_pos);
+ ret = -EIO;
+ } else if (ret > 0) {
+ err = fat_ent_write(inode, &fatent, FAT_ENT_EOF, wait);
+ if (err)
+ ret = err;
+ }
+ fatent_brelse(&fatent);
+ if (ret < 0)
+ return ret;
+
+ free_start = ret;
+ }
+ inode->i_blocks = skip << (MSDOS_SB(sb)->cluster_bits - 9);
+
+ /* Freeing the remained cluster chain */
+ return fat_free_clusters(inode, free_start);
+}
+
+void fat_truncate_blocks(struct inode *inode, loff_t offset)
+{
+ struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
+ const unsigned int cluster_size = sbi->cluster_size;
+ int nr_clusters;
+
+ /*
+ * This protects against truncating a file bigger than it was then
+ * trying to write into the hole.
+ */
+ if (MSDOS_I(inode)->mmu_private > offset)
+ MSDOS_I(inode)->mmu_private = offset;
+
+ nr_clusters = (offset + (cluster_size - 1)) >> sbi->cluster_bits;
+
+ fat_free(inode, nr_clusters);
+ fat_flush_inodes(inode->i_sb, inode, NULL);
+}
+
+int fat_getattr(struct mnt_idmap *idmap, const struct path *path,
+ struct kstat *stat, u32 request_mask, unsigned int flags)
+{
+ struct inode *inode = d_inode(path->dentry);
+ struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
+
+ generic_fillattr(idmap, request_mask, inode, stat);
+ stat->blksize = sbi->cluster_size;
+
+ if (sbi->options.nfs == FAT_NFS_NOSTALE_RO) {
+ /* Use i_pos for ino. This is used as fileid of nfs. */
+ stat->ino = fat_i_pos_read(sbi, inode);
+ }
+
+ if (sbi->options.isvfat && request_mask & STATX_BTIME) {
+ stat->result_mask |= STATX_BTIME;
+ stat->btime = MSDOS_I(inode)->i_crtime;
+ }
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(fat_getattr);
+
+static int fat_sanitize_mode(const struct msdos_sb_info *sbi,
+ struct inode *inode, umode_t *mode_ptr)
+{
+ umode_t mask, perm;
+
+ /*
+ * Note, the basic check is already done by a caller of
+ * (attr->ia_mode & ~FAT_VALID_MODE)
+ */
+
+ if (S_ISREG(inode->i_mode))
+ mask = sbi->options.fs_fmask;
+ else
+ mask = sbi->options.fs_dmask;
+
+ perm = *mode_ptr & ~(S_IFMT | mask);
+
+ /*
+ * Of the r and x bits, all (subject to umask) must be present. Of the
+ * w bits, either all (subject to umask) or none must be present.
+ *
+ * If fat_mode_can_hold_ro(inode) is false, can't change w bits.
+ */
+ if ((perm & (S_IRUGO | S_IXUGO)) != (inode->i_mode & (S_IRUGO|S_IXUGO)))
+ return -EPERM;
+ if (fat_mode_can_hold_ro(inode)) {
+ if ((perm & S_IWUGO) && ((perm & S_IWUGO) != (S_IWUGO & ~mask)))
+ return -EPERM;
+ } else {
+ if ((perm & S_IWUGO) != (S_IWUGO & ~mask))
+ return -EPERM;
+ }
+
+ *mode_ptr &= S_IFMT | perm;
+
+ return 0;
+}
+
+static int fat_allow_set_time(struct mnt_idmap *idmap,
+ struct msdos_sb_info *sbi, struct inode *inode)
+{
+ umode_t allow_utime = sbi->options.allow_utime;
+
+ if (!vfsuid_eq_kuid(i_uid_into_vfsuid(idmap, inode),
+ current_fsuid())) {
+ if (vfsgid_in_group_p(i_gid_into_vfsgid(idmap, inode)))
+ allow_utime >>= 3;
+ if (allow_utime & MAY_WRITE)
+ return 1;
+ }
+
+ /* use a default check */
+ return 0;
+}
+
+#define TIMES_SET_FLAGS (ATTR_MTIME_SET | ATTR_ATIME_SET | ATTR_TIMES_SET)
+/* valid file mode bits */
+#define FAT_VALID_MODE (S_IFREG | S_IFDIR | S_IRWXUGO)
+
+int fat_setattr(struct mnt_idmap *idmap, struct dentry *dentry,
+ struct iattr *attr)
+{
+ struct msdos_sb_info *sbi = MSDOS_SB(dentry->d_sb);
+ struct inode *inode = d_inode(dentry);
+ unsigned int ia_valid;
+ int error;
+
+ /* Check for setting the inode time. */
+ ia_valid = attr->ia_valid;
+ if (ia_valid & TIMES_SET_FLAGS) {
+ if (fat_allow_set_time(idmap, sbi, inode))
+ attr->ia_valid &= ~TIMES_SET_FLAGS;
+ }
+
+ error = setattr_prepare(idmap, dentry, attr);
+ attr->ia_valid = ia_valid;
+ if (error) {
+ if (sbi->options.quiet)
+ error = 0;
+ goto out;
+ }
+
+ /*
+ * Expand the file. Since inode_setattr() updates ->i_size
+ * before calling the ->truncate(), but FAT needs to fill the
+ * hole before it. XXX: this is no longer true with new truncate
+ * sequence.
+ */
+ if (attr->ia_valid & ATTR_SIZE) {
+ inode_dio_wait(inode);
+
+ if (attr->ia_size > inode->i_size) {
+ error = fat_cont_expand(inode, attr->ia_size);
+ if (error || attr->ia_valid == ATTR_SIZE)
+ goto out;
+ attr->ia_valid &= ~ATTR_SIZE;
+ }
+ }
+
+ if (((attr->ia_valid & ATTR_UID) &&
+ (!uid_eq(from_vfsuid(idmap, i_user_ns(inode), attr->ia_vfsuid),
+ sbi->options.fs_uid))) ||
+ ((attr->ia_valid & ATTR_GID) &&
+ (!gid_eq(from_vfsgid(idmap, i_user_ns(inode), attr->ia_vfsgid),
+ sbi->options.fs_gid))) ||
+ ((attr->ia_valid & ATTR_MODE) &&
+ (attr->ia_mode & ~FAT_VALID_MODE)))
+ error = -EPERM;
+
+ if (error) {
+ if (sbi->options.quiet)
+ error = 0;
+ goto out;
+ }
+
+ /*
+ * We don't return -EPERM here. Yes, strange, but this is too
+ * old behavior.
+ */
+ if (attr->ia_valid & ATTR_MODE) {
+ if (fat_sanitize_mode(sbi, inode, &attr->ia_mode) < 0)
+ attr->ia_valid &= ~ATTR_MODE;
+ }
+
+ if (attr->ia_valid & ATTR_SIZE) {
+ error = fat_block_truncate_page(inode, attr->ia_size);
+ if (error)
+ goto out;
+ down_write(&MSDOS_I(inode)->truncate_lock);
+ truncate_setsize(inode, attr->ia_size);
+ fat_truncate_blocks(inode, attr->ia_size);
+ up_write(&MSDOS_I(inode)->truncate_lock);
+ }
+
+ /*
+ * setattr_copy can't truncate these appropriately, so we'll
+ * copy them ourselves
+ */
+ if (attr->ia_valid & ATTR_ATIME)
+ fat_truncate_time(inode, &attr->ia_atime, S_ATIME);
+ if (attr->ia_valid & ATTR_CTIME)
+ fat_truncate_time(inode, &attr->ia_ctime, S_CTIME);
+ if (attr->ia_valid & ATTR_MTIME)
+ fat_truncate_time(inode, &attr->ia_mtime, S_MTIME);
+ attr->ia_valid &= ~(ATTR_ATIME|ATTR_CTIME|ATTR_MTIME);
+
+ setattr_copy(idmap, inode, attr);
+ mark_inode_dirty(inode);
+out:
+ return error;
+}
+EXPORT_SYMBOL_GPL(fat_setattr);
+
+const struct inode_operations fat_file_inode_operations = {
+ .setattr = fat_setattr,
+ .getattr = fat_getattr,
+ .update_time = fat_update_time,
+};