diff options
author | Namjae Jeon <namjae.jeon@samsung.com> | 2020-03-02 15:21:36 +0900 |
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committer | Al Viro <viro@zeniv.linux.org.uk> | 2020-03-05 21:00:40 -0500 |
commit | 98d917047e8b7f4bb2ff61d81b0ccd94a00444f9 (patch) | |
tree | f223527f8fc498be19ff8a680c8f22c015acd8c5 | |
parent | ca06197382bde0a3bc20215595d1c9ce20c6e341 (diff) |
exfat: add file operations
This adds the implementation of file operations for exfat.
Signed-off-by: Namjae Jeon <namjae.jeon@samsung.com>
Signed-off-by: Sungjong Seo <sj1557.seo@samsung.com>
Reviewed-by: Pali Rohár <pali.rohar@gmail.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
-rw-r--r-- | fs/exfat/file.c | 360 |
1 files changed, 360 insertions, 0 deletions
diff --git a/fs/exfat/file.c b/fs/exfat/file.c new file mode 100644 index 000000000000..483f683757aa --- /dev/null +++ b/fs/exfat/file.c @@ -0,0 +1,360 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * Copyright (C) 2012-2013 Samsung Electronics Co., Ltd. + */ + +#include <linux/slab.h> +#include <linux/cred.h> +#include <linux/buffer_head.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 exfat_dentry *ep, *ep2; + struct super_block *sb = inode->i_sb; + struct exfat_sb_info *sbi = EXFAT_SB(sb); + struct exfat_inode_info *ei = EXFAT_I(inode); + struct exfat_entry_set_cache *es = NULL; + int evict = (ei->dir.dir == DIR_DELETED) ? 1 : 0; + + /* check if the given file ID is opened */ + if (ei->type != TYPE_FILE && ei->type != TYPE_DIR) + return -EPERM; + + exfat_set_vol_flags(sb, VOL_DIRTY); + + num_clusters_new = EXFAT_B_TO_CLU_ROUND_UP(i_size_read(inode), sbi); + num_clusters_phys = + EXFAT_B_TO_CLU_ROUND_UP(EXFAT_I(inode)->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 (!evict) { + struct timespec64 ts; + + es = exfat_get_dentry_set(sb, &(ei->dir), ei->entry, + ES_ALL_ENTRIES, &ep); + if (!es) + return -EIO; + ep2 = ep + 1; + + ts = current_time(inode); + exfat_set_entry_time(sbi, &ts, + &ep->dentry.file.modify_tz, + &ep->dentry.file.modify_time, + &ep->dentry.file.modify_date, + &ep->dentry.file.modify_time_ms); + ep->dentry.file.attr = cpu_to_le16(ei->attr); + + /* File size should be zero if there is no cluster allocated */ + if (ei->start_clu == EXFAT_EOF_CLUSTER) { + ep->dentry.stream.valid_size = 0; + ep->dentry.stream.size = 0; + } else { + ep->dentry.stream.valid_size = cpu_to_le64(new_size); + ep->dentry.stream.size = ep->dentry.stream.valid_size; + } + + if (new_size == 0) { + /* Any directory can not be truncated to zero */ + WARN_ON(ei->type != TYPE_FILE); + + ep2->dentry.stream.flags = ALLOC_FAT_CHAIN; + ep2->dentry.stream.start_clu = EXFAT_FREE_CLUSTER; + } + + if (exfat_update_dir_chksum_with_entry_set(sb, es, + inode_needs_sync(inode))) + return -EIO; + kfree(es); + } + + /* 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; + if (ei->rwoffset > new_size) + ei->rwoffset = new_size; + + /* 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; + + exfat_set_vol_flags(sb, VOL_CLEAN); + + 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); + unsigned int blocksize = 1 << inode->i_blkbits; + loff_t aligned_size; + int err; + + mutex_lock(&sbi->s_lock); + if (EXFAT_I(inode)->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_ctime = inode->i_mtime = current_time(inode); + if (IS_DIRSYNC(inode)) + exfat_sync_inode(inode); + else + mark_inode_dirty(inode); + + inode->i_blocks = ((i_size_read(inode) + (sbi->cluster_size - 1)) & + ~(sbi->cluster_size - 1)) >> inode->i_blkbits; +write_size: + aligned_size = i_size_read(inode); + if (aligned_size & (blocksize - 1)) { + aligned_size |= (blocksize - 1); + aligned_size++; + } + + if (EXFAT_I(inode)->i_size_ondisk > i_size_read(inode)) + EXFAT_I(inode)->i_size_ondisk = aligned_size; + + if (EXFAT_I(inode)->i_size_aligned > i_size_read(inode)) + EXFAT_I(inode)->i_size_aligned = aligned_size; + mutex_unlock(&sbi->s_lock); +} + +int exfat_getattr(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(inode, stat); + 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 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(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) { + 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_truncate(inode, attr->ia_size); + up_write(&EXFAT_I(inode)->truncate_lock); + } + + setattr_copy(inode, attr); + mark_inode_dirty(inode); + +out: + return error; +} + +const struct file_operations exfat_file_operations = { + .llseek = generic_file_llseek, + .read_iter = generic_file_read_iter, + .write_iter = generic_file_write_iter, + .mmap = generic_file_mmap, + .fsync = generic_file_fsync, + .splice_read = generic_file_splice_read, +}; + +const struct inode_operations exfat_file_inode_operations = { + .setattr = exfat_setattr, + .getattr = exfat_getattr, +}; |