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-rw-r--r--fs/nilfs2/dir.c679
1 files changed, 679 insertions, 0 deletions
diff --git a/fs/nilfs2/dir.c b/fs/nilfs2/dir.c
new file mode 100644
index 000000000..decd64713
--- /dev/null
+++ b/fs/nilfs2/dir.c
@@ -0,0 +1,679 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * NILFS directory entry operations
+ *
+ * Copyright (C) 2005-2008 Nippon Telegraph and Telephone Corporation.
+ *
+ * Modified for NILFS by Amagai Yoshiji.
+ */
+/*
+ * linux/fs/ext2/dir.c
+ *
+ * Copyright (C) 1992, 1993, 1994, 1995
+ * Remy Card (card@masi.ibp.fr)
+ * Laboratoire MASI - Institut Blaise Pascal
+ * Universite Pierre et Marie Curie (Paris VI)
+ *
+ * from
+ *
+ * linux/fs/minix/dir.c
+ *
+ * Copyright (C) 1991, 1992 Linus Torvalds
+ *
+ * ext2 directory handling functions
+ *
+ * Big-endian to little-endian byte-swapping/bitmaps by
+ * David S. Miller (davem@caip.rutgers.edu), 1995
+ *
+ * All code that works with directory layout had been switched to pagecache
+ * and moved here. AV
+ */
+
+#include <linux/pagemap.h>
+#include "nilfs.h"
+#include "page.h"
+
+static inline unsigned int nilfs_rec_len_from_disk(__le16 dlen)
+{
+ unsigned int len = le16_to_cpu(dlen);
+
+#if (PAGE_SIZE >= 65536)
+ if (len == NILFS_MAX_REC_LEN)
+ return 1 << 16;
+#endif
+ return len;
+}
+
+static inline __le16 nilfs_rec_len_to_disk(unsigned int len)
+{
+#if (PAGE_SIZE >= 65536)
+ if (len == (1 << 16))
+ return cpu_to_le16(NILFS_MAX_REC_LEN);
+
+ BUG_ON(len > (1 << 16));
+#endif
+ return cpu_to_le16(len);
+}
+
+/*
+ * nilfs uses block-sized chunks. Arguably, sector-sized ones would be
+ * more robust, but we have what we have
+ */
+static inline unsigned int nilfs_chunk_size(struct inode *inode)
+{
+ return inode->i_sb->s_blocksize;
+}
+
+static inline void nilfs_put_page(struct page *page)
+{
+ kunmap(page);
+ put_page(page);
+}
+
+/*
+ * Return the offset into page `page_nr' of the last valid
+ * byte in that page, plus one.
+ */
+static unsigned int nilfs_last_byte(struct inode *inode, unsigned long page_nr)
+{
+ unsigned int last_byte = inode->i_size;
+
+ last_byte -= page_nr << PAGE_SHIFT;
+ if (last_byte > PAGE_SIZE)
+ last_byte = PAGE_SIZE;
+ return last_byte;
+}
+
+static int nilfs_prepare_chunk(struct page *page, unsigned int from,
+ unsigned int to)
+{
+ loff_t pos = page_offset(page) + from;
+
+ return __block_write_begin(page, pos, to - from, nilfs_get_block);
+}
+
+static void nilfs_commit_chunk(struct page *page,
+ struct address_space *mapping,
+ unsigned int from, unsigned int to)
+{
+ struct inode *dir = mapping->host;
+ loff_t pos = page_offset(page) + from;
+ unsigned int len = to - from;
+ unsigned int nr_dirty, copied;
+ int err;
+
+ nr_dirty = nilfs_page_count_clean_buffers(page, from, to);
+ copied = block_write_end(NULL, mapping, pos, len, len, page, NULL);
+ if (pos + copied > dir->i_size)
+ i_size_write(dir, pos + copied);
+ if (IS_DIRSYNC(dir))
+ nilfs_set_transaction_flag(NILFS_TI_SYNC);
+ err = nilfs_set_file_dirty(dir, nr_dirty);
+ WARN_ON(err); /* do not happen */
+ unlock_page(page);
+}
+
+static bool nilfs_check_page(struct page *page)
+{
+ struct inode *dir = page->mapping->host;
+ struct super_block *sb = dir->i_sb;
+ unsigned int chunk_size = nilfs_chunk_size(dir);
+ char *kaddr = page_address(page);
+ unsigned int offs, rec_len;
+ unsigned int limit = PAGE_SIZE;
+ struct nilfs_dir_entry *p;
+ char *error;
+
+ if ((dir->i_size >> PAGE_SHIFT) == page->index) {
+ limit = dir->i_size & ~PAGE_MASK;
+ if (limit & (chunk_size - 1))
+ goto Ebadsize;
+ if (!limit)
+ goto out;
+ }
+ for (offs = 0; offs <= limit - NILFS_DIR_REC_LEN(1); offs += rec_len) {
+ p = (struct nilfs_dir_entry *)(kaddr + offs);
+ rec_len = nilfs_rec_len_from_disk(p->rec_len);
+
+ if (rec_len < NILFS_DIR_REC_LEN(1))
+ goto Eshort;
+ if (rec_len & 3)
+ goto Ealign;
+ if (rec_len < NILFS_DIR_REC_LEN(p->name_len))
+ goto Enamelen;
+ if (((offs + rec_len - 1) ^ offs) & ~(chunk_size-1))
+ goto Espan;
+ }
+ if (offs != limit)
+ goto Eend;
+out:
+ SetPageChecked(page);
+ return true;
+
+ /* Too bad, we had an error */
+
+Ebadsize:
+ nilfs_error(sb,
+ "size of directory #%lu is not a multiple of chunk size",
+ dir->i_ino);
+ goto fail;
+Eshort:
+ error = "rec_len is smaller than minimal";
+ goto bad_entry;
+Ealign:
+ error = "unaligned directory entry";
+ goto bad_entry;
+Enamelen:
+ error = "rec_len is too small for name_len";
+ goto bad_entry;
+Espan:
+ error = "directory entry across blocks";
+bad_entry:
+ nilfs_error(sb,
+ "bad entry in directory #%lu: %s - offset=%lu, inode=%lu, rec_len=%d, name_len=%d",
+ dir->i_ino, error, (page->index << PAGE_SHIFT) + offs,
+ (unsigned long)le64_to_cpu(p->inode),
+ rec_len, p->name_len);
+ goto fail;
+Eend:
+ p = (struct nilfs_dir_entry *)(kaddr + offs);
+ nilfs_error(sb,
+ "entry in directory #%lu spans the page boundary offset=%lu, inode=%lu",
+ dir->i_ino, (page->index << PAGE_SHIFT) + offs,
+ (unsigned long)le64_to_cpu(p->inode));
+fail:
+ SetPageError(page);
+ return false;
+}
+
+static struct page *nilfs_get_page(struct inode *dir, unsigned long n)
+{
+ struct address_space *mapping = dir->i_mapping;
+ struct page *page = read_mapping_page(mapping, n, NULL);
+
+ if (!IS_ERR(page)) {
+ kmap(page);
+ if (unlikely(!PageChecked(page))) {
+ if (!nilfs_check_page(page))
+ goto fail;
+ }
+ }
+ return page;
+
+fail:
+ nilfs_put_page(page);
+ return ERR_PTR(-EIO);
+}
+
+/*
+ * NOTE! unlike strncmp, nilfs_match returns 1 for success, 0 for failure.
+ *
+ * len <= NILFS_NAME_LEN and de != NULL are guaranteed by caller.
+ */
+static int
+nilfs_match(int len, const unsigned char *name, struct nilfs_dir_entry *de)
+{
+ if (len != de->name_len)
+ return 0;
+ if (!de->inode)
+ return 0;
+ return !memcmp(name, de->name, len);
+}
+
+/*
+ * p is at least 6 bytes before the end of page
+ */
+static struct nilfs_dir_entry *nilfs_next_entry(struct nilfs_dir_entry *p)
+{
+ return (struct nilfs_dir_entry *)((char *)p +
+ nilfs_rec_len_from_disk(p->rec_len));
+}
+
+static unsigned char
+nilfs_filetype_table[NILFS_FT_MAX] = {
+ [NILFS_FT_UNKNOWN] = DT_UNKNOWN,
+ [NILFS_FT_REG_FILE] = DT_REG,
+ [NILFS_FT_DIR] = DT_DIR,
+ [NILFS_FT_CHRDEV] = DT_CHR,
+ [NILFS_FT_BLKDEV] = DT_BLK,
+ [NILFS_FT_FIFO] = DT_FIFO,
+ [NILFS_FT_SOCK] = DT_SOCK,
+ [NILFS_FT_SYMLINK] = DT_LNK,
+};
+
+#define S_SHIFT 12
+static unsigned char
+nilfs_type_by_mode[S_IFMT >> S_SHIFT] = {
+ [S_IFREG >> S_SHIFT] = NILFS_FT_REG_FILE,
+ [S_IFDIR >> S_SHIFT] = NILFS_FT_DIR,
+ [S_IFCHR >> S_SHIFT] = NILFS_FT_CHRDEV,
+ [S_IFBLK >> S_SHIFT] = NILFS_FT_BLKDEV,
+ [S_IFIFO >> S_SHIFT] = NILFS_FT_FIFO,
+ [S_IFSOCK >> S_SHIFT] = NILFS_FT_SOCK,
+ [S_IFLNK >> S_SHIFT] = NILFS_FT_SYMLINK,
+};
+
+static void nilfs_set_de_type(struct nilfs_dir_entry *de, struct inode *inode)
+{
+ umode_t mode = inode->i_mode;
+
+ de->file_type = nilfs_type_by_mode[(mode & S_IFMT)>>S_SHIFT];
+}
+
+static int nilfs_readdir(struct file *file, struct dir_context *ctx)
+{
+ loff_t pos = ctx->pos;
+ struct inode *inode = file_inode(file);
+ struct super_block *sb = inode->i_sb;
+ unsigned int offset = pos & ~PAGE_MASK;
+ unsigned long n = pos >> PAGE_SHIFT;
+ unsigned long npages = dir_pages(inode);
+
+ if (pos > inode->i_size - NILFS_DIR_REC_LEN(1))
+ return 0;
+
+ for ( ; n < npages; n++, offset = 0) {
+ char *kaddr, *limit;
+ struct nilfs_dir_entry *de;
+ struct page *page = nilfs_get_page(inode, n);
+
+ if (IS_ERR(page)) {
+ nilfs_error(sb, "bad page in #%lu", inode->i_ino);
+ ctx->pos += PAGE_SIZE - offset;
+ return -EIO;
+ }
+ kaddr = page_address(page);
+ de = (struct nilfs_dir_entry *)(kaddr + offset);
+ limit = kaddr + nilfs_last_byte(inode, n) -
+ NILFS_DIR_REC_LEN(1);
+ for ( ; (char *)de <= limit; de = nilfs_next_entry(de)) {
+ if (de->rec_len == 0) {
+ nilfs_error(sb, "zero-length directory entry");
+ nilfs_put_page(page);
+ return -EIO;
+ }
+ if (de->inode) {
+ unsigned char t;
+
+ if (de->file_type < NILFS_FT_MAX)
+ t = nilfs_filetype_table[de->file_type];
+ else
+ t = DT_UNKNOWN;
+
+ if (!dir_emit(ctx, de->name, de->name_len,
+ le64_to_cpu(de->inode), t)) {
+ nilfs_put_page(page);
+ return 0;
+ }
+ }
+ ctx->pos += nilfs_rec_len_from_disk(de->rec_len);
+ }
+ nilfs_put_page(page);
+ }
+ return 0;
+}
+
+/*
+ * nilfs_find_entry()
+ *
+ * finds an entry in the specified directory with the wanted name. It
+ * returns the page in which the entry was found, and the entry itself
+ * (as a parameter - res_dir). Page is returned mapped and unlocked.
+ * Entry is guaranteed to be valid.
+ */
+struct nilfs_dir_entry *
+nilfs_find_entry(struct inode *dir, const struct qstr *qstr,
+ struct page **res_page)
+{
+ const unsigned char *name = qstr->name;
+ int namelen = qstr->len;
+ unsigned int reclen = NILFS_DIR_REC_LEN(namelen);
+ unsigned long start, n;
+ unsigned long npages = dir_pages(dir);
+ struct page *page = NULL;
+ struct nilfs_inode_info *ei = NILFS_I(dir);
+ struct nilfs_dir_entry *de;
+
+ if (npages == 0)
+ goto out;
+
+ /* OFFSET_CACHE */
+ *res_page = NULL;
+
+ start = ei->i_dir_start_lookup;
+ if (start >= npages)
+ start = 0;
+ n = start;
+ do {
+ char *kaddr;
+
+ page = nilfs_get_page(dir, n);
+ if (!IS_ERR(page)) {
+ kaddr = page_address(page);
+ de = (struct nilfs_dir_entry *)kaddr;
+ kaddr += nilfs_last_byte(dir, n) - reclen;
+ while ((char *) de <= kaddr) {
+ if (de->rec_len == 0) {
+ nilfs_error(dir->i_sb,
+ "zero-length directory entry");
+ nilfs_put_page(page);
+ goto out;
+ }
+ if (nilfs_match(namelen, name, de))
+ goto found;
+ de = nilfs_next_entry(de);
+ }
+ nilfs_put_page(page);
+ }
+ if (++n >= npages)
+ n = 0;
+ /* next page is past the blocks we've got */
+ if (unlikely(n > (dir->i_blocks >> (PAGE_SHIFT - 9)))) {
+ nilfs_error(dir->i_sb,
+ "dir %lu size %lld exceeds block count %llu",
+ dir->i_ino, dir->i_size,
+ (unsigned long long)dir->i_blocks);
+ goto out;
+ }
+ } while (n != start);
+out:
+ return NULL;
+
+found:
+ *res_page = page;
+ ei->i_dir_start_lookup = n;
+ return de;
+}
+
+struct nilfs_dir_entry *nilfs_dotdot(struct inode *dir, struct page **p)
+{
+ struct page *page = nilfs_get_page(dir, 0);
+ struct nilfs_dir_entry *de = NULL;
+
+ if (!IS_ERR(page)) {
+ de = nilfs_next_entry(
+ (struct nilfs_dir_entry *)page_address(page));
+ *p = page;
+ }
+ return de;
+}
+
+ino_t nilfs_inode_by_name(struct inode *dir, const struct qstr *qstr)
+{
+ ino_t res = 0;
+ struct nilfs_dir_entry *de;
+ struct page *page;
+
+ de = nilfs_find_entry(dir, qstr, &page);
+ if (de) {
+ res = le64_to_cpu(de->inode);
+ kunmap(page);
+ put_page(page);
+ }
+ return res;
+}
+
+/* Releases the page */
+void nilfs_set_link(struct inode *dir, struct nilfs_dir_entry *de,
+ struct page *page, struct inode *inode)
+{
+ unsigned int from = (char *)de - (char *)page_address(page);
+ unsigned int to = from + nilfs_rec_len_from_disk(de->rec_len);
+ struct address_space *mapping = page->mapping;
+ int err;
+
+ lock_page(page);
+ err = nilfs_prepare_chunk(page, from, to);
+ BUG_ON(err);
+ de->inode = cpu_to_le64(inode->i_ino);
+ nilfs_set_de_type(de, inode);
+ nilfs_commit_chunk(page, mapping, from, to);
+ nilfs_put_page(page);
+ dir->i_mtime = dir->i_ctime = current_time(dir);
+}
+
+/*
+ * Parent is locked.
+ */
+int nilfs_add_link(struct dentry *dentry, struct inode *inode)
+{
+ struct inode *dir = d_inode(dentry->d_parent);
+ const unsigned char *name = dentry->d_name.name;
+ int namelen = dentry->d_name.len;
+ unsigned int chunk_size = nilfs_chunk_size(dir);
+ unsigned int reclen = NILFS_DIR_REC_LEN(namelen);
+ unsigned short rec_len, name_len;
+ struct page *page = NULL;
+ struct nilfs_dir_entry *de;
+ unsigned long npages = dir_pages(dir);
+ unsigned long n;
+ char *kaddr;
+ unsigned int from, to;
+ int err;
+
+ /*
+ * We take care of directory expansion in the same loop.
+ * This code plays outside i_size, so it locks the page
+ * to protect that region.
+ */
+ for (n = 0; n <= npages; n++) {
+ char *dir_end;
+
+ page = nilfs_get_page(dir, n);
+ err = PTR_ERR(page);
+ if (IS_ERR(page))
+ goto out;
+ lock_page(page);
+ kaddr = page_address(page);
+ dir_end = kaddr + nilfs_last_byte(dir, n);
+ de = (struct nilfs_dir_entry *)kaddr;
+ kaddr += PAGE_SIZE - reclen;
+ while ((char *)de <= kaddr) {
+ if ((char *)de == dir_end) {
+ /* We hit i_size */
+ name_len = 0;
+ rec_len = chunk_size;
+ de->rec_len = nilfs_rec_len_to_disk(chunk_size);
+ de->inode = 0;
+ goto got_it;
+ }
+ if (de->rec_len == 0) {
+ nilfs_error(dir->i_sb,
+ "zero-length directory entry");
+ err = -EIO;
+ goto out_unlock;
+ }
+ err = -EEXIST;
+ if (nilfs_match(namelen, name, de))
+ goto out_unlock;
+ name_len = NILFS_DIR_REC_LEN(de->name_len);
+ rec_len = nilfs_rec_len_from_disk(de->rec_len);
+ if (!de->inode && rec_len >= reclen)
+ goto got_it;
+ if (rec_len >= name_len + reclen)
+ goto got_it;
+ de = (struct nilfs_dir_entry *)((char *)de + rec_len);
+ }
+ unlock_page(page);
+ nilfs_put_page(page);
+ }
+ BUG();
+ return -EINVAL;
+
+got_it:
+ from = (char *)de - (char *)page_address(page);
+ to = from + rec_len;
+ err = nilfs_prepare_chunk(page, from, to);
+ if (err)
+ goto out_unlock;
+ if (de->inode) {
+ struct nilfs_dir_entry *de1;
+
+ de1 = (struct nilfs_dir_entry *)((char *)de + name_len);
+ de1->rec_len = nilfs_rec_len_to_disk(rec_len - name_len);
+ de->rec_len = nilfs_rec_len_to_disk(name_len);
+ de = de1;
+ }
+ de->name_len = namelen;
+ memcpy(de->name, name, namelen);
+ de->inode = cpu_to_le64(inode->i_ino);
+ nilfs_set_de_type(de, inode);
+ nilfs_commit_chunk(page, page->mapping, from, to);
+ dir->i_mtime = dir->i_ctime = current_time(dir);
+ nilfs_mark_inode_dirty(dir);
+ /* OFFSET_CACHE */
+out_put:
+ nilfs_put_page(page);
+out:
+ return err;
+out_unlock:
+ unlock_page(page);
+ goto out_put;
+}
+
+/*
+ * nilfs_delete_entry deletes a directory entry by merging it with the
+ * previous entry. Page is up-to-date. Releases the page.
+ */
+int nilfs_delete_entry(struct nilfs_dir_entry *dir, struct page *page)
+{
+ struct address_space *mapping = page->mapping;
+ struct inode *inode = mapping->host;
+ char *kaddr = page_address(page);
+ unsigned int from, to;
+ struct nilfs_dir_entry *de, *pde = NULL;
+ int err;
+
+ from = ((char *)dir - kaddr) & ~(nilfs_chunk_size(inode) - 1);
+ to = ((char *)dir - kaddr) + nilfs_rec_len_from_disk(dir->rec_len);
+ de = (struct nilfs_dir_entry *)(kaddr + from);
+
+ while ((char *)de < (char *)dir) {
+ if (de->rec_len == 0) {
+ nilfs_error(inode->i_sb,
+ "zero-length directory entry");
+ err = -EIO;
+ goto out;
+ }
+ pde = de;
+ de = nilfs_next_entry(de);
+ }
+ if (pde)
+ from = (char *)pde - (char *)page_address(page);
+ lock_page(page);
+ err = nilfs_prepare_chunk(page, from, to);
+ BUG_ON(err);
+ if (pde)
+ pde->rec_len = nilfs_rec_len_to_disk(to - from);
+ dir->inode = 0;
+ nilfs_commit_chunk(page, mapping, from, to);
+ inode->i_ctime = inode->i_mtime = current_time(inode);
+out:
+ nilfs_put_page(page);
+ return err;
+}
+
+/*
+ * Set the first fragment of directory.
+ */
+int nilfs_make_empty(struct inode *inode, struct inode *parent)
+{
+ struct address_space *mapping = inode->i_mapping;
+ struct page *page = grab_cache_page(mapping, 0);
+ unsigned int chunk_size = nilfs_chunk_size(inode);
+ struct nilfs_dir_entry *de;
+ int err;
+ void *kaddr;
+
+ if (!page)
+ return -ENOMEM;
+
+ err = nilfs_prepare_chunk(page, 0, chunk_size);
+ if (unlikely(err)) {
+ unlock_page(page);
+ goto fail;
+ }
+ kaddr = kmap_atomic(page);
+ memset(kaddr, 0, chunk_size);
+ de = (struct nilfs_dir_entry *)kaddr;
+ de->name_len = 1;
+ de->rec_len = nilfs_rec_len_to_disk(NILFS_DIR_REC_LEN(1));
+ memcpy(de->name, ".\0\0", 4);
+ de->inode = cpu_to_le64(inode->i_ino);
+ nilfs_set_de_type(de, inode);
+
+ de = (struct nilfs_dir_entry *)(kaddr + NILFS_DIR_REC_LEN(1));
+ de->name_len = 2;
+ de->rec_len = nilfs_rec_len_to_disk(chunk_size - NILFS_DIR_REC_LEN(1));
+ de->inode = cpu_to_le64(parent->i_ino);
+ memcpy(de->name, "..\0", 4);
+ nilfs_set_de_type(de, inode);
+ kunmap_atomic(kaddr);
+ nilfs_commit_chunk(page, mapping, 0, chunk_size);
+fail:
+ put_page(page);
+ return err;
+}
+
+/*
+ * routine to check that the specified directory is empty (for rmdir)
+ */
+int nilfs_empty_dir(struct inode *inode)
+{
+ struct page *page = NULL;
+ unsigned long i, npages = dir_pages(inode);
+
+ for (i = 0; i < npages; i++) {
+ char *kaddr;
+ struct nilfs_dir_entry *de;
+
+ page = nilfs_get_page(inode, i);
+ if (IS_ERR(page))
+ continue;
+
+ kaddr = page_address(page);
+ de = (struct nilfs_dir_entry *)kaddr;
+ kaddr += nilfs_last_byte(inode, i) - NILFS_DIR_REC_LEN(1);
+
+ while ((char *)de <= kaddr) {
+ if (de->rec_len == 0) {
+ nilfs_error(inode->i_sb,
+ "zero-length directory entry (kaddr=%p, de=%p)",
+ kaddr, de);
+ goto not_empty;
+ }
+ if (de->inode != 0) {
+ /* check for . and .. */
+ if (de->name[0] != '.')
+ goto not_empty;
+ if (de->name_len > 2)
+ goto not_empty;
+ if (de->name_len < 2) {
+ if (de->inode !=
+ cpu_to_le64(inode->i_ino))
+ goto not_empty;
+ } else if (de->name[1] != '.')
+ goto not_empty;
+ }
+ de = nilfs_next_entry(de);
+ }
+ nilfs_put_page(page);
+ }
+ return 1;
+
+not_empty:
+ nilfs_put_page(page);
+ return 0;
+}
+
+const struct file_operations nilfs_dir_operations = {
+ .llseek = generic_file_llseek,
+ .read = generic_read_dir,
+ .iterate_shared = nilfs_readdir,
+ .unlocked_ioctl = nilfs_ioctl,
+#ifdef CONFIG_COMPAT
+ .compat_ioctl = nilfs_compat_ioctl,
+#endif /* CONFIG_COMPAT */
+ .fsync = nilfs_sync_file,
+
+};
generated by cgit v1.2.3 (git 2.39.1) at 2024-10-31 10:57:07 +0000