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731 lines
18 KiB
731 lines
18 KiB
// SPDX-License-Identifier: GPL-2.0 |
|
/* |
|
* linux/fs/ext2/dir.c |
|
* |
|
* Copyright (C) 1992, 1993, 1994, 1995 |
|
* Remy Card ([email protected]) |
|
* Laboratoire MASI - Institut Blaise Pascal |
|
* Universite Pierre et Marie Curie (Paris VI) |
|
* |
|
* from |
|
* |
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* 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 ([email protected]), 1995 |
|
* |
|
* All code that works with directory layout had been switched to pagecache |
|
* and moved here. AV |
|
*/ |
|
|
|
#include "ext2.h" |
|
#include <linux/buffer_head.h> |
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#include <linux/pagemap.h> |
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#include <linux/swap.h> |
|
#include <linux/iversion.h> |
|
|
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typedef struct ext2_dir_entry_2 ext2_dirent; |
|
|
|
/* |
|
* Tests against MAX_REC_LEN etc were put in place for 64k block |
|
* sizes; if that is not possible on this arch, we can skip |
|
* those tests and speed things up. |
|
*/ |
|
static inline unsigned ext2_rec_len_from_disk(__le16 dlen) |
|
{ |
|
unsigned len = le16_to_cpu(dlen); |
|
|
|
#if (PAGE_SIZE >= 65536) |
|
if (len == EXT2_MAX_REC_LEN) |
|
return 1 << 16; |
|
#endif |
|
return len; |
|
} |
|
|
|
static inline __le16 ext2_rec_len_to_disk(unsigned len) |
|
{ |
|
#if (PAGE_SIZE >= 65536) |
|
if (len == (1 << 16)) |
|
return cpu_to_le16(EXT2_MAX_REC_LEN); |
|
else |
|
BUG_ON(len > (1 << 16)); |
|
#endif |
|
return cpu_to_le16(len); |
|
} |
|
|
|
/* |
|
* ext2 uses block-sized chunks. Arguably, sector-sized ones would be |
|
* more robust, but we have what we have |
|
*/ |
|
static inline unsigned ext2_chunk_size(struct inode *inode) |
|
{ |
|
return inode->i_sb->s_blocksize; |
|
} |
|
|
|
/* |
|
* Return the offset into page `page_nr' of the last valid |
|
* byte in that page, plus one. |
|
*/ |
|
static unsigned |
|
ext2_last_byte(struct inode *inode, unsigned long page_nr) |
|
{ |
|
unsigned 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 ext2_commit_chunk(struct page *page, loff_t pos, unsigned len) |
|
{ |
|
struct address_space *mapping = page->mapping; |
|
struct inode *dir = mapping->host; |
|
int err = 0; |
|
|
|
inode_inc_iversion(dir); |
|
block_write_end(NULL, mapping, pos, len, len, page, NULL); |
|
|
|
if (pos+len > dir->i_size) { |
|
i_size_write(dir, pos+len); |
|
mark_inode_dirty(dir); |
|
} |
|
|
|
if (IS_DIRSYNC(dir)) { |
|
err = write_one_page(page); |
|
if (!err) |
|
err = sync_inode_metadata(dir, 1); |
|
} else { |
|
unlock_page(page); |
|
} |
|
|
|
return err; |
|
} |
|
|
|
static bool ext2_check_page(struct page *page, int quiet, char *kaddr) |
|
{ |
|
struct inode *dir = page->mapping->host; |
|
struct super_block *sb = dir->i_sb; |
|
unsigned chunk_size = ext2_chunk_size(dir); |
|
u32 max_inumber = le32_to_cpu(EXT2_SB(sb)->s_es->s_inodes_count); |
|
unsigned offs, rec_len; |
|
unsigned limit = PAGE_SIZE; |
|
ext2_dirent *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 - EXT2_DIR_REC_LEN(1); offs += rec_len) { |
|
p = (ext2_dirent *)(kaddr + offs); |
|
rec_len = ext2_rec_len_from_disk(p->rec_len); |
|
|
|
if (unlikely(rec_len < EXT2_DIR_REC_LEN(1))) |
|
goto Eshort; |
|
if (unlikely(rec_len & 3)) |
|
goto Ealign; |
|
if (unlikely(rec_len < EXT2_DIR_REC_LEN(p->name_len))) |
|
goto Enamelen; |
|
if (unlikely(((offs + rec_len - 1) ^ offs) & ~(chunk_size-1))) |
|
goto Espan; |
|
if (unlikely(le32_to_cpu(p->inode) > max_inumber)) |
|
goto Einumber; |
|
} |
|
if (offs != limit) |
|
goto Eend; |
|
out: |
|
SetPageChecked(page); |
|
return true; |
|
|
|
/* Too bad, we had an error */ |
|
|
|
Ebadsize: |
|
if (!quiet) |
|
ext2_error(sb, __func__, |
|
"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"; |
|
goto bad_entry; |
|
Einumber: |
|
error = "inode out of bounds"; |
|
bad_entry: |
|
if (!quiet) |
|
ext2_error(sb, __func__, "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) le32_to_cpu(p->inode), |
|
rec_len, p->name_len); |
|
goto fail; |
|
Eend: |
|
if (!quiet) { |
|
p = (ext2_dirent *)(kaddr + offs); |
|
ext2_error(sb, "ext2_check_page", |
|
"entry in directory #%lu spans the page boundary" |
|
"offset=%lu, inode=%lu", |
|
dir->i_ino, (page->index<<PAGE_SHIFT)+offs, |
|
(unsigned long) le32_to_cpu(p->inode)); |
|
} |
|
fail: |
|
SetPageError(page); |
|
return false; |
|
} |
|
|
|
/* |
|
* Calls to ext2_get_page()/ext2_put_page() must be nested according to the |
|
* rules documented in kmap_local_page()/kunmap_local(). |
|
* |
|
* NOTE: ext2_find_entry() and ext2_dotdot() act as a call to ext2_get_page() |
|
* and should be treated as a call to ext2_get_page() for nesting purposes. |
|
*/ |
|
static struct page * ext2_get_page(struct inode *dir, unsigned long n, |
|
int quiet, void **page_addr) |
|
{ |
|
struct address_space *mapping = dir->i_mapping; |
|
struct page *page = read_mapping_page(mapping, n, NULL); |
|
if (!IS_ERR(page)) { |
|
*page_addr = kmap_local_page(page); |
|
if (unlikely(!PageChecked(page))) { |
|
if (PageError(page) || !ext2_check_page(page, quiet, |
|
*page_addr)) |
|
goto fail; |
|
} |
|
} |
|
return page; |
|
|
|
fail: |
|
ext2_put_page(page, *page_addr); |
|
return ERR_PTR(-EIO); |
|
} |
|
|
|
/* |
|
* NOTE! unlike strncmp, ext2_match returns 1 for success, 0 for failure. |
|
* |
|
* len <= EXT2_NAME_LEN and de != NULL are guaranteed by caller. |
|
*/ |
|
static inline int ext2_match (int len, const char * const name, |
|
struct ext2_dir_entry_2 * 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 inline ext2_dirent *ext2_next_entry(ext2_dirent *p) |
|
{ |
|
return (ext2_dirent *)((char *)p + |
|
ext2_rec_len_from_disk(p->rec_len)); |
|
} |
|
|
|
static inline unsigned |
|
ext2_validate_entry(char *base, unsigned offset, unsigned mask) |
|
{ |
|
ext2_dirent *de = (ext2_dirent*)(base + offset); |
|
ext2_dirent *p = (ext2_dirent*)(base + (offset&mask)); |
|
while ((char*)p < (char*)de) { |
|
if (p->rec_len == 0) |
|
break; |
|
p = ext2_next_entry(p); |
|
} |
|
return (char *)p - base; |
|
} |
|
|
|
static inline void ext2_set_de_type(ext2_dirent *de, struct inode *inode) |
|
{ |
|
if (EXT2_HAS_INCOMPAT_FEATURE(inode->i_sb, EXT2_FEATURE_INCOMPAT_FILETYPE)) |
|
de->file_type = fs_umode_to_ftype(inode->i_mode); |
|
else |
|
de->file_type = 0; |
|
} |
|
|
|
static int |
|
ext2_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); |
|
unsigned chunk_mask = ~(ext2_chunk_size(inode)-1); |
|
bool need_revalidate = !inode_eq_iversion(inode, file->f_version); |
|
bool has_filetype; |
|
|
|
if (pos > inode->i_size - EXT2_DIR_REC_LEN(1)) |
|
return 0; |
|
|
|
has_filetype = |
|
EXT2_HAS_INCOMPAT_FEATURE(sb, EXT2_FEATURE_INCOMPAT_FILETYPE); |
|
|
|
for ( ; n < npages; n++, offset = 0) { |
|
char *kaddr, *limit; |
|
ext2_dirent *de; |
|
struct page *page = ext2_get_page(inode, n, 0, (void **)&kaddr); |
|
|
|
if (IS_ERR(page)) { |
|
ext2_error(sb, __func__, |
|
"bad page in #%lu", |
|
inode->i_ino); |
|
ctx->pos += PAGE_SIZE - offset; |
|
return PTR_ERR(page); |
|
} |
|
if (unlikely(need_revalidate)) { |
|
if (offset) { |
|
offset = ext2_validate_entry(kaddr, offset, chunk_mask); |
|
ctx->pos = (n<<PAGE_SHIFT) + offset; |
|
} |
|
file->f_version = inode_query_iversion(inode); |
|
need_revalidate = false; |
|
} |
|
de = (ext2_dirent *)(kaddr+offset); |
|
limit = kaddr + ext2_last_byte(inode, n) - EXT2_DIR_REC_LEN(1); |
|
for ( ;(char*)de <= limit; de = ext2_next_entry(de)) { |
|
if (de->rec_len == 0) { |
|
ext2_error(sb, __func__, |
|
"zero-length directory entry"); |
|
ext2_put_page(page, kaddr); |
|
return -EIO; |
|
} |
|
if (de->inode) { |
|
unsigned char d_type = DT_UNKNOWN; |
|
|
|
if (has_filetype) |
|
d_type = fs_ftype_to_dtype(de->file_type); |
|
|
|
if (!dir_emit(ctx, de->name, de->name_len, |
|
le32_to_cpu(de->inode), |
|
d_type)) { |
|
ext2_put_page(page, kaddr); |
|
return 0; |
|
} |
|
} |
|
ctx->pos += ext2_rec_len_from_disk(de->rec_len); |
|
} |
|
ext2_put_page(page, kaddr); |
|
} |
|
return 0; |
|
} |
|
|
|
/* |
|
* ext2_find_entry() |
|
* |
|
* finds an entry in the specified directory with the wanted name. It |
|
* returns the page in which the entry was found (as a parameter - res_page), |
|
* and the entry itself. Page is returned mapped and unlocked. |
|
* Entry is guaranteed to be valid. |
|
* |
|
* On Success ext2_put_page() should be called on *res_page. |
|
* |
|
* NOTE: Calls to ext2_get_page()/ext2_put_page() must be nested according to |
|
* the rules documented in kmap_local_page()/kunmap_local(). |
|
* |
|
* ext2_find_entry() and ext2_dotdot() act as a call to ext2_get_page() and |
|
* should be treated as a call to ext2_get_page() for nesting purposes. |
|
*/ |
|
struct ext2_dir_entry_2 *ext2_find_entry (struct inode *dir, |
|
const struct qstr *child, struct page **res_page, |
|
void **res_page_addr) |
|
{ |
|
const char *name = child->name; |
|
int namelen = child->len; |
|
unsigned reclen = EXT2_DIR_REC_LEN(namelen); |
|
unsigned long start, n; |
|
unsigned long npages = dir_pages(dir); |
|
struct page *page = NULL; |
|
struct ext2_inode_info *ei = EXT2_I(dir); |
|
ext2_dirent * de; |
|
void *page_addr; |
|
|
|
if (npages == 0) |
|
goto out; |
|
|
|
/* OFFSET_CACHE */ |
|
*res_page = NULL; |
|
*res_page_addr = NULL; |
|
|
|
start = ei->i_dir_start_lookup; |
|
if (start >= npages) |
|
start = 0; |
|
n = start; |
|
do { |
|
char *kaddr; |
|
page = ext2_get_page(dir, n, 0, &page_addr); |
|
if (IS_ERR(page)) |
|
return ERR_CAST(page); |
|
|
|
kaddr = page_addr; |
|
de = (ext2_dirent *) kaddr; |
|
kaddr += ext2_last_byte(dir, n) - reclen; |
|
while ((char *) de <= kaddr) { |
|
if (de->rec_len == 0) { |
|
ext2_error(dir->i_sb, __func__, |
|
"zero-length directory entry"); |
|
ext2_put_page(page, page_addr); |
|
goto out; |
|
} |
|
if (ext2_match(namelen, name, de)) |
|
goto found; |
|
de = ext2_next_entry(de); |
|
} |
|
ext2_put_page(page, page_addr); |
|
|
|
if (++n >= npages) |
|
n = 0; |
|
/* next page is past the blocks we've got */ |
|
if (unlikely(n > (dir->i_blocks >> (PAGE_SHIFT - 9)))) { |
|
ext2_error(dir->i_sb, __func__, |
|
"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 ERR_PTR(-ENOENT); |
|
|
|
found: |
|
*res_page = page; |
|
*res_page_addr = page_addr; |
|
ei->i_dir_start_lookup = n; |
|
return de; |
|
} |
|
|
|
/** |
|
* Return the '..' directory entry and the page in which the entry was found |
|
* (as a parameter - p). |
|
* |
|
* On Success ext2_put_page() should be called on *p. |
|
* |
|
* NOTE: Calls to ext2_get_page()/ext2_put_page() must be nested according to |
|
* the rules documented in kmap_local_page()/kunmap_local(). |
|
* |
|
* ext2_find_entry() and ext2_dotdot() act as a call to ext2_get_page() and |
|
* should be treated as a call to ext2_get_page() for nesting purposes. |
|
*/ |
|
struct ext2_dir_entry_2 *ext2_dotdot(struct inode *dir, struct page **p, |
|
void **pa) |
|
{ |
|
void *page_addr; |
|
struct page *page = ext2_get_page(dir, 0, 0, &page_addr); |
|
ext2_dirent *de = NULL; |
|
|
|
if (!IS_ERR(page)) { |
|
de = ext2_next_entry((ext2_dirent *) page_addr); |
|
*p = page; |
|
*pa = page_addr; |
|
} |
|
return de; |
|
} |
|
|
|
int ext2_inode_by_name(struct inode *dir, const struct qstr *child, ino_t *ino) |
|
{ |
|
struct ext2_dir_entry_2 *de; |
|
struct page *page; |
|
void *page_addr; |
|
|
|
de = ext2_find_entry(dir, child, &page, &page_addr); |
|
if (IS_ERR(de)) |
|
return PTR_ERR(de); |
|
|
|
*ino = le32_to_cpu(de->inode); |
|
ext2_put_page(page, page_addr); |
|
return 0; |
|
} |
|
|
|
static int ext2_prepare_chunk(struct page *page, loff_t pos, unsigned len) |
|
{ |
|
return __block_write_begin(page, pos, len, ext2_get_block); |
|
} |
|
|
|
void ext2_set_link(struct inode *dir, struct ext2_dir_entry_2 *de, |
|
struct page *page, void *page_addr, struct inode *inode, |
|
int update_times) |
|
{ |
|
loff_t pos = page_offset(page) + |
|
(char *) de - (char *) page_addr; |
|
unsigned len = ext2_rec_len_from_disk(de->rec_len); |
|
int err; |
|
|
|
lock_page(page); |
|
err = ext2_prepare_chunk(page, pos, len); |
|
BUG_ON(err); |
|
de->inode = cpu_to_le32(inode->i_ino); |
|
ext2_set_de_type(de, inode); |
|
err = ext2_commit_chunk(page, pos, len); |
|
if (update_times) |
|
dir->i_mtime = dir->i_ctime = current_time(dir); |
|
EXT2_I(dir)->i_flags &= ~EXT2_BTREE_FL; |
|
mark_inode_dirty(dir); |
|
} |
|
|
|
/* |
|
* Parent is locked. |
|
*/ |
|
int ext2_add_link (struct dentry *dentry, struct inode *inode) |
|
{ |
|
struct inode *dir = d_inode(dentry->d_parent); |
|
const char *name = dentry->d_name.name; |
|
int namelen = dentry->d_name.len; |
|
unsigned chunk_size = ext2_chunk_size(dir); |
|
unsigned reclen = EXT2_DIR_REC_LEN(namelen); |
|
unsigned short rec_len, name_len; |
|
struct page *page = NULL; |
|
void *page_addr = NULL; |
|
ext2_dirent * de; |
|
unsigned long npages = dir_pages(dir); |
|
unsigned long n; |
|
loff_t pos; |
|
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 *kaddr; |
|
char *dir_end; |
|
|
|
page = ext2_get_page(dir, n, 0, &page_addr); |
|
err = PTR_ERR(page); |
|
if (IS_ERR(page)) |
|
goto out; |
|
lock_page(page); |
|
kaddr = page_addr; |
|
dir_end = kaddr + ext2_last_byte(dir, n); |
|
de = (ext2_dirent *)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 = ext2_rec_len_to_disk(chunk_size); |
|
de->inode = 0; |
|
goto got_it; |
|
} |
|
if (de->rec_len == 0) { |
|
ext2_error(dir->i_sb, __func__, |
|
"zero-length directory entry"); |
|
err = -EIO; |
|
goto out_unlock; |
|
} |
|
err = -EEXIST; |
|
if (ext2_match (namelen, name, de)) |
|
goto out_unlock; |
|
name_len = EXT2_DIR_REC_LEN(de->name_len); |
|
rec_len = ext2_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 = (ext2_dirent *) ((char *) de + rec_len); |
|
} |
|
unlock_page(page); |
|
ext2_put_page(page, page_addr); |
|
} |
|
BUG(); |
|
return -EINVAL; |
|
|
|
got_it: |
|
pos = page_offset(page) + |
|
(char *)de - (char *)page_addr; |
|
err = ext2_prepare_chunk(page, pos, rec_len); |
|
if (err) |
|
goto out_unlock; |
|
if (de->inode) { |
|
ext2_dirent *de1 = (ext2_dirent *) ((char *) de + name_len); |
|
de1->rec_len = ext2_rec_len_to_disk(rec_len - name_len); |
|
de->rec_len = ext2_rec_len_to_disk(name_len); |
|
de = de1; |
|
} |
|
de->name_len = namelen; |
|
memcpy(de->name, name, namelen); |
|
de->inode = cpu_to_le32(inode->i_ino); |
|
ext2_set_de_type (de, inode); |
|
err = ext2_commit_chunk(page, pos, rec_len); |
|
dir->i_mtime = dir->i_ctime = current_time(dir); |
|
EXT2_I(dir)->i_flags &= ~EXT2_BTREE_FL; |
|
mark_inode_dirty(dir); |
|
/* OFFSET_CACHE */ |
|
out_put: |
|
ext2_put_page(page, page_addr); |
|
out: |
|
return err; |
|
out_unlock: |
|
unlock_page(page); |
|
goto out_put; |
|
} |
|
|
|
/* |
|
* ext2_delete_entry deletes a directory entry by merging it with the |
|
* previous entry. Page is up-to-date. |
|
*/ |
|
int ext2_delete_entry (struct ext2_dir_entry_2 *dir, struct page *page, |
|
char *kaddr) |
|
{ |
|
struct inode *inode = page->mapping->host; |
|
unsigned from = ((char*)dir - kaddr) & ~(ext2_chunk_size(inode)-1); |
|
unsigned to = ((char *)dir - kaddr) + |
|
ext2_rec_len_from_disk(dir->rec_len); |
|
loff_t pos; |
|
ext2_dirent * pde = NULL; |
|
ext2_dirent * de = (ext2_dirent *) (kaddr + from); |
|
int err; |
|
|
|
while ((char*)de < (char*)dir) { |
|
if (de->rec_len == 0) { |
|
ext2_error(inode->i_sb, __func__, |
|
"zero-length directory entry"); |
|
err = -EIO; |
|
goto out; |
|
} |
|
pde = de; |
|
de = ext2_next_entry(de); |
|
} |
|
if (pde) |
|
from = (char *)pde - kaddr; |
|
pos = page_offset(page) + from; |
|
lock_page(page); |
|
err = ext2_prepare_chunk(page, pos, to - from); |
|
BUG_ON(err); |
|
if (pde) |
|
pde->rec_len = ext2_rec_len_to_disk(to - from); |
|
dir->inode = 0; |
|
err = ext2_commit_chunk(page, pos, to - from); |
|
inode->i_ctime = inode->i_mtime = current_time(inode); |
|
EXT2_I(inode)->i_flags &= ~EXT2_BTREE_FL; |
|
mark_inode_dirty(inode); |
|
out: |
|
return err; |
|
} |
|
|
|
/* |
|
* Set the first fragment of directory. |
|
*/ |
|
int ext2_make_empty(struct inode *inode, struct inode *parent) |
|
{ |
|
struct page *page = grab_cache_page(inode->i_mapping, 0); |
|
unsigned chunk_size = ext2_chunk_size(inode); |
|
struct ext2_dir_entry_2 * de; |
|
int err; |
|
void *kaddr; |
|
|
|
if (!page) |
|
return -ENOMEM; |
|
|
|
err = ext2_prepare_chunk(page, 0, chunk_size); |
|
if (err) { |
|
unlock_page(page); |
|
goto fail; |
|
} |
|
kaddr = kmap_atomic(page); |
|
memset(kaddr, 0, chunk_size); |
|
de = (struct ext2_dir_entry_2 *)kaddr; |
|
de->name_len = 1; |
|
de->rec_len = ext2_rec_len_to_disk(EXT2_DIR_REC_LEN(1)); |
|
memcpy (de->name, ".\0\0", 4); |
|
de->inode = cpu_to_le32(inode->i_ino); |
|
ext2_set_de_type (de, inode); |
|
|
|
de = (struct ext2_dir_entry_2 *)(kaddr + EXT2_DIR_REC_LEN(1)); |
|
de->name_len = 2; |
|
de->rec_len = ext2_rec_len_to_disk(chunk_size - EXT2_DIR_REC_LEN(1)); |
|
de->inode = cpu_to_le32(parent->i_ino); |
|
memcpy (de->name, "..\0", 4); |
|
ext2_set_de_type (de, inode); |
|
kunmap_atomic(kaddr); |
|
err = ext2_commit_chunk(page, 0, chunk_size); |
|
fail: |
|
put_page(page); |
|
return err; |
|
} |
|
|
|
/* |
|
* routine to check that the specified directory is empty (for rmdir) |
|
*/ |
|
int ext2_empty_dir (struct inode * inode) |
|
{ |
|
void *page_addr = NULL; |
|
struct page *page = NULL; |
|
unsigned long i, npages = dir_pages(inode); |
|
int dir_has_error = 0; |
|
|
|
for (i = 0; i < npages; i++) { |
|
char *kaddr; |
|
ext2_dirent * de; |
|
page = ext2_get_page(inode, i, dir_has_error, &page_addr); |
|
|
|
if (IS_ERR(page)) { |
|
dir_has_error = 1; |
|
continue; |
|
} |
|
|
|
kaddr = page_addr; |
|
de = (ext2_dirent *)kaddr; |
|
kaddr += ext2_last_byte(inode, i) - EXT2_DIR_REC_LEN(1); |
|
|
|
while ((char *)de <= kaddr) { |
|
if (de->rec_len == 0) { |
|
ext2_error(inode->i_sb, __func__, |
|
"zero-length directory entry"); |
|
printk("kaddr=%p, de=%p\n", 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_le32(inode->i_ino)) |
|
goto not_empty; |
|
} else if (de->name[1] != '.') |
|
goto not_empty; |
|
} |
|
de = ext2_next_entry(de); |
|
} |
|
ext2_put_page(page, page_addr); |
|
} |
|
return 1; |
|
|
|
not_empty: |
|
ext2_put_page(page, page_addr); |
|
return 0; |
|
} |
|
|
|
const struct file_operations ext2_dir_operations = { |
|
.llseek = generic_file_llseek, |
|
.read = generic_read_dir, |
|
.iterate_shared = ext2_readdir, |
|
.unlocked_ioctl = ext2_ioctl, |
|
#ifdef CONFIG_COMPAT |
|
.compat_ioctl = ext2_compat_ioctl, |
|
#endif |
|
.fsync = ext2_fsync, |
|
};
|
|
|