1b2441318SGreg Kroah-Hartman // SPDX-License-Identifier: GPL-2.0
21da177e4SLinus Torvalds /*
31da177e4SLinus Torvalds * linux/fs/ext2/dir.c
41da177e4SLinus Torvalds *
51da177e4SLinus Torvalds * Copyright (C) 1992, 1993, 1994, 1995
61da177e4SLinus Torvalds * Remy Card (card@masi.ibp.fr)
71da177e4SLinus Torvalds * Laboratoire MASI - Institut Blaise Pascal
81da177e4SLinus Torvalds * Universite Pierre et Marie Curie (Paris VI)
91da177e4SLinus Torvalds *
101da177e4SLinus Torvalds * from
111da177e4SLinus Torvalds *
121da177e4SLinus Torvalds * linux/fs/minix/dir.c
131da177e4SLinus Torvalds *
141da177e4SLinus Torvalds * Copyright (C) 1991, 1992 Linus Torvalds
151da177e4SLinus Torvalds *
161da177e4SLinus Torvalds * ext2 directory handling functions
171da177e4SLinus Torvalds *
181da177e4SLinus Torvalds * Big-endian to little-endian byte-swapping/bitmaps by
191da177e4SLinus Torvalds * David S. Miller (davem@caip.rutgers.edu), 1995
201da177e4SLinus Torvalds *
211da177e4SLinus Torvalds * All code that works with directory layout had been switched to pagecache
221da177e4SLinus Torvalds * and moved here. AV
231da177e4SLinus Torvalds */
241da177e4SLinus Torvalds
251da177e4SLinus Torvalds #include "ext2.h"
26f34fb6ecSNick Piggin #include <linux/buffer_head.h>
271da177e4SLinus Torvalds #include <linux/pagemap.h>
28f34fb6ecSNick Piggin #include <linux/swap.h>
29e1d747d9SJeff Layton #include <linux/iversion.h>
301da177e4SLinus Torvalds
311da177e4SLinus Torvalds typedef struct ext2_dir_entry_2 ext2_dirent;
321da177e4SLinus Torvalds
3340a063f6SEric Sandeen /*
3440a063f6SEric Sandeen * Tests against MAX_REC_LEN etc were put in place for 64k block
3540a063f6SEric Sandeen * sizes; if that is not possible on this arch, we can skip
3640a063f6SEric Sandeen * those tests and speed things up.
3740a063f6SEric Sandeen */
ext2_rec_len_from_disk(__le16 dlen)3889910cccSJan Kara static inline unsigned ext2_rec_len_from_disk(__le16 dlen)
3989910cccSJan Kara {
4089910cccSJan Kara unsigned len = le16_to_cpu(dlen);
4189910cccSJan Kara
42ea1754a0SKirill A. Shutemov #if (PAGE_SIZE >= 65536)
4389910cccSJan Kara if (len == EXT2_MAX_REC_LEN)
4489910cccSJan Kara return 1 << 16;
4540a063f6SEric Sandeen #endif
4689910cccSJan Kara return len;
4789910cccSJan Kara }
4889910cccSJan Kara
ext2_rec_len_to_disk(unsigned len)4989910cccSJan Kara static inline __le16 ext2_rec_len_to_disk(unsigned len)
5089910cccSJan Kara {
51ea1754a0SKirill A. Shutemov #if (PAGE_SIZE >= 65536)
5289910cccSJan Kara if (len == (1 << 16))
5389910cccSJan Kara return cpu_to_le16(EXT2_MAX_REC_LEN);
542c11619aSJulia Lawall else
552c11619aSJulia Lawall BUG_ON(len > (1 << 16));
5640a063f6SEric Sandeen #endif
5789910cccSJan Kara return cpu_to_le16(len);
5889910cccSJan Kara }
5989910cccSJan Kara
601da177e4SLinus Torvalds /*
611da177e4SLinus Torvalds * ext2 uses block-sized chunks. Arguably, sector-sized ones would be
621da177e4SLinus Torvalds * more robust, but we have what we have
631da177e4SLinus Torvalds */
ext2_chunk_size(struct inode * inode)641da177e4SLinus Torvalds static inline unsigned ext2_chunk_size(struct inode *inode)
651da177e4SLinus Torvalds {
661da177e4SLinus Torvalds return inode->i_sb->s_blocksize;
671da177e4SLinus Torvalds }
681da177e4SLinus Torvalds
691da177e4SLinus Torvalds /*
701da177e4SLinus Torvalds * Return the offset into page `page_nr' of the last valid
711da177e4SLinus Torvalds * byte in that page, plus one.
721da177e4SLinus Torvalds */
731da177e4SLinus Torvalds static unsigned
ext2_last_byte(struct inode * inode,unsigned long page_nr)741da177e4SLinus Torvalds ext2_last_byte(struct inode *inode, unsigned long page_nr)
751da177e4SLinus Torvalds {
761da177e4SLinus Torvalds unsigned last_byte = inode->i_size;
771da177e4SLinus Torvalds
7809cbfeafSKirill A. Shutemov last_byte -= page_nr << PAGE_SHIFT;
7909cbfeafSKirill A. Shutemov if (last_byte > PAGE_SIZE)
8009cbfeafSKirill A. Shutemov last_byte = PAGE_SIZE;
811da177e4SLinus Torvalds return last_byte;
821da177e4SLinus Torvalds }
831da177e4SLinus Torvalds
ext2_commit_chunk(struct page * page,loff_t pos,unsigned len)84bc943f48SJan Kara static void ext2_commit_chunk(struct page *page, loff_t pos, unsigned len)
851da177e4SLinus Torvalds {
86f34fb6ecSNick Piggin struct address_space *mapping = page->mapping;
87f34fb6ecSNick Piggin struct inode *dir = mapping->host;
88f34fb6ecSNick Piggin
89e1d747d9SJeff Layton inode_inc_iversion(dir);
90f34fb6ecSNick Piggin block_write_end(NULL, mapping, pos, len, len, page, NULL);
91f34fb6ecSNick Piggin
92f34fb6ecSNick Piggin if (pos+len > dir->i_size) {
93f34fb6ecSNick Piggin i_size_write(dir, pos+len);
94f34fb6ecSNick Piggin mark_inode_dirty(dir);
95f34fb6ecSNick Piggin }
961da177e4SLinus Torvalds unlock_page(page);
976b7021efSJan Kara }
98f34fb6ecSNick Piggin
ext2_check_page(struct page * page,int quiet,char * kaddr)99728d392fSJavier Pello static bool ext2_check_page(struct page *page, int quiet, char *kaddr)
1001da177e4SLinus Torvalds {
1011da177e4SLinus Torvalds struct inode *dir = page->mapping->host;
1021da177e4SLinus Torvalds struct super_block *sb = dir->i_sb;
1031da177e4SLinus Torvalds unsigned chunk_size = ext2_chunk_size(dir);
1041da177e4SLinus Torvalds u32 max_inumber = le32_to_cpu(EXT2_SB(sb)->s_es->s_inodes_count);
1051da177e4SLinus Torvalds unsigned offs, rec_len;
10609cbfeafSKirill A. Shutemov unsigned limit = PAGE_SIZE;
1071da177e4SLinus Torvalds ext2_dirent *p;
1081da177e4SLinus Torvalds char *error;
1091da177e4SLinus Torvalds
11009cbfeafSKirill A. Shutemov if ((dir->i_size >> PAGE_SHIFT) == page->index) {
11109cbfeafSKirill A. Shutemov limit = dir->i_size & ~PAGE_MASK;
1121da177e4SLinus Torvalds if (limit & (chunk_size - 1))
1131da177e4SLinus Torvalds goto Ebadsize;
1141da177e4SLinus Torvalds if (!limit)
1151da177e4SLinus Torvalds goto out;
1161da177e4SLinus Torvalds }
1171da177e4SLinus Torvalds for (offs = 0; offs <= limit - EXT2_DIR_REC_LEN(1); offs += rec_len) {
1181da177e4SLinus Torvalds p = (ext2_dirent *)(kaddr + offs);
11989910cccSJan Kara rec_len = ext2_rec_len_from_disk(p->rec_len);
1201da177e4SLinus Torvalds
12140a063f6SEric Sandeen if (unlikely(rec_len < EXT2_DIR_REC_LEN(1)))
1221da177e4SLinus Torvalds goto Eshort;
12340a063f6SEric Sandeen if (unlikely(rec_len & 3))
1241da177e4SLinus Torvalds goto Ealign;
12540a063f6SEric Sandeen if (unlikely(rec_len < EXT2_DIR_REC_LEN(p->name_len)))
1261da177e4SLinus Torvalds goto Enamelen;
12740a063f6SEric Sandeen if (unlikely(((offs + rec_len - 1) ^ offs) & ~(chunk_size-1)))
1281da177e4SLinus Torvalds goto Espan;
12940a063f6SEric Sandeen if (unlikely(le32_to_cpu(p->inode) > max_inumber))
1301da177e4SLinus Torvalds goto Einumber;
1311da177e4SLinus Torvalds }
1321da177e4SLinus Torvalds if (offs != limit)
1331da177e4SLinus Torvalds goto Eend;
1341da177e4SLinus Torvalds out:
1351da177e4SLinus Torvalds SetPageChecked(page);
136be5b82dbSAl Viro return true;
1371da177e4SLinus Torvalds
1381da177e4SLinus Torvalds /* Too bad, we had an error */
1391da177e4SLinus Torvalds
1401da177e4SLinus Torvalds Ebadsize:
141bd39597cSEric Sandeen if (!quiet)
142bd39597cSEric Sandeen ext2_error(sb, __func__,
143bd39597cSEric Sandeen "size of directory #%lu is not a multiple "
144bd39597cSEric Sandeen "of chunk size", dir->i_ino);
1451da177e4SLinus Torvalds goto fail;
1461da177e4SLinus Torvalds Eshort:
1471da177e4SLinus Torvalds error = "rec_len is smaller than minimal";
1481da177e4SLinus Torvalds goto bad_entry;
1491da177e4SLinus Torvalds Ealign:
1501da177e4SLinus Torvalds error = "unaligned directory entry";
1511da177e4SLinus Torvalds goto bad_entry;
1521da177e4SLinus Torvalds Enamelen:
1531da177e4SLinus Torvalds error = "rec_len is too small for name_len";
1541da177e4SLinus Torvalds goto bad_entry;
1551da177e4SLinus Torvalds Espan:
1561da177e4SLinus Torvalds error = "directory entry across blocks";
1571da177e4SLinus Torvalds goto bad_entry;
1581da177e4SLinus Torvalds Einumber:
1591da177e4SLinus Torvalds error = "inode out of bounds";
1601da177e4SLinus Torvalds bad_entry:
161bd39597cSEric Sandeen if (!quiet)
162bd39597cSEric Sandeen ext2_error(sb, __func__, "bad entry in directory #%lu: : %s - "
1631da177e4SLinus Torvalds "offset=%lu, inode=%lu, rec_len=%d, name_len=%d",
16409cbfeafSKirill A. Shutemov dir->i_ino, error, (page->index<<PAGE_SHIFT)+offs,
1651da177e4SLinus Torvalds (unsigned long) le32_to_cpu(p->inode),
1661da177e4SLinus Torvalds rec_len, p->name_len);
1671da177e4SLinus Torvalds goto fail;
1681da177e4SLinus Torvalds Eend:
169bd39597cSEric Sandeen if (!quiet) {
1701da177e4SLinus Torvalds p = (ext2_dirent *)(kaddr + offs);
1711da177e4SLinus Torvalds ext2_error(sb, "ext2_check_page",
1721da177e4SLinus Torvalds "entry in directory #%lu spans the page boundary"
1731da177e4SLinus Torvalds "offset=%lu, inode=%lu",
17409cbfeafSKirill A. Shutemov dir->i_ino, (page->index<<PAGE_SHIFT)+offs,
1751da177e4SLinus Torvalds (unsigned long) le32_to_cpu(p->inode));
176bd39597cSEric Sandeen }
1771da177e4SLinus Torvalds fail:
1781da177e4SLinus Torvalds SetPageError(page);
179be5b82dbSAl Viro return false;
1801da177e4SLinus Torvalds }
1811da177e4SLinus Torvalds
182782b76d7SIra Weiny /*
183782b76d7SIra Weiny * Calls to ext2_get_page()/ext2_put_page() must be nested according to the
184782b76d7SIra Weiny * rules documented in kmap_local_page()/kunmap_local().
185782b76d7SIra Weiny *
186782b76d7SIra Weiny * NOTE: ext2_find_entry() and ext2_dotdot() act as a call to ext2_get_page()
187782b76d7SIra Weiny * and should be treated as a call to ext2_get_page() for nesting purposes.
188782b76d7SIra Weiny */
ext2_get_page(struct inode * dir,unsigned long n,int quiet,struct page ** page)18946022375SAl Viro static void *ext2_get_page(struct inode *dir, unsigned long n,
19046022375SAl Viro int quiet, struct page **page)
1911da177e4SLinus Torvalds {
1921da177e4SLinus Torvalds struct address_space *mapping = dir->i_mapping;
19337ce0b31SMatthew Wilcox (Oracle) struct folio *folio = read_mapping_folio(mapping, n, NULL);
19446022375SAl Viro void *page_addr;
19537ce0b31SMatthew Wilcox (Oracle)
19637ce0b31SMatthew Wilcox (Oracle) if (IS_ERR(folio))
19746022375SAl Viro return ERR_CAST(folio);
19846022375SAl Viro page_addr = kmap_local_folio(folio, n & (folio_nr_pages(folio) - 1));
19937ce0b31SMatthew Wilcox (Oracle) if (unlikely(!folio_test_checked(folio))) {
20046022375SAl Viro if (!ext2_check_page(&folio->page, quiet, page_addr))
2011da177e4SLinus Torvalds goto fail;
2021da177e4SLinus Torvalds }
20346022375SAl Viro *page = &folio->page;
20446022375SAl Viro return page_addr;
2051da177e4SLinus Torvalds
2061da177e4SLinus Torvalds fail:
20746022375SAl Viro ext2_put_page(&folio->page, page_addr);
2081da177e4SLinus Torvalds return ERR_PTR(-EIO);
2091da177e4SLinus Torvalds }
2101da177e4SLinus Torvalds
2111da177e4SLinus Torvalds /*
2121da177e4SLinus Torvalds * NOTE! unlike strncmp, ext2_match returns 1 for success, 0 for failure.
2131da177e4SLinus Torvalds *
2141da177e4SLinus Torvalds * len <= EXT2_NAME_LEN and de != NULL are guaranteed by caller.
2151da177e4SLinus Torvalds */
ext2_match(int len,const char * const name,struct ext2_dir_entry_2 * de)2161da177e4SLinus Torvalds static inline int ext2_match (int len, const char * const name,
2171da177e4SLinus Torvalds struct ext2_dir_entry_2 * de)
2181da177e4SLinus Torvalds {
2191da177e4SLinus Torvalds if (len != de->name_len)
2201da177e4SLinus Torvalds return 0;
2211da177e4SLinus Torvalds if (!de->inode)
2221da177e4SLinus Torvalds return 0;
2231da177e4SLinus Torvalds return !memcmp(name, de->name, len);
2241da177e4SLinus Torvalds }
2251da177e4SLinus Torvalds
2261da177e4SLinus Torvalds /*
2271da177e4SLinus Torvalds * p is at least 6 bytes before the end of page
2281da177e4SLinus Torvalds */
ext2_next_entry(ext2_dirent * p)2291da177e4SLinus Torvalds static inline ext2_dirent *ext2_next_entry(ext2_dirent *p)
2301da177e4SLinus Torvalds {
23189910cccSJan Kara return (ext2_dirent *)((char *)p +
23289910cccSJan Kara ext2_rec_len_from_disk(p->rec_len));
2331da177e4SLinus Torvalds }
2341da177e4SLinus Torvalds
2351da177e4SLinus Torvalds static inline unsigned
ext2_validate_entry(char * base,unsigned offset,unsigned mask)2361da177e4SLinus Torvalds ext2_validate_entry(char *base, unsigned offset, unsigned mask)
2371da177e4SLinus Torvalds {
2381da177e4SLinus Torvalds ext2_dirent *de = (ext2_dirent*)(base + offset);
2391da177e4SLinus Torvalds ext2_dirent *p = (ext2_dirent*)(base + (offset&mask));
2401da177e4SLinus Torvalds while ((char*)p < (char*)de) {
2411da177e4SLinus Torvalds if (p->rec_len == 0)
2421da177e4SLinus Torvalds break;
2431da177e4SLinus Torvalds p = ext2_next_entry(p);
2441da177e4SLinus Torvalds }
24586008392SAl Viro return offset_in_page(p);
2461da177e4SLinus Torvalds }
2471da177e4SLinus Torvalds
ext2_set_de_type(ext2_dirent * de,struct inode * inode)2481da177e4SLinus Torvalds static inline void ext2_set_de_type(ext2_dirent *de, struct inode *inode)
2491da177e4SLinus Torvalds {
2501da177e4SLinus Torvalds if (EXT2_HAS_INCOMPAT_FEATURE(inode->i_sb, EXT2_FEATURE_INCOMPAT_FILETYPE))
251e1089218SPhillip Potter de->file_type = fs_umode_to_ftype(inode->i_mode);
2521da177e4SLinus Torvalds else
2531da177e4SLinus Torvalds de->file_type = 0;
2541da177e4SLinus Torvalds }
2551da177e4SLinus Torvalds
2561da177e4SLinus Torvalds static int
ext2_readdir(struct file * file,struct dir_context * ctx)25780886298SAl Viro ext2_readdir(struct file *file, struct dir_context *ctx)
2581da177e4SLinus Torvalds {
25980886298SAl Viro loff_t pos = ctx->pos;
26080886298SAl Viro struct inode *inode = file_inode(file);
2611da177e4SLinus Torvalds struct super_block *sb = inode->i_sb;
26209cbfeafSKirill A. Shutemov unsigned int offset = pos & ~PAGE_MASK;
26309cbfeafSKirill A. Shutemov unsigned long n = pos >> PAGE_SHIFT;
2641da177e4SLinus Torvalds unsigned long npages = dir_pages(inode);
2651da177e4SLinus Torvalds unsigned chunk_mask = ~(ext2_chunk_size(inode)-1);
266c472c07bSGoffredo Baroncelli bool need_revalidate = !inode_eq_iversion(inode, file->f_version);
267e1089218SPhillip Potter bool has_filetype;
2681da177e4SLinus Torvalds
2691da177e4SLinus Torvalds if (pos > inode->i_size - EXT2_DIR_REC_LEN(1))
2702d7f2ea9SAl Viro return 0;
2711da177e4SLinus Torvalds
272e1089218SPhillip Potter has_filetype =
273e1089218SPhillip Potter EXT2_HAS_INCOMPAT_FEATURE(sb, EXT2_FEATURE_INCOMPAT_FILETYPE);
2741da177e4SLinus Torvalds
2751da177e4SLinus Torvalds for ( ; n < npages; n++, offset = 0) {
2761da177e4SLinus Torvalds ext2_dirent *de;
27746022375SAl Viro struct page *page;
27846022375SAl Viro char *kaddr = ext2_get_page(inode, n, 0, &page);
27946022375SAl Viro char *limit;
2801da177e4SLinus Torvalds
28146022375SAl Viro if (IS_ERR(kaddr)) {
282605afd60SHarvey Harrison ext2_error(sb, __func__,
2831da177e4SLinus Torvalds "bad page in #%lu",
2841da177e4SLinus Torvalds inode->i_ino);
28509cbfeafSKirill A. Shutemov ctx->pos += PAGE_SIZE - offset;
28646022375SAl Viro return PTR_ERR(kaddr);
2871da177e4SLinus Torvalds }
2882d7f2ea9SAl Viro if (unlikely(need_revalidate)) {
2892d7f2ea9SAl Viro if (offset) {
2901da177e4SLinus Torvalds offset = ext2_validate_entry(kaddr, offset, chunk_mask);
29109cbfeafSKirill A. Shutemov ctx->pos = (n<<PAGE_SHIFT) + offset;
2922d7f2ea9SAl Viro }
293e1d747d9SJeff Layton file->f_version = inode_query_iversion(inode);
294e1d747d9SJeff Layton need_revalidate = false;
2951da177e4SLinus Torvalds }
2961da177e4SLinus Torvalds de = (ext2_dirent *)(kaddr+offset);
2971da177e4SLinus Torvalds limit = kaddr + ext2_last_byte(inode, n) - EXT2_DIR_REC_LEN(1);
2981da177e4SLinus Torvalds for ( ;(char*)de <= limit; de = ext2_next_entry(de)) {
2991da177e4SLinus Torvalds if (de->rec_len == 0) {
300605afd60SHarvey Harrison ext2_error(sb, __func__,
3011da177e4SLinus Torvalds "zero-length directory entry");
30291f646fbSAl Viro ext2_put_page(page, de);
3032d7f2ea9SAl Viro return -EIO;
3041da177e4SLinus Torvalds }
3051da177e4SLinus Torvalds if (de->inode) {
3061da177e4SLinus Torvalds unsigned char d_type = DT_UNKNOWN;
3071da177e4SLinus Torvalds
308e1089218SPhillip Potter if (has_filetype)
309e1089218SPhillip Potter d_type = fs_ftype_to_dtype(de->file_type);
3101da177e4SLinus Torvalds
31180886298SAl Viro if (!dir_emit(ctx, de->name, de->name_len,
31280886298SAl Viro le32_to_cpu(de->inode),
31380886298SAl Viro d_type)) {
31491f646fbSAl Viro ext2_put_page(page, de);
3152d7f2ea9SAl Viro return 0;
3161da177e4SLinus Torvalds }
3171da177e4SLinus Torvalds }
31880886298SAl Viro ctx->pos += ext2_rec_len_from_disk(de->rec_len);
3191da177e4SLinus Torvalds }
320782b76d7SIra Weiny ext2_put_page(page, kaddr);
3211da177e4SLinus Torvalds }
3222d7f2ea9SAl Viro return 0;
3231da177e4SLinus Torvalds }
3241da177e4SLinus Torvalds
3251da177e4SLinus Torvalds /*
3261da177e4SLinus Torvalds * ext2_find_entry()
3271da177e4SLinus Torvalds *
3281da177e4SLinus Torvalds * finds an entry in the specified directory with the wanted name. It
32992e12888SJérémy Cochoy * returns the page in which the entry was found (as a parameter - res_page),
33092e12888SJérémy Cochoy * and the entry itself. Page is returned mapped and unlocked.
3311da177e4SLinus Torvalds * Entry is guaranteed to be valid.
332a6fbd0abSIra Weiny *
333a6fbd0abSIra Weiny * On Success ext2_put_page() should be called on *res_page.
334782b76d7SIra Weiny *
335782b76d7SIra Weiny * NOTE: Calls to ext2_get_page()/ext2_put_page() must be nested according to
336782b76d7SIra Weiny * the rules documented in kmap_local_page()/kunmap_local().
337782b76d7SIra Weiny *
338782b76d7SIra Weiny * ext2_find_entry() and ext2_dotdot() act as a call to ext2_get_page() and
339782b76d7SIra Weiny * should be treated as a call to ext2_get_page() for nesting purposes.
3401da177e4SLinus Torvalds */
ext2_find_entry(struct inode * dir,const struct qstr * child,struct page ** res_page)3411da177e4SLinus Torvalds struct ext2_dir_entry_2 *ext2_find_entry (struct inode *dir,
342b8b9e8b3SAl Viro const struct qstr *child, struct page **res_page)
3431da177e4SLinus Torvalds {
344a9885444SAl Viro const char *name = child->name;
345a9885444SAl Viro int namelen = child->len;
3461da177e4SLinus Torvalds unsigned reclen = EXT2_DIR_REC_LEN(namelen);
3471da177e4SLinus Torvalds unsigned long start, n;
3481da177e4SLinus Torvalds unsigned long npages = dir_pages(dir);
3491da177e4SLinus Torvalds struct page *page = NULL;
3501da177e4SLinus Torvalds struct ext2_inode_info *ei = EXT2_I(dir);
3511da177e4SLinus Torvalds ext2_dirent * de;
3521da177e4SLinus Torvalds
3531da177e4SLinus Torvalds if (npages == 0)
3541da177e4SLinus Torvalds goto out;
3551da177e4SLinus Torvalds
3561da177e4SLinus Torvalds /* OFFSET_CACHE */
3571da177e4SLinus Torvalds *res_page = NULL;
3581da177e4SLinus Torvalds
3591da177e4SLinus Torvalds start = ei->i_dir_start_lookup;
3601da177e4SLinus Torvalds if (start >= npages)
3611da177e4SLinus Torvalds start = 0;
3621da177e4SLinus Torvalds n = start;
3631da177e4SLinus Torvalds do {
364b8b9e8b3SAl Viro char *kaddr = ext2_get_page(dir, n, 0, &page);
365b8b9e8b3SAl Viro if (IS_ERR(kaddr))
366b8b9e8b3SAl Viro return ERR_CAST(kaddr);
36746022375SAl Viro
3681da177e4SLinus Torvalds de = (ext2_dirent *) kaddr;
3691da177e4SLinus Torvalds kaddr += ext2_last_byte(dir, n) - reclen;
3701da177e4SLinus Torvalds while ((char *) de <= kaddr) {
3711da177e4SLinus Torvalds if (de->rec_len == 0) {
372605afd60SHarvey Harrison ext2_error(dir->i_sb, __func__,
3731da177e4SLinus Torvalds "zero-length directory entry");
37491f646fbSAl Viro ext2_put_page(page, de);
3751da177e4SLinus Torvalds goto out;
3761da177e4SLinus Torvalds }
3771da177e4SLinus Torvalds if (ext2_match(namelen, name, de))
3781da177e4SLinus Torvalds goto found;
3791da177e4SLinus Torvalds de = ext2_next_entry(de);
3801da177e4SLinus Torvalds }
38191f646fbSAl Viro ext2_put_page(page, kaddr);
382bd39597cSEric Sandeen
3831da177e4SLinus Torvalds if (++n >= npages)
3841da177e4SLinus Torvalds n = 0;
385d8adb9ceSEric Sandeen /* next page is past the blocks we've got */
38609cbfeafSKirill A. Shutemov if (unlikely(n > (dir->i_blocks >> (PAGE_SHIFT - 9)))) {
387605afd60SHarvey Harrison ext2_error(dir->i_sb, __func__,
388d8adb9ceSEric Sandeen "dir %lu size %lld exceeds block count %llu",
389d8adb9ceSEric Sandeen dir->i_ino, dir->i_size,
390d8adb9ceSEric Sandeen (unsigned long long)dir->i_blocks);
391d8adb9ceSEric Sandeen goto out;
392d8adb9ceSEric Sandeen }
3931da177e4SLinus Torvalds } while (n != start);
3941da177e4SLinus Torvalds out:
395a43850a3Szhangyi (F) return ERR_PTR(-ENOENT);
3961da177e4SLinus Torvalds
3971da177e4SLinus Torvalds found:
3981da177e4SLinus Torvalds *res_page = page;
3991da177e4SLinus Torvalds ei->i_dir_start_lookup = n;
4001da177e4SLinus Torvalds return de;
4011da177e4SLinus Torvalds }
4021da177e4SLinus Torvalds
403d030bd1aSBo Liu /*
404a6fbd0abSIra Weiny * Return the '..' directory entry and the page in which the entry was found
405a6fbd0abSIra Weiny * (as a parameter - p).
406a6fbd0abSIra Weiny *
407a6fbd0abSIra Weiny * On Success ext2_put_page() should be called on *p.
408782b76d7SIra Weiny *
409782b76d7SIra Weiny * NOTE: Calls to ext2_get_page()/ext2_put_page() must be nested according to
410782b76d7SIra Weiny * the rules documented in kmap_local_page()/kunmap_local().
411782b76d7SIra Weiny *
412782b76d7SIra Weiny * ext2_find_entry() and ext2_dotdot() act as a call to ext2_get_page() and
413782b76d7SIra Weiny * should be treated as a call to ext2_get_page() for nesting purposes.
414a6fbd0abSIra Weiny */
ext2_dotdot(struct inode * dir,struct page ** p)415b8b9e8b3SAl Viro struct ext2_dir_entry_2 *ext2_dotdot(struct inode *dir, struct page **p)
4161da177e4SLinus Torvalds {
417b8b9e8b3SAl Viro ext2_dirent *de = ext2_get_page(dir, 0, 0, p);
4181da177e4SLinus Torvalds
419b8b9e8b3SAl Viro if (!IS_ERR(de))
420b8b9e8b3SAl Viro return ext2_next_entry(de);
421b8b9e8b3SAl Viro return NULL;
4221da177e4SLinus Torvalds }
4231da177e4SLinus Torvalds
ext2_inode_by_name(struct inode * dir,const struct qstr * child,ino_t * ino)424b4962091Szhangyi (F) int ext2_inode_by_name(struct inode *dir, const struct qstr *child, ino_t *ino)
4251da177e4SLinus Torvalds {
4261da177e4SLinus Torvalds struct ext2_dir_entry_2 *de;
4271da177e4SLinus Torvalds struct page *page;
4281da177e4SLinus Torvalds
429b8b9e8b3SAl Viro de = ext2_find_entry(dir, child, &page);
430a43850a3Szhangyi (F) if (IS_ERR(de))
431b4962091Szhangyi (F) return PTR_ERR(de);
432b4962091Szhangyi (F)
433b4962091Szhangyi (F) *ino = le32_to_cpu(de->inode);
43491f646fbSAl Viro ext2_put_page(page, de);
435b4962091Szhangyi (F) return 0;
4361da177e4SLinus Torvalds }
4371da177e4SLinus Torvalds
ext2_prepare_chunk(struct page * page,loff_t pos,unsigned len)438f4e420dcSChristoph Hellwig static int ext2_prepare_chunk(struct page *page, loff_t pos, unsigned len)
439f4e420dcSChristoph Hellwig {
4406e1db88dSChristoph Hellwig return __block_write_begin(page, pos, len, ext2_get_block);
441f4e420dcSChristoph Hellwig }
442f4e420dcSChristoph Hellwig
443bc943f48SJan Kara
ext2_handle_dirsync(struct inode * dir)444bc943f48SJan Kara static int ext2_handle_dirsync(struct inode *dir)
445bc943f48SJan Kara {
446bc943f48SJan Kara int err;
447bc943f48SJan Kara
448bc943f48SJan Kara err = filemap_write_and_wait(dir->i_mapping);
449bc943f48SJan Kara if (!err)
450bc943f48SJan Kara err = sync_inode_metadata(dir, 1);
451bc943f48SJan Kara return err;
452bc943f48SJan Kara }
453bc943f48SJan Kara
ext2_set_link(struct inode * dir,struct ext2_dir_entry_2 * de,struct page * page,struct inode * inode,bool update_times)4547a5fa171SChristoph Hellwig int ext2_set_link(struct inode *dir, struct ext2_dir_entry_2 *de,
455dae42837SAl Viro struct page *page, struct inode *inode, bool update_times)
4561da177e4SLinus Torvalds {
45786008392SAl Viro loff_t pos = page_offset(page) + offset_in_page(de);
45889910cccSJan Kara unsigned len = ext2_rec_len_from_disk(de->rec_len);
4591da177e4SLinus Torvalds int err;
4601da177e4SLinus Torvalds
4611da177e4SLinus Torvalds lock_page(page);
462f4e420dcSChristoph Hellwig err = ext2_prepare_chunk(page, pos, len);
4637a5fa171SChristoph Hellwig if (err) {
4647a5fa171SChristoph Hellwig unlock_page(page);
4657a5fa171SChristoph Hellwig return err;
4667a5fa171SChristoph Hellwig }
4671da177e4SLinus Torvalds de->inode = cpu_to_le32(inode->i_ino);
4681da177e4SLinus Torvalds ext2_set_de_type(de, inode);
469bc943f48SJan Kara ext2_commit_chunk(page, pos, len);
47039fe7557SJan Kara if (update_times)
471*fc4eed64SJeff Layton dir->i_mtime = inode_set_ctime_current(dir);
4721da177e4SLinus Torvalds EXT2_I(dir)->i_flags &= ~EXT2_BTREE_FL;
4731da177e4SLinus Torvalds mark_inode_dirty(dir);
4747a5fa171SChristoph Hellwig return ext2_handle_dirsync(dir);
4751da177e4SLinus Torvalds }
4761da177e4SLinus Torvalds
4771da177e4SLinus Torvalds /*
4781da177e4SLinus Torvalds * Parent is locked.
4791da177e4SLinus Torvalds */
ext2_add_link(struct dentry * dentry,struct inode * inode)4801da177e4SLinus Torvalds int ext2_add_link (struct dentry *dentry, struct inode *inode)
4811da177e4SLinus Torvalds {
4822b0143b5SDavid Howells struct inode *dir = d_inode(dentry->d_parent);
4831da177e4SLinus Torvalds const char *name = dentry->d_name.name;
4841da177e4SLinus Torvalds int namelen = dentry->d_name.len;
4851da177e4SLinus Torvalds unsigned chunk_size = ext2_chunk_size(dir);
4861da177e4SLinus Torvalds unsigned reclen = EXT2_DIR_REC_LEN(namelen);
4871da177e4SLinus Torvalds unsigned short rec_len, name_len;
4881da177e4SLinus Torvalds struct page *page = NULL;
4891da177e4SLinus Torvalds ext2_dirent * de;
4901da177e4SLinus Torvalds unsigned long npages = dir_pages(dir);
4911da177e4SLinus Torvalds unsigned long n;
492f34fb6ecSNick Piggin loff_t pos;
4931da177e4SLinus Torvalds int err;
4941da177e4SLinus Torvalds
4951da177e4SLinus Torvalds /*
4961da177e4SLinus Torvalds * We take care of directory expansion in the same loop.
4971da177e4SLinus Torvalds * This code plays outside i_size, so it locks the page
4981da177e4SLinus Torvalds * to protect that region.
4991da177e4SLinus Torvalds */
5001da177e4SLinus Torvalds for (n = 0; n <= npages; n++) {
501b8b9e8b3SAl Viro char *kaddr = ext2_get_page(dir, n, 0, &page);
5021da177e4SLinus Torvalds char *dir_end;
5031da177e4SLinus Torvalds
50491f646fbSAl Viro if (IS_ERR(kaddr))
50591f646fbSAl Viro return PTR_ERR(kaddr);
5061da177e4SLinus Torvalds lock_page(page);
5071da177e4SLinus Torvalds dir_end = kaddr + ext2_last_byte(dir, n);
5081da177e4SLinus Torvalds de = (ext2_dirent *)kaddr;
50909cbfeafSKirill A. Shutemov kaddr += PAGE_SIZE - reclen;
5101da177e4SLinus Torvalds while ((char *)de <= kaddr) {
5111da177e4SLinus Torvalds if ((char *)de == dir_end) {
5121da177e4SLinus Torvalds /* We hit i_size */
5131da177e4SLinus Torvalds name_len = 0;
5141da177e4SLinus Torvalds rec_len = chunk_size;
51589910cccSJan Kara de->rec_len = ext2_rec_len_to_disk(chunk_size);
5161da177e4SLinus Torvalds de->inode = 0;
5171da177e4SLinus Torvalds goto got_it;
5181da177e4SLinus Torvalds }
5191da177e4SLinus Torvalds if (de->rec_len == 0) {
520605afd60SHarvey Harrison ext2_error(dir->i_sb, __func__,
5211da177e4SLinus Torvalds "zero-length directory entry");
5221da177e4SLinus Torvalds err = -EIO;
5231da177e4SLinus Torvalds goto out_unlock;
5241da177e4SLinus Torvalds }
5251da177e4SLinus Torvalds err = -EEXIST;
5261da177e4SLinus Torvalds if (ext2_match (namelen, name, de))
5271da177e4SLinus Torvalds goto out_unlock;
5281da177e4SLinus Torvalds name_len = EXT2_DIR_REC_LEN(de->name_len);
52989910cccSJan Kara rec_len = ext2_rec_len_from_disk(de->rec_len);
5301da177e4SLinus Torvalds if (!de->inode && rec_len >= reclen)
5311da177e4SLinus Torvalds goto got_it;
5321da177e4SLinus Torvalds if (rec_len >= name_len + reclen)
5331da177e4SLinus Torvalds goto got_it;
5341da177e4SLinus Torvalds de = (ext2_dirent *) ((char *) de + rec_len);
5351da177e4SLinus Torvalds }
5361da177e4SLinus Torvalds unlock_page(page);
53791f646fbSAl Viro ext2_put_page(page, kaddr);
5381da177e4SLinus Torvalds }
5391da177e4SLinus Torvalds BUG();
5401da177e4SLinus Torvalds return -EINVAL;
5411da177e4SLinus Torvalds
5421da177e4SLinus Torvalds got_it:
54386008392SAl Viro pos = page_offset(page) + offset_in_page(de);
544f4e420dcSChristoph Hellwig err = ext2_prepare_chunk(page, pos, rec_len);
5451da177e4SLinus Torvalds if (err)
5461da177e4SLinus Torvalds goto out_unlock;
5471da177e4SLinus Torvalds if (de->inode) {
5481da177e4SLinus Torvalds ext2_dirent *de1 = (ext2_dirent *) ((char *) de + name_len);
54989910cccSJan Kara de1->rec_len = ext2_rec_len_to_disk(rec_len - name_len);
55089910cccSJan Kara de->rec_len = ext2_rec_len_to_disk(name_len);
5511da177e4SLinus Torvalds de = de1;
5521da177e4SLinus Torvalds }
5531da177e4SLinus Torvalds de->name_len = namelen;
5541da177e4SLinus Torvalds memcpy(de->name, name, namelen);
5551da177e4SLinus Torvalds de->inode = cpu_to_le32(inode->i_ino);
5561da177e4SLinus Torvalds ext2_set_de_type (de, inode);
557bc943f48SJan Kara ext2_commit_chunk(page, pos, rec_len);
558*fc4eed64SJeff Layton dir->i_mtime = inode_set_ctime_current(dir);
5591da177e4SLinus Torvalds EXT2_I(dir)->i_flags &= ~EXT2_BTREE_FL;
5601da177e4SLinus Torvalds mark_inode_dirty(dir);
561bc943f48SJan Kara err = ext2_handle_dirsync(dir);
5621da177e4SLinus Torvalds /* OFFSET_CACHE */
5631da177e4SLinus Torvalds out_put:
56491f646fbSAl Viro ext2_put_page(page, de);
5651da177e4SLinus Torvalds return err;
5661da177e4SLinus Torvalds out_unlock:
5671da177e4SLinus Torvalds unlock_page(page);
5681da177e4SLinus Torvalds goto out_put;
5691da177e4SLinus Torvalds }
5701da177e4SLinus Torvalds
5711da177e4SLinus Torvalds /*
5721da177e4SLinus Torvalds * ext2_delete_entry deletes a directory entry by merging it with the
573e2ebb123SIra Weiny * previous entry. Page is up-to-date.
5741da177e4SLinus Torvalds */
ext2_delete_entry(struct ext2_dir_entry_2 * dir,struct page * page)575dae42837SAl Viro int ext2_delete_entry(struct ext2_dir_entry_2 *dir, struct page *page)
5761da177e4SLinus Torvalds {
577f4e420dcSChristoph Hellwig struct inode *inode = page->mapping->host;
578dae42837SAl Viro char *kaddr = (char *)((unsigned long)dir & PAGE_MASK);
57986008392SAl Viro unsigned from = offset_in_page(dir) & ~(ext2_chunk_size(inode)-1);
58086008392SAl Viro unsigned to = offset_in_page(dir) +
58189910cccSJan Kara ext2_rec_len_from_disk(dir->rec_len);
582f34fb6ecSNick Piggin loff_t pos;
5831da177e4SLinus Torvalds ext2_dirent *pde = NULL;
5841da177e4SLinus Torvalds ext2_dirent *de = (ext2_dirent *)(kaddr + from);
5851da177e4SLinus Torvalds int err;
5861da177e4SLinus Torvalds
5871da177e4SLinus Torvalds while ((char*)de < (char*)dir) {
5881da177e4SLinus Torvalds if (de->rec_len == 0) {
589605afd60SHarvey Harrison ext2_error(inode->i_sb, __func__,
5901da177e4SLinus Torvalds "zero-length directory entry");
5918f1dca19SAl Viro return -EIO;
5921da177e4SLinus Torvalds }
5931da177e4SLinus Torvalds pde = de;
5941da177e4SLinus Torvalds de = ext2_next_entry(de);
5951da177e4SLinus Torvalds }
5961da177e4SLinus Torvalds if (pde)
59786008392SAl Viro from = offset_in_page(pde);
598f34fb6ecSNick Piggin pos = page_offset(page) + from;
5991da177e4SLinus Torvalds lock_page(page);
600f4e420dcSChristoph Hellwig err = ext2_prepare_chunk(page, pos, to - from);
6018f1dca19SAl Viro if (err) {
6028f1dca19SAl Viro unlock_page(page);
6038f1dca19SAl Viro return err;
6048f1dca19SAl Viro }
6051da177e4SLinus Torvalds if (pde)
60689910cccSJan Kara pde->rec_len = ext2_rec_len_to_disk(to - from);
6071da177e4SLinus Torvalds dir->inode = 0;
608bc943f48SJan Kara ext2_commit_chunk(page, pos, to - from);
609*fc4eed64SJeff Layton inode->i_mtime = inode_set_ctime_current(inode);
6101da177e4SLinus Torvalds EXT2_I(inode)->i_flags &= ~EXT2_BTREE_FL;
6111da177e4SLinus Torvalds mark_inode_dirty(inode);
6128f1dca19SAl Viro return ext2_handle_dirsync(inode);
6131da177e4SLinus Torvalds }
6141da177e4SLinus Torvalds
6151da177e4SLinus Torvalds /*
6161da177e4SLinus Torvalds * Set the first fragment of directory.
6171da177e4SLinus Torvalds */
ext2_make_empty(struct inode * inode,struct inode * parent)6181da177e4SLinus Torvalds int ext2_make_empty(struct inode *inode, struct inode *parent)
6191da177e4SLinus Torvalds {
620f4e420dcSChristoph Hellwig struct page *page = grab_cache_page(inode->i_mapping, 0);
6211da177e4SLinus Torvalds unsigned chunk_size = ext2_chunk_size(inode);
6221da177e4SLinus Torvalds struct ext2_dir_entry_2 * de;
6231da177e4SLinus Torvalds int err;
6241da177e4SLinus Torvalds void *kaddr;
6251da177e4SLinus Torvalds
6261da177e4SLinus Torvalds if (!page)
6271da177e4SLinus Torvalds return -ENOMEM;
628f34fb6ecSNick Piggin
629f4e420dcSChristoph Hellwig err = ext2_prepare_chunk(page, 0, chunk_size);
6301da177e4SLinus Torvalds if (err) {
6311da177e4SLinus Torvalds unlock_page(page);
6321da177e4SLinus Torvalds goto fail;
6331da177e4SLinus Torvalds }
63496b87cbdSFabio M. De Francesco kaddr = kmap_local_page(page);
6351da177e4SLinus Torvalds memset(kaddr, 0, chunk_size);
6361da177e4SLinus Torvalds de = (struct ext2_dir_entry_2 *)kaddr;
6371da177e4SLinus Torvalds de->name_len = 1;
63889910cccSJan Kara de->rec_len = ext2_rec_len_to_disk(EXT2_DIR_REC_LEN(1));
6391da177e4SLinus Torvalds memcpy (de->name, ".\0\0", 4);
6401da177e4SLinus Torvalds de->inode = cpu_to_le32(inode->i_ino);
6411da177e4SLinus Torvalds ext2_set_de_type (de, inode);
6421da177e4SLinus Torvalds
6431da177e4SLinus Torvalds de = (struct ext2_dir_entry_2 *)(kaddr + EXT2_DIR_REC_LEN(1));
6441da177e4SLinus Torvalds de->name_len = 2;
64589910cccSJan Kara de->rec_len = ext2_rec_len_to_disk(chunk_size - EXT2_DIR_REC_LEN(1));
6461da177e4SLinus Torvalds de->inode = cpu_to_le32(parent->i_ino);
6471da177e4SLinus Torvalds memcpy (de->name, "..\0", 4);
6481da177e4SLinus Torvalds ext2_set_de_type (de, inode);
64996b87cbdSFabio M. De Francesco kunmap_local(kaddr);
650bc943f48SJan Kara ext2_commit_chunk(page, 0, chunk_size);
651bc943f48SJan Kara err = ext2_handle_dirsync(inode);
6521da177e4SLinus Torvalds fail:
65309cbfeafSKirill A. Shutemov put_page(page);
6541da177e4SLinus Torvalds return err;
6551da177e4SLinus Torvalds }
6561da177e4SLinus Torvalds
6571da177e4SLinus Torvalds /*
6581da177e4SLinus Torvalds * routine to check that the specified directory is empty (for rmdir)
6591da177e4SLinus Torvalds */
ext2_empty_dir(struct inode * inode)6601da177e4SLinus Torvalds int ext2_empty_dir (struct inode * inode)
6611da177e4SLinus Torvalds {
66291f646fbSAl Viro struct page *page;
66391f646fbSAl Viro char *kaddr;
6641da177e4SLinus Torvalds unsigned long i, npages = dir_pages(inode);
6651da177e4SLinus Torvalds
6661da177e4SLinus Torvalds for (i = 0; i < npages; i++) {
6671da177e4SLinus Torvalds ext2_dirent *de;
6681da177e4SLinus Torvalds
66991f646fbSAl Viro kaddr = ext2_get_page(inode, i, 0, &page);
67091f646fbSAl Viro if (IS_ERR(kaddr))
67127e714c0SAl Viro return 0;
6721da177e4SLinus Torvalds
6731da177e4SLinus Torvalds de = (ext2_dirent *)kaddr;
6741da177e4SLinus Torvalds kaddr += ext2_last_byte(inode, i) - EXT2_DIR_REC_LEN(1);
6751da177e4SLinus Torvalds
6761da177e4SLinus Torvalds while ((char *)de <= kaddr) {
6771da177e4SLinus Torvalds if (de->rec_len == 0) {
678605afd60SHarvey Harrison ext2_error(inode->i_sb, __func__,
6791da177e4SLinus Torvalds "zero-length directory entry");
6801da177e4SLinus Torvalds printk("kaddr=%p, de=%p\n", kaddr, de);
6811da177e4SLinus Torvalds goto not_empty;
6821da177e4SLinus Torvalds }
6831da177e4SLinus Torvalds if (de->inode != 0) {
6841da177e4SLinus Torvalds /* check for . and .. */
6851da177e4SLinus Torvalds if (de->name[0] != '.')
6861da177e4SLinus Torvalds goto not_empty;
6871da177e4SLinus Torvalds if (de->name_len > 2)
6881da177e4SLinus Torvalds goto not_empty;
6891da177e4SLinus Torvalds if (de->name_len < 2) {
6901da177e4SLinus Torvalds if (de->inode !=
6911da177e4SLinus Torvalds cpu_to_le32(inode->i_ino))
6921da177e4SLinus Torvalds goto not_empty;
6931da177e4SLinus Torvalds } else if (de->name[1] != '.')
6941da177e4SLinus Torvalds goto not_empty;
6951da177e4SLinus Torvalds }
6961da177e4SLinus Torvalds de = ext2_next_entry(de);
6971da177e4SLinus Torvalds }
69891f646fbSAl Viro ext2_put_page(page, kaddr);
6991da177e4SLinus Torvalds }
7001da177e4SLinus Torvalds return 1;
7011da177e4SLinus Torvalds
7021da177e4SLinus Torvalds not_empty:
70391f646fbSAl Viro ext2_put_page(page, kaddr);
7041da177e4SLinus Torvalds return 0;
7051da177e4SLinus Torvalds }
7061da177e4SLinus Torvalds
7074b6f5d20SArjan van de Ven const struct file_operations ext2_dir_operations = {
7081da177e4SLinus Torvalds .llseek = generic_file_llseek,
7091da177e4SLinus Torvalds .read = generic_read_dir,
7103b0a3c1aSAl Viro .iterate_shared = ext2_readdir,
71114f9f7b2SAndi Kleen .unlocked_ioctl = ext2_ioctl,
712e322ff07SDavid Howells #ifdef CONFIG_COMPAT
713e322ff07SDavid Howells .compat_ioctl = ext2_compat_ioctl,
714e322ff07SDavid Howells #endif
71548bde86dSJan Kara .fsync = ext2_fsync,
7161da177e4SLinus Torvalds };
717