LCOV - code coverage report
Current view: top level - lkbce/fs/ext2 - dir.c (source / functions) Hit Total Coverage
Test: coverage.info Lines: 449 449 100.0 %
Date: 2017-01-25 Functions: 22 22 100.0 %

          Line data    Source code
       1             : /*
       2             :  *  linux/fs/ext2/dir.c
       3             :  *
       4             :  * Copyright (C) 1992, 1993, 1994, 1995
       5             :  * Remy Card (card@masi.ibp.fr)
       6             :  * Laboratoire MASI - Institut Blaise Pascal
       7             :  * Universite Pierre et Marie Curie (Paris VI)
       8             :  *
       9             :  *  from
      10             :  *
      11             :  *  linux/fs/minix/dir.c
      12             :  *
      13             :  *  Copyright (C) 1991, 1992  Linus Torvalds
      14             :  *
      15             :  *  ext2 directory handling functions
      16             :  *
      17             :  *  Big-endian to little-endian byte-swapping/bitmaps by
      18             :  *        David S. Miller (davem@caip.rutgers.edu), 1995
      19             :  *
      20             :  * All code that works with directory layout had been switched to pagecache
      21             :  * and moved here. AV
      22             :  */
      23             : 
      24             : #include "ext2.h"
      25             : #include <linux/buffer_head.h>
      26             : #include <linux/pagemap.h>
      27             : #include <linux/swap.h>
      28             : 
      29           1 : typedef struct ext2_dir_entry_2 ext2_dirent;
      30             : 
      31             : static inline unsigned ext2_rec_len_from_disk(__le16 dlen)
      32             : {
      33         364 :         unsigned len = le16_to_cpu(dlen);
      34             : 
      35         364 :         if (len == EXT2_MAX_REC_LEN)
      36         182 :                 return 1 << 16;
      37         182 :         return len;
      38             : }
      39             : 
      40             : static inline __le16 ext2_rec_len_to_disk(unsigned len)
      41             : {
      42         312 :         if (len == (1 << 16))
      43         104 :                 return cpu_to_le16(EXT2_MAX_REC_LEN);
      44             :         else
      45         624 :                 BUG_ON(len > (1 << 16));
      46         104 :         return cpu_to_le16(len);
      47             : }
      48             : 
      49             : /*
      50             :  * ext2 uses block-sized chunks. Arguably, sector-sized ones would be
      51             :  * more robust, but we have what we have
      52             :  */
      53             : static inline unsigned ext2_chunk_size(struct inode *inode)
      54             : {
      55         238 :         return inode->i_sb->s_blocksize;
      56             : }
      57             : 
      58             : static inline void ext2_put_page(struct page *page)
      59             : {
      60         696 :         kunmap(page);
      61         348 :         page_cache_release(page);
      62         348 : }
      63             : 
      64             : static inline unsigned long dir_pages(struct inode *inode)
      65             : {
      66         140 :         return (inode->i_size+PAGE_CACHE_SIZE-1)>>PAGE_CACHE_SHIFT;
      67             : }
      68             : 
      69             : /*
      70             :  * Return the offset into page `page_nr' of the last valid
      71             :  * byte in that page, plus one.
      72             :  */
      73             : static unsigned
      74             : ext2_last_byte(struct inode *inode, unsigned long page_nr)
      75             : {
      76         213 :         unsigned last_byte = inode->i_size;
      77             : 
      78          71 :         last_byte -= page_nr << PAGE_CACHE_SHIFT;
      79         142 :         if (last_byte > PAGE_CACHE_SIZE)
      80          71 :                 last_byte = PAGE_CACHE_SIZE;
      81          71 :         return last_byte;
      82             : }
      83             : 
      84             : static int ext2_commit_chunk(struct page *page, loff_t pos, unsigned len)
      85             : {
      86         128 :         struct address_space *mapping = page->mapping;
      87         128 :         struct inode *dir = mapping->host;
      88         128 :         int err = 0;
      89             : 
      90          64 :         dir->i_version++;
      91          64 :         block_write_end(NULL, mapping, pos, len, len, page, NULL);
      92             : 
      93         128 :         if (pos+len > dir->i_size) {
      94         128 :                 i_size_write(dir, pos+len);
      95         128 :                 mark_inode_dirty(dir);
      96             :         }
      97             : 
      98         512 :         if (IS_DIRSYNC(dir)) {
      99         128 :                 err = write_one_page(page, 1);
     100         256 :                 if (!err)
     101         256 :                         err = ext2_sync_inode(dir);
     102             :         } else {
     103         128 :                 unlock_page(page);
     104             :         }
     105             : 
     106         192 :         return err;
     107             : }
     108             : 
     109             : static void ext2_check_page(struct page *page, int quiet)
     110             : {
     111         148 :         struct inode *dir = page->mapping->host;
     112         148 :         struct super_block *sb = dir->i_sb;
     113         296 :         unsigned chunk_size = ext2_chunk_size(dir);
     114         296 :         char *kaddr = page_address(page);
     115         296 :         u32 max_inumber = le32_to_cpu(EXT2_SB(sb)->s_es->s_inodes_count);
     116          74 :         unsigned offs, rec_len;
     117         148 :         unsigned limit = PAGE_CACHE_SIZE;
     118          74 :         ext2_dirent *p;
     119          74 :         char *error;
     120          74 : 
     121         222 :         if ((dir->i_size >> PAGE_CACHE_SHIFT) == page->index) {
     122         222 :                 limit = dir->i_size & ~PAGE_CACHE_MASK;
     123         222 :                 if (limit & (chunk_size - 1))
     124          74 :                         goto Ebadsize;
     125         148 :                 if (!limit)
     126          74 :                         goto out;
     127             :         }
     128         370 :         for (offs = 0; offs <= limit - EXT2_DIR_REC_LEN(1); offs += rec_len) {
     129         222 :                 p = (ext2_dirent *)(kaddr + offs);
     130         296 :                 rec_len = ext2_rec_len_from_disk(p->rec_len);
     131             : 
     132         148 :                 if (rec_len < EXT2_DIR_REC_LEN(1))
     133          74 :                         goto Eshort;
     134         148 :                 if (rec_len & 3)
     135          74 :                         goto Ealign;
     136         222 :                 if (rec_len < EXT2_DIR_REC_LEN(p->name_len))
     137          74 :                         goto Enamelen;
     138         148 :                 if (((offs + rec_len - 1) ^ offs) & ~(chunk_size-1))
     139          74 :                         goto Espan;
     140         148 :                 if (le32_to_cpu(p->inode) > max_inumber)
     141          74 :                         goto Einumber;
     142             :         }
     143         148 :         if (offs != limit)
     144          74 :                 goto Eend;
     145             : out:
     146         296 :         SetPageChecked(page);
     147          74 :         return;
     148         148 : 
     149             :         /* Too bad, we had an error */
     150             : 
     151             : Ebadsize:
     152         148 :         if (!quiet)
     153         222 :                 ext2_error(sb, __func__,
     154             :                         "size of directory #%lu is not a multiple "
     155             :                         "of chunk size", dir->i_ino);
     156         148 :         goto fail;
     157          74 : Eshort:
     158          74 :         error = "rec_len is smaller than minimal";
     159          74 :         goto bad_entry;
     160          74 : Ealign:
     161          74 :         error = "unaligned directory entry";
     162          74 :         goto bad_entry;
     163          74 : Enamelen:
     164          74 :         error = "rec_len is too small for name_len";
     165          74 :         goto bad_entry;
     166          74 : Espan:
     167          74 :         error = "directory entry across blocks";
     168          74 :         goto bad_entry;
     169          74 : Einumber:
     170          74 :         error = "inode out of bounds";
     171          74 : bad_entry:
     172         148 :         if (!quiet)
     173         370 :                 ext2_error(sb, __func__, "bad entry in directory #%lu: : %s - "
     174             :                         "offset=%lu, inode=%lu, rec_len=%d, name_len=%d",
     175             :                         dir->i_ino, error, (page->index<<PAGE_CACHE_SHIFT)+offs,
     176             :                         (unsigned long) le32_to_cpu(p->inode),
     177             :                         rec_len, p->name_len);
     178         148 :         goto fail;
     179          74 : Eend:
     180         148 :         if (!quiet) {
     181          74 :                 p = (ext2_dirent *)(kaddr + offs);
     182         296 :                 ext2_error(sb, "ext2_check_page",
     183             :                         "entry in directory #%lu spans the page boundary"
     184             :                         "offset=%lu, inode=%lu",
     185             :                         dir->i_ino, (page->index<<PAGE_CACHE_SHIFT)+offs,
     186             :                         (unsigned long) le32_to_cpu(p->inode));
     187             :         }
     188             : fail:
     189        1036 :         SetPageChecked(page);
     190         148 :         SetPageError(page);
     191          74 : }
     192             : 
     193             : static struct page * ext2_get_page(struct inode *dir, unsigned long n,
     194             :                                    int quiet)
     195          74 : {
     196         148 :         struct address_space *mapping = dir->i_mapping;
     197         296 :         struct page *page = read_mapping_page(mapping, n, NULL);
     198         370 :         if (!IS_ERR(page)) {
     199         222 :                 kmap(page);
     200         370 :                 if (!PageChecked(page))
     201         296 :                         ext2_check_page(page, quiet);
     202         444 :                 if (PageError(page))
     203          74 :                         goto fail;
     204             :         }
     205         148 :         return page;
     206          74 : 
     207             : fail:
     208         148 :         ext2_put_page(page);
     209         222 :         return ERR_PTR(-EIO);
     210             : }
     211             : 
     212             : /*
     213             :  * NOTE! unlike strncmp, ext2_match returns 1 for success, 0 for failure.
     214             :  *
     215             :  * len <= EXT2_NAME_LEN and de != NULL are guaranteed by caller.
     216             :  */
     217             : static inline int ext2_match (int len, const char * const name,
     218             :                                         struct ext2_dir_entry_2 * de)
     219          57 : {
     220         171 :         if (len != de->name_len)
     221          57 :                 return 0;
     222         114 :         if (!de->inode)
     223          57 :                 return 0;
     224         114 :         return !memcmp(name, de->name, len);
     225             : }
     226             : 
     227             : /*
     228             :  * p is at least 6 bytes before the end of page
     229             :  */
     230             : static inline ext2_dirent *ext2_next_entry(ext2_dirent *p)
     231             : {
     232         295 :         return (ext2_dirent *)((char *)p +
     233             :                         ext2_rec_len_from_disk(p->rec_len));
     234             : }
     235             : 
     236             : static inline unsigned 
     237             : ext2_validate_entry(char *base, unsigned offset, unsigned mask)
     238             : {
     239           1 :         ext2_dirent *de = (ext2_dirent*)(base + offset);
     240           2 :         ext2_dirent *p = (ext2_dirent*)(base + (offset&mask));
     241           4 :         while ((char*)p < (char*)de) {
     242           4 :                 if (p->rec_len == 0)
     243           2 :                         break;
     244           2 :                 p = ext2_next_entry(p);
     245             :         }
     246           2 :         return (char *)p - base;
     247           1 : }
     248             : 
     249           1 : static unsigned char ext2_filetype_table[EXT2_FT_MAX] = {
     250             :         [EXT2_FT_UNKNOWN]       = DT_UNKNOWN,
     251             :         [EXT2_FT_REG_FILE]      = DT_REG,
     252             :         [EXT2_FT_DIR]           = DT_DIR,
     253             :         [EXT2_FT_CHRDEV]        = DT_CHR,
     254             :         [EXT2_FT_BLKDEV]        = DT_BLK,
     255             :         [EXT2_FT_FIFO]          = DT_FIFO,
     256             :         [EXT2_FT_SOCK]          = DT_SOCK,
     257             :         [EXT2_FT_SYMLINK]       = DT_LNK,
     258             : };
     259             : 
     260             : #define S_SHIFT 12
     261           1 : static unsigned char ext2_type_by_mode[S_IFMT >> S_SHIFT] = {
     262             :         [S_IFREG >> S_SHIFT]      = EXT2_FT_REG_FILE,
     263             :         [S_IFDIR >> S_SHIFT]      = EXT2_FT_DIR,
     264             :         [S_IFCHR >> S_SHIFT]      = EXT2_FT_CHRDEV,
     265             :         [S_IFBLK >> S_SHIFT]      = EXT2_FT_BLKDEV,
     266             :         [S_IFIFO >> S_SHIFT]      = EXT2_FT_FIFO,
     267             :         [S_IFSOCK >> S_SHIFT]     = EXT2_FT_SOCK,
     268             :         [S_IFLNK >> S_SHIFT]      = EXT2_FT_SYMLINK,
     269             : };
     270             : 
     271             : static inline void ext2_set_de_type(ext2_dirent *de, struct inode *inode)
     272             : {
     273         216 :         mode_t mode = inode->i_mode;
     274         360 :         if (EXT2_HAS_INCOMPAT_FEATURE(inode->i_sb, EXT2_FEATURE_INCOMPAT_FILETYPE))
     275          72 :                 de->file_type = ext2_type_by_mode[(mode & S_IFMT)>>S_SHIFT];
     276             :         else
     277          72 :                 de->file_type = 0;
     278          72 : }
     279             : 
     280             : static int
     281             : ext2_readdir (struct file * filp, void * dirent, filldir_t filldir)
     282             : {
     283           1 :         loff_t pos = filp->f_pos;
     284           1 :         struct inode *inode = filp->f_path.dentry->d_inode;
     285           1 :         struct super_block *sb = inode->i_sb;
     286           2 :         unsigned int offset = pos & ~PAGE_CACHE_MASK;
     287           2 :         unsigned long n = pos >> PAGE_CACHE_SHIFT;
     288           4 :         unsigned long npages = dir_pages(inode);
     289           4 :         unsigned chunk_mask = ~(ext2_chunk_size(inode)-1);
     290           2 :         unsigned char *types = NULL;
     291           2 :         int need_revalidate = filp->f_version != inode->i_version;
     292           1 : 
     293           3 :         if (pos > inode->i_size - EXT2_DIR_REC_LEN(1))
     294           2 :                 return 0;
     295           1 : 
     296           5 :         if (EXT2_HAS_INCOMPAT_FEATURE(sb, EXT2_FEATURE_INCOMPAT_FILETYPE))
     297           2 :                 types = ext2_filetype_table;
     298           1 : 
     299           6 :         for ( ; n < npages; n++, offset = 0) {
     300           2 :                 char *kaddr, *limit;
     301           3 :                 ext2_dirent *de;
     302           6 :                 struct page *page = ext2_get_page(inode, n, 0);
     303           1 : 
     304           5 :                 if (IS_ERR(page)) {
     305           4 :                         ext2_error(sb, __func__,
     306           1 :                                    "bad page in #%lu",
     307           1 :                                    inode->i_ino);
     308           3 :                         filp->f_pos += PAGE_CACHE_SIZE - offset;
     309           4 :                         return PTR_ERR(page);
     310           1 :                 }
     311           3 :                 kaddr = page_address(page);
     312           4 :                 if (unlikely(need_revalidate)) {
     313           2 :                         if (offset) {
     314           2 :                                 offset = ext2_validate_entry(kaddr, offset, chunk_mask);
     315           1 :                                 filp->f_pos = (n<<PAGE_CACHE_SHIFT) + offset;
     316             :                         }
     317           2 :                         filp->f_version = inode->i_version;
     318           2 :                         need_revalidate = 0;
     319             :                 }
     320           2 :                 de = (ext2_dirent *)(kaddr+offset);
     321           5 :                 limit = kaddr + ext2_last_byte(inode, n) - EXT2_DIR_REC_LEN(1);
     322           5 :                 for ( ;(char*)de <= limit; de = ext2_next_entry(de)) {
     323           4 :                         if (de->rec_len == 0) {
     324           5 :                                 ext2_error(sb, __func__,
     325             :                                         "zero-length directory entry");
     326           2 :                                 ext2_put_page(page);
     327           1 :                                 return -EIO;
     328             :                         }
     329           2 :                         if (de->inode) {
     330             :                                 int over;
     331           1 :                                 unsigned char d_type = DT_UNKNOWN;
     332             : 
     333           5 :                                 if (types && de->file_type < EXT2_FT_MAX)
     334           2 :                                         d_type = types[de->file_type];
     335             : 
     336           1 :                                 offset = (char *)de - kaddr;
     337           3 :                                 over = filldir(dirent, de->name, de->name_len,
     338             :                                                 (n<<PAGE_CACHE_SHIFT) | offset,
     339             :                                                 le32_to_cpu(de->inode), d_type);
     340           2 :                                 if (over) {
     341           2 :                                         ext2_put_page(page);
     342           1 :                                         return 0;
     343             :                                 }
     344             :                         }
     345           4 :                         filp->f_pos += ext2_rec_len_from_disk(de->rec_len);
     346             :                 }
     347           2 :                 ext2_put_page(page);
     348             :         }
     349           1 :         return 0;
     350             : }
     351             : 
     352             : /*
     353             :  *      ext2_find_entry()
     354             :  *
     355             :  * finds an entry in the specified directory with the wanted name. It
     356             :  * returns the page in which the entry was found (as a parameter - res_page),
     357             :  * and the entry itself. Page is returned mapped and unlocked.
     358             :  * Entry is guaranteed to be valid.
     359             :  */
     360             : struct ext2_dir_entry_2 *ext2_find_entry (struct inode * dir,
     361             :                         struct qstr *child, struct page ** res_page)
     362             : {
     363          87 :         const char *name = child->name;
     364          87 :         int namelen = child->len;
     365          58 :         unsigned reclen = EXT2_DIR_REC_LEN(namelen);
     366          29 :         unsigned long start, n;
     367         116 :         unsigned long npages = dir_pages(dir);
     368          58 :         struct page *page = NULL;
     369         116 :         struct ext2_inode_info *ei = EXT2_I(dir);
     370          29 :         ext2_dirent * de;
     371          58 :         int dir_has_error = 0;
     372          29 : 
     373          87 :         if (npages == 0)
     374          58 :                 goto out;
     375          29 : 
     376          29 :         /* OFFSET_CACHE */
     377          58 :         *res_page = NULL;
     378          29 : 
     379          87 :         start = ei->i_dir_start_lookup;
     380          87 :         if (start >= npages)
     381          29 :                 start = 0;
     382          29 :         n = start;
     383          29 :         do {
     384             :                 char *kaddr;
     385         116 :                 page = ext2_get_page(dir, n, dir_has_error);
     386         116 :                 if (!IS_ERR(page)) {
     387          87 :                         kaddr = page_address(page);
     388          29 :                         de = (ext2_dirent *) kaddr;
     389          87 :                         kaddr += ext2_last_byte(dir, n) - reclen;
     390          87 :                         while ((char *) de <= kaddr) {
     391         116 :                                 if (de->rec_len == 0) {
     392         116 :                                         ext2_error(dir->i_sb, __func__,
     393             :                                                 "zero-length directory entry");
     394          58 :                                         ext2_put_page(page);
     395          29 :                                         goto out;
     396             :                                 }
     397         116 :                                 if (ext2_match (namelen, name, de))
     398          29 :                                         goto found;
     399          58 :                                 de = ext2_next_entry(de);
     400             :                         }
     401          87 :                         ext2_put_page(page);
     402             :                 } else
     403          29 :                         dir_has_error = 1;
     404             : 
     405         174 :                 if (++n >= npages)
     406          58 :                         n = 0;
     407             :                 /* next page is past the blocks we've got */
     408         174 :                 if (unlikely(n > (dir->i_blocks >> (PAGE_CACHE_SHIFT - 9)))) {
     409         116 :                         ext2_error(dir->i_sb, __func__,
     410             :                                 "dir %lu size %lld exceeds block count %llu",
     411             :                                 dir->i_ino, dir->i_size,
     412             :                                 (unsigned long long)dir->i_blocks);
     413          29 :                         goto out;
     414             :                 }
     415          58 :         } while (n != start);
     416             : out:
     417         145 :         return NULL;
     418          29 : 
     419             : found:
     420          29 :         *res_page = page;
     421          29 :         ei->i_dir_start_lookup = n;
     422          58 :         return de;
     423             : }
     424             : 
     425             : struct ext2_dir_entry_2 * ext2_dotdot (struct inode *dir, struct page **p)
     426             : {
     427          24 :         struct page *page = ext2_get_page(dir, 0, 0);
     428           8 :         ext2_dirent *de = NULL;
     429           4 : 
     430          20 :         if (!IS_ERR(page)) {
     431          20 :                 de = ext2_next_entry((ext2_dirent *) page_address(page));
     432           4 :                 *p = page;
     433             :         }
     434           8 :         return de;
     435             : }
     436             : 
     437             : ino_t ext2_inode_by_name(struct inode *dir, struct qstr *child)
     438             : {
     439          10 :         ino_t res = 0;
     440           5 :         struct ext2_dir_entry_2 *de;
     441           5 :         struct page *page;
     442             :         
     443          30 :         de = ext2_find_entry (dir, child, &page);
     444          10 :         if (de) {
     445          10 :                 res = le32_to_cpu(de->inode);
     446          10 :                 ext2_put_page(page);
     447             :         }
     448          10 :         return res;
     449             : }
     450             : 
     451             : /* Releases the page */
     452             : void ext2_set_link(struct inode *dir, struct ext2_dir_entry_2 *de,
     453             :                    struct page *page, struct inode *inode, int update_times)
     454             : {
     455          48 :         loff_t pos = page_offset(page) +
     456           8 :                         (char *) de - (char *) page_address(page);
     457          40 :         unsigned len = ext2_rec_len_from_disk(de->rec_len);
     458           8 :         int err;
     459           8 : 
     460          24 :         lock_page(page);
     461          24 :         err = __ext2_write_begin(NULL, page->mapping, pos, len,
     462           8 :                                 AOP_FLAG_UNINTERRUPTIBLE, &page, NULL);
     463          56 :         BUG_ON(err);
     464          24 :         de->inode = cpu_to_le32(inode->i_ino);
     465          24 :         ext2_set_de_type(de, inode);
     466          32 :         err = ext2_commit_chunk(page, pos, len);
     467          16 :         ext2_put_page(page);
     468          16 :         if (update_times)
     469          48 :                 dir->i_mtime = dir->i_ctime = CURRENT_TIME_SEC;
     470          24 :         EXT2_I(dir)->i_flags &= ~EXT2_BTREE_FL;
     471          16 :         mark_inode_dirty(dir);
     472           8 : }
     473             : 
     474             : /*
     475             :  *      Parent is locked.
     476             :  */
     477             : int ext2_add_link (struct dentry *dentry, struct inode *inode)
     478             : {
     479          56 :         struct inode *dir = dentry->d_parent->d_inode;
     480          56 :         const char *name = dentry->d_name.name;
     481          56 :         int namelen = dentry->d_name.len;
     482         112 :         unsigned chunk_size = ext2_chunk_size(dir);
     483          56 :         unsigned reclen = EXT2_DIR_REC_LEN(namelen);
     484          28 :         unsigned short rec_len, name_len;
     485          56 :         struct page *page = NULL;
     486          28 :         ext2_dirent * de;
     487         112 :         unsigned long npages = dir_pages(dir);
     488          28 :         unsigned long n;
     489          28 :         char *kaddr;
     490          28 :         loff_t pos;
     491          28 :         int err;
     492          28 : 
     493          28 :         /*
     494          28 :          * We take care of directory expansion in the same loop.
     495          28 :          * This code plays outside i_size, so it locks the page
     496          28 :          * to protect that region.
     497          28 :          */
     498         168 :         for (n = 0; n <= npages; n++) {
     499          56 :                 char *dir_end;
     500          84 : 
     501         140 :                 page = ext2_get_page(dir, n, 0);
     502         112 :                 err = PTR_ERR(page);
     503         140 :                 if (IS_ERR(page))
     504          56 :                         goto out;
     505          84 :                 lock_page(page);
     506         112 :                 kaddr = page_address(page);
     507         112 :                 dir_end = kaddr + ext2_last_byte(dir, n);
     508          56 :                 de = (ext2_dirent *)kaddr;
     509          28 :                 kaddr += PAGE_CACHE_SIZE - reclen;
     510          84 :                 while ((char *)de <= kaddr) {
     511          84 :                         if ((char *)de == dir_end) {
     512          28 :                                 /* We hit i_size */
     513          28 :                                 name_len = 0;
     514          28 :                                 rec_len = chunk_size;
     515          84 :                                 de->rec_len = ext2_rec_len_to_disk(chunk_size);
     516          28 :                                 de->inode = 0;
     517          28 :                                 goto got_it;
     518             :                         }
     519          84 :                         if (de->rec_len == 0) {
     520          84 :                                 ext2_error(dir->i_sb, __func__,
     521             :                                         "zero-length directory entry");
     522          28 :                                 err = -EIO;
     523          28 :                                 goto out_unlock;
     524             :                         }
     525          28 :                         err = -EEXIST;
     526         112 :                         if (ext2_match (namelen, name, de))
     527          28 :                                 goto out_unlock;
     528          56 :                         name_len = EXT2_DIR_REC_LEN(de->name_len);
     529         112 :                         rec_len = ext2_rec_len_from_disk(de->rec_len);
     530         112 :                         if (!de->inode && rec_len >= reclen)
     531          28 :                                 goto got_it;
     532          56 :                         if (rec_len >= name_len + reclen)
     533          28 :                                 goto got_it;
     534          28 :                         de = (ext2_dirent *) ((char *) de + rec_len);
     535          28 :                 }
     536          28 :                 unlock_page(page);
     537          56 :                 ext2_put_page(page);
     538             :         }
     539          56 :         BUG();
     540          28 :         return -EINVAL;
     541          56 : 
     542             : got_it:
     543         196 :         pos = page_offset(page) +
     544             :                 (char*)de - (char*)page_address(page);
     545          56 :         err = __ext2_write_begin(NULL, page->mapping, pos, rec_len, 0,
     546             :                                                         &page, NULL);
     547          56 :         if (err)
     548          28 :                 goto out_unlock;
     549          56 :         if (de->inode) {
     550          28 :                 ext2_dirent *de1 = (ext2_dirent *) ((char *) de + name_len);
     551          84 :                 de1->rec_len = ext2_rec_len_to_disk(rec_len - name_len);
     552          84 :                 de->rec_len = ext2_rec_len_to_disk(name_len);
     553          28 :                 de = de1;
     554             :         }
     555          56 :         de->name_len = namelen;
     556          56 :         memcpy(de->name, name, namelen);
     557         112 :         de->inode = cpu_to_le32(inode->i_ino);
     558         112 :         ext2_set_de_type (de, inode);
     559         112 :         err = ext2_commit_chunk(page, pos, rec_len);
     560         168 :         dir->i_mtime = dir->i_ctime = CURRENT_TIME_SEC;
     561          84 :         EXT2_I(dir)->i_flags &= ~EXT2_BTREE_FL;
     562          56 :         mark_inode_dirty(dir);
     563             :         /* OFFSET_CACHE */
     564          28 : out_put:
     565         224 :         ext2_put_page(page);
     566             : out:
     567          84 :         return err;
     568          84 : out_unlock:
     569          84 :         unlock_page(page);
     570          84 :         goto out_put;
     571             : }
     572             : 
     573             : /*
     574             :  * ext2_delete_entry deletes a directory entry by merging it with the
     575             :  * previous entry. Page is up-to-date. Releases the page.
     576             :  */
     577             : int ext2_delete_entry (struct ext2_dir_entry_2 * dir, struct page * page )
     578             : {
     579          24 :         struct address_space *mapping = page->mapping;
     580          24 :         struct inode *inode = mapping->host;
     581          48 :         char *kaddr = page_address(page);
     582          48 :         unsigned from = ((char*)dir - kaddr) & ~(ext2_chunk_size(inode)-1);
     583          60 :         unsigned to = ((char *)dir - kaddr) +
     584          12 :                                 ext2_rec_len_from_disk(dir->rec_len);
     585          12 :         loff_t pos;
     586          24 :         ext2_dirent * pde = NULL;
     587          24 :         ext2_dirent * de = (ext2_dirent *) (kaddr + from);
     588          12 :         int err;
     589          12 : 
     590          48 :         while ((char*)de < (char*)dir) {
     591          60 :                 if (de->rec_len == 0) {
     592          60 :                         ext2_error(inode->i_sb, __func__,
     593          12 :                                 "zero-length directory entry");
     594          24 :                         err = -EIO;
     595          24 :                         goto out;
     596          12 :                 }
     597          24 :                 pde = de;
     598          24 :                 de = ext2_next_entry(de);
     599             :         }
     600          36 :         if (pde)
     601          36 :                 from = (char*)pde - (char*)page_address(page);
     602          60 :         pos = page_offset(page) + from;
     603          24 :         lock_page(page);
     604          24 :         err = __ext2_write_begin(NULL, page->mapping, pos, to - from, 0,
     605             :                                                         &page, NULL);
     606          72 :         BUG_ON(err);
     607          24 :         if (pde)
     608          36 :                 pde->rec_len = ext2_rec_len_to_disk(to - from);
     609          24 :         dir->inode = 0;
     610          96 :         err = ext2_commit_chunk(page, pos, to - from);
     611          72 :         inode->i_ctime = inode->i_mtime = CURRENT_TIME_SEC;
     612          36 :         EXT2_I(inode)->i_flags &= ~EXT2_BTREE_FL;
     613          24 :         mark_inode_dirty(inode);
     614             : out:
     615          60 :         ext2_put_page(page);
     616          12 :         return err;
     617             : }
     618             : 
     619             : /*
     620             :  * Set the first fragment of directory.
     621             :  */
     622             : int ext2_make_empty(struct inode *inode, struct inode *parent)
     623             : {
     624           8 :         struct address_space *mapping = inode->i_mapping;
     625          16 :         struct page *page = grab_cache_page(mapping, 0);
     626          16 :         unsigned chunk_size = ext2_chunk_size(inode);
     627           4 :         struct ext2_dir_entry_2 * de;
     628           4 :         int err;
     629           4 :         void *kaddr;
     630           4 : 
     631          12 :         if (!page)
     632           4 :                 return -ENOMEM;
     633             : 
     634           8 :         err = __ext2_write_begin(NULL, page->mapping, 0, chunk_size, 0,
     635             :                                                         &page, NULL);
     636           8 :         if (err) {
     637           4 :                 unlock_page(page);
     638           4 :                 goto fail;
     639             :         }
     640           8 :         kaddr = kmap_atomic(page, KM_USER0);
     641           4 :         memset(kaddr, 0, chunk_size);
     642           4 :         de = (struct ext2_dir_entry_2 *)kaddr;
     643           4 :         de->name_len = 1;
     644          12 :         de->rec_len = ext2_rec_len_to_disk(EXT2_DIR_REC_LEN(1));
     645           4 :         memcpy (de->name, ".\0\0", 4);
     646           8 :         de->inode = cpu_to_le32(inode->i_ino);
     647           8 :         ext2_set_de_type (de, inode);
     648             : 
     649           4 :         de = (struct ext2_dir_entry_2 *)(kaddr + EXT2_DIR_REC_LEN(1));
     650           4 :         de->name_len = 2;
     651          12 :         de->rec_len = ext2_rec_len_to_disk(chunk_size - EXT2_DIR_REC_LEN(1));
     652           8 :         de->inode = cpu_to_le32(parent->i_ino);
     653           4 :         memcpy (de->name, "..\0", 4);
     654           8 :         ext2_set_de_type (de, inode);
     655           8 :         kunmap_atomic(kaddr, KM_USER0);
     656          16 :         err = ext2_commit_chunk(page, 0, chunk_size);
     657             : fail:
     658          12 :         page_cache_release(page);
     659           8 :         return err;
     660             : }
     661             : 
     662             : /*
     663             :  * routine to check that the specified directory is empty (for rmdir)
     664             :  */
     665             : int ext2_empty_dir (struct inode * inode)
     666             : {
     667          24 :         struct page *page = NULL;
     668          48 :         unsigned long i, npages = dir_pages(inode);
     669          24 :         int dir_has_error = 0;
     670          12 : 
     671          84 :         for (i = 0; i < npages; i++) {
     672          48 :                 char *kaddr;
     673          24 :                 ext2_dirent * de;
     674          60 :                 page = ext2_get_page(inode, i, dir_has_error);
     675          12 : 
     676          60 :                 if (IS_ERR(page)) {
     677          12 :                         dir_has_error = 1;
     678          12 :                         continue;
     679             :                 }
     680             : 
     681          36 :                 kaddr = page_address(page);
     682          12 :                 de = (ext2_dirent *)kaddr;
     683          36 :                 kaddr += ext2_last_byte(inode, i) - EXT2_DIR_REC_LEN(1);
     684             : 
     685          36 :                 while ((char *)de <= kaddr) {
     686          48 :                         if (de->rec_len == 0) {
     687          48 :                                 ext2_error(inode->i_sb, __func__,
     688             :                                         "zero-length directory entry");
     689          12 :                                 printk("kaddr=%p, de=%p\n", kaddr, de);
     690          12 :                                 goto not_empty;
     691             :                         }
     692          24 :                         if (de->inode != 0) {
     693             :                                 /* check for . and .. */
     694          24 :                                 if (de->name[0] != '.')
     695          12 :                                         goto not_empty;
     696          36 :                                 if (de->name_len > 2)
     697          12 :                                         goto not_empty;
     698          36 :                                 if (de->name_len < 2) {
     699          36 :                                         if (de->inode !=
     700             :                                             cpu_to_le32(inode->i_ino))
     701          12 :                                                 goto not_empty;
     702          24 :                                 } else if (de->name[1] != '.')
     703          12 :                                         goto not_empty;
     704             :                         }
     705          24 :                         de = ext2_next_entry(de);
     706             :                 }
     707          36 :                 ext2_put_page(page);
     708             :         }
     709          24 :         return 1;
     710          24 : 
     711             : not_empty:
     712          48 :         ext2_put_page(page);
     713          12 :         return 0;
     714             : }
     715             : 
     716           1 : const struct file_operations ext2_dir_operations = {
     717             :         .llseek         = generic_file_llseek,
     718             :         .read           = generic_read_dir,
     719             :         .readdir        = ext2_readdir,
     720             :         .unlocked_ioctl = ext2_ioctl,
     721             : #ifdef CONFIG_COMPAT
     722             :         .compat_ioctl   = ext2_compat_ioctl,
     723             : #endif
     724             :         .fsync          = ext2_fsync,
     725             : };

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