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libext2fs: don't use O_DIRECT for files on tmpfs
[tools/e2fsprogs.git] / lib / ext2fs / dir_iterate.c
index 40c289b..b2b7769 100644 (file)
 /*
  * dir_iterate.c --- ext2fs directory iteration operations
- * 
+ *
  * Copyright (C) 1993, 1994, 1994, 1995, 1996, 1997 Theodore Ts'o.
  *
  * %Begin-Header%
- * This file may be redistributed under the terms of the GNU Public
- * License.
+ * This file may be redistributed under the terms of the GNU Library
+ * General Public License, version 2.
  * %End-Header%
  */
 
+#include "config.h"
 #include <stdio.h>
 #include <string.h>
 #if HAVE_UNISTD_H
 #include <unistd.h>
 #endif
-#include <stdlib.h>
 #if HAVE_ERRNO_H
 #include <errno.h>
 #endif
 
-#include <linux/ext2_fs.h>
-
+#include "ext2_fs.h"
 #include "ext2fsP.h"
 
-errcode_t ext2fs_dir_iterate(ext2_filsys fs,
-                            ino_t dir,
-                            int flags,
-                            char *block_buf,
-                            int (*func)(struct ext2_dir_entry *dirent,
-                                        int    offset,
-                                        int    blocksize,
-                                        char   *buf,
-                                        void   *private),
-                            void *private)
+#define EXT4_MAX_REC_LEN               ((1<<16)-1)
+
+errcode_t ext2fs_get_rec_len(ext2_filsys fs,
+                            struct ext2_dir_entry *dirent,
+                            unsigned int *rec_len)
+{
+       unsigned int len = dirent->rec_len;
+
+       if (fs->blocksize < 65536)
+               *rec_len = len;
+       else if (len == EXT4_MAX_REC_LEN || len == 0)
+               *rec_len = fs->blocksize;
+       else 
+               *rec_len = (len & 65532) | ((len & 3) << 16);
+       return 0;
+}
+
+errcode_t ext2fs_set_rec_len(ext2_filsys fs,
+                            unsigned int len,
+                            struct ext2_dir_entry *dirent)
+{
+       if ((len > fs->blocksize) || (fs->blocksize > (1 << 18)) || (len & 3))
+               return EINVAL;
+       if (len < 65536) {
+               dirent->rec_len = len;
+               return 0;
+       }
+       if (len == fs->blocksize) {
+               if (fs->blocksize == 65536)
+                       dirent->rec_len = EXT4_MAX_REC_LEN;
+               else 
+                       dirent->rec_len = 0;
+       } else
+               dirent->rec_len = (len & 65532) | ((len >> 16) & 3);
+       return 0;
+}
+
+/*
+ * This function checks to see whether or not a potential deleted
+ * directory entry looks valid.  What we do is check the deleted entry
+ * and each successive entry to make sure that they all look valid and
+ * that the last deleted entry ends at the beginning of the next
+ * undeleted entry.  Returns 1 if the deleted entry looks valid, zero
+ * if not valid.
+ */
+static int ext2fs_validate_entry(ext2_filsys fs, char *buf,
+                                unsigned int offset,
+                                unsigned int final_offset)
+{
+       struct ext2_dir_entry *dirent;
+       unsigned int rec_len;
+#define DIRENT_MIN_LENGTH 12
+
+       while ((offset < final_offset) &&
+              (offset <= fs->blocksize - DIRENT_MIN_LENGTH)) {
+               dirent = (struct ext2_dir_entry *)(buf + offset);
+               if (ext2fs_get_rec_len(fs, dirent, &rec_len))
+                       return 0;
+               offset += rec_len;
+               if ((rec_len < 8) ||
+                   ((rec_len % 4) != 0) ||
+                   ((ext2fs_dirent_name_len(dirent)+8) > (int) rec_len))
+                       return 0;
+       }
+       return (offset == final_offset);
+}
+
+errcode_t ext2fs_dir_iterate2(ext2_filsys fs,
+                             ext2_ino_t dir,
+                             int flags,
+                             char *block_buf,
+                             int (*func)(ext2_ino_t    dir,
+                                         int           entry,
+                                         struct ext2_dir_entry *dirent,
+                                         int   offset,
+                                         int   blocksize,
+                                         char  *buf,
+                                         void  *priv_data),
+                             void *priv_data)
 {
        struct          dir_context     ctx;
        errcode_t       retval;
-       
+
        EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
 
        retval = ext2fs_check_directory(fs, dir);
        if (retval)
                return retval;
-       
+
        ctx.dir = dir;
        ctx.flags = flags;
        if (block_buf)
                ctx.buf = block_buf;
        else {
-               ctx.buf = malloc(fs->blocksize);
-               if (!ctx.buf)
-                       return ENOMEM;
+               retval = ext2fs_get_mem(fs->blocksize, &ctx.buf);
+               if (retval)
+                       return retval;
        }
        ctx.func = func;
-       ctx.func2 = 0;
-       ctx.private = private;
+       ctx.priv_data = priv_data;
        ctx.errcode = 0;
-       retval = ext2fs_block_iterate(fs, dir, 0, 0,
-                                     ext2fs_process_dir_block, &ctx);
+       retval = ext2fs_block_iterate3(fs, dir, BLOCK_FLAG_READ_ONLY, 0,
+                                      ext2fs_process_dir_block, &ctx);
        if (!block_buf)
-               free(ctx.buf);
+               ext2fs_free_mem(&ctx.buf);
+       if (retval == EXT2_ET_INLINE_DATA_CANT_ITERATE) {
+               (void) ext2fs_inline_data_dir_iterate(fs, dir, &ctx);
+               retval = 0;
+       }
        if (retval)
                return retval;
        return ctx.errcode;
 }
 
+struct xlate {
+       int (*func)(struct ext2_dir_entry *dirent,
+                   int         offset,
+                   int         blocksize,
+                   char        *buf,
+                   void        *priv_data);
+       void *real_private;
+};
+
+static int xlate_func(ext2_ino_t dir EXT2FS_ATTR((unused)),
+                     int entry EXT2FS_ATTR((unused)),
+                     struct ext2_dir_entry *dirent, int offset,
+                     int blocksize, char *buf, void *priv_data)
+{
+       struct xlate *xl = (struct xlate *) priv_data;
+
+       return (*xl->func)(dirent, offset, blocksize, buf, xl->real_private);
+}
+
+errcode_t ext2fs_dir_iterate(ext2_filsys fs,
+                            ext2_ino_t dir,
+                            int flags,
+                            char *block_buf,
+                            int (*func)(struct ext2_dir_entry *dirent,
+                                        int    offset,
+                                        int    blocksize,
+                                        char   *buf,
+                                        void   *priv_data),
+                            void *priv_data)
+{
+       struct xlate xl;
+
+       xl.real_private = priv_data;
+       xl.func = func;
+
+       return ext2fs_dir_iterate2(fs, dir, flags, block_buf,
+                                  xlate_func, &xl);
+}
+
+
 /*
  * Helper function which is private to this module.  Used by
  * ext2fs_dir_iterate() and ext2fs_dblist_dir_iterate()
  */
-extern int ext2fs_process_dir_block(ext2_filsys        fs,
-                                   blk_t               *blocknr,
-                                   int         blockcnt,
-                                   void                *private)
+int ext2fs_process_dir_block(ext2_filsys fs,
+                            blk64_t    *blocknr,
+                            e2_blkcnt_t blockcnt,
+                            blk64_t    ref_block EXT2FS_ATTR((unused)),
+                            int        ref_offset EXT2FS_ATTR((unused)),
+                            void       *priv_data)
 {
-       struct dir_context *ctx = (struct dir_context *) private;
-       int             offset = 0;
+       struct dir_context *ctx = (struct dir_context *) priv_data;
+       unsigned int    offset = 0;
+       unsigned int    next_real_entry = 0;
        int             ret = 0;
        int             changed = 0;
        int             do_abort = 0;
+       unsigned int    rec_len, size, buflen;
        int             entry;
        struct ext2_dir_entry *dirent;
+       int             csum_size = 0;
+       int             inline_data;
+       errcode_t       retval = 0;
 
        if (blockcnt < 0)
                return 0;
 
-       ctx->errcode = ext2fs_read_dir_block(fs, *blocknr, ctx->buf);
-       if (ctx->errcode)
-               return BLOCK_ABORT;
-
        entry = blockcnt ? DIRENT_OTHER_FILE : DIRENT_DOT_FILE;
-       
-       while (offset < fs->blocksize) {
+
+       /* If a dir has inline data, we don't need to read block */
+       inline_data = !!(ctx->flags & DIRENT_FLAG_INCLUDE_INLINE_DATA);
+       if (!inline_data) {
+               ctx->errcode = ext2fs_read_dir_block4(fs, *blocknr, ctx->buf, 0,
+                                                     ctx->dir);
+               if (ctx->errcode)
+                       return BLOCK_ABORT;
+               /* If we handle a normal dir, we traverse the entire block */
+               buflen = fs->blocksize;
+       } else {
+               buflen = ctx->buflen;
+       }
+
+       if (ext2fs_has_feature_metadata_csum(fs->super))
+               csum_size = sizeof(struct ext2_dir_entry_tail);
+
+       while (offset < buflen - 8) {
                dirent = (struct ext2_dir_entry *) (ctx->buf + offset);
-               if (!dirent->inode &&
-                   !(ctx->flags & DIRENT_FLAG_INCLUDE_EMPTY))
-                       goto next;
-
-               if (ctx->func)
-                       ret = (ctx->func)(dirent, offset, fs->blocksize,
-                                         ctx->buf, ctx->private);
-               else if (ctx->func2) {
-                       ret = (ctx->func2)(ctx->dir, entry, dirent, offset,
-                                          fs->blocksize, ctx->buf,
-                                          ctx->private);
-                       if (entry < DIRENT_OTHER_FILE)
-                               entry++;
+               if (ext2fs_get_rec_len(fs, dirent, &rec_len))
+                       return BLOCK_ABORT;
+               if (((offset + rec_len) > buflen) ||
+                   (rec_len < 8) ||
+                   ((rec_len % 4) != 0) ||
+                   ((ext2fs_dirent_name_len(dirent)+8) > (int) rec_len)) {
+                       ctx->errcode = EXT2_ET_DIR_CORRUPTED;
+                       return BLOCK_ABORT;
+               }
+               if (!dirent->inode) {
+                       /*
+                        * We just need to check metadata_csum when this
+                        * dir hasn't inline data.  That means that 'buflen'
+                        * should be blocksize.
+                        */
+                       if (!inline_data &&
+                           (offset == buflen - csum_size) &&
+                           (dirent->rec_len == csum_size) &&
+                           (dirent->name_len == EXT2_DIR_NAME_LEN_CSUM)) {
+                               if (!(ctx->flags & DIRENT_FLAG_INCLUDE_CSUM))
+                                       goto next;
+                               entry = DIRENT_CHECKSUM;
+                       } else if (!(ctx->flags & DIRENT_FLAG_INCLUDE_EMPTY))
+                               goto next;
                }
-                       
-               if (ret & DIRENT_CHANGED)
+
+               ret = (ctx->func)(ctx->dir,
+                                 (next_real_entry > offset) ?
+                                 DIRENT_DELETED_FILE : entry,
+                                 dirent, offset,
+                                 buflen, ctx->buf,
+                                 ctx->priv_data);
+               if (entry < DIRENT_OTHER_FILE)
+                       entry++;
+
+               if (ret & DIRENT_CHANGED) {
+                       if (ext2fs_get_rec_len(fs, dirent, &rec_len))
+                               return BLOCK_ABORT;
                        changed++;
+               }
                if (ret & DIRENT_ABORT) {
                        do_abort++;
                        break;
                }
-next:          
-               if (((offset + dirent->rec_len) > fs->blocksize) ||
-                   (dirent->rec_len < 8) ||
-                   ((dirent->name_len+8) > dirent->rec_len)) {
-                       ctx->errcode = EXT2_ET_DIR_CORRUPTED;
-                       return BLOCK_ABORT;
+next:
+               if (next_real_entry == offset)
+                       next_real_entry += rec_len;
+
+               if (ctx->flags & DIRENT_FLAG_INCLUDE_REMOVED) {
+                       size = (ext2fs_dirent_name_len(dirent) + 11) & ~3;
+
+                       if (rec_len != size)  {
+                               unsigned int final_offset;
+
+                               final_offset = offset + rec_len;
+                               offset += size;
+                               while (offset < final_offset &&
+                                      !ext2fs_validate_entry(fs, ctx->buf,
+                                                             offset,
+                                                             final_offset))
+                                       offset += 4;
+                               continue;
+                       }
                }
-               offset += dirent->rec_len;
+               offset += rec_len;
        }
 
        if (changed) {
-               ctx->errcode = ext2fs_write_dir_block(fs, *blocknr, ctx->buf);
-               if (ctx->errcode)
-                       return BLOCK_ABORT;
+               if (!inline_data) {
+                       ctx->errcode = ext2fs_write_dir_block4(fs, *blocknr,
+                                                              ctx->buf,
+                                                              0, ctx->dir);
+                       if (ctx->errcode)
+                               return BLOCK_ABORT;
+               } else {
+                       /*
+                        * return BLOCK_INLINE_DATA_CHANGED to notify caller
+                        * that inline data has been changed.
+                        */
+                       retval = BLOCK_INLINE_DATA_CHANGED;
+               }
        }
        if (do_abort)
-               return BLOCK_ABORT;
-       return 0;
+               return retval | BLOCK_ABORT;
+       return retval;
 }
-