]> git.sur5r.net Git - u-boot/commitdiff
ext4: Scan all directory blocks when looking up an entry
authorStefan Brüns <stefan.bruens@rwth-aachen.de>
Tue, 6 Sep 2016 02:36:46 +0000 (04:36 +0200)
committerTom Rini <trini@konsulko.com>
Fri, 23 Sep 2016 13:02:38 +0000 (09:02 -0400)
Scanning only the direct blocks of the directory file may falsely report
an existing file as nonexisting, and worse can also lead to creation
of a duplicate entry on file creation.

Signed-off-by: Stefan Brüns <stefan.bruens@rwth-aachen.de>
Reviewed-by: Lukasz Majewski <l.majewski@samsung.com>
fs/ext4/ext4_common.c

index 3937e978e179d0840fb959b902c6df49ad953a0c..deca954e08c300b00180032898888779e35acf15 100644 (file)
@@ -525,64 +525,57 @@ static int search_dir(struct ext2_inode *parent_inode, char *dirname)
 {
        int status;
        int inodeno = 0;
-       int totalbytes;
-       int templength;
-       int direct_blk_idx;
+       int offset;
+       int blk_idx;
        long int blknr;
-       char *ptr = NULL;
-       unsigned char *block_buffer = NULL;
+       char *block_buffer = NULL;
        struct ext2_dirent *dir = NULL;
        struct ext_filesystem *fs = get_fs();
+       uint32_t directory_blocks;
+       char *direntname;
 
-       /* read the block no allocated to a file */
-       for (direct_blk_idx = 0; direct_blk_idx < INDIRECT_BLOCKS;
-               direct_blk_idx++) {
-               blknr = read_allocated_block(parent_inode, direct_blk_idx);
-               if (blknr == 0)
-                       goto fail;
+       directory_blocks = le32_to_cpu(parent_inode->size) >>
+               LOG2_BLOCK_SIZE(ext4fs_root);
 
-               /* read the blocks of parent inode */
-               block_buffer = zalloc(fs->blksz);
-               if (!block_buffer)
+       block_buffer = zalloc(fs->blksz);
+       if (!block_buffer)
+               goto fail;
+
+       /* get the block no allocated to a file */
+       for (blk_idx = 0; blk_idx < directory_blocks; blk_idx++) {
+               blknr = read_allocated_block(parent_inode, blk_idx);
+               if (blknr == 0)
                        goto fail;
 
+               /* read the directory block */
                status = ext4fs_devread((lbaint_t)blknr * fs->sect_perblk,
                                        0, fs->blksz, (char *)block_buffer);
                if (status == 0)
                        goto fail;
 
-               dir = (struct ext2_dirent *)block_buffer;
-               ptr = (char *)dir;
-               totalbytes = 0;
-               while (le16_to_cpu(dir->direntlen) >= 0) {
-                       /*
-                        * blocksize-totalbytes because last directory
-                        * length i.e.,*dir->direntlen is free availble
-                        * space in the block that means
-                        * it is a last entry of directory entry
-                        */
-                       if (dir->inode && (strlen(dirname) == dir->namelen)) {
-                               if (strncmp(dirname, ptr + sizeof(struct ext2_dirent), dir->namelen) == 0) {
-                                       inodeno = le32_to_cpu(dir->inode);
-                                       break;
-                               }
-                       }
+               offset = 0;
+               do {
+                       dir = (struct ext2_dirent *)(block_buffer + offset);
+                       direntname = (char*)(dir) + sizeof(struct ext2_dirent);
 
-                       if (fs->blksz - totalbytes == le16_to_cpu(dir->direntlen))
+                       int direntlen = le16_to_cpu(dir->direntlen);
+                       if (direntlen < sizeof(struct ext2_dirent))
                                break;
 
-                       /* traversing the each directory entry */
-                       templength = le16_to_cpu(dir->direntlen);
-                       totalbytes = totalbytes + templength;
-                       dir = (struct ext2_dirent *)((char *)dir + templength);
-                       ptr = (char *)dir;
-               }
+                       if (dir->inode && (strlen(dirname) == dir->namelen) &&
+                           (strncmp(dirname, direntname, dir->namelen) == 0)) {
+                               inodeno = le32_to_cpu(dir->inode);
+                               break;
+                       }
+
+                       offset += direntlen;
 
-               free(block_buffer);
-               block_buffer = NULL;
+               } while (offset < fs->blksz);
 
-               if (inodeno > 0)
+               if (inodeno > 0) {
+                       free(block_buffer);
                        return inodeno;
+               }
        }
 
 fail:
@@ -834,14 +827,17 @@ fail:
 
 int ext4fs_filename_unlink(char *filename)
 {
-       short direct_blk_idx = 0;
+       int blk_idx;
        long int blknr = -1;
        int inodeno = -1;
+       uint32_t directory_blocks;
+
+       directory_blocks = le32_to_cpu(g_parent_inode->size) >>
+               LOG2_BLOCK_SIZE(ext4fs_root);
 
        /* read the block no allocated to a file */
-       for (direct_blk_idx = 0; direct_blk_idx < INDIRECT_BLOCKS;
-               direct_blk_idx++) {
-               blknr = read_allocated_block(g_parent_inode, direct_blk_idx);
+       for (blk_idx = 0; blk_idx < directory_blocks; blk_idx++) {
+               blknr = read_allocated_block(g_parent_inode, blk_idx);
                if (blknr == 0)
                        break;
                inodeno = unlink_filename(filename, blknr);