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authorStefan Brüns <stefan.bruens@rwth-aachen.de>2016-09-06 05:36:46 +0300
committerDongjin Kim <tobetter@gmail.com>2020-02-10 16:44:41 +0300
commit40f8e11a587651f14a8386522c0473f7642f5b67 (patch)
treeb4844910fd6a900ad57bf69c3266749cca354411
parentacd2aed7df95c0e57f7d2f9ec6f938a131e60fdf (diff)
downloadu-boot-40f8e11a587651f14a8386522c0473f7642f5b67.tar.xz
ext4: Scan all directory blocks when looking up an entry
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>
-rw-r--r--fs/ext4/ext4_common.c84
1 files changed, 40 insertions, 44 deletions
diff --git a/fs/ext4/ext4_common.c b/fs/ext4/ext4_common.c
index ca566b4f56..71be62e0bf 100644
--- a/fs/ext4/ext4_common.c
+++ b/fs/ext4/ext4_common.c
@@ -533,64 +533,57 @@ 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:
@@ -842,14 +835,17 @@ 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);