ext4: store maxbytes for bitmapped files and return EFBIG as appropriate

Calculate & store the max offset for bitmapped files, and
catch too-large seeks, truncates, and writes in ext4, shortening
or rejecting as appropriate.

Signed-off-by: Eric Sandeen <sandeen@redhat.com>

diff --git a/fs/ext4/file.c b/fs/ext4/file.c
index 1a81cd66d63b2b2371e4c35025f004657ca66adf..a6b2aa14626eaadcdd7334367f3898af26a3caab 100644 (file)
--- a/fs/ext4/file.c
+++ b/fs/ext4/file.c
@@ -56,8 +56,25 @@ ext4_file_write(struct kiocb *iocb, const struct iovec *iov,
        ssize_t ret;
        int err;
 
-       ret = generic_file_aio_write(iocb, iov, nr_segs, pos);
+       /*
+        * If we have encountered a bitmap-format file, the size limit
+        * is smaller than s_maxbytes, which is for extent-mapped files.
+        */
+
+       if (!(EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL)) {
+               struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
+               size_t length = iov_length(iov, nr_segs);
 
+               if (pos > sbi->s_bitmap_maxbytes)
+                       return -EFBIG;
+
+               if (pos + length > sbi->s_bitmap_maxbytes) {
+                       nr_segs = iov_shorten((struct iovec *)iov, nr_segs,
+                                             sbi->s_bitmap_maxbytes - pos);
+               }
+       }
+
+       ret = generic_file_aio_write(iocb, iov, nr_segs, pos);
        /*
         * Skip flushing if there was an error, or if nothing was written.
         */

diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 9cf85721d83cfbd2819d9bc8915fea0fb1818598..eaace1373ccb11cda8e113662ad0375b91e3832f 100644 (file)
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -314,7 +314,10 @@ static int ext4_block_to_path(struct inode *inode,
                offsets[n++] = i_block & (ptrs - 1);
                final = ptrs;
        } else {
-               ext4_warning(inode->i_sb, "ext4_block_to_path", "block > big");
+               ext4_warning(inode->i_sb, "ext4_block_to_path",
+                               "block %u > max",
+                               i_block + direct_blocks +
+                               indirect_blocks + double_blocks);
        }
        if (boundary)
                *boundary = final - 1 - (i_block & (ptrs - 1));
@@ -3092,6 +3095,17 @@ int ext4_setattr(struct dentry *dentry, struct iattr *attr)
                ext4_journal_stop(handle);
        }
 
+       if (attr->ia_valid & ATTR_SIZE) {
+               if (!(EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL)) {
+                       struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
+
+                       if (attr->ia_size > sbi->s_bitmap_maxbytes) {
+                               error = -EFBIG;
+                               goto err_out;
+                       }
+               }
+       }
+
        if (S_ISREG(inode->i_mode) &&
            attr->ia_valid & ATTR_SIZE && attr->ia_size < inode->i_size) {
                handle_t *handle;

diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index c79e46b7f15901faa7ee32a6d8ef1c1de99510b4..0931831537a2f7ea334b18fe2a69e6403828c879 100644 (file)
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -1922,6 +1922,7 @@ static int ext4_fill_super (struct super_block *sb, void *data, int silent)
                }
        }
 
+       sbi->s_bitmap_maxbytes = ext4_max_bitmap_size(sb->s_blocksize_bits);
        sb->s_maxbytes = ext4_max_size(sb->s_blocksize_bits);
 
        if (le32_to_cpu(es->s_rev_level) == EXT4_GOOD_OLD_REV) {

diff --git a/include/linux/ext4_fs_sb.h b/include/linux/ext4_fs_sb.h
index f15821c5e4c4558610c46d80f5bc4a5503c045c9..38a47ec06df9507431263c315d98b6d0a94e1d23 100644 (file)
--- a/include/linux/ext4_fs_sb.h
+++ b/include/linux/ext4_fs_sb.h
@@ -38,6 +38,7 @@ struct ext4_sb_info {
        ext4_group_t s_groups_count;    /* Number of groups in the fs */
        unsigned long s_overhead_last;  /* Last calculated overhead */
        unsigned long s_blocks_last;    /* Last seen block count */
+       loff_t s_bitmap_maxbytes;       /* max bytes for bitmap files */
        struct buffer_head * s_sbh;     /* Buffer containing the super block */
        struct ext4_super_block * s_es; /* Pointer to the super block in the buffer */
        struct buffer_head ** s_group_desc;