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Message-ID: <20131204034757.GC20409@gmail.com> Date: Wed, 4 Dec 2013 11:47:58 +0800 From: Zheng Liu <gnehzuil.liu@...il.com> To: "Darrick J. Wong" <darrick.wong@...cle.com> Cc: linux-ext4@...r.kernel.org, Theodore Ts'o <tytso@....edu>, Zheng Liu <wenqing.lz@...bao.com> Subject: Re: [PATCH v2 17/28] libext2fs: handle inline data in read/write function On Tue, Dec 03, 2013 at 07:02:42PM -0800, Darrick J. Wong wrote: [...] > > +static errcode_t > > +ext2fs_file_read_inline_data(ext2_file_t file, void *buf, > > + unsigned int wanted, unsigned int *got) > > +{ > > + ext2_filsys fs; > > + errcode_t retval; > > + unsigned int start, count = 0; > > + size_t size; > > + > > + fs = file->fs; > > + retval = ext2fs_inline_data_get(fs, file->ino, &file->inode, > > + file->buf, &size); > > + if (retval) > > + return retval; > > + > > + if (file->pos >= size) > > + goto out; > > + > > + start = file->pos % size; > > If file->pos can never be larger than size, this is unnecessary. Good catch! I will fix it soon. Thanks, - Zheng > > > + count = size - start; > > + if (count > wanted) > > + count = wanted; > > + memcpy(buf, file->buf + start, count); > > + file->pos += count; > > + buf += count; > > + > > +out: > > + if (got) > > + *got = count; > > + return retval; > > +} > > + > > + > > errcode_t ext2fs_file_read(ext2_file_t file, void *buf, > > unsigned int wanted, unsigned int *got) > > { > > @@ -236,6 +269,10 @@ errcode_t ext2fs_file_read(ext2_file_t file, void *buf, > > EXT2_CHECK_MAGIC(file, EXT2_ET_MAGIC_EXT2_FILE); > > fs = file->fs; > > > > + /* If an inode has inline data, things get complicated. */ > > + if (file->inode.i_flags & EXT4_INLINE_DATA_FL) > > + return ext2fs_file_read_inline_data(file, buf, wanted, got); > > + > > while ((file->pos < EXT2_I_SIZE(&file->inode)) && (wanted > 0)) { > > retval = sync_buffer_position(file); > > if (retval) > > @@ -266,6 +303,67 @@ fail: > > } > > > > > > +static errcode_t > > +ext2fs_file_write_inline_data(ext2_file_t file, const void *buf, > > + unsigned int nbytes, unsigned int *written) > > +{ > > + ext2_filsys fs; > > + errcode_t retval; > > + unsigned int start, count = 0; > > + size_t size; > > + > > + fs = file->fs; > > + retval = ext2fs_inline_data_get(fs, file->ino, &file->inode, > > + file->buf, &size); > > + if (retval) > > + return retval; > > + > > + if (file->pos < size) { > > + start = file->pos % fs->blocksize; > > Since we're not dealing with blocks, I don't think you need to '%' with the > block size. > > --D > > > + count = nbytes - start; > > + memcpy(file->buf + start, buf, count); > > + > > + retval = ext2fs_inline_data_set(fs, file->ino, &file->inode, > > + file->buf, count); > > + if (retval == EXT2_ET_INLINE_DATA_NO_SPACE) > > + goto expand; > > + if (retval) > > + return retval; > > + > > + file->pos += count; > > + > > + /* Update inode size */ > > + if (count != 0 && EXT2_I_SIZE(&file->inode) < file->pos) { > > + errcode_t rc; > > + > > + rc = ext2fs_file_set_size2(file, file->pos); > > + if (retval == 0) > > + retval = rc; > > + } > > + > > + if (written) > > + *written = count; > > + return 0; > > + } > > + > > +expand: > > + retval = ext2fs_inline_data_expand(fs, file->ino); > > + if (retval) > > + return retval; > > + /* > > + * reload inode and return no space error > > + * > > + * XXX: file->inode could be copied from the outside > > + * in ext2fs_file_open2(). We have no way to modify > > + * the outside inode. > > + */ > > + retval = ext2fs_read_inode(fs, file->ino, &file->inode); > > + if (retval) > > + return retval; > > + return EXT2_ET_INLINE_DATA_NO_SPACE; > > +} > > + > > + > > errcode_t ext2fs_file_write(ext2_file_t file, const void *buf, > > unsigned int nbytes, unsigned int *written) > > { > > @@ -280,6 +378,16 @@ errcode_t ext2fs_file_write(ext2_file_t file, const void *buf, > > if (!(file->flags & EXT2_FILE_WRITE)) > > return EXT2_ET_FILE_RO; > > > > + /* If an inode has inline data, things get complicated. */ > > + if (file->inode.i_flags & EXT4_INLINE_DATA_FL) { > > + retval = ext2fs_file_write_inline_data(file, buf, nbytes, > > + written); > > + if (retval != EXT2_ET_INLINE_DATA_NO_SPACE) > > + return retval; > > + /* fall through to read data from the block */ > > + retval = 0; > > + } > > + > > while (nbytes > 0) { > > retval = sync_buffer_position(file); > > if (retval) > > diff --git a/lib/ext2fs/inline_data.c b/lib/ext2fs/inline_data.c > > index 16af814..4a35209 100644 > > --- a/lib/ext2fs/inline_data.c > > +++ b/lib/ext2fs/inline_data.c > > @@ -309,6 +309,7 @@ errcode_t ext2fs_inline_data_expand(ext2_filsys fs, ext2_ino_t ino) > > struct ext2_inline_data data; > > errcode_t retval; > > blk64_t blk; > > + size_t inline_size; > > char *inline_buf = 0; > > char *blk_buf = 0; > > > > @@ -327,8 +328,8 @@ errcode_t ext2fs_inline_data_expand(ext2_filsys fs, ext2_ino_t ino) > > retval = ext2fs_inline_data_ea_get(&data); > > if (retval) > > return retval; > > - retval = ext2fs_get_mem(EXT4_MIN_INLINE_DATA_SIZE + data.ea_size, > > - &inline_buf); > > + inline_size = data.ea_size + EXT4_MIN_INLINE_DATA_SIZE; > > + retval = ext2fs_get_mem(inline_size, &inline_buf); > > if (retval) > > goto errout; > > > > @@ -347,10 +348,14 @@ errcode_t ext2fs_inline_data_expand(ext2_filsys fs, ext2_ino_t ino) > > if (retval) > > goto errout; > > > > - /* Adjust the rec_len */ > > - retval = ext2fs_inline_data_convert_dir(fs, ino, blk_buf, inline_buf, > > - EXT4_MIN_INLINE_DATA_SIZE + > > - data.ea_size); > > + if (LINUX_S_ISDIR(inode.i_mode)) { > > + /* Adjust the rec_len */ > > + retval = ext2fs_inline_data_convert_dir(fs, ino, blk_buf, > > + inline_buf, inline_size); > > + } else { > > + /* Copy data for a regular inode */ > > + memcpy(blk_buf, inline_buf, inline_size); > > + } > > if (retval) > > goto errout; > > > > @@ -389,3 +394,76 @@ errout: > > ext2fs_free_mem(&data.ea_data); > > return retval; > > } > > + > > +/* > > + * When caller uses this function to retrieve the inline data, it must > > + * allocate a buffer which has the size of inline data. The size of > > + * inline data can be know by ext2fs_inline_data_get_size(). > > + */ > > +errcode_t ext2fs_inline_data_get(ext2_filsys fs, ext2_ino_t ino, > > + struct ext2_inode *inode, > > + void *buf, size_t *size) > > +{ > > + struct ext2_inode inode_buf; > > + struct ext2_inline_data data; > > + errcode_t retval; > > + > > + if (!inode) { > > + retval = ext2fs_read_inode(fs, ino, &inode_buf); > > + if (retval) > > + return retval; > > + inode = &inode_buf; > > + } > > + > > + data.fs = fs; > > + data.ino = ino; > > + retval = ext2fs_inline_data_ea_get(&data); > > + if (retval) > > + return retval; > > + > > + memcpy(buf, (void *)inode->i_block, EXT4_MIN_INLINE_DATA_SIZE); > > + if (data.ea_size > 0) > > + memcpy(buf + EXT4_MIN_INLINE_DATA_SIZE, > > + data.ea_data, data.ea_size); > > + > > + if (size) > > + *size = EXT4_MIN_INLINE_DATA_SIZE + data.ea_size; > > + ext2fs_free_mem(&data.ea_data); > > + return 0; > > +} > > + > > +errcode_t ext2fs_inline_data_set(ext2_filsys fs, ext2_ino_t ino, > > + struct ext2_inode *inode, > > + void *buf, size_t size) > > +{ > > + struct ext2_inode inode_buf; > > + struct ext2_inline_data data; > > + unsigned int max_size = 0; > > + errcode_t retval; > > + > > + if (!inode) { > > + retval = ext2fs_read_inode(fs, ino, &inode_buf); > > + if (retval) > > + return retval; > > + inode = &inode_buf; > > + } > > + > > + /* simple case */ > > + if (size <= EXT4_MIN_INLINE_DATA_SIZE) { > > + memcpy((void *)inode->i_block, buf, size); > > + return ext2fs_write_inode(fs, ino, inode); > > + } > > + > > + /* > > + * complicated case > > + */ > > + memcpy((void *)inode->i_block, buf, EXT4_MIN_INLINE_DATA_SIZE); > > + retval = ext2fs_write_inode(fs, ino, inode); > > + if (retval) > > + return retval; > > + data.fs = fs; > > + data.ino = ino; > > + data.ea_size = size - EXT4_MIN_INLINE_DATA_SIZE; > > + data.ea_data = buf + EXT4_MIN_INLINE_DATA_SIZE; > > + return ext2fs_inline_data_ea_set(&data); > > +} > > -- > > 1.7.9.7 > > > > -- > > To unsubscribe from this list: send the line "unsubscribe linux-ext4" in > > the body of a message to majordomo@...r.kernel.org > > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
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