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Date: Fri, 2 Aug 2013 17:49:36 +0800
From: Zheng Liu <gnehzuil.liu@...il.com>
To: linux-ext4@...r.kernel.org
Cc: Theodore Ts'o <tytso@....edu>, Zheng Liu <wenqing.lz@...bao.com>
Subject: [PATCH v1 09/22] libext2fs: handle inline data in read/write function
From: Zheng Liu <wenqing.lz@...bao.com>
Ext2fs_read/write_inline_data functions copy inline_data from/to
user's buffer directly. When we want to write some data to a file
with inline_data, ext2fs_try_to_write_inline_data is called. In this
function, it firstly check the length of data. If the data can be
saved in inode, this function will create a new extend attribute to
record information of inline_data, and copy all data into this inode.
The following commands in debugfs can handle inline_data feature after
applying this patch:
- dump
- cat
- rdump
- write
Signed-off-by: Theodore Ts'o <tytso@....edu>
Signed-off-by: Zheng Liu <wenqing.lz@...bao.com>
---
lib/ext2fs/ext2_err.et.in | 3 +
lib/ext2fs/ext2fs.h | 7 ++
lib/ext2fs/fileio.c | 19 ++++-
lib/ext2fs/inline_data.c | 179 ++++++++++++++++++++++++++++++++++++++++++++-
4 files changed, 206 insertions(+), 2 deletions(-)
diff --git a/lib/ext2fs/ext2_err.et.in b/lib/ext2fs/ext2_err.et.in
index 8a19cab..9252692 100644
--- a/lib/ext2fs/ext2_err.et.in
+++ b/lib/ext2fs/ext2_err.et.in
@@ -485,4 +485,7 @@ ec EXT2_ET_EXT_ATTR_CURRUPTED,
ec EXT2_ET_BAD_EXTRA_SIZE,
"Bad inode extra isizevalue"
+ec EXT2_ET_INLINE_DATA_NO_SPACE,
+ "No free space in inline data"
+
end
diff --git a/lib/ext2fs/ext2fs.h b/lib/ext2fs/ext2fs.h
index 934dbd0..2804748 100644
--- a/lib/ext2fs/ext2fs.h
+++ b/lib/ext2fs/ext2fs.h
@@ -1359,6 +1359,13 @@ extern errcode_t ext2fs_inline_data_iterate(ext2_filsys fs,
extern errcode_t ext2fs_inline_data_create(ext2_filsys fs,
struct ext2_inode_large *inode,
unsigned int len);
+extern errcode_t ext2fs_read_inline_data(ext2_filsys fs, ext2_ino_t ino,
+ char *buf);
+extern errcode_t ext2fs_write_inline_data(ext2_filsys fs, ext2_ino_t ino,
+ char *buf);
+extern errcode_t ext2fs_try_to_write_inline_data(ext2_filsys fs, ext2_ino_t ino,
+ const void *buf, unsigned int nbytes,
+ unsigned int *written);
/* inode.c */
extern void ext2fs_free_inode_cache(struct ext2_inode_cache *icache);
diff --git a/lib/ext2fs/fileio.c b/lib/ext2fs/fileio.c
index 1f7002c..89c8ea6 100644
--- a/lib/ext2fs/fileio.c
+++ b/lib/ext2fs/fileio.c
@@ -163,7 +163,8 @@ static errcode_t sync_buffer_position(ext2_file_t file)
b = file->pos / file->fs->blocksize;
if (b != file->blockno) {
- retval = ext2fs_file_flush(file);
+ if (!(file->inode.i_flags & EXT4_INLINE_DATA_FL))
+ retval = ext2fs_file_flush(file);
if (retval)
return retval;
file->flags &= ~EXT2_FILE_BUF_VALID;
@@ -186,6 +187,12 @@ static errcode_t load_buffer(ext2_file_t file, int dontfill)
ext2_filsys fs = file->fs;
errcode_t retval;
+ /* We first handle inline_data */
+ if (file->inode.i_flags & EXT4_INLINE_DATA_FL) {
+ retval = ext2fs_read_inline_data(fs, file->ino, file->buf);
+ return retval;
+ }
+
if (!(file->flags & EXT2_FILE_BUF_VALID)) {
retval = ext2fs_bmap2(fs, file->ino, &file->inode,
BMAP_BUFFER, 0, file->blockno, 0,
@@ -280,6 +287,16 @@ errcode_t ext2fs_file_write(ext2_file_t file, const void *buf,
if (!(file->flags & EXT2_FILE_WRITE))
return EXT2_ET_FILE_RO;
+ if (fs->super->s_feature_incompat & EXT4_FEATURE_INCOMPAT_INLINE_DATA) {
+ retval = ext2fs_try_to_write_inline_data(fs, file->ino, buf,
+ nbytes, written);
+ if (!retval)
+ return retval;
+ if (retval != EXT2_ET_INLINE_DATA_NO_SPACE)
+ return retval;
+ 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 c936e28..5ca95ee 100644
--- a/lib/ext2fs/inline_data.c
+++ b/lib/ext2fs/inline_data.c
@@ -21,6 +21,8 @@
static void *ext2fs_get_inline_xattr_pos(struct ext2_inode_large *inode,
struct inline_data *data);
+static unsigned int ext2fs_get_max_inline_size(ext2_filsys fs,
+ struct ext2_inode_large *inode);
static void ext2fs_inline_data_finish_convert(ext2_filsys fs, ext2_ino_t ino,
char *target, char *buf,
int inline_size);
@@ -316,6 +318,74 @@ out:
return retval & BLOCK_ERROR ? ctx->errcode : 0;
}
+errcode_t ext2fs_read_inline_data(ext2_filsys fs, ext2_ino_t ino, char *buf)
+{
+ struct ext2_inode_large *inode;
+ struct inline_data data;
+ errcode_t retval = 0;
+ unsigned int inline_size;
+
+ retval = ext2fs_get_mem(EXT2_INODE_SIZE(fs->super), &inode);
+ if (retval)
+ return retval;
+
+ retval = ext2fs_read_inode_full(fs, ino, (void *)inode,
+ EXT2_INODE_SIZE(fs->super));
+ if (retval)
+ goto err;
+
+ retval = ext2fs_inline_data_find(fs, inode, &data);
+ if (retval)
+ goto err;
+
+ inline_size = data.inline_size;
+
+ memcpy(buf, (void *)inode->i_block, EXT4_MIN_INLINE_DATA_SIZE);
+ if (inline_size > EXT4_MIN_INLINE_DATA_SIZE)
+ memcpy(buf + EXT4_MIN_INLINE_DATA_SIZE,
+ ext2fs_get_inline_xattr_pos(inode, &data),
+ inline_size - EXT4_MIN_INLINE_DATA_SIZE);
+
+err:
+ ext2fs_free_mem(&inode);
+ return retval;
+}
+
+errcode_t ext2fs_write_inline_data(ext2_filsys fs, ext2_ino_t ino, char *buf)
+{
+ struct ext2_inode_large *inode;
+ struct inline_data data;
+ errcode_t retval = 0;
+ unsigned int inline_size;
+
+ retval = ext2fs_get_mem(EXT2_INODE_SIZE(fs->super), &inode);
+ if (retval)
+ return retval;
+
+ retval = ext2fs_read_inode_full(fs, ino, (void *)inode,
+ EXT2_INODE_SIZE(fs->super));
+ if (retval)
+ goto err;
+
+ retval = ext2fs_inline_data_find(fs, inode, &data);
+ if (retval)
+ goto err;
+
+ inline_size = data.inline_size;
+
+ memcpy((void *)inode->i_block, buf, EXT4_MIN_INLINE_DATA_SIZE);
+ if (inline_size > EXT4_MIN_INLINE_DATA_SIZE)
+ memcpy(ext2fs_get_inline_xattr_pos(inode, &data),
+ buf + EXT4_MIN_INLINE_DATA_SIZE,
+ inline_size - EXT4_MIN_INLINE_DATA_SIZE);
+
+ retval = ext2fs_write_inode_full(fs, ino, (void *)inode,
+ EXT2_INODE_SIZE(fs->super));
+err:
+ ext2fs_free_mem(&inode);
+ return retval;
+}
+
errcode_t ext2fs_inline_data_convert(ext2_filsys fs,
ext2_ino_t ino,
void *priv_data)
@@ -430,6 +500,114 @@ out:
return retval;
}
+static unsigned int ext2fs_get_max_inline_size(ext2_filsys fs,
+ struct ext2_inode_large *inode)
+{
+ struct ext2_ext_attr_entry *entry;
+ struct ext2_ext_attr_ibody_header *header;
+ struct inline_data data;
+ errcode_t retval = 0;
+ size_t freesize, min_offs;
+
+ min_offs = EXT2_INODE_SIZE(fs->super) -
+ EXT2_GOOD_OLD_INODE_SIZE -
+ inode->i_extra_isize -
+ sizeof(struct ext2_ext_attr_ibody_header);
+
+ header = IHDR(inode);
+ entry = IFIRST(header);
+
+ for (; !EXT2_EXT_IS_LAST_ENTRY(entry);
+ entry = EXT2_EXT_ATTR_NEXT(entry)) {
+ if (!entry->e_value_block && entry->e_value_size) {
+ size_t offs = entry->e_value_offs;
+ if (offs < min_offs)
+ min_offs = offs;
+ }
+ }
+ freesize = min_offs -
+ ((char *)entry - (char *)IFIRST(header)) - sizeof(__u32);
+
+ /*
+ * We try to get inline data offset, but maybe it doesn't be
+ * created. So we ignore this error.
+ */
+ retval = ext2fs_inline_data_find(fs, inode, &data);
+ if (retval && retval != EXT2_ET_BAD_EXT_ATTR_MAGIC)
+ return 0;
+
+ if (data.inline_off) {
+ entry = (struct ext2_ext_attr_entry *)
+ ((char *)inode + data.inline_off);
+ freesize += entry->e_value_size;
+ goto out;
+ }
+
+ freesize -= EXT2_EXT_ATTR_LEN(strlen(EXT4_EXT_ATTR_SYSTEM_DATA));
+
+ if (freesize > EXT2_EXT_ATTR_ROUND)
+ freesize = EXT2_EXT_ATTR_SIZE(freesize - EXT2_EXT_ATTR_ROUND);
+ else
+ freesize = 0;
+
+out:
+ return freesize + EXT4_MIN_INLINE_DATA_SIZE;
+}
+
+errcode_t ext2fs_try_to_write_inline_data(ext2_filsys fs, ext2_ino_t ino,
+ const void *buf, unsigned int nbytes,
+ unsigned int *written)
+{
+ struct ext2_inode_large *inode;
+ struct inline_data data;
+ errcode_t retval = 0;
+ unsigned int inline_size = 0;
+
+ retval = ext2fs_get_mem(EXT2_INODE_SIZE(fs->super), &inode);
+ if (retval)
+ return retval;
+ retval = ext2fs_read_inode_full(fs, ino, (void *)inode,
+ EXT2_INODE_SIZE(fs->super));
+ if (retval)
+ goto out;
+
+ if (nbytes > ext2fs_get_max_inline_size(fs, inode)) {
+ retval = EXT2_ET_INLINE_DATA_NO_SPACE;
+ goto out;
+ }
+
+ retval = ext2fs_inline_data_create(fs, inode, nbytes);
+ if (retval)
+ goto out;
+
+ retval = ext2fs_inline_data_find(fs, inode, &data);
+ if (retval)
+ goto out;
+
+ inline_size = data.inline_size;
+
+ memcpy((void *)inode->i_block, buf, EXT4_MIN_INLINE_DATA_SIZE);
+ if (inline_size > EXT4_MIN_INLINE_DATA_SIZE)
+ memcpy(ext2fs_get_inline_xattr_pos(inode, &data),
+ (const char *) buf + EXT4_MIN_INLINE_DATA_SIZE,
+ inline_size - EXT4_MIN_INLINE_DATA_SIZE);
+
+ inode->i_flags &= ~EXT4_EXTENTS_FL;
+ inode->i_flags |= EXT4_INLINE_DATA_FL;
+
+ retval = ext2fs_write_inode_full(fs, ino, (void *)inode,
+ EXT2_INODE_SIZE(fs->super));
+
+ if (!retval)
+ *written = nbytes;
+ else
+ *written = 0;
+
+out:
+ ext2fs_free_mem(&inode);
+ return retval;
+}
+
errcode_t ext2fs_inline_data_create(ext2_filsys fs,
struct ext2_inode_large *inode,
unsigned int len)
@@ -442,7 +620,6 @@ errcode_t ext2fs_inline_data_create(ext2_filsys fs,
.name_index = EXT4_EXT_ATTR_INDEX_SYSTEM,
.name = EXT4_EXT_ATTR_SYSTEM_DATA,
};
- void *buf;
errcode_t retval;
if (len > EXT4_MIN_INLINE_DATA_SIZE) {
--
1.7.9.7
--
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