提交 6873fa0d 编写于 作者: E Eric Sandeen 提交者: Theodore Ts'o

Hook ext4 to the vfs fiemap interface.

ext4_ext_walk_space() was reinstated to be used for iterating over file
extents with a callback; it is used by the ext4 fiemap implementation.
Signed-off-by: NEric Sandeen <sandeen@redhat.com>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>
Cc: linux-ext4@vger.kernel.org
Cc: linux-fsdevel@vger.kernel.org
上级 68c9d702
......@@ -1067,6 +1067,8 @@ struct buffer_head *ext4_getblk(handle_t *, struct inode *,
ext4_lblk_t, int, int *);
struct buffer_head *ext4_bread(handle_t *, struct inode *,
ext4_lblk_t, int, int *);
int ext4_get_block(struct inode *inode, sector_t iblock,
struct buffer_head *bh_result, int create);
int ext4_get_blocks_handle(handle_t *handle, struct inode *inode,
ext4_lblk_t iblock, unsigned long maxblocks,
struct buffer_head *bh_result,
......
......@@ -124,6 +124,19 @@ struct ext4_ext_path {
#define EXT4_EXT_CACHE_GAP 1
#define EXT4_EXT_CACHE_EXTENT 2
/*
* to be called by ext4_ext_walk_space()
* negative retcode - error
* positive retcode - signal for ext4_ext_walk_space(), see below
* callback must return valid extent (passed or newly created)
*/
typedef int (*ext_prepare_callback)(struct inode *, struct ext4_ext_path *,
struct ext4_ext_cache *,
struct ext4_extent *, void *);
#define EXT_CONTINUE 0
#define EXT_BREAK 1
#define EXT_REPEAT 2
#define EXT_MAX_BLOCK 0xffffffff
......@@ -224,6 +237,8 @@ extern int ext4_ext_try_to_merge(struct inode *inode,
struct ext4_extent *);
extern unsigned int ext4_ext_check_overlap(struct inode *, struct ext4_extent *, struct ext4_ext_path *);
extern int ext4_ext_insert_extent(handle_t *, struct inode *, struct ext4_ext_path *, struct ext4_extent *);
extern int ext4_ext_walk_space(struct inode *, ext4_lblk_t, ext4_lblk_t,
ext_prepare_callback, void *);
extern struct ext4_ext_path *ext4_ext_find_extent(struct inode *, ext4_lblk_t,
struct ext4_ext_path *);
extern int ext4_ext_search_left(struct inode *, struct ext4_ext_path *,
......
......@@ -40,6 +40,7 @@
#include <linux/slab.h>
#include <linux/falloc.h>
#include <asm/uaccess.h>
#include <linux/fiemap.h>
#include "ext4_jbd2.h"
#include "ext4_extents.h"
......@@ -1626,6 +1627,113 @@ int ext4_ext_insert_extent(handle_t *handle, struct inode *inode,
return err;
}
int ext4_ext_walk_space(struct inode *inode, ext4_lblk_t block,
ext4_lblk_t num, ext_prepare_callback func,
void *cbdata)
{
struct ext4_ext_path *path = NULL;
struct ext4_ext_cache cbex;
struct ext4_extent *ex;
ext4_lblk_t next, start = 0, end = 0;
ext4_lblk_t last = block + num;
int depth, exists, err = 0;
BUG_ON(func == NULL);
BUG_ON(inode == NULL);
while (block < last && block != EXT_MAX_BLOCK) {
num = last - block;
/* find extent for this block */
path = ext4_ext_find_extent(inode, block, path);
if (IS_ERR(path)) {
err = PTR_ERR(path);
path = NULL;
break;
}
depth = ext_depth(inode);
BUG_ON(path[depth].p_hdr == NULL);
ex = path[depth].p_ext;
next = ext4_ext_next_allocated_block(path);
exists = 0;
if (!ex) {
/* there is no extent yet, so try to allocate
* all requested space */
start = block;
end = block + num;
} else if (le32_to_cpu(ex->ee_block) > block) {
/* need to allocate space before found extent */
start = block;
end = le32_to_cpu(ex->ee_block);
if (block + num < end)
end = block + num;
} else if (block >= le32_to_cpu(ex->ee_block)
+ ext4_ext_get_actual_len(ex)) {
/* need to allocate space after found extent */
start = block;
end = block + num;
if (end >= next)
end = next;
} else if (block >= le32_to_cpu(ex->ee_block)) {
/*
* some part of requested space is covered
* by found extent
*/
start = block;
end = le32_to_cpu(ex->ee_block)
+ ext4_ext_get_actual_len(ex);
if (block + num < end)
end = block + num;
exists = 1;
} else {
BUG();
}
BUG_ON(end <= start);
if (!exists) {
cbex.ec_block = start;
cbex.ec_len = end - start;
cbex.ec_start = 0;
cbex.ec_type = EXT4_EXT_CACHE_GAP;
} else {
cbex.ec_block = le32_to_cpu(ex->ee_block);
cbex.ec_len = ext4_ext_get_actual_len(ex);
cbex.ec_start = ext_pblock(ex);
cbex.ec_type = EXT4_EXT_CACHE_EXTENT;
}
BUG_ON(cbex.ec_len == 0);
err = func(inode, path, &cbex, ex, cbdata);
ext4_ext_drop_refs(path);
if (err < 0)
break;
if (err == EXT_REPEAT)
continue;
else if (err == EXT_BREAK) {
err = 0;
break;
}
if (ext_depth(inode) != depth) {
/* depth was changed. we have to realloc path */
kfree(path);
path = NULL;
}
block = cbex.ec_block + cbex.ec_len;
}
if (path) {
ext4_ext_drop_refs(path);
kfree(path);
}
return err;
}
static void
ext4_ext_put_in_cache(struct inode *inode, ext4_lblk_t block,
__u32 len, ext4_fsblk_t start, int type)
......@@ -2971,3 +3079,143 @@ long ext4_fallocate(struct inode *inode, int mode, loff_t offset, loff_t len)
mutex_unlock(&inode->i_mutex);
return ret > 0 ? ret2 : ret;
}
/*
* Callback function called for each extent to gather FIEMAP information.
*/
int ext4_ext_fiemap_cb(struct inode *inode, struct ext4_ext_path *path,
struct ext4_ext_cache *newex, struct ext4_extent *ex,
void *data)
{
struct fiemap_extent_info *fieinfo = data;
unsigned long blksize_bits = inode->i_sb->s_blocksize_bits;
__u64 logical;
__u64 physical;
__u64 length;
__u32 flags = 0;
int error;
logical = (__u64)newex->ec_block << blksize_bits;
if (newex->ec_type == EXT4_EXT_CACHE_GAP) {
pgoff_t offset;
struct page *page;
struct buffer_head *bh = NULL;
offset = logical >> PAGE_SHIFT;
page = find_get_page(inode->i_mapping, offset);
if (!page || !page_has_buffers(page))
return EXT_CONTINUE;
bh = page_buffers(page);
if (!bh)
return EXT_CONTINUE;
if (buffer_delay(bh)) {
flags |= FIEMAP_EXTENT_DELALLOC;
page_cache_release(page);
} else {
page_cache_release(page);
return EXT_CONTINUE;
}
}
physical = (__u64)newex->ec_start << blksize_bits;
length = (__u64)newex->ec_len << blksize_bits;
if (ex && ext4_ext_is_uninitialized(ex))
flags |= FIEMAP_EXTENT_UNWRITTEN;
/*
* If this extent reaches EXT_MAX_BLOCK, it must be last.
*
* Or if ext4_ext_next_allocated_block is EXT_MAX_BLOCK,
* this also indicates no more allocated blocks.
*
* XXX this might miss a single-block extent at EXT_MAX_BLOCK
*/
if (logical + length - 1 == EXT_MAX_BLOCK ||
ext4_ext_next_allocated_block(path) == EXT_MAX_BLOCK)
flags |= FIEMAP_EXTENT_LAST;
error = fiemap_fill_next_extent(fieinfo, logical, physical,
length, flags);
if (error < 0)
return error;
if (error == 1)
return EXT_BREAK;
return EXT_CONTINUE;
}
/* fiemap flags we can handle specified here */
#define EXT4_FIEMAP_FLAGS (FIEMAP_FLAG_SYNC|FIEMAP_FLAG_XATTR)
int ext4_xattr_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo)
{
__u64 physical = 0;
__u64 length;
__u32 flags = FIEMAP_EXTENT_LAST;
int blockbits = inode->i_sb->s_blocksize_bits;
int error = 0;
/* in-inode? */
if (EXT4_I(inode)->i_state & EXT4_STATE_XATTR) {
struct ext4_iloc iloc;
int offset; /* offset of xattr in inode */
error = ext4_get_inode_loc(inode, &iloc);
if (error)
return error;
physical = iloc.bh->b_blocknr << blockbits;
offset = EXT4_GOOD_OLD_INODE_SIZE +
EXT4_I(inode)->i_extra_isize;
physical += offset;
length = EXT4_SB(inode->i_sb)->s_inode_size - offset;
flags |= FIEMAP_EXTENT_DATA_INLINE;
} else { /* external block */
physical = EXT4_I(inode)->i_file_acl << blockbits;
length = inode->i_sb->s_blocksize;
}
if (physical)
error = fiemap_fill_next_extent(fieinfo, 0, physical,
length, flags);
return (error < 0 ? error : 0);
}
int ext4_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
__u64 start, __u64 len)
{
ext4_lblk_t start_blk;
ext4_lblk_t len_blks;
int error = 0;
/* fallback to generic here if not in extents fmt */
if (!(EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL))
return generic_block_fiemap(inode, fieinfo, start, len,
ext4_get_block);
if (fiemap_check_flags(fieinfo, EXT4_FIEMAP_FLAGS))
return -EBADR;
if (fieinfo->fi_flags & FIEMAP_FLAG_XATTR) {
error = ext4_xattr_fiemap(inode, fieinfo);
} else {
start_blk = start >> inode->i_sb->s_blocksize_bits;
len_blks = len >> inode->i_sb->s_blocksize_bits;
/*
* Walk the extent tree gathering extent information.
* ext4_ext_fiemap_cb will push extents back to user.
*/
down_write(&EXT4_I(inode)->i_data_sem);
error = ext4_ext_walk_space(inode, start_blk, len_blks,
ext4_ext_fiemap_cb, fieinfo);
up_write(&EXT4_I(inode)->i_data_sem);
}
return error;
}
......@@ -140,6 +140,9 @@ static int ext4_file_mmap(struct file *file, struct vm_area_struct *vma)
return 0;
}
extern int ext4_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
__u64 start, __u64 len);
const struct file_operations ext4_file_operations = {
.llseek = generic_file_llseek,
.read = do_sync_read,
......@@ -170,5 +173,6 @@ const struct inode_operations ext4_file_inode_operations = {
#endif
.permission = ext4_permission,
.fallocate = ext4_fallocate,
.fiemap = ext4_fiemap,
};
......@@ -1135,8 +1135,8 @@ int ext4_get_blocks_wrap(handle_t *handle, struct inode *inode, sector_t block,
/* Maximum number of blocks we map for direct IO at once. */
#define DIO_MAX_BLOCKS 4096
static int ext4_get_block(struct inode *inode, sector_t iblock,
struct buffer_head *bh_result, int create)
int ext4_get_block(struct inode *inode, sector_t iblock,
struct buffer_head *bh_result, int create)
{
handle_t *handle = ext4_journal_current_handle();
int ret = 0, started = 0;
......
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