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Cleanup generic block based fiemap 

This cleans up a few of the complaints of __generic_block_fiemap.  I've
fixed all the typing stuff, used inline functions instead of macros,
gotten rid of a couple of variables, and made sure the size and block
requests are all block aligned.  It also fixes a problem where sometimes
FIEMAP_EXTENT_LAST wasn't being set properly.

Signed-off-by: Josef Bacik <josef@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Josef Bacik 2010-04-23 12:17:17 -04:00 committed by Linus Torvalds
parent 1918ad77f7
commit 3a3076f4d6
2 changed files with 56 additions and 41 deletions
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92
fs/ioctl.c
View File

@ -228,14 +228,23 @@ static int ioctl_fiemap(struct file *filp, unsigned long arg)
#ifdef CONFIG_BLOCK
#define blk_to_logical(inode, blk) (blk << (inode)->i_blkbits)
#define logical_to_blk(inode, offset) (offset >> (inode)->i_blkbits);
static inline sector_t logical_to_blk(struct inode *inode, loff_t offset)
{
return (offset >> inode->i_blkbits);
}
static inline loff_t blk_to_logical(struct inode *inode, sector_t blk)
{
return (blk << inode->i_blkbits);
}
/**
* __generic_block_fiemap - FIEMAP for block based inodes (no locking)
* @inode - the inode to map
* @arg - the pointer to userspace where we copy everything to
* @get_block - the fs's get_block function
* @inode: the inode to map
* @fieinfo: the fiemap info struct that will be passed back to userspace
* @start: where to start mapping in the inode
* @len: how much space to map
* @get_block: the fs's get_block function
*
* This does FIEMAP for block based inodes. Basically it will just loop
* through get_block until we hit the number of extents we want to map, or we
@ -250,58 +259,63 @@ static int ioctl_fiemap(struct file *filp, unsigned long arg)
*/
int __generic_block_fiemap(struct inode *inode,
struct fiemap_extent_info *fieinfo, u64 start,
u64 len, get_block_t *get_block)
struct fiemap_extent_info *fieinfo, loff_t start,
loff_t len, get_block_t *get_block)
{
struct buffer_head tmp;
unsigned long long start_blk;
long long length = 0, map_len = 0;
struct buffer_head map_bh;
sector_t start_blk, last_blk;
loff_t isize = i_size_read(inode);
u64 logical = 0, phys = 0, size = 0;
u32 flags = FIEMAP_EXTENT_MERGED;
int ret = 0, past_eof = 0, whole_file = 0;
bool past_eof = false, whole_file = false;
int ret = 0;
if ((ret = fiemap_check_flags(fieinfo, FIEMAP_FLAG_SYNC)))
ret = fiemap_check_flags(fieinfo, FIEMAP_FLAG_SYNC);
if (ret)
return ret;
/*
* Either the i_mutex or other appropriate locking needs to be held
* since we expect isize to not change at all through the duration of
* this call.
*/
if (len >= isize) {
whole_file = true;
len = isize;
}
start_blk = logical_to_blk(inode, start);
length = (long long)min_t(u64, len, i_size_read(inode));
if (length < len)
whole_file = 1;
map_len = length;
last_blk = logical_to_blk(inode, start + len - 1);
do {
/*
* we set b_size to the total size we want so it will map as
* many contiguous blocks as possible at once
*/
memset(&tmp, 0, sizeof(struct buffer_head));
tmp.b_size = map_len;
memset(&map_bh, 0, sizeof(struct buffer_head));
map_bh.b_size = len;
ret = get_block(inode, start_blk, &tmp, 0);
ret = get_block(inode, start_blk, &map_bh, 0);
if (ret)
break;
/* HOLE */
if (!buffer_mapped(&tmp)) {
length -= blk_to_logical(inode, 1);
if (!buffer_mapped(&map_bh)) {
start_blk++;
/*
* we want to handle the case where there is an
* We want to handle the case where there is an
* allocated block at the front of the file, and then
* nothing but holes up to the end of the file properly,
* to make sure that extent at the front gets properly
* marked with FIEMAP_EXTENT_LAST
*/
if (!past_eof &&
blk_to_logical(inode, start_blk) >=
blk_to_logical(inode, 0)+i_size_read(inode))
blk_to_logical(inode, start_blk) >= isize)
past_eof = 1;
/*
* first hole after going past the EOF, this is our
* First hole after going past the EOF, this is our
* last extent
*/
if (past_eof && size) {
@ -309,15 +323,18 @@ int __generic_block_fiemap(struct inode *inode,
ret = fiemap_fill_next_extent(fieinfo, logical,
phys, size,
flags);
break;
} else if (size) {
ret = fiemap_fill_next_extent(fieinfo, logical,
phys, size, flags);
size = 0;
}
/* if we have holes up to/past EOF then we're done */
if (length <= 0 || past_eof)
if (start_blk > last_blk || past_eof || ret)
break;
} else {
/*
* we have gone over the length of what we wanted to
* We have gone over the length of what we wanted to
* map, and it wasn't the entire file, so add the extent
* we got last time and exit.
*
@ -331,7 +348,7 @@ int __generic_block_fiemap(struct inode *inode,
* are good to go, just add the extent to the fieinfo
* and break
*/
if (length <= 0 && !whole_file) {
if (start_blk > last_blk && !whole_file) {
ret = fiemap_fill_next_extent(fieinfo, logical,
phys, size,
flags);
@ -351,11 +368,10 @@ int __generic_block_fiemap(struct inode *inode,
}
logical = blk_to_logical(inode, start_blk);
phys = blk_to_logical(inode, tmp.b_blocknr);
size = tmp.b_size;
phys = blk_to_logical(inode, map_bh.b_blocknr);
size = map_bh.b_size;
flags = FIEMAP_EXTENT_MERGED;
length -= tmp.b_size;
start_blk += logical_to_blk(inode, size);
/*
@ -363,15 +379,13 @@ int __generic_block_fiemap(struct inode *inode,
* soon as we find a hole that the last extent we found
* is marked with FIEMAP_EXTENT_LAST
*/
if (!past_eof &&
logical+size >=
blk_to_logical(inode, 0)+i_size_read(inode))
past_eof = 1;
if (!past_eof && logical + size >= isize)
past_eof = true;
}
cond_resched();
} while (1);
/* if ret is 1 then we just hit the end of the extent array */
/* If ret is 1 then we just hit the end of the extent array */
if (ret == 1)
ret = 0;

5
include/linux/fs.h
View File

@ -2315,8 +2315,9 @@ extern int vfs_fstatat(int , char __user *, struct kstat *, int);
extern int do_vfs_ioctl(struct file *filp, unsigned int fd, unsigned int cmd,
unsigned long arg);
extern int __generic_block_fiemap(struct inode *inode,
struct fiemap_extent_info *fieinfo, u64 start,
u64 len, get_block_t *get_block);
struct fiemap_extent_info *fieinfo,
loff_t start, loff_t len,
get_block_t *get_block);
extern int generic_block_fiemap(struct inode *inode,
struct fiemap_extent_info *fieinfo, u64 start,
u64 len, get_block_t *get_block);