This patch keeps getting lost, so I'm posting it again. Andrew has complained
several times about the format of this function, the type'ing used and such, so
this patch fixes all of this. Also it addresses 2 issues
1) Some filesystems (gfs2) do not like being given non-block-aligned b_size's to
map, so make sure we block align the b_size.
2) If you have a file with say 50 blocks, and ask to map 25 of those blocks, and
block 23 is a hole and block 24 is data, block 24 will get dropped. This fixes
the problem by making sure we add the extent to the fieinfo before returning.
I've tested this patch with my fiemap-tester, and it runs fine. I also tested
with a file that was < blocksize (which is where gfs2 was having problems) and
it worked fine. I also tested this with a 1 terabyte file, and it worked fine.
Signed-off-by: Josef Bacik <josef@xxxxxxxxxx>
---
fs/ioctl.c | 88 ++++++++++++++++++++++++++++++++-------------------
include/linux/fs.h | 5 ++-
2 files changed, 58 insertions(+), 35 deletions(-)
diff --git a/fs/ioctl.c b/fs/ioctl.c
index 6c75110..4ebdc41 100644
--- a/fs/ioctl.c
+++ b/fs/ioctl.c
@@ -228,13 +228,22 @@ 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
+ * @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
@@ -250,46 +259,55 @@ 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;
+ loff_t map_end;
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;
start_blk = logical_to_blk(inode, start);
- length = (long long)min_t(u64, len, i_size_read(inode));
- if (length < len)
- whole_file = 1;
+ if (len >= i_size_read(inode)) {
+ whole_file = true;
+ len = i_size_read(inode);
+ }
- map_len = length;
+ /*
+ * Some filesystems (gfs2) don't deal with being told to map lengths
+ * that are not blocksize aligned, so make the length blocksized
+ * aligned, since b_size should always just come back as the real len.
+ */
+ len = (len + (1 << inode->i_blkbits) - 1) &
+ ~((1 << inode->i_blkbits) - 1);
+ map_end = start + len;
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
@@ -297,11 +315,11 @@ int __generic_block_fiemap(struct inode *inode,
*/
if (!past_eof &&
blk_to_logical(inode, start_blk) >=
- blk_to_logical(inode, 0)+i_size_read(inode))
+ blk_to_logical(inode, 0) + i_size_read(inode))
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 +327,19 @@ 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 (blk_to_logical(inode, start_blk) > map_end ||
+ 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 +353,8 @@ 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 (blk_to_logical(inode, start_blk) > map_end &&
+ !whole_file) {
ret = fiemap_fill_next_extent(fieinfo, logical,
phys, size,
flags);
@@ -351,11 +374,10 @@ 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);
/*
@@ -364,14 +386,14 @@ int __generic_block_fiemap(struct inode *inode,
* is marked with FIEMAP_EXTENT_LAST
*/
if (!past_eof &&
- logical+size >=
- blk_to_logical(inode, 0)+i_size_read(inode))
- past_eof = 1;
+ logical + size >=
+ blk_to_logical(inode, 0) + i_size_read(inode))
+ 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;
diff --git a/include/linux/fs.h b/include/linux/fs.h
index ebb1cd5..7e6e47f 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -2313,8 +2313,9 @@ 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);
--
1.6.5.rc2
--
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