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Commit 7f7670fe authored by Jaegeuk Kim's avatar Jaegeuk Kim
Browse files

f2fs: consider fallocated space for SEEK_DATA 



If an amount of data are allocated though fallocate and user writes a couple of
data among the space, f2fs should return the data offset made by user when
SEEK_DATA is requested.

For example, (N: NEW_ADDR by fallocate, X: NEW_ADDR by user)
1) fallocate 0 ~ 10MB
f -> N N N N N N N N N N N N ... N

2) write 4KB at 5MB offset
f -> N N N N N X N N N N N N ... N

3) SEEK_DATA from 0 should return 5MB offset

So, this patch adds a routine to search the first dirty page to handle that.
Then, the SEEK_DATA flow skips NEW_ADDR offsets until any dirty page is found.

Signed-off-by: default avatarJaegeuk Kim <jaegeuk.kim@samsung.com>
parent fe369bc8

fs/f2fs/file.c

+41 −4
Original line number Diff line number Diff line
@@ -19,6 +19,7 @@ 
#include <linux/compat.h>

#include <linux/uaccess.h>

#include <linux/mount.h>

#include <linux/pagevec.h>



#include "f2fs.h"

#include "node.h"
@@ -194,13 +195,48 @@ int f2fs_sync_file(struct file *file, loff_t start, loff_t end, int datasync) 
	return ret;

}



static pgoff_t __get_first_dirty_index(struct address_space *mapping,

						pgoff_t pgofs, int whence)

{

	struct pagevec pvec;

	int nr_pages;



	if (whence != SEEK_DATA)

		return 0;



	/* find first dirty page index */

	pagevec_init(&pvec, 0);

	nr_pages = pagevec_lookup_tag(&pvec, mapping, &pgofs, PAGECACHE_TAG_DIRTY, 1);

	pgofs = nr_pages ? pvec.pages[0]->index: LONG_MAX;

	pagevec_release(&pvec);

	return pgofs;

}



static bool __found_offset(block_t blkaddr, pgoff_t dirty, pgoff_t pgofs,

							int whence)

{

	switch (whence) {

	case SEEK_DATA:

		if ((blkaddr == NEW_ADDR && dirty == pgofs) ||

			(blkaddr != NEW_ADDR && blkaddr != NULL_ADDR))

			return true;

		break;

	case SEEK_HOLE:

		if (blkaddr == NULL_ADDR)

			return true;

		break;

	}

	return false;

}



static loff_t f2fs_seek_block(struct file *file, loff_t offset, int whence)

{

	struct inode *inode = file->f_mapping->host;

	loff_t maxbytes = inode->i_sb->s_maxbytes;

	struct dnode_of_data dn;

	pgoff_t pgofs, end_offset;

	loff_t data_ofs = offset, isize;

	pgoff_t pgofs, end_offset, dirty;

	loff_t data_ofs = offset;

	loff_t isize;

	int err = 0;



	mutex_lock(&inode->i_mutex);
@@ -218,6 +254,8 @@ static loff_t f2fs_seek_block(struct file *file, loff_t offset, int whence) 


	pgofs = (pgoff_t)(offset >> PAGE_CACHE_SHIFT);



	dirty = __get_first_dirty_index(inode->i_mapping, pgofs, whence);



	for (; data_ofs < isize; data_ofs = pgofs << PAGE_CACHE_SHIFT) {

		set_new_dnode(&dn, inode, NULL, NULL, 0);

		err = get_dnode_of_data(&dn, pgofs, LOOKUP_NODE_RA);
@@ -244,8 +282,7 @@ static loff_t f2fs_seek_block(struct file *file, loff_t offset, int whence) 
			block_t blkaddr;

			blkaddr = datablock_addr(dn.node_page, dn.ofs_in_node);



			if ((whence == SEEK_DATA && blkaddr != NULL_ADDR) ||

				(whence == SEEK_HOLE && blkaddr == NULL_ADDR)) {

			if (__found_offset(blkaddr, dirty, pgofs, whence)) {

				f2fs_put_dnode(&dn);

				goto found;

			}