Unverified Commit 989e2945 authored by Konstantin Komarov's avatar Konstantin Komarov
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fs/ntfs3: improve readahead for bitmap initialization and large directory scans 



Previously sequential reads operations relied solely on single-page reads,
causing the block layer to perform many synchronous I/O requests,
especially for large volumes or large directories. This patch introduces
explicit readahead via page_cache_sync_readahead() and file_ra_state to
reduce I/O latency and improve sequential throughput.

Signed-off-by: default avatarKonstantin Komarov <almaz.alexandrovich@paragon-software.com>
parent 4248f563

fs/ntfs3/bitmap.c

+17 −0
Original line number Diff line number Diff line
@@ -508,6 +508,8 @@ static int wnd_rescan(struct wnd_bitmap *wnd) 
	size_t wpos, wbit, iw, vbo;

	struct buffer_head *bh = NULL;

	CLST lcn, clen;

	struct file_ra_state *ra;

	struct address_space *mapping = sb->s_bdev->bd_mapping;



	wnd->uptodated = 0;

	wnd->extent_max = 0;
@@ -516,6 +518,13 @@ static int wnd_rescan(struct wnd_bitmap *wnd) 


	vbo = 0;



	/* Allocate in memory instead of stack. Not critical if failed. */

	ra = kzalloc(sizeof(*ra), GFP_NOFS);

	if (ra) {

		file_ra_state_init(ra, mapping);

		ra->ra_pages = (wnd->nbits / 8 + PAGE_SIZE - 1) >> PAGE_SHIFT;

	}



	for (iw = 0; iw < wnd->nwnd; iw++) {

		if (iw + 1 == wnd->nwnd)

			wbits = wnd->bits_last;
@@ -552,6 +561,13 @@ static int wnd_rescan(struct wnd_bitmap *wnd) 
			len = ((u64)clen << cluster_bits) - off;

		}



		if (ra) {

			pgoff_t idx = lbo >> PAGE_SHIFT;

			if (!ra_has_index(ra, idx))

				page_cache_sync_readahead(mapping, ra, NULL,

							  idx, 1);

		}



		bh = ntfs_bread(sb, lbo >> sb->s_blocksize_bits);

		if (!bh) {

			err = -EIO;
@@ -638,6 +654,7 @@ static int wnd_rescan(struct wnd_bitmap *wnd) 
	}



out:

	kfree(ra);

	return err;

}

fs/ntfs3/dir.c

+2 −2
Original line number Diff line number Diff line
@@ -487,8 +487,8 @@ static int ntfs_readdir(struct file *file, struct dir_context *ctx) 
			goto out;

		}



		err = indx_read(&ni->dir, ni, bit << ni->dir.idx2vbn_bits,

				&node);

		err = indx_read_ra(&ni->dir, ni, bit << ni->dir.idx2vbn_bits,

				   &node, &file->f_ra);

		if (err)

			goto out;

fs/ntfs3/fslog.c

+4 −2
Original line number Diff line number Diff line
@@ -1074,6 +1074,8 @@ struct ntfs_log { 
	u32 client_undo_commit;



	struct restart_info rst_info, rst_info2;



	struct file_ra_state read_ahead;

};



static inline u32 lsn_to_vbo(struct ntfs_log *log, const u64 lsn)
@@ -1164,8 +1166,8 @@ static int read_log_page(struct ntfs_log *log, u32 vbo, 


	page_buf = page_off ? log->one_page_buf : *buffer;



	err = ntfs_read_run_nb(ni->mi.sbi, &ni->file.run, page_vbo, page_buf,

			       log->page_size, NULL);

	err = ntfs_read_run_nb_ra(ni->mi.sbi, &ni->file.run, page_vbo, page_buf,

				  log->page_size, NULL, &log->read_ahead);

	if (err)

		goto out;

fs/ntfs3/fsntfs.c

+21 −8
Original line number Diff line number Diff line
@@ -1164,11 +1164,13 @@ struct buffer_head *ntfs_bread_run(struct ntfs_sb_info *sbi, 
	return ntfs_bread(sb, lbo >> sb->s_blocksize_bits);

}



int ntfs_read_run_nb(struct ntfs_sb_info *sbi, const struct runs_tree *run,

		     u64 vbo, void *buf, u32 bytes, struct ntfs_buffers *nb)

int ntfs_read_run_nb_ra(struct ntfs_sb_info *sbi, const struct runs_tree *run,

			u64 vbo, void *buf, u32 bytes, struct ntfs_buffers *nb,

			struct file_ra_state *ra)

{

	int err;

	struct super_block *sb = sbi->sb;

	struct address_space *mapping = sb->s_bdev->bd_mapping;

	u32 blocksize = sb->s_blocksize;

	u8 cluster_bits = sbi->cluster_bits;

	u32 off = vbo & sbi->cluster_mask;
@@ -1208,10 +1210,22 @@ int ntfs_read_run_nb(struct ntfs_sb_info *sbi, const struct runs_tree *run, 
		nb->bytes = bytes;

	}



	if (ra && !ra->ra_pages)

		file_ra_state_init(ra, mapping);



	for (;;) {

		u32 len32 = len >= bytes ? bytes : len;

		sector_t block = lbo >> sb->s_blocksize_bits;



		if (ra) {

			pgoff_t index = lbo >> PAGE_SHIFT;

			if (!ra_has_index(ra, index)) {

				page_cache_sync_readahead(mapping, ra, NULL,

							  index, 1);

				ra->prev_pos = (loff_t)index << PAGE_SHIFT;

			}

		}



		do {

			u32 op = blocksize - off;
@@ -1282,11 +1296,11 @@ int ntfs_read_run_nb(struct ntfs_sb_info *sbi, const struct runs_tree *run, 
 *

 * Return: < 0 if error, 0 if ok, -E_NTFS_FIXUP if need to update fixups.

 */

int ntfs_read_bh(struct ntfs_sb_info *sbi, const struct runs_tree *run, u64 vbo,

		 struct NTFS_RECORD_HEADER *rhdr, u32 bytes,

		 struct ntfs_buffers *nb)

int ntfs_read_bh_ra(struct ntfs_sb_info *sbi, const struct runs_tree *run,

		    u64 vbo, struct NTFS_RECORD_HEADER *rhdr, u32 bytes,

		    struct ntfs_buffers *nb, struct file_ra_state *ra)

{

	int err = ntfs_read_run_nb(sbi, run, vbo, rhdr, bytes, nb);

	int err = ntfs_read_run_nb_ra(sbi, run, vbo, rhdr, bytes, nb, ra);



	if (err)

		return err;
@@ -1347,8 +1361,7 @@ int ntfs_get_bh(struct ntfs_sb_info *sbi, const struct runs_tree *run, u64 vbo, 
				wait_on_buffer(bh);



				lock_buffer(bh);

				if (!buffer_uptodate(bh))

				{

				if (!buffer_uptodate(bh)) {

					memset(bh->b_data, 0, blocksize);

					set_buffer_uptodate(bh);

				}

fs/ntfs3/index.c

+7 −6
Original line number Diff line number Diff line
@@ -1026,17 +1026,18 @@ static int indx_write(struct ntfs_index *indx, struct ntfs_inode *ni, 
}



/*

 * indx_read

 * indx_read_ra

 *

 * If ntfs_readdir calls this function

 * inode is shared locked and no ni_lock.

 * Use rw_semaphore for read/write access to alloc_run.

 */

int indx_read(struct ntfs_index *indx, struct ntfs_inode *ni, CLST vbn,

	      struct indx_node **node)

int indx_read_ra(struct ntfs_index *indx, struct ntfs_inode *ni, CLST vbn,

		 struct indx_node **node, struct file_ra_state *ra)

{

	int err;

	struct INDEX_BUFFER *ib;

	struct ntfs_sb_info *sbi = ni->mi.sbi;

	struct runs_tree *run = &indx->alloc_run;

	struct rw_semaphore *lock = &indx->run_lock;

	u64 vbo = (u64)vbn << indx->vbn2vbo_bits;
@@ -1062,7 +1063,7 @@ int indx_read(struct ntfs_index *indx, struct ntfs_inode *ni, CLST vbn, 
	}



	down_read(lock);

	err = ntfs_read_bh(ni->mi.sbi, run, vbo, &ib->rhdr, bytes, &in->nb);

	err = ntfs_read_bh_ra(sbi, run, vbo, &ib->rhdr, bytes, &in->nb, ra);

	up_read(lock);

	if (!err)

		goto ok;
@@ -1082,7 +1083,7 @@ int indx_read(struct ntfs_index *indx, struct ntfs_inode *ni, CLST vbn, 
		goto out;



	down_read(lock);

	err = ntfs_read_bh(ni->mi.sbi, run, vbo, &ib->rhdr, bytes, &in->nb);

	err = ntfs_read_bh_ra(sbi, run, vbo, &ib->rhdr, bytes, &in->nb, ra);

	up_read(lock);

	if (err == -E_NTFS_FIXUP)

		goto ok;
@@ -1098,7 +1099,7 @@ int indx_read(struct ntfs_index *indx, struct ntfs_inode *ni, CLST vbn, 
	}



	if (err == -E_NTFS_FIXUP) {

		ntfs_write_bh(ni->mi.sbi, &ib->rhdr, &in->nb, 0);

		ntfs_write_bh(sbi, &ib->rhdr, &in->nb, 0);

		err = 0;

	}