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Commit 2ccb5fb9 authored by Aneesh Kumar K.V's avatar Aneesh Kumar K.V Committed by Theodore Ts'o
Browse files

ext4: Use new buffer_head flag to check uninit group bitmaps initialization 



For uninit block group, the on-disk bitmap is not initialized. That
implies we cannot depend on the uptodate flag on the bitmap
buffer_head to find bitmap validity.  Use a new buffer_head flag which
would be set after we properly initialize the bitmap.  This also
prevents (re-)initializing the uninit group bitmap every time we call 
ext4_read_block_bitmap().

Signed-off-by: default avatarAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: default avatar"Theodore Ts'o" <tytso@mit.edu>
Cc: stable@kernel.org
parent 39341867

fs/ext4/balloc.c

+23 −2
Original line number Diff line number Diff line
@@ -320,20 +320,41 @@ ext4_read_block_bitmap(struct super_block *sb, ext4_group_t block_group) 
			    block_group, bitmap_blk);

		return NULL;

	}

	if (buffer_uptodate(bh) &&

	    !(desc->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT)))



	if (bitmap_uptodate(bh))

		return bh;



	lock_buffer(bh);

	if (bitmap_uptodate(bh)) {

		unlock_buffer(bh);

		return bh;

	}

	spin_lock(sb_bgl_lock(EXT4_SB(sb), block_group));

	if (desc->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT)) {

		ext4_init_block_bitmap(sb, bh, block_group, desc);

		set_bitmap_uptodate(bh);

		set_buffer_uptodate(bh);

		spin_unlock(sb_bgl_lock(EXT4_SB(sb), block_group));

		unlock_buffer(bh);

		return bh;

	}

	spin_unlock(sb_bgl_lock(EXT4_SB(sb), block_group));

	if (buffer_uptodate(bh)) {

		/*

		 * if not uninit if bh is uptodate,

		 * bitmap is also uptodate

		 */

		set_bitmap_uptodate(bh);

		unlock_buffer(bh);

		return bh;

	}

	/*

	 * submit the buffer_head for read. We can

	 * safely mark the bitmap as uptodate now.

	 * We do it here so the bitmap uptodate bit

	 * get set with buffer lock held.

	 */

	set_bitmap_uptodate(bh);

	if (bh_submit_read(bh) < 0) {

		put_bh(bh);

		ext4_error(sb, __func__,

fs/ext4/ext4.h

+18 −0
Original line number Diff line number Diff line
@@ -19,6 +19,7 @@ 
#include <linux/types.h>

#include <linux/blkdev.h>

#include <linux/magic.h>

#include <linux/jbd2.h>

#include "ext4_i.h"



/*
@@ -1352,6 +1353,23 @@ extern int ext4_get_blocks_wrap(handle_t *handle, struct inode *inode, 
extern int ext4_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,

			__u64 start, __u64 len);



/*

 * Add new method to test wether block and inode bitmaps are properly

 * initialized. With uninit_bg reading the block from disk is not enough

 * to mark the bitmap uptodate. We need to also zero-out the bitmap

 */

#define BH_BITMAP_UPTODATE BH_JBDPrivateStart



static inline int bitmap_uptodate(struct buffer_head *bh)

{

	return (buffer_uptodate(bh) &&

			test_bit(BH_BITMAP_UPTODATE, &(bh)->b_state));

}

static inline void set_bitmap_uptodate(struct buffer_head *bh)

{

	set_bit(BH_BITMAP_UPTODATE, &(bh)->b_state);

}



#endif	/* __KERNEL__ */



#endif	/* _EXT4_H */

fs/ext4/ialloc.c

+22 −2
Original line number Diff line number Diff line
@@ -115,20 +115,40 @@ ext4_read_inode_bitmap(struct super_block *sb, ext4_group_t block_group) 
			    block_group, bitmap_blk);

		return NULL;

	}

	if (buffer_uptodate(bh) &&

	    !(desc->bg_flags & cpu_to_le16(EXT4_BG_INODE_UNINIT)))

	if (bitmap_uptodate(bh))

		return bh;



	lock_buffer(bh);

	if (bitmap_uptodate(bh)) {

		unlock_buffer(bh);

		return bh;

	}

	spin_lock(sb_bgl_lock(EXT4_SB(sb), block_group));

	if (desc->bg_flags & cpu_to_le16(EXT4_BG_INODE_UNINIT)) {

		ext4_init_inode_bitmap(sb, bh, block_group, desc);

		set_bitmap_uptodate(bh);

		set_buffer_uptodate(bh);

		spin_unlock(sb_bgl_lock(EXT4_SB(sb), block_group));

		unlock_buffer(bh);

		return bh;

	}

	spin_unlock(sb_bgl_lock(EXT4_SB(sb), block_group));

	if (buffer_uptodate(bh)) {

		/*

		 * if not uninit if bh is uptodate,

		 * bitmap is also uptodate

		 */

		set_bitmap_uptodate(bh);

		unlock_buffer(bh);

		return bh;

	}

	/*

	 * submit the buffer_head for read. We can

	 * safely mark the bitmap as uptodate now.

	 * We do it here so the bitmap uptodate bit

	 * get set with buffer lock held.

	 */

	set_bitmap_uptodate(bh);

	if (bh_submit_read(bh) < 0) {

		put_bh(bh);

		ext4_error(sb, __func__,

fs/ext4/mballoc.c

+22 −2
Original line number Diff line number Diff line
@@ -794,22 +794,42 @@ static int ext4_mb_init_cache(struct page *page, char *incore) 
		if (bh[i] == NULL)

			goto out;



		if (buffer_uptodate(bh[i]) &&

		    !(desc->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT)))

		if (bitmap_uptodate(bh[i]))

			continue;



		lock_buffer(bh[i]);

		if (bitmap_uptodate(bh[i])) {

			unlock_buffer(bh[i]);

			continue;

		}

		spin_lock(sb_bgl_lock(EXT4_SB(sb), first_group + i));

		if (desc->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT)) {

			ext4_init_block_bitmap(sb, bh[i],

						first_group + i, desc);

			set_bitmap_uptodate(bh[i]);

			set_buffer_uptodate(bh[i]);

			spin_unlock(sb_bgl_lock(EXT4_SB(sb), first_group + i));

			unlock_buffer(bh[i]);

			continue;

		}

		spin_unlock(sb_bgl_lock(EXT4_SB(sb), first_group + i));

		if (buffer_uptodate(bh[i])) {

			/*

			 * if not uninit if bh is uptodate,

			 * bitmap is also uptodate

			 */

			set_bitmap_uptodate(bh[i]);

			unlock_buffer(bh[i]);

			continue;

		}

		get_bh(bh[i]);

		/*

		 * submit the buffer_head for read. We can

		 * safely mark the bitmap as uptodate now.

		 * We do it here so the bitmap uptodate bit

		 * get set with buffer lock held.

		 */

		set_bitmap_uptodate(bh[i]);

		bh[i]->b_end_io = end_buffer_read_sync;

		submit_bh(READ, bh[i]);

		mb_debug("read bitmap for group %u\n", first_group + i);