Commit bb5835ed authored by Theodore Ts'o's avatar Theodore Ts'o
Browse files

ext4: add new ioctl EXT4_IOC_GET_ES_CACHE 



For debugging reasons, it's useful to know the contents of the extent
cache.  Since the extent cache contains much of what is in the fiemap
ioctl, use an fiemap-style interface to return this information.

Signed-off-by: default avatarTheodore Ts'o <tytso@mit.edu>
parent 1ad3ea6e

fs/ext4/ext4.h

+10 −0
Original line number Diff line number Diff line
@@ -652,6 +652,7 @@ enum { 
/* ioctl codes 19--39 are reserved for fscrypt */

#define EXT4_IOC_CLEAR_ES_CACHE		_IO('f', 40)

#define EXT4_IOC_GETSTATE		_IOW('f', 41, __u32)

#define EXT4_IOC_GET_ES_CACHE		_IOWR('f', 42, struct fiemap)



#define EXT4_IOC_FSGETXATTR		FS_IOC_FSGETXATTR

#define EXT4_IOC_FSSETXATTR		FS_IOC_FSSETXATTR
@@ -692,6 +693,12 @@ enum { 
#define EXT4_IOC32_SETVERSION_OLD	FS_IOC32_SETVERSION

#endif



/*

 * Returned by EXT4_IOC_GET_ES_CACHE as an additional possible flag.

 * It indicates that the entry in extent status cache is for a hole.

 */

#define EXT4_FIEMAP_EXTENT_HOLE		0x08000000



/* Max physical block we can address w/o extents */

#define EXT4_MAX_BLOCK_FILE_PHYS	0xFFFFFFFF
@@ -3258,6 +3265,9 @@ extern int ext4_ext_check_inode(struct inode *inode); 
extern ext4_lblk_t ext4_ext_next_allocated_block(struct ext4_ext_path *path);

extern int ext4_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,

			__u64 start, __u64 len);

extern int ext4_get_es_cache(struct inode *inode,

			     struct fiemap_extent_info *fieinfo,

			     __u64 start, __u64 len);

extern int ext4_ext_precache(struct inode *inode);

extern int ext4_collapse_range(struct inode *inode, loff_t offset, loff_t len);

extern int ext4_insert_range(struct inode *inode, loff_t offset, loff_t len);

fs/ext4/extents.c

+86 −8
Original line number Diff line number Diff line
@@ -2315,6 +2315,52 @@ static int ext4_fill_fiemap_extents(struct inode *inode, 
	return err;

}



static int ext4_fill_es_cache_info(struct inode *inode,

				   ext4_lblk_t block, ext4_lblk_t num,

				   struct fiemap_extent_info *fieinfo)

{

	ext4_lblk_t next, end = block + num - 1;

	struct extent_status es;

	unsigned char blksize_bits = inode->i_sb->s_blocksize_bits;

	unsigned int flags;

	int err;



	while (block <= end) {

		next = 0;

		flags = 0;

		if (!ext4_es_lookup_extent(inode, block, &next, &es))

			break;

		if (ext4_es_is_unwritten(&es))

			flags |= FIEMAP_EXTENT_UNWRITTEN;

		if (ext4_es_is_delayed(&es))

			flags |= (FIEMAP_EXTENT_DELALLOC |

				  FIEMAP_EXTENT_UNKNOWN);

		if (ext4_es_is_hole(&es))

			flags |= EXT4_FIEMAP_EXTENT_HOLE;

		if (next == 0)

			flags |= FIEMAP_EXTENT_LAST;

		if (flags & (FIEMAP_EXTENT_DELALLOC|

			     EXT4_FIEMAP_EXTENT_HOLE))

			es.es_pblk = 0;

		else

			es.es_pblk = ext4_es_pblock(&es);

		err = fiemap_fill_next_extent(fieinfo,

				(__u64)es.es_lblk << blksize_bits,

				(__u64)es.es_pblk << blksize_bits,

				(__u64)es.es_len << blksize_bits,

				flags);

		if (next == 0)

			break;

		block = next;

		if (err < 0)

			return err;

		if (err == 1)

			return 0;

	}

	return 0;

}





/*

 * ext4_ext_determine_hole - determine hole around given block

 * @inode:	inode we lookup in
@@ -5017,8 +5063,6 @@ static int ext4_find_delayed_extent(struct inode *inode, 


	return next_del;

}

/* fiemap flags we can handle specified here */

#define EXT4_FIEMAP_FLAGS	(FIEMAP_FLAG_SYNC|FIEMAP_FLAG_XATTR)



static int ext4_xattr_fiemap(struct inode *inode,

				struct fiemap_extent_info *fieinfo)
@@ -5055,10 +5099,16 @@ static int ext4_xattr_fiemap(struct inode *inode, 
	return (error < 0 ? error : 0);

}



int ext4_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,

		__u64 start, __u64 len)

static int _ext4_fiemap(struct inode *inode,

			struct fiemap_extent_info *fieinfo,

			__u64 start, __u64 len,

			int (*fill)(struct inode *, ext4_lblk_t,

				    ext4_lblk_t,

				    struct fiemap_extent_info *))

{

	ext4_lblk_t start_blk;

	u32 ext4_fiemap_flags = FIEMAP_FLAG_SYNC|FIEMAP_FLAG_XATTR;



	int error = 0;



	if (ext4_has_inline_data(inode)) {
@@ -5075,14 +5125,18 @@ int ext4_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo, 
		error = ext4_ext_precache(inode);

		if (error)

			return error;

		fieinfo->fi_flags &= ~FIEMAP_FLAG_CACHE;

	}



	/* fallback to generic here if not in extents fmt */

	if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))

	if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)) &&

	    fill == ext4_fill_fiemap_extents)

		return generic_block_fiemap(inode, fieinfo, start, len,

			ext4_get_block);



	if (fiemap_check_flags(fieinfo, EXT4_FIEMAP_FLAGS))

	if (fill == ext4_fill_es_cache_info)

		ext4_fiemap_flags &= FIEMAP_FLAG_XATTR;

	if (fiemap_check_flags(fieinfo, ext4_fiemap_flags))

		return -EBADR;



	if (fieinfo->fi_flags & FIEMAP_FLAG_XATTR) {
@@ -5101,12 +5155,36 @@ int ext4_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo, 
		 * Walk the extent tree gathering extent information

		 * and pushing extents back to the user.

		 */

		error = ext4_fill_fiemap_extents(inode, start_blk,

						 len_blks, fieinfo);

		error = fill(inode, start_blk, len_blks, fieinfo);

	}

	return error;

}



int ext4_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,

		__u64 start, __u64 len)

{

	return _ext4_fiemap(inode, fieinfo, start, len,

			    ext4_fill_fiemap_extents);

}



int ext4_get_es_cache(struct inode *inode, struct fiemap_extent_info *fieinfo,

		      __u64 start, __u64 len)

{

	if (ext4_has_inline_data(inode)) {

		int has_inline;



		down_read(&EXT4_I(inode)->xattr_sem);

		has_inline = ext4_has_inline_data(inode);

		up_read(&EXT4_I(inode)->xattr_sem);

		if (has_inline)

			return 0;

	}



	return _ext4_fiemap(inode, fieinfo, start, len,

			    ext4_fill_es_cache_info);

}





/*

 * ext4_access_path:

 * Function to access the path buffer for marking it dirty.

fs/ext4/extents_status.c

+10 −0
Original line number Diff line number Diff line
@@ -899,6 +899,7 @@ void ext4_es_cache_extent(struct inode *inode, ext4_lblk_t lblk, 
 * Return: 1 on found, 0 on not

 */

int ext4_es_lookup_extent(struct inode *inode, ext4_lblk_t lblk,

			  ext4_lblk_t *next_lblk,

			  struct extent_status *es)

{

	struct ext4_es_tree *tree;
@@ -948,6 +949,15 @@ int ext4_es_lookup_extent(struct inode *inode, ext4_lblk_t lblk, 
		if (!ext4_es_is_referenced(es1))

			ext4_es_set_referenced(es1);

		stats->es_stats_cache_hits++;

		if (next_lblk) {

			node = rb_next(&es1->rb_node);

			if (node) {

				es1 = rb_entry(node, struct extent_status,

					       rb_node);

				*next_lblk = es1->es_lblk;

			} else

				*next_lblk = 0;

		}

	} else {

		stats->es_stats_cache_misses++;

	}

fs/ext4/extents_status.h

+1 −0
Original line number Diff line number Diff line
@@ -140,6 +140,7 @@ extern void ext4_es_find_extent_range(struct inode *inode, 
				      ext4_lblk_t lblk, ext4_lblk_t end,

				      struct extent_status *es);

extern int ext4_es_lookup_extent(struct inode *inode, ext4_lblk_t lblk,

				 ext4_lblk_t *next_lblk,

				 struct extent_status *es);

extern bool ext4_es_scan_range(struct inode *inode,

			       int (*matching_fn)(struct extent_status *es),

fs/ext4/inode.c

+3 −3
Original line number Diff line number Diff line
@@ -527,7 +527,7 @@ int ext4_map_blocks(handle_t *handle, struct inode *inode, 
		return -EFSCORRUPTED;



	/* Lookup extent status tree firstly */

	if (ext4_es_lookup_extent(inode, map->m_lblk, &es)) {

	if (ext4_es_lookup_extent(inode, map->m_lblk, NULL, &es)) {

		if (ext4_es_is_written(&es) || ext4_es_is_unwritten(&es)) {

			map->m_pblk = ext4_es_pblock(&es) +

					map->m_lblk - es.es_lblk;
@@ -695,7 +695,7 @@ int ext4_map_blocks(handle_t *handle, struct inode *inode, 
		 * extent status tree.

		 */

		if ((flags & EXT4_GET_BLOCKS_PRE_IO) &&

		    ext4_es_lookup_extent(inode, map->m_lblk, &es)) {

		    ext4_es_lookup_extent(inode, map->m_lblk, NULL, &es)) {

			if (ext4_es_is_written(&es))

				goto out_sem;

		}
@@ -1868,7 +1868,7 @@ static int ext4_da_map_blocks(struct inode *inode, sector_t iblock, 
		  (unsigned long) map->m_lblk);



	/* Lookup extent status tree firstly */

	if (ext4_es_lookup_extent(inode, iblock, &es)) {

	if (ext4_es_lookup_extent(inode, iblock, NULL, &es)) {

		if (ext4_es_is_hole(&es)) {

			retval = 0;

			down_read(&EXT4_I(inode)->i_data_sem);