#include <linux/ext4_fs.h>
/*
- * with AGRESSIVE_TEST defined capacity of index/leaf blocks
- * become very little, so index split, in-depth growing and
- * other hard changes happens much more often
- * this is for debug purposes only
+ * With AGGRESSIVE_TEST defined, the capacity of index/leaf blocks
+ * becomes very small, so index split, in-depth growing and
+ * other hard changes happen much more often.
+ * This is for debug purposes only.
*/
-#define AGRESSIVE_TEST_
+#define AGGRESSIVE_TEST_
/*
- * with EXTENTS_STATS defined number of blocks and extents
- * are collected in truncate path. they'll be showed at
- * umount time
+ * With EXTENTS_STATS defined, the number of blocks and extents
+ * are collected in the truncate path. They'll be shown at
+ * umount time.
*/
#define EXTENTS_STATS__
/*
- * if CHECK_BINSEARCH defined, then results of binary search
- * will be checked by linear search
+ * If CHECK_BINSEARCH is defined, then the results of the binary search
+ * will also be checked by linear search.
*/
#define CHECK_BINSEARCH__
/*
- * if EXT_DEBUG is defined you can use 'extdebug' mount option
- * to get lots of info what's going on
+ * If EXT_DEBUG is defined you can use the 'extdebug' mount option
+ * to get lots of info about what's going on.
*/
#define EXT_DEBUG__
#ifdef EXT_DEBUG
#endif
/*
- * if EXT_STATS is defined then stats numbers are collected
- * these number will be displayed at umount time
+ * If EXT_STATS is defined then stats numbers are collected.
+ * These number will be displayed at umount time.
*/
#define EXT_STATS_
/*
- * ext4_inode has i_block array (60 bytes total)
- * first 12 bytes store ext4_extent_header
- * the remain stores array of ext4_extent
+ * ext4_inode has i_block array (60 bytes total).
+ * The first 12 bytes store ext4_extent_header;
+ * the remainder stores an array of ext4_extent.
*/
/*
- * this is extent on-disk structure
- * it's used at the bottom of the tree
+ * This is the extent on-disk structure.
+ * It's used at the bottom of the tree.
*/
struct ext4_extent {
__le32 ee_block; /* first logical block extent covers */
__le16 ee_len; /* number of blocks covered by extent */
__le16 ee_start_hi; /* high 16 bits of physical block */
- __le32 ee_start; /* low 32 bigs of physical block */
+ __le32 ee_start_lo; /* low 32 bits of physical block */
};
/*
- * this is index on-disk structure
- * it's used at all the levels, but the bottom
+ * This is index on-disk structure.
+ * It's used at all the levels except the bottom.
*/
struct ext4_extent_idx {
__le32 ei_block; /* index covers logical blocks from 'block' */
- __le32 ei_leaf; /* pointer to the physical block of the next *
- * level. leaf or next index could bet here */
+ __le32 ei_leaf_lo; /* pointer to the physical block of the next *
+ * level. leaf or next index could be there */
__le16 ei_leaf_hi; /* high 16 bits of physical block */
__u16 ei_unused;
};
/*
- * each block (leaves and indexes), even inode-stored has header
+ * Each block (leaves and indexes), even inode-stored has header.
*/
struct ext4_extent_header {
__le16 eh_magic; /* probably will support different formats */
__le16 eh_entries; /* number of valid entries */
__le16 eh_max; /* capacity of store in entries */
- __le16 eh_depth; /* has tree real underlaying blocks? */
+ __le16 eh_depth; /* has tree real underlying blocks? */
__le32 eh_generation; /* generation of the tree */
};
#define EXT4_EXT_MAGIC cpu_to_le16(0xf30a)
/*
- * array of ext4_ext_path contains path to some extent
- * creation/lookup routines use it for traversal/splitting/etc
- * truncate uses it to simulate recursive walking
+ * Array of ext4_ext_path contains path to some extent.
+ * Creation/lookup routines use it for traversal/splitting/etc.
+ * Truncate uses it to simulate recursive walking.
*/
struct ext4_ext_path {
ext4_fsblk_t p_block;
#define EXT_MAX_BLOCK 0xffffffff
+/*
+ * EXT_INIT_MAX_LEN is the maximum number of blocks we can have in an
+ * initialized extent. This is 2^15 and not (2^16 - 1), since we use the
+ * MSB of ee_len field in the extent datastructure to signify if this
+ * particular extent is an initialized extent or an uninitialized (i.e.
+ * preallocated).
+ * EXT_UNINIT_MAX_LEN is the maximum number of blocks we can have in an
+ * uninitialized extent.
+ * If ee_len is <= 0x8000, it is an initialized extent. Otherwise, it is an
+ * uninitialized one. In other words, if MSB of ee_len is set, it is an
+ * uninitialized extent with only one special scenario when ee_len = 0x8000.
+ * In this case we can not have an uninitialized extent of zero length and
+ * thus we make it as a special case of initialized extent with 0x8000 length.
+ * This way we get better extent-to-group alignment for initialized extents.
+ * Hence, the maximum number of blocks we can have in an *initialized*
+ * extent is 2^15 (32768) and in an *uninitialized* extent is 2^15-1 (32767).
+ */
+#define EXT_INIT_MAX_LEN (1UL << 15)
+#define EXT_UNINIT_MAX_LEN (EXT_INIT_MAX_LEN - 1)
+
#define EXT_FIRST_EXTENT(__hdr__) \
((struct ext4_extent *) (((char *) (__hdr__)) + \
((struct ext4_extent_idx *) (((char *) (__hdr__)) + \
sizeof(struct ext4_extent_header)))
#define EXT_HAS_FREE_INDEX(__path__) \
- (le16_to_cpu((__path__)->p_hdr->eh_entries) \
- < le16_to_cpu((__path__)->p_hdr->eh_max))
+ (le16_to_cpu((__path__)->p_hdr->eh_entries) \
+ < le16_to_cpu((__path__)->p_hdr->eh_max))
#define EXT_LAST_EXTENT(__hdr__) \
(EXT_FIRST_EXTENT((__hdr__)) + le16_to_cpu((__hdr__)->eh_entries) - 1)
#define EXT_LAST_INDEX(__hdr__) \
EXT4_I(inode)->i_cached_extent.ec_type = EXT4_EXT_CACHE_NO;
}
+static inline void ext4_ext_mark_uninitialized(struct ext4_extent *ext)
+{
+ /* We can not have an uninitialized extent of zero length! */
+ BUG_ON((le16_to_cpu(ext->ee_len) & ~EXT_INIT_MAX_LEN) == 0);
+ ext->ee_len |= cpu_to_le16(EXT_INIT_MAX_LEN);
+}
+
+static inline int ext4_ext_is_uninitialized(struct ext4_extent *ext)
+{
+ /* Extent with ee_len of 0x8000 is treated as an initialized extent */
+ return (le16_to_cpu(ext->ee_len) > EXT_INIT_MAX_LEN);
+}
+
+static inline int ext4_ext_get_actual_len(struct ext4_extent *ext)
+{
+ return (le16_to_cpu(ext->ee_len) <= EXT_INIT_MAX_LEN ?
+ le16_to_cpu(ext->ee_len) :
+ (le16_to_cpu(ext->ee_len) - EXT_INIT_MAX_LEN));
+}
+
extern int ext4_extent_tree_init(handle_t *, struct inode *);
extern int ext4_ext_calc_credits_for_insert(struct inode *, struct ext4_ext_path *);
+extern int ext4_ext_try_to_merge(struct inode *inode,
+ struct ext4_ext_path *path,
+ struct ext4_extent *);
+extern unsigned int ext4_ext_check_overlap(struct inode *, struct ext4_extent *, struct ext4_ext_path *);
extern int ext4_ext_insert_extent(handle_t *, struct inode *, struct ext4_ext_path *, struct ext4_extent *);
extern int ext4_ext_walk_space(struct inode *, unsigned long, unsigned long, ext_prepare_callback, void *);
extern struct ext4_ext_path * ext4_ext_find_extent(struct inode *, int, struct ext4_ext_path *);
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