This patch implements persistent preallocation using ioctl. Other
options under consideration are posix_fallocate and ftruncate. The code
can be ported to other approach, if ioctl is not the favored one. The
patch takes care of marking/checking uninitialized extents.
Signed-off-by: Amit Arora <[EMAIL PROTECTED]>
---
fs/ext4/extents.c | 120 ++++++++++++++++++++++++++++++++----------------
fs/ext4/ioctl.c | 41 ++++++++++++++++
include/linux/ext4_fs.h | 21 ++++++++
3 files changed, 144 insertions(+), 38 deletions(-)
Index: linux-2.6.19/fs/ext4/extents.c
===================================================================
--- linux-2.6.19.orig/fs/ext4/extents.c 2006-12-05 16:03:40.000000000 +0530
+++ linux-2.6.19/fs/ext4/extents.c 2006-12-05 16:03:53.000000000 +0530
@@ -282,7 +282,7 @@
} else if (path->p_ext) {
ext_debug(" %d:%d:%llu ",
le32_to_cpu(path->p_ext->ee_block),
- le16_to_cpu(path->p_ext->ee_len),
+ ext4_ext_get_actual_len(path->p_ext),
ext_pblock(path->p_ext));
} else
ext_debug(" []");
@@ -305,7 +305,7 @@
for (i = 0; i < le16_to_cpu(eh->eh_entries); i++, ex++) {
ext_debug("%d:%d:%llu ", le32_to_cpu(ex->ee_block),
- le16_to_cpu(ex->ee_len), ext_pblock(ex));
+ ext4_ext_get_actual_len(ex), ext_pblock(ex));
}
ext_debug("\n");
}
@@ -425,7 +425,7 @@
ext_debug(" -> %d:%llu:%d ",
le32_to_cpu(path->p_ext->ee_block),
ext_pblock(path->p_ext),
- le16_to_cpu(path->p_ext->ee_len));
+ ext4_ext_get_actual_len(path->p_ext));
#ifdef CHECK_BINSEARCH
{
@@ -686,7 +686,7 @@
ext_debug("move %d:%llu:%d in new leaf %llu\n",
le32_to_cpu(path[depth].p_ext->ee_block),
ext_pblock(path[depth].p_ext),
- le16_to_cpu(path[depth].p_ext->ee_len),
+ ext4_ext_get_actual_len(path[depth].p_ext),
newblock);
/*memmove(ex++, path[depth].p_ext++,
sizeof(struct ext4_extent));
@@ -1097,7 +1097,23 @@
ext4_can_extents_be_merged(struct inode *inode, struct ext4_extent *ex1,
struct ext4_extent *ex2)
{
- if (le32_to_cpu(ex1->ee_block) + le16_to_cpu(ex1->ee_len) !=
+ unsigned short ext1_ee_len, ext2_ee_len;
+
+
+ /*
+ * Make sure that either both extents are uninitialized, or
+ * both are _not_.
+ */
+ if ((ext4_ext_is_uninitialized(ex1)
+ && !ext4_ext_is_uninitialized(ex2))
+ || (!ext4_ext_is_uninitialized(ex1)
+ && ext4_ext_is_uninitialized(ex2)))
+ return 0;
+
+ ext1_ee_len = ext4_ext_get_actual_len(ex1);
+ ext2_ee_len = ext4_ext_get_actual_len(ex2);
+
+ if (le32_to_cpu(ex1->ee_block) + ext1_ee_len !=
le32_to_cpu(ex2->ee_block))
return 0;
@@ -1106,14 +1122,14 @@
* as an RO_COMPAT feature, refuse to merge to extents if
* this can result in the top bit of ee_len being set.
*/
- if (le16_to_cpu(ex1->ee_len) + le16_to_cpu(ex2->ee_len) > EXT_MAX_LEN)
+ if (ext1_ee_len + ext2_ee_len > EXT_MAX_LEN)
return 0;
#ifdef AGRESSIVE_TEST
if (le16_to_cpu(ex1->ee_len) >= 4)
return 0;
#endif
- if (ext_pblock(ex1) + le16_to_cpu(ex1->ee_len) == ext_pblock(ex2))
+ if (ext_pblock(ex1) + ext1_ee_len == ext_pblock(ex2))
return 1;
return 0;
}
@@ -1132,9 +1148,9 @@
struct ext4_extent *ex, *fex;
struct ext4_extent *nearex; /* nearest extent */
struct ext4_ext_path *npath = NULL;
- int depth, len, err, next;
+ int depth, len, err, next, uninitialized = 0;
- BUG_ON(newext->ee_len == 0);
+ BUG_ON(ext4_ext_get_actual_len(newext) == 0);
depth = ext_depth(inode);
ex = path[depth].p_ext;
BUG_ON(path[depth].p_hdr == NULL);
@@ -1142,13 +1158,22 @@
/* try to insert block into found extent and return */
if (ex && ext4_can_extents_be_merged(inode, ex, newext)) {
ext_debug("append %d block to %d:%d (from %llu)\n",
- le16_to_cpu(newext->ee_len),
+ ext4_ext_get_actual_len(newext),
le32_to_cpu(ex->ee_block),
- le16_to_cpu(ex->ee_len), ext_pblock(ex));
+ ext4_ext_get_actual_len(ex), ext_pblock(ex));
if ((err = ext4_ext_get_access(handle, inode, path + depth)))
return err;
- ex->ee_len = cpu_to_le16(le16_to_cpu(ex->ee_len)
- + le16_to_cpu(newext->ee_len));
+
+ /* ext4_can_extents_be_merged should have checked that either
+ * both extents are uninitialized, or both aren't. Thus we
+ * need to check any of them here.
+ */
+ if (ext4_ext_is_uninitialized(ex))
+ uninitialized = 1;
+ ex->ee_len = cpu_to_le16(ext4_ext_get_actual_len(ex)
+ + ext4_ext_get_actual_len(newext));
+ if(uninitialized)
+ ext4_mark_uninitialized_ext(ex);
eh = path[depth].p_hdr;
nearex = ex;
goto merge;
@@ -1203,7 +1228,7 @@
ext_debug("first extent in the leaf: %d:%llu:%d\n",
le32_to_cpu(newext->ee_block),
ext_pblock(newext),
- le16_to_cpu(newext->ee_len));
+ ext4_mark_uninitialized_ext(newext));
path[depth].p_ext = EXT_FIRST_EXTENT(eh);
} else if (le32_to_cpu(newext->ee_block)
> le32_to_cpu(nearex->ee_block)) {
@@ -1216,7 +1241,7 @@
"move %d from 0x%p to 0x%p\n",
le32_to_cpu(newext->ee_block),
ext_pblock(newext),
- le16_to_cpu(newext->ee_len),
+ ext4_mark_uninitialized_ext(newext),
nearex, len, nearex + 1, nearex + 2);
memmove(nearex + 2, nearex + 1, len);
}
@@ -1229,7 +1254,7 @@
"move %d from 0x%p to 0x%p\n",
le32_to_cpu(newext->ee_block),
ext_pblock(newext),
- le16_to_cpu(newext->ee_len),
+ ext4_ext_get_actual_len(newext),
nearex, len, nearex + 1, nearex + 2);
memmove(nearex + 1, nearex, len);
path[depth].p_ext = nearex;
@@ -1248,8 +1273,13 @@
if (!ext4_can_extents_be_merged(inode, nearex, nearex + 1))
break;
/* merge with next extent! */
- nearex->ee_len = cpu_to_le16(le16_to_cpu(nearex->ee_len)
- + le16_to_cpu(nearex[1].ee_len));
+ if (ext4_ext_is_uninitialized(nearex))
+ uninitialized = 1;
+ nearex->ee_len = cpu_to_le16(ext4_ext_get_actual_len(nearex)
+ + ext4_ext_get_actual_len(nearex +
1));
+ if(uninitialized)
+ ext4_mark_uninitialized_ext(nearex);
+
if (nearex + 1 < EXT_LAST_EXTENT(eh)) {
len = (EXT_LAST_EXTENT(eh) - nearex - 1)
* sizeof(struct ext4_extent);
@@ -1319,8 +1349,8 @@
end = le32_to_cpu(ex->ee_block);
if (block + num < end)
end = block + num;
- } else if (block >=
- le32_to_cpu(ex->ee_block) +
le16_to_cpu(ex->ee_len)) {
+ } else if (block >= le32_to_cpu(ex->ee_block)
+ + ext4_ext_get_actual_len(ex)) {
/* need to allocate space after found extent */
start = block;
end = block + num;
@@ -1332,7 +1362,8 @@
* by found extent
*/
start = block;
- end = le32_to_cpu(ex->ee_block) +
le16_to_cpu(ex->ee_len);
+ end = le32_to_cpu(ex->ee_block)
+ + ext4_ext_get_actual_len(ex);
if (block + num < end)
end = block + num;
exists = 1;
@@ -1348,7 +1379,7 @@
cbex.ec_type = EXT4_EXT_CACHE_GAP;
} else {
cbex.ec_block = le32_to_cpu(ex->ee_block);
- cbex.ec_len = le16_to_cpu(ex->ee_len);
+ cbex.ec_len = ext4_ext_get_actual_len(ex);
cbex.ec_start = ext_pblock(ex);
cbex.ec_type = EXT4_EXT_CACHE_EXTENT;
}
@@ -1556,12 +1587,12 @@
unsigned long from, unsigned long to)
{
struct buffer_head *bh;
+ unsigned short ee_len = ext4_ext_get_actual_len(ex);
int i;
#ifdef EXTENTS_STATS
{
struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
- unsigned short ee_len = le16_to_cpu(ex->ee_len);
spin_lock(&sbi->s_ext_stats_lock);
sbi->s_ext_blocks += ee_len;
sbi->s_ext_extents++;
@@ -1575,12 +1606,12 @@
}
#endif
if (from >= le32_to_cpu(ex->ee_block)
- && to == le32_to_cpu(ex->ee_block) + le16_to_cpu(ex->ee_len) - 1) {
+ && to == le32_to_cpu(ex->ee_block) + ee_len - 1) {
/* tail removal */
unsigned long num;
ext4_fsblk_t start;
- num = le32_to_cpu(ex->ee_block) + le16_to_cpu(ex->ee_len) -
from;
- start = ext_pblock(ex) + le16_to_cpu(ex->ee_len) - num;
+ num = le32_to_cpu(ex->ee_block) + ee_len - from;
+ start = ext_pblock(ex) + ee_len - num;
ext_debug("free last %lu blocks starting %llu\n", num, start);
for (i = 0; i < num; i++) {
bh = sb_find_get_block(inode->i_sb, start + i);
@@ -1588,12 +1619,12 @@
}
ext4_free_blocks(handle, inode, start, num);
} else if (from == le32_to_cpu(ex->ee_block)
- && to <= le32_to_cpu(ex->ee_block) + le16_to_cpu(ex->ee_len)
- 1) {
+ && to <= le32_to_cpu(ex->ee_block) + ee_len - 1) {
printk("strange request: removal %lu-%lu from %u:%u\n",
- from, to, le32_to_cpu(ex->ee_block),
le16_to_cpu(ex->ee_len));
+ from, to, le32_to_cpu(ex->ee_block), ee_len);
} else {
printk("strange request: removal(2) %lu-%lu from %u:%u\n",
- from, to, le32_to_cpu(ex->ee_block),
le16_to_cpu(ex->ee_len));
+ from, to, le32_to_cpu(ex->ee_block), ee_len);
}
return 0;
}
@@ -1607,7 +1638,7 @@
struct ext4_extent_header *eh;
unsigned a, b, block, num;
unsigned long ex_ee_block;
- unsigned short ex_ee_len;
+ unsigned short ex_ee_len, uninitialized = 0;
struct ext4_extent *ex;
ext_debug("truncate since %lu in leaf\n", start);
@@ -1622,7 +1653,9 @@
ex = EXT_LAST_EXTENT(eh);
ex_ee_block = le32_to_cpu(ex->ee_block);
- ex_ee_len = le16_to_cpu(ex->ee_len);
+ if(ext4_ext_is_uninitialized(ex))
+ uninitialized = 1;
+ ex_ee_len = ext4_ext_get_actual_len(ex);
while (ex >= EXT_FIRST_EXTENT(eh) &&
ex_ee_block + ex_ee_len > start) {
@@ -1690,6 +1723,8 @@
ex->ee_block = cpu_to_le32(block);
ex->ee_len = cpu_to_le16(num);
+ if(uninitialized)
+ ext4_mark_uninitialized_ext(ex);
err = ext4_ext_dirty(handle, inode, path + depth);
if (err)
@@ -1699,7 +1734,7 @@
ext_pblock(ex));
ex--;
ex_ee_block = le32_to_cpu(ex->ee_block);
- ex_ee_len = le16_to_cpu(ex->ee_len);
+ ex_ee_len = ext4_ext_get_actual_len(ex);
}
if (correct_index && eh->eh_entries)
@@ -1974,7 +2009,7 @@
if ((ex = path[depth].p_ext)) {
unsigned long ee_block = le32_to_cpu(ex->ee_block);
ext4_fsblk_t ee_start = ext_pblock(ex);
- unsigned short ee_len = le16_to_cpu(ex->ee_len);
+ unsigned short ee_len;
/*
* Allow future support for preallocated extents to be added
@@ -1982,8 +2017,11 @@
* Uninitialized extents are treated as holes, except that
* we avoid (fail) allocating new blocks during a write.
*/
- if (ee_len > EXT_MAX_LEN)
+ if (le16_to_cpu(ex->ee_len) > EXT_MAX_LEN
+ && create != EXT4_CREATE_UNINITIALIZED_EXT)
goto out2;
+
+ ee_len = ext4_ext_get_actual_len(ex);
/* if found extent covers block, simply return it */
if (iblock >= ee_block && iblock < ee_block + ee_len) {
newblock = iblock - ee_block + ee_start;
@@ -1991,8 +2029,10 @@
allocated = ee_len - (iblock - ee_block);
ext_debug("%d fit into %lu:%d -> %llu\n", (int) iblock,
ee_block, ee_len, newblock);
- ext4_ext_put_in_cache(inode, ee_block, ee_len,
- ee_start,
EXT4_EXT_CACHE_EXTENT);
+ /* Do not put uninitialized extent in the cache */
+ if(!ext4_ext_is_uninitialized(ex))
+ ext4_ext_put_in_cache(inode, ee_block, ee_len,
+ ee_start, EXT4_EXT_CACHE_EXTENT);
goto out;
}
}
@@ -2027,6 +2067,8 @@
newex.ee_block = cpu_to_le32(iblock);
ext4_ext_store_pblock(&newex, newblock);
newex.ee_len = cpu_to_le16(allocated);
+ if(create == EXT4_CREATE_UNINITIALIZED_EXT) /* Mark uninitialized */
+ ext4_mark_uninitialized_ext(&newex);
err = ext4_ext_insert_extent(handle, inode, path, &newex);
if (err)
goto out2;
@@ -2038,8 +2080,10 @@
newblock = ext_pblock(&newex);
__set_bit(BH_New, &bh_result->b_state);
- ext4_ext_put_in_cache(inode, iblock, allocated, newblock,
- EXT4_EXT_CACHE_EXTENT);
+ /* Cache only when it is _not_ an uninitialized extent */
+ if(create!=EXT4_CREATE_UNINITIALIZED_EXT)
+ ext4_ext_put_in_cache(inode, iblock, allocated, newblock,
+ EXT4_EXT_CACHE_EXTENT);
out:
if (allocated > max_blocks)
allocated = max_blocks;
Index: linux-2.6.19/fs/ext4/ioctl.c
===================================================================
--- linux-2.6.19.orig/fs/ext4/ioctl.c 2006-12-05 16:03:40.000000000 +0530
+++ linux-2.6.19/fs/ext4/ioctl.c 2006-12-05 16:03:43.000000000 +0530
@@ -248,6 +248,47 @@
return err;
}
+ case EXT4_IOC_PREALLOCATE: {
+ struct ext4_falloc_input input;
+ handle_t *handle;
+ ext4_fsblk_t block, max_blocks;
+ int ret = 0;
+ struct buffer_head map_bh;
+ unsigned int blkbits = inode->i_blkbits;
+
+ if (IS_RDONLY(inode))
+ return -EROFS;
+
+ if (copy_from_user(&input,
+ (struct ext4_falloc_input __user *) arg, sizeof(input)))
+ return -EFAULT;
+
+ if (input.len == 0)
+ return -EINVAL;
+
+ if (!(EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL))
+ return -ENOTTY;
+
+ block = EXT4_BLOCK_ALIGN(input.offset, blkbits) >> blkbits;
+ max_blocks = EXT4_BLOCK_ALIGN(input.len, blkbits) >> blkbits;
+ handle=ext4_journal_start(inode,
+ EXT4_DATA_TRANS_BLOCKS(inode->i_sb)+max_blocks);
+ if (IS_ERR(handle))
+ return PTR_ERR(handle);
+ while(ret>=0 && ret<max_blocks)
+ {
+ block = block + ret;
+ max_blocks = max_blocks - ret;
+ ret = ext4_ext_get_blocks(handle, inode, block,
+ max_blocks, &map_bh,
+ EXT4_CREATE_UNINITIALIZED_EXT, 1);
+ }
+ ext4_mark_inode_dirty(handle, inode);
+ ext4_journal_stop(handle);
+
+ return ret>0?0:ret;
+ }
+
default:
return -ENOTTY;
}
Index: linux-2.6.19/include/linux/ext4_fs.h
===================================================================
--- linux-2.6.19.orig/include/linux/ext4_fs.h 2006-12-05 16:03:40.000000000
+0530
+++ linux-2.6.19/include/linux/ext4_fs.h 2006-12-05 16:03:53.000000000
+0530
@@ -102,6 +102,8 @@
EXT4_GOOD_OLD_FIRST_INO : \
(s)->s_first_ino)
#endif
+#define EXT4_BLOCK_ALIGN(size, blkbits) (((size)+(1 << blkbits)-1) & \
+ (~((1 << blkbits)-1)))
/*
* Macro-instructions used to manage fragments
@@ -118,6 +120,19 @@
#endif
/*
+ * Macro-instructions used to handle (mark/unmark/check/create) unitialized
+ * extents. Applications can issue an IOCTL for preallocation, which results
+ * in assigning unitialized extents to the file
+ */
+#define EXT4_CREATE_UNINITIALIZED_EXT 2
+#define ext4_mark_uninitialized_ext(ext) ((ext)->ee_len |= \
+ cpu_to_le16(0x8000))
+#define ext4_ext_is_uninitialized(ext) ((le16_to_cpu((ext)->ee_len))& \
+ 0x8000)
+#define ext4_ext_get_actual_len(ext) ((le16_to_cpu((ext)->ee_len))& \
+ 0x7FFF)
+
+/*
* Structure of a blocks group descriptor
*/
struct ext4_group_desc
@@ -225,6 +240,11 @@
__u32 free_blocks_count;
};
+/* The struct ext4_falloc_input in kernel, for EXT4_IOC_PREALLOCATE */
+struct ext4_falloc_input {
+ __u64 offset;
+ __u64 len;
+};
/*
* ioctl commands
@@ -242,6 +262,7 @@
#endif
#define EXT4_IOC_GETRSVSZ _IOR('f', 5, long)
#define EXT4_IOC_SETRSVSZ _IOW('f', 6, long)
+#define EXT4_IOC_PREALLOCATE _IOW('f', 9, struct ext4_falloc_input)
/*
* ioctl commands in 32 bit emulation
-
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