[Devel] [PATCH vz7] ext4: replace ext4_kvmalloc() with kvmalloc()
Oleg Babin
obabin at virtuozzo.com
Fri May 11 17:08:55 MSK 2018
ext4_kvmalloc() is used to allocate the table of group descritors
blocks. It is called in GFP_NOFS context which is not vmalloc()
compatible so it cannot be directly replaced with kvmalloc().
In order to use kvmalloc() with GFP_KERNEL flag the memory allocation
is moved from add_new_gdb() / add_new_gdb_meta_bg() functions to the
beginning of the resize process before any journaling is started and
any FS locks are taken.
After this we do not need ext4_kvmalloc/ext4_kvfree functions any more
so remove them.
https://jira.sw.ru/browse/PSBM-83044
Signed-off-by: Oleg Babin <obabin at virtuozzo.com>
---
fs/ext4/ext4.h | 3 --
fs/ext4/mballoc.c | 6 +--
fs/ext4/resize.c | 110 +++++++++++++++++++++++++++++++++++-------------------
fs/ext4/super.c | 39 +++----------------
4 files changed, 79 insertions(+), 79 deletions(-)
diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index 00903ac..ceb69e8 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -2304,9 +2304,6 @@ extern int ext4_resize_fs(struct super_block *sb, ext4_fsblk_t n_blocks_count);
/* super.c */
extern int ext4_calculate_overhead(struct super_block *sb);
extern void ext4_superblock_csum_set(struct super_block *sb);
-extern void *ext4_kvmalloc(size_t size, gfp_t flags);
-extern void *ext4_kvzalloc(size_t size, gfp_t flags);
-extern void ext4_kvfree(void *ptr);
extern int ext4_alloc_flex_bg_array(struct super_block *sb,
ext4_group_t ngroup);
extern const char *ext4_decode_error(struct super_block *sb, int errno,
diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
index b3ddecb..d9778e4 100644
--- a/fs/ext4/mballoc.c
+++ b/fs/ext4/mballoc.c
@@ -2358,7 +2358,7 @@ int ext4_mb_alloc_groupinfo(struct super_block *sb, ext4_group_t ngroups)
if (sbi->s_group_info) {
memcpy(new_groupinfo, sbi->s_group_info,
sbi->s_group_info_size * sizeof(*sbi->s_group_info));
- ext4_kvfree(sbi->s_group_info);
+ kvfree(sbi->s_group_info);
}
sbi->s_group_info = new_groupinfo;
sbi->s_group_info_size = size / sizeof(*sbi->s_group_info);
@@ -2495,7 +2495,7 @@ err_freebuddy:
kfree(sbi->s_group_info[i]);
iput(sbi->s_buddy_cache);
err_freesgi:
- ext4_kvfree(sbi->s_group_info);
+ kvfree(sbi->s_group_info);
return -ENOMEM;
}
@@ -2710,7 +2710,7 @@ int ext4_mb_release(struct super_block *sb)
EXT4_DESC_PER_BLOCK_BITS(sb);
for (i = 0; i < num_meta_group_infos; i++)
kfree(sbi->s_group_info[i]);
- ext4_kvfree(sbi->s_group_info);
+ kvfree(sbi->s_group_info);
}
kfree(sbi->s_mb_offsets);
kfree(sbi->s_mb_maxs);
diff --git a/fs/ext4/resize.c b/fs/ext4/resize.c
index 218fd6f..90a92ad 100644
--- a/fs/ext4/resize.c
+++ b/fs/ext4/resize.c
@@ -79,6 +79,11 @@ static ext4_grpblk_t ext4_group_overhead_blocks(struct super_block *sb,
return overhead;
}
+static unsigned long num_desc_blocks(struct super_block *sb, ext4_group_t groups)
+{
+ return (groups + EXT4_DESC_PER_BLOCK(sb) - 1) / EXT4_DESC_PER_BLOCK(sb);
+}
+
#define outside(b, first, last) ((b) < (first) || (b) >= (last))
#define inside(b, first, last) ((b) >= (first) && (b) < (last))
@@ -738,6 +743,49 @@ static int verify_reserved_gdb(struct super_block *sb,
}
/*
+ * Allocate the top-level s_group_desc array for the specified number
+ * of groups. As the memory is allocated before the journaling is started
+ * we can safely use kvmalloc() with GFP_KERNEL flag here.
+ */
+static int ext4_alloc_group_desc_bh_array(struct super_block *sb,
+ ext4_group_t n_groups_count)
+{
+ struct ext4_sb_info *sbi = EXT4_SB(sb);
+ unsigned long o_gdb_count = sbi->s_gdb_count;
+ unsigned long n_gdb_count = num_desc_blocks(sb, n_groups_count);
+ struct buffer_head **o_group_desc, **n_group_desc;
+
+ if (n_gdb_count <= o_gdb_count)
+ return 0;
+
+ o_group_desc = sbi->s_group_desc;
+ n_group_desc = kvmalloc(n_gdb_count * sizeof(struct buffer_head *),
+ GFP_KERNEL);
+ if (!n_group_desc) {
+ ext4_warning(sb, "not enough memory for %lu groups", n_gdb_count);
+ return -ENOMEM;
+ }
+
+ memcpy(n_group_desc, o_group_desc,
+ o_gdb_count * sizeof(struct buffer_head *));
+
+ memset(n_group_desc + o_gdb_count * sizeof(struct buffer_head *),
+ 0, (n_gdb_count - o_gdb_count) * sizeof(struct buffer_head *));
+
+ sbi->s_group_desc = n_group_desc;
+
+ /*
+ * Do not update sbi->s_gdb_count here as it can be used later
+ * in reserve_backup_gdb(). The field will be upated later in
+ * add_new_gdb() / add_new_gdb_meta_bg().
+ */
+
+ kvfree(o_group_desc);
+
+ return 0;
+}
+
+/*
* Called when we need to bring a reserved group descriptor table block into
* use from the resize inode. The primary copy of the new GDT block currently
* is an indirect block (under the double indirect block in the resize inode).
@@ -757,7 +805,6 @@ static int add_new_gdb(handle_t *handle, struct inode *inode,
struct ext4_super_block *es = EXT4_SB(sb)->s_es;
unsigned long gdb_num = group / EXT4_DESC_PER_BLOCK(sb);
ext4_fsblk_t gdblock = EXT4_SB(sb)->s_sbh->b_blocknr + 1 + gdb_num;
- struct buffer_head **o_group_desc, **n_group_desc;
struct buffer_head *dind;
struct buffer_head *gdb_bh;
int gdbackups;
@@ -815,16 +862,6 @@ static int add_new_gdb(handle_t *handle, struct inode *inode,
if (unlikely(err))
goto exit_dind;
- n_group_desc = ext4_kvmalloc((gdb_num + 1) *
- sizeof(struct buffer_head *),
- GFP_NOFS);
- if (!n_group_desc) {
- err = -ENOMEM;
- ext4_warning(sb, "not enough memory for %lu groups",
- gdb_num + 1);
- goto exit_inode;
- }
-
/*
* Finally, we have all of the possible failures behind us...
*
@@ -850,13 +887,14 @@ static int add_new_gdb(handle_t *handle, struct inode *inode,
}
brelse(dind);
- o_group_desc = EXT4_SB(sb)->s_group_desc;
- memcpy(n_group_desc, o_group_desc,
- EXT4_SB(sb)->s_gdb_count * sizeof(struct buffer_head *));
- n_group_desc[gdb_num] = gdb_bh;
- EXT4_SB(sb)->s_group_desc = n_group_desc;
+ /*
+ * The s_group_desc array was reallocated at the beginning of the
+ * resize process but the s_gdb_count field had not been updated
+ * then because we use its old value in the reserve_backup_gdb().
+ */
+ BUG_ON(gdb_num != EXT4_SB(sb)->s_gdb_count);
+ EXT4_SB(sb)->s_group_desc[gdb_num] = gdb_bh;
EXT4_SB(sb)->s_gdb_count++;
- ext4_kvfree(o_group_desc);
le16_add_cpu(&es->s_reserved_gdt_blocks, -1);
err = ext4_handle_dirty_super(handle, sb);
@@ -866,7 +904,6 @@ static int add_new_gdb(handle_t *handle, struct inode *inode,
return err;
exit_inode:
- ext4_kvfree(n_group_desc);
brelse(iloc.bh);
exit_dind:
brelse(dind);
@@ -884,7 +921,6 @@ static int add_new_gdb_meta_bg(struct super_block *sb,
handle_t *handle, ext4_group_t group) {
ext4_fsblk_t gdblock;
struct buffer_head *gdb_bh;
- struct buffer_head **o_group_desc, **n_group_desc;
unsigned long gdb_num = group / EXT4_DESC_PER_BLOCK(sb);
int err;
@@ -893,23 +929,16 @@ static int add_new_gdb_meta_bg(struct super_block *sb,
gdb_bh = sb_bread(sb, gdblock);
if (!gdb_bh)
return -EIO;
- n_group_desc = ext4_kvmalloc((gdb_num + 1) *
- sizeof(struct buffer_head *),
- GFP_NOFS);
- if (!n_group_desc) {
- err = -ENOMEM;
- ext4_warning(sb, "not enough memory for %lu groups",
- gdb_num + 1);
- return err;
- }
- o_group_desc = EXT4_SB(sb)->s_group_desc;
- memcpy(n_group_desc, o_group_desc,
- EXT4_SB(sb)->s_gdb_count * sizeof(struct buffer_head *));
- n_group_desc[gdb_num] = gdb_bh;
- EXT4_SB(sb)->s_group_desc = n_group_desc;
+ /*
+ * The s_group_desc array was reallocated at the beginning of the
+ * resize process but the s_gdb_count field had not been updated
+ * then because we use its old value in the reserve_backup_gdb().
+ */
+ BUG_ON(gdb_num != EXT4_SB(sb)->s_gdb_count);
+ EXT4_SB(sb)->s_group_desc[gdb_num] = gdb_bh;
EXT4_SB(sb)->s_gdb_count++;
- ext4_kvfree(o_group_desc);
+
BUFFER_TRACE(gdb_bh, "get_write_access");
err = ext4_journal_get_write_access(handle, gdb_bh);
if (unlikely(err))
@@ -1623,6 +1652,10 @@ int ext4_group_add(struct super_block *sb, struct ext4_new_group_data *input)
if (err)
goto out;
+ err = ext4_alloc_group_desc_bh_array(sb, input->group + 1);
+ if (err)
+ goto out;
+
err = ext4_alloc_flex_bg_array(sb, input->group + 1);
if (err)
goto out;
@@ -1772,11 +1805,6 @@ int ext4_group_extend(struct super_block *sb, struct ext4_super_block *es,
} /* ext4_group_extend */
-static int num_desc_blocks(struct super_block *sb, ext4_group_t groups)
-{
- return (groups + EXT4_DESC_PER_BLOCK(sb) - 1) / EXT4_DESC_PER_BLOCK(sb);
-}
-
/*
* Release the resize inode and drop the resize_inode feature if there
* are no more reserved gdt blocks, and then convert the file system
@@ -1973,6 +2001,10 @@ retry:
if (ext4_blocks_count(es) == n_blocks_count)
goto out;
+ err = ext4_alloc_group_desc_bh_array(sb, n_group + 1);
+ if (err)
+ goto out;
+
err = ext4_alloc_flex_bg_array(sb, n_group + 1);
if (err)
return err;
diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index f644bf0..3fbcf86 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -157,35 +157,6 @@ void ext4_superblock_csum_set(struct super_block *sb)
es->s_checksum = ext4_superblock_csum(sb, es);
}
-void *ext4_kvmalloc(size_t size, gfp_t flags)
-{
- void *ret;
-
- ret = kmalloc(size, flags);
- if (!ret)
- ret = __vmalloc(size, flags, PAGE_KERNEL);
- return ret;
-}
-
-void *ext4_kvzalloc(size_t size, gfp_t flags)
-{
- void *ret;
-
- ret = kzalloc(size, flags);
- if (!ret)
- ret = __vmalloc(size, flags | __GFP_ZERO, PAGE_KERNEL);
- return ret;
-}
-
-void ext4_kvfree(void *ptr)
-{
- if (is_vmalloc_addr(ptr))
- vfree(ptr);
- else
- kfree(ptr);
-
-}
-
ext4_fsblk_t ext4_block_bitmap(struct super_block *sb,
struct ext4_group_desc *bg)
{
@@ -947,8 +918,8 @@ static void ext4_put_super(struct super_block *sb)
for (i = 0; i < sbi->s_gdb_count; i++)
brelse(sbi->s_group_desc[i]);
- ext4_kvfree(sbi->s_group_desc);
- ext4_kvfree(sbi->s_flex_groups);
+ kvfree(sbi->s_group_desc);
+ kvfree(sbi->s_flex_groups);
percpu_counter_destroy(&sbi->s_freeclusters_counter);
percpu_counter_destroy(&sbi->s_freeinodes_counter);
percpu_counter_destroy(&sbi->s_dirs_counter);
@@ -2191,7 +2162,7 @@ int ext4_alloc_flex_bg_array(struct super_block *sb, ext4_group_t ngroup)
memcpy(new_groups, sbi->s_flex_groups,
(sbi->s_flex_groups_allocated *
sizeof(struct flex_groups)));
- ext4_kvfree(sbi->s_flex_groups);
+ kvfree(sbi->s_flex_groups);
}
sbi->s_flex_groups = new_groups;
sbi->s_flex_groups_allocated = size / sizeof(struct flex_groups);
@@ -4674,7 +4645,7 @@ failed_mount7:
failed_mount6:
ext4_mb_release(sb);
if (sbi->s_flex_groups)
- ext4_kvfree(sbi->s_flex_groups);
+ kvfree(sbi->s_flex_groups);
percpu_counter_destroy(&sbi->s_freeclusters_counter);
percpu_counter_destroy(&sbi->s_freeinodes_counter);
percpu_counter_destroy(&sbi->s_dirs_counter);
@@ -4706,7 +4677,7 @@ failed_mount3:
failed_mount2:
for (i = 0; i < db_count; i++)
brelse(sbi->s_group_desc[i]);
- ext4_kvfree(sbi->s_group_desc);
+ kvfree(sbi->s_group_desc);
failed_mount:
if (sbi->s_chksum_driver)
crypto_free_shash(sbi->s_chksum_driver);
--
1.8.3.1
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