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-rw-r--r--Documentation/filesystems/ext4.txt11
-rw-r--r--fs/ext4/balloc.c18
-rw-r--r--fs/ext4/ext4.h13
-rw-r--r--fs/ext4/extents.c27
-rw-r--r--fs/ext4/inode.c11
-rw-r--r--fs/ext4/super.c84
6 files changed, 141 insertions, 23 deletions
diff --git a/Documentation/filesystems/ext4.txt b/Documentation/filesystems/ext4.txt
index 5dd957d..f7cbf57 100644
--- a/Documentation/filesystems/ext4.txt
+++ b/Documentation/filesystems/ext4.txt
@@ -494,6 +494,17 @@ Files in /sys/fs/ext4/<devname>
session_write_kbytes This file is read-only and shows the number of
kilobytes of data that have been written to this
filesystem since it was mounted.
+
+ reserved_clusters This is RW file and contains number of reserved
+ clusters in the file system which will be used
+ in the specific situations to avoid costly
+ zeroout, unexpected ENOSPC, or possible data
+ loss. The default is 2% or 4096 clusters,
+ whichever is smaller and this can be changed
+ however it can never exceed number of clusters
+ in the file system. If there is not enough space
+ for the reserved space when mounting the file
+ mount will _not_ fail.
..............................................................................
Ioctls
diff --git a/fs/ext4/balloc.c b/fs/ext4/balloc.c
index 9e8d8ff..8dcaea6 100644
--- a/fs/ext4/balloc.c
+++ b/fs/ext4/balloc.c
@@ -499,20 +499,22 @@ ext4_read_block_bitmap(struct super_block *sb, ext4_group_t block_group)
static int ext4_has_free_clusters(struct ext4_sb_info *sbi,
s64 nclusters, unsigned int flags)
{
- s64 free_clusters, dirty_clusters, root_clusters;
+ s64 free_clusters, dirty_clusters, rsv, resv_clusters;
struct percpu_counter *fcc = &sbi->s_freeclusters_counter;
struct percpu_counter *dcc = &sbi->s_dirtyclusters_counter;
free_clusters = percpu_counter_read_positive(fcc);
dirty_clusters = percpu_counter_read_positive(dcc);
+ resv_clusters = atomic64_read(&sbi->s_resv_clusters);
/*
* r_blocks_count should always be multiple of the cluster ratio so
* we are safe to do a plane bit shift only.
*/
- root_clusters = ext4_r_blocks_count(sbi->s_es) >> sbi->s_cluster_bits;
+ rsv = (ext4_r_blocks_count(sbi->s_es) >> sbi->s_cluster_bits) +
+ resv_clusters;
- if (free_clusters - (nclusters + root_clusters + dirty_clusters) <
+ if (free_clusters - (nclusters + rsv + dirty_clusters) <
EXT4_FREECLUSTERS_WATERMARK) {
free_clusters = percpu_counter_sum_positive(fcc);
dirty_clusters = percpu_counter_sum_positive(dcc);
@@ -520,15 +522,21 @@ static int ext4_has_free_clusters(struct ext4_sb_info *sbi,
/* Check whether we have space after accounting for current
* dirty clusters & root reserved clusters.
*/
- if (free_clusters >= ((root_clusters + nclusters) + dirty_clusters))
+ if (free_clusters >= (rsv + nclusters + dirty_clusters))
return 1;
/* Hm, nope. Are (enough) root reserved clusters available? */
if (uid_eq(sbi->s_resuid, current_fsuid()) ||
(!gid_eq(sbi->s_resgid, GLOBAL_ROOT_GID) && in_group_p(sbi->s_resgid)) ||
capable(CAP_SYS_RESOURCE) ||
- (flags & EXT4_MB_USE_ROOT_BLOCKS)) {
+ (flags & EXT4_MB_USE_ROOT_BLOCKS)) {
+ if (free_clusters >= (nclusters + dirty_clusters +
+ resv_clusters))
+ return 1;
+ }
+ /* No free blocks. Let's see if we can dip into reserved pool */
+ if (flags & EXT4_MB_USE_RESERVED) {
if (free_clusters >= (nclusters + dirty_clusters))
return 1;
}
diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index d918715..12b5604 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -121,6 +121,8 @@ typedef unsigned int ext4_group_t;
#define EXT4_MB_STREAM_ALLOC 0x0800
/* Use reserved root blocks if needed */
#define EXT4_MB_USE_ROOT_BLOCKS 0x1000
+/* Use blocks from reserved pool */
+#define EXT4_MB_USE_RESERVED 0x2000
struct ext4_allocation_request {
/* target inode for block we're allocating */
@@ -557,9 +559,8 @@ enum {
#define EXT4_GET_BLOCKS_UNINIT_EXT 0x0002
#define EXT4_GET_BLOCKS_CREATE_UNINIT_EXT (EXT4_GET_BLOCKS_UNINIT_EXT|\
EXT4_GET_BLOCKS_CREATE)
- /* Caller is from the delayed allocation writeout path,
- so set the magic i_delalloc_reserve_flag after taking the
- inode allocation semaphore for */
+ /* Caller is from the delayed allocation writeout path
+ * finally doing the actual allocation of delayed blocks */
#define EXT4_GET_BLOCKS_DELALLOC_RESERVE 0x0004
/* caller is from the direct IO path, request to creation of an
unitialized extents if not allocated, split the uninitialized
@@ -571,8 +572,9 @@ enum {
/* Convert extent to initialized after IO complete */
#define EXT4_GET_BLOCKS_IO_CONVERT_EXT (EXT4_GET_BLOCKS_CONVERT|\
EXT4_GET_BLOCKS_CREATE_UNINIT_EXT)
- /* Punch out blocks of an extent */
-#define EXT4_GET_BLOCKS_PUNCH_OUT_EXT 0x0020
+ /* Eventual metadata allocation (due to growing extent tree)
+ * should not fail, so try to use reserved blocks for that.*/
+#define EXT4_GET_BLOCKS_METADATA_NOFAIL 0x0020
/* Don't normalize allocation size (used for fallocate) */
#define EXT4_GET_BLOCKS_NO_NORMALIZE 0x0040
/* Request will not result in inode size update (user for fallocate) */
@@ -1188,6 +1190,7 @@ struct ext4_sb_info {
unsigned int s_mount_flags;
unsigned int s_def_mount_opt;
ext4_fsblk_t s_sb_block;
+ atomic64_t s_resv_clusters;
kuid_t s_resuid;
kgid_t s_resgid;
unsigned short s_mount_state;
diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
index ea607f9..8b158ae 100644
--- a/fs/ext4/extents.c
+++ b/fs/ext4/extents.c
@@ -1942,8 +1942,8 @@ prepend:
* There is no free space in the found leaf.
* We're gonna add a new leaf in the tree.
*/
- if (flag & EXT4_GET_BLOCKS_PUNCH_OUT_EXT)
- flags = EXT4_MB_USE_ROOT_BLOCKS;
+ if (flag & EXT4_GET_BLOCKS_METADATA_NOFAIL)
+ flags = EXT4_MB_USE_RESERVED;
err = ext4_ext_create_new_leaf(handle, inode, flags, path, newext);
if (err)
goto cleanup;
@@ -2729,12 +2729,14 @@ again:
/*
* Split the extent in two so that 'end' is the last
- * block in the first new extent
+ * block in the first new extent. Also we should not
+ * fail removing space due to ENOSPC so try to use
+ * reserved block if that happens.
*/
err = ext4_split_extent_at(handle, inode, path,
- end + 1, split_flag,
- EXT4_GET_BLOCKS_PRE_IO |
- EXT4_GET_BLOCKS_PUNCH_OUT_EXT);
+ end + 1, split_flag,
+ EXT4_GET_BLOCKS_PRE_IO |
+ EXT4_GET_BLOCKS_METADATA_NOFAIL);
if (err < 0)
goto out;
@@ -3209,7 +3211,8 @@ out:
static int ext4_ext_convert_to_initialized(handle_t *handle,
struct inode *inode,
struct ext4_map_blocks *map,
- struct ext4_ext_path *path)
+ struct ext4_ext_path *path,
+ int flags)
{
struct ext4_sb_info *sbi;
struct ext4_extent_header *eh;
@@ -3435,7 +3438,7 @@ static int ext4_ext_convert_to_initialized(handle_t *handle,
}
allocated = ext4_split_extent(handle, inode, path,
- &split_map, split_flag, 0);
+ &split_map, split_flag, flags);
if (allocated < 0)
err = allocated;
@@ -3755,6 +3758,12 @@ ext4_ext_handle_uninitialized_extents(handle_t *handle, struct inode *inode,
flags, allocated);
ext4_ext_show_leaf(inode, path);
+ /*
+ * When writing into uninitialized space, we should not fail to
+ * allocate metadata blocks for the new extent block if needed.
+ */
+ flags |= EXT4_GET_BLOCKS_METADATA_NOFAIL;
+
trace_ext4_ext_handle_uninitialized_extents(inode, map, flags,
allocated, newblock);
@@ -3818,7 +3827,7 @@ ext4_ext_handle_uninitialized_extents(handle_t *handle, struct inode *inode,
}
/* buffered write, writepage time, convert*/
- ret = ext4_ext_convert_to_initialized(handle, inode, map, path);
+ ret = ext4_ext_convert_to_initialized(handle, inode, map, path, flags);
if (ret >= 0)
ext4_update_inode_fsync_trans(handle, inode, 1);
out:
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index f9b0b47..629d67b 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -1688,12 +1688,21 @@ static void mpage_da_map_and_submit(struct mpage_da_data *mpd)
*/
map.m_lblk = next;
map.m_len = max_blocks;
- get_blocks_flags = EXT4_GET_BLOCKS_CREATE;
+ /*
+ * We're in delalloc path and it is possible that we're going to
+ * need more metadata blocks than previously reserved. However
+ * we must not fail because we're in writeback and there is
+ * nothing we can do about it so it might result in data loss.
+ * So use reserved blocks to allocate metadata if possible.
+ */
+ get_blocks_flags = EXT4_GET_BLOCKS_CREATE |
+ EXT4_GET_BLOCKS_METADATA_NOFAIL;
if (ext4_should_dioread_nolock(mpd->inode))
get_blocks_flags |= EXT4_GET_BLOCKS_IO_CREATE_EXT;
if (mpd->b_state & (1 << BH_Delay))
get_blocks_flags |= EXT4_GET_BLOCKS_DELALLOC_RESERVE;
+
blks = ext4_map_blocks(handle, mpd->inode, &map, get_blocks_flags);
if (blks < 0) {
struct super_block *sb = mpd->inode->i_sb;
diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index 968ca93..6fea87d 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -81,6 +81,7 @@ static int ext4_feature_set_ok(struct super_block *sb, int readonly);
static void ext4_destroy_lazyinit_thread(void);
static void ext4_unregister_li_request(struct super_block *sb);
static void ext4_clear_request_list(void);
+static int ext4_reserve_clusters(struct ext4_sb_info *, ext4_fsblk_t);
#if !defined(CONFIG_EXT2_FS) && !defined(CONFIG_EXT2_FS_MODULE) && defined(CONFIG_EXT4_USE_FOR_EXT23)
static struct file_system_type ext2_fs_type = {
@@ -2382,6 +2383,17 @@ struct ext4_attr {
int offset;
};
+static int parse_strtoull(const char *buf,
+ unsigned long long max, unsigned long long *value)
+{
+ int ret;
+
+ ret = kstrtoull(skip_spaces(buf), 0, value);
+ if (!ret && *value > max)
+ ret = -EINVAL;
+ return ret;
+}
+
static int parse_strtoul(const char *buf,
unsigned long max, unsigned long *value)
{
@@ -2466,6 +2478,27 @@ static ssize_t sbi_ui_store(struct ext4_attr *a,
return count;
}
+static ssize_t reserved_clusters_show(struct ext4_attr *a,
+ struct ext4_sb_info *sbi, char *buf)
+{
+ return snprintf(buf, PAGE_SIZE, "%llu\n",
+ (unsigned long long) atomic64_read(&sbi->s_resv_clusters));
+}
+
+static ssize_t reserved_clusters_store(struct ext4_attr *a,
+ struct ext4_sb_info *sbi,
+ const char *buf, size_t count)
+{
+ unsigned long long val;
+ int ret;
+
+ if (parse_strtoull(buf, -1ULL, &val))
+ return -EINVAL;
+ ret = ext4_reserve_clusters(sbi, val);
+
+ return ret ? ret : count;
+}
+
static ssize_t trigger_test_error(struct ext4_attr *a,
struct ext4_sb_info *sbi,
const char *buf, size_t count)
@@ -2503,6 +2536,7 @@ static struct ext4_attr ext4_attr_##name = __ATTR(name, mode, show, store)
EXT4_RO_ATTR(delayed_allocation_blocks);
EXT4_RO_ATTR(session_write_kbytes);
EXT4_RO_ATTR(lifetime_write_kbytes);
+EXT4_RW_ATTR(reserved_clusters);
EXT4_ATTR_OFFSET(inode_readahead_blks, 0644, sbi_ui_show,
inode_readahead_blks_store, s_inode_readahead_blks);
EXT4_RW_ATTR_SBI_UI(inode_goal, s_inode_goal);
@@ -2520,6 +2554,7 @@ static struct attribute *ext4_attrs[] = {
ATTR_LIST(delayed_allocation_blocks),
ATTR_LIST(session_write_kbytes),
ATTR_LIST(lifetime_write_kbytes),
+ ATTR_LIST(reserved_clusters),
ATTR_LIST(inode_readahead_blks),
ATTR_LIST(inode_goal),
ATTR_LIST(mb_stats),
@@ -3195,6 +3230,40 @@ int ext4_calculate_overhead(struct super_block *sb)
return 0;
}
+
+static ext4_fsblk_t ext4_calculate_resv_clusters(struct ext4_sb_info *sbi)
+{
+ ext4_fsblk_t resv_clusters;
+
+ /*
+ * By default we reserve 2% or 4096 clusters, whichever is smaller.
+ * This should cover the situations where we can not afford to run
+ * out of space like for example punch hole, or converting
+ * uninitialized extents in delalloc path. In most cases such
+ * allocation would require 1, or 2 blocks, higher numbers are
+ * very rare.
+ */
+ resv_clusters = ext4_blocks_count(sbi->s_es) >> sbi->s_cluster_bits;
+
+ do_div(resv_clusters, 50);
+ resv_clusters = min_t(ext4_fsblk_t, resv_clusters, 4096);
+
+ return resv_clusters;
+}
+
+
+static int ext4_reserve_clusters(struct ext4_sb_info *sbi, ext4_fsblk_t count)
+{
+ ext4_fsblk_t clusters = ext4_blocks_count(sbi->s_es) >>
+ sbi->s_cluster_bits;
+
+ if (count >= clusters)
+ return -EINVAL;
+
+ atomic64_set(&sbi->s_resv_clusters, count);
+ return 0;
+}
+
static int ext4_fill_super(struct super_block *sb, void *data, int silent)
{
char *orig_data = kstrdup(data, GFP_KERNEL);
@@ -3918,6 +3987,13 @@ no_journal:
"available");
}
+ err = ext4_reserve_clusters(sbi, ext4_calculate_resv_clusters(sbi));
+ if (err) {
+ ext4_msg(sb, KERN_ERR, "failed to reserve %llu clusters for "
+ "reserved pool", ext4_calculate_resv_clusters(sbi));
+ goto failed_mount4a;
+ }
+
err = ext4_setup_system_zone(sb);
if (err) {
ext4_msg(sb, KERN_ERR, "failed to initialize system "
@@ -4750,9 +4826,10 @@ static int ext4_statfs(struct dentry *dentry, struct kstatfs *buf)
struct super_block *sb = dentry->d_sb;
struct ext4_sb_info *sbi = EXT4_SB(sb);
struct ext4_super_block *es = sbi->s_es;
- ext4_fsblk_t overhead = 0;
+ ext4_fsblk_t overhead = 0, resv_blocks;
u64 fsid;
s64 bfree;
+ resv_blocks = EXT4_C2B(sbi, atomic64_read(&sbi->s_resv_clusters));
if (!test_opt(sb, MINIX_DF))
overhead = sbi->s_overhead;
@@ -4764,8 +4841,9 @@ static int ext4_statfs(struct dentry *dentry, struct kstatfs *buf)
percpu_counter_sum_positive(&sbi->s_dirtyclusters_counter);
/* prevent underflow in case that few free space is available */
buf->f_bfree = EXT4_C2B(sbi, max_t(s64, bfree, 0));
- buf->f_bavail = buf->f_bfree - ext4_r_blocks_count(es);
- if (buf->f_bfree < ext4_r_blocks_count(es))
+ buf->f_bavail = buf->f_bfree -
+ (ext4_r_blocks_count(es) + resv_blocks);
+ if (buf->f_bfree < (ext4_r_blocks_count(es) + resv_blocks))
buf->f_bavail = 0;
buf->f_files = le32_to_cpu(es->s_inodes_count);
buf->f_ffree = percpu_counter_sum_positive(&sbi->s_freeinodes_counter);
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