[PATCH RFC 7/8] ext4: Add mount option for provisioning blocks during allocations

Sarthak Kukreti
2022-09-15T16:49:59Z

From: Sarthak Kukreti <sarthakkukreti@chromium.org>

Add a mount option that sets the default provisioning mode for
all files within the filesystem.

Signed-off-by: Sarthak Kukreti <sarthakkukreti@chromium.org>
---
fs/ext4/ext4.h | 1 +
fs/ext4/extents.c | 7 +++++++
fs/ext4/super.c | 7 +++++++
3 files changed, 15 insertions(+)

diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index ec0871e687c1..75f6e7f2f90b 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -1271,6 +1271,7 @@ struct ext4_inode_info {
#define EXT4_MOUNT2_MB_OPTIMIZE_SCAN 0x00000080 /* Optimize group
* scanning in mballoc
*/
+#define EXT4_MOUNT2_PROVISION 0x00000100 /* Provision while allocating file blocks */

#define clear_opt(sb, opt) EXT4_SB(sb)->s_mount_opt &= \
~EXT4_MOUNT_##opt
diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
index 7a096144b7f8..746213b5ec3d 100644
--- a/fs/ext4/extents.c
+++ b/fs/ext4/extents.c
@@ -4437,6 +4437,13 @@ static int ext4_alloc_file_blocks(struct file *file, ext4_lblk_t offset,
unsigned int credits;
loff_t epos;

+ /*
+ * Attempt to provision file blocks if the mount is mounted with
+ * provision.
+ */
+ if (test_opt2(inode->i_sb, PROVISION))
+ flags |= EXT4_GET_BLOCKS_PROVISION;
+
BUG_ON(!ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS));
map.m_lblk = offset;
map.m_len = len;
diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index 9a66abcca1a8..5ece1868f332 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -1596,6 +1596,7 @@ enum {
Opt_max_dir_size_kb, Opt_nojournal_checksum, Opt_nombcache,
Opt_no_prefetch_block_bitmaps, Opt_mb_optimize_scan,
Opt_errors, Opt_data, Opt_data_err, Opt_jqfmt, Opt_dax_type,
+ Opt_provision, Opt_noprovision,
#ifdef CONFIG_EXT4_DEBUG
Opt_fc_debug_max_replay, Opt_fc_debug_force
#endif
@@ -1744,6 +1745,8 @@ static const struct fs_parameter_spec ext4_param_specs[] = {
fsparam_flag ("reservation", Opt_removed), /* mount option from ext2/3 */
fsparam_flag ("noreservation", Opt_removed), /* mount option from ext2/3 */
fsparam_u32 ("journal", Opt_removed), /* mount option from ext2/3 */
+ fsparam_flag ("discard", Opt_provision),
+ fsparam_flag ("noprovision", Opt_noprovision),
{}
};

@@ -1840,6 +1843,8 @@ static const struct mount_opts {
{Opt_nombcache, EXT4_MOUNT_NO_MBCACHE, MOPT_SET},
{Opt_no_prefetch_block_bitmaps, EXT4_MOUNT_NO_PREFETCH_BLOCK_BITMAPS,
MOPT_SET},
+ {Opt_provision, EXT4_MOUNT2_PROVISION, MOPT_SET | MOPT_2},
+ {Opt_noprovision, EXT4_MOUNT2_PROVISION, MOPT_CLEAR | MOPT_2},
#ifdef CONFIG_EXT4_DEBUG
{Opt_fc_debug_force, EXT4_MOUNT2_JOURNAL_FAST_COMMIT,
MOPT_SET | MOPT_2 | MOPT_EXT4_ONLY},
@@ -3010,6 +3015,8 @@ static int _ext4_show_options(struct seq_file *seq, struct super_block *sb,
SEQ_OPTS_PUTS("dax=never");
} else if (test_opt2(sb, DAX_INODE)) {
SEQ_OPTS_PUTS("dax=inode");
+ } else if (test_opt2(sb, PROVISION)) {
+ SEQ_OPTS_PUTS("provision");
}

if (sbi->s_groups_count >= MB_DEFAULT_LINEAR_SCAN_THRESHOLD &&
--
2.31.0