ext4: add fast_commit feature and handling for extended mount options

We are running out of mount option bits. Add handling for using
s_mount_opt2. Add ext4 and jbd2 fast commit feature flag and also add
ability to turn off the fast commit feature in Ext4.

Signed-off-by: Harshad Shirwadkar <harshadshirwadkar@gmail.com>
Link: https://lore.kernel.org/r/20201015203802.3597742-3-harshadshirwadkar@gmail.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index 1879531..02d7dc3 100644 (file)
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -1213,6 +1213,8 @@ struct ext4_inode_info {
 #define EXT4_MOUNT2_EXPLICIT_JOURNAL_CHECKSUM  0x00000008 /* User explicitly
                                                specified journal checksum */
 
+#define EXT4_MOUNT2_JOURNAL_FAST_COMMIT        0x00000010 /* Journal fast commit */
+
 #define clear_opt(sb, opt)             EXT4_SB(sb)->s_mount_opt &= \
                                                ~EXT4_MOUNT_##opt
 #define set_opt(sb, opt)               EXT4_SB(sb)->s_mount_opt |= \
@@ -1813,6 +1815,7 @@ static inline bool ext4_verity_in_progress(struct inode *inode)
 #define EXT4_FEATURE_COMPAT_RESIZE_INODE       0x0010
 #define EXT4_FEATURE_COMPAT_DIR_INDEX          0x0020
 #define EXT4_FEATURE_COMPAT_SPARSE_SUPER2      0x0200
+#define EXT4_FEATURE_COMPAT_FAST_COMMIT                0x0400
 #define EXT4_FEATURE_COMPAT_STABLE_INODES      0x0800
 
 #define EXT4_FEATURE_RO_COMPAT_SPARSE_SUPER    0x0001
@@ -1915,6 +1918,7 @@ EXT4_FEATURE_COMPAT_FUNCS(xattr,          EXT_ATTR)
 EXT4_FEATURE_COMPAT_FUNCS(resize_inode,                RESIZE_INODE)
 EXT4_FEATURE_COMPAT_FUNCS(dir_index,           DIR_INDEX)
 EXT4_FEATURE_COMPAT_FUNCS(sparse_super2,       SPARSE_SUPER2)
+EXT4_FEATURE_COMPAT_FUNCS(fast_commit,         FAST_COMMIT)
 EXT4_FEATURE_COMPAT_FUNCS(stable_inodes,       STABLE_INODES)
 
 EXT4_FEATURE_RO_COMPAT_FUNCS(sparse_super,     SPARSE_SUPER)

diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index f997fc9..66423c5 100644 (file)
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -1709,7 +1709,7 @@ enum {
        Opt_dioread_nolock, Opt_dioread_lock,
        Opt_discard, Opt_nodiscard, Opt_init_itable, Opt_noinit_itable,
        Opt_max_dir_size_kb, Opt_nojournal_checksum, Opt_nombcache,
-       Opt_prefetch_block_bitmaps,
+       Opt_prefetch_block_bitmaps, Opt_no_fc,
 };
 
 static const match_table_t tokens = {
@@ -1796,6 +1796,7 @@ static const match_table_t tokens = {
        {Opt_init_itable, "init_itable=%u"},
        {Opt_init_itable, "init_itable"},
        {Opt_noinit_itable, "noinit_itable"},
+       {Opt_no_fc, "no_fc"},
        {Opt_max_dir_size_kb, "max_dir_size_kb=%u"},
        {Opt_test_dummy_encryption, "test_dummy_encryption=%s"},
        {Opt_test_dummy_encryption, "test_dummy_encryption"},
@@ -1922,6 +1923,7 @@ static int clear_qf_name(struct super_block *sb, int qtype)
 #define MOPT_EXT4_ONLY (MOPT_NO_EXT2 | MOPT_NO_EXT3)
 #define MOPT_STRING    0x0400
 #define MOPT_SKIP      0x0800
+#define        MOPT_2          0x1000
 
 static const struct mount_opts {
        int     token;
@@ -2022,6 +2024,8 @@ static const struct mount_opts {
        {Opt_nombcache, EXT4_MOUNT_NO_MBCACHE, MOPT_SET},
        {Opt_prefetch_block_bitmaps, EXT4_MOUNT_PREFETCH_BLOCK_BITMAPS,
         MOPT_SET},
+       {Opt_no_fc, EXT4_MOUNT2_JOURNAL_FAST_COMMIT,
+        MOPT_CLEAR | MOPT_2 | MOPT_EXT4_ONLY},
        {Opt_err, 0, 0}
 };
 
@@ -2398,10 +2402,17 @@ static int handle_mount_opt(struct super_block *sb, char *opt, int token,
                        WARN_ON(1);
                        return -1;
                }
-               if (arg != 0)
-                       sbi->s_mount_opt |= m->mount_opt;
-               else
-                       sbi->s_mount_opt &= ~m->mount_opt;
+               if (m->flags & MOPT_2) {
+                       if (arg != 0)
+                               sbi->s_mount_opt2 |= m->mount_opt;
+                       else
+                               sbi->s_mount_opt2 &= ~m->mount_opt;
+               } else {
+                       if (arg != 0)
+                               sbi->s_mount_opt |= m->mount_opt;
+                       else
+                               sbi->s_mount_opt &= ~m->mount_opt;
+               }
        }
        return 1;
 }
@@ -2618,6 +2629,9 @@ static int _ext4_show_options(struct seq_file *seq, struct super_block *sb,
                SEQ_OPTS_PUTS("dax=inode");
        }
 
+       if (test_opt2(sb, JOURNAL_FAST_COMMIT))
+               SEQ_OPTS_PUTS("fast_commit");
+
        ext4_show_quota_options(seq, sb);
        return 0;
 }
@@ -4121,6 +4135,8 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent)
 #ifdef CONFIG_EXT4_FS_POSIX_ACL
        set_opt(sb, POSIX_ACL);
 #endif
+       if (ext4_has_feature_fast_commit(sb))
+               set_opt2(sb, JOURNAL_FAST_COMMIT);
        /* don't forget to enable journal_csum when metadata_csum is enabled. */
        if (ext4_has_metadata_csum(sb))
                set_opt(sb, JOURNAL_CHECKSUM);
@@ -4777,6 +4793,7 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent)
                sbi->s_def_mount_opt &= ~EXT4_MOUNT_JOURNAL_CHECKSUM;
                clear_opt(sb, JOURNAL_CHECKSUM);
                clear_opt(sb, DATA_FLAGS);
+               clear_opt2(sb, JOURNAL_FAST_COMMIT);
                sbi->s_journal = NULL;
                needs_recovery = 0;
                goto no_journal;

diff --git a/include/linux/jbd2.h b/include/linux/jbd2.h
index 04afa6d..0685cc9 100644 (file)
--- a/include/linux/jbd2.h
+++ b/include/linux/jbd2.h
@@ -289,6 +289,7 @@ typedef struct journal_superblock_s
 #define JBD2_FEATURE_INCOMPAT_ASYNC_COMMIT     0x00000004
 #define JBD2_FEATURE_INCOMPAT_CSUM_V2          0x00000008
 #define JBD2_FEATURE_INCOMPAT_CSUM_V3          0x00000010
+#define JBD2_FEATURE_INCOMPAT_FAST_COMMIT      0x00000020
 
 /* See "journal feature predicate functions" below */
 
@@ -299,7 +300,8 @@ typedef struct journal_superblock_s
                                        JBD2_FEATURE_INCOMPAT_64BIT | \
                                        JBD2_FEATURE_INCOMPAT_ASYNC_COMMIT | \
                                        JBD2_FEATURE_INCOMPAT_CSUM_V2 | \
-                                       JBD2_FEATURE_INCOMPAT_CSUM_V3)
+                                       JBD2_FEATURE_INCOMPAT_CSUM_V3 | \
+                                       JBD2_FEATURE_INCOMPAT_FAST_COMMIT)
 
 #ifdef __KERNEL__
 
@@ -1263,6 +1265,7 @@ JBD2_FEATURE_INCOMPAT_FUNCS(64bit,                64BIT)
 JBD2_FEATURE_INCOMPAT_FUNCS(async_commit,      ASYNC_COMMIT)
 JBD2_FEATURE_INCOMPAT_FUNCS(csum2,             CSUM_V2)
 JBD2_FEATURE_INCOMPAT_FUNCS(csum3,             CSUM_V3)
+JBD2_FEATURE_INCOMPAT_FUNCS(fast_commit,       FAST_COMMIT)
 
 /*
  * Journal flag definitions