| Message ID | 3338514d98370498d49ebc297a9b6d48a55282b8.1730286164.git.ritesh.list@gmail.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | ext4: Add atomic writes support for DIO | expand |
On Wed, Oct 30, 2024 at 09:27:38PM +0530, Ritesh Harjani (IBM) wrote: > This patch adds base support for atomic writes via statx getattr. > On bs < ps systems, we can create FS with say bs of 16k. That means > both atomic write min and max unit can be set to 16k for supporting > atomic writes. > > Co-developed-by: Ojaswin Mujoo <ojaswin@linux.ibm.com> > Signed-off-by: Ojaswin Mujoo <ojaswin@linux.ibm.com> > Signed-off-by: Ritesh Harjani (IBM) <ritesh.list@gmail.com> > --- > fs/ext4/ext4.h | 9 +++++++++ > fs/ext4/inode.c | 14 ++++++++++++++ > fs/ext4/super.c | 31 +++++++++++++++++++++++++++++++ > 3 files changed, 54 insertions(+) > > diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h > index 44b0d418143c..6ee49aaacd2b 100644 > --- a/fs/ext4/ext4.h > +++ b/fs/ext4/ext4.h > @@ -1729,6 +1729,10 @@ struct ext4_sb_info { > */ > struct work_struct s_sb_upd_work; > > + /* Atomic write unit values in bytes */ > + unsigned int s_awu_min; > + unsigned int s_awu_max; > + > /* Ext4 fast commit sub transaction ID */ > atomic_t s_fc_subtid; > > @@ -3855,6 +3859,11 @@ static inline int ext4_buffer_uptodate(struct buffer_head *bh) > return buffer_uptodate(bh); > } > > +static inline bool ext4_can_atomic_write(struct super_block *sb) > +{ > + return EXT4_SB(sb)->s_awu_min > 0; Huh, I was expecting you to stick to passing in the struct inode, and then you end up with: static inline bool ext4_can_atomic_write(struct inode *inode) { return S_ISREG(inode->i_mode) && EXT4_SB(inode->i_sb)->s_awu_min > 0); } > +} > + > extern int ext4_block_write_begin(handle_t *handle, struct folio *folio, > loff_t pos, unsigned len, > get_block_t *get_block); > diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c > index 54bdd4884fe6..fcdee27b9aa2 100644 > --- a/fs/ext4/inode.c > +++ b/fs/ext4/inode.c > @@ -5578,6 +5578,20 @@ int ext4_getattr(struct mnt_idmap *idmap, const struct path *path, > } > } > > + if (S_ISREG(inode->i_mode) && (request_mask & STATX_WRITE_ATOMIC)) { ...and then the callsites become: if (request_mask & STATX_WRITE_ATOMIC) { unsigned int awu_min = 0, awu_max = 0; if (ext4_can_atomic_write(inode)) { awu_min = sbi->s_awu_min; awu_max = sbi->s_awu_max; } generic_fill_statx_atomic_writes(stat, awu_min, awu_max); } (I forget, is it bad if statx to a directory returns STATX_WRITE_ATOMIC even with awu_{min,max} set to zero?) Other than that nit, this looks good to me. --D > + struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb); > + unsigned int awu_min, awu_max; > + > + if (ext4_can_atomic_write(inode->i_sb)) { > + awu_min = sbi->s_awu_min; > + awu_max = sbi->s_awu_max; > + } else { > + awu_min = awu_max = 0; > + } > + > + generic_fill_statx_atomic_writes(stat, awu_min, awu_max); > + } > + > flags = ei->i_flags & EXT4_FL_USER_VISIBLE; > if (flags & EXT4_APPEND_FL) > stat->attributes |= STATX_ATTR_APPEND; > diff --git a/fs/ext4/super.c b/fs/ext4/super.c > index 16a4ce704460..ebe1660bd840 100644 > --- a/fs/ext4/super.c > +++ b/fs/ext4/super.c > @@ -4425,6 +4425,36 @@ static int ext4_handle_clustersize(struct super_block *sb) > return 0; > } > > +/* > + * ext4_atomic_write_init: Initializes filesystem min & max atomic write units. > + * @sb: super block > + * TODO: Later add support for bigalloc > + */ > +static void ext4_atomic_write_init(struct super_block *sb) > +{ > + struct ext4_sb_info *sbi = EXT4_SB(sb); > + struct block_device *bdev = sb->s_bdev; > + > + if (!bdev_can_atomic_write(bdev)) > + return; > + > + if (!ext4_has_feature_extents(sb)) > + return; > + > + sbi->s_awu_min = max(sb->s_blocksize, > + bdev_atomic_write_unit_min_bytes(bdev)); > + sbi->s_awu_max = min(sb->s_blocksize, > + bdev_atomic_write_unit_max_bytes(bdev)); > + if (sbi->s_awu_min && sbi->s_awu_max && > + sbi->s_awu_min <= sbi->s_awu_max) { > + ext4_msg(sb, KERN_NOTICE, "Supports (experimental) DIO atomic writes awu_min: %u, awu_max: %u", > + sbi->s_awu_min, sbi->s_awu_max); > + } else { > + sbi->s_awu_min = 0; > + sbi->s_awu_max = 0; > + } > +} > + > static void ext4_fast_commit_init(struct super_block *sb) > { > struct ext4_sb_info *sbi = EXT4_SB(sb); > @@ -5336,6 +5366,7 @@ static int __ext4_fill_super(struct fs_context *fc, struct super_block *sb) > > spin_lock_init(&sbi->s_bdev_wb_lock); > > + ext4_atomic_write_init(sb); > ext4_fast_commit_init(sb); > > sb->s_root = NULL; > -- > 2.46.0 > >
diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h index 44b0d418143c..6ee49aaacd2b 100644 --- a/fs/ext4/ext4.h +++ b/fs/ext4/ext4.h @@ -1729,6 +1729,10 @@ struct ext4_sb_info { */ struct work_struct s_sb_upd_work; + /* Atomic write unit values in bytes */ + unsigned int s_awu_min; + unsigned int s_awu_max; + /* Ext4 fast commit sub transaction ID */ atomic_t s_fc_subtid; @@ -3855,6 +3859,11 @@ static inline int ext4_buffer_uptodate(struct buffer_head *bh) return buffer_uptodate(bh); } +static inline bool ext4_can_atomic_write(struct super_block *sb) +{ + return EXT4_SB(sb)->s_awu_min > 0; +} + extern int ext4_block_write_begin(handle_t *handle, struct folio *folio, loff_t pos, unsigned len, get_block_t *get_block); diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c index 54bdd4884fe6..fcdee27b9aa2 100644 --- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c @@ -5578,6 +5578,20 @@ int ext4_getattr(struct mnt_idmap *idmap, const struct path *path, } } + if (S_ISREG(inode->i_mode) && (request_mask & STATX_WRITE_ATOMIC)) { + struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb); + unsigned int awu_min, awu_max; + + if (ext4_can_atomic_write(inode->i_sb)) { + awu_min = sbi->s_awu_min; + awu_max = sbi->s_awu_max; + } else { + awu_min = awu_max = 0; + } + + generic_fill_statx_atomic_writes(stat, awu_min, awu_max); + } + flags = ei->i_flags & EXT4_FL_USER_VISIBLE; if (flags & EXT4_APPEND_FL) stat->attributes |= STATX_ATTR_APPEND; diff --git a/fs/ext4/super.c b/fs/ext4/super.c index 16a4ce704460..ebe1660bd840 100644 --- a/fs/ext4/super.c +++ b/fs/ext4/super.c @@ -4425,6 +4425,36 @@ static int ext4_handle_clustersize(struct super_block *sb) return 0; } +/* + * ext4_atomic_write_init: Initializes filesystem min & max atomic write units. + * @sb: super block + * TODO: Later add support for bigalloc + */ +static void ext4_atomic_write_init(struct super_block *sb) +{ + struct ext4_sb_info *sbi = EXT4_SB(sb); + struct block_device *bdev = sb->s_bdev; + + if (!bdev_can_atomic_write(bdev)) + return; + + if (!ext4_has_feature_extents(sb)) + return; + + sbi->s_awu_min = max(sb->s_blocksize, + bdev_atomic_write_unit_min_bytes(bdev)); + sbi->s_awu_max = min(sb->s_blocksize, + bdev_atomic_write_unit_max_bytes(bdev)); + if (sbi->s_awu_min && sbi->s_awu_max && + sbi->s_awu_min <= sbi->s_awu_max) { + ext4_msg(sb, KERN_NOTICE, "Supports (experimental) DIO atomic writes awu_min: %u, awu_max: %u", + sbi->s_awu_min, sbi->s_awu_max); + } else { + sbi->s_awu_min = 0; + sbi->s_awu_max = 0; + } +} + static void ext4_fast_commit_init(struct super_block *sb) { struct ext4_sb_info *sbi = EXT4_SB(sb); @@ -5336,6 +5366,7 @@ static int __ext4_fill_super(struct fs_context *fc, struct super_block *sb) spin_lock_init(&sbi->s_bdev_wb_lock); + ext4_atomic_write_init(sb); ext4_fast_commit_init(sb); sb->s_root = NULL;