[RFC][PATCH V2 3/5] ext4: add EXT4_IOC_GET_PA to get inode PA information
From: Kazuya Mio <hidden>
Date: 2010-08-25 09:01:05
Also in:
linux-fsdevel
Subsystem:
ext4 file system, filesystems (vfs and infrastructure), the rest · Maintainers:
"Theodore Ts'o", Alexander Viro, Christian Brauner, Linus Torvalds
This ioctl gets the information of all inode PAs in the target inode.
The interface of this ioctl is like FS_IOC_FIEMAP. If we call this ioctl, we
get the array of struct ext4_prealloc_info that stores the information of inode
PA.
INTERFACE
-----------
#define EXT4_IOC_GET_PA _IOWR('f', 17, struct ext4_prealloc_list)
struct ext4_prealloc_list {
__u32 pl_count; /* size of pl_space array (in) */
__u32 pl_mapped; /* number of PAs that were mapped (out) */
__u32 pl_entries; /* number of PAs the inode has (out) */
struct ext4_prealloc_info pl_space[0]; /* array of mapped PAs (out) */
};
pl_count specifies the number of elements in the pl_space[] array that can be
used to return inode PAs. If pl_count is zero, no inode PAs will be returned.
Moreover, if pl_count is set the value that is better than the number of
elements in the pl_space array, this ioctl returns EFAULT.
pl_mapped shows the number of getting inode PAs, and pl_entries shows the
number of inode PAs in the target inode. You can confirm that we could get all
inode PAs in the target inode by comparison with pl_mapped and pl_entries.
Signed-off-by: Kazuya Mio <redacted>
Signed-off-by: Akira Fujita <redacted>
---
fs/ext4/ext4.h | 11 +++++++++++
fs/ext4/ioctl.c | 33 +++++++++++++++++++++++++++++++++
fs/ext4/mballoc.c | 44 ++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 88 insertions(+)
diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index 550c61b..a7cb560 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h@@ -147,6 +147,14 @@ struct ext4_prealloc_info { __u16 pi_flags; /* flags for the inode PA setting ioctl (in) */ }; +/* inode PA list */ +struct ext4_prealloc_list { + __u32 pl_count; /* size of pl_space array (in) */ + __u32 pl_mapped; /* number of PAs that were mapped (out) */ + __u32 pl_entries; /* number of PAs the inode has (out) */ + struct ext4_prealloc_info pl_space[0]; /* array of mapped PAs (out) */ +}; + /* * Logical to physical block mapping, used by ext4_map_blocks() *
@@ -534,6 +542,7 @@ struct ext4_new_group_data { #define EXT4_IOC_ALLOC_DA_BLKS _IO('f', 12) #define EXT4_IOC_MOVE_EXT _IOWR('f', 15, struct move_extent) #define EXT4_IOC_CONTROL_PA _IOWR('f', 16, struct ext4_prealloc_info) +#define EXT4_IOC_GET_PA _IOWR('f', 17, struct ext4_prealloc_list) #if defined(__KERNEL__) && defined(CONFIG_COMPAT) /*
@@ -1654,6 +1663,8 @@ extern void ext4_mb_put_buddy_cache_lock(struct super_block *, ext4_group_t, int); extern int ext4_mb_control_pa(struct inode *inode, struct ext4_prealloc_info *pi); +extern int ext4_mb_get_pa(struct inode *inode, struct ext4_prealloc_list *pl, + struct ext4_prealloc_info *dest); /* inode.c */ struct buffer_head *ext4_getblk(handle_t *, struct inode *,
diff --git a/fs/ext4/ioctl.c b/fs/ext4/ioctl.c
index 631ae01..352cb35 100644
--- a/fs/ext4/ioctl.c
+++ b/fs/ext4/ioctl.c@@ -424,6 +424,38 @@ mext_out: return err; } + case EXT4_IOC_GET_PA: + { + struct ext4_prealloc_list pl; + struct ext4_prealloc_info *dest; + int err; + + if (!S_ISREG(inode->i_mode)) + return -EINVAL; + if (!(filp->f_mode & FMODE_READ)) + return -EBADF; + + if (copy_from_user(&pl, + (struct ext4_prealloc_list __user *)arg, sizeof(pl))) + return -EFAULT; + + dest = (struct ext4_prealloc_info *)(arg + sizeof(pl)); + if (!access_ok(VERIFY_WRITE, + (struct ext4_prealloc_info __force __user *)dest, + pl.pl_count * sizeof(struct ext4_prealloc_info))) + return -EFAULT; + + err = ext4_mb_get_pa(inode, &pl, dest); + + if (err) + return err; + + if (copy_to_user((struct ext4_prealloc_list __user *)arg, + &pl, sizeof(pl))) + return -EFAULT; + return err; + } + default: return -ENOTTY; }
@@ -492,6 +524,7 @@ long ext4_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg) case EXT4_IOC_MOVE_EXT: case EXT4_IOC_DEBUG_DELALLOC: case EXT4_IOC_CONTROL_PA: + case EXT4_IOC_GET_PA: break; default: return -ENOIOCTLCMD;
diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
index 9a33c33..a412e72 100644
--- a/fs/ext4/mballoc.c
+++ b/fs/ext4/mballoc.c@@ -5089,3 +5089,47 @@ out: return err1; } +/** + * ext4_mb_get_pa - Pass inode PA information to user space + * + * @inode: target inode + * @pl: information of the inode PA list (in/out) + * @dest: user space address where PAs' information is written to + * + * Return 0 if success or error code on failure. + */ +int ext4_mb_get_pa(struct inode *inode, struct ext4_prealloc_list *pl, + struct ext4_prealloc_info *dest) +{ + struct ext4_inode_info *ei = EXT4_I(inode); + struct ext4_prealloc_space *pa; + struct ext4_prealloc_info pi; + + pl->pl_entries = 0; + pl->pl_mapped = 0; + + rcu_read_lock(); + list_for_each_entry_rcu(pa, &ei->i_prealloc_list, pa_inode_list) { + pl->pl_entries++; + if (pl->pl_mapped < pl->pl_count) { + memset(&pi, 0, sizeof(pi)); + pi.pi_pstart = pa->pa_pstart; + pi.pi_lstart = pa->pa_lstart; + pi.pi_len = pa->pa_len; + pi.pi_free = pa->pa_free; + + rcu_read_unlock(); + if (copy_to_user( + (struct ext4_prealloc_info __force __user *)dest, + &pi, sizeof(pi))) { + return -EFAULT; + } + dest++; + pl->pl_mapped++; + rcu_read_lock(); + } + } + rcu_read_unlock(); + + return 0; +}