Hi Ryusuke,
I've modified the patch with taking into account all your remarks.
v1->v2
* Change description of NILFS_IOCTL_SYNC ioctl in documentation file
Documentation/filesystems/nilfs2.txt.
* Change description of nilfs_ioctl_move_inode_block().
* Change description of nilfs_ioctl_sync().
With the best regards,
Vyacheslav Dubeyko.
---
From: Vyacheslav Dubeyko <slava@xxxxxxxxxxx>
Subject: [PATCH v2] nilfs2: add comments for ioctls
This patch adds comments for ioctls in fs/nilfs2/ioctl.c
file and describes NILFS2 specific ioctls in documentation
file Documentation/filesystems/nilfs2.txt.
Signed-off-by: Vyacheslav Dubeyko <slava@xxxxxxxxxxx>
Reviewed-by: Ryusuke Konishi <konishi.ryusuke@xxxxxxxxxxxxx>
---
Documentation/filesystems/nilfs2.txt | 56 ++++++
fs/nilfs2/ioctl.c | 363 +++++++++++++++++++++++++++++++++-
2 files changed, 418 insertions(+), 1 deletion(-)
diff --git a/Documentation/filesystems/nilfs2.txt b/Documentation/filesystems/nilfs2.txt
index 873a2ab..06887d4 100644
--- a/Documentation/filesystems/nilfs2.txt
+++ b/Documentation/filesystems/nilfs2.txt
@@ -81,6 +81,62 @@ nodiscard(*) The discard/TRIM commands are sent to the underlying
block device when blocks are freed. This is useful
for SSD devices and sparse/thinly-provisioned LUNs.
+Ioctls
+======
+
+There is some NILFS2 specific functionality which can be accessed by applications
+through the system call interfaces. The list of all NILFS2 specific ioctls are
+shown in the table below.
+
+Table of NILFS2 specific ioctls
+..............................................................................
+ Ioctl Description
+ NILFS_IOCTL_CHANGE_CPMODE Change mode of given checkpoint between
+ checkpoint and snapshot state. This ioctl is
+ used in chcp and mkcp utilities.
+
+ NILFS_IOCTL_DELETE_CHECKPOINT Remove checkpoint from NILFS2 file system.
+ This ioctl is used in rmcp utility.
+
+ NILFS_IOCTL_GET_CPINFO Return info about requested checkpoints. This
+ ioctl is used in lscp utility and by
+ nilfs_cleanerd daemon.
+
+ NILFS_IOCTL_GET_CPSTAT Return checkpoints statistics. This ioctl is
+ used by lscp, rmcp utilities and by
+ nilfs_cleanerd daemon.
+
+ NILFS_IOCTL_GET_SUINFO Return segment usage info about requested
+ segments. This ioctl is used in lssu,
+ nilfs_resize utilities and by nilfs_cleanerd
+ daemon.
+
+ NILFS_IOCTL_GET_SUSTAT Return segment usage statistics. This ioctl
+ is used in lssu, nilfs_resize utilities and
+ by nilfs_cleanerd daemon.
+
+ NILFS_IOCTL_GET_VINFO Return information on virtual block addresses.
+ This ioctl is used by nilfs_cleanerd daemon.
+
+ NILFS_IOCTL_GET_BDESCS Return information about descriptors of disk
+ block numbers. This ioctl is used by
+ nilfs_cleanerd daemon.
+
+ NILFS_IOCTL_CLEAN_SEGMENTS Do garbage collection operation in the
+ environment of requested parameters from
+ userspace. This ioctl is used by
+ nilfs_cleanerd daemon.
+
+ NILFS_IOCTL_SYNC Make a checkpoint. This ioctl is used in
+ mkcp utility.
+
+ NILFS_IOCTL_RESIZE Resize NILFS2 volume. This ioctl is used
+ by nilfs_resize utility.
+
+ NILFS_IOCTL_SET_ALLOC_RANGE Define lower limit of segments in bytes and
+ upper limit of segments in bytes. This ioctl
+ is used by nilfs_resize utility.
+
NILFS2 usage
============
diff --git a/fs/nilfs2/ioctl.c b/fs/nilfs2/ioctl.c
index b44bdb2..75587e5 100644
--- a/fs/nilfs2/ioctl.c
+++ b/fs/nilfs2/ioctl.c
@@ -37,7 +37,26 @@
#include "sufile.h"
#include "dat.h"
-
+/**
+ * nilfs_ioctl_wrap_copy - wrapping function of get/set metadata info
+ * @nilfs: nilfs object
+ * @argv: vector of arguments from userspace
+ * @dir: set of direction flags
+ * @dofunc: concrete function of get/set metadata info
+ *
+ * Description: nilfs_ioctl_wrap_copy() gets/sets metadata info by means of
+ * calling dofunc() function on the basis of @argv argument.
+ *
+ * Return Value: On success, 0 is returned and requested metadata info
+ * is copied into userspace. On error, one of the following
+ * negative error codes is returned.
+ *
+ * %-EINVAL - Invalid arguments from userspace.
+ *
+ * %-ENOMEM - Insufficient amount of memory available.
+ *
+ * %-EFAULT - Failure during execution of requested operation.
+ */
static int nilfs_ioctl_wrap_copy(struct the_nilfs *nilfs,
struct nilfs_argv *argv, int dir,
ssize_t (*dofunc)(struct the_nilfs *,
@@ -99,6 +118,9 @@ static int nilfs_ioctl_wrap_copy(struct the_nilfs *nilfs,
return ret;
}
+/**
+ * nilfs_ioctl_getflags - ioctl to support lsattr
+ */
static int nilfs_ioctl_getflags(struct inode *inode, void __user *argp)
{
unsigned int flags = NILFS_I(inode)->i_flags & FS_FL_USER_VISIBLE;
@@ -106,6 +128,9 @@ static int nilfs_ioctl_getflags(struct inode *inode, void __user *argp)
return put_user(flags, (int __user *)argp);
}
+/**
+ * nilfs_ioctl_setflags - ioctl to support chattr
+ */
static int nilfs_ioctl_setflags(struct inode *inode, struct file *filp,
void __user *argp)
{
@@ -158,11 +183,33 @@ out:
return ret;
}
+/**
+ * nilfs_ioctl_getversion - get info about a file's version (generation number)
+ */
static int nilfs_ioctl_getversion(struct inode *inode, void __user *argp)
{
return put_user(inode->i_generation, (int __user *)argp);
}
+/**
+ * nilfs_ioctl_change_cpmode - change checkpoint mode (checkpoint/snapshot)
+ * @inode: inode object
+ * @filp: file object
+ * @cmd: ioctl's request code
+ * @argp: pointer on argument from userspace
+ *
+ * Description: nilfs_ioctl_change_cpmode() function changes mode of
+ * given checkpoint between checkpoint and snapshot state. This ioctl
+ * is used in chcp and mkcp utilities.
+ *
+ * Return Value: On success, 0 is returned and mode of a checkpoint is
+ * changed. On error, one of the following negative error codes
+ * is returned.
+ *
+ * %-EPERM - Operation not permitted.
+ *
+ * %-EFAULT - Failure during checkpoint mode changing.
+ */
static int nilfs_ioctl_change_cpmode(struct inode *inode, struct file *filp,
unsigned int cmd, void __user *argp)
{
@@ -198,6 +245,25 @@ out:
return ret;
}
+/**
+ * nilfs_ioctl_delete_checkpoint - remove checkpoint
+ * @inode: inode object
+ * @filp: file object
+ * @cmd: ioctl's request code
+ * @argp: pointer on argument from userspace
+ *
+ * Description: nilfs_ioctl_delete_checkpoint() function removes
+ * checkpoint from NILFS2 file system. This ioctl is used in rmcp
+ * utility.
+ *
+ * Return Value: On success, 0 is returned and a checkpoint is
+ * removed. On error, one of the following negative error codes
+ * is returned.
+ *
+ * %-EPERM - Operation not permitted.
+ *
+ * %-EFAULT - Failure during checkpoint removing.
+ */
static int
nilfs_ioctl_delete_checkpoint(struct inode *inode, struct file *filp,
unsigned int cmd, void __user *argp)
@@ -229,6 +295,21 @@ out:
return ret;
}
+/**
+ * nilfs_ioctl_do_get_cpinfo - callback method getting info about checkpoints
+ * @nilfs: nilfs object
+ * @posp: pointer on array of checkpoint's numbers
+ * @flags: checkpoint mode (checkpoint or snapshot)
+ * @buf: buffer for storing checkponts' info
+ * @size: size in bytes of one checkpoint info item in array
+ * @nmembs: number of checkpoints in array (numbers and infos)
+ *
+ * Description: nilfs_ioctl_do_get_cpinfo() function returns info about
+ * requested checkpoints. The NILFS_IOCTL_GET_CPINFO ioctl is used in
+ * lscp utility and by nilfs_cleanerd daemon.
+ *
+ * Return value: count of nilfs_cpinfo structures in output buffer.
+ */
static ssize_t
nilfs_ioctl_do_get_cpinfo(struct the_nilfs *nilfs, __u64 *posp, int flags,
void *buf, size_t size, size_t nmembs)
@@ -242,6 +323,27 @@ nilfs_ioctl_do_get_cpinfo(struct the_nilfs *nilfs, __u64 *posp, int flags,
return ret;
}
+/**
+ * nilfs_ioctl_get_cpstat - get checkpoints statistics
+ * @inode: inode object
+ * @filp: file object
+ * @cmd: ioctl's request code
+ * @argp: pointer on argument from userspace
+ *
+ * Description: nilfs_ioctl_get_cpstat() returns information about checkpoints.
+ * The NILFS_IOCTL_GET_CPSTAT ioctl is used by lscp, rmcp utilities
+ * and by nilfs_cleanerd daemon.
+ *
+ * Return Value: On success, 0 is returned, and checkpoints information is
+ * copied into userspace pointer @argp. On error, one of the following
+ * negative error codes is returned.
+ *
+ * %-EIO - I/O error.
+ *
+ * %-ENOMEM - Insufficient amount of memory available.
+ *
+ * %-EFAULT - Failure during getting checkpoints statistics.
+ */
static int nilfs_ioctl_get_cpstat(struct inode *inode, struct file *filp,
unsigned int cmd, void __user *argp)
{
@@ -260,6 +362,21 @@ static int nilfs_ioctl_get_cpstat(struct inode *inode, struct file *filp,
return ret;
}
+/**
+ * nilfs_ioctl_do_get_suinfo - callback method getting segment usage info
+ * @nilfs: nilfs object
+ * @posp: pointer on array of segment numbers
+ * @flags: *not used*
+ * @buf: buffer for storing suinfo array
+ * @size: size in bytes of one suinfo item in array
+ * @nmembs: count of segment numbers and suinfos in array
+ *
+ * Description: nilfs_ioctl_do_get_suinfo() function returns segment usage
+ * info about requested segments. The NILFS_IOCTL_GET_SUINFO ioctl is used
+ * in lssu, nilfs_resize utilities and by nilfs_cleanerd daemon.
+ *
+ * Return value: count of nilfs_suinfo structures in output buffer.
+ */
static ssize_t
nilfs_ioctl_do_get_suinfo(struct the_nilfs *nilfs, __u64 *posp, int flags,
void *buf, size_t size, size_t nmembs)
@@ -273,6 +390,27 @@ nilfs_ioctl_do_get_suinfo(struct the_nilfs *nilfs, __u64 *posp, int flags,
return ret;
}
+/**
+ * nilfs_ioctl_get_sustat - get segment usage statistics
+ * @inode: inode object
+ * @filp: file object
+ * @cmd: ioctl's request code
+ * @argp: pointer on argument from userspace
+ *
+ * Description: nilfs_ioctl_get_sustat() returns segment usage statistics.
+ * The NILFS_IOCTL_GET_SUSTAT ioctl is used in lssu, nilfs_resize utilities
+ * and by nilfs_cleanerd daemon.
+ *
+ * Return Value: On success, 0 is returned, and segment usage information is
+ * copied into userspace pointer @argp. On error, one of the following
+ * negative error codes is returned.
+ *
+ * %-EIO - I/O error.
+ *
+ * %-ENOMEM - Insufficient amount of memory available.
+ *
+ * %-EFAULT - Failure during getting segment usage statistics.
+ */
static int nilfs_ioctl_get_sustat(struct inode *inode, struct file *filp,
unsigned int cmd, void __user *argp)
{
@@ -291,6 +429,21 @@ static int nilfs_ioctl_get_sustat(struct inode *inode, struct file *filp,
return ret;
}
+/**
+ * nilfs_ioctl_do_get_vinfo - callback method getting virtual blocks info
+ * @nilfs: nilfs object
+ * @posp: *not used*
+ * @flags: *not used*
+ * @buf: buffer for storing array of nilfs_vinfo structures
+ * @size: size in bytes of one vinfo item in array
+ * @nmembs: count of vinfos in array
+ *
+ * Description: nilfs_ioctl_do_get_vinfo() function returns information
+ * on virtual block addresses. The NILFS_IOCTL_GET_VINFO ioctl is used
+ * by nilfs_cleanerd daemon.
+ *
+ * Return value: count of nilfs_vinfo structures in output buffer.
+ */
static ssize_t
nilfs_ioctl_do_get_vinfo(struct the_nilfs *nilfs, __u64 *posp, int flags,
void *buf, size_t size, size_t nmembs)
@@ -303,6 +456,21 @@ nilfs_ioctl_do_get_vinfo(struct the_nilfs *nilfs, __u64 *posp, int flags,
return ret;
}
+/**
+ * nilfs_ioctl_do_get_bdescs - callback method getting disk block descriptors
+ * @nilfs: nilfs object
+ * @posp: *not used*
+ * @flags: *not used*
+ * @buf: buffer for storing array of nilfs_bdesc structures
+ * @size: size in bytes of one bdesc item in array
+ * @nmembs: count of bdescs in array
+ *
+ * Description: nilfs_ioctl_do_get_bdescs() function returns information
+ * about descriptors of disk block numbers. The NILFS_IOCTL_GET_BDESCS ioctl
+ * is used by nilfs_cleanerd daemon.
+ *
+ * Return value: count of nilfs_bdescs structures in output buffer.
+ */
static ssize_t
nilfs_ioctl_do_get_bdescs(struct the_nilfs *nilfs, __u64 *posp, int flags,
void *buf, size_t size, size_t nmembs)
@@ -329,6 +497,29 @@ nilfs_ioctl_do_get_bdescs(struct the_nilfs *nilfs, __u64 *posp, int flags,
return nmembs;
}
+/**
+ * nilfs_ioctl_get_bdescs - get disk block descriptors
+ * @inode: inode object
+ * @filp: file object
+ * @cmd: ioctl's request code
+ * @argp: pointer on argument from userspace
+ *
+ * Description: nilfs_ioctl_do_get_bdescs() function returns information
+ * about descriptors of disk block numbers. The NILFS_IOCTL_GET_BDESCS ioctl
+ * is used by nilfs_cleanerd daemon.
+ *
+ * Return Value: On success, 0 is returned, and disk block descriptors are
+ * copied into userspace pointer @argp. On error, one of the following
+ * negative error codes is returned.
+ *
+ * %-EINVAL - Invalid arguments from userspace.
+ *
+ * %-EIO - I/O error.
+ *
+ * %-ENOMEM - Insufficient amount of memory available.
+ *
+ * %-EFAULT - Failure during getting disk block descriptors.
+ */
static int nilfs_ioctl_get_bdescs(struct inode *inode, struct file *filp,
unsigned int cmd, void __user *argp)
{
@@ -352,6 +543,26 @@ static int nilfs_ioctl_get_bdescs(struct inode *inode, struct file *filp,
return ret;
}
+/**
+ * nilfs_ioctl_move_inode_block - prepare data/node block for moving by GC
+ * @inode: inode object
+ * @vdesc: descriptor of virtual block number
+ * @buffers: list of moving buffers
+ *
+ * Description: nilfs_ioctl_move_inode_block() function registers data/node
+ * buffer in the GC pagecache and submit read request.
+ *
+ * Return Value: On success, 0 is returned. On error, one of the following
+ * negative error codes is returned.
+ *
+ * %-EIO - I/O error.
+ *
+ * %-ENOMEM - Insufficient amount of memory available.
+ *
+ * %-ENOENT - Requested block doesn't exist.
+ *
+ * %-EEXIST - Blocks conflict is detected.
+ */
static int nilfs_ioctl_move_inode_block(struct inode *inode,
struct nilfs_vdesc *vdesc,
struct list_head *buffers)
@@ -397,6 +608,19 @@ static int nilfs_ioctl_move_inode_block(struct inode *inode,
return 0;
}
+/**
+ * nilfs_ioctl_move_blocks - move valid inode's blocks during garbage collection
+ * @sb: superblock object
+ * @argv: vector of arguments from userspace
+ * @buf: array of nilfs_vdesc structures
+ *
+ * Description: nilfs_ioctl_move_blocks() function reads valid data/node
+ * blocks that garbage collector specified with the array of nilfs_vdesc
+ * structures and stores them into page caches of GC inodes.
+ *
+ * Return Value: Number of processed nilfs_vdesc structures or
+ * error code, otherwise.
+ */
static int nilfs_ioctl_move_blocks(struct super_block *sb,
struct nilfs_argv *argv, void *buf)
{
@@ -462,6 +686,25 @@ static int nilfs_ioctl_move_blocks(struct super_block *sb,
return ret;
}
+/**
+ * nilfs_ioctl_delete_checkpoints - delete checkpoints
+ * @nilfs: nilfs object
+ * @argv: vector of arguments from userspace
+ * @buf: array of periods of checkpoints numbers
+ *
+ * Description: nilfs_ioctl_delete_checkpoints() function deletes checkpoints
+ * in the period from p_start to p_end, excluding p_end itself. The checkpoints
+ * which have been already deleted are ignored.
+ *
+ * Return Value: Number of processed nilfs_period structures or
+ * error code, otherwise.
+ *
+ * %-EIO - I/O error.
+ *
+ * %-ENOMEM - Insufficient amount of memory available.
+ *
+ * %-EINVAL - invalid checkpoints.
+ */
static int nilfs_ioctl_delete_checkpoints(struct the_nilfs *nilfs,
struct nilfs_argv *argv, void *buf)
{
@@ -479,6 +722,24 @@ static int nilfs_ioctl_delete_checkpoints(struct the_nilfs *nilfs,
return nmembs;
}
+/**
+ * nilfs_ioctl_free_vblocknrs - free virtual block numbers
+ * @nilfs: nilfs object
+ * @argv: vector of arguments from userspace
+ * @buf: array of virtual block numbers
+ *
+ * Description: nilfs_ioctl_free_vblocknrs() function frees
+ * the virtual block numbers specified by @buf and @argv->v_nmembs.
+ *
+ * Return Value: Number of processed virtual block numbers or
+ * error code, otherwise.
+ *
+ * %-EIO - I/O error.
+ *
+ * %-ENOMEM - Insufficient amount of memory available.
+ *
+ * %-ENOENT - The virtual block number have not been allocated.
+ */
static int nilfs_ioctl_free_vblocknrs(struct the_nilfs *nilfs,
struct nilfs_argv *argv, void *buf)
{
@@ -490,6 +751,24 @@ static int nilfs_ioctl_free_vblocknrs(struct the_nilfs *nilfs,
return (ret < 0) ? ret : nmembs;
}
+/**
+ * nilfs_ioctl_mark_blocks_dirty - mark blocks dirty
+ * @nilfs: nilfs object
+ * @argv: vector of arguments from userspace
+ * @buf: array of block descriptors
+ *
+ * Description: nilfs_ioctl_mark_blocks_dirty() function marks
+ * metadata file or data blocks as dirty.
+ *
+ * Return Value: Number of processed block descriptors or
+ * error code, otherwise.
+ *
+ * %-ENOMEM - Insufficient memory available.
+ *
+ * %-EIO - I/O error
+ *
+ * %-ENOENT - the specified block does not exist (hole block)
+ */
static int nilfs_ioctl_mark_blocks_dirty(struct the_nilfs *nilfs,
struct nilfs_argv *argv, void *buf)
{
@@ -571,6 +850,20 @@ int nilfs_ioctl_prepare_clean_segments(struct the_nilfs *nilfs,
return ret;
}
+/**
+ * nilfs_ioctl_clean_segments - clean segments
+ * @inode: inode object
+ * @filp: file object
+ * @cmd: ioctl's request code
+ * @argp: pointer on argument from userspace
+ *
+ * Description: nilfs_ioctl_clean_segments() function makes garbage
+ * collection operation in the environment of requested parameters
+ * from userspace. The NILFS_IOCTL_CLEAN_SEGMENTS ioctl is used by
+ * nilfs_cleanerd daemon.
+ *
+ * Return Value: On success, 0 is returned or error code, otherwise.
+ */
static int nilfs_ioctl_clean_segments(struct inode *inode, struct file *filp,
unsigned int cmd, void __user *argp)
{
@@ -682,6 +975,33 @@ out:
return ret;
}
+/**
+ * nilfs_ioctl_sync - make a checkpoint
+ * @inode: inode object
+ * @filp: file object
+ * @cmd: ioctl's request code
+ * @argp: pointer on argument from userspace
+ *
+ * Description: nilfs_ioctl_sync() function constructs a logical segment
+ * for checkpointing. This function guarantees that all modified data
+ * and metadata are written out to the device when it successfully
+ * returned.
+ *
+ * Return Value: On success, 0 is retured. On errors, one of the following
+ * negative error code is returned.
+ *
+ * %-EROFS - Read only filesystem.
+ *
+ * %-EIO - I/O error
+ *
+ * %-ENOSPC - No space left on device (only in a panic state).
+ *
+ * %-ERESTARTSYS - Interrupted.
+ *
+ * %-ENOMEM - Insufficient memory available.
+ *
+ * %-EFAULT - Failure during execution of requested operation.
+ */
static int nilfs_ioctl_sync(struct inode *inode, struct file *filp,
unsigned int cmd, void __user *argp)
{
@@ -710,6 +1030,14 @@ static int nilfs_ioctl_sync(struct inode *inode, struct file *filp,
return 0;
}
+/**
+ * nilfs_ioctl_resize - resize NILFS2 volume
+ * @inode: inode object
+ * @filp: file object
+ * @argp: pointer on argument from userspace
+ *
+ * Return Value: On success, 0 is returned or error code, otherwise.
+ */
static int nilfs_ioctl_resize(struct inode *inode, struct file *filp,
void __user *argp)
{
@@ -735,6 +1063,17 @@ out:
return ret;
}
+/**
+ * nilfs_ioctl_set_alloc_range - limit range of segments to be allocated
+ * @inode: inode object
+ * @argp: pointer on argument from userspace
+ *
+ * Decription: nilfs_ioctl_set_alloc_range() function defines lower limit
+ * of segments in bytes and upper limit of segments in bytes.
+ * The NILFS_IOCTL_SET_ALLOC_RANGE is used by nilfs_resize utility.
+ *
+ * Return Value: On success, 0 is returned or error code, otherwise.
+ */
static int nilfs_ioctl_set_alloc_range(struct inode *inode, void __user *argp)
{
struct the_nilfs *nilfs = inode->i_sb->s_fs_info;
@@ -767,6 +1106,28 @@ out:
return ret;
}
+/**
+ * nilfs_ioctl_get_info - wrapping function of get metadata info
+ * @inode: inode object
+ * @filp: file object
+ * @cmd: ioctl's request code
+ * @argp: pointer on argument from userspace
+ * @membsz: size of an item in bytes
+ * @dofunc: concrete function of getting metadata info
+ *
+ * Description: nilfs_ioctl_get_info() gets metadata info by means of
+ * calling dofunc() function.
+ *
+ * Return Value: On success, 0 is returned and requested metadata info
+ * is copied into userspace. On error, one of the following
+ * negative error codes is returned.
+ *
+ * %-EINVAL - Invalid arguments from userspace.
+ *
+ * %-ENOMEM - Insufficient amount of memory available.
+ *
+ * %-EFAULT - Failure during execution of requested operation.
+ */
static int nilfs_ioctl_get_info(struct inode *inode, struct file *filp,
unsigned int cmd, void __user *argp,
size_t membsz,
--
1.7.9.5
--
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