Implement fallocate
PATCH 1/1 Implement fallocate
XFS fallocate() callout.
Allocate the range requested as unwritten extents. Atomically change the file size if requested.
--- fs/xfs/linux-2.6/xfs_iops.c | 45 ++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 45 insertions(+)
fs/xfs/linux-2.6/xfs_iops.c +45 -0
@@ -52,6 +52,7 @@#include <linux/xattr.h> #include <linux/namei.h> #include <linux/security.h> +#include <linux/falloc.h> /* * Bring the atime in the XFS inode uptodate.
@@ -796,6 +797,49 @@ xfs_vn_removexattr(return namesp->attr_remove (vp, attr, xflags); } +/* +* generic space allocation vector. +*/ +STATIC long +xfs_vn_fallocate ( +struct inode *inode, +int mode, +loff_t offset, +loff_t len) +{ +long error; +loff_t new_size =0 ; +xfs_flock64_t bf; + +/* preallocation on directories not yet supported */ + error = -ENODEV ; +if (S_ISDIR (inode->i_mode)) + goto out_error; + + bf.l_whence =0 ; + bf.l_start = offset; + bf.l_len = len; + +xfs_ilock (XFS_I (inode),XFS_IOLOCK_EXCL ); + error =xfs_change_file_space (XFS_I (inode),XFS_IOC_RESVSP , &bf, +0 ,NULL ,ATTR_NOLOCK ); +if (!error && !(mode &FALLOC_FL_KEEP_SIZE ) && + offset + len >i_size_read (inode)) + new_size = offset + len; + +/* Change file size if needed */ +if (new_size) { +bhv_vattr_t va; + + va.va_mask =XFS_AT_SIZE ; + va.va_size = new_size; + error =xfs_setattr (XFS_I (inode), &va,ATTR_NOLOCK ,NULL ); + } + +xfs_iunlock (XFS_I (inode),XFS_IOLOCK_EXCL ); +out_error: +return error; +}const struct inode_operations xfs_inode_operations = { .permission = xfs_vn_permission,
@@ -806,6 +850,7 @@ const struct inode_operations xfs_inode_ .getxattr = xfs_vn_getxattr, .listxattr = xfs_vn_listxattr, .removexattr = xfs_vn_removexattr, + .fallocate = xfs_vn_fallocate, };const struct inode_operations xfs_dir_inode_operations = {
Quoted 3 lines · David Chinner
+/*
+ * generic space allocation vector.
+ */
This comment is rather non-sensical. But I think you can just kill it as inode operations don't really need comments.
Quoted 13 lines
fs/xfs/linux-2.6/xfs_iops.c +13
-0+STATIC long +xfs_vn_fallocate ( +struct inode *inode, +int mode, +loff_t offset, +loff_t len) +{ +long error; +loff_t new_size =0 ; +xfs_flock64_t bf; + +/* preallocation on directories not yet supported */ + error = -ENODEV ;
fs/xfs/linux-2.6/xfs_iops.c xfs_vn_removexattr( · line 825
Quoted 10 lines
fs/xfs/linux-2.6/xfs_iops.c +10
-0+if (S_ISDIR (inode->i_mode)) + goto out_error; + + bf.l_whence =0 ; + bf.l_start = offset; + bf.l_len = len; + +xfs_ilock (XFS_I (inode),XFS_IOLOCK_EXCL ); + error =xfs_change_file_space (XFS_I (inode),XFS_IOC_RESVSP , &bf, +0 ,NULL ,ATTR_NOLOCK );
please add a
struct xfs_inode *ip = XFS_I(inode);
to the beginning of the function and use it subsequently. That'll make the fun ction a little more readable.
Otherwise this looks fine to me.
Quoted 54 lines · David Chinner
XFS
fallocate()callout.Allocate the range requested as unwritten extents. Atomically change the file size if requested.
Signed-off-by Dave Chinner <[email protected]>--- fs/xfs/linux-2.6/xfs_iops.c | 45 ++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 45 insertions(+)Index:
2.6.x-xfs-new/fs/xfs/linux-2.6/xfs_iops.c
===================================================================fs/xfs/linux-2.6/xfs_iops.c +29
-0@@ -52,6 +52,7 @@#include <linux/xattr.h> #include <linux/namei.h> #include <linux/security.h> +#include <linux/falloc.h> /* * Bring the atime in the XFS inode uptodate. @@ -796,6 +797,49 @@ xfs_vn_removexattr(return namesp->attr_remove (vp, attr, xflags); } +/* +* generic space allocation vector. +*/ +STATIC long +xfs_vn_fallocate ( +struct inode *inode, +int mode, +loff_t offset, +loff_t len) +{ +long error; +loff_t new_size =0 ; +xfs_flock64_t bf; + +/* preallocation on directories not yet supported */ + error = -ENODEV ; +if (S_ISDIR (inode->i_mode)) + goto out_error; + + bf.l_whence =0 ; + bf.l_start = offset; + bf.l_len = len; + +xfs_ilock (XFS_I (inode),XFS_IOLOCK_EXCL ); + error =xfs_change_file_space (XFS_I (inode),XFS_IOC_RESVSP , &bf, +0 ,NULL ,ATTR_NOLOCK ); +if (!error && !(mode &FALLOC_FL_KEEP_SIZE ) && + offset + len >i_size_read (inode))
fs/xfs/linux-2.6/xfs_iops.c xfs_vn_removexattr( · line 837
Quoted 10 lines
fs/xfs/linux-2.6/xfs_iops.c +10
-0+ new_size = offset + len; + +/* Change file size if needed */ +if (new_size) { +bhv_vattr_t va; + + va.va_mask =XFS_AT_SIZE ; + va.va_size = new_size; + error =xfs_setattr (XFS_I (inode), &va,ATTR_NOLOCK ,NULL ); + }
Is it necessary to call xfs_setattr() here? Could we just do an explicit call to xfs_zero_eof(), set the new size, set i_update_core/size and mark the inode dirty? Hmmm, then again, that approach wouldn't be as clean as above.
Quoted 17 lines
fs/xfs/linux-2.6/xfs_iops.c +6
-0+ +xfs_iunlock (XFS_I (inode),XFS_IOLOCK_EXCL ); +out_error: +return error; +}const struct inode_operations xfs_inode_operations = { .permission = xfs_vn_permission,@@ -806,6 +850,7 @@ const struct inode_operations xfs_inode_ .getxattr = xfs_vn_getxattr, .listxattr = xfs_vn_listxattr, .removexattr = xfs_vn_removexattr, + .fallocate = xfs_vn_fallocate, };const struct inode_operations xfs_dir_inode_operations = {
Quoted 12 lines · Lachlan McIlroy
Quoted 12 lines
fs/xfs/linux-2.6/xfs_iops.c +12
-0+xfs_ilock (XFS_I (inode),XFS_IOLOCK_EXCL ); + error =xfs_change_file_space (XFS_I (inode),XFS_IOC_RESVSP , &bf, +0 ,NULL ,ATTR_NOLOCK ); +if (!error && !(mode &FALLOC_FL_KEEP_SIZE ) && + offset + len >i_size_read (inode)) + new_size = offset + len; + +/* Change file size if needed */ +if (new_size) { +bhv_vattr_t va; + + va.va_mask =XFS_AT_SIZE ;
Quoted 8 lines
fs/xfs/linux-2.6/xfs_iops.c xfs_vn_removexattr( · line 837
Quoted 3 lines
fs/xfs/linux-2.6/xfs_iops.c +3
-0+ va.va_size = new_size; + error =xfs_setattr (XFS_I (inode), &va,ATTR_NOLOCK ,NULL ); + }Is it necessary to call
xfs_setattr()here? Could we just do an explicit call toxfs_zero_eof(), set the new size, set i_update_core/size and mark the inode dirty? Hmmm, then again, that approach wouldn't be as clean as above.
And it also violates the atomicity that posix_fallocate is supposed to provide. i.e. if it returns success, the change of file size must be permanent. i.e. the change of size needs to be recorded in a transaction. Hence we need to call xfs_setattr....
Cheers,
Dave.
Signature · 3 lines
Dave Chinner Principal Engineer SGI Australian Software Group