From: Steven Cavanagh <[EMAIL PROTECTED]> Added support for fallocate for a msdos fat driver. This allows preallocation of clusters to an inode before writes to reduce file fragmentation
Signed-off-by: Steven.Cavanagh <[EMAIL PROTECTED]> --- fs/fat/file.c | 45 +++++++++++++++++++++++++++++++++++++++++++++ 1 files changed, 45 insertions(+), 0 deletions(-) diff --git a/fs/fat/file.c b/fs/fat/file.c index 69a83b5..f753c6a 100644 --- a/fs/fat/file.c +++ b/fs/fat/file.c @@ -15,6 +15,7 @@ #include <linux/buffer_head.h> #include <linux/writeback.h> #include <linux/backing-dev.h> #include <linux/blkdev.h> +#include <linux/falloc.h> int fat_generic_ioctl(struct inode *inode, struct file *filp, unsigned int cmd, unsigned long arg) @@ -312,8 +313,52 @@ int fat_getattr(struct vfsmount *mnt, st } EXPORT_SYMBOL_GPL(fat_getattr); +/* + * preallocate space for a file. This implements fat fallocate inode + * operation, which gets called from sys_fallocate system call. User + * space requests len bytes at offset. + */ +long fat_fallocate(struct inode *inode, int mode, loff_t offset, loff_t len) +{ + int ret = 0; + loff_t filesize = inode->i_size; + + /* preallocation to directories is currently not supported */ + if (S_ISDIR(inode->i_mode)) { + printk(KERN_ERR + "fat_fallocate(): Directory prealloc not supported\n"); + return -ENODEV; + } + + if ((offset + len) <= MSDOS_I(inode)->mmu_private) { + printk(KERN_INFO + "fat_fallocate():Blocks already allocated\n"); + return 0; + } + + if ((offset + len) > MSDOS_I(inode)->mmu_private) { + + mutex_lock(&inode->i_mutex); + ret = fat_cont_expand(inode, (offset + len)); + if (ret) { + printk(KERN_ERR + "fat_fallocate():fat_cont_expand() error\n"); + mutex_unlock(&inode->i_mutex); + return ret; + } + mutex_unlock(&inode->i_mutex); + } + if (mode & FALLOC_FL_KEEP_SIZE) { + mutex_lock(&inode->i_mutex); + i_size_write(inode, filesize); + mutex_unlock(&inode->i_mutex); + } + return ret; +} + const struct inode_operations fat_file_inode_operations = { .truncate = fat_truncate, .setattr = fat_notify_change, .getattr = fat_getattr, + .fallocate = fat_fallocate, }; -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/