Messages in this thread | | | From | OGAWA Hirofumi <> | Subject | Re: [PATCH v3] fat: editions to support fat_fallocate | Date | Sat, 09 Mar 2013 23:18:05 +0900 |
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Namjae Jeon <linkinjeon@gmail.com> writes:
> static int fat_file_release(struct inode *inode, struct file *filp) > { > + struct super_block *sb = inode->i_sb; > + loff_t mmu_private_ideal = (inode->i_size + (sb->s_blocksize-1)) & > + ~(sb->s_blocksize-1); > + if (mmu_private_ideal < MSDOS_I(inode)->mmu_private && > + filp->f_dentry->d_count == 1) > + fat_truncate_blocks(inode, inode->i_size);
Without locking, truncate is racy.
This choose ->release(). BTW, we would also be able to do this only ->evict_inode(), although I'm not thinking yet which one is better.
If you had conclusion, it would be nice to explain it.
> +static long fat_fallocate(struct file *file, int mode, > + loff_t offset, loff_t len) > +{ > > + if ((offset + len) <= MSDOS_I(inode)->mmu_private) { > + fat_msg(sb, KERN_ERR, > + "fat_fallocate():Blocks already allocated"); > + return -EINVAL; > + }
Also this looks like totally racy.
> static int fat_write_begin(struct file *file, struct address_space *mapping, > loff_t pos, unsigned len, unsigned flags, > struct page **pagep, void **fsdata) > { > int err; > + struct inode *inode = mapping->host; > + struct super_block *sb = inode->i_sb; > + loff_t mmu_private_actual = MSDOS_I(inode)->mmu_private; > + loff_t mmu_private_ideal = (inode->i_size + (sb->s_blocksize-1)) & > + ~(sb->s_blocksize-1); > + > + if ((mmu_private_actual > mmu_private_ideal) && (pos > inode->i_size)) { > + err = fat_zero_falloc_area(file, mapping, pos); > + if (err) > + fat_msg(sb, KERN_ERR, "error zeroing fallocated area"); > + } > > *pagep = NULL; > err = cont_write_begin(file, mapping, pos, len, flags,
Hm, only write_begin is enough to handle mmap, truncate, and etc.?
Thanks. -- OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
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