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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 | /* * linux/fs/ext2/file.c * * Copyright (C) 1992, 1993, 1994, 1995 * Remy Card (card@masi.ibp.fr) * Laboratoire MASI - Institut Blaise Pascal * Universite Pierre et Marie Curie (Paris VI) * * from * * linux/fs/minix/file.c * * Copyright (C) 1991, 1992 Linus Torvalds * * ext2 fs regular file handling primitives * * 64-bit file support on 64-bit platforms by Jakub Jelinek * (jj@sunsite.ms.mff.cuni.cz) */ #include <linux/fs.h> #include <linux/sched.h> #define NBUF 32 #define MIN(a,b) (((a)<(b))?(a):(b)) #define MAX(a,b) (((a)>(b))?(a):(b)) static loff_t ext2_file_lseek(struct file *, loff_t, int); static int ext2_open_file (struct inode *, struct file *); #define EXT2_MAX_SIZE(bits) \ (((EXT2_NDIR_BLOCKS + (1LL << (bits - 2)) + \ (1LL << (bits - 2)) * (1LL << (bits - 2)) + \ (1LL << (bits - 2)) * (1LL << (bits - 2)) * (1LL << (bits - 2))) * \ (1LL << bits)) - 1) static long long ext2_max_sizes[] = { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, EXT2_MAX_SIZE(10), EXT2_MAX_SIZE(11), EXT2_MAX_SIZE(12), EXT2_MAX_SIZE(13) }; /* * Make sure the offset never goes beyond the 32-bit mark.. */ static loff_t ext2_file_lseek( struct file *file, loff_t offset, int origin) { struct inode *inode = file->f_dentry->d_inode; switch (origin) { case 2: offset += inode->i_size; break; case 1: offset += file->f_pos; } if (offset<0) return -EINVAL; if (((unsigned long long) offset >> 32) != 0) { if (offset > ext2_max_sizes[EXT2_BLOCK_SIZE_BITS(inode->i_sb)]) return -EINVAL; } if (offset != file->f_pos) { file->f_pos = offset; file->f_reada = 0; file->f_version = ++event; } return offset; } static inline void remove_suid(struct inode *inode) { unsigned int mode; /* set S_IGID if S_IXGRP is set, and always set S_ISUID */ mode = (inode->i_mode & S_IXGRP)*(S_ISGID/S_IXGRP) | S_ISUID; /* was any of the uid bits set? */ mode &= inode->i_mode; if (mode && !capable(CAP_FSETID)) { inode->i_mode &= ~mode; mark_inode_dirty(inode); } } /* * Write to a file (through the page cache). */ static ssize_t ext2_file_write(struct file *file, const char *buf, size_t count, loff_t *ppos) { ssize_t retval; retval = generic_file_write(file, buf, count, ppos, block_write_partial_page); if (retval > 0) { struct inode *inode = file->f_dentry->d_inode; remove_suid(inode); inode->i_ctime = inode->i_mtime = CURRENT_TIME; mark_inode_dirty(inode); } return retval; } /* * Called when an inode is released. Note that this is different * from ext2_file_open: open gets called at every open, but release * gets called only when /all/ the files are closed. */ static int ext2_release_file (struct inode * inode, struct file * filp) { if (filp->f_mode & FMODE_WRITE) ext2_discard_prealloc (inode); return 0; } /* * Called when an inode is about to be open. * We use this to disallow opening RW large files on 32bit systems if * the caller didn't specify O_LARGEFILE. On 64bit systems we force * on this flag in sys_open. */ static int ext2_open_file (struct inode * inode, struct file * filp) { if (inode->u.ext2_i.i_high_size && !(filp->f_flags & O_LARGEFILE)) return -EFBIG; return 0; } /* * We have mostly NULL's here: the current defaults are ok for * the ext2 filesystem. */ static struct file_operations ext2_file_operations = { ext2_file_lseek, /* lseek */ generic_file_read, /* read */ ext2_file_write, /* write */ NULL, /* readdir - bad */ NULL, /* poll - default */ ext2_ioctl, /* ioctl */ generic_file_mmap, /* mmap */ ext2_open_file, NULL, /* flush */ ext2_release_file, /* release */ ext2_sync_file, /* fsync */ NULL, /* fasync */ }; struct inode_operations ext2_file_inode_operations = { &ext2_file_operations,/* default file operations */ NULL, /* create */ NULL, /* lookup */ NULL, /* link */ NULL, /* unlink */ NULL, /* symlink */ NULL, /* mkdir */ NULL, /* rmdir */ NULL, /* mknod */ NULL, /* rename */ NULL, /* readlink */ NULL, /* follow_link */ ext2_get_block, /* get_block */ block_read_full_page, /* readpage */ block_write_full_page, /* writepage */ ext2_truncate, /* truncate */ NULL, /* permission */ NULL, /* revalidate */ }; |