[5,2/4] Return 32/64-bit dir name hash according to usage type

Message ID	20120109132148.2616029.68798.stgit@localhost.localdomain
State	Superseded, archived
Headers	show Return-Path: <linux-ext4-owner@vger.kernel.org> Subject: [PATCH 5 2/4] Return 32/64-bit dir name hash according to usage type To: linux-nfs@vger.kernel.org, linux-ext4@vger.kernel.org From: Bernd Schubert <bernd.schubert@itwm.fraunhofer.de> Cc: linux-fsdevel@vger.kernel.org, Fan Yong <yong.fan@whamcloud.com>, bfields@redhat.com, sandeen@redhat.com, Andreas Dilger <adilger@whamcloud.com> Date: Mon, 09 Jan 2012 14:21:48 +0100 Message-ID: <20120109132148.2616029.68798.stgit@localhost.localdomain> In-Reply-To: <20120109132137.2616029.76288.stgit@localhost.localdomain> References: <20120109132137.2616029.76288.stgit@localhost.localdomain> User-Agent: StGit/0.15 MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Sender: linux-ext4-owner@vger.kernel.org Precedence: bulk

diff --git a/fs/ext4/dir.c b/fs/ext4/dir.c index 164c560..cee09f2 100644 --- a/fs/ext4/dir.c +++ b/fs/ext4/dir.c @@ -32,24 +32,8 @@ static unsigned char ext4_filetype_table[] = { DT_UNKNOWN, DT_REG, DT_DIR, DT_CHR, DT_BLK, DT_FIFO, DT_SOCK, DT_LNK }; -static int ext4_readdir(struct file *, void *, filldir_t); static int ext4_dx_readdir(struct file *filp, void *dirent, filldir_t filldir); -static int ext4_release_dir(struct inode *inode, - struct file *filp); - -const struct file_operations ext4_dir_operations = { - .llseek = ext4_llseek, - .read = generic_read_dir, - .readdir = ext4_readdir, /* we take BKL. needed?*/ - .unlocked_ioctl = ext4_ioctl, -#ifdef CONFIG_COMPAT - .compat_ioctl = ext4_compat_ioctl, -#endif - .fsync = ext4_sync_file, - .release = ext4_release_dir, -}; - static unsigned char get_dtype(struct super_block *sb, int filetype) { @@ -254,22 +238,134 @@ out: return ret; } +static inline int is_32bit_api(void) +{ +#ifdef CONFIG_COMPAT + return is_compat_task(); +#else + return (BITS_PER_LONG == 32); +#endif +} + /* * These functions convert from the major/minor hash to an f_pos - * value. + * value for dx directories * - * Currently we only use major hash numer. This is unfortunate, but - * on 32-bit machines, the same VFS interface is used for lseek and - * llseek, so if we use the 64 bit offset, then the 32-bit versions of - * lseek/telldir/seekdir will blow out spectacularly, and from within - * the ext2 low-level routine, we don't know if we're being called by - * a 64-bit version of the system call or the 32-bit version of the - * system call. Worse yet, NFSv2 only allows for a 32-bit readdir - * cookie. Sigh. + * Upper layer (for example NFS) should specify FMODE_32BITHASH or + * FMODE_64BITHASH explicitly. On the other hand, we allow ext4 to be mounted + * directly on both 32-bit and 64-bit nodes, under such case, neither + * FMODE_32BITHASH nor FMODE_64BITHASH is specified. */ -#define hash2pos(major, minor) (major >> 1) -#define pos2maj_hash(pos) ((pos << 1) & 0xffffffff) -#define pos2min_hash(pos) (0) +static inline loff_t hash2pos(struct file *filp, __u32 major, __u32 minor) +{ + if ((filp->f_flags & FMODE_32BITHASH) || + (!(filp->f_flags & FMODE_64BITHASH) && is_32bit_api())) + return major >> 1; + else + return ((__u64)(major >> 1) << 32) | (__u64)minor; +} + +static inline __u32 pos2maj_hash(struct file *filp, loff_t pos) +{ + if ((filp->f_flags & FMODE_32BITHASH) || + (!(filp->f_mode & FMODE_64BITHASH) && is_32bit_api())) + return (pos << 1) & 0xffffffff; + else + return ((pos >> 32) << 1) & 0xffffffff; +} + +static inline __u32 pos2min_hash(struct file *filp, loff_t pos) +{ + if ((filp->f_flags & FMODE_32BITHASH) || + (!(filp->f_flags & FMODE_64BITHASH) && is_32bit_api())) + return 0; + else + return pos & 0xffffffff; +} + +/* + * Return 32- or 64-bit end-of-file for dx directories + */ +static inline loff_t ext4_get_htree_eof(struct file *filp) +{ + if ((filp->f_mode & FMODE_32BITHASH) || + (!(filp->f_mode & FMODE_64BITHASH) && is_32bit_api())) + return EXT4_HTREE_EOF_32BIT; + else + return EXT4_HTREE_EOF_64BIT; +} + + +/* + * ext4_dir_llseek() based on generic_file_llseek() to handle both + * non-htree and htree directories, where the "offset" is in terms + * of the filename hash value instead of the byte offset. + * + * NOTE: offsets obtained *before* ext4_set_inode_flag(dir, EXT4_INODE_INDEX) + * will be invalid once the directory was converted into a dx directory + */ +loff_t ext4_dir_llseek(struct file *file, loff_t offset, int origin) +{ + struct inode *inode = file->f_mapping->host; + loff_t ret = -EINVAL; + int is_dx_dir = ext4_test_inode_flag(inode, EXT4_INODE_INDEX); + + mutex_lock(&inode->i_mutex); + + /* NOTE: relative offsets with dx directories might not work + * as expected, as it is difficult to figure out the + * correct offset between dx hashes */ + + switch (origin) { + case SEEK_END: + if (unlikely(offset > 0)) + goto out_err; /* not supported for directories */ + + /* so only negative offsets are left, does that have a + * meaning for directories at all? */ + if (is_dx_dir) + offset += ext4_get_htree_eof(file); + else + offset += inode->i_size; + break; + case SEEK_CUR: + /* + * Here we special-case the lseek(fd, 0, SEEK_CUR) + * position-querying operation. Avoid rewriting the "same" + * f_pos value back to the file because a concurrent read(), + * write() or lseek() might have altered it + */ + if (offset == 0) { + offset = file->f_pos; + goto out_ok; + } + + offset += file->f_pos; + break; + } + + if (unlikely(offset < 0)) + goto out_err; + + if (!is_dx_dir) { + if (offset > inode->i_sb->s_maxbytes) + goto out_err; + } else if (offset > ext4_get_htree_eof(file)) + goto out_err; + + /* Special lock needed here? */ + if (offset != file->f_pos) { + file->f_pos = offset; + file->f_version = 0; + } + +out_ok: + ret = offset; +out_err: + mutex_unlock(&inode->i_mutex); + + return ret; +} /* * This structure holds the nodes of the red-black tree used to store @@ -330,15 +426,16 @@ static void free_rb_tree_fname(struct rb_root *root) } -static struct dir_private_info *ext4_htree_create_dir_info(loff_t pos) +static struct dir_private_info *ext4_htree_create_dir_info(struct file *filp, + loff_t pos) { struct dir_private_info *p; p = kzalloc(sizeof(struct dir_private_info), GFP_KERNEL); if (!p) return NULL; - p->curr_hash = pos2maj_hash(pos); - p->curr_minor_hash = pos2min_hash(pos); + p->curr_hash = pos2maj_hash(filp, pos); + p->curr_minor_hash = pos2min_hash(filp, pos); return p; } @@ -429,7 +526,7 @@ static int call_filldir(struct file *filp, void *dirent, "null fname?!?\n"); return 0; } - curr_pos = hash2pos(fname->hash, fname->minor_hash); + curr_pos = hash2pos(filp, fname->hash, fname->minor_hash); while (fname) { error = filldir(dirent, fname->name, fname->name_len, curr_pos, @@ -454,13 +551,13 @@ static int ext4_dx_readdir(struct file *filp, int ret; if (!info) { - info = ext4_htree_create_dir_info(filp->f_pos); + info = ext4_htree_create_dir_info(filp, filp->f_pos); if (!info) return -ENOMEM; filp->private_data = info; } - if (filp->f_pos == EXT4_HTREE_EOF) + if (filp->f_pos == ext4_get_htree_eof(filp)) return 0; /* EOF */ /* Some one has messed with f_pos; reset the world */ @@ -468,8 +565,8 @@ static int ext4_dx_readdir(struct file *filp, free_rb_tree_fname(&info->root); info->curr_node = NULL; info->extra_fname = NULL; - info->curr_hash = pos2maj_hash(filp->f_pos); - info->curr_minor_hash = pos2min_hash(filp->f_pos); + info->curr_hash = pos2maj_hash(filp, filp->f_pos); + info->curr_minor_hash = pos2min_hash(filp, filp->f_pos); } /* @@ -501,7 +598,7 @@ static int ext4_dx_readdir(struct file *filp, if (ret < 0) return ret; if (ret == 0) { - filp->f_pos = EXT4_HTREE_EOF; + filp->f_pos = ext4_get_htree_eof(filp); break; } info->curr_node = rb_first(&info->root); @@ -521,7 +618,7 @@ static int ext4_dx_readdir(struct file *filp, info->curr_minor_hash = fname->minor_hash; } else { if (info->next_hash == ~0) { - filp->f_pos = EXT4_HTREE_EOF; + filp->f_pos = ext4_get_htree_eof(filp); break; } info->curr_hash = info->next_hash; @@ -540,3 +637,15 @@ static int ext4_release_dir(struct inode *inode, struct file *filp) return 0; } + +const struct file_operations ext4_dir_operations = { + .llseek = ext4_dir_llseek, + .read = generic_read_dir, + .readdir = ext4_readdir, + .unlocked_ioctl = ext4_ioctl, +#ifdef CONFIG_COMPAT + .compat_ioctl = ext4_compat_ioctl, +#endif + .fsync = ext4_sync_file, + .release = ext4_release_dir, +}; diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h index 1554b15..d3fe1ea 100644 --- a/fs/ext4/ext4.h +++ b/fs/ext4/ext4.h @@ -1599,7 +1599,11 @@ struct dx_hash_info u32 *seed; }; -#define EXT4_HTREE_EOF 0x7fffffff + +/* 32 and 64 bit signed EOF for dx directories */ +#define EXT4_HTREE_EOF_32BIT ((1UL << (32 - 1)) - 1) +#define EXT4_HTREE_EOF_64BIT ((1ULL << (64 - 1)) - 1) + /* * Control parameters used by ext4_htree_next_block diff --git a/fs/ext4/hash.c b/fs/ext4/hash.c index ac8f168..fa8e491 100644 --- a/fs/ext4/hash.c +++ b/fs/ext4/hash.c @@ -200,8 +200,8 @@ int ext4fs_dirhash(const char *name, int len, struct dx_hash_info *hinfo) return -1; } hash = hash & ~1; - if (hash == (EXT4_HTREE_EOF << 1)) - hash = (EXT4_HTREE_EOF-1) << 1; + if (hash == (EXT4_HTREE_EOF_32BIT << 1)) + hash = (EXT4_HTREE_EOF_32BIT - 1) << 1; hinfo->hash = hash; hinfo->minor_hash = minor_hash; return 0;

[5,2/4] Return 32/64-bit dir name hash according to usage type

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